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: v3.2.64~131
X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=12ef6094ca7ab9eb443abdc88b1ddfd3c8fae15c;hp=a57d246b8543731ba3217c06d804f83c79f5583d

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: Ben Hutchings <ben@decadent.org.uk>
---

diff --git a/net/core/iovec.c b/net/core/iovec.c
index fcf9ee7b75b3..66e3f1fad97a 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;