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| author | Al Viro <viro@zeniv.linux.org.uk> | 2016-08-18 20:54:02 -0400 |
|---|---|---|
| committer | Al Viro <viro@zeniv.linux.org.uk> | 2016-09-13 17:49:39 -0400 |
| commit | 3b8767a8f00cc6538ba6b1cf0f88502e2fd2eb90 (patch) | |
| tree | c4384793a4ee80397cd083f0f29b704eb2bdcfb6 /arch/frv/include/asm/uaccess.h | |
| parent | eb47e0293baaa3044022059f1fa9ff474bfe35cb (diff) | |
| download | lwn-3b8767a8f00cc6538ba6b1cf0f88502e2fd2eb90.tar.gz lwn-3b8767a8f00cc6538ba6b1cf0f88502e2fd2eb90.zip | |
frv: fix clear_user()
It should check access_ok(). Otherwise a bunch of places turn into
trivially exploitable rootholes.
Cc: stable@vger.kernel.org
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'arch/frv/include/asm/uaccess.h')
| -rw-r--r-- | arch/frv/include/asm/uaccess.h | 12 |
1 files changed, 9 insertions, 3 deletions
diff --git a/arch/frv/include/asm/uaccess.h b/arch/frv/include/asm/uaccess.h index 3ac9a59d65d4..87d9e34c5df8 100644 --- a/arch/frv/include/asm/uaccess.h +++ b/arch/frv/include/asm/uaccess.h @@ -263,19 +263,25 @@ do { \ extern long __memset_user(void *dst, unsigned long count); extern long __memcpy_user(void *dst, const void *src, unsigned long count); -#define clear_user(dst,count) __memset_user(____force(dst), (count)) +#define __clear_user(dst,count) __memset_user(____force(dst), (count)) #define __copy_from_user_inatomic(to, from, n) __memcpy_user((to), ____force(from), (n)) #define __copy_to_user_inatomic(to, from, n) __memcpy_user(____force(to), (from), (n)) #else -#define clear_user(dst,count) (memset(____force(dst), 0, (count)), 0) +#define __clear_user(dst,count) (memset(____force(dst), 0, (count)), 0) #define __copy_from_user_inatomic(to, from, n) (memcpy((to), ____force(from), (n)), 0) #define __copy_to_user_inatomic(to, from, n) (memcpy(____force(to), (from), (n)), 0) #endif -#define __clear_user clear_user +static inline unsigned long __must_check +clear_user(void __user *to, unsigned long n) +{ + if (likely(__access_ok(to, n))) + n = __clear_user(to, n); + return n; +} static inline unsigned long __must_check __copy_to_user(void __user *to, const void *from, unsigned long n) |