From: Andrey Konovalov <andreyknvl@google.com>
To: Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will.deacon@arm.com>,
Mark Rutland <mark.rutland@arm.com>,
Robin Murphy <robin.murphy@arm.com>,
Kees Cook <keescook@chromium.org>,
Kate Stewart <kstewart@linuxfoundation.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Ingo Molnar <mingo@kernel.org>,
"Kirill A . Shutemov" <kirill.shutemov@linux.intel.com>,
Shuah Khan <shuah@kernel.org>,
Vincenzo Frascino <vincenzo.frascino@arm.com>,
Eric Dumazet <edumazet@google.com>,
"David S. Miller" <davem@davemloft.net>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Steven Rostedt <rostedt@goodmis.org>,
Ingo Molnar <mingo@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org,
linux-mm@kvack.org, linux-arch@vger.kernel.org,
netdev@vger.kernel.org, bpf@vger.kernel.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Dmitry Vyukov <dvyukov@google.com>,
Kostya Serebryany <kcc@google.com>,
Evgeniy Stepanov <eugenis@google.com>,
Lee Smith <Lee.Smith@arm.com>,
Ramana Radhakrishnan <Ramana.Radhakrishnan@arm.com>,
Jacob Bramley <Jacob.Bramley@arm.com>,
Ruben Ayrapetyan <Ruben.Ayrapetyan@arm.com>,
Chintan Pandya <cpandya@codeaurora.org>,
Luc Van Oostenryck <luc.vanoostenryck@gmail.com>,
Dave Martin <Dave.Martin@arm.com>,
Kevin Brodsky <kevin.brodsky@arm.com>,
Szabolcs Nagy <Szabolcs.Nagy@arm.com>,
Andrey Konovalov <andreyknvl@google.com>
Subject: [PATCH v12 02/13] arm64: untag user pointers in access_ok and __uaccess_mask_ptr
Date: Mon, 18 Mar 2019 18:17:34 +0100 [thread overview]
Message-ID: <f7b263a20223da2b8b26f6a5b0d84a575af28010.1552929301.git.andreyknvl@google.com> (raw)
In-Reply-To: <cover.1552929301.git.andreyknvl@google.com>
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: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
arch/arm64/include/asm/uaccess.h | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h
index e5d5f31c6d36..9164ecb5feca 100644
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -94,7 +94,7 @@ static inline unsigned long __range_ok(const void __user *addr, unsigned long si
return ret;
}
-#define access_ok(addr, size) __range_ok(addr, size)
+#define access_ok(addr, size) __range_ok(untagged_addr(addr), size)
#define user_addr_max get_fs
#define _ASM_EXTABLE(from, to) \
@@ -226,7 +226,8 @@ 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 +235,11 @@ 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();
--
2.21.0.225.g810b269d1ac-goog
next prev parent reply other threads:[~2019-03-18 17:19 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-18 17:17 [PATCH v12 00/13] arm64: untag user pointers passed to the kernel Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 01/13] uaccess: add untagged_addr definition for other arches Andrey Konovalov
2019-03-18 17:17 ` Andrey Konovalov [this message]
2019-03-18 17:17 ` [PATCH v12 03/13] lib, arm64: untag user pointers in strn*_user Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 04/13] mm, arm64: untag user pointers passed to memory syscalls Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 05/13] mm, arm64: untag user pointers in mm/gup.c Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 06/13] fs, arm64: untag user pointers in copy_mount_options Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 07/13] fs, arm64: untag user pointers in fs/userfaultfd.c Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 08/13] net, arm64: untag user pointers in tcp_zerocopy_receive Andrey Konovalov
2019-03-18 17:35 ` Eric Dumazet
2019-03-19 16:14 ` Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 09/13] kernel, arm64: untag user pointers in prctl_set_mm* Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 10/13] tracing, arm64: untag user pointers in seq_print_user_ip Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 11/13] uprobes, arm64: untag user pointers in find_active_uprobe Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 12/13] bpf, arm64: untag user pointers in stack_map_get_build_id_offset Andrey Konovalov
2019-03-18 17:17 ` [PATCH v12 13/13] selftests, arm64: add a selftest for passing tagged pointers to kernel Andrey Konovalov
2019-03-19 18:32 ` [PATCH v12 00/13] arm64: untag user pointers passed to the kernel Andrew Morton
2019-03-20 11:25 ` Catalin Marinas
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