From a06040d7a791a9177581dcf7293941bd92400856 Mon Sep 17 00:00:00 2001 From: Mark Rutland Date: Wed, 3 May 2017 16:09:35 +0100 Subject: 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: # 3.7.x- Acked-by: Will Deacon Signed-off-by: Mark Rutland Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/uaccess.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'arch') diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 0221029e27ff..e6540471dcda 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -95,11 +95,12 @@ static inline void set_fs(mm_segment_t fs) */ #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; \ -- cgit v1.2.3