From: Sasha Levin <sasha.levin@oracle.com>
Date: Fri, 1 Aug 2014 03:00:35 +0000 (-0400)
Subject: iovec: make sure the caller actually wants anything in memcpy_fromiovecend
X-Git-Tag: v3.4.103~15
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8fbbef088e95f015f89cc155a02fe64017905765;p=people%2Fms%2Flinux.git

iovec: make sure the caller actually wants anything in memcpy_fromiovecend

[ Upstream commit 06ebb06d49486676272a3c030bfeef4bd969a8e6 ]

Check for cases when the caller requests 0 bytes instead of running off
and dereferencing potentially invalid iovecs.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/core/iovec.c b/net/core/iovec.c
index 4db6bfa04fbe..d1628b79286b 100644
--- a/net/core/iovec.c
+++ b/net/core/iovec.c
@@ -157,6 +157,10 @@ EXPORT_SYMBOL(memcpy_fromiovec);
 int memcpy_fromiovecend(unsigned char *kdata, const struct iovec *iov,
 			int offset, int len)
 {
+	/* No data? Done! */
+	if (len == 0)
+		return 0;
+
 	/* Skip over the finished iovecs */
 	while (offset >= iov->iov_len) {
 		offset -= iov->iov_len;