[PATCH v1 0/4] Fixes for MDWE prctl

[PATCH v1 0/4] Fixes for MDWE prctl

[Joey Gouly]

Hi all,

These are four small fixes for the recent memory-write-deny-execute prctl patches [1].
Two reported by Alexey about error handling and two tooling fixes by Peter.

Thanks,
Joey

[1] https://lore.kernel.org/linux-arm-kernel/20230119160344.54358-1-joey.gouly@arm.com/

Joey Gouly (2):
  mm: deduplicate error handling for map_deny_write_exec
  mm: fix error handling for map_deny_write_exec

Peter Xu (2):
  kselftest: vm: fix unused variable warning
  tools headers UAPI: Sync linux/prctl.h with the kernel sources

 mm/mmap.c                              | 7 +------
 mm/mprotect.c                          | 2 +-
 tools/include/uapi/linux/prctl.h       | 6 ++++++
 tools/testing/selftests/mm/mdwe_test.c | 3 +--
 4 files changed, 9 insertions(+), 9 deletions(-)

--
2.17.1

[PATCH v1 1/4] mm: deduplicate error handling for map_deny_write_exec

[Joey Gouly]

Commit cc8d1b097de7 ("mmap: clean up mmap_region() unrolling") deduplicated
the error handling, do the same for the return value of `map_deny_write_exec`.

Fixes: b507808ebce2 ("mm: implement memory-deny-write-execute as a prctl")
Reported-by: Alexey Izbyshev <izbyshev@ispras.ru>
Link: https://lore.kernel.org/linux-arm-kernel/8408d8901e9d7ee6b78db4c6cba04b78@ispras.ru/
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 mm/mmap.c | 7 +------
 1 file changed, 1 insertion(+), 6 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 740b54be3ed4..ad499f7b767f 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2621,12 +2621,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 
 	if (map_deny_write_exec(vma, vma->vm_flags)) {
 		error = -EACCES;
-		if (file)
-			goto close_and_free_vma;
-		else if (vma->vm_file)
-			goto unmap_and_free_vma;
-		else
-			goto free_vma;
+		goto close_and_free_vma;
 	}
 
 	/* Allow architectures to sanity-check the vm_flags */
-- 
2.17.1

[PATCH v1 2/4] mm: fix error handling for map_deny_write_exec

[Joey Gouly]

Commit 4a18419f71cd ("mm/mprotect: use mmu_gather") changed 'goto out;'
to 'break' in the loop.
This wasn't noticed while rebasing the MDWE patches, so fix it now.

Fixes: b507808ebce2 ("mm: implement memory-deny-write-execute as a prctl")
Reported-by: Alexey Izbyshev <izbyshev@ispras.ru>
Link: https://lore.kernel.org/linux-arm-kernel/8408d8901e9d7ee6b78db4c6cba04b78@ispras.ru/
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 mm/mprotect.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/mprotect.c b/mm/mprotect.c
index 231929f119d9..13e84d8c0797 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -805,7 +805,7 @@ static int do_mprotect_pkey(unsigned long start, size_t len,
 
 		if (map_deny_write_exec(vma, newflags)) {
 			error = -EACCES;
-			goto out;
+			break;
 		}
 
 		/* Allow architectures to sanity-check the new flags */
-- 
2.17.1

[PATCH v1 3/4] kselftest: vm: fix unused variable warning

[Joey Gouly]

From: Peter Xu <peterx@redhat.com>

Remove unused variable from the MDWE test.

Fixes: 4cf1fe34fd18 ("kselftest: vm: add tests for memory-deny-write-execute")
Signed-off-by: Peter Xu <peterx@redhat.com>
[joey: added commit message]
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
---
 tools/testing/selftests/mm/mdwe_test.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/tools/testing/selftests/mm/mdwe_test.c b/tools/testing/selftests/mm/mdwe_test.c
index f466a099f1bf..bc91bef5d254 100644
--- a/tools/testing/selftests/mm/mdwe_test.c
+++ b/tools/testing/selftests/mm/mdwe_test.c
@@ -163,9 +163,8 @@ TEST_F(mdwe, mprotect_WRITE_EXEC)
 
 TEST_F(mdwe, mmap_FIXED)
 {
-	void *p, *p2;
+	void *p;
 
-	p2 = mmap(NULL, self->size, PROT_READ | PROT_EXEC, self->flags, 0, 0);
 	self->p = mmap(NULL, self->size, PROT_READ, self->flags, 0, 0);
 	ASSERT_NE(self->p, MAP_FAILED);
 
