From 90545cdc3f2b2ea700e24335610cd181e73756da Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Thu, 16 Aug 2018 21:49:07 +0200 Subject: tcp, ulp: fix leftover icsk_ulp_ops preventing sock from reattach I found that in BPF sockmap programs once we either delete a socket from the map or we updated a map slot and the old socket was purged from the map that these socket can never get reattached into a map even though their related psock has been dropped entirely at that point. Reason is that tcp_cleanup_ulp() leaves the old icsk->icsk_ulp_ops intact, so that on the next tcp_set_ulp_id() the kernel returns an -EEXIST thinking there is still some active ULP attached. BPF sockmap is the only one that has this issue as the other user, kTLS, only calls tcp_cleanup_ulp() from tcp_v4_destroy_sock() whereas sockmap semantics allow dropping the socket from the map with all related psock state being cleaned up. Fixes: 1aa12bdf1bfb ("bpf: sockmap, add sock close() hook to remove socks") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Song Liu Signed-off-by: Alexei Starovoitov --- net/ipv4/tcp_ulp.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'net/ipv4/tcp_ulp.c') diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c index 7dd44b6156c7..a5995bb2eaca 100644 --- a/net/ipv4/tcp_ulp.c +++ b/net/ipv4/tcp_ulp.c @@ -129,6 +129,8 @@ void tcp_cleanup_ulp(struct sock *sk) if (icsk->icsk_ulp_ops->release) icsk->icsk_ulp_ops->release(sk); module_put(icsk->icsk_ulp_ops->owner); + + icsk->icsk_ulp_ops = NULL; } /* Change upper layer protocol for socket */ -- cgit v1.2.3-59-g8ed1b