[PATCH 4.4 113/118] nios2: copy_from_user() should zero the tail of destination
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2016-09-22 17:38:28
Also in:
lkml
4.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Al Viro <viro@zeniv.linux.org.uk> commit e33d1f6f72cc82fcfc3d1fb20c9e3ad83b1928fa upstream. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/nios2/include/asm/uaccess.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-)
--- a/arch/nios2/include/asm/uaccess.h
+++ b/arch/nios2/include/asm/uaccess.h@@ -102,9 +102,12 @@ extern long __copy_to_user(void __user * static inline long copy_from_user(void *to, const void __user *from, unsigned long n) { - if (!access_ok(VERIFY_READ, from, n)) - return n; - return __copy_from_user(to, from, n); + unsigned long res = n; + if (access_ok(VERIFY_READ, from, n)) + res = __copy_from_user(to, from, n); + if (unlikely(res)) + memset(to + (n - res), 0, res); + return res; } static inline long copy_to_user(void __user *to, const void *from,