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authorWillem de Bruijn <willemb@google.com>2017-02-07 15:57:21 -0500
committerDavid S. Miller <davem@davemloft.net>2017-02-08 13:56:37 -0500
commit57031eb794906eea4e1c7b31dc1e2429c0af0c66 (patch)
treeffe0e21da8d4ae2b435561434cc391970196e42b /net/packet/af_packet.c
parent217e6fa24ce28ec87fca8da93c9016cb78028612 (diff)
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/af_packet.c')
-rw-r--r--net/packet/af_packet.c7
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;