leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity

net/smc: add fallback check to connect()

Browse Source 
FASTOPEN setsockopt() or sendmsg() may switch the SMC socket to fallback
mode. Once fallback mode is active, the native TCP socket functions are
called. Nevertheless there is a small race window, when FASTOPEN
setsockopt/sendmsg runs in parallel to a connect(), and switch the
socket into fallback mode before connect() takes the sock lock.
Make sure the SMC-specific connect setup is omitted in this case.

This way a syzbot-reported refcount problem is fixed, triggered by
different threads running non-blocking connect() and FASTOPEN_KEY
setsockopt.

Reported-by: syzbot+96d3f9ff6a86d37e44c8@syzkaller.appspotmail.com
Fixes: 6d6dd528d5 ("net/smc: fix refcount non-blocking connect() -part 2")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
This commit is contained in:
Ursula Braun 2019-12-12 22:35:58 +01:00 committed by Jakub Kicinski
parent 9b2079c046
commit 86434744fe
1 changed files with 8 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

14
net/smc/af_smc.c
View File

@ -857,6 +857,8 @@ static int smc_connect(struct socket *sock, struct sockaddr *addr,
goto out;
sock_hold(&smc->sk); /* sock put in passive closing */
if (smc->use_fallback)
goto out;
if (flags & O_NONBLOCK) {
if (schedule_work(&smc->connect_work))
smc->connect_nonblock = 1;
@ -1721,8 +1723,6 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
sk->sk_err = smc->clcsock->sk->sk_err;
sk->sk_error_report(sk);
}
if (rc)
return rc;
if (optlen < sizeof(int))
return -EINVAL;
@ -1730,6 +1730,8 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
return -EFAULT;
lock_sock(sk);
if (rc || smc->use_fallback)
goto out;
switch (optname) {
case TCP_ULP:
case TCP_FASTOPEN:
@ -1741,15 +1743,14 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
smc_switch_to_fallback(smc);
smc->fallback_rsn = SMC_CLC_DECL_OPTUNSUPP;
} else {
if (!smc->use_fallback)
rc = -EINVAL;
rc = -EINVAL;
}
break;
case TCP_NODELAY:
if (sk->sk_state != SMC_INIT &&
sk->sk_state != SMC_LISTEN &&
sk->sk_state != SMC_CLOSED) {
if (val && !smc->use_fallback)
if (val)
mod_delayed_work(system_wq, &smc->conn.tx_work,
0);
}
@ -1758,7 +1759,7 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
if (sk->sk_state != SMC_INIT &&
sk->sk_state != SMC_LISTEN &&
sk->sk_state != SMC_CLOSED) {
if (!val && !smc->use_fallback)
if (!val)
mod_delayed_work(system_wq, &smc->conn.tx_work,
0);
}
@ -1769,6 +1770,7 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
default:
break;
}
out:
release_sock(sk);
return rc;