On Wed, Nov 11, 2015 at 5:25 PM, Daniel Borkmann <dan...@iogearbox.net> wrote:
> Since it's introduction in commit 69e3c75f4d54 ("net: TX_RING and
> packet mmap"), TX_RING could be used from SOCK_DGRAM and SOCK_RAW
> side. When used with SOCK_DGRAM only, the size_max > dev->mtu +
> reserve check should have reserve as 0, but currently, this is
> unconditionally set (in it's original form as dev->hard_header_len).
>
> I think this is not correct since tpacket_fill_skb() would then
> take dev->mtu and dev->hard_header_len into account for SOCK_DGRAM,
> the extra VLAN_HLEN could be possible in both cases. Presumably, the
> reserve code was copied from packet_snd(), but later on missed the
> check. Make it similar as we have it in packet_snd().
>
> Fixes: 69e3c75f4d54 ("net: TX_RING and packet mmap")
> Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Acked-by: Willem de Bruijn <will...@google.com>
> ---
> net/packet/af_packet.c | 9 +++++----
> 1 file changed, 5 insertions(+), 4 deletions(-)
>
> diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
> index 0066da2..242bce1 100644
> --- a/net/packet/af_packet.c
> +++ b/net/packet/af_packet.c
> @@ -2510,12 +2510,13 @@ static int tpacket_snd(struct packet_sock *po, struct
> msghdr *msg)
> if (unlikely(!(dev->flags & IFF_UP)))
> goto out_put;
>
> - reserve = dev->hard_header_len + VLAN_HLEN;
> + if (po->sk.sk_socket->type == SOCK_RAW)
> + reserve = dev->hard_header_len;
> size_max = po->tx_ring.frame_size
> - (po->tp_hdrlen - sizeof(struct sockaddr_ll));
>
> - if (size_max > dev->mtu + reserve)
> - size_max = dev->mtu + reserve;
> + if (size_max > dev->mtu + reserve + VLAN_HLEN)
> + size_max = dev->mtu + reserve + VLAN_HLEN;
>
> do {
> ph = packet_current_frame(po, &po->tx_ring,
> @@ -2542,7 +2543,7 @@ static int tpacket_snd(struct packet_sock *po, struct
> msghdr *msg)
> tp_len = tpacket_fill_skb(po, skb, ph, dev, size_max, proto,
> addr, hlen);
> if (likely(tp_len >= 0) &&
> - tp_len > dev->mtu + dev->hard_header_len &&
> + tp_len > dev->mtu + reserve &&
> !packet_extra_vlan_len_allowed(dev, skb))
> tp_len = -EMSGSIZE;
>
> --
> 1.9.3
>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