-- 
2.17.1

[PATCH v1 4/4] tools headers UAPI: Sync linux/prctl.h with the kernel sources

[Joey Gouly]

From: Peter Xu <peterx@redhat.com>

Sync prctl.h after the changes in b507808ebce ("mm: implement memory-deny-write-execute as a prctl")

Fixes: 4cf1fe34fd18 ("kselftest: vm: add tests for memory-deny-write-execute")
Signed-off-by: Peter Xu <peterx@redhat.com>
[joey: added commit message]
Signed-off-by: Joey Gouly <joey.gouly@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/include/uapi/linux/prctl.h | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/include/uapi/linux/prctl.h b/tools/include/uapi/linux/prctl.h
index a5e06dcbba13..1312a137f7fb 100644
--- a/tools/include/uapi/linux/prctl.h
+++ b/tools/include/uapi/linux/prctl.h
@@ -281,6 +281,12 @@ struct prctl_mm_map {
 # define PR_SME_VL_LEN_MASK		0xffff
 # define PR_SME_VL_INHERIT		(1 << 17) /* inherit across exec */
 
+/* Memory deny write / execute */
+#define PR_SET_MDWE			65
+# define PR_MDWE_REFUSE_EXEC_GAIN	1
+
+#define PR_GET_MDWE			66
+
 #define PR_SET_VMA		0x53564d41
 # define PR_SET_VMA_ANON_NAME		0
 
-- 
2.17.1

Re: [PATCH v1 1/4] mm: deduplicate error handling for map_deny_write_exec

[Catalin Marinas]

On Wed, Mar 08, 2023 at 07:04:20PM +0000, Joey Gouly wrote:
> Commit cc8d1b097de7 ("mmap: clean up mmap_region() unrolling") deduplicated
> the error handling, do the same for the return value of `map_deny_write_exec`.
> 
> Fixes: b507808ebce2 ("mm: implement memory-deny-write-execute as a prctl")
> Reported-by: Alexey Izbyshev <izbyshev@ispras.ru>
> Link: https://lore.kernel.org/linux-arm-kernel/8408d8901e9d7ee6b78db4c6cba04b78@ispras.ru/
> Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

Re: [PATCH v1 2/4] mm: fix error handling for map_deny_write_exec

[Catalin Marinas]

On Wed, Mar 08, 2023 at 07:04:21PM +0000, Joey Gouly wrote:
> Commit 4a18419f71cd ("mm/mprotect: use mmu_gather") changed 'goto out;'
> to 'break' in the loop.
> This wasn't noticed while rebasing the MDWE patches, so fix it now.
> 
> Fixes: b507808ebce2 ("mm: implement memory-deny-write-execute as a prctl")
> Reported-by: Alexey Izbyshev <izbyshev@ispras.ru>
> Link: https://lore.kernel.org/linux-arm-kernel/8408d8901e9d7ee6b78db4c6cba04b78@ispras.ru/
> Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>

Re: [PATCH v1 3/4] kselftest: vm: fix unused variable warning

[Catalin Marinas]

On Wed, Mar 08, 2023 at 07:04:22PM +0000, Joey Gouly wrote:
> From: Peter Xu <peterx@redhat.com>
> 
> Remove unused variable from the MDWE test.
> 
> Fixes: 4cf1fe34fd18 ("kselftest: vm: add tests for memory-deny-write-execute")
> Signed-off-by: Peter Xu <peterx@redhat.com>
> [joey: added commit message]
> Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>

Re: [PATCH v1 4/4] tools headers UAPI: Sync linux/prctl.h with the kernel sources

[Catalin Marinas]

On Wed, Mar 08, 2023 at 07:04:23PM +0000, Joey Gouly wrote:
> From: Peter Xu <peterx@redhat.com>
> 
> Sync prctl.h after the changes in b507808ebce ("mm: implement memory-deny-write-execute as a prctl")
> 
> Fixes: 4cf1fe34fd18 ("kselftest: vm: add tests for memory-deny-write-execute")
> Signed-off-by: Peter Xu <peterx@redhat.com>
> [joey: added commit message]
> Signed-off-by: Joey Gouly <joey.gouly@arm.com>
> Cc: Catalin Marinas <catalin.marinas@arm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>

Acked-by: Catalin Marinas <catalin.marinas@arm.com>