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| author | Al Viro <viro@zeniv.linux.org.uk> | 2016-08-18 20:54:02 -0400 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2016-09-29 11:14:32 +0200 |
| commit | ba2540d8680b26475e48bbf527eea6d70fcc1ad2 (patch) | |
| tree | 362801a9418205924bc394bc1b13a7d3ceb2792d | |
| parent | 1334047d29ad3e40fee3bb6bdb75e1707739ad01 (diff) | |
| download | lwn-ba2540d8680b26475e48bbf527eea6d70fcc1ad2.tar.gz lwn-ba2540d8680b26475e48bbf527eea6d70fcc1ad2.zip | |
frv: fix clear_user()
commit 3b8767a8f00cc6538ba6b1cf0f88502e2fd2eb90 upstream.
It should check access_ok(). Otherwise a bunch of places turn into
trivially exploitable rootholes.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -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) |