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authorEric Dumazet <edumazet@google.com>2015-10-09 11:29:32 -0700
committerDavid S. Miller <davem@davemloft.net>2015-10-12 19:42:38 -0700
commit161642e24fee40fba2c5bc2ceacc00d118a22d65 (patch)
tree41342a8fa391439d545b19145c23b33af9416a6d /net/packet
parent991659674288dba28c2f5a3d1a0133ef4d20824a (diff)
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packet: fix match_fanout_group()
Recent TCP listener patches exposed a prior af_packet bug : match_fanout_group() blindly assumes it is always safe to cast sk to a packet socket to compare fanout with af_packet_priv But SYNACK packets can be sent while attached to request_sock, which are smaller than a "struct sock". We can read non existent memory and crash. Fixes: c0de08d04215 ("af_packet: don't emit packet on orig fanout group") Fixes: ca6fb0651883 ("tcp: attach SYNACK messages to request sockets instead of listener") Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Willem de Bruijn <willemb@google.com> Cc: Eric Leblond <eric@regit.org> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/packet')
-rw-r--r--net/packet/af_packet.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index 20c44e2e1e4e..396b3f1e7cc0 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -1519,10 +1519,10 @@ static void __fanout_unlink(struct sock *sk, struct packet_sock *po)
static bool match_fanout_group(struct packet_type *ptype, struct sock *sk)
{
- if (ptype->af_packet_priv == (void *)((struct packet_sock *)sk)->fanout)
- return true;
+ if (sk->sk_family != PF_PACKET)
+ return false;
- return false;
+ return ptype->af_packet_priv == pkt_sk(sk)->fanout;
}
static void fanout_init_data(struct packet_fanout *f)