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| author | Daniel Borkmann <daniel@iogearbox.net> | 2015-11-11 23:25:44 +0100 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-12-14 12:19:23 -0500 |
| commit | 29ac1e1e04b77735383fb593a4b1d6b24f0a39e8 (patch) | |
| tree | 4a81f7c56a6f6f15808223df998df9cf7dbbad0a | |
| parent | e0bc2c24307db64d6d3d20069344d5ed93bda8ff (diff) | |
| download | lwn-29ac1e1e04b77735383fb593a4b1d6b24f0a39e8.tar.gz lwn-29ac1e1e04b77735383fb593a4b1d6b24f0a39e8.zip | |
packet: fix tpacket_snd max frame len
[ Upstream commit 5cfb4c8d05b4409c4044cb9c05b19705c1d9818b ]
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 <daniel@iogearbox.net>
Acked-by: Willem de Bruijn <willemb@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
| -rw-r--r-- | net/packet/af_packet.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c index 91f404e1052f..22853af1b6b7 100644 --- a/net/packet/af_packet.c +++ b/net/packet/af_packet.c @@ -2263,12 +2263,13 @@ 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, @@ -2292,7 +2293,7 @@ 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; |