netdev - [PATCH net] net/smc: fix refcount non-blocking connect() -part 2

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Message-Id: <20191112150341.90681-1-kgraul@linux.ibm.com>
Date:   Tue, 12 Nov 2019 16:03:41 +0100
From:   Karsten Graul <kgraul@...ux.ibm.com>
To:     davem@...emloft.net
Cc:     netdev@...r.kernel.org, linux-s390@...r.kernel.org,
        heiko.carstens@...ibm.com, raspl@...ux.ibm.com,
        ubraun@...ux.ibm.com
Subject: [PATCH net] net/smc: fix refcount non-blocking connect() -part 2

From: Ursula Braun <ubraun@...ux.ibm.com>

If an SMC socket is immediately terminated after a non-blocking connect()
has been called, a memory leak is possible.
Due to the sock_hold move in
commit 301428ea3708 ("net/smc: fix refcounting for non-blocking connect()")
an extra sock_put() is needed in smc_connect_work(), if the internal
TCP socket is aborted and cancels the sk_stream_wait_connect() of the
connect worker.

Reported-by: syzbot+4b73ad6fc767e576e275@...kaller.appspotmail.com
Fixes: 301428ea3708 ("net/smc: fix refcounting for non-blocking connect()")
Signed-off-by: Ursula Braun <ubraun@...ux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@...ux.ibm.com>
---
 net/smc/af_smc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index cde4dc0ed173..d0271bcb2191 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -799,6 +799,7 @@ static void smc_connect_work(struct work_struct *work)
 			smc->sk.sk_err = EPIPE;
 		else if (signal_pending(current))
 			smc->sk.sk_err = -sock_intr_errno(timeo);
+		sock_put(&smc->sk); /* passive closing */
 		goto out;
 	}
 
-- 
2.17.1