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authorAl Viro <viro@zeniv.linux.org.uk>2016-08-18 20:54:02 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2016-09-13 17:49:39 -0400
commit3b8767a8f00cc6538ba6b1cf0f88502e2fd2eb90 (patch)
treec4384793a4ee80397cd083f0f29b704eb2bdcfb6 /arch/frv
parenteb47e0293baaa3044022059f1fa9ff474bfe35cb (diff)
downloadlinux-3b8767a8f00cc6538ba6b1cf0f88502e2fd2eb90.tar.gz
linux-3b8767a8f00cc6538ba6b1cf0f88502e2fd2eb90.tar.xz
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')
-rw-r--r--arch/frv/include/asm/uaccess.h12
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)