diff options
| author | Eric Dumazet <edumazet@google.com> | 2013-03-18 07:01:28 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-03-28 12:17:22 -0700 |
| commit | e2bf3e0795326990cd7fb05112e60e80833a7f75 (patch) | |
| tree | 1a668d79342c0813418715b41a811d2ee0b600b3 /net/ipv4 | |
| parent | 82e5c8b65047d5f21858436460be940dabdc9148 (diff) | |
tcp: dont handle MTU reduction on LISTEN socket
[ Upstream commit 0d4f0608619de59fd8169dd8e72aadc28d80e715 ]
When an ICMP ICMP_FRAG_NEEDED (or ICMPV6_PKT_TOOBIG) message finds a
LISTEN socket, and this socket is currently owned by the user, we
set TCP_MTU_REDUCED_DEFERRED flag in listener tsq_flags.
This is bad because if we clone the parent before it had a chance to
clear the flag, the child inherits the tsq_flags value, and next
tcp_release_cb() on the child will decrement sk_refcnt.
Result is that we might free a live TCP socket, as reported by
Dormando.
IPv4: Attempt to release TCP socket in state 1
Fix this issue by testing sk_state against TCP_LISTEN early, so that we
set TCP_MTU_REDUCED_DEFERRED on appropriate sockets (not a LISTEN one)
This bug was introduced in commit 563d34d05786
(tcp: dont drop MTU reduction indications)
Reported-by: dormando <dormando@rydia.net>
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'net/ipv4')
| -rw-r--r-- | net/ipv4/tcp_ipv4.c | 14 |
1 files changed, 7 insertions, 7 deletions
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c index eadb693eef5..d9130a98436 100644 --- a/net/ipv4/tcp_ipv4.c +++ b/net/ipv4/tcp_ipv4.c @@ -274,13 +274,6 @@ static void tcp_v4_mtu_reduced(struct sock *sk) struct inet_sock *inet = inet_sk(sk); u32 mtu = tcp_sk(sk)->mtu_info; - /* We are not interested in TCP_LISTEN and open_requests (SYN-ACKs - * send out by Linux are always <576bytes so they should go through - * unfragmented). - */ - if (sk->sk_state == TCP_LISTEN) - return; - dst = inet_csk_update_pmtu(sk, mtu); if (!dst) return; @@ -408,6 +401,13 @@ void tcp_v4_err(struct sk_buff *icmp_skb, u32 info) goto out; if (code == ICMP_FRAG_NEEDED) { /* PMTU discovery (RFC1191) */ + /* We are not interested in TCP_LISTEN and open_requests + * (SYN-ACKs send out by Linux are always <576bytes so + * they should go through unfragmented). + */ + if (sk->sk_state == TCP_LISTEN) + goto out; + tp->mtu_info = info; if (!sock_owned_by_user(sk)) { tcp_v4_mtu_reduced(sk); |