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: v3.2.84~44
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d848857e80ab89474c7686d6a32d7ee594f0b706;p=pandora-kernel.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: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/arch/hexagon/include/asm/uaccess.h b/arch/hexagon/include/asm/uaccess.h
index 7e706eadbf0a..c73897c5f7b3 100644
--- a/arch/hexagon/include/asm/uaccess.h
+++ b/arch/hexagon/include/asm/uaccess.h
@@ -102,7 +102,8 @@ 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);