vsock: Do not allow binding to VMADDR_PORT_ANY
commit aba0c94f61ec05315fa7815d21aefa4c87f6a9f4 upstream.
It is possible for a vsock to autobind to VMADDR_PORT_ANY. This can
cause a use-after-free when a connection is made to the bound socket.
The socket returned by accept() also has port VMADDR_PORT_ANY but is not
on the list of unbound sockets. Binding it will result in an extra
refcount decrement similar to the one fixed in fcdd2242c023 (vsock: Keep
the binding until socket destruction).
Modify the check in __vsock_bind_connectible() to also prevent binding
to VMADDR_PORT_ANY.
BUG=b/439257455
TEST=presubmit
RELEASE_NOTE=Fixed KCTF-aba0c94 in the Linux kernel.
Fixes: d021c344051a ("VSOCK: Introduce VM Sockets")
Reported-by: Budimir Markovic <markovicbudimir@gmail.com>
Change-Id: I845e7aa5cad37d7316e9e04e60a1699ae20fb4d0
Signed-off-by: Budimir Markovic <markovicbudimir@gmail.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://patch.msgid.link/20250807041811.678-1-markovicbudimir@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit 32950b1907919be86a7a2697d6f93d57068b3865)
Signed-off-by: Robert Kolchmeyer <rkolchmeyer@google.com>
(cherry picked from commit e283919390742c8510800e9c067f1418e885d72f)
Signed-off-by: Robert Kolchmeyer <rkolchmeyer@google.com>
Reviewed-on: https://cos-review.googlesource.com/c/third_party/kernel/+/109910
Reviewed-by: Kevin Berry <kpberry@google.com>
Tested-by: Cusky Presubmit Bot <presubmit@cos-infra-prod.iam.gserviceaccount.com>
diff --git a/net/vmw_vsock/af_vsock.c b/net/vmw_vsock/af_vsock.c
index f8f1a49..cdcffa0 100644
--- a/net/vmw_vsock/af_vsock.c
+++ b/net/vmw_vsock/af_vsock.c
@@ -654,7 +654,8 @@ static int __vsock_bind_connectible(struct vsock_sock *vsk,
unsigned int i;
for (i = 0; i < MAX_PORT_RETRIES; i++) {
- if (port <= LAST_RESERVED_PORT)
+ if (port == VMADDR_PORT_ANY ||
+ port <= LAST_RESERVED_PORT)
port = LAST_RESERVED_PORT + 1;
new_addr.svm_port = port++;
