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| author | Eric Dumazet <edumazet@google.com> | 2015-10-09 11:29:32 -0700 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-10-12 19:42:38 -0700 |
| commit | 161642e24fee40fba2c5bc2ceacc00d118a22d65 (patch) | |
| tree | 41342a8fa391439d545b19145c23b33af9416a6d /net/packet/af_packet.c | |
| parent | 991659674288dba28c2f5a3d1a0133ef4d20824a (diff) | |
| download | lwn-161642e24fee40fba2c5bc2ceacc00d118a22d65.tar.gz lwn-161642e24fee40fba2c5bc2ceacc00d118a22d65.zip | |
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/af_packet.c')
| -rw-r--r-- | net/packet/af_packet.c | 6 |
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) |