5.4-stable review patch. If anyone has any objections, please let me know.
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From: Budimir Markovic markovicbudimir@gmail.com
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.
Fixes: d021c344051a ("VSOCK: Introduce VM Sockets") Reported-by: Budimir Markovic markovicbudimir@gmail.com 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 --- net/vmw_vsock/af_vsock.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
--- a/net/vmw_vsock/af_vsock.c +++ b/net/vmw_vsock/af_vsock.c @@ -487,7 +487,8 @@ static int __vsock_bind_stream(struct vs 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++;