diff options
| author | Willem de Bruijn <willemb@google.com> | 2017-02-07 21:57:21 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-02-08 19:56:37 +0100 |
| commit | 57031eb794906eea4e1c7b31dc1e2429c0af0c66 (patch) | |
| tree | ffe0e21da8d4ae2b435561434cc391970196e42b /net/packet | |
| parent | net: introduce device min_header_len (diff) | |
| download | linux-57031eb794906eea4e1c7b31dc1e2429c0af0c66.tar.xz linux-57031eb794906eea4e1c7b31dc1e2429c0af0c66.zip | |
packet: round up linear to header len
Link layer protocols may unconditionally pull headers, as Ethernet
does in eth_type_trans. Ensure that the entire link layer header
always lies in the skb linear segment. tpacket_snd has such a check.
Extend this to packet_snd.
Variable length link layer headers complicate the computation
somewhat. Here skb->len may be smaller than dev->hard_header_len.
Round up the linear length to be at least as long as the smallest of
the two.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet')
| -rw-r--r-- | net/packet/af_packet.c | 7 |
1 files changed, 4 insertions, 3 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 3d555c79a7b5..d56ee46b11fc 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2755,7 +2755,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) struct virtio_net_hdr vnet_hdr = { 0 }; int offset = 0; struct packet_sock *po = pkt_sk(sk); - int hlen, tlen; + int hlen, tlen, linear; int extra_len = 0; /* @@ -2816,8 +2816,9 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len) err = -ENOBUFS; hlen = LL_RESERVED_SPACE(dev); tlen = dev->needed_tailroom; - skb = packet_alloc_skb(sk, hlen + tlen, hlen, len, - __virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len), + linear = __virtio16_to_cpu(vio_le(), vnet_hdr.hdr_len); + linear = max(linear, min_t(int, len, dev->hard_header_len)); + skb = packet_alloc_skb(sk, hlen + tlen, hlen, len, linear, msg->msg_flags & MSG_DONTWAIT, &err); if (skb == NULL) goto out_unlock; |