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 <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Sat Sep 26 11:13:07 PDT 2015 From: Alexander Drozdov <al.drozdov@xxxxxxxxx> Date: Tue, 28 Jul 2015 13:57:01 +0300 Subject: packet: tpacket_snd(): fix signed/unsigned comparison From: Alexander Drozdov <al.drozdov@xxxxxxxxx> [ 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. Fixes: 52f1454f629fa ("packet: allow to transmit +4 byte in TX_RING slot for VLAN case") Signed-off-by: Alexander Drozdov <al.drozdov@xxxxxxxxx> Acked-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- net/packet/af_packet.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -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 al.drozdov@xxxxxxxxx are queue-4.1/packet-tpacket_snd-fix-signed-unsigned-comparison.patch -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html