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net/smc: fix TCP fallback socket release

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[ Upstream commit 78abe3d0df ]

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+0bf2e01269f1274b4b03@syzkaller.appspotmail.com
Reported-by: syzbot+e3132895630f957306bc@syzkaller.appspotmail.com
Signed-off-by: Myungho Jung <mhjungk@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Myungho Jung 2018-12-18 09:02:25 -08:00 committed by Greg Kroah-Hartman
parent a1bce7196b
commit e028017380
2 changed files with 16 additions and 2 deletions
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14
net/smc/af_smc.c
View file

@ -145,8 +145,14 @@ static int smc_release(struct socket *sock)
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);
}
if (smc->use_fallback) {
if (sk->sk_state != SMC_LISTEN && sk->sk_state != SMC_INIT)
@ -203,6 +209,7 @@ static struct sock *smc_sock_alloc(struct net *net, struct socket *sock,
spin_lock_init(&smc->conn.send_lock);
sk->sk_prot->hash(sk);
sk_refcnt_debug_inc(sk);
mutex_init(&smc->clcsock_release_lock);
return sk;
}
@ -818,7 +825,7 @@ static int smc_clcsock_accept(struct smc_sock *lsmc, struct smc_sock **new_smc)
struct socket *new_clcsock = NULL;
struct sock *lsk = &lsmc->sk;
struct sock *new_sk;
int rc;
int rc = -EINVAL;
release_sock(lsk);
new_sk = smc_sock_alloc(sock_net(lsk), NULL, lsk->sk_protocol);
@ -831,7 +838,10 @@ static int smc_clcsock_accept(struct smc_sock *lsmc, struct smc_sock **new_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(lsk);
if (rc < 0)
lsk->sk_err = -rc;

4
net/smc/smc.h
View file

@ -219,6 +219,10 @@ struct smc_sock { /* smc sock container */
* 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)