From: Al Viro <viro@zeniv.linux.org.uk>
Date: Fri, 19 Aug 2016 01:16:49 +0000 (-0400)
Subject: hexagon: fix strncpy_from_user() error return
X-Git-Tag: v4.4.22~15
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0be8d73a033a3fee288c8f51990213449e94b204;p=profile%2Fcommon%2Fplatform%2Fkernel%2Flinux-artik7.git

hexagon: fix strncpy_from_user() error return

commit f35c1e0671728d1c9abc405d05ef548b5fcb2fc4 upstream.

It's -EFAULT, not -1 (and contrary to the comment in there,
__strnlen_user() can return 0 - on faults).

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

diff --git a/arch/hexagon/include/asm/uaccess.h b/arch/hexagon/include/asm/uaccess.h
index f000a38..f61cfb2 100644
--- a/arch/hexagon/include/asm/uaccess.h
+++ b/arch/hexagon/include/asm/uaccess.h
@@ -103,7 +103,8 @@ static inline long hexagon_strncpy_from_user(char *dst, const char __user *src,
 {
 	long res = __strnlen_user(src, n);
 
-	/* return from strnlen can't be zero -- that would be rubbish. */
+	if (unlikely(!res))
+		return -EFAULT;
 
 	if (res > n) {
 		copy_from_user(dst, src, n);