[PATCH 3.12 101/119] asm-generic: make get_user() clear the destination on errors
From: Jiri Slaby <hidden>
Date: 2016-09-29 10:34:40
Also in:
lkml
Subsystem:
generic include/asm header files, the rest · Maintainers:
Arnd Bergmann, Linus Torvalds
From: Al Viro <viro@zeniv.linux.org.uk> 3.12-stable review patch. If anyone has any objections, please let me know. =============== commit 9ad18b75c2f6e4a78ce204e79f37781f8815c0fa upstream. both for access_ok() failures and for faults halfway through Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Jiri Slaby <redacted> --- include/asm-generic/uaccess.h | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-)
diff --git a/include/asm-generic/uaccess.h b/include/asm-generic/uaccess.h
index dc1269c74a52..a79424155cfe 100644
--- a/include/asm-generic/uaccess.h
+++ b/include/asm-generic/uaccess.h@@ -228,14 +228,18 @@ extern int __put_user_bad(void) __attribute__((noreturn)); might_fault(); \ access_ok(VERIFY_READ, ptr, sizeof(*ptr)) ? \ __get_user(x, ptr) : \ - -EFAULT; \ + ((x) = (__typeof__(*(ptr)))0,-EFAULT); \ }) #ifndef __get_user_fn static inline int __get_user_fn(size_t size, const void __user *ptr, void *x) { - size = __copy_from_user(x, ptr, size); - return size ? -EFAULT : size; + size_t n = __copy_from_user(x, ptr, size); + if (unlikely(n)) { + memset(x + (size - n), 0, n); + return -EFAULT; + } + return 0; } #define __get_user_fn(sz, u, k) __get_user_fn(sz, u, k)
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2.10.0