Patch "packet: tpacket_snd(): fix signed/unsigned comparison" has been added to the 4.1-stable tree

This is a note to let you know that I've just added the patch titled

packet: tpacket_snd(): fix signed/unsigned comparison

to the 4.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
packet-tpacket_snd-fix-signed-unsigned-comparison.patch
and it can be found in the queue-4.1 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Alexander Drozdov <[email protected]>
Date: Tue, 28 Jul 2015 13:57:01 +0300
Subject: packet: tpacket_snd(): fix signed/unsigned comparison

From: Alexander Drozdov <[email protected]>

[ Upstream commit dbd46ab412b8fb395f2b0ff6f6a7eec9df311550 ]

tpacket_fill_skb() can return a negative value (-errno) which is stored in tp_len variable. In that case the following condition will be (but shouldn't be) true:

tp_len > dev->mtu + dev->hard_header_len

as dev->mtu and dev->hard_header_len are both unsigned.

That may lead to just returning an incorrect EMSGSIZE errno to the user.

---
 net/packet/af_packet.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -2307,7 +2307,8 @@ static int tpacket_snd(struct packet_soc
 		}
 		tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto,
 					  addr, hlen);
-		if (tp_len > dev->mtu + dev->hard_header_len) {
+		if (likely(tp_len >= 0) &&
+		    tp_len > dev->mtu + dev->hard_header_len) {
 			struct ethhdr *ehdr;
 			/* Earlier code assumed this would be a VLAN pkt,
 			 * double-check this now that we have the actual

Patches currently in stable-queue which might be from [email protected] are

queue-4.1/packet-tpacket_snd-fix-signed-unsigned-comparison.patch