net: vmw_vsock: vmci: Check memcpy_from_msg()

Bugzilla: https://bugzilla.redhat.com/2160028

commit 44aa5a6
Author: Artem Chernyshev <artem.chernyshev@red-soft.ru>
Date:   Tue Dec 6 09:58:34 2022 +0300

    net: vmw_vsock: vmci: Check memcpy_from_msg()

    vmci_transport_dgram_enqueue() does not check the return value
    of memcpy_from_msg().  If memcpy_from_msg() fails, it is possible that
    uninitialized memory contents are sent unintentionally instead of user's
    message in the datagram to the destination.  Return with an error if
    memcpy_from_msg() fails.

    Found by Linux Verification Center (linuxtesting.org) with SVACE.

    Fixes: 0f7db23 ("vmci_transport: switch ->enqeue_dgram, ->enqueue_stream and ->dequeue_stream to msghdr")
    Signed-off-by: Artem Chernyshev <artem.chernyshev@red-soft.ru>
    Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
    Reviewed-by: Vishnu Dasa <vdasa@vmware.com>
    Signed-off-by: David S. Miller <davem@davemloft.net>

Signed-off-by: Stefano Garzarella <sgarzