This is a note to let you know that I've just added the patch titled
arm64: uaccess: ensure extension of access_ok() addr
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm64-uaccess-ensure-extension-of-access_ok-addr.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a06040d7a791a9177581dcf7293941bd92400856 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@xxxxxxx>
Date: Wed, 3 May 2017 16:09:35 +0100
Subject: arm64: uaccess: ensure extension of access_ok() addr
From: Mark Rutland <mark.rutland@xxxxxxx>
commit a06040d7a791a9177581dcf7293941bd92400856 upstream.
Our access_ok() simply hands its arguments over to __range_ok(), which
implicitly assummes that the addr parameter is 64 bits wide. This isn't
necessarily true for compat code, which might pass down a 32-bit address
parameter.
In these cases, we don't have a guarantee that the address has been zero
extended to 64 bits, and the upper bits of the register may contain
unknown values, potentially resulting in a suprious failure.
Avoid this by explicitly casting the addr parameter to an unsigned long
(as is done on other architectures), ensuring that the parameter is
widened appropriately.
Fixes: 0aea86a2176c ("arm64: User access library functions")
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Signed-off-by: Mark Rutland <mark.rutland@xxxxxxx>
Signed-off-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
arch/arm64/include/asm/uaccess.h | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
--- a/arch/arm64/include/asm/uaccess.h
+++ b/arch/arm64/include/asm/uaccess.h
@@ -93,11 +93,12 @@ static inline void set_fs(mm_segment_t f
*/
#define __range_ok(addr, size) \
({ \
+ unsigned long __addr = (unsigned long __force)(addr); \
unsigned long flag, roksum; \
__chk_user_ptr(addr); \
asm("adds %1, %1, %3; ccmp %1, %4, #2, cc; cset %0, ls" \
: "=&r" (flag), "=&r" (roksum) \
- : "1" (addr), "Ir" (size), \
+ : "1" (__addr), "Ir" (size), \
"r" (current_thread_info()->addr_limit) \
: "cc"); \
flag; \
Patches currently in stable-queue which might be from mark.rutland@xxxxxxx are
queue-4.9/arm64-armv8_deprecated-ensure-extension-of-addr.patch
queue-4.9/arm64-uaccess-ensure-extension-of-access_ok-addr.patch
queue-4.9/arm64-xchg-hazard-against-entire-exchange-variable.patch
queue-4.9/arm64-ensure-extension-of-smp_store_release-value.patch