diff options
| author | Eric Dumazet <edumazet@google.com> | 2017-04-08 08:07:33 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-05-02 21:19:53 -0700 |
| commit | 78c4e3d4848d86c1ed36181c71c9c96834e910ed (patch) | |
| tree | 6a61c0d1acef09a45b74ad29a03b7b5605cb2750 | |
| parent | 52e33b4e505dedc8708581c3dd539ded37df1c9f (diff) | |
tcp: clear saved_syn in tcp_disconnect()
[ Upstream commit 17c3060b1701fc69daedb4c90be6325d3d9fca8e ]
In the (very unlikely) case a passive socket becomes a listener,
we do not want to duplicate its saved SYN headers.
This would lead to double frees, use after free, and please hackers and
various fuzzers
Tested:
0 socket(..., SOCK_STREAM, IPPROTO_TCP) = 3
+0 setsockopt(3, IPPROTO_TCP, TCP_SAVE_SYN, [1], 4) = 0
+0 fcntl(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
+0 bind(3, ..., ...) = 0
+0 listen(3, 5) = 0
+0 < S 0:0(0) win 32972 <mss 1460,nop,wscale 7>
+0 > S. 0:0(0) ack 1 <...>
+.1 < . 1:1(0) ack 1 win 257
+0 accept(3, ..., ...) = 4
+0 connect(4, AF_UNSPEC, ...) = 0
+0 close(3) = 0
+0 bind(4, ..., ...) = 0
+0 listen(4, 5) = 0
+0 < S 0:0(0) win 32972 <mss 1460,nop,wscale 7>
+0 > S. 0:0(0) ack 1 <...>
+.1 < . 1:1(0) ack 1 win 257
Fixes: cd8ae85299d5 ("tcp: provide SYN headers for passive connections")
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>
| -rw-r--r-- | net/ipv4/tcp.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 600dcda840d1..e1d51370977b 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -2260,6 +2260,7 @@ int tcp_disconnect(struct sock *sk, int flags) tcp_init_send_head(sk); memset(&tp->rx_opt, 0, sizeof(tp->rx_opt)); __sk_dst_reset(sk); + tcp_saved_syn_free(tp); WARN_ON(inet->inet_num && !icsk->icsk_bind_hash); |