4.14-stable review patch. If anyone has any objections, please let me know.
------------------
From: Myungho Jung <mhju...@gmail.com>
[ Upstream commit 78abe3d0dfad196959b1246003366e2610775ea6 ]
clcsock can be released while kernel_accept() references it in TCP
listen worker. Also, clcsock needs to wake up before released if TCP
fallback is used and the clcsock is blocked by accept. Add a lock to
safely release clcsock and call kernel_sock_shutdown() to wake up
clcsock from accept in smc_release().
Reported-by: syzbot+0bf2e01269f1274b4...@syzkaller.appspotmail.com
Reported-by: syzbot+e3132895630f95730...@syzkaller.appspotmail.com
Signed-off-by: Myungho Jung <mhju...@gmail.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
net/smc/af_smc.c | 14 ++++++++++++--
net/smc/smc.h | 4 ++++
2 files changed, 16 insertions(+), 2 deletions(-)
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -133,8 +133,14 @@ static int smc_release(struct socket *so
sk->sk_shutdown |= SHUTDOWN_MASK;
}
if (smc->clcsock) {
+ if (smc->use_fallback && sk->sk_state == SMC_LISTEN) {
+ /* wake up clcsock accept */
+ rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
+ }
+ mutex_lock(&smc->clcsock_release_lock);
sock_release(smc->clcsock);
smc->clcsock = NULL;
+ mutex_unlock(&smc->clcsock_release_lock);
}
/* detach socket */
@@ -184,6 +190,7 @@ static struct sock *smc_sock_alloc(struc
INIT_DELAYED_WORK(&smc->sock_put_work, smc_close_sock_put_work);
sk->sk_prot->hash(sk);
sk_refcnt_debug_inc(sk);
+ mutex_init(&smc->clcsock_release_lock);
return sk;
}
@@ -577,7 +584,7 @@ static int smc_clcsock_accept(struct smc
struct sock *sk = &lsmc->sk;
struct socket *new_clcsock;
struct sock *new_sk;
- int rc;
+ int rc = -EINVAL;
release_sock(&lsmc->sk);
new_sk = smc_sock_alloc(sock_net(sk), NULL);
@@ -590,7 +597,10 @@ static int smc_clcsock_accept(struct smc
}
*new_smc = smc_sk(new_sk);
- rc = kernel_accept(lsmc->clcsock, &new_clcsock, 0);
+ mutex_lock(&lsmc->clcsock_release_lock);
+ if (lsmc->clcsock)
+ rc = kernel_accept(lsmc->clcsock, &new_clcsock, 0);
+ mutex_unlock(&lsmc->clcsock_release_lock);
lock_sock(&lsmc->sk);
if (rc < 0) {
lsmc->sk.sk_err = -rc;
--- a/net/smc/smc.h
+++ b/net/smc/smc.h
@@ -185,6 +185,10 @@ struct smc_sock { /* smc sock
contain
* started, waiting for unsent
* data to be sent
*/
+ struct mutex clcsock_release_lock;
+ /* protects clcsock of a listen
+ * socket
+ * */
};
static inline struct smc_sock *smc_sk(const struct sock *sk)
