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* [PATCH v17 00/15] arm64: untag user pointers passed to the kernel
@ 2019-06-12 11:43 Andrey Konovalov
  2019-06-12 11:43 ` [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
                   ` (14 more replies)
  0 siblings, 15 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

=== Overview

arm64 has a feature called Top Byte Ignore, which allows to embed pointer
tags into the top byte of each pointer. Userspace programs (such as
HWASan, a memory debugging tool [1]) might use this feature and pass
tagged user pointers to the kernel through syscalls or other interfaces.

Right now the kernel is already able to handle user faults with tagged
pointers, due to these patches:

1. 81cddd65 ("arm64: traps: fix userspace cache maintenance emulation on a
             tagged pointer")
2. 7dcd9dd8 ("arm64: hw_breakpoint: fix watchpoint matching for tagged
	      pointers")
3. 276e9327 ("arm64: entry: improve data abort handling of tagged
	      pointers")

This patchset extends tagged pointer support to syscall arguments.

As per the proposed ABI change [3], tagged pointers are only allowed to be
passed to syscalls when they point to memory ranges obtained by anonymous
mmap() or sbrk() (see the patchset [3] for more details).

For non-memory syscalls this is done by untaging user pointers when the
kernel performs pointer checking to find out whether the pointer comes
from userspace (most notably in access_ok). The untagging is done only
when the pointer is being checked, the tag is preserved as the pointer
makes its way through the kernel and stays tagged when the kernel
dereferences the pointer when perfoming user memory accesses.

The mmap and mremap (only new_addr) syscalls do not currently accept
tagged addresses. Architectures may interpret the tag as a background
colour for the corresponding vma.

Other memory syscalls (mprotect, etc.) don't do user memory accesses but
rather deal with memory ranges, and untagged pointers are better suited to
describe memory ranges internally. Thus for memory syscalls we untag
pointers completely when they enter the kernel.

=== Other approaches

One of the alternative approaches to untagging that was considered is to
completely strip the pointer tag as the pointer enters the kernel with
some kind of a syscall wrapper, but that won't work with the countless
number of different ioctl calls. With this approach we would need a custom
wrapper for each ioctl variation, which doesn't seem practical.

An alternative approach to untagging pointers in memory syscalls prologues
is to inspead allow tagged pointers to be passed to find_vma() (and other
vma related functions) and untag them there. Unfortunately, a lot of
find_vma() callers then compare or subtract the returned vma start and end
fields against the pointer that was being searched. Thus this approach
would still require changing all find_vma() callers.

=== Testing

The following testing approaches has been taken to find potential issues
with user pointer untagging:

1. Static testing (with sparse [2] and separately with a custom static
   analyzer based on Clang) to track casts of __user pointers to integer
   types to find places where untagging needs to be done.

2. Static testing with grep to find parts of the kernel that call
   find_vma() (and other similar functions) or directly compare against
   vm_start/vm_end fields of vma.

3. Static testing with grep to find parts of the kernel that compare
   user pointers with TASK_SIZE or other similar consts and macros.

4. Dynamic testing: adding BUG_ON(has_tag(addr)) to find_vma() and running
   a modified syzkaller version that passes tagged pointers to the kernel.

Based on the results of the testing the requried patches have been added
to the patchset.

=== Notes

This patchset is meant to be merged together with "arm64 relaxed ABI" [3].

This patchset is a prerequisite for ARM's memory tagging hardware feature
support [4].

This patchset has been merged into the Pixel 2 & 3 kernel trees and is
now being used to enable testing of Pixel phones with HWASan.

Thanks!

[1] http://clang.llvm.org/docs/HardwareAssistedAddressSanitizerDesign.html

[2] https://github.com/lucvoo/sparse-dev/commit/5f960cb10f56ec2017c128ef9d16060e0145f292

[3] https://lkml.org/lkml/2019/3/18/819

[4] https://community.arm.com/processors/b/blog/posts/arm-a-profile-architecture-2018-developments-armv85a

=== History

Changes in v17:
- The "uaccess: add noop untagged_addr definition" patch is dropped, as it
  was merged into upstream named as "uaccess: add noop untagged_addr
  definition".
- Merged "mm, arm64: untag user pointers in do_pages_move" into
  "mm, arm64: untag user pointers passed to memory syscalls".
- Added "arm64: Introduce prctl() options to control the tagged user
  addresses ABI" patch from Catalin.
- Add tags_lib.so to tools/testing/selftests/arm64/.gitignore.
- Added a comment clarifying untagged in mremap.
- Moved untagging back into mlx4_get_umem_mr() for the IB patch.

Changes in v16:
- Moved untagging for memory syscalls from arm64 wrappers back to generic
  code.
- Dropped untagging for the following memory syscalls: brk, mmap, munmap;
  mremap (only dropped for new_address); mmap_pgoff (not used on arm64);
  remap_file_pages (deprecated); shmat, shmdt (work on shared memory).
- Changed kselftest to LD_PRELOAD a shared library that overrides malloc
  to return tagged pointers.
- Rebased onto 5.2-rc3.

Changes in v15:
- Removed unnecessary untagging from radeon_ttm_tt_set_userptr().
- Removed unnecessary untagging from amdgpu_ttm_tt_set_userptr().
- Moved untagging to validate_range() in userfaultfd code.
- Moved untagging to ib_uverbs_(re)reg_mr() from mlx4_get_umem_mr().
- Rebased onto 5.1.

Changes in v14:
- Moved untagging for most memory syscalls to an arm64 specific
  implementation, instead of doing that in the common code.
- Dropped "net, arm64: untag user pointers in tcp_zerocopy_receive", since
  the provided user pointers don't come from an anonymous map and thus are
  not covered by this ABI relaxation.
- Dropped "kernel, arm64: untag user pointers in prctl_set_mm*".
- Moved untagging from __check_mem_type() to tee_shm_register().
- Updated untagging for the amdgpu and radeon drivers to cover the MMU
  notifier, as suggested by Felix.
- Since this ABI relaxation doesn't actually allow tagged instruction
  pointers, dropped the following patches:
- Dropped "tracing, arm64: untag user pointers in seq_print_user_ip".
- Dropped "uprobes, arm64: untag user pointers in find_active_uprobe".
- Dropped "bpf, arm64: untag user pointers in stack_map_get_build_id_offset".
- Rebased onto 5.1-rc7 (37624b58).

Changes in v13:
- Simplified untagging in tcp_zerocopy_receive().
- Looked at find_vma() callers in drivers/, which allowed to identify a
  few other places where untagging is needed.
- Added patch "mm, arm64: untag user pointers in get_vaddr_frames".
- Added patch "drm/amdgpu, arm64: untag user pointers in
  amdgpu_ttm_tt_get_user_pages".
- Added patch "drm/radeon, arm64: untag user pointers in
  radeon_ttm_tt_pin_userptr".
- Added patch "IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr".
- Added patch "media/v4l2-core, arm64: untag user pointers in
  videobuf_dma_contig_user_get".
- Added patch "tee/optee, arm64: untag user pointers in check_mem_type".
- Added patch "vfio/type1, arm64: untag user pointers".

Changes in v12:
- Changed untagging in tcp_zerocopy_receive() to also untag zc->address.
- Fixed untagging in prctl_set_mm* to only untag pointers for vma lookups
  and validity checks, but leave them as is for actual user space accesses.
- Updated the link to the v2 of the "arm64 relaxed ABI" patchset [3].
- Dropped the documentation patch, as the "arm64 relaxed ABI" patchset [3]
  handles that.

Changes in v11:
- Added "uprobes, arm64: untag user pointers in find_active_uprobe" patch.
- Added "bpf, arm64: untag user pointers in stack_map_get_build_id_offset"
  patch.
- Fixed "tracing, arm64: untag user pointers in seq_print_user_ip" to
  correctly perform subtration with a tagged addr.
- Moved untagged_addr() from SYSCALL_DEFINE3(mprotect) and
  SYSCALL_DEFINE4(pkey_mprotect) to do_mprotect_pkey().
- Moved untagged_addr() definition for other arches from
  include/linux/memory.h to include/linux/mm.h.
- Changed untagging in strn*_user() to perform userspace accesses through
  tagged pointers.
- Updated the documentation to mention that passing tagged pointers to
  memory syscalls is allowed.
- Updated the test to use malloc'ed memory instead of stack memory.

Changes in v10:
- Added "mm, arm64: untag user pointers passed to memory syscalls" back.
- New patch "fs, arm64: untag user pointers in fs/userfaultfd.c".
- New patch "net, arm64: untag user pointers in tcp_zerocopy_receive".
- New patch "kernel, arm64: untag user pointers in prctl_set_mm*".
- New patch "tracing, arm64: untag user pointers in seq_print_user_ip".

Changes in v9:
- Rebased onto 4.20-rc6.
- Used u64 instead of __u64 in type casts in the untagged_addr macro for
  arm64.
- Added braces around (addr) in the untagged_addr macro for other arches.

Changes in v8:
- Rebased onto 65102238 (4.20-rc1).
- Added a note to the cover letter on why syscall wrappers/shims that untag
  user pointers won't work.
- Added a note to the cover letter that this patchset has been merged into
  the Pixel 2 kernel tree.
- Documentation fixes, in particular added a list of syscalls that don't
  support tagged user pointers.

Changes in v7:
- Rebased onto 17b57b18 (4.19-rc6).
- Dropped the "arm64: untag user address in __do_user_fault" patch, since
  the existing patches already handle user faults properly.
- Dropped the "usb, arm64: untag user addresses in devio" patch, since the
  passed pointer must come from a vma and therefore be untagged.
- Dropped the "arm64: annotate user pointers casts detected by sparse"
  patch (see the discussion to the replies of the v6 of this patchset).
- Added more context to the cover letter.
- Updated Documentation/arm64/tagged-pointers.txt.

Changes in v6:
- Added annotations for user pointer casts found by sparse.
- Rebased onto 050cdc6c (4.19-rc1+).

Changes in v5:
- Added 3 new patches that add untagging to places found with static
  analysis.
- Rebased onto 44c929e1 (4.18-rc8).

Changes in v4:
- Added a selftest for checking that passing tagged pointers to the
  kernel succeeds.
- Rebased onto 81e97f013 (4.18-rc1+).

Changes in v3:
- Rebased onto e5c51f30 (4.17-rc6+).
- Added linux-arch@ to the list of recipients.

Changes in v2:
- Rebased onto 2d618bdf (4.17-rc3+).
- Removed excessive untagging in gup.c.
- Removed untagging pointers returned from __uaccess_mask_ptr.

Changes in v1:
- Rebased onto 4.17-rc1.

Changes in RFC v2:
- Added "#ifndef untagged_addr..." fallback in linux/uaccess.h instead of
  defining it for each arch individually.
- Updated Documentation/arm64/tagged-pointers.txt.
- Dropped "mm, arm64: untag user addresses in memory syscalls".
- Rebased onto 3eb2ce82 (4.16-rc7).

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Andrey Konovalov (14):
  arm64: untag user pointers in access_ok and __uaccess_mask_ptr
  lib, arm64: untag user pointers in strn*_user
  mm, arm64: untag user pointers passed to memory syscalls
  mm, arm64: untag user pointers in mm/gup.c
  mm, arm64: untag user pointers in get_vaddr_frames
  fs, arm64: untag user pointers in copy_mount_options
  userfaultfd, arm64: untag user pointers
  drm/amdgpu, arm64: untag user pointers
  drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl
  IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr
  media/v4l2-core, arm64: untag user pointers in
    videobuf_dma_contig_user_get
  tee/shm, arm64: untag user pointers in tee_shm_register
  vfio/type1, arm64: untag user pointers in vaddr_get_pfn
  selftests, arm64: add a selftest for passing tagged pointers to kernel

Catalin Marinas (1):
  arm64: Introduce prctl() options to control the tagged user addresses
    ABI

 arch/arm64/include/asm/processor.h            |  6 ++
 arch/arm64/include/asm/thread_info.h          |  1 +
 arch/arm64/include/asm/uaccess.h              | 11 ++-
 arch/arm64/kernel/process.c                   | 67 +++++++++++++++++++
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  |  2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c       |  2 +
 drivers/gpu/drm/radeon/radeon_gem.c           |  2 +
 drivers/infiniband/hw/mlx4/mr.c               |  7 +-
 drivers/media/v4l2-core/videobuf-dma-contig.c |  9 +--
 drivers/tee/tee_shm.c                         |  1 +
 drivers/vfio/vfio_iommu_type1.c               |  2 +
 fs/namespace.c                                |  2 +-
 fs/userfaultfd.c                              | 22 +++---
 include/uapi/linux/prctl.h                    |  5 ++
 kernel/sys.c                                  | 16 +++++
 lib/strncpy_from_user.c                       |  3 +-
 lib/strnlen_user.c                            |  3 +-
 mm/frame_vector.c                             |  2 +
 mm/gup.c                                      |  4 ++
 mm/madvise.c                                  |  2 +
 mm/mempolicy.c                                |  3 +
 mm/migrate.c                                  |  2 +-
 mm/mincore.c                                  |  2 +
 mm/mlock.c                                    |  4 ++
 mm/mprotect.c                                 |  2 +
 mm/mremap.c                                   |  7 ++
 mm/msync.c                                    |  2 +
 tools/testing/selftests/arm64/.gitignore      |  2 +
 tools/testing/selftests/arm64/Makefile        | 22 ++++++
 .../testing/selftests/arm64/run_tags_test.sh  | 12 ++++
 tools/testing/selftests/arm64/tags_lib.c      | 62 +++++++++++++++++
 tools/testing/selftests/arm64/tags_test.c     | 18 +++++
 32 files changed, 282 insertions(+), 25 deletions(-)
 create mode 100644 tools/testing/selftests/arm64/.gitignore
 create mode 100644 tools/testing/selftests/arm64/Makefile
 create mode 100755 tools/testing/selftests/arm64/run_tags_test.sh
 create mode 100644 tools/testing/selftests/arm64/tags_lib.c
 create mode 100644 tools/testing/selftests/arm64/tags_test.c

-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 14:26   ` Vincenzo Frascino
  2019-06-12 11:43 ` [PATCH v17 02/15] lib, arm64: untag user pointers in strn*_user Andrey Konovalov
                   ` (13 subsequent siblings)
  14 siblings, 1 reply; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

copy_from_user (and a few other similar functions) are used to copy data
from user memory into the kernel memory or vice versa. Since a user can
provided a tagged pointer to one of the syscalls that use copy_from_user,
we need to correctly handle such pointers.

Do this by untagging user pointers in access_ok and in __uaccess_mask_ptr,
before performing access validity checks.

Note, that this patch only temporarily untags the pointers to perform the
checks, but then passes them as is into the kernel internals.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 arch/arm64/include/asm/uaccess.h | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index e5d5f31c6d36..df729afca0ba 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -73,6 +73,8 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si
 {
 	unsigned long ret, limit = current_thread_info()->addr_limit;
 
+	addr = untagged_addr(addr);
+
 	__chk_user_ptr(addr);
 	asm volatile(
 	// A + B <= C + 1 for all A,B,C, in four easy steps:
@@ -226,7 +228,8 @@ static inline void uaccess_enable_not_uao(void)
 
 /*
  * Sanitise a uaccess pointer such that it becomes NULL if above the
- * current addr_limit.
+ * current addr_limit. In case the pointer is tagged (has the top byte set),
+ * untag the pointer before checking.
  */
 #define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr)
 static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
@@ -234,10 +237,11 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
 	void __user *safe_ptr;
 
 	asm volatile(
-	"	bics	xzr, %1, %2\n"
+	"	bics	xzr, %3, %2\n"
 	"	csel	%0, %1, xzr, eq\n"
 	: "=&r" (safe_ptr)
-	: "r" (ptr), "r" (current_thread_info()->addr_limit)
+	: "r" (ptr), "r" (current_thread_info()->addr_limit),
+	  "r" (untagged_addr(ptr))
 	: "cc");
 
 	csdb();
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 02/15] lib, arm64: untag user pointers in strn*_user
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
  2019-06-12 11:43 ` [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 14:28   ` Vincenzo Frascino
  2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
                   ` (12 subsequent siblings)
  14 siblings, 1 reply; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

strncpy_from_user and strnlen_user accept user addresses as arguments, and
do not go through the same path as copy_from_user and others, so here we
need to handle the case of tagged user addresses separately.

Untag user pointers passed to these functions.

Note, that this patch only temporarily untags the pointers to perform
validity checks, but then uses them as is to perform user memory accesses.

Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 lib/strncpy_from_user.c | 3 ++-
 lib/strnlen_user.c      | 3 ++-
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
index 023ba9f3b99f..dccb95af6003 100644
--- a/lib/strncpy_from_user.c
+++ b/lib/strncpy_from_user.c
@@ -6,6 +6,7 @@
 #include <linux/uaccess.h>
 #include <linux/kernel.h>
 #include <linux/errno.h>
+#include <linux/mm.h>
 
 #include <asm/byteorder.h>
 #include <asm/word-at-a-time.h>
@@ -108,7 +109,7 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
 		return 0;
 
 	max_addr = user_addr_max();
-	src_addr = (unsigned long)src;
+	src_addr = (unsigned long)untagged_addr(src);
 	if (likely(src_addr < max_addr)) {
 		unsigned long max = max_addr - src_addr;
 		long retval;
diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c
index 7f2db3fe311f..28ff554a1be8 100644
--- a/lib/strnlen_user.c
+++ b/lib/strnlen_user.c
@@ -2,6 +2,7 @@
 #include <linux/kernel.h>
 #include <linux/export.h>
 #include <linux/uaccess.h>
+#include <linux/mm.h>
 
 #include <asm/word-at-a-time.h>
 
@@ -109,7 +110,7 @@ long strnlen_user(const char __user *str, long count)
 		return 0;
 
 	max_addr = user_addr_max();
-	src_addr = (unsigned long)str;
+	src_addr = (unsigned long)untagged_addr(str);
 	if (likely(src_addr < max_addr)) {
 		unsigned long max = max_addr - src_addr;
 		long retval;
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
  2019-06-12 11:43 ` [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
  2019-06-12 11:43 ` [PATCH v17 02/15] lib, arm64: untag user pointers in strn*_user Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 14:30   ` Vincenzo Frascino
                     ` (5 more replies)
  2019-06-12 11:43 ` [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov
                   ` (11 subsequent siblings)
  14 siblings, 6 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

From: Catalin Marinas <catalin.marinas@arm.com>

It is not desirable to relax the ABI to allow tagged user addresses into
the kernel indiscriminately. This patch introduces a prctl() interface
for enabling or disabling the tagged ABI with a global sysctl control
for preventing applications from enabling the relaxed ABI (meant for
testing user-space prctl() return error checking without reconfiguring
the kernel). The ABI properties are inherited by threads of the same
application and fork()'ed children but cleared on execve().

