3.13.11-ckt32 -stable review patch. If anyone has any objections, please let me know.
------------------ From: Daniel Borkmann <[email protected]> commit 52f1454f629fafbfb47ad6727e0837250e1f08c0 upstream. Commit 57f89bfa2140 ("network: Allow af_packet to transmit +4 bytes for VLAN packets.") added the possibility for non-mmaped frames to send extra 4 byte for VLAN header so the MTU increases from 1500 to 1504 byte, for example. Commit cbd89acb9eb2 ("af_packet: fix for sending VLAN frames via packet_mmap") attempted to fix that for the mmap part but was reverted as it caused regressions while using eth_type_trans() on output path. Lets just act analogous to 57f89bfa2140 and add a similar logic to TX_RING. We presume size_max as overcharged with +4 bytes and later on after skb has been built by tpacket_fill_skb() check for ETH_P_8021Q header on packets larger than normal MTU. Can be easily reproduced with a slightly modified trafgen in mmap(2) mode, test cases: { fill(0xff, 12) const16(0x8100) fill(0xff, <1504|1505>) } { fill(0xff, 12) const16(0x0806) fill(0xff, <1500|1501>) } Note that we need to do the test right after tpacket_fill_skb() as sockets can have PACKET_LOSS set where we would not fail but instead just continue to traverse the ring. Reported-by: Mathias Kretschmer <[email protected]> Signed-off-by: Daniel Borkmann <[email protected]> Cc: Ben Greear <[email protected]> Cc: Phil Sutter <[email protected]> Tested-by: Mathias Kretschmer <[email protected]> Signed-off-by: David S. Miller <[email protected]> Signed-off-by: Kamal Mostafa <[email protected]> --- net/packet/af_packet.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index b4cb15b..870046d 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2119,8 +2119,7 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) if (unlikely(!(dev->flags & IFF_UP))) goto out_put; - reserve = dev->hard_header_len; - + reserve = dev->hard_header_len + VLAN_HLEN; size_max = po->tx_ring.frame_size - (po->tp_hdrlen - sizeof(struct sockaddr_ll)); @@ -2147,8 +2146,19 @@ static int tpacket_snd(struct packet_sock *po, struct msghdr *msg) goto out_status; tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto, - addr, hlen); + addr, hlen); + if (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 + * packet in hand. + */ + skb_reset_mac_header(skb); + ehdr = eth_hdr(skb); + if (ehdr->h_proto != htons(ETH_P_8021Q)) + tp_len = -EMSGSIZE; + } if (unlikely(tp_len < 0)) { if (po->tp_loss) { __packet_set_status(po, ph, -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
