Commit 7311d665 authored Aug 08, 2018 by Ursula Braun Committed by David S. Miller Aug 08, 2018

net/smc: move sock lock in smc_ioctl()



When an SMC socket is connecting it is decided whether fallback to
TCP is needed. To avoid races between connect and ioctl move the
sock lock before the use_fallback check.

Reported-by:  <syzbot+5b2cece1a8ecb2ca77d8@syzkaller.appspotmail.com>
Reported-by:  <syzbot+19557374321ca3710990@syzkaller.appspotmail.com>
Fixes: 1992d998 ("net/smc: take sock lock in smc_ioctl()")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent bd58c7e0

net/smc/af_smc.c

+7 −3

Original line number	Diff line number	Diff line
		@@ -1522,12 +1522,16 @@ static int smc_ioctl(struct socket *sock, unsigned int cmd,

		smc = smc_sk(sock->sk);
		conn = &smc->conn;
		lock_sock(&smc->sk);
		if (smc->use_fallback) {
		if (!smc->clcsock)
		if (!smc->clcsock) {
		release_sock(&smc->sk);
		return -EBADF;
		return smc->clcsock->ops->ioctl(smc->clcsock, cmd, arg);
		}
		lock_sock(&smc->sk);
		answ = smc->clcsock->ops->ioctl(smc->clcsock, cmd, arg);
		release_sock(&smc->sk);
		return answ;
		}
		switch (cmd) {
		case SIOCINQ: /* same as FIONREAD */
		if (smc->sk.sk_state == SMC_LISTEN) {