From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefano Brivio Subject: Re: [PATCH net 1/4] net/smc: take sock lock in smc_ioctl() Date: Mon, 16 Jul 2018 12:09:15 +0200 Message-ID: <20180716120915.09d35dc0@epycfail> References: <20180716100101.79272-1-ubraun@linux.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-s390@vger.kernel.org, schwidefsky@de.ibm.com, heiko.carstens@de.ibm.com, raspl@linux.ibm.com, linux-kernel@vger.kernel.org, eric.dumazet@gmail.com, lifeasageek@gmail.com To: Ursula Braun Return-path: In-Reply-To: <20180716100101.79272-1-ubraun@linux.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Mon, 16 Jul 2018 12:01:01 +0200 Ursula Braun wrote: > From: Ursula Braun > > SMC ioctl processing requires the sock lock to work properly in > all thinkable scenarios. > Problem has been found with RaceFuzzer and fixes: > KASAN: null-ptr-deref Read in smc_ioctl > > Reported-by: Byoungyoung Lee > Reported-by: syzbot+35b2c5aa76fd398b9fd4@syzkaller.appspotmail.com > Signed-off-by: Ursula Braun > --- > net/smc/af_smc.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c > index 5334157f5065..a4381b38a521 100644 > --- a/net/smc/af_smc.c > +++ b/net/smc/af_smc.c > @@ -1524,6 +1524,7 @@ static int smc_ioctl(struct socket *sock, unsigned int cmd, > return -EBADF; > return smc->clcsock->ops->ioctl(smc->clcsock, cmd, arg); > } > + lock_sock(&smc->sk); > switch (cmd) { > case SIOCINQ: /* same as FIONREAD */ > if (smc->sk.sk_state == SMC_LISTEN) return -EINVAL; you should also unlock here, and: case SIOCOUTQ: /* output queue size (not send + not acked) */ if (smc->sk.sk_state == SMC_LISTEN) return -EINVAL; here, and: case SIOCOUTQNSD: /* output queue size (not send only) */ if (smc->sk.sk_state == SMC_LISTEN) return -EINVAL; here, and: case SIOCATMARK: if (smc->sk.sk_state == SMC_LISTEN) return -EINVAL; here. -- Stefano