arm64: uaccess: ensure extension of access_ok() addr
authorMark Rutland <mark.rutland@arm.com>
Wed, 3 May 2017 15:09:35 +0000 (16:09 +0100)
committerCatalin Marinas <catalin.marinas@arm.com>
Tue, 9 May 2017 16:46:51 +0000 (17:46 +0100)
commita06040d7a791a9177581dcf7293941bd92400856
treed98c82e80ac702b224342b2e49072319a9545ea8
parent994870bead4ab19087a79492400a5478e2906196
arm64: uaccess: ensure extension of access_ok() addr

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")
Cc: <stable@vger.kernel.org> # 3.7.x-
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
arch/arm64/include/asm/uaccess.h