The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
MTE-specific settings like imprecise vs precise exceptions.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
---
 arch/arm64/include/asm/processor.h   |  6 +++
 arch/arm64/include/asm/thread_info.h |  1 +
 arch/arm64/include/asm/uaccess.h     |  3 +-
 arch/arm64/kernel/process.c          | 67 ++++++++++++++++++++++++++++
 include/uapi/linux/prctl.h           |  5 +++
 kernel/sys.c                         | 16 +++++++
 6 files changed, 97 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index fcd0e691b1ea..fee457456aa8 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -307,6 +307,12 @@ extern void __init minsigstksz_setup(void);
 /* PR_PAC_RESET_KEYS prctl */
 #define PAC_RESET_KEYS(tsk, arg)	ptrauth_prctl_reset_keys(tsk, arg)
 
+/* PR_TAGGED_ADDR prctl */
+long set_tagged_addr_ctrl(unsigned long arg);
+long get_tagged_addr_ctrl(void);
+#define SET_TAGGED_ADDR_CTRL(arg)	set_tagged_addr_ctrl(arg)
+#define GET_TAGGED_ADDR_CTRL()		get_tagged_addr_ctrl()
+
 /*
  * For CONFIG_GCC_PLUGIN_STACKLEAK
  *
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index f1d032be628a..354a31d2b737 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -99,6 +99,7 @@ void arch_release_task_struct(struct task_struct *tsk);
 #define TIF_SVE			23	/* Scalable Vector Extension in use */
 #define TIF_SVE_VL_INHERIT	24	/* Inherit sve_vl_onexec across exec */
 #define TIF_SSBD		25	/* Wants SSB mitigation */
+#define TIF_TAGGED_ADDR		26	/* Allow tagged user addresses */
 
 #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
 #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index df729afca0ba..995b9ea11a89 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -73,7 +73,8 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si
 {
 	unsigned long ret, limit = current_thread_info()->addr_limit;
 
-	addr = untagged_addr(addr);
+	if (test_thread_flag(TIF_TAGGED_ADDR))
+		addr = untagged_addr(addr);
 
 	__chk_user_ptr(addr);
 	asm volatile(
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index 3767fb21a5b8..69d0be1fc708 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -30,6 +30,7 @@
 #include <linux/kernel.h>
 #include <linux/mm.h>
 #include <linux/stddef.h>
+#include <linux/sysctl.h>
 #include <linux/unistd.h>
 #include <linux/user.h>
 #include <linux/delay.h>
@@ -323,6 +324,7 @@ void flush_thread(void)
 	fpsimd_flush_thread();
 	tls_thread_flush();
 	flush_ptrace_hw_breakpoint(current);
+	clear_thread_flag(TIF_TAGGED_ADDR);
 }
 
 void release_thread(struct task_struct *dead_task)
@@ -552,3 +554,68 @@ void arch_setup_new_exec(void)
 
 	ptrauth_thread_init_user(current);
 }
+
+/*
+ * Control the relaxed ABI allowing tagged user addresses into the kernel.
+ */
+static unsigned int tagged_addr_prctl_allowed = 1;
+
+long set_tagged_addr_ctrl(unsigned long arg)
+{
+	if (!tagged_addr_prctl_allowed)
+		return -EINVAL;
+	if (is_compat_task())
+		return -EINVAL;
+	if (arg & ~PR_TAGGED_ADDR_ENABLE)
+		return -EINVAL;
+
+	if (arg & PR_TAGGED_ADDR_ENABLE)
+		set_thread_flag(TIF_TAGGED_ADDR);
+	else
+		clear_thread_flag(TIF_TAGGED_ADDR);
+
+	return 0;
+}
+
+long get_tagged_addr_ctrl(void)
+{
+	if (!tagged_addr_prctl_allowed)
+		return -EINVAL;
+	if (is_compat_task())
+		return -EINVAL;
+
+	if (test_thread_flag(TIF_TAGGED_ADDR))
+		return PR_TAGGED_ADDR_ENABLE;
+
+	return 0;
+}
+
+/*
+ * Global sysctl to disable the tagged user addresses support. This control
+ * only prevents the tagged address ABI enabling via prctl() and does not
+ * disable it for tasks that already opted in to the relaxed ABI.
+ */
+static int zero;
+static int one = 1;
+
+static struct ctl_table tagged_addr_sysctl_table[] = {
+	{
+		.procname	= "tagged_addr",
+		.mode		= 0644,
+		.data		= &tagged_addr_prctl_allowed,
+		.maxlen		= sizeof(int),
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= &zero,
+		.extra2		= &one,
+	},
+	{ }
+};
+
+static int __init tagged_addr_init(void)
+{
+	if (!register_sysctl("abi", tagged_addr_sysctl_table))
+		return -EINVAL;
+	return 0;
+}
+
+core_initcall(tagged_addr_init);
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 094bb03b9cc2..2e927b3e9d6c 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -229,4 +229,9 @@ struct prctl_mm_map {
 # define PR_PAC_APDBKEY			(1UL << 3)
 # define PR_PAC_APGAKEY			(1UL << 4)
 
+/* Tagged user address controls for arm64 */
+#define PR_SET_TAGGED_ADDR_CTRL		55
+#define PR_GET_TAGGED_ADDR_CTRL		56
+# define PR_TAGGED_ADDR_ENABLE		(1UL << 0)
+
 #endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index 2969304c29fe..ec48396b4943 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -124,6 +124,12 @@
 #ifndef PAC_RESET_KEYS
 # define PAC_RESET_KEYS(a, b)	(-EINVAL)
 #endif
+#ifndef SET_TAGGED_ADDR_CTRL
+# define SET_TAGGED_ADDR_CTRL(a)	(-EINVAL)
+#endif
+#ifndef GET_TAGGED_ADDR_CTRL
+# define GET_TAGGED_ADDR_CTRL()		(-EINVAL)
+#endif
 
 /*
  * this is where the system-wide overflow UID and GID are defined, for
@@ -2492,6 +2498,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 			return -EINVAL;
 		error = PAC_RESET_KEYS(me, arg2);
 		break;
+	case PR_SET_TAGGED_ADDR_CTRL:
+		if (arg3 || arg4 || arg5)
+			return -EINVAL;
+		error = SET_TAGGED_ADDR_CTRL(arg2);
+		break;
+	case PR_GET_TAGGED_ADDR_CTRL:
+		if (arg2 || arg3 || arg4 || arg5)
+			return -EINVAL;
+		error = GET_TAGGED_ADDR_CTRL();
+		break;
 	default:
 		error = -EINVAL;
 		break;
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (2 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 14:31   ` Vincenzo Frascino
  2019-06-19 15:55   ` Khalid Aziz
  2019-06-12 11:43 ` [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
                   ` (10 subsequent siblings)
  14 siblings, 2 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

This patch allows tagged pointers to be passed to the following memory
syscalls: get_mempolicy, madvise, mbind, mincore, mlock, mlock2, mprotect,
mremap, msync, munlock, move_pages.

The mmap and mremap syscalls do not currently accept tagged addresses.
Architectures may interpret the tag as a background colour for the
corresponding vma.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/madvise.c   | 2 ++
 mm/mempolicy.c | 3 +++
 mm/migrate.c   | 2 +-
 mm/mincore.c   | 2 ++
 mm/mlock.c     | 4 ++++
 mm/mprotect.c  | 2 ++
 mm/mremap.c    | 7 +++++++
 mm/msync.c     | 2 ++
 8 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 628022e674a7..39b82f8a698f 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -810,6 +810,8 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
 	size_t len;
 	struct blk_plug plug;
 
+	start = untagged_addr(start);
+
 	if (!madvise_behavior_valid(behavior))
 		return error;
 
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 01600d80ae01..78e0a88b2680 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -1360,6 +1360,7 @@ static long kernel_mbind(unsigned long start, unsigned long len,
 	int err;
 	unsigned short mode_flags;
 
+	start = untagged_addr(start);
 	mode_flags = mode & MPOL_MODE_FLAGS;
 	mode &= ~MPOL_MODE_FLAGS;
 	if (mode >= MPOL_MAX)
@@ -1517,6 +1518,8 @@ static int kernel_get_mempolicy(int __user *policy,
 	int uninitialized_var(pval);
 	nodemask_t nodes;
 
+	addr = untagged_addr(addr);
+
 	if (nmask != NULL && maxnode < nr_node_ids)
 		return -EINVAL;
 
diff --git a/mm/migrate.c b/mm/migrate.c
index f2ecc2855a12..d22c45cf36b2 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1616,7 +1616,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
 			goto out_flush;
 		if (get_user(node, nodes + i))
 			goto out_flush;
-		addr = (unsigned long)p;
+		addr = (unsigned long)untagged_addr(p);
 
 		err = -ENODEV;
 		if (node < 0 || node >= MAX_NUMNODES)
diff --git a/mm/mincore.c b/mm/mincore.c
index c3f058bd0faf..64c322ed845c 100644
--- a/mm/mincore.c
+++ b/mm/mincore.c
@@ -249,6 +249,8 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
 	unsigned long pages;
 	unsigned char *tmp;
 
+	start = untagged_addr(start);
+
 	/* Check the start address: needs to be page-aligned.. */
 	if (start & ~PAGE_MASK)
 		return -EINVAL;
diff --git a/mm/mlock.c b/mm/mlock.c
index 080f3b36415b..e82609eaa428 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -674,6 +674,8 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla
 	unsigned long lock_limit;
 	int error = -ENOMEM;
 
+	start = untagged_addr(start);
+
 	if (!can_do_mlock())
 		return -EPERM;
 
@@ -735,6 +737,8 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
 {
 	int ret;
 
+	start = untagged_addr(start);
+
 	len = PAGE_ALIGN(len + (offset_in_page(start)));
 	start &= PAGE_MASK;
 
diff --git a/mm/mprotect.c b/mm/mprotect.c
index bf38dfbbb4b4..19f981b733bc 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -465,6 +465,8 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 	const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
 				(prot & PROT_READ);
 
+	start = untagged_addr(start);
+
 	prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
 	if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
 		return -EINVAL;
diff --git a/mm/mremap.c b/mm/mremap.c
index fc241d23cd97..64c9a3b8be0a 100644
--- a/mm/mremap.c
+++ b/mm/mremap.c
@@ -606,6 +606,13 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
 	LIST_HEAD(uf_unmap_early);
 	LIST_HEAD(uf_unmap);
 
+	/*
+	 * Architectures may interpret the tag passed to mmap as a background
+	 * colour for the corresponding vma. For mremap we don't allow tagged
+	 * new_addr to preserve similar behaviour to mmap.
+	 */
+	addr = untagged_addr(addr);
+
 	if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
 		return ret;
 
diff --git a/mm/msync.c b/mm/msync.c
index ef30a429623a..c3bd3e75f687 100644
--- a/mm/msync.c
+++ b/mm/msync.c
@@ -37,6 +37,8 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
 	int unmapped_error = 0;
 	int error = -EINVAL;
 
+	start = untagged_addr(start);
+
 	if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
 		goto out;
 	if (offset_in_page(start))
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (3 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 14:33   ` Vincenzo Frascino
  2019-06-19 16:41   ` Khalid Aziz
  2019-06-12 11:43 ` [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames Andrey Konovalov
                   ` (9 subsequent siblings)
  14 siblings, 2 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

mm/gup.c provides a kernel interface that accepts user addresses and
manipulates user pages directly (for example get_user_pages, that is used
by the futex syscall). Since a user can provided tagged addresses, we need
to handle this case.

Add untagging to gup.c functions that use user addresses for vma lookups.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/gup.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/mm/gup.c b/mm/gup.c
index ddde097cf9e4..c37df3d455a2 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -802,6 +802,8 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
 	if (!nr_pages)
 		return 0;
 
+	start = untagged_addr(start);
+
 	VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
 
 	/*
@@ -964,6 +966,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
 	struct vm_area_struct *vma;
 	vm_fault_t ret, major = 0;
 
+	address = untagged_addr(address);
+
 	if (unlocked)
 		fault_flags |= FAULT_FLAG_ALLOW_RETRY;
 
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (4 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 14:34   ` Vincenzo Frascino
  2019-06-19 16:48   ` Khalid Aziz
  2019-06-12 11:43 ` [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
                   ` (8 subsequent siblings)
  14 siblings, 2 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

get_vaddr_frames uses provided user pointers for vma lookups, which can
only by done with untagged pointers. Instead of locating and changing
all callers of this function, perform untagging in it.

Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 mm/frame_vector.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mm/frame_vector.c b/mm/frame_vector.c
index c64dca6e27c2..c431ca81dad5 100644
--- a/mm/frame_vector.c
+++ b/mm/frame_vector.c
@@ -46,6 +46,8 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
 	if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
 		nr_frames = vec->nr_allocated;
 
+	start = untagged_addr(start);
+
 	down_read(&mm->mmap_sem);
 	locked = 1;
 	vma = find_vma_intersection(mm, start, start + 1);
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (5 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 14:35   ` Vincenzo Frascino
  2019-06-19 20:01   ` Khalid Aziz
  2019-06-12 11:43 ` [PATCH v17 08/15] userfaultfd, arm64: untag user pointers Andrey Konovalov
                   ` (7 subsequent siblings)
  14 siblings, 2 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

In copy_mount_options a user address is being subtracted from TASK_SIZE.
If the address is lower than TASK_SIZE, the size is calculated to not
allow the exact_copy_from_user() call to cross TASK_SIZE boundary.
However if the address is tagged, then the size will be calculated
incorrectly.

Untag the address before subtracting.

Reviewed-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 fs/namespace.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/namespace.c b/fs/namespace.c
index b26778bdc236..2e85712a19ed 100644
--- a/fs/namespace.c
+++ b/fs/namespace.c
@@ -2993,7 +2993,7 @@ void *copy_mount_options(const void __user * data)
 	 * the remainder of the page.
 	 */
 	/* copy_from_user cannot cross TASK_SIZE ! */
-	size = TASK_SIZE - (unsigned long)data;
+	size = TASK_SIZE - (unsigned long)untagged_addr(data);
 	if (size > PAGE_SIZE)
 		size = PAGE_SIZE;
 
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 08/15] userfaultfd, arm64: untag user pointers
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (6 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 14:40   ` Vincenzo Frascino
  2019-06-12 11:43 ` [PATCH v17 09/15] drm/amdgpu, " Andrey Konovalov
                   ` (6 subsequent siblings)
  14 siblings, 1 reply; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

userfaultfd code use provided user pointers for vma lookups, which can
only by done with untagged pointers.

Untag user pointers in validate_range().

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 fs/userfaultfd.c | 22 ++++++++++++----------
 1 file changed, 12 insertions(+), 10 deletions(-)

diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index 3b30301c90ec..24d68c3b5ee2 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -1263,21 +1263,23 @@ static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx,
 }
 
 static __always_inline int validate_range(struct mm_struct *mm,
-					  __u64 start, __u64 len)
+					  __u64 *start, __u64 len)
 {
 	__u64 task_size = mm->task_size;
 
-	if (start & ~PAGE_MASK)
+	*start = untagged_addr(*start);
+
+	if (*start & ~PAGE_MASK)
 		return -EINVAL;
 	if (len & ~PAGE_MASK)
 		return -EINVAL;
 	if (!len)
 		return -EINVAL;
-	if (start < mmap_min_addr)
+	if (*start < mmap_min_addr)
 		return -EINVAL;
-	if (start >= task_size)
+	if (*start >= task_size)
 		return -EINVAL;
-	if (len > task_size - start)
+	if (len > task_size - *start)
 		return -EINVAL;
 	return 0;
 }
@@ -1327,7 +1329,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
 		goto out;
 	}
 
-	ret = validate_range(mm, uffdio_register.range.start,
+	ret = validate_range(mm, &uffdio_register.range.start,
 			     uffdio_register.range.len);
 	if (ret)
 		goto out;
@@ -1516,7 +1518,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
 	if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister)))
 		goto out;
 
-	ret = validate_range(mm, uffdio_unregister.start,
+	ret = validate_range(mm, &uffdio_unregister.start,
 			     uffdio_unregister.len);
 	if (ret)
 		goto out;
@@ -1667,7 +1669,7 @@ static int userfaultfd_wake(struct userfaultfd_ctx *ctx,
 	if (copy_from_user(&uffdio_wake, buf, sizeof(uffdio_wake)))
 		goto out;
 
-	ret = validate_range(ctx->mm, uffdio_wake.start, uffdio_wake.len);
+	ret = validate_range(ctx->mm, &uffdio_wake.start, uffdio_wake.len);
 	if (ret)
 		goto out;
 
@@ -1707,7 +1709,7 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
 			   sizeof(uffdio_copy)-sizeof(__s64)))
 		goto out;
 
-	ret = validate_range(ctx->mm, uffdio_copy.dst, uffdio_copy.len);
+	ret = validate_range(ctx->mm, &uffdio_copy.dst, uffdio_copy.len);
 	if (ret)
 		goto out;
 	/*
@@ -1763,7 +1765,7 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx,
 			   sizeof(uffdio_zeropage)-sizeof(__s64)))
 		goto out;
 
-	ret = validate_range(ctx->mm, uffdio_zeropage.range.start,
+	ret = validate_range(ctx->mm, &uffdio_zeropage.range.start,
 			     uffdio_zeropage.range.len);
 	if (ret)
 		goto out;
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 09/15] drm/amdgpu, arm64: untag user pointers
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (7 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 08/15] userfaultfd, arm64: untag user pointers Andrey Konovalov
@ 2019-06-12 11:43 ` " Andrey Konovalov
  2019-06-12 11:43 ` [PATCH v17 10/15] drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl Andrey Konovalov
                   ` (5 subsequent siblings)
  14 siblings, 0 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

In amdgpu_gem_userptr_ioctl() and amdgpu_amdkfd_gpuvm.c/init_user_pages()
an MMU notifier is set up with a (tagged) userspace pointer. The untagged
address should be used so that MMU notifiers for the untagged address get
correctly matched up with the right BO. This patch untag user pointers in
amdgpu_gem_userptr_ioctl() for the GEM case and in amdgpu_amdkfd_gpuvm_
alloc_memory_of_gpu() for the KFD case. This also makes sure that an
untagged pointer is passed to amdgpu_ttm_tt_get_user_pages(), which uses
it for vma lookups.

Suggested-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 +-
 drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c          | 2 ++
 2 files changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index a6e5184d436c..5d476e9bbc43 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1108,7 +1108,7 @@ int amdgpu_amdkfd_gpuvm_alloc_memory_of_gpu(
 		alloc_flags = 0;
 		if (!offset || !*offset)
 			return -EINVAL;
-		user_addr = *offset;
+		user_addr = untagged_addr(*offset);
 	} else if (flags & ALLOC_MEM_FLAGS_DOORBELL) {
 		domain = AMDGPU_GEM_DOMAIN_GTT;
 		alloc_domain = AMDGPU_GEM_DOMAIN_CPU;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
index d4fcf5475464..e91df1407618 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gem.c
@@ -287,6 +287,8 @@ int amdgpu_gem_userptr_ioctl(struct drm_device *dev, void *data,
 	uint32_t handle;
 	int r;
 
+	args->addr = untagged_addr(args->addr);
+
 	if (offset_in_page(args->addr | args->size))
 		return -EINVAL;
 
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 10/15] drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (8 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 09/15] drm/amdgpu, " Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 11:43 ` [PATCH v17 11/15] IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr Andrey Konovalov
                   ` (4 subsequent siblings)
  14 siblings, 0 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

In radeon_gem_userptr_ioctl() an MMU notifier is set up with a (tagged)
userspace pointer. The untagged address should be used so that MMU
notifiers for the untagged address get correctly matched up with the right
BO. This funcation also calls radeon_ttm_tt_pin_userptr(), which uses
provided user pointers for vma lookups, which can only by done with
untagged pointers.

This patch untags user pointers in radeon_gem_userptr_ioctl().

Suggested-by: Felix Kuehling <Felix.Kuehling@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 drivers/gpu/drm/radeon/radeon_gem.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/radeon/radeon_gem.c b/drivers/gpu/drm/radeon/radeon_gem.c
index 44617dec8183..90eb78fb5eb2 100644
--- a/drivers/gpu/drm/radeon/radeon_gem.c
+++ b/drivers/gpu/drm/radeon/radeon_gem.c
@@ -291,6 +291,8 @@ int radeon_gem_userptr_ioctl(struct drm_device *dev, void *data,
 	uint32_t handle;
 	int r;
 
+	args->addr = untagged_addr(args->addr);
+
 	if (offset_in_page(args->addr | args->size))
 		return -EINVAL;
 
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 11/15] IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (9 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 10/15] drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 11:43 ` [PATCH v17 12/15] media/v4l2-core, arm64: untag user pointers in videobuf_dma_contig_user_get Andrey Konovalov
                   ` (3 subsequent siblings)
  14 siblings, 0 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

mlx4_get_umem_mr() uses provided user pointers for vma lookups, which can
only by done with untagged pointers.

Untag user pointers in this function.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 drivers/infiniband/hw/mlx4/mr.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/infiniband/hw/mlx4/mr.c b/drivers/infiniband/hw/mlx4/mr.c
index 355205a28544..13d9f917f249 100644
--- a/drivers/infiniband/hw/mlx4/mr.c
+++ b/drivers/infiniband/hw/mlx4/mr.c
@@ -378,6 +378,7 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start,
 	 * again
 	 */
 	if (!ib_access_writable(access_flags)) {
+		unsigned long untagged_start = untagged_addr(start);
 		struct vm_area_struct *vma;
 
 		down_read(&current->mm->mmap_sem);
@@ -386,9 +387,9 @@ static struct ib_umem *mlx4_get_umem_mr(struct ib_udata *udata, u64 start,
 		 * cover the memory, but for now it requires a single vma to
 		 * entirely cover the MR to support RO mappings.
 		 */
-		vma = find_vma(current->mm, start);
-		if (vma && vma->vm_end >= start + length &&
-		    vma->vm_start <= start) {
+		vma = find_vma(current->mm, untagged_start);
+		if (vma && vma->vm_end >= untagged_start + length &&
+		    vma->vm_start <= untagged_start) {
 			if (vma->vm_flags & VM_WRITE)
 				access_flags |= IB_ACCESS_LOCAL_WRITE;
 		} else {
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 12/15] media/v4l2-core, arm64: untag user pointers in videobuf_dma_contig_user_get
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (10 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 11/15] IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-19 20:05   ` Khalid Aziz
  2019-06-12 11:43 ` [PATCH v17 13/15] tee/shm, arm64: untag user pointers in tee_shm_register Andrey Konovalov
                   ` (2 subsequent siblings)
  14 siblings, 1 reply; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov,
	Mauro Carvalho Chehab

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

videobuf_dma_contig_user_get() uses provided user pointers for vma
lookups, which can only by done with untagged pointers.

Untag the pointers in this function.

Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 drivers/media/v4l2-core/videobuf-dma-contig.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/media/v4l2-core/videobuf-dma-contig.c b/drivers/media/v4l2-core/videobuf-dma-contig.c
index e1bf50df4c70..8a1ddd146b17 100644
--- a/drivers/media/v4l2-core/videobuf-dma-contig.c
+++ b/drivers/media/v4l2-core/videobuf-dma-contig.c
@@ -160,6 +160,7 @@ static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
 static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
 					struct videobuf_buffer *vb)
 {
+	unsigned long untagged_baddr = untagged_addr(vb->baddr);
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
 	unsigned long prev_pfn, this_pfn;
@@ -167,22 +168,22 @@ static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
 	unsigned int offset;
 	int ret;
 
-	offset = vb->baddr & ~PAGE_MASK;
+	offset = untagged_baddr & ~PAGE_MASK;
 	mem->size = PAGE_ALIGN(vb->size + offset);
 	ret = -EINVAL;
 
 	down_read(&mm->mmap_sem);
 
-	vma = find_vma(mm, vb->baddr);
+	vma = find_vma(mm, untagged_baddr);
 	if (!vma)
 		goto out_up;
 
-	if ((vb->baddr + mem->size) > vma->vm_end)
+	if ((untagged_baddr + mem->size) > vma->vm_end)
 		goto out_up;
 
 	pages_done = 0;
 	prev_pfn = 0; /* kill warning */
-	user_address = vb->baddr;
+	user_address = untagged_baddr;
 
 	while (pages_done < (mem->size >> PAGE_SHIFT)) {
 		ret = follow_pfn(vma, user_address, &this_pfn);
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 13/15] tee/shm, arm64: untag user pointers in tee_shm_register
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (11 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 12/15] media/v4l2-core, arm64: untag user pointers in videobuf_dma_contig_user_get Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 11:43 ` [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn Andrey Konovalov
  2019-06-12 11:43 ` [PATCH v17 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
  14 siblings, 0 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

tee_shm_register()->optee_shm_unregister()->check_mem_type() uses provided
user pointers for vma lookups (via __check_mem_type()), which can only by
done with untagged pointers.

Untag user pointers in this function.

