From b79cc879e13e5be871583fa67df959066c94c028 Mon Sep 17 00:00:00 2001
From: Sasha Levin <sasha.levin@oracle.com>
Date: Thu, 31 Jul 2014 23:00:35 -0400
Subject: 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>
---
 net/core/iovec.c | 4 ++++
 1 file changed, 4 insertions(+)

(limited to 'net')

diff --git a/net/core/iovec.c b/net/core/iovec.c
index a9c46ba16718..26dc0062652f 100644
--- a/net/core/iovec.c
+++ b/net/core/iovec.c
@@ -107,6 +107,10 @@ EXPORT_SYMBOL(memcpy_toiovecend);
 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;
-- 
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