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Subject[PATCH 4.4 118/118] ia64: copy_from_user() should zero the destination on access_ok() failure
Date
4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Al Viro <viro@zeniv.linux.org.uk>

commit a5e541f796f17228793694d64b507f5f57db4cd7 upstream.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/ia64/include/asm/uaccess.h | 20 +++++++++-----------
1 file changed, 9 insertions(+), 11 deletions(-)

--- a/arch/ia64/include/asm/uaccess.h
+++ b/arch/ia64/include/asm/uaccess.h
@@ -263,17 +263,15 @@ __copy_from_user (void *to, const void _
__cu_len; \
})

-#define copy_from_user(to, from, n) \
-({ \
- void *__cu_to = (to); \
- const void __user *__cu_from = (from); \
- long __cu_len = (n); \
- \
- __chk_user_ptr(__cu_from); \
- if (__access_ok(__cu_from, __cu_len, get_fs())) \
- __cu_len = __copy_user((__force void __user *) __cu_to, __cu_from, __cu_len); \
- __cu_len; \
-})
+static inline unsigned long
+copy_from_user(void *to, const void __user *from, unsigned long n)
+{
+ if (likely(__access_ok(from, n, get_fs())))
+ n = __copy_user((__force void __user *) to, from, n);
+ else
+ memset(to, 0, n);
+ return n;
+}

#define __copy_in_user(to, from, size) __copy_user((to), (from), (size))


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