Commits
Eric Dumazet committed 17c3060b170
tcp: clear saved_syn in tcp_disconnect()
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>