From: Herbert Xu <herbert@gondor.apana.org.au>
Date: Thu, 20 Sep 2007 19:41:36 +0000 (-0700)
Subject: Fix datagram recvmsg NULL iov handling regression.
X-Git-Tag: v2.6.22.9~4
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=bbaded590e3293abbbca4d58a8fb7ad8447b2640;p=karo-tx-linux.git

Fix datagram recvmsg NULL iov handling regression.

commit ef8aef55ce61fd0e2af798695f7386ac756ae1e7 in mainline

Subject: [PATCH] [NET]: Do not dereference iov if length is zero

When msg_iovlen is zero we shouldn't try to dereference
msg_iov.  Right now the only thing that tries to do so
is skb_copy_and_csum_datagram_iovec.  Since the total
length should also be zero if msg_iovlen is zero, it's
sufficient to check the total length there and simply
return if it's zero.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
---

diff --git a/net/core/datagram.c b/net/core/datagram.c
index cb056f476126..029b93e246b4 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -450,6 +450,9 @@ int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb,
 	__wsum csum;
 	int chunk = skb->len - hlen;
 
+	if (!chunk)
+		return 0;
+
 	/* Skip filled elements.
 	 * Pretty silly, look at memcpy_toiovec, though 8)
 	 */