Reviewed-by: Kees Cook <keescook@chromium.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 drivers/tee/tee_shm.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c
index 2da026fd12c9..09ddcd06c715 100644
--- a/drivers/tee/tee_shm.c
+++ b/drivers/tee/tee_shm.c
@@ -254,6 +254,7 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr,
 	shm->teedev = teedev;
 	shm->ctx = ctx;
 	shm->id = -1;
+	addr = untagged_addr(addr);
 	start = rounddown(addr, PAGE_SIZE);
 	shm->offset = addr - start;
 	shm->size = length;
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (12 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 13/15] tee/shm, arm64: untag user pointers in tee_shm_register Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 14:41   ` Vincenzo Frascino
  2019-06-12 15:58   ` Auger Eric
  2019-06-12 11:43 ` [PATCH v17 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
  14 siblings, 2 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

vaddr_get_pfn() uses provided user pointers for vma lookups, which can
only by done with untagged pointers.

Untag user pointers in this function.

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 drivers/vfio/vfio_iommu_type1.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 3ddc375e7063..528e39a1c2dd 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -384,6 +384,8 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
 
 	down_read(&mm->mmap_sem);
 
+	vaddr = untagged_addr(vaddr);
+
 	vma = find_vma_intersection(mm, vaddr, vaddr + 1);
 
 	if (vma && vma->vm_flags & VM_PFNMAP) {
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* [PATCH v17 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel
  2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
                   ` (13 preceding siblings ...)
  2019-06-12 11:43 ` [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn Andrey Konovalov
@ 2019-06-12 11:43 ` Andrey Konovalov
  2019-06-12 12:30   ` Szabolcs Nagy
  14 siblings, 1 reply; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-12 11:43 UTC (permalink / raw)
  To: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy, Andrey Konovalov

This patch is a part of a series that extends arm64 kernel ABI to allow to
pass tagged user pointers (with the top byte set to something else other
than 0x00) as syscall arguments.

This patch adds a simple test, that calls the uname syscall with a
tagged user pointer as an argument. Without the kernel accepting tagged
user pointers the test fails with EFAULT.

Co-developed-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 tools/testing/selftests/arm64/.gitignore      |  2 +
 tools/testing/selftests/arm64/Makefile        | 22 +++++++
 .../testing/selftests/arm64/run_tags_test.sh  | 12 ++++
 tools/testing/selftests/arm64/tags_lib.c      | 62 +++++++++++++++++++
 tools/testing/selftests/arm64/tags_test.c     | 18 ++++++
 5 files changed, 116 insertions(+)
 create mode 100644 tools/testing/selftests/arm64/.gitignore
 create mode 100644 tools/testing/selftests/arm64/Makefile
 create mode 100755 tools/testing/selftests/arm64/run_tags_test.sh
 create mode 100644 tools/testing/selftests/arm64/tags_lib.c
 create mode 100644 tools/testing/selftests/arm64/tags_test.c

diff --git a/tools/testing/selftests/arm64/.gitignore b/tools/testing/selftests/arm64/.gitignore
new file mode 100644
index 000000000000..9b6a568de17f
--- /dev/null
+++ b/tools/testing/selftests/arm64/.gitignore
@@ -0,0 +1,2 @@
+tags_test
+tags_lib.so
diff --git a/tools/testing/selftests/arm64/Makefile b/tools/testing/selftests/arm64/Makefile
new file mode 100644
index 000000000000..9dee18727923
--- /dev/null
+++ b/tools/testing/selftests/arm64/Makefile
@@ -0,0 +1,22 @@
+# SPDX-License-Identifier: GPL-2.0
+
+include ../lib.mk
+
+# ARCH can be overridden by the user for cross compiling
+ARCH ?= $(shell uname -m 2>/dev/null || echo not)
+
+ifneq (,$(filter $(ARCH),aarch64 arm64))
+
+TEST_CUSTOM_PROGS := $(OUTPUT)/tags_test
+
+$(OUTPUT)/tags_test: tags_test.c $(OUTPUT)/tags_lib.so
+	$(CC) -o $@ $(CFLAGS) $(LDFLAGS) $<
+
+$(OUTPUT)/tags_lib.so: tags_lib.c
+	$(CC) -o $@ -shared $(CFLAGS) $(LDFLAGS) $^
+
+TEST_PROGS := run_tags_test.sh
+
+all: $(TEST_CUSTOM_PROGS)
+
+endif
diff --git a/tools/testing/selftests/arm64/run_tags_test.sh b/tools/testing/selftests/arm64/run_tags_test.sh
new file mode 100755
index 000000000000..2bbe0cd4220b
--- /dev/null
+++ b/tools/testing/selftests/arm64/run_tags_test.sh
@@ -0,0 +1,12 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+
+echo "--------------------"
+echo "running tags test"
+echo "--------------------"
+LD_PRELOAD=./tags_lib.so ./tags_test
+if [ $? -ne 0 ]; then
+	echo "[FAIL]"
+else
+	echo "[PASS]"
+fi
diff --git a/tools/testing/selftests/arm64/tags_lib.c b/tools/testing/selftests/arm64/tags_lib.c
new file mode 100644
index 000000000000..55f64fc1aae6
--- /dev/null
+++ b/tools/testing/selftests/arm64/tags_lib.c
@@ -0,0 +1,62 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdlib.h>
+#include <sys/prctl.h>
+
+#define TAG_SHIFT	(56)
+#define TAG_MASK	(0xffUL << TAG_SHIFT)
+
+#define PR_SET_TAGGED_ADDR_CTRL	55
+#define PR_GET_TAGGED_ADDR_CTRL	56
+#define PR_TAGGED_ADDR_ENABLE	(1UL << 0)
+
+void *__libc_malloc(size_t size);
+void __libc_free(void *ptr);
+void *__libc_realloc(void *ptr, size_t size);
+void *__libc_calloc(size_t nmemb, size_t size);
+
+static void *tag_ptr(void *ptr)
+{
+	static int tagged_addr_err = 1;
+	unsigned long tag = 0;
+
+	/*
+	 * Note that this code is racy. We only use it as a part of a single
+	 * threaded test application. Beware of using in multithreaded ones.
+	 */
+	if (tagged_addr_err == 1)
+		tagged_addr_err = prctl(PR_SET_TAGGED_ADDR_CTRL,
+				PR_TAGGED_ADDR_ENABLE, 0, 0, 0);
+
+	if (!ptr)
+		return ptr;
+	if (!tagged_addr_err)
+		tag = rand() & 0xff;
+
+	return (void *)((unsigned long)ptr | (tag << TAG_SHIFT));
+}
+
+static void *untag_ptr(void *ptr)
+{
+	return (void *)((unsigned long)ptr & ~TAG_MASK);
+}
+
+void *malloc(size_t size)
+{
+	return tag_ptr(__libc_malloc(size));
+}
+
+void free(void *ptr)
+{
+	__libc_free(untag_ptr(ptr));
+}
+
+void *realloc(void *ptr, size_t size)
+{
+	return tag_ptr(__libc_realloc(untag_ptr(ptr), size));
+}
+
+void *calloc(size_t nmemb, size_t size)
+{
+	return tag_ptr(__libc_calloc(nmemb, size));
+}
diff --git a/tools/testing/selftests/arm64/tags_test.c b/tools/testing/selftests/arm64/tags_test.c
new file mode 100644
index 000000000000..263b302874ed
--- /dev/null
+++ b/tools/testing/selftests/arm64/tags_test.c
@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdint.h>
+#include <sys/utsname.h>
+
+int main(void)
+{
+	struct utsname *ptr;
+	int err;
+
+	ptr = (struct utsname *)malloc(sizeof(*ptr));
+	err = uname(ptr);
+	free(ptr);
+	return err;
+}
-- 
2.22.0.rc2.383.gf4fbbf30c2-goog


^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel
  2019-06-12 11:43 ` [PATCH v17 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
@ 2019-06-12 12:30   ` Szabolcs Nagy
  0 siblings, 0 replies; 51+ messages in thread
From: Szabolcs Nagy @ 2019-06-12 12:30 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: nd, Catalin Marinas, Vincenzo Frascino, Will Deacon,
	Mark Rutland, Andrew Morton, Greg Kroah-Hartman, Kees Cook,
	Yishai Hadas, Felix Kuehling, Alexander Deucher,
	Christian Koenig, Mauro Carvalho Chehab, Jens Wiklander,
	Alex Williamson, Leon Romanovsky, Luc Van Oostenryck,
	Dave P Martin, Khalid Aziz, enh, Jason Gunthorpe,
	Christoph Hellwig, Dmitry Vyukov, Kostya Serebryany,
	Evgeniy Stepanov, Lee Smith, Ramana Radhakrishnan, Jacob Bramley,
	Ruben Ayrapetyan, Robin Murphy, Kevin Brodsky

On 12/06/2019 12:43, Andrey Konovalov wrote:
> --- /dev/null
> +++ b/tools/testing/selftests/arm64/tags_lib.c
> @@ -0,0 +1,62 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#include <stdlib.h>
> +#include <sys/prctl.h>
> +
> +#define TAG_SHIFT	(56)
> +#define TAG_MASK	(0xffUL << TAG_SHIFT)
> +
> +#define PR_SET_TAGGED_ADDR_CTRL	55
> +#define PR_GET_TAGGED_ADDR_CTRL	56
> +#define PR_TAGGED_ADDR_ENABLE	(1UL << 0)
> +
> +void *__libc_malloc(size_t size);
> +void __libc_free(void *ptr);
> +void *__libc_realloc(void *ptr, size_t size);
> +void *__libc_calloc(size_t nmemb, size_t size);

this does not work on at least musl.

the most robust solution would be to implement
the malloc apis with mmap/munmap/mremap, if that's
too cumbersome then use dlsym RTLD_NEXT (although
that has the slight wart that in glibc it may call
calloc so wrapping calloc that way is tricky).

in simple linux tests i'd just use static or
stack allocations or mmap.

if a generic preloadable lib solution is needed
then do it properly with pthread_once to avoid
races etc.

> +
> +static void *tag_ptr(void *ptr)
> +{
> +	static int tagged_addr_err = 1;
> +	unsigned long tag = 0;
> +
> +	/*
> +	 * Note that this code is racy. We only use it as a part of a single
> +	 * threaded test application. Beware of using in multithreaded ones.
> +	 */
> +	if (tagged_addr_err == 1)
> +		tagged_addr_err = prctl(PR_SET_TAGGED_ADDR_CTRL,
> +				PR_TAGGED_ADDR_ENABLE, 0, 0, 0);
> +
> +	if (!ptr)
> +		return ptr;
> +	if (!tagged_addr_err)
> +		tag = rand() & 0xff;
> +
> +	return (void *)((unsigned long)ptr | (tag << TAG_SHIFT));
> +}
> +
> +static void *untag_ptr(void *ptr)
> +{
> +	return (void *)((unsigned long)ptr & ~TAG_MASK);
> +}
> +
> +void *malloc(size_t size)
> +{
> +	return tag_ptr(__libc_malloc(size));
> +}
...

