From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Borkmann Subject: [PATCH bpf 2/5] tcp, ulp: fix leftover icsk_ulp_ops preventing sock from reattach Date: Thu, 16 Aug 2018 21:49:07 +0200 Message-ID: <20180816194910.9040-3-daniel@iogearbox.net> References: <20180816194910.9040-1-daniel@iogearbox.net> Cc: john.fastabend@gmail.com, netdev@vger.kernel.org, Daniel Borkmann To: alexei.starovoitov@gmail.com Return-path: Received: from www62.your-server.de ([213.133.104.62]:36938 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725823AbeHPWto (ORCPT ); Thu, 16 Aug 2018 18:49:44 -0400 In-Reply-To: <20180816194910.9040-1-daniel@iogearbox.net> Sender: netdev-owner@vger.kernel.org List-ID: 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 --- net/ipv4/tcp_ulp.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/net/ipv4/tcp_ulp.c b/net/ipv4/tcp_ulp.c index 7dd44b6..a5995bb 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 */ -- 2.9.5