Messages in this thread Patch in this message | | | From | Greg Kroah-Hartman <> | Subject | [PATCH 4.4 17/20] packet: round up linear to header len | Date | Thu, 16 Feb 2017 09:53:47 -0800 |
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4.4-stable review patch. If anyone has any objections, please let me know.
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From: Willem de Bruijn <willemb@google.com>
[ 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> --- net/packet/af_packet.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-)
--- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2637,7 +2637,7 @@ static int packet_snd(struct socket *soc int vnet_hdr_len; struct packet_sock *po = pkt_sk(sk); unsigned short gso_type = 0; - int hlen, tlen; + int hlen, tlen, linear; int extra_len = 0; ssize_t n; @@ -2741,8 +2741,9 @@ static int packet_snd(struct socket *soc 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;
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