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr
  2019-06-12 11:43 ` [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
@ 2019-06-12 14:26   ` Vincenzo Frascino
  0 siblings, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-12 14:26 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, Khalid Aziz, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 12/06/2019 12:43, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> copy_from_user (and a few other similar functions) are used to copy data
> from user memory into the kernel memory or vice versa. Since a user can
> provided a tagged pointer to one of the syscalls that use copy_from_user,
> we need to correctly handle such pointers.
> 
> Do this by untagging user pointers in access_ok and in __uaccess_mask_ptr,
> before performing access validity checks.
> 
> Note, that this patch only temporarily untags the pointers to perform the
> checks, but then passes them as is into the kernel internals.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  arch/arm64/include/asm/uaccess.h | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
> index e5d5f31c6d36..df729afca0ba 100644
> --- a/arch/arm64/include/asm/uaccess.h
> +++ b/arch/arm64/include/asm/uaccess.h
> @@ -73,6 +73,8 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si
>  {
>  	unsigned long ret, limit = current_thread_info()->addr_limit;
>  
> +	addr = untagged_addr(addr);
> +
>  	__chk_user_ptr(addr);
>  	asm volatile(
>  	// A + B <= C + 1 for all A,B,C, in four easy steps:
> @@ -226,7 +228,8 @@ static inline void uaccess_enable_not_uao(void)
>  
>  /*
>   * Sanitise a uaccess pointer such that it becomes NULL if above the
> - * current addr_limit.
> + * current addr_limit. In case the pointer is tagged (has the top byte set),
> + * untag the pointer before checking.
>   */
>  #define uaccess_mask_ptr(ptr) (__typeof__(ptr))__uaccess_mask_ptr(ptr)
>  static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
> @@ -234,10 +237,11 @@ static inline void __user *__uaccess_mask_ptr(const void __user *ptr)
>  	void __user *safe_ptr;
>  
>  	asm volatile(
> -	"	bics	xzr, %1, %2\n"
> +	"	bics	xzr, %3, %2\n"
>  	"	csel	%0, %1, xzr, eq\n"
>  	: "=&r" (safe_ptr)
> -	: "r" (ptr), "r" (current_thread_info()->addr_limit)
> +	: "r" (ptr), "r" (current_thread_info()->addr_limit),
> +	  "r" (untagged_addr(ptr))
>  	: "cc");
>  
>  	csdb();
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 02/15] lib, arm64: untag user pointers in strn*_user
  2019-06-12 11:43 ` [PATCH v17 02/15] lib, arm64: untag user pointers in strn*_user Andrey Konovalov
@ 2019-06-12 14:28   ` Vincenzo Frascino
  0 siblings, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-12 14:28 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, Khalid Aziz, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 12/06/2019 12:43, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> strncpy_from_user and strnlen_user accept user addresses as arguments, and
> do not go through the same path as copy_from_user and others, so here we
> need to handle the case of tagged user addresses separately.
> 
> Untag user pointers passed to these functions.
> 
> Note, that this patch only temporarily untags the pointers to perform
> validity checks, but then uses them as is to perform user memory accesses.
> 
> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
> Acked-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  lib/strncpy_from_user.c | 3 ++-
>  lib/strnlen_user.c      | 3 ++-
>  2 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/strncpy_from_user.c b/lib/strncpy_from_user.c
> index 023ba9f3b99f..dccb95af6003 100644
> --- a/lib/strncpy_from_user.c
> +++ b/lib/strncpy_from_user.c
> @@ -6,6 +6,7 @@
>  #include <linux/uaccess.h>
>  #include <linux/kernel.h>
>  #include <linux/errno.h>
> +#include <linux/mm.h>
>  
>  #include <asm/byteorder.h>
>  #include <asm/word-at-a-time.h>
> @@ -108,7 +109,7 @@ long strncpy_from_user(char *dst, const char __user *src, long count)
>  		return 0;
>  
>  	max_addr = user_addr_max();
> -	src_addr = (unsigned long)src;
> +	src_addr = (unsigned long)untagged_addr(src);
>  	if (likely(src_addr < max_addr)) {
>  		unsigned long max = max_addr - src_addr;
>  		long retval;
> diff --git a/lib/strnlen_user.c b/lib/strnlen_user.c
> index 7f2db3fe311f..28ff554a1be8 100644
> --- a/lib/strnlen_user.c
> +++ b/lib/strnlen_user.c
> @@ -2,6 +2,7 @@
>  #include <linux/kernel.h>
>  #include <linux/export.h>
>  #include <linux/uaccess.h>
> +#include <linux/mm.h>
>  
>  #include <asm/word-at-a-time.h>
>  
> @@ -109,7 +110,7 @@ long strnlen_user(const char __user *str, long count)
>  		return 0;
>  
>  	max_addr = user_addr_max();
> -	src_addr = (unsigned long)str;
> +	src_addr = (unsigned long)untagged_addr(str);
>  	if (likely(src_addr < max_addr)) {
>  		unsigned long max = max_addr - src_addr;
>  		long retval;
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
@ 2019-06-12 14:30   ` Vincenzo Frascino
  2019-06-12 14:55   ` Catalin Marinas
                     ` (4 subsequent siblings)
  5 siblings, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-12 14:30 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, Khalid Aziz, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 12/06/2019 12:43, Andrey Konovalov wrote:
> From: Catalin Marinas <catalin.marinas@arm.com>
> 
> It is not desirable to relax the ABI to allow tagged user addresses into
> the kernel indiscriminately. This patch introduces a prctl() interface
> for enabling or disabling the tagged ABI with a global sysctl control
> for preventing applications from enabling the relaxed ABI (meant for
> testing user-space prctl() return error checking without reconfiguring
> the kernel). The ABI properties are inherited by threads of the same
> application and fork()'ed children but cleared on execve().
> 
> The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> MTE-specific settings like imprecise vs precise exceptions.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  arch/arm64/include/asm/processor.h   |  6 +++
>  arch/arm64/include/asm/thread_info.h |  1 +
>  arch/arm64/include/asm/uaccess.h     |  3 +-
>  arch/arm64/kernel/process.c          | 67 ++++++++++++++++++++++++++++
>  include/uapi/linux/prctl.h           |  5 +++
>  kernel/sys.c                         | 16 +++++++
>  6 files changed, 97 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> index fcd0e691b1ea..fee457456aa8 100644
> --- a/arch/arm64/include/asm/processor.h
> +++ b/arch/arm64/include/asm/processor.h
> @@ -307,6 +307,12 @@ extern void __init minsigstksz_setup(void);
>  /* PR_PAC_RESET_KEYS prctl */
>  #define PAC_RESET_KEYS(tsk, arg)	ptrauth_prctl_reset_keys(tsk, arg)
>  
> +/* PR_TAGGED_ADDR prctl */
> +long set_tagged_addr_ctrl(unsigned long arg);
> +long get_tagged_addr_ctrl(void);
> +#define SET_TAGGED_ADDR_CTRL(arg)	set_tagged_addr_ctrl(arg)
> +#define GET_TAGGED_ADDR_CTRL()		get_tagged_addr_ctrl()
> +
>  /*
>   * For CONFIG_GCC_PLUGIN_STACKLEAK
>   *
> diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
> index f1d032be628a..354a31d2b737 100644
> --- a/arch/arm64/include/asm/thread_info.h
> +++ b/arch/arm64/include/asm/thread_info.h
> @@ -99,6 +99,7 @@ void arch_release_task_struct(struct task_struct *tsk);
>  #define TIF_SVE			23	/* Scalable Vector Extension in use */
>  #define TIF_SVE_VL_INHERIT	24	/* Inherit sve_vl_onexec across exec */
>  #define TIF_SSBD		25	/* Wants SSB mitigation */
> +#define TIF_TAGGED_ADDR		26	/* Allow tagged user addresses */
>  
>  #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
>  #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
> index df729afca0ba..995b9ea11a89 100644
> --- a/arch/arm64/include/asm/uaccess.h
> +++ b/arch/arm64/include/asm/uaccess.h
> @@ -73,7 +73,8 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si
>  {
>  	unsigned long ret, limit = current_thread_info()->addr_limit;
>  
> -	addr = untagged_addr(addr);
> +	if (test_thread_flag(TIF_TAGGED_ADDR))
> +		addr = untagged_addr(addr);
>  
>  	__chk_user_ptr(addr);
>  	asm volatile(
> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index 3767fb21a5b8..69d0be1fc708 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -30,6 +30,7 @@
>  #include <linux/kernel.h>
>  #include <linux/mm.h>
>  #include <linux/stddef.h>
> +#include <linux/sysctl.h>
>  #include <linux/unistd.h>
>  #include <linux/user.h>
>  #include <linux/delay.h>
> @@ -323,6 +324,7 @@ void flush_thread(void)
>  	fpsimd_flush_thread();
>  	tls_thread_flush();
>  	flush_ptrace_hw_breakpoint(current);
> +	clear_thread_flag(TIF_TAGGED_ADDR);
>  }
>  
>  void release_thread(struct task_struct *dead_task)
> @@ -552,3 +554,68 @@ void arch_setup_new_exec(void)
>  
>  	ptrauth_thread_init_user(current);
>  }
> +
> +/*
> + * Control the relaxed ABI allowing tagged user addresses into the kernel.
> + */
> +static unsigned int tagged_addr_prctl_allowed = 1;
> +
> +long set_tagged_addr_ctrl(unsigned long arg)
> +{
> +	if (!tagged_addr_prctl_allowed)
> +		return -EINVAL;
> +	if (is_compat_task())
> +		return -EINVAL;
> +	if (arg & ~PR_TAGGED_ADDR_ENABLE)
> +		return -EINVAL;
> +
> +	if (arg & PR_TAGGED_ADDR_ENABLE)
> +		set_thread_flag(TIF_TAGGED_ADDR);
> +	else
> +		clear_thread_flag(TIF_TAGGED_ADDR);
> +
> +	return 0;
> +}
> +
> +long get_tagged_addr_ctrl(void)
> +{
> +	if (!tagged_addr_prctl_allowed)
> +		return -EINVAL;
> +	if (is_compat_task())
> +		return -EINVAL;
> +
> +	if (test_thread_flag(TIF_TAGGED_ADDR))
> +		return PR_TAGGED_ADDR_ENABLE;
> +
> +	return 0;
> +}
> +
> +/*
> + * Global sysctl to disable the tagged user addresses support. This control
> + * only prevents the tagged address ABI enabling via prctl() and does not
> + * disable it for tasks that already opted in to the relaxed ABI.
> + */
> +static int zero;
> +static int one = 1;
> +
> +static struct ctl_table tagged_addr_sysctl_table[] = {
> +	{
> +		.procname	= "tagged_addr",
> +		.mode		= 0644,
> +		.data		= &tagged_addr_prctl_allowed,
> +		.maxlen		= sizeof(int),
> +		.proc_handler	= proc_dointvec_minmax,
> +		.extra1		= &zero,
> +		.extra2		= &one,
> +	},
> +	{ }
> +};
> +
> +static int __init tagged_addr_init(void)
> +{
> +	if (!register_sysctl("abi", tagged_addr_sysctl_table))
> +		return -EINVAL;
> +	return 0;
> +}
> +
> +core_initcall(tagged_addr_init);
> diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
> index 094bb03b9cc2..2e927b3e9d6c 100644
> --- a/include/uapi/linux/prctl.h
> +++ b/include/uapi/linux/prctl.h
> @@ -229,4 +229,9 @@ struct prctl_mm_map {
>  # define PR_PAC_APDBKEY			(1UL << 3)
>  # define PR_PAC_APGAKEY			(1UL << 4)
>  
> +/* Tagged user address controls for arm64 */
> +#define PR_SET_TAGGED_ADDR_CTRL		55
> +#define PR_GET_TAGGED_ADDR_CTRL		56
> +# define PR_TAGGED_ADDR_ENABLE		(1UL << 0)
> +
>  #endif /* _LINUX_PRCTL_H */
> diff --git a/kernel/sys.c b/kernel/sys.c
> index 2969304c29fe..ec48396b4943 100644
> --- a/kernel/sys.c
> +++ b/kernel/sys.c
> @@ -124,6 +124,12 @@
>  #ifndef PAC_RESET_KEYS
>  # define PAC_RESET_KEYS(a, b)	(-EINVAL)
>  #endif
> +#ifndef SET_TAGGED_ADDR_CTRL
> +# define SET_TAGGED_ADDR_CTRL(a)	(-EINVAL)
> +#endif
> +#ifndef GET_TAGGED_ADDR_CTRL
> +# define GET_TAGGED_ADDR_CTRL()		(-EINVAL)
> +#endif
>  
>  /*
>   * this is where the system-wide overflow UID and GID are defined, for
> @@ -2492,6 +2498,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
>  			return -EINVAL;
>  		error = PAC_RESET_KEYS(me, arg2);
>  		break;
> +	case PR_SET_TAGGED_ADDR_CTRL:
> +		if (arg3 || arg4 || arg5)
> +			return -EINVAL;
> +		error = SET_TAGGED_ADDR_CTRL(arg2);
> +		break;
> +	case PR_GET_TAGGED_ADDR_CTRL:
> +		if (arg2 || arg3 || arg4 || arg5)
> +			return -EINVAL;
> +		error = GET_TAGGED_ADDR_CTRL();
> +		break;
>  	default:
>  		error = -EINVAL;
>  		break;
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls
  2019-06-12 11:43 ` [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov
@ 2019-06-12 14:31   ` Vincenzo Frascino
  2019-06-19 15:55   ` Khalid Aziz
  1 sibling, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-12 14:31 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, Khalid Aziz, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 12/06/2019 12:43, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> This patch allows tagged pointers to be passed to the following memory
> syscalls: get_mempolicy, madvise, mbind, mincore, mlock, mlock2, mprotect,
> mremap, msync, munlock, move_pages.
> 
> The mmap and mremap syscalls do not currently accept tagged addresses.
> Architectures may interpret the tag as a background colour for the
> corresponding vma.
> 
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  mm/madvise.c   | 2 ++
>  mm/mempolicy.c | 3 +++
>  mm/migrate.c   | 2 +-
>  mm/mincore.c   | 2 ++
>  mm/mlock.c     | 4 ++++
>  mm/mprotect.c  | 2 ++
>  mm/mremap.c    | 7 +++++++
>  mm/msync.c     | 2 ++
>  8 files changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 628022e674a7..39b82f8a698f 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -810,6 +810,8 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
>  	size_t len;
>  	struct blk_plug plug;
>  
> +	start = untagged_addr(start);
> +
>  	if (!madvise_behavior_valid(behavior))
>  		return error;
>  
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 01600d80ae01..78e0a88b2680 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1360,6 +1360,7 @@ static long kernel_mbind(unsigned long start, unsigned long len,
>  	int err;
>  	unsigned short mode_flags;
>  
> +	start = untagged_addr(start);
>  	mode_flags = mode & MPOL_MODE_FLAGS;
>  	mode &= ~MPOL_MODE_FLAGS;
>  	if (mode >= MPOL_MAX)
> @@ -1517,6 +1518,8 @@ static int kernel_get_mempolicy(int __user *policy,
>  	int uninitialized_var(pval);
>  	nodemask_t nodes;
>  
> +	addr = untagged_addr(addr);
> +
>  	if (nmask != NULL && maxnode < nr_node_ids)
>  		return -EINVAL;
>  
> diff --git a/mm/migrate.c b/mm/migrate.c
> index f2ecc2855a12..d22c45cf36b2 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1616,7 +1616,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>  			goto out_flush;
>  		if (get_user(node, nodes + i))
>  			goto out_flush;
> -		addr = (unsigned long)p;
> +		addr = (unsigned long)untagged_addr(p);
>  
>  		err = -ENODEV;
>  		if (node < 0 || node >= MAX_NUMNODES)
> diff --git a/mm/mincore.c b/mm/mincore.c
> index c3f058bd0faf..64c322ed845c 100644
> --- a/mm/mincore.c
> +++ b/mm/mincore.c
> @@ -249,6 +249,8 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
>  	unsigned long pages;
>  	unsigned char *tmp;
>  
> +	start = untagged_addr(start);
> +
>  	/* Check the start address: needs to be page-aligned.. */
>  	if (start & ~PAGE_MASK)
>  		return -EINVAL;
> diff --git a/mm/mlock.c b/mm/mlock.c
> index 080f3b36415b..e82609eaa428 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -674,6 +674,8 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla
>  	unsigned long lock_limit;
>  	int error = -ENOMEM;
>  
> +	start = untagged_addr(start);
> +
>  	if (!can_do_mlock())
>  		return -EPERM;
>  
> @@ -735,6 +737,8 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
>  {
>  	int ret;
>  
> +	start = untagged_addr(start);
> +
>  	len = PAGE_ALIGN(len + (offset_in_page(start)));
>  	start &= PAGE_MASK;
>  
> diff --git a/mm/mprotect.c b/mm/mprotect.c
> index bf38dfbbb4b4..19f981b733bc 100644
> --- a/mm/mprotect.c
> +++ b/mm/mprotect.c
> @@ -465,6 +465,8 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
>  	const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
>  				(prot & PROT_READ);
>  
> +	start = untagged_addr(start);
> +
>  	prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
>  	if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
>  		return -EINVAL;
> diff --git a/mm/mremap.c b/mm/mremap.c
> index fc241d23cd97..64c9a3b8be0a 100644
> --- a/mm/mremap.c
> +++ b/mm/mremap.c
> @@ -606,6 +606,13 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
>  	LIST_HEAD(uf_unmap_early);
>  	LIST_HEAD(uf_unmap);
>  
> +	/*
> +	 * Architectures may interpret the tag passed to mmap as a background
> +	 * colour for the corresponding vma. For mremap we don't allow tagged
> +	 * new_addr to preserve similar behaviour to mmap.
> +	 */
> +	addr = untagged_addr(addr);
> +
>  	if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
>  		return ret;
>  
> diff --git a/mm/msync.c b/mm/msync.c
> index ef30a429623a..c3bd3e75f687 100644
> --- a/mm/msync.c
> +++ b/mm/msync.c
> @@ -37,6 +37,8 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
>  	int unmapped_error = 0;
>  	int error = -EINVAL;
>  
> +	start = untagged_addr(start);
> +
>  	if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
>  		goto out;
>  	if (offset_in_page(start))
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c
  2019-06-12 11:43 ` [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
@ 2019-06-12 14:33   ` Vincenzo Frascino
  2019-06-19 16:41   ` Khalid Aziz
  1 sibling, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-12 14:33 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, Khalid Aziz, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 12/06/2019 12:43, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> mm/gup.c provides a kernel interface that accepts user addresses and
> manipulates user pages directly (for example get_user_pages, that is used
> by the futex syscall). Since a user can provided tagged addresses, we need
> to handle this case.
> 
> Add untagging to gup.c functions that use user addresses for vma lookups.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  mm/gup.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index ddde097cf9e4..c37df3d455a2 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -802,6 +802,8 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
>  	if (!nr_pages)
>  		return 0;
>  
> +	start = untagged_addr(start);
> +
>  	VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
>  
>  	/*
> @@ -964,6 +966,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
>  	struct vm_area_struct *vma;
>  	vm_fault_t ret, major = 0;
>  
> +	address = untagged_addr(address);
> +
>  	if (unlocked)
>  		fault_flags |= FAULT_FLAG_ALLOW_RETRY;
>  
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames
  2019-06-12 11:43 ` [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames Andrey Konovalov
@ 2019-06-12 14:34   ` Vincenzo Frascino
  2019-06-19 16:48   ` Khalid Aziz
  1 sibling, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-12 14:34 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, Khalid Aziz, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 12/06/2019 12:43, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> get_vaddr_frames uses provided user pointers for vma lookups, which can
> only by done with untagged pointers. Instead of locating and changing
> all callers of this function, perform untagging in it.
> 
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  mm/frame_vector.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/frame_vector.c b/mm/frame_vector.c
> index c64dca6e27c2..c431ca81dad5 100644
> --- a/mm/frame_vector.c
> +++ b/mm/frame_vector.c
> @@ -46,6 +46,8 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
>  	if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
>  		nr_frames = vec->nr_allocated;
>  
> +	start = untagged_addr(start);
> +
>  	down_read(&mm->mmap_sem);
>  	locked = 1;
>  	vma = find_vma_intersection(mm, start, start + 1);
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options
  2019-06-12 11:43 ` [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
@ 2019-06-12 14:35   ` Vincenzo Frascino
  2019-06-19 20:01   ` Khalid Aziz
  1 sibling, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-12 14:35 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, Khalid Aziz, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 12/06/2019 12:43, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> In copy_mount_options a user address is being subtracted from TASK_SIZE.
> If the address is lower than TASK_SIZE, the size is calculated to not
> allow the exact_copy_from_user() call to cross TASK_SIZE boundary.
> However if the address is tagged, then the size will be calculated
> incorrectly.
> 
> Untag the address before subtracting.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  fs/namespace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/namespace.c b/fs/namespace.c
> index b26778bdc236..2e85712a19ed 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -2993,7 +2993,7 @@ void *copy_mount_options(const void __user * data)
>  	 * the remainder of the page.
>  	 */
>  	/* copy_from_user cannot cross TASK_SIZE ! */
> -	size = TASK_SIZE - (unsigned long)data;
> +	size = TASK_SIZE - (unsigned long)untagged_addr(data);
>  	if (size > PAGE_SIZE)
>  		size = PAGE_SIZE;
>  
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 08/15] userfaultfd, arm64: untag user pointers
  2019-06-12 11:43 ` [PATCH v17 08/15] userfaultfd, arm64: untag user pointers Andrey Konovalov
@ 2019-06-12 14:40   ` Vincenzo Frascino
  0 siblings, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-12 14:40 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, Khalid Aziz, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 12/06/2019 12:43, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> userfaultfd code use provided user pointers for vma lookups, which can
> only by done with untagged pointers.
> 
> Untag user pointers in validate_range().
> 
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  fs/userfaultfd.c | 22 ++++++++++++----------
>  1 file changed, 12 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
> index 3b30301c90ec..24d68c3b5ee2 100644
> --- a/fs/userfaultfd.c
> +++ b/fs/userfaultfd.c
> @@ -1263,21 +1263,23 @@ static __always_inline void wake_userfault(struct userfaultfd_ctx *ctx,
>  }
>  
>  static __always_inline int validate_range(struct mm_struct *mm,
> -					  __u64 start, __u64 len)
> +					  __u64 *start, __u64 len)
>  {
>  	__u64 task_size = mm->task_size;
>  
> -	if (start & ~PAGE_MASK)
> +	*start = untagged_addr(*start);
> +
> +	if (*start & ~PAGE_MASK)
>  		return -EINVAL;
>  	if (len & ~PAGE_MASK)
>  		return -EINVAL;
>  	if (!len)
>  		return -EINVAL;
> -	if (start < mmap_min_addr)
> +	if (*start < mmap_min_addr)
>  		return -EINVAL;
> -	if (start >= task_size)
> +	if (*start >= task_size)
>  		return -EINVAL;
> -	if (len > task_size - start)
> +	if (len > task_size - *start)
>  		return -EINVAL;
>  	return 0;
>  }
> @@ -1327,7 +1329,7 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
>  		goto out;
>  	}
>  
> -	ret = validate_range(mm, uffdio_register.range.start,
> +	ret = validate_range(mm, &uffdio_register.range.start,
>  			     uffdio_register.range.len);
>  	if (ret)
>  		goto out;
> @@ -1516,7 +1518,7 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
>  	if (copy_from_user(&uffdio_unregister, buf, sizeof(uffdio_unregister)))
>  		goto out;
>  
> -	ret = validate_range(mm, uffdio_unregister.start,
> +	ret = validate_range(mm, &uffdio_unregister.start,
>  			     uffdio_unregister.len);
>  	if (ret)
>  		goto out;
> @@ -1667,7 +1669,7 @@ static int userfaultfd_wake(struct userfaultfd_ctx *ctx,
>  	if (copy_from_user(&uffdio_wake, buf, sizeof(uffdio_wake)))
>  		goto out;
>  
> -	ret = validate_range(ctx->mm, uffdio_wake.start, uffdio_wake.len);
> +	ret = validate_range(ctx->mm, &uffdio_wake.start, uffdio_wake.len);
>  	if (ret)
>  		goto out;
>  
> @@ -1707,7 +1709,7 @@ static int userfaultfd_copy(struct userfaultfd_ctx *ctx,
>  			   sizeof(uffdio_copy)-sizeof(__s64)))
>  		goto out;
>  
> -	ret = validate_range(ctx->mm, uffdio_copy.dst, uffdio_copy.len);
> +	ret = validate_range(ctx->mm, &uffdio_copy.dst, uffdio_copy.len);
>  	if (ret)
>  		goto out;
>  	/*
> @@ -1763,7 +1765,7 @@ static int userfaultfd_zeropage(struct userfaultfd_ctx *ctx,
>  			   sizeof(uffdio_zeropage)-sizeof(__s64)))
>  		goto out;
>  
> -	ret = validate_range(ctx->mm, uffdio_zeropage.range.start,
> +	ret = validate_range(ctx->mm, &uffdio_zeropage.range.start,
>  			     uffdio_zeropage.range.len);
>  	if (ret)
>  		goto out;
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn
  2019-06-12 11:43 ` [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn Andrey Konovalov
@ 2019-06-12 14:41   ` Vincenzo Frascino
  2019-06-12 15:58   ` Auger Eric
  1 sibling, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-12 14:41 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, Khalid Aziz, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 12/06/2019 12:43, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> vaddr_get_pfn() uses provided user pointers for vma lookups, which can
> only by done with untagged pointers.
> 
> Untag user pointers in this function.
> 
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>

Reviewed-by: Vincenzo Frascino <vincenzo.frascino@arm.com>

> ---
>  drivers/vfio/vfio_iommu_type1.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 3ddc375e7063..528e39a1c2dd 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -384,6 +384,8 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
>  
>  	down_read(&mm->mmap_sem);
>  
> +	vaddr = untagged_addr(vaddr);
> +
>  	vma = find_vma_intersection(mm, vaddr, vaddr + 1);
>  
>  	if (vma && vma->vm_flags & VM_PFNMAP) {
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
  2019-06-12 14:30   ` Vincenzo Frascino
@ 2019-06-12 14:55   ` Catalin Marinas
  2019-06-13 11:02   ` Dave Martin
                     ` (3 subsequent siblings)
  5 siblings, 0 replies; 51+ messages in thread
From: Catalin Marinas @ 2019-06-12 14:55 UTC (permalink / raw)
  To: Andrey Konovalov
  Cc: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest, Vincenzo Frascino,
	Will Deacon, Mark Rutland, Andrew Morton, Greg Kroah-Hartman,
	Kees Cook, Yishai Hadas, Felix Kuehling, Alexander Deucher,
	Christian Koenig, Mauro Carvalho Chehab, Jens Wiklander,
	Alex Williamson, Leon Romanovsky, Luc Van Oostenryck,
	Dave Martin, Khalid Aziz, enh, Jason Gunthorpe,
	Christoph Hellwig, Dmitry Vyukov, Kostya Serebryany,
	Evgeniy Stepanov, Lee Smith, Ramana Radhakrishnan, Jacob Bramley,
	Ruben Ayrapetyan, Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> From: Catalin Marinas <catalin.marinas@arm.com>
> 
> It is not desirable to relax the ABI to allow tagged user addresses into
> the kernel indiscriminately. This patch introduces a prctl() interface
> for enabling or disabling the tagged ABI with a global sysctl control
> for preventing applications from enabling the relaxed ABI (meant for
> testing user-space prctl() return error checking without reconfiguring
> the kernel). The ABI properties are inherited by threads of the same
> application and fork()'ed children but cleared on execve().
> 
> The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> MTE-specific settings like imprecise vs precise exceptions.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

You need your signed-off-by here since you are contributing it. And
thanks for adding the comment to the TIF definition.

-- 
Catalin

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn
  2019-06-12 11:43 ` [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn Andrey Konovalov
  2019-06-12 14:41   ` Vincenzo Frascino
@ 2019-06-12 15:58   ` Auger Eric
  1 sibling, 0 replies; 51+ messages in thread
From: Auger Eric @ 2019-06-12 15:58 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

Hi Andrey,

On 6/12/19 1:43 PM, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> vaddr_get_pfn() uses provided user pointers for vma lookups, which can
> only by done with untagged pointers.
> 
> Untag user pointers in this function.
> 
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Eric Auger <eric.auger@redhat.com>

Thanks

Eric
> ---
>  drivers/vfio/vfio_iommu_type1.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
> index 3ddc375e7063..528e39a1c2dd 100644
> --- a/drivers/vfio/vfio_iommu_type1.c
> +++ b/drivers/vfio/vfio_iommu_type1.c
> @@ -384,6 +384,8 @@ static int vaddr_get_pfn(struct mm_struct *mm, unsigned long vaddr,
>  
>  	down_read(&mm->mmap_sem);
>  
> +	vaddr = untagged_addr(vaddr);
> +
>  	vma = find_vma_intersection(mm, vaddr, vaddr + 1);
>  
>  	if (vma && vma->vm_flags & VM_PFNMAP) {
> 

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
  2019-06-12 14:30   ` Vincenzo Frascino
  2019-06-12 14:55   ` Catalin Marinas
@ 2019-06-13 11:02   ` Dave Martin
  2019-06-13 15:26     ` Catalin Marinas
  2019-06-13 11:16   ` Dave Martin
                     ` (2 subsequent siblings)
  5 siblings, 1 reply; 51+ messages in thread
From: Dave Martin @ 2019-06-13 11:02 UTC (permalink / raw)
  To: Andrey Konovalov
  Cc: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest, Mark Rutland,
	Szabolcs Nagy, Catalin Marinas, Will Deacon, Kostya Serebryany,
	Khalid Aziz, Felix Kuehling, Vincenzo Frascino, Jacob Bramley,
	Leon Romanovsky, Christoph Hellwig, Jason Gunthorpe,
	Evgeniy Stepanov, Kevin Brodsky, Kees Cook, Ruben Ayrapetyan,
	Ramana Radhakrishnan, Alex Williamson, Mauro Carvalho Chehab,
	Dmitry Vyukov, Greg Kroah-Hartman, Yishai Hadas, Jens Wiklander,
	Lee Smith, Alexander Deucher, Andrew Morton, enh, Robin Murphy,
	Christian Koenig, Luc Van Oostenryck

On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> From: Catalin Marinas <catalin.marinas@arm.com>
> 
> It is not desirable to relax the ABI to allow tagged user addresses into
> the kernel indiscriminately. This patch introduces a prctl() interface
> for enabling or disabling the tagged ABI with a global sysctl control
> for preventing applications from enabling the relaxed ABI (meant for
> testing user-space prctl() return error checking without reconfiguring
> the kernel). The ABI properties are inherited by threads of the same
> application and fork()'ed children but cleared on execve().
> 
> The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> MTE-specific settings like imprecise vs precise exceptions.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> ---
>  arch/arm64/include/asm/processor.h   |  6 +++
>  arch/arm64/include/asm/thread_info.h |  1 +
>  arch/arm64/include/asm/uaccess.h     |  3 +-
>  arch/arm64/kernel/process.c          | 67 ++++++++++++++++++++++++++++
>  include/uapi/linux/prctl.h           |  5 +++
>  kernel/sys.c                         | 16 +++++++
>  6 files changed, 97 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> index fcd0e691b1ea..fee457456aa8 100644
> --- a/arch/arm64/include/asm/processor.h
> +++ b/arch/arm64/include/asm/processor.h
> @@ -307,6 +307,12 @@ extern void __init minsigstksz_setup(void);
>  /* PR_PAC_RESET_KEYS prctl */
>  #define PAC_RESET_KEYS(tsk, arg)	ptrauth_prctl_reset_keys(tsk, arg)
>  
> +/* PR_TAGGED_ADDR prctl */
> +long set_tagged_addr_ctrl(unsigned long arg);
> +long get_tagged_addr_ctrl(void);
> +#define SET_TAGGED_ADDR_CTRL(arg)	set_tagged_addr_ctrl(arg)
> +#define GET_TAGGED_ADDR_CTRL()		get_tagged_addr_ctrl()
> +
>  /*
>   * For CONFIG_GCC_PLUGIN_STACKLEAK
>   *
> diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
> index f1d032be628a..354a31d2b737 100644
> --- a/arch/arm64/include/asm/thread_info.h
> +++ b/arch/arm64/include/asm/thread_info.h
> @@ -99,6 +99,7 @@ void arch_release_task_struct(struct task_struct *tsk);
>  #define TIF_SVE			23	/* Scalable Vector Extension in use */
>  #define TIF_SVE_VL_INHERIT	24	/* Inherit sve_vl_onexec across exec */
>  #define TIF_SSBD		25	/* Wants SSB mitigation */
> +#define TIF_TAGGED_ADDR		26	/* Allow tagged user addresses */
>  
>  #define _TIF_SIGPENDING		(1 << TIF_SIGPENDING)
>  #define _TIF_NEED_RESCHED	(1 << TIF_NEED_RESCHED)
> diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
> index df729afca0ba..995b9ea11a89 100644
> --- a/arch/arm64/include/asm/uaccess.h
> +++ b/arch/arm64/include/asm/uaccess.h
> @@ -73,7 +73,8 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si
>  {
>  	unsigned long ret, limit = current_thread_info()->addr_limit;
>  
> -	addr = untagged_addr(addr);
> +	if (test_thread_flag(TIF_TAGGED_ADDR))
> +		addr = untagged_addr(addr);
>  
>  	__chk_user_ptr(addr);
>  	asm volatile(
> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index 3767fb21a5b8..69d0be1fc708 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -30,6 +30,7 @@
>  #include <linux/kernel.h>
>  #include <linux/mm.h>
>  #include <linux/stddef.h>
> +#include <linux/sysctl.h>
>  #include <linux/unistd.h>
>  #include <linux/user.h>
>  #include <linux/delay.h>
> @@ -323,6 +324,7 @@ void flush_thread(void)
>  	fpsimd_flush_thread();
>  	tls_thread_flush();
>  	flush_ptrace_hw_breakpoint(current);
> +	clear_thread_flag(TIF_TAGGED_ADDR);
>  }
>  
>  void release_thread(struct task_struct *dead_task)
> @@ -552,3 +554,68 @@ void arch_setup_new_exec(void)
>  
>  	ptrauth_thread_init_user(current);
>  }
> +
> +/*
> + * Control the relaxed ABI allowing tagged user addresses into the kernel.
> + */
> +static unsigned int tagged_addr_prctl_allowed = 1;
> +
> +long set_tagged_addr_ctrl(unsigned long arg)
> +{
> +	if (!tagged_addr_prctl_allowed)
> +		return -EINVAL;
> +	if (is_compat_task())
> +		return -EINVAL;
> +	if (arg & ~PR_TAGGED_ADDR_ENABLE)
> +		return -EINVAL;
> +
> +	if (arg & PR_TAGGED_ADDR_ENABLE)
> +		set_thread_flag(TIF_TAGGED_ADDR);
> +	else
> +		clear_thread_flag(TIF_TAGGED_ADDR);
> +
> +	return 0;
> +}
> +
> +long get_tagged_addr_ctrl(void)
> +{
> +	if (!tagged_addr_prctl_allowed)
> +		return -EINVAL;
> +	if (is_compat_task())
> +		return -EINVAL;
> +
> +	if (test_thread_flag(TIF_TAGGED_ADDR))
> +		return PR_TAGGED_ADDR_ENABLE;
> +
> +	return 0;
> +}
> +
> +/*
> + * Global sysctl to disable the tagged user addresses support. This control
> + * only prevents the tagged address ABI enabling via prctl() and does not
> + * disable it for tasks that already opted in to the relaxed ABI.
> + */
> +static int zero;
> +static int one = 1;

!!!

