Commit 9117c897 authored by Willem de Bruijn's avatar Willem de Bruijn Committed by Greg Kroah-Hartman

packet: round up linear to header len

[ Upstream commit 57031eb7 ]

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: default avatarDmitry Vyukov <dvyukov@google.com>
Signed-off-by: default avatarWillem de Bruijn <willemb@google.com>
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 58691e5b
......@@ -2637,7 +2637,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
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 *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;
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment