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authorAlexander Popov <alex.popov@linux.com>2021-02-01 11:47:19 +0300
committerJakub Kicinski <kuba@kernel.org>2021-02-02 06:54:30 +0300
commitc518adafa39f37858697ac9309c6cf1805581446 (patch)
tree3210f168d0994023031222b8cce28bc546e3137a /net/vmw_vsock/af_vsock.c
parent938e0fcd3253efdef8924714158911286d08cfe1 (diff)
downloadlinux-c518adafa39f37858697ac9309c6cf1805581446.tar.xz
vsock: fix the race conditions in multi-transport support
There are multiple similar bugs implicitly introduced by the commit c0cfa2d8a788fcf4 ("vsock: add multi-transports support") and commit 6a2c0962105ae8ce ("vsock: prevent transport modules unloading"). The bug pattern: [1] vsock_sock.transport pointer is copied to a local variable, [2] lock_sock() is called, [3] the local variable is used. VSOCK multi-transport support introduced the race condition: vsock_sock.transport value may change between [1] and [2]. Let's copy vsock_sock.transport pointer to local variables after the lock_sock() call. Fixes: c0cfa2d8a788fcf4 ("vsock: add multi-transports support") Signed-off-by: Alexander Popov <alex.popov@linux.com> Reviewed-by: Stefano Garzarella <sgarzare@redhat.com> Reviewed-by: Jorgen Hansen <jhansen@vmware.com> Link: https://lore.kernel.org/r/20210201084719.2257066-1-alex.popov@linux.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/vmw_vsock/af_vsock.c')
-rw-r--r--net/vmw_vsock/af_vsock.c17
1 files changed, 12 insertions, 5 deletions
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index b12d3a322242..6894f21dc147 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -1014,9 +1014,12 @@ static __poll_t vsock_poll(struct file *file, struct socket *sock,
mask |= EPOLLOUT | EPOLLWRNORM | EPOLLWRBAND;
} else if (sock->type == SOCK_STREAM) {
- const struct vsock_transport *transport = vsk->transport;
+ const struct vsock_transport *transport;
+
lock_sock(sk);
+ transport = vsk->transport;
+
/* Listening sockets that have connections in their accept
* queue can be read.
*/
@@ -1099,10 +1102,11 @@ static int vsock_dgram_sendmsg(struct socket *sock, struct msghdr *msg,
err = 0;
sk = sock->sk;
vsk = vsock_sk(sk);
- transport = vsk->transport;
lock_sock(sk);
+ transport = vsk->transport;
+
err = vsock_auto_bind(vsk);
if (err)
goto out;
@@ -1561,10 +1565,11 @@ static int vsock_stream_setsockopt(struct socket *sock,
err = 0;
sk = sock->sk;
vsk = vsock_sk(sk);
- transport = vsk->transport;
lock_sock(sk);
+ transport = vsk->transport;
+
switch (optname) {
case SO_VM_SOCKETS_BUFFER_SIZE:
COPY_IN(val);
@@ -1697,7 +1702,6 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg,
sk = sock->sk;
vsk = vsock_sk(sk);
- transport = vsk->transport;
total_written = 0;
err = 0;
@@ -1706,6 +1710,8 @@ static int vsock_stream_sendmsg(struct socket *sock, struct msghdr *msg,
lock_sock(sk);
+ transport = vsk->transport;
+
/* Callers should not provide a destination with stream sockets. */
if (msg->msg_namelen) {
err = sk->sk_state == TCP_ESTABLISHED ? -EISCONN : -EOPNOTSUPP;
@@ -1840,11 +1846,12 @@ vsock_stream_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
sk = sock->sk;
vsk = vsock_sk(sk);
- transport = vsk->transport;
err = 0;
lock_sock(sk);
+ transport = vsk->transport;
+
if (!transport || sk->sk_state != TCP_ESTABLISHED) {
/* Recvmsg is supposed to return 0 if a peer performs an
* orderly shutdown. Differentiate between that case and when a