diff options
| author | Willem de Bruijn <willemb@google.com> | 2017-02-07 15:57:21 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-02-18 15:11:43 +0100 |
| commit | 82849541895fc355de23aad2ab1615969e50896f (patch) | |
| tree | 5b96cde258a85d45913cef3b7128764f32ac6a4c /net | |
| parent | 6ebde312a8ed469172fc9694ca0c8411994d47ff (diff) | |
packet: round up linear to header len
[ Upstream commit 57031eb794906eea4e1c7b31dc1e2429c0af0c66 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net')
| -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 94e4a5941d89..458722b938c7 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2813,7 +2813,7 @@ 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; /* @@ -2874,8 +2874,9 @@ 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; |