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authorTom Herbert <tom@quantonium.net>2018-03-13 12:01:43 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-31 18:11:35 +0200
commit406996f36e01b5da0685e8e205302448b29feba3 (patch)
treed56dbdbb450844fd3038d8f1948cdc68c7ee6a58
parent002f45571f6b498d417ba1dcc91bd59d386303a2 (diff)
kcm: lock lower socket in kcm_attach
[ Upstream commit 2cc683e88c0c993ac3721d9b702cb0630abe2879 ] Need to lock lower socket in order to provide mutual exclusion with kcm_unattach. v2: Add Reported-by for syzbot Fixes: ab7ac4eb9832e32a09f4e804 ("kcm: Kernel Connection Multiplexor module") Reported-by: syzbot+ea75c0ffcd353d32515f064aaebefc5279e6161e@syzkaller.appspotmail.com Signed-off-by: Tom Herbert <tom@quantonium.net> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--net/kcm/kcmsock.c33
1 files changed, 23 insertions, 10 deletions
diff --git a/net/kcm/kcmsock.c b/net/kcm/kcmsock.c
index 179cd9b1b1f4..63e6d08388ab 100644
--- a/net/kcm/kcmsock.c
+++ b/net/kcm/kcmsock.c
@@ -1375,24 +1375,32 @@ static int kcm_attach(struct socket *sock, struct socket *csock,
struct list_head *head;
int index = 0;
struct strp_callbacks cb;
- int err;
+ int err = 0;
csk = csock->sk;
if (!csk)
return -EINVAL;
+ lock_sock(csk);
+
/* Only allow TCP sockets to be attached for now */
if ((csk->sk_family != AF_INET && csk->sk_family != AF_INET6) ||
- csk->sk_protocol != IPPROTO_TCP)
- return -EOPNOTSUPP;
+ csk->sk_protocol != IPPROTO_TCP) {
+ err = -EOPNOTSUPP;
+ goto out;
+ }
/* Don't allow listeners or closed sockets */
- if (csk->sk_state == TCP_LISTEN || csk->sk_state == TCP_CLOSE)
- return -EOPNOTSUPP;
+ if (csk->sk_state == TCP_LISTEN || csk->sk_state == TCP_CLOSE) {
+ err = -EOPNOTSUPP;
+ goto out;
+ }
psock = kmem_cache_zalloc(kcm_psockp, GFP_KERNEL);
- if (!psock)
- return -ENOMEM;
+ if (!psock) {
+ err = -ENOMEM;
+ goto out;
+ }
psock->mux = mux;
psock->sk = csk;
@@ -1406,7 +1414,7 @@ static int kcm_attach(struct socket *sock, struct socket *csock,
err = strp_init(&psock->strp, csk, &cb);
if (err) {
kmem_cache_free(kcm_psockp, psock);
- return err;
+ goto out;
}
write_lock_bh(&csk->sk_callback_lock);
@@ -1418,7 +1426,8 @@ static int kcm_attach(struct socket *sock, struct socket *csock,
write_unlock_bh(&csk->sk_callback_lock);
strp_done(&psock->strp);
kmem_cache_free(kcm_psockp, psock);
- return -EALREADY;
+ err = -EALREADY;
+ goto out;
}
psock->save_data_ready = csk->sk_data_ready;
@@ -1454,7 +1463,10 @@ static int kcm_attach(struct socket *sock, struct socket *csock,
/* Schedule RX work in case there are already bytes queued */
strp_check_rcv(&psock->strp);
- return 0;
+out:
+ release_sock(csk);
+
+ return err;
}
static int kcm_attach_ioctl(struct socket *sock, struct kcm_attach *info)
@@ -1506,6 +1518,7 @@ static void kcm_unattach(struct kcm_psock *psock)
if (WARN_ON(psock->rx_kcm)) {
write_unlock_bh(&csk->sk_callback_lock);
+ release_sock(csk);
return;
}