And these can't even be const without a cast.  Yuk.

(Not your fault though, but it would be nice to have a proc_dobool() to
avoid this.)

> +
> +static struct ctl_table tagged_addr_sysctl_table[] = {
> +	{
> +		.procname	= "tagged_addr",
> +		.mode		= 0644,
> +		.data		= &tagged_addr_prctl_allowed,
> +		.maxlen		= sizeof(int),
> +		.proc_handler	= proc_dointvec_minmax,
> +		.extra1		= &zero,
> +		.extra2		= &one,
> +	},
> +	{ }
> +};
> +
> +static int __init tagged_addr_init(void)
> +{
> +	if (!register_sysctl("abi", tagged_addr_sysctl_table))
> +		return -EINVAL;
> +	return 0;
> +}
> +
> +core_initcall(tagged_addr_init);
> diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
> index 094bb03b9cc2..2e927b3e9d6c 100644
> --- a/include/uapi/linux/prctl.h
> +++ b/include/uapi/linux/prctl.h
> @@ -229,4 +229,9 @@ struct prctl_mm_map {
>  # define PR_PAC_APDBKEY			(1UL << 3)
>  # define PR_PAC_APGAKEY			(1UL << 4)
>  
> +/* Tagged user address controls for arm64 */
> +#define PR_SET_TAGGED_ADDR_CTRL		55
> +#define PR_GET_TAGGED_ADDR_CTRL		56
> +# define PR_TAGGED_ADDR_ENABLE		(1UL << 0)
> +

Do we expect this prctl to be applicable to other arches, or is it
strictly arm64-specific?

>  #endif /* _LINUX_PRCTL_H */
> diff --git a/kernel/sys.c b/kernel/sys.c
> index 2969304c29fe..ec48396b4943 100644
> --- a/kernel/sys.c
> +++ b/kernel/sys.c
> @@ -124,6 +124,12 @@
>  #ifndef PAC_RESET_KEYS
>  # define PAC_RESET_KEYS(a, b)	(-EINVAL)
>  #endif
> +#ifndef SET_TAGGED_ADDR_CTRL
> +# define SET_TAGGED_ADDR_CTRL(a)	(-EINVAL)
> +#endif
> +#ifndef GET_TAGGED_ADDR_CTRL
> +# define GET_TAGGED_ADDR_CTRL()		(-EINVAL)
> +#endif
>  
>  /*
>   * this is where the system-wide overflow UID and GID are defined, for
> @@ -2492,6 +2498,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
>  			return -EINVAL;
>  		error = PAC_RESET_KEYS(me, arg2);
>  		break;
> +	case PR_SET_TAGGED_ADDR_CTRL:
> +		if (arg3 || arg4 || arg5)

<bikeshed>

How do you anticipate these arguments being used in the future?

For the SVE prctls I took the view that "get" could only ever mean one
thing, and "put" already had a flags argument with spare bits for future
expansion anyway, so forcing the extra arguments to zero would be
unnecessary.

Opinions seem to differ on whether requiring surplus arguments to be 0
is beneficial for hygiene, but the glibc prototype for prctl() is

	int prctl (int __option, ...);

so it seemed annoying to have to pass extra arguments to it just for the
sake of it.  IMHO this also makes the code at the call site less
readable, since it's not immediately apparent that all those 0s are
meaningless.

</bikeshed>

(OTOH, the extra arguments are harmless and prctl is far from being a
general-purpose syscall.)

> +			return -EINVAL;
> +		error = SET_TAGGED_ADDR_CTRL(arg2);
> +		break;
> +	case PR_GET_TAGGED_ADDR_CTRL:
> +		if (arg2 || arg3 || arg4 || arg5)
> +			return -EINVAL;
> +		error = GET_TAGGED_ADDR_CTRL();

Having a "get" prctl is probably a good idea, but is there a clear
usecase for it?

(The usecase for PR_SVE_GET_VL was always a bit dubious, since the
VL can also be read via an SVE insn or a compiler intrinsic, which is
less portable but much cheaper.  As for the PR_SVE_SET_VL_INHERIT flag
that can be read via PR_SVE_GET_VL, I've never been sure how useful it
is to be able to read that...)

[...]

Cheers
---Dave

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
                     ` (2 preceding siblings ...)
  2019-06-13 11:02   ` Dave Martin
@ 2019-06-13 11:16   ` Dave Martin
  2019-06-13 15:35     ` Catalin Marinas
  2019-06-17 13:56   ` Catalin Marinas
  2019-06-19 14:45   ` Andrey Konovalov
  5 siblings, 1 reply; 51+ messages in thread
From: Dave Martin @ 2019-06-13 11:16 UTC (permalink / raw)
  To: Andrey Konovalov
  Cc: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest, Mark Rutland,
	Szabolcs Nagy, Catalin Marinas, Will Deacon, Kostya Serebryany,
	Khalid Aziz, Felix Kuehling, Vincenzo Frascino, Jacob Bramley,
	Leon Romanovsky, Christoph Hellwig, Jason Gunthorpe,
	Evgeniy Stepanov, Kevin Brodsky, Kees Cook, Ruben Ayrapetyan,
	Ramana Radhakrishnan, Alex Williamson, Mauro Carvalho Chehab,
	Dmitry Vyukov, Greg Kroah-Hartman, Yishai Hadas, Jens Wiklander,
	Lee Smith, Alexander Deucher, Andrew Morton, enh, Robin Murphy,
	Christian Koenig, Luc Van Oostenryck

On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> From: Catalin Marinas <catalin.marinas@arm.com>
> 
> It is not desirable to relax the ABI to allow tagged user addresses into
> the kernel indiscriminately. This patch introduces a prctl() interface
> for enabling or disabling the tagged ABI with a global sysctl control
> for preventing applications from enabling the relaxed ABI (meant for
> testing user-space prctl() return error checking without reconfiguring
> the kernel). The ABI properties are inherited by threads of the same
> application and fork()'ed children but cleared on execve().
> 
> The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> MTE-specific settings like imprecise vs precise exceptions.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> ---
>  arch/arm64/include/asm/processor.h   |  6 +++
>  arch/arm64/include/asm/thread_info.h |  1 +
>  arch/arm64/include/asm/uaccess.h     |  3 +-
>  arch/arm64/kernel/process.c          | 67 ++++++++++++++++++++++++++++
>  include/uapi/linux/prctl.h           |  5 +++
>  kernel/sys.c                         | 16 +++++++
>  6 files changed, 97 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> index fcd0e691b1ea..fee457456aa8 100644
> --- a/arch/arm64/include/asm/processor.h
> +++ b/arch/arm64/include/asm/processor.h
> @@ -307,6 +307,12 @@ extern void __init minsigstksz_setup(void);
>  /* PR_PAC_RESET_KEYS prctl */
>  #define PAC_RESET_KEYS(tsk, arg)	ptrauth_prctl_reset_keys(tsk, arg)
>  
> +/* PR_TAGGED_ADDR prctl */

(A couple of comments I missed in my last reply:)

Name mismatch?

> +long set_tagged_addr_ctrl(unsigned long arg);
> +long get_tagged_addr_ctrl(void);
> +#define SET_TAGGED_ADDR_CTRL(arg)	set_tagged_addr_ctrl(arg)
> +#define GET_TAGGED_ADDR_CTRL()		get_tagged_addr_ctrl()
> +

[...]

> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> index 3767fb21a5b8..69d0be1fc708 100644
> --- a/arch/arm64/kernel/process.c
> +++ b/arch/arm64/kernel/process.c
> @@ -30,6 +30,7 @@
>  #include <linux/kernel.h>
>  #include <linux/mm.h>
>  #include <linux/stddef.h>
> +#include <linux/sysctl.h>
>  #include <linux/unistd.h>
>  #include <linux/user.h>
>  #include <linux/delay.h>
> @@ -323,6 +324,7 @@ void flush_thread(void)
>  	fpsimd_flush_thread();
>  	tls_thread_flush();
>  	flush_ptrace_hw_breakpoint(current);
> +	clear_thread_flag(TIF_TAGGED_ADDR);
>  }
>  
>  void release_thread(struct task_struct *dead_task)
> @@ -552,3 +554,68 @@ void arch_setup_new_exec(void)
>  
>  	ptrauth_thread_init_user(current);
>  }
> +
> +/*
> + * Control the relaxed ABI allowing tagged user addresses into the kernel.
> + */
> +static unsigned int tagged_addr_prctl_allowed = 1;
> +
> +long set_tagged_addr_ctrl(unsigned long arg)
> +{
> +	if (!tagged_addr_prctl_allowed)
> +		return -EINVAL;

So, tagging can actually be locked on by having a process enable it and
then some possibly unrelated process clearing tagged_addr_prctl_allowed.
That feels a bit weird.

Do we want to allow a process that has tagging on to be able to turn
it off at all?  Possibly things like CRIU might want to do that.

> +	if (is_compat_task())
> +		return -EINVAL;
> +	if (arg & ~PR_TAGGED_ADDR_ENABLE)
> +		return -EINVAL;

How do we expect this argument to be extended in the future?

I'm wondering whether this is really a bitmask or an enum, or a mixture
of the two.  Maybe it doesn't matter.

> +
> +	if (arg & PR_TAGGED_ADDR_ENABLE)
> +		set_thread_flag(TIF_TAGGED_ADDR);
> +	else
> +		clear_thread_flag(TIF_TAGGED_ADDR);

I think update_thread_flag() could be used here.

[...]

Cheers
---Dave

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-13 11:02   ` Dave Martin
@ 2019-06-13 15:26     ` Catalin Marinas
  2019-06-14  5:13       ` Kees Cook
  0 siblings, 1 reply; 51+ messages in thread
From: Catalin Marinas @ 2019-06-13 15:26 UTC (permalink / raw)
  To: Dave Martin
  Cc: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest, Mark Rutland, Szabolcs Nagy, Will Deacon,
	Kostya Serebryany, Khalid Aziz, Felix Kuehling,
	Vincenzo Frascino, Jacob Bramley, Leon Romanovsky,
	Christoph Hellwig, Jason Gunthorpe, Evgeniy Stepanov,
	Kevin Brodsky, Kees Cook, Ruben Ayrapetyan, Ramana Radhakrishnan,
	Alex Williamson, Mauro Carvalho Chehab, Dmitry Vyukov,
	Greg Kroah-Hartman, Yishai Hadas, Jens Wiklander, Lee Smith,
	Alexander Deucher, Andrew Morton, enh, Robin Murphy,
	Christian Koenig, Luc Van Oostenryck

Hi Dave,

On Thu, Jun 13, 2019 at 12:02:35PM +0100, Dave P Martin wrote:
> On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> > +/*
> > + * Global sysctl to disable the tagged user addresses support. This control
> > + * only prevents the tagged address ABI enabling via prctl() and does not
> > + * disable it for tasks that already opted in to the relaxed ABI.
> > + */
> > +static int zero;
> > +static int one = 1;
> 
> !!!
> 
> And these can't even be const without a cast.  Yuk.
> 
> (Not your fault though, but it would be nice to have a proc_dobool() to
> avoid this.)

I had the same reaction. Maybe for another patch sanitising this pattern
across the kernel.

> > --- a/include/uapi/linux/prctl.h
> > +++ b/include/uapi/linux/prctl.h
> > @@ -229,4 +229,9 @@ struct prctl_mm_map {
> >  # define PR_PAC_APDBKEY			(1UL << 3)
> >  # define PR_PAC_APGAKEY			(1UL << 4)
> >  
> > +/* Tagged user address controls for arm64 */
> > +#define PR_SET_TAGGED_ADDR_CTRL		55
> > +#define PR_GET_TAGGED_ADDR_CTRL		56
> > +# define PR_TAGGED_ADDR_ENABLE		(1UL << 0)
> > +
> 
> Do we expect this prctl to be applicable to other arches, or is it
> strictly arm64-specific?

I kept it generic, at least the tagged address part. The MTE bits later
on would be arm64-specific.

> > @@ -2492,6 +2498,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
> >  			return -EINVAL;
> >  		error = PAC_RESET_KEYS(me, arg2);
> >  		break;
> > +	case PR_SET_TAGGED_ADDR_CTRL:
> > +		if (arg3 || arg4 || arg5)
> 
> <bikeshed>
> 
> How do you anticipate these arguments being used in the future?

I don't expect them to be used at all. But since I'm not sure, I'd force
them as zero for now rather than ignored. The GET is supposed to return
the SET arg2, hence I'd rather not used the other arguments.

> For the SVE prctls I took the view that "get" could only ever mean one
> thing, and "put" already had a flags argument with spare bits for future
> expansion anyway, so forcing the extra arguments to zero would be
> unnecessary.
> 
> Opinions seem to differ on whether requiring surplus arguments to be 0
> is beneficial for hygiene, but the glibc prototype for prctl() is
> 
> 	int prctl (int __option, ...);
> 
> so it seemed annoying to have to pass extra arguments to it just for the
> sake of it.  IMHO this also makes the code at the call site less
> readable, since it's not immediately apparent that all those 0s are
> meaningless.

It's fine by me to ignore the other arguments. I just followed the
pattern of some existing prctl options. I don't have a strong opinion
either way.

> > +			return -EINVAL;
> > +		error = SET_TAGGED_ADDR_CTRL(arg2);
> > +		break;
> > +	case PR_GET_TAGGED_ADDR_CTRL:
> > +		if (arg2 || arg3 || arg4 || arg5)
> > +			return -EINVAL;
> > +		error = GET_TAGGED_ADDR_CTRL();
> 
> Having a "get" prctl is probably a good idea, but is there a clear
> usecase for it?

Not sure, maybe some other library (e.g. a JIT compiler) would like to
check whether tagged addresses have been enabled during application
start and decide to generate tagged pointers for itself. It seemed
pretty harmless, unless we add more complex things to the prctl() that
cannot be returned in one request).

-- 
Catalin

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-13 11:16   ` Dave Martin
@ 2019-06-13 15:35     ` Catalin Marinas
  2019-06-13 15:45       ` Vincenzo Frascino
  0 siblings, 1 reply; 51+ messages in thread
From: Catalin Marinas @ 2019-06-13 15:35 UTC (permalink / raw)
  To: Dave Martin
  Cc: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest, Mark Rutland, Szabolcs Nagy, Will Deacon,
	Kostya Serebryany, Khalid Aziz, Felix Kuehling,
	Vincenzo Frascino, Jacob Bramley, Leon Romanovsky,
	Christoph Hellwig, Jason Gunthorpe, Evgeniy Stepanov,
	Kevin Brodsky, Kees Cook, Ruben Ayrapetyan, Ramana Radhakrishnan,
	Alex Williamson, Mauro Carvalho Chehab, Dmitry Vyukov,
	Greg Kroah-Hartman, Yishai Hadas, Jens Wiklander, Lee Smith,
	Alexander Deucher, Andrew Morton, enh, Robin Murphy,
	Christian Koenig, Luc Van Oostenryck

On Thu, Jun 13, 2019 at 12:16:59PM +0100, Dave P Martin wrote:
> On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> > From: Catalin Marinas <catalin.marinas@arm.com>
> > 
> > It is not desirable to relax the ABI to allow tagged user addresses into
> > the kernel indiscriminately. This patch introduces a prctl() interface
> > for enabling or disabling the tagged ABI with a global sysctl control
> > for preventing applications from enabling the relaxed ABI (meant for
> > testing user-space prctl() return error checking without reconfiguring
> > the kernel). The ABI properties are inherited by threads of the same
> > application and fork()'ed children but cleared on execve().
> > 
> > The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> > MTE-specific settings like imprecise vs precise exceptions.
> > 
> > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> > ---
> >  arch/arm64/include/asm/processor.h   |  6 +++
> >  arch/arm64/include/asm/thread_info.h |  1 +
> >  arch/arm64/include/asm/uaccess.h     |  3 +-
> >  arch/arm64/kernel/process.c          | 67 ++++++++++++++++++++++++++++
> >  include/uapi/linux/prctl.h           |  5 +++
> >  kernel/sys.c                         | 16 +++++++
> >  6 files changed, 97 insertions(+), 1 deletion(-)
> > 
> > diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
> > index fcd0e691b1ea..fee457456aa8 100644
> > --- a/arch/arm64/include/asm/processor.h
> > +++ b/arch/arm64/include/asm/processor.h
> > @@ -307,6 +307,12 @@ extern void __init minsigstksz_setup(void);
> >  /* PR_PAC_RESET_KEYS prctl */
> >  #define PAC_RESET_KEYS(tsk, arg)	ptrauth_prctl_reset_keys(tsk, arg)
> >  
> > +/* PR_TAGGED_ADDR prctl */
> 
> (A couple of comments I missed in my last reply:)
> 
> Name mismatch?

Yeah, it went through several names but it seems that I didn't update
all places.

> > +long set_tagged_addr_ctrl(unsigned long arg);
> > +long get_tagged_addr_ctrl(void);
> > +#define SET_TAGGED_ADDR_CTRL(arg)	set_tagged_addr_ctrl(arg)
> > +#define GET_TAGGED_ADDR_CTRL()		get_tagged_addr_ctrl()
> > +
> 
> [...]
> 
> > diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
> > index 3767fb21a5b8..69d0be1fc708 100644
> > --- a/arch/arm64/kernel/process.c
> > +++ b/arch/arm64/kernel/process.c
> > @@ -30,6 +30,7 @@
> >  #include <linux/kernel.h>
> >  #include <linux/mm.h>
> >  #include <linux/stddef.h>
> > +#include <linux/sysctl.h>
> >  #include <linux/unistd.h>
> >  #include <linux/user.h>
> >  #include <linux/delay.h>
> > @@ -323,6 +324,7 @@ void flush_thread(void)
> >  	fpsimd_flush_thread();
> >  	tls_thread_flush();
> >  	flush_ptrace_hw_breakpoint(current);
> > +	clear_thread_flag(TIF_TAGGED_ADDR);
> >  }
> >  
> >  void release_thread(struct task_struct *dead_task)
> > @@ -552,3 +554,68 @@ void arch_setup_new_exec(void)
> >  
> >  	ptrauth_thread_init_user(current);
> >  }
> > +
> > +/*
> > + * Control the relaxed ABI allowing tagged user addresses into the kernel.
> > + */
> > +static unsigned int tagged_addr_prctl_allowed = 1;
> > +
> > +long set_tagged_addr_ctrl(unsigned long arg)
> > +{
> > +	if (!tagged_addr_prctl_allowed)
> > +		return -EINVAL;
> 
> So, tagging can actually be locked on by having a process enable it and
> then some possibly unrelated process clearing tagged_addr_prctl_allowed.
> That feels a bit weird.

The problem is that if you disable the ABI globally, lots of
applications would crash. This sysctl is meant as a way to disable the
opt-in to the TBI ABI. Another option would be a kernel command line
option (I'm not keen on a Kconfig option).

