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authorDaniel Borkmann <daniel@iogearbox.net>2015-11-11 23:25:44 +0100
committerDavid S. Miller <davem@davemloft.net>2015-11-15 18:00:35 -0500
commit5cfb4c8d05b4409c4044cb9c05b19705c1d9818b (patch)
treedb5aba8f1e47af35a7557bff779b80a1a0daadbc /net
parentc72219b75fde768efccf7666342282fab7f9e4e7 (diff)
downloadlinux-5cfb4c8d05b4409c4044cb9c05b19705c1d9818b.tar.bz2
packet: fix tpacket_snd max frame len
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>
Diffstat (limited to 'net')
-rw-r--r--net/packet/af_packet.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 0066da2b8e44..242bce1cf0f3 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;