arm64: uaccess: ensure extension of access_ok() addr

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commit a06040d7a7 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: 0aea86a217 ("arm64: User access library functions")
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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Mark Rutland 2017-05-03 16:09:35 +01:00 • committed by Greg Kroah-Hartman

parent 4775fbcc92

commit e817a7fb2f

1 changed files with 2 additions and 1 deletions

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arch/arm64/include/asm/uaccess.h

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