> Do we want to allow a process that has tagging on to be able to turn
> it off at all?  Possibly things like CRIU might want to do that.

I left it in for symmetry but I don't expect it to be used. A potential
use-case is doing it per subsequent threads in an application.

> > +	if (is_compat_task())
> > +		return -EINVAL;
> > +	if (arg & ~PR_TAGGED_ADDR_ENABLE)
> > +		return -EINVAL;
> 
> How do we expect this argument to be extended in the future?

Yes, for MTE. That's why I wouldn't allow random bits here.

> I'm wondering whether this is really a bitmask or an enum, or a mixture
> of the two.  Maybe it doesn't matter.

User may want to set PR_TAGGED_ADDR_ENABLE | PR_MTE_PRECISE in a single
call.

> > +	if (arg & PR_TAGGED_ADDR_ENABLE)
> > +		set_thread_flag(TIF_TAGGED_ADDR);
> > +	else
> > +		clear_thread_flag(TIF_TAGGED_ADDR);
> 
> I think update_thread_flag() could be used here.

Yes. I forgot you added this.

-- 
Catalin

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-13 15:35     ` Catalin Marinas
@ 2019-06-13 15:45       ` Vincenzo Frascino
  2019-06-13 15:57         ` Catalin Marinas
  0 siblings, 1 reply; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-13 15:45 UTC (permalink / raw)
  To: Catalin Marinas, Dave Martin
  Cc: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest, Mark Rutland, Szabolcs Nagy, Will Deacon,
	Kostya Serebryany, Khalid Aziz, Felix Kuehling, Jacob Bramley,
	Leon Romanovsky, Christoph Hellwig, Jason Gunthorpe,
	Evgeniy Stepanov, Kevin Brodsky, Kees Cook, Ruben Ayrapetyan,
	Ramana Radhakrishnan, Alex Williamson, Mauro Carvalho Chehab,
	Dmitry Vyukov, Greg Kroah-Hartman, Yishai Hadas, Jens Wiklander,
	Lee Smith, Alexander Deucher, Andrew Morton, enh, Robin Murphy,
	Christian Koenig, Luc Van Oostenryck



On 13/06/2019 16:35, Catalin Marinas wrote:
> On Thu, Jun 13, 2019 at 12:16:59PM +0100, Dave P Martin wrote:
>> On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
>>> From: Catalin Marinas <catalin.marinas@arm.com>
>>>
>>> It is not desirable to relax the ABI to allow tagged user addresses into
>>> the kernel indiscriminately. This patch introduces a prctl() interface
>>> for enabling or disabling the tagged ABI with a global sysctl control
>>> for preventing applications from enabling the relaxed ABI (meant for
>>> testing user-space prctl() return error checking without reconfiguring
>>> the kernel). The ABI properties are inherited by threads of the same
>>> application and fork()'ed children but cleared on execve().
>>>
>>> The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
>>> MTE-specific settings like imprecise vs precise exceptions.
>>>
>>> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
>>> ---
>>>  arch/arm64/include/asm/processor.h   |  6 +++
>>>  arch/arm64/include/asm/thread_info.h |  1 +
>>>  arch/arm64/include/asm/uaccess.h     |  3 +-
>>>  arch/arm64/kernel/process.c          | 67 ++++++++++++++++++++++++++++
>>>  include/uapi/linux/prctl.h           |  5 +++
>>>  kernel/sys.c                         | 16 +++++++
>>>  6 files changed, 97 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
>>> index fcd0e691b1ea..fee457456aa8 100644
>>> --- a/arch/arm64/include/asm/processor.h
>>> +++ b/arch/arm64/include/asm/processor.h
>>> @@ -307,6 +307,12 @@ extern void __init minsigstksz_setup(void);
>>>  /* PR_PAC_RESET_KEYS prctl */
>>>  #define PAC_RESET_KEYS(tsk, arg)	ptrauth_prctl_reset_keys(tsk, arg)
>>>  
>>> +/* PR_TAGGED_ADDR prctl */
>>
>> (A couple of comments I missed in my last reply:)
>>
>> Name mismatch?
> 
> Yeah, it went through several names but it seems that I didn't update
> all places.
> 
>>> +long set_tagged_addr_ctrl(unsigned long arg);
>>> +long get_tagged_addr_ctrl(void);
>>> +#define SET_TAGGED_ADDR_CTRL(arg)	set_tagged_addr_ctrl(arg)
>>> +#define GET_TAGGED_ADDR_CTRL()		get_tagged_addr_ctrl()
>>> +
>>
>> [...]
>>
>>> diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
>>> index 3767fb21a5b8..69d0be1fc708 100644
>>> --- a/arch/arm64/kernel/process.c
>>> +++ b/arch/arm64/kernel/process.c
>>> @@ -30,6 +30,7 @@
>>>  #include <linux/kernel.h>
>>>  #include <linux/mm.h>
>>>  #include <linux/stddef.h>
>>> +#include <linux/sysctl.h>
>>>  #include <linux/unistd.h>
>>>  #include <linux/user.h>
>>>  #include <linux/delay.h>
>>> @@ -323,6 +324,7 @@ void flush_thread(void)
>>>  	fpsimd_flush_thread();
>>>  	tls_thread_flush();
>>>  	flush_ptrace_hw_breakpoint(current);
>>> +	clear_thread_flag(TIF_TAGGED_ADDR);
>>>  }
>>>  
>>>  void release_thread(struct task_struct *dead_task)
>>> @@ -552,3 +554,68 @@ void arch_setup_new_exec(void)
>>>  
>>>  	ptrauth_thread_init_user(current);
>>>  }
>>> +
>>> +/*
>>> + * Control the relaxed ABI allowing tagged user addresses into the kernel.
>>> + */
>>> +static unsigned int tagged_addr_prctl_allowed = 1;
>>> +
>>> +long set_tagged_addr_ctrl(unsigned long arg)
>>> +{
>>> +	if (!tagged_addr_prctl_allowed)
>>> +		return -EINVAL;
>>
>> So, tagging can actually be locked on by having a process enable it and
>> then some possibly unrelated process clearing tagged_addr_prctl_allowed.
>> That feels a bit weird.
> 
> The problem is that if you disable the ABI globally, lots of
> applications would crash. This sysctl is meant as a way to disable the
> opt-in to the TBI ABI. Another option would be a kernel command line
> option (I'm not keen on a Kconfig option).
>

Why you are not keen on a Kconfig option?

>> Do we want to allow a process that has tagging on to be able to turn
>> it off at all?  Possibly things like CRIU might want to do that.
> 
> I left it in for symmetry but I don't expect it to be used. A potential
> use-case is doing it per subsequent threads in an application.
> 
>>> +	if (is_compat_task())
>>> +		return -EINVAL;
>>> +	if (arg & ~PR_TAGGED_ADDR_ENABLE)
>>> +		return -EINVAL;
>>
>> How do we expect this argument to be extended in the future?
> 
> Yes, for MTE. That's why I wouldn't allow random bits here.
> 
>> I'm wondering whether this is really a bitmask or an enum, or a mixture
>> of the two.  Maybe it doesn't matter.
> 
> User may want to set PR_TAGGED_ADDR_ENABLE | PR_MTE_PRECISE in a single
> call.
> 
>>> +	if (arg & PR_TAGGED_ADDR_ENABLE)
>>> +		set_thread_flag(TIF_TAGGED_ADDR);
>>> +	else
>>> +		clear_thread_flag(TIF_TAGGED_ADDR);
>>
>> I think update_thread_flag() could be used here.
> 
> Yes. I forgot you added this.
> 

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-13 15:45       ` Vincenzo Frascino
@ 2019-06-13 15:57         ` Catalin Marinas
  2019-06-13 16:15           ` Vincenzo Frascino
  0 siblings, 1 reply; 51+ messages in thread
From: Catalin Marinas @ 2019-06-13 15:57 UTC (permalink / raw)
  To: Vincenzo Frascino
  Cc: Dave Martin, Andrey Konovalov, linux-arm-kernel, linux-mm,
	linux-kernel, amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest, Mark Rutland, Szabolcs Nagy, Will Deacon,
	Kostya Serebryany, Khalid Aziz, Felix Kuehling, Jacob Bramley,
	Leon Romanovsky, Christoph Hellwig, Jason Gunthorpe,
	Evgeniy Stepanov, Kevin Brodsky, Kees Cook, Ruben Ayrapetyan,
	Ramana Radhakrishnan, Alex Williamson, Mauro Carvalho Chehab,
	Dmitry Vyukov, Greg Kroah-Hartman, Yishai Hadas, Jens Wiklander,
	Lee Smith, Alexander Deucher, Andrew Morton, enh, Robin Murphy,
	Christian Koenig, Luc Van Oostenryck

On Thu, Jun 13, 2019 at 04:45:54PM +0100, Vincenzo Frascino wrote:
> On 13/06/2019 16:35, Catalin Marinas wrote:
> > On Thu, Jun 13, 2019 at 12:16:59PM +0100, Dave P Martin wrote:
> >> On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> >>> +
> >>> +/*
> >>> + * Control the relaxed ABI allowing tagged user addresses into the kernel.
> >>> + */
> >>> +static unsigned int tagged_addr_prctl_allowed = 1;
> >>> +
> >>> +long set_tagged_addr_ctrl(unsigned long arg)
> >>> +{
> >>> +	if (!tagged_addr_prctl_allowed)
> >>> +		return -EINVAL;
> >>
> >> So, tagging can actually be locked on by having a process enable it and
> >> then some possibly unrelated process clearing tagged_addr_prctl_allowed.
> >> That feels a bit weird.
> > 
> > The problem is that if you disable the ABI globally, lots of
> > applications would crash. This sysctl is meant as a way to disable the
> > opt-in to the TBI ABI. Another option would be a kernel command line
> > option (I'm not keen on a Kconfig option).
> 
> Why you are not keen on a Kconfig option?

Because I don't want to rebuild the kernel/reboot just to be able to
test how user space handles the ABI opt-in. I'm ok with a Kconfig option
to disable this globally in addition to a run-time option (if actually
needed, I'm not sure).

-- 
Catalin

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-13 15:57         ` Catalin Marinas
@ 2019-06-13 16:15           ` Vincenzo Frascino
  0 siblings, 0 replies; 51+ messages in thread
From: Vincenzo Frascino @ 2019-06-13 16:15 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: Dave Martin, Andrey Konovalov, linux-arm-kernel, linux-mm,
	linux-kernel, amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest, Mark Rutland, Szabolcs Nagy, Will Deacon,
	Kostya Serebryany, Khalid Aziz, Felix Kuehling, Jacob Bramley,
	Leon Romanovsky, Christoph Hellwig, Jason Gunthorpe,
	Evgeniy Stepanov, Kevin Brodsky, Kees Cook, Ruben Ayrapetyan,
	Ramana Radhakrishnan, Alex Williamson, Mauro Carvalho Chehab,
	Dmitry Vyukov, Greg Kroah-Hartman, Yishai Hadas, Jens Wiklander,
	Lee Smith, Alexander Deucher, Andrew Morton, enh, Robin Murphy,
	Christian Koenig, Luc Van Oostenryck


On 13/06/2019 16:57, Catalin Marinas wrote:
> On Thu, Jun 13, 2019 at 04:45:54PM +0100, Vincenzo Frascino wrote:
>> On 13/06/2019 16:35, Catalin Marinas wrote:
>>> On Thu, Jun 13, 2019 at 12:16:59PM +0100, Dave P Martin wrote:
>>>> On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
>>>>> +
>>>>> +/*
>>>>> + * Control the relaxed ABI allowing tagged user addresses into the kernel.
>>>>> + */
>>>>> +static unsigned int tagged_addr_prctl_allowed = 1;
>>>>> +
>>>>> +long set_tagged_addr_ctrl(unsigned long arg)
>>>>> +{
>>>>> +	if (!tagged_addr_prctl_allowed)
>>>>> +		return -EINVAL;
>>>>
>>>> So, tagging can actually be locked on by having a process enable it and
>>>> then some possibly unrelated process clearing tagged_addr_prctl_allowed.
>>>> That feels a bit weird.
>>>
>>> The problem is that if you disable the ABI globally, lots of
>>> applications would crash. This sysctl is meant as a way to disable the
>>> opt-in to the TBI ABI. Another option would be a kernel command line
>>> option (I'm not keen on a Kconfig option).
>>
>> Why you are not keen on a Kconfig option?
> 
> Because I don't want to rebuild the kernel/reboot just to be able to
> test how user space handles the ABI opt-in. I'm ok with a Kconfig option
> to disable this globally in addition to a run-time option (if actually
> needed, I'm not sure).
> 
There might be scenarios (i.e. embedded) in which this is not needed, hence
having a config option (maybe Y by default) that removes from the kernel the
whole feature would be good, obviously in conjunction with the run-time option.

Based on my previous review, if we move out the code from process.c in its own
independent file when the Kconfig option is turned off we could remove the
entire object from the kernel (this would remove the sysctl and let still the
prctl return -EINVAL).

These changes though could be done successively with a separate patch set, if
the Kconfig is meant to be Y by default.

-- 
Regards,
Vincenzo

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-13 15:26     ` Catalin Marinas
@ 2019-06-14  5:13       ` Kees Cook
  2019-06-18  9:18         ` Dave Martin
  0 siblings, 1 reply; 51+ messages in thread
From: Kees Cook @ 2019-06-14  5:13 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: Dave Martin, Andrey Konovalov, linux-arm-kernel, linux-mm,
	linux-kernel, amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest, Mark Rutland, Szabolcs Nagy, Will Deacon,
	Kostya Serebryany, Khalid Aziz, Felix Kuehling,
	Vincenzo Frascino, Jacob Bramley, Leon Romanovsky,
	Christoph Hellwig, Jason Gunthorpe, Evgeniy Stepanov,
	Kevin Brodsky, Ruben Ayrapetyan, Ramana Radhakrishnan,
	Alex Williamson, Mauro Carvalho Chehab, Dmitry Vyukov,
	Greg Kroah-Hartman, Yishai Hadas, Jens Wiklander, Lee Smith,
	Alexander Deucher, Andrew Morton, enh, Robin Murphy,
	Christian Koenig, Luc Van Oostenryck

On Thu, Jun 13, 2019 at 04:26:32PM +0100, Catalin Marinas wrote:
> On Thu, Jun 13, 2019 at 12:02:35PM +0100, Dave P Martin wrote:
> > On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> > > +static int zero;
> > > +static int one = 1;
> > 
> > !!!
> > 
> > And these can't even be const without a cast.  Yuk.
> > 
> > (Not your fault though, but it would be nice to have a proc_dobool() to
> > avoid this.)
> 
> I had the same reaction. Maybe for another patch sanitising this pattern
> across the kernel.

That's actually already happening (via -mm tree last I looked). tl;dr:
it ends up using a cast hidden in a macro. It's in linux-next already
along with a checkpatch.pl addition to yell about doing what's being
done here. ;)

https://lore.kernel.org/lkml/20190430180111.10688-1-mcroce@redhat.com/#r

-- 
Kees Cook

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
                     ` (3 preceding siblings ...)
  2019-06-13 11:16   ` Dave Martin
@ 2019-06-17 13:56   ` Catalin Marinas
  2019-06-17 16:56     ` Szabolcs Nagy
  2019-06-17 16:57     ` Evgenii Stepanov
  2019-06-19 14:45   ` Andrey Konovalov
  5 siblings, 2 replies; 51+ messages in thread
From: Catalin Marinas @ 2019-06-17 13:56 UTC (permalink / raw)
  To: Andrey Konovalov
  Cc: linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest, Vincenzo Frascino,
	Will Deacon, Mark Rutland, Andrew Morton, Greg Kroah-Hartman,
	Kees Cook, Yishai Hadas, Felix Kuehling, Alexander Deucher,
	Christian Koenig, Mauro Carvalho Chehab, Jens Wiklander,
	Alex Williamson, Leon Romanovsky, Luc Van Oostenryck,
	Dave Martin, Khalid Aziz, enh, Jason Gunthorpe,
	Christoph Hellwig, Dmitry Vyukov, Kostya Serebryany,
	Evgeniy Stepanov, Lee Smith, Ramana Radhakrishnan, Jacob Bramley,
	Ruben Ayrapetyan, Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> From: Catalin Marinas <catalin.marinas@arm.com>
> 
> It is not desirable to relax the ABI to allow tagged user addresses into
> the kernel indiscriminately. This patch introduces a prctl() interface
> for enabling or disabling the tagged ABI with a global sysctl control
> for preventing applications from enabling the relaxed ABI (meant for
> testing user-space prctl() return error checking without reconfiguring
> the kernel). The ABI properties are inherited by threads of the same
> application and fork()'ed children but cleared on execve().
> 
> The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> MTE-specific settings like imprecise vs precise exceptions.
> 
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

A question for the user-space folk: if an application opts in to this
ABI, would you want the sigcontext.fault_address and/or siginfo.si_addr
to contain the tag? We currently clear it early in the arm64 entry.S but
we could find a way to pass it down if needed.

-- 
Catalin

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-17 13:56   ` Catalin Marinas
@ 2019-06-17 16:56     ` Szabolcs Nagy
  2019-06-17 16:57     ` Evgenii Stepanov
  1 sibling, 0 replies; 51+ messages in thread
From: Szabolcs Nagy @ 2019-06-17 16:56 UTC (permalink / raw)
  To: Catalin Marinas, Andrey Konovalov
  Cc: nd, linux-arm-kernel, linux-mm, linux-kernel, amd-gfx, dri-devel,
	linux-rdma, linux-media, kvm, linux-kselftest, Vincenzo Frascino,
	Will Deacon, Mark Rutland, Andrew Morton, Greg Kroah-Hartman,
	Kees Cook, Yishai Hadas, Felix Kuehling, Alexander Deucher,
	Christian Koenig, Mauro Carvalho Chehab, Jens Wiklander,
	Alex Williamson, Leon Romanovsky, Luc Van Oostenryck,
	Dave P Martin, Khalid Aziz, enh, Jason Gunthorpe,
	Christoph Hellwig, Dmitry Vyukov, Kostya Serebryany,
	Evgeniy Stepanov, Lee Smith, Ramana Radhakrishnan, Jacob Bramley,
	Ruben Ayrapetyan, Robin Murphy, Kevin Brodsky

On 17/06/2019 14:56, Catalin Marinas wrote:
> On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
>> From: Catalin Marinas <catalin.marinas@arm.com>
>>
>> It is not desirable to relax the ABI to allow tagged user addresses into
>> the kernel indiscriminately. This patch introduces a prctl() interface
>> for enabling or disabling the tagged ABI with a global sysctl control
>> for preventing applications from enabling the relaxed ABI (meant for
>> testing user-space prctl() return error checking without reconfiguring
>> the kernel). The ABI properties are inherited by threads of the same
>> application and fork()'ed children but cleared on execve().
>>
>> The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
>> MTE-specific settings like imprecise vs precise exceptions.
>>
>> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> 
> A question for the user-space folk: if an application opts in to this
> ABI, would you want the sigcontext.fault_address and/or siginfo.si_addr
> to contain the tag? We currently clear it early in the arm64 entry.S but
> we could find a way to pass it down if needed.

to me it makes sense to keep the tag in si_addr / fault_address.

but i don't know in detail how those fields are used currently.

keeping the tag is certainly useful for MTE to debug wrong tag
failures unless there is a separate mechanism for that.


^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-17 13:56   ` Catalin Marinas
  2019-06-17 16:56     ` Szabolcs Nagy
@ 2019-06-17 16:57     ` Evgenii Stepanov
  2019-06-17 17:18       ` Catalin Marinas
  1 sibling, 1 reply; 51+ messages in thread
From: Evgenii Stepanov @ 2019-06-17 16:57 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: Andrey Konovalov, Linux ARM, Linux Memory Management List, LKML,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	open list:KERNEL SELFTEST FRAMEWORK, Vincenzo Frascino,
	Will Deacon, Mark Rutland, Andrew Morton, Greg Kroah-Hartman,
	Kees Cook, Yishai Hadas, Felix Kuehling, Alexander Deucher,
	Christian Koenig, Mauro Carvalho Chehab, Jens Wiklander,
	Alex Williamson, Leon Romanovsky, Luc Van Oostenryck,
	Dave Martin, Khalid Aziz, enh, Jason Gunthorpe,
	Christoph Hellwig, Dmitry Vyukov, Kostya Serebryany, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On Mon, Jun 17, 2019 at 6:56 AM Catalin Marinas <catalin.marinas@arm.com> wrote:
>
> On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> > From: Catalin Marinas <catalin.marinas@arm.com>
> >
> > It is not desirable to relax the ABI to allow tagged user addresses into
> > the kernel indiscriminately. This patch introduces a prctl() interface
> > for enabling or disabling the tagged ABI with a global sysctl control
> > for preventing applications from enabling the relaxed ABI (meant for
> > testing user-space prctl() return error checking without reconfiguring
> > the kernel). The ABI properties are inherited by threads of the same
> > application and fork()'ed children but cleared on execve().
> >
> > The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> > MTE-specific settings like imprecise vs precise exceptions.
> >
> > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
>
> A question for the user-space folk: if an application opts in to this
> ABI, would you want the sigcontext.fault_address and/or siginfo.si_addr
> to contain the tag? We currently clear it early in the arm64 entry.S but
> we could find a way to pass it down if needed.

For HWASan this would not be useful because we instrument memory
accesses with explicit checks anyway. For MTE, on the other hand, it
would be very convenient to know the fault address tag without
disassembling the code.

