From 5dc62fdd8383afbd2faca6b6e6ea1052b45b0124 Mon Sep 17 00:00:00 2001 From: James Hogan Date: Wed, 5 Aug 2015 16:41:37 +0100 Subject: [PATCH] MIPS: uaccess: Fix strlen_user with EVA The strlen_user() function calls __strlen_kernel_asm in both branches of the eva_kernel_access() conditional. For EVA it should be calling __strlen_user_eva for user accesses, otherwise it will load from the kernel address space instead of the user address space, and the access checking will likely be ineffective at preventing it due to EVA's overlapping user and kernel address spaces. This was found after extending the test_user_copy module to cover user string access functions, which gave the following error with EVA: test_user_copy: illegal strlen_user passed Fortunately the use of strlen_user() has been all but eradicated from the mainline kernel, so only out of tree modules could be affected. Fixes: e3a9b07a9caf ("MIPS: asm: uaccess: Add EVA support for str*_user operations") Signed-off-by: James Hogan Cc: Markos Chandras Cc: Paul Burton Cc: Leonid Yegoshin Cc: linux-mips@linux-mips.org Cc: # 3.15.x- Patchwork: https://patchwork.linux-mips.org/patch/10842/ Signed-off-by: Ralf Baechle --- arch/mips/include/asm/uaccess.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/mips/include/asm/uaccess.h b/arch/mips/include/asm/uaccess.h index 5305d694ffe5..3f959c01bfdb 100644 --- a/arch/mips/include/asm/uaccess.h +++ b/arch/mips/include/asm/uaccess.h @@ -1384,7 +1384,7 @@ static inline long strlen_user(const char __user *s) might_fault(); __asm__ __volatile__( "move\t$4, %1\n\t" - __MODULE_JAL(__strlen_kernel_asm) + __MODULE_JAL(__strlen_user_asm) "move\t%0, $2" : "=r" (res) : "r" (s) -- 2.20.1