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-17 16:57     ` Evgenii Stepanov
@ 2019-06-17 17:18       ` Catalin Marinas
  2019-06-17 21:59         ` Evgenii Stepanov
  0 siblings, 1 reply; 51+ messages in thread
From: Catalin Marinas @ 2019-06-17 17:18 UTC (permalink / raw)
  To: Evgenii Stepanov
  Cc: Andrey Konovalov, Linux ARM, Linux Memory Management List, LKML,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	open list:KERNEL SELFTEST FRAMEWORK, Vincenzo Frascino,
	Will Deacon, Mark Rutland, Andrew Morton, Greg Kroah-Hartman,
	Kees Cook, Yishai Hadas, Felix Kuehling, Alexander Deucher,
	Christian Koenig, Mauro Carvalho Chehab, Jens Wiklander,
	Alex Williamson, Leon Romanovsky, Luc Van Oostenryck,
	Dave Martin, Khalid Aziz, enh, Jason Gunthorpe,
	Christoph Hellwig, Dmitry Vyukov, Kostya Serebryany, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On Mon, Jun 17, 2019 at 09:57:36AM -0700, Evgenii Stepanov wrote:
> On Mon, Jun 17, 2019 at 6:56 AM Catalin Marinas <catalin.marinas@arm.com> wrote:
> > On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> > > From: Catalin Marinas <catalin.marinas@arm.com>
> > >
> > > It is not desirable to relax the ABI to allow tagged user addresses into
> > > the kernel indiscriminately. This patch introduces a prctl() interface
> > > for enabling or disabling the tagged ABI with a global sysctl control
> > > for preventing applications from enabling the relaxed ABI (meant for
> > > testing user-space prctl() return error checking without reconfiguring
> > > the kernel). The ABI properties are inherited by threads of the same
> > > application and fork()'ed children but cleared on execve().
> > >
> > > The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> > > MTE-specific settings like imprecise vs precise exceptions.
> > >
> > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> >
> > A question for the user-space folk: if an application opts in to this
> > ABI, would you want the sigcontext.fault_address and/or siginfo.si_addr
> > to contain the tag? We currently clear it early in the arm64 entry.S but
> > we could find a way to pass it down if needed.
> 
> For HWASan this would not be useful because we instrument memory
> accesses with explicit checks anyway. For MTE, on the other hand, it
> would be very convenient to know the fault address tag without
> disassembling the code.

I could as this differently: does anything break if, once the user
opts in to TBI, fault_address and/or si_addr have non-zero top byte?

Alternatively, we could present the original FAR_EL1 register as a
separate field as we do with ESR_EL1, independently of whether the user
opted in to TBI or not.

-- 
Catalin

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-17 17:18       ` Catalin Marinas
@ 2019-06-17 21:59         ` Evgenii Stepanov
  0 siblings, 0 replies; 51+ messages in thread
From: Evgenii Stepanov @ 2019-06-17 21:59 UTC (permalink / raw)
  To: Catalin Marinas
  Cc: Andrey Konovalov, Linux ARM, Linux Memory Management List, LKML,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	open list:KERNEL SELFTEST FRAMEWORK, Vincenzo Frascino,
	Will Deacon, Mark Rutland, Andrew Morton, Greg Kroah-Hartman,
	Kees Cook, Yishai Hadas, Felix Kuehling, Alexander Deucher,
	Christian Koenig, Mauro Carvalho Chehab, Jens Wiklander,
	Alex Williamson, Leon Romanovsky, Luc Van Oostenryck,
	Dave Martin, Khalid Aziz, enh, Jason Gunthorpe,
	Christoph Hellwig, Dmitry Vyukov, Kostya Serebryany, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On Mon, Jun 17, 2019 at 10:18 AM Catalin Marinas
<catalin.marinas@arm.com> wrote:
>
> On Mon, Jun 17, 2019 at 09:57:36AM -0700, Evgenii Stepanov wrote:
> > On Mon, Jun 17, 2019 at 6:56 AM Catalin Marinas <catalin.marinas@arm.com> wrote:
> > > On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> > > > From: Catalin Marinas <catalin.marinas@arm.com>
> > > >
> > > > It is not desirable to relax the ABI to allow tagged user addresses into
> > > > the kernel indiscriminately. This patch introduces a prctl() interface
> > > > for enabling or disabling the tagged ABI with a global sysctl control
> > > > for preventing applications from enabling the relaxed ABI (meant for
> > > > testing user-space prctl() return error checking without reconfiguring
> > > > the kernel). The ABI properties are inherited by threads of the same
> > > > application and fork()'ed children but cleared on execve().
> > > >
> > > > The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> > > > MTE-specific settings like imprecise vs precise exceptions.
> > > >
> > > > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> > >
> > > A question for the user-space folk: if an application opts in to this
> > > ABI, would you want the sigcontext.fault_address and/or siginfo.si_addr
> > > to contain the tag? We currently clear it early in the arm64 entry.S but
> > > we could find a way to pass it down if needed.
> >
> > For HWASan this would not be useful because we instrument memory
> > accesses with explicit checks anyway. For MTE, on the other hand, it
> > would be very convenient to know the fault address tag without
> > disassembling the code.
>
> I could as this differently: does anything break if, once the user
> opts in to TBI, fault_address and/or si_addr have non-zero top byte?

I think it would be fine.

> Alternatively, we could present the original FAR_EL1 register as a
> separate field as we do with ESR_EL1, independently of whether the user
> opted in to TBI or not.
>
> --
> Catalin

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-14  5:13       ` Kees Cook
@ 2019-06-18  9:18         ` Dave Martin
  0 siblings, 0 replies; 51+ messages in thread
From: Dave Martin @ 2019-06-18  9:18 UTC (permalink / raw)
  To: Kees Cook
  Cc: Catalin Marinas, Mark Rutland, kvm, Christian Koenig,
	Szabolcs Nagy, Will Deacon, dri-devel, Kostya Serebryany,
	Khalid Aziz, Lee Smith, linux-kselftest, Vincenzo Frascino,
	Jacob Bramley, Leon Romanovsky, linux-rdma, amd-gfx,
	Christoph Hellwig, Jason Gunthorpe, Dmitry Vyukov,
	Evgeniy Stepanov, linux-media, Ruben Ayrapetyan,
	Andrey Konovalov, Kevin Brodsky, Alex Williamson,
	Mauro Carvalho Chehab, linux-arm-kernel, linux-mm,
	Greg Kroah-Hartman, Felix Kuehling, linux-kernel, Jens Wiklander,
	Ramana Radhakrishnan, Alexander Deucher, Andrew Morton, enh,
	Robin Murphy, Yishai Hadas, Luc Van Oostenryck

On Thu, Jun 13, 2019 at 10:13:54PM -0700, Kees Cook wrote:
> On Thu, Jun 13, 2019 at 04:26:32PM +0100, Catalin Marinas wrote:
> > On Thu, Jun 13, 2019 at 12:02:35PM +0100, Dave P Martin wrote:
> > > On Wed, Jun 12, 2019 at 01:43:20PM +0200, Andrey Konovalov wrote:
> > > > +static int zero;
> > > > +static int one = 1;
> > > 
> > > !!!
> > > 
> > > And these can't even be const without a cast.  Yuk.
> > > 
> > > (Not your fault though, but it would be nice to have a proc_dobool() to
> > > avoid this.)
> > 
> > I had the same reaction. Maybe for another patch sanitising this pattern
> > across the kernel.
> 
> That's actually already happening (via -mm tree last I looked). tl;dr:
> it ends up using a cast hidden in a macro. It's in linux-next already
> along with a checkpatch.pl addition to yell about doing what's being
> done here. ;)
> 
> https://lore.kernel.org/lkml/20190430180111.10688-1-mcroce@redhat.com/#r

Hmmm, that is marginally less bad.

Ideally we'd have a union in there, not just a bunch of void *.  I may
look at that someday...

Cheers
---Dave

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
                     ` (4 preceding siblings ...)
  2019-06-17 13:56   ` Catalin Marinas
@ 2019-06-19 14:45   ` Andrey Konovalov
  2019-06-19 15:29     ` Catalin Marinas
  5 siblings, 1 reply; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-19 14:45 UTC (permalink / raw)
  To: Linux ARM, Linux Memory Management List, LKML, amd-gfx,
	dri-devel, linux-rdma, linux-media, kvm,
	open list:KERNEL SELFTEST FRAMEWORK
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, Khalid Aziz,
	enh, Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On Wed, Jun 12, 2019 at 1:43 PM Andrey Konovalov <andreyknvl@google.com> wrote:
>
> From: Catalin Marinas <catalin.marinas@arm.com>
>
> It is not desirable to relax the ABI to allow tagged user addresses into
> the kernel indiscriminately. This patch introduces a prctl() interface
> for enabling or disabling the tagged ABI with a global sysctl control
> for preventing applications from enabling the relaxed ABI (meant for
> testing user-space prctl() return error checking without reconfiguring
> the kernel). The ABI properties are inherited by threads of the same
> application and fork()'ed children but cleared on execve().
>
> The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> MTE-specific settings like imprecise vs precise exceptions.
>
> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>

Catalin, would you like to do the requested changes to this patch
yourself and send it to me or should I do that?

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI
  2019-06-19 14:45   ` Andrey Konovalov
@ 2019-06-19 15:29     ` Catalin Marinas
  0 siblings, 0 replies; 51+ messages in thread
From: Catalin Marinas @ 2019-06-19 15:29 UTC (permalink / raw)
  To: Andrey Konovalov
  Cc: Linux ARM, Linux Memory Management List, LKML, amd-gfx,
	dri-devel, linux-rdma, linux-media, kvm,
	open list:KERNEL SELFTEST FRAMEWORK, Vincenzo Frascino,
	Will Deacon, Mark Rutland, Andrew Morton, Greg Kroah-Hartman,
	Kees Cook, Yishai Hadas, Felix Kuehling, Alexander Deucher,
	Christian Koenig, Mauro Carvalho Chehab, Jens Wiklander,
	Alex Williamson, Leon Romanovsky, Luc Van Oostenryck,
	Dave Martin, Khalid Aziz, enh, Jason Gunthorpe,
	Christoph Hellwig, Dmitry Vyukov, Kostya Serebryany,
	Evgeniy Stepanov, Lee Smith, Ramana Radhakrishnan, Jacob Bramley,
	Ruben Ayrapetyan, Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On Wed, Jun 19, 2019 at 04:45:02PM +0200, Andrey Konovalov wrote:
> On Wed, Jun 12, 2019 at 1:43 PM Andrey Konovalov <andreyknvl@google.com> wrote:
> > From: Catalin Marinas <catalin.marinas@arm.com>
> >
> > It is not desirable to relax the ABI to allow tagged user addresses into
> > the kernel indiscriminately. This patch introduces a prctl() interface
> > for enabling or disabling the tagged ABI with a global sysctl control
> > for preventing applications from enabling the relaxed ABI (meant for
> > testing user-space prctl() return error checking without reconfiguring
> > the kernel). The ABI properties are inherited by threads of the same
> > application and fork()'ed children but cleared on execve().
> >
> > The PR_SET_TAGGED_ADDR_CTRL will be expanded in the future to handle
> > MTE-specific settings like imprecise vs precise exceptions.
> >
> > Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
> 
> Catalin, would you like to do the requested changes to this patch
> yourself and send it to me or should I do that?

I'll send you an updated version this week.

-- 
Catalin

^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls
  2019-06-12 11:43 ` [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov
  2019-06-12 14:31   ` Vincenzo Frascino
@ 2019-06-19 15:55   ` Khalid Aziz
  2019-06-19 16:46     ` Khalid Aziz
  1 sibling, 1 reply; 51+ messages in thread
From: Khalid Aziz @ 2019-06-19 15:55 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 6/12/19 5:43 AM, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> This patch allows tagged pointers to be passed to the following memory
> syscalls: get_mempolicy, madvise, mbind, mincore, mlock, mlock2, mprotect,
> mremap, msync, munlock, move_pages.
> 
> The mmap and mremap syscalls do not currently accept tagged addresses.
> Architectures may interpret the tag as a background colour for the
> corresponding vma.
> 
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---

Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>


>  mm/madvise.c   | 2 ++
>  mm/mempolicy.c | 3 +++
>  mm/migrate.c   | 2 +-
>  mm/mincore.c   | 2 ++
>  mm/mlock.c     | 4 ++++
>  mm/mprotect.c  | 2 ++
>  mm/mremap.c    | 7 +++++++
>  mm/msync.c     | 2 ++
>  8 files changed, 23 insertions(+), 1 deletion(-)
> 
> diff --git a/mm/madvise.c b/mm/madvise.c
> index 628022e674a7..39b82f8a698f 100644
> --- a/mm/madvise.c
> +++ b/mm/madvise.c
> @@ -810,6 +810,8 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
>  	size_t len;
>  	struct blk_plug plug;
>  
> +	start = untagged_addr(start);
> +
>  	if (!madvise_behavior_valid(behavior))
>  		return error;
>  
> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> index 01600d80ae01..78e0a88b2680 100644
> --- a/mm/mempolicy.c
> +++ b/mm/mempolicy.c
> @@ -1360,6 +1360,7 @@ static long kernel_mbind(unsigned long start, unsigned long len,
>  	int err;
>  	unsigned short mode_flags;
>  
> +	start = untagged_addr(start);
>  	mode_flags = mode & MPOL_MODE_FLAGS;
>  	mode &= ~MPOL_MODE_FLAGS;
>  	if (mode >= MPOL_MAX)
> @@ -1517,6 +1518,8 @@ static int kernel_get_mempolicy(int __user *policy,
>  	int uninitialized_var(pval);
>  	nodemask_t nodes;
>  
> +	addr = untagged_addr(addr);
> +
>  	if (nmask != NULL && maxnode < nr_node_ids)
>  		return -EINVAL;
>  
> diff --git a/mm/migrate.c b/mm/migrate.c
> index f2ecc2855a12..d22c45cf36b2 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -1616,7 +1616,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>  			goto out_flush;
>  		if (get_user(node, nodes + i))
>  			goto out_flush;
> -		addr = (unsigned long)p;
> +		addr = (unsigned long)untagged_addr(p);
>  
>  		err = -ENODEV;
>  		if (node < 0 || node >= MAX_NUMNODES)
> diff --git a/mm/mincore.c b/mm/mincore.c
> index c3f058bd0faf..64c322ed845c 100644
> --- a/mm/mincore.c
> +++ b/mm/mincore.c
> @@ -249,6 +249,8 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
>  	unsigned long pages;
>  	unsigned char *tmp;
>  
> +	start = untagged_addr(start);
> +
>  	/* Check the start address: needs to be page-aligned.. */
>  	if (start & ~PAGE_MASK)
>  		return -EINVAL;
> diff --git a/mm/mlock.c b/mm/mlock.c
> index 080f3b36415b..e82609eaa428 100644
> --- a/mm/mlock.c
> +++ b/mm/mlock.c
> @@ -674,6 +674,8 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla
>  	unsigned long lock_limit;
>  	int error = -ENOMEM;
>  
> +	start = untagged_addr(start);
> +
>  	if (!can_do_mlock())
>  		return -EPERM;
>  
> @@ -735,6 +737,8 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
>  {
>  	int ret;
>  
> +	start = untagged_addr(start);
> +
>  	len = PAGE_ALIGN(len + (offset_in_page(start)));
>  	start &= PAGE_MASK;
>  
> diff --git a/mm/mprotect.c b/mm/mprotect.c
> index bf38dfbbb4b4..19f981b733bc 100644
> --- a/mm/mprotect.c
> +++ b/mm/mprotect.c
> @@ -465,6 +465,8 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
>  	const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
>  				(prot & PROT_READ);
>  
> +	start = untagged_addr(start);
> +
>  	prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
>  	if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
>  		return -EINVAL;
> diff --git a/mm/mremap.c b/mm/mremap.c
> index fc241d23cd97..64c9a3b8be0a 100644
> --- a/mm/mremap.c
> +++ b/mm/mremap.c
> @@ -606,6 +606,13 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
>  	LIST_HEAD(uf_unmap_early);
>  	LIST_HEAD(uf_unmap);
>  
> +	/*
> +	 * Architectures may interpret the tag passed to mmap as a background
> +	 * colour for the corresponding vma. For mremap we don't allow tagged
> +	 * new_addr to preserve similar behaviour to mmap.
> +	 */
> +	addr = untagged_addr(addr);
> +
>  	if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
>  		return ret;
>  
> diff --git a/mm/msync.c b/mm/msync.c
> index ef30a429623a..c3bd3e75f687 100644
> --- a/mm/msync.c
> +++ b/mm/msync.c
> @@ -37,6 +37,8 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
>  	int unmapped_error = 0;
>  	int error = -EINVAL;
>  
> +	start = untagged_addr(start);
> +
>  	if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
>  		goto out;
>  	if (offset_in_page(start))
> 



^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c
  2019-06-12 11:43 ` [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
  2019-06-12 14:33   ` Vincenzo Frascino
@ 2019-06-19 16:41   ` Khalid Aziz
  1 sibling, 0 replies; 51+ messages in thread
From: Khalid Aziz @ 2019-06-19 16:41 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 6/12/19 5:43 AM, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> mm/gup.c provides a kernel interface that accepts user addresses and
> manipulates user pages directly (for example get_user_pages, that is used
> by the futex syscall). Since a user can provided tagged addresses, we need
> to handle this case.
> 
> Add untagging to gup.c functions that use user addresses for vma lookups.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---

Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>


>  mm/gup.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/mm/gup.c b/mm/gup.c
> index ddde097cf9e4..c37df3d455a2 100644
> --- a/mm/gup.c
> +++ b/mm/gup.c
> @@ -802,6 +802,8 @@ static long __get_user_pages(struct task_struct *tsk, struct mm_struct *mm,
>  	if (!nr_pages)
>  		return 0;
>  
> +	start = untagged_addr(start);
> +
>  	VM_BUG_ON(!!pages != !!(gup_flags & FOLL_GET));
>  
>  	/*
> @@ -964,6 +966,8 @@ int fixup_user_fault(struct task_struct *tsk, struct mm_struct *mm,
>  	struct vm_area_struct *vma;
>  	vm_fault_t ret, major = 0;
>  
> +	address = untagged_addr(address);
> +
>  	if (unlocked)
>  		fault_flags |= FAULT_FLAG_ALLOW_RETRY;
>  
> 



^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls
  2019-06-19 15:55   ` Khalid Aziz
@ 2019-06-19 16:46     ` Khalid Aziz
  2019-06-24 14:22       ` Andrey Konovalov
  0 siblings, 1 reply; 51+ messages in thread
From: Khalid Aziz @ 2019-06-19 16:46 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 6/19/19 9:55 AM, Khalid Aziz wrote:
> On 6/12/19 5:43 AM, Andrey Konovalov wrote:
>> This patch is a part of a series that extends arm64 kernel ABI to allow to
>> pass tagged user pointers (with the top byte set to something else other
>> than 0x00) as syscall arguments.
>>
>> This patch allows tagged pointers to be passed to the following memory
>> syscalls: get_mempolicy, madvise, mbind, mincore, mlock, mlock2, mprotect,
>> mremap, msync, munlock, move_pages.
>>
>> The mmap and mremap syscalls do not currently accept tagged addresses.
>> Architectures may interpret the tag as a background colour for the
>> corresponding vma.
>>
>> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
>> Reviewed-by: Kees Cook <keescook@chromium.org>
>> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
>> ---
> 
> Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
> 
> 

I would also recommend updating commit log for all the patches in this
series that are changing files under mm/ as opposed to arch/arm64 to not
reference arm64 kernel ABI since the change applies to every
architecture. So something along the lines of "This patch is part of a
series that extends kernel ABI to allow......."

--
Khalid


>>  mm/madvise.c   | 2 ++
>>  mm/mempolicy.c | 3 +++
>>  mm/migrate.c   | 2 +-
>>  mm/mincore.c   | 2 ++
>>  mm/mlock.c     | 4 ++++
>>  mm/mprotect.c  | 2 ++
>>  mm/mremap.c    | 7 +++++++
>>  mm/msync.c     | 2 ++
>>  8 files changed, 23 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/madvise.c b/mm/madvise.c
>> index 628022e674a7..39b82f8a698f 100644
>> --- a/mm/madvise.c
>> +++ b/mm/madvise.c
>> @@ -810,6 +810,8 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
>>  	size_t len;
>>  	struct blk_plug plug;
>>  
>> +	start = untagged_addr(start);
>> +
>>  	if (!madvise_behavior_valid(behavior))
>>  		return error;
>>  
>> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
>> index 01600d80ae01..78e0a88b2680 100644
>> --- a/mm/mempolicy.c
>> +++ b/mm/mempolicy.c
>> @@ -1360,6 +1360,7 @@ static long kernel_mbind(unsigned long start, unsigned long len,
>>  	int err;
>>  	unsigned short mode_flags;
>>  
>> +	start = untagged_addr(start);
>>  	mode_flags = mode & MPOL_MODE_FLAGS;
>>  	mode &= ~MPOL_MODE_FLAGS;
>>  	if (mode >= MPOL_MAX)
>> @@ -1517,6 +1518,8 @@ static int kernel_get_mempolicy(int __user *policy,
>>  	int uninitialized_var(pval);
>>  	nodemask_t nodes;
>>  
>> +	addr = untagged_addr(addr);
>> +
>>  	if (nmask != NULL && maxnode < nr_node_ids)
>>  		return -EINVAL;
>>  
>> diff --git a/mm/migrate.c b/mm/migrate.c
>> index f2ecc2855a12..d22c45cf36b2 100644
>> --- a/mm/migrate.c
>> +++ b/mm/migrate.c
>> @@ -1616,7 +1616,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
>>  			goto out_flush;
>>  		if (get_user(node, nodes + i))
>>  			goto out_flush;
>> -		addr = (unsigned long)p;
>> +		addr = (unsigned long)untagged_addr(p);
>>  
>>  		err = -ENODEV;
>>  		if (node < 0 || node >= MAX_NUMNODES)
>> diff --git a/mm/mincore.c b/mm/mincore.c
>> index c3f058bd0faf..64c322ed845c 100644
>> --- a/mm/mincore.c
>> +++ b/mm/mincore.c
>> @@ -249,6 +249,8 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
>>  	unsigned long pages;
>>  	unsigned char *tmp;
>>  
>> +	start = untagged_addr(start);
>> +
>>  	/* Check the start address: needs to be page-aligned.. */
>>  	if (start & ~PAGE_MASK)
>>  		return -EINVAL;fixup_user_fault
>> diff --git a/mm/mlock.c b/mm/mlock.c
>> index 080f3b36415b..e82609eaa428 100644
>> --- a/mm/mlock.c
>> +++ b/mm/mlock.c
>> @@ -674,6 +674,8 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla
>>  	unsigned long lock_limit;
>>  	int error = -ENOMEM;
>>  
>> +	start = untagged_addr(start);
>> +
>>  	if (!can_do_mlock())
>>  		return -EPERM;
>>  
>> @@ -735,6 +737,8 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
>>  {
>>  	int ret;
>>  
>> +	start = untagged_addr(start);
>> +
>>  	len = PAGE_ALIGN(len + (offset_in_page(start)));
>>  	start &= PAGE_MASK;
>>  
>> diff --git a/mm/mprotect.c b/mm/mprotect.c
>> index bf38dfbbb4b4..19f981b733bc 100644
>> --- a/mm/mprotect.c
>> +++ b/mm/mprotect.c
>> @@ -465,6 +465,8 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
>>  	const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
>>  				(prot & PROT_READ);
>>  
>> +	start = untagged_addr(start);
>> +
>>  	prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
>>  	if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
>>  		return -EINVAL;
>> diff --git a/mm/mremap.c b/mm/mremap.c
>> index fc241d23cd97..64c9a3b8be0a 100644
>> --- a/mm/mremap.c
>> +++ b/mm/mremap.c
>> @@ -606,6 +606,13 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
>>  	LIST_HEAD(uf_unmap_early);
>>  	LIST_HEAD(uf_unmap);
>>  
>> +	/*
>> +	 * Architectures may interpret the tag passed to mmap as a background
>> +	 * colour for the corresponding vma. For mremap we don't allow tagged
>> +	 * new_addr to preserve similar behaviour to mmap.
>> +	 */
>> +	addr = untagged_addr(addr);
>> +
>>  	if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
>>  		return ret;
>>  
>> diff --git a/mm/msync.c b/mm/msync.c
>> index ef30a429623a..c3bd3e75f687 100644
>> --- a/mm/msync.c
>> +++ b/mm/msync.c
>> @@ -37,6 +37,8 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
>>  	int unmapped_error = 0;
>>  	int error = -EINVAL;
>>  
>> +	start = untagged_addr(start);
>> +
>>  	if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
>>  		goto out;
>>  	if (offset_in_page(start))
>>
> 
> 



^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames
  2019-06-12 11:43 ` [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames Andrey Konovalov
  2019-06-12 14:34   ` Vincenzo Frascino
@ 2019-06-19 16:48   ` Khalid Aziz
  1 sibling, 0 replies; 51+ messages in thread
From: Khalid Aziz @ 2019-06-19 16:48 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 6/12/19 5:43 AM, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> get_vaddr_frames uses provided user pointers for vma lookups, which can
> only by done with untagged pointers. Instead of locating and changing
> all callers of this function, perform untagging in it.
> 
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---

With the suggested change to commit log in my previous email:

Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>

>  mm/frame_vector.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/mm/frame_vector.c b/mm/frame_vector.c
> index c64dca6e27c2..c431ca81dad5 100644
> --- a/mm/frame_vector.c
> +++ b/mm/frame_vector.c
> @@ -46,6 +46,8 @@ int get_vaddr_frames(unsigned long start, unsigned int nr_frames,
>  	if (WARN_ON_ONCE(nr_frames > vec->nr_allocated))
>  		nr_frames = vec->nr_allocated;
>  
> +	start = untagged_addr(start);
> +
>  	down_read(&mm->mmap_sem);
>  	locked = 1;
>  	vma = find_vma_intersection(mm, start, start + 1);
> 



^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options
  2019-06-12 11:43 ` [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
  2019-06-12 14:35   ` Vincenzo Frascino
@ 2019-06-19 20:01   ` Khalid Aziz
  1 sibling, 0 replies; 51+ messages in thread
From: Khalid Aziz @ 2019-06-19 20:01 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On 6/12/19 5:43 AM, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> In copy_mount_options a user address is being subtracted from TASK_SIZE.
> If the address is lower than TASK_SIZE, the size is calculated to not
> allow the exact_copy_from_user() call to cross TASK_SIZE boundary.
> However if the address is tagged, then the size will be calculated
> incorrectly.
> 
> Untag the address before subtracting.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---

Please update commit log to make it not arm64 specific since this change
affects other architectures as well. Other than that,

Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>


>  fs/namespace.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/namespace.c b/fs/namespace.c
> index b26778bdc236..2e85712a19ed 100644
> --- a/fs/namespace.c
> +++ b/fs/namespace.c
> @@ -2993,7 +2993,7 @@ void *copy_mount_options(const void __user * data)
>  	 * the remainder of the page.
>  	 */
>  	/* copy_from_user cannot cross TASK_SIZE ! */
> -	size = TASK_SIZE - (unsigned long)data;
> +	size = TASK_SIZE - (unsigned long)untagged_addr(data);
>  	if (size > PAGE_SIZE)
>  		size = PAGE_SIZE;
>  
> 



^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 12/15] media/v4l2-core, arm64: untag user pointers in videobuf_dma_contig_user_get
  2019-06-12 11:43 ` [PATCH v17 12/15] media/v4l2-core, arm64: untag user pointers in videobuf_dma_contig_user_get Andrey Konovalov
@ 2019-06-19 20:05   ` Khalid Aziz
  0 siblings, 0 replies; 51+ messages in thread
From: Khalid Aziz @ 2019-06-19 20:05 UTC (permalink / raw)
  To: Andrey Konovalov, linux-arm-kernel, linux-mm, linux-kernel,
	amd-gfx, dri-devel, linux-rdma, linux-media, kvm,
	linux-kselftest
  Cc: Catalin Marinas, Vincenzo Frascino, Will Deacon, Mark Rutland,
	Andrew Morton, Greg Kroah-Hartman, Kees Cook, Yishai Hadas,
	Felix Kuehling, Alexander Deucher, Christian Koenig,
	Mauro Carvalho Chehab, Jens Wiklander, Alex Williamson,
	Leon Romanovsky, Luc Van Oostenryck, Dave Martin, enh,
	Jason Gunthorpe, Christoph Hellwig, Dmitry Vyukov,
	Kostya Serebryany, Evgeniy Stepanov, Lee Smith,
	Ramana Radhakrishnan, Jacob Bramley, Ruben Ayrapetyan,
	Robin Murphy, Kevin Brodsky, Szabolcs Nagy,
	Mauro Carvalho Chehab

On 6/12/19 5:43 AM, Andrey Konovalov wrote:
> This patch is a part of a series that extends arm64 kernel ABI to allow to
> pass tagged user pointers (with the top byte set to something else other
> than 0x00) as syscall arguments.
> 
> videobuf_dma_contig_user_get() uses provided user pointers for vma
> lookups, which can only by done with untagged pointers.
> 
> Untag the pointers in this function.
> 
> Reviewed-by: Kees Cook <keescook@chromium.org>
> Acked-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> ---

Patch looks good, but commit log should be updated to not be specific to
arm64.

Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>



>  drivers/media/v4l2-core/videobuf-dma-contig.c | 9 +++++----
>  1 file changed, 5 insertions(+), 4 deletions(-)
> exact_copy_from_user
> diff --git a/drivers/media/v4l2-core/videobuf-dma-contig.c b/drivers/media/v4l2-core/videobuf-dma-contig.c
> index e1bf50df4c70..8a1ddd146b17 100644
> --- a/drivers/media/v4l2-core/videobuf-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf-dma-contig.c
> @@ -160,6 +160,7 @@ static void videobuf_dma_contig_user_put(struct videobuf_dma_contig_memory *mem)
>  static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
>  					struct videobuf_buffer *vb)
>  {
> +	unsigned long untagged_baddr = untagged_addr(vb->baddr);
>  	struct mm_struct *mm = current->mm;
>  	struct vm_area_struct *vma;
>  	unsigned long prev_pfn, this_pfn;
> @@ -167,22 +168,22 @@ static int videobuf_dma_contig_user_get(struct videobuf_dma_contig_memory *mem,
>  	unsigned int offset;
>  	int ret;
>  
> -	offset = vb->baddr & ~PAGE_MASK;
> +	offset = untagged_baddr & ~PAGE_MASK;
>  	mem->size = PAGE_ALIGN(vb->size + offset);
>  	ret = -EINVAL;
>  
>  	down_read(&mm->mmap_sem);
>  
> -	vma = find_vma(mm, vb->baddr);
> +	vma = find_vma(mm, untagged_baddr);
>  	if (!vma)
>  		goto out_up;
>  
> -	if ((vb->baddr + mem->size) > vma->vm_end)
> +	if ((untagged_baddr + mem->size) > vma->vm_end)
>  		goto out_up;
>  
>  	pages_done = 0;
>  	prev_pfn = 0; /* kill warning */
> -	user_address = vb->baddr;
> +	user_address = untagged_baddr;
>  
>  	while (pages_done < (mem->size >> PAGE_SHIFT)) {
>  		ret = follow_pfn(vma, user_address, &this_pfn);
> 



^ permalink raw reply	[flat|nested] 51+ messages in thread

* Re: [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls
  2019-06-19 16:46     ` Khalid Aziz
@ 2019-06-24 14:22       ` Andrey Konovalov
  0 siblings, 0 replies; 51+ messages in thread
From: Andrey Konovalov @ 2019-06-24 14:22 UTC (permalink / raw)
  To: Khalid Aziz
  Cc: Linux ARM, Linux Memory Management List, LKML, amd-gfx,
	dri-devel, linux-rdma, linux-media, kvm,
	open list:KERNEL SELFTEST FRAMEWORK, Catalin Marinas,
	Vincenzo Frascino, Will Deacon, Mark Rutland, Andrew Morton,
	Greg Kroah-Hartman, Kees Cook, Yishai Hadas, Felix Kuehling,
	Alexander Deucher, Christian Koenig, Mauro Carvalho Chehab,
	Jens Wiklander, Alex Williamson, Leon Romanovsky,
	Luc Van Oostenryck, Dave Martin, enh, Jason Gunthorpe,
	Christoph Hellwig, Dmitry Vyukov, Kostya Serebryany,
	Evgeniy Stepanov, Lee Smith, Ramana Radhakrishnan, Jacob Bramley,
	Ruben Ayrapetyan, Robin Murphy, Kevin Brodsky, Szabolcs Nagy

On Wed, Jun 19, 2019 at 6:46 PM Khalid Aziz <khalid.aziz@oracle.com> wrote:
>
> On 6/19/19 9:55 AM, Khalid Aziz wrote:
> > On 6/12/19 5:43 AM, Andrey Konovalov wrote:
> >> This patch is a part of a series that extends arm64 kernel ABI to allow to
> >> pass tagged user pointers (with the top byte set to something else other
> >> than 0x00) as syscall arguments.
> >>
> >> This patch allows tagged pointers to be passed to the following memory
> >> syscalls: get_mempolicy, madvise, mbind, mincore, mlock, mlock2, mprotect,
> >> mremap, msync, munlock, move_pages.
> >>
> >> The mmap and mremap syscalls do not currently accept tagged addresses.
> >> Architectures may interpret the tag as a background colour for the
> >> corresponding vma.
> >>
> >> Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
> >> Reviewed-by: Kees Cook <keescook@chromium.org>
> >> Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
> >> ---
> >
> > Reviewed-by: Khalid Aziz <khalid.aziz@oracle.com>
> >
> >
>
> I would also recommend updating commit log for all the patches in this
> series that are changing files under mm/ as opposed to arch/arm64 to not
> reference arm64 kernel ABI since the change applies to every
> architecture. So something along the lines of "This patch is part of a
> series that extends kernel ABI to allow......."

Sure, will do in v18, thanks!

>
> --
> Khalid
>
>
> >>  mm/madvise.c   | 2 ++
> >>  mm/mempolicy.c | 3 +++
> >>  mm/migrate.c   | 2 +-
> >>  mm/mincore.c   | 2 ++
> >>  mm/mlock.c     | 4 ++++
> >>  mm/mprotect.c  | 2 ++
> >>  mm/mremap.c    | 7 +++++++
> >>  mm/msync.c     | 2 ++
> >>  8 files changed, 23 insertions(+), 1 deletion(-)
> >>
> >> diff --git a/mm/madvise.c b/mm/madvise.c
> >> index 628022e674a7..39b82f8a698f 100644
> >> --- a/mm/madvise.c
> >> +++ b/mm/madvise.c
> >> @@ -810,6 +810,8 @@ SYSCALL_DEFINE3(madvise, unsigned long, start, size_t, len_in, int, behavior)
> >>      size_t len;
> >>      struct blk_plug plug;
> >>
> >> +    start = untagged_addr(start);
> >> +
> >>      if (!madvise_behavior_valid(behavior))
> >>              return error;
> >>
> >> diff --git a/mm/mempolicy.c b/mm/mempolicy.c
> >> index 01600d80ae01..78e0a88b2680 100644
> >> --- a/mm/mempolicy.c
> >> +++ b/mm/mempolicy.c
> >> @@ -1360,6 +1360,7 @@ static long kernel_mbind(unsigned long start, unsigned long len,
> >>      int err;
> >>      unsigned short mode_flags;
> >>
> >> +    start = untagged_addr(start);
> >>      mode_flags = mode & MPOL_MODE_FLAGS;
> >>      mode &= ~MPOL_MODE_FLAGS;
> >>      if (mode >= MPOL_MAX)
> >> @@ -1517,6 +1518,8 @@ static int kernel_get_mempolicy(int __user *policy,
> >>      int uninitialized_var(pval);
> >>      nodemask_t nodes;
> >>
> >> +    addr = untagged_addr(addr);
> >> +
> >>      if (nmask != NULL && maxnode < nr_node_ids)
> >>              return -EINVAL;
> >>
> >> diff --git a/mm/migrate.c b/mm/migrate.c
> >> index f2ecc2855a12..d22c45cf36b2 100644
> >> --- a/mm/migrate.c
> >> +++ b/mm/migrate.c
> >> @@ -1616,7 +1616,7 @@ static int do_pages_move(struct mm_struct *mm, nodemask_t task_nodes,
> >>                      goto out_flush;
> >>              if (get_user(node, nodes + i))
> >>                      goto out_flush;
> >> -            addr = (unsigned long)p;
> >> +            addr = (unsigned long)untagged_addr(p);
> >>
> >>              err = -ENODEV;
> >>              if (node < 0 || node >= MAX_NUMNODES)
> >> diff --git a/mm/mincore.c b/mm/mincore.c
> >> index c3f058bd0faf..64c322ed845c 100644
> >> --- a/mm/mincore.c
> >> +++ b/mm/mincore.c
> >> @@ -249,6 +249,8 @@ SYSCALL_DEFINE3(mincore, unsigned long, start, size_t, len,
> >>      unsigned long pages;
> >>      unsigned char *tmp;
> >>
> >> +    start = untagged_addr(start);
> >> +
> >>      /* Check the start address: needs to be page-aligned.. */
> >>      if (start & ~PAGE_MASK)
> >>              return -EINVAL;fixup_user_fault
> >> diff --git a/mm/mlock.c b/mm/mlock.c
> >> index 080f3b36415b..e82609eaa428 100644
> >> --- a/mm/mlock.c
> >> +++ b/mm/mlock.c
> >> @@ -674,6 +674,8 @@ static __must_check int do_mlock(unsigned long start, size_t len, vm_flags_t fla
> >>      unsigned long lock_limit;
> >>      int error = -ENOMEM;
> >>
> >> +    start = untagged_addr(start);
> >> +
> >>      if (!can_do_mlock())
> >>              return -EPERM;
> >>
> >> @@ -735,6 +737,8 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
> >>  {
> >>      int ret;
> >>
> >> +    start = untagged_addr(start);
> >> +
> >>      len = PAGE_ALIGN(len + (offset_in_page(start)));
> >>      start &= PAGE_MASK;
> >>
> >> diff --git a/mm/mprotect.c b/mm/mprotect.c
> >> index bf38dfbbb4b4..19f981b733bc 100644
> >> --- a/mm/mprotect.c
> >> +++ b/mm/mprotect.c
> >> @@ -465,6 +465,8 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
> >>      const bool rier = (current->personality & READ_IMPLIES_EXEC) &&
> >>                              (prot & PROT_READ);
> >>
> >> +    start = untagged_addr(start);
> >> +
> >>      prot &= ~(PROT_GROWSDOWN|PROT_GROWSUP);
> >>      if (grows == (PROT_GROWSDOWN|PROT_GROWSUP)) /* can't be both */
> >>              return -EINVAL;
> >> diff --git a/mm/mremap.c b/mm/mremap.c
> >> index fc241d23cd97..64c9a3b8be0a 100644
> >> --- a/mm/mremap.c
> >> +++ b/mm/mremap.c
> >> @@ -606,6 +606,13 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
> >>      LIST_HEAD(uf_unmap_early);
> >>      LIST_HEAD(uf_unmap);
> >>
> >> +    /*
> >> +     * Architectures may interpret the tag passed to mmap as a background
> >> +     * colour for the corresponding vma. For mremap we don't allow tagged
> >> +     * new_addr to preserve similar behaviour to mmap.
> >> +     */
> >> +    addr = untagged_addr(addr);
> >> +
> >>      if (flags & ~(MREMAP_FIXED | MREMAP_MAYMOVE))
> >>              return ret;
> >>
> >> diff --git a/mm/msync.c b/mm/msync.c
> >> index ef30a429623a..c3bd3e75f687 100644
> >> --- a/mm/msync.c
> >> +++ b/mm/msync.c
> >> @@ -37,6 +37,8 @@ SYSCALL_DEFINE3(msync, unsigned long, start, size_t, len, int, flags)
> >>      int unmapped_error = 0;
> >>      int error = -EINVAL;
> >>
> >> +    start = untagged_addr(start);
> >> +
> >>      if (flags & ~(MS_ASYNC | MS_INVALIDATE | MS_SYNC))
> >>              goto out;
> >>      if (offset_in_page(start))
> >>
> >
> >
>
>

^ permalink raw reply	[flat|nested] 51+ messages in thread

end of thread, back to index

Thread overview: 51+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-06-12 11:43 [PATCH v17 00/15] arm64: untag user pointers passed to the kernel Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 01/15] arm64: untag user pointers in access_ok and __uaccess_mask_ptr Andrey Konovalov
2019-06-12 14:26   ` Vincenzo Frascino
2019-06-12 11:43 ` [PATCH v17 02/15] lib, arm64: untag user pointers in strn*_user Andrey Konovalov
2019-06-12 14:28   ` Vincenzo Frascino
2019-06-12 11:43 ` [PATCH v17 03/15] arm64: Introduce prctl() options to control the tagged user addresses ABI Andrey Konovalov
2019-06-12 14:30   ` Vincenzo Frascino
2019-06-12 14:55   ` Catalin Marinas
2019-06-13 11:02   ` Dave Martin
2019-06-13 15:26     ` Catalin Marinas
2019-06-14  5:13       ` Kees Cook
2019-06-18  9:18         ` Dave Martin
2019-06-13 11:16   ` Dave Martin
2019-06-13 15:35     ` Catalin Marinas
2019-06-13 15:45       ` Vincenzo Frascino
2019-06-13 15:57         ` Catalin Marinas
2019-06-13 16:15           ` Vincenzo Frascino
2019-06-17 13:56   ` Catalin Marinas
2019-06-17 16:56     ` Szabolcs Nagy
2019-06-17 16:57     ` Evgenii Stepanov
2019-06-17 17:18       ` Catalin Marinas
2019-06-17 21:59         ` Evgenii Stepanov
2019-06-19 14:45   ` Andrey Konovalov
2019-06-19 15:29     ` Catalin Marinas
2019-06-12 11:43 ` [PATCH v17 04/15] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov
2019-06-12 14:31   ` Vincenzo Frascino
2019-06-19 15:55   ` Khalid Aziz
2019-06-19 16:46     ` Khalid Aziz
2019-06-24 14:22       ` Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 05/15] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
2019-06-12 14:33   ` Vincenzo Frascino
2019-06-19 16:41   ` Khalid Aziz
2019-06-12 11:43 ` [PATCH v17 06/15] mm, arm64: untag user pointers in get_vaddr_frames Andrey Konovalov
2019-06-12 14:34   ` Vincenzo Frascino
2019-06-19 16:48   ` Khalid Aziz
2019-06-12 11:43 ` [PATCH v17 07/15] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
2019-06-12 14:35   ` Vincenzo Frascino
2019-06-19 20:01   ` Khalid Aziz
2019-06-12 11:43 ` [PATCH v17 08/15] userfaultfd, arm64: untag user pointers Andrey Konovalov
2019-06-12 14:40   ` Vincenzo Frascino
2019-06-12 11:43 ` [PATCH v17 09/15] drm/amdgpu, " Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 10/15] drm/radeon, arm64: untag user pointers in radeon_gem_userptr_ioctl Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 11/15] IB/mlx4, arm64: untag user pointers in mlx4_get_umem_mr Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 12/15] media/v4l2-core, arm64: untag user pointers in videobuf_dma_contig_user_get Andrey Konovalov
2019-06-19 20:05   ` Khalid Aziz
2019-06-12 11:43 ` [PATCH v17 13/15] tee/shm, arm64: untag user pointers in tee_shm_register Andrey Konovalov
2019-06-12 11:43 ` [PATCH v17 14/15] vfio/type1, arm64: untag user pointers in vaddr_get_pfn Andrey Konovalov
2019-06-12 14:41   ` Vincenzo Frascino
2019-06-12 15:58   ` Auger Eric
2019-06-12 11:43 ` [PATCH v17 15/15] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2019-06-12 12:30   ` Szabolcs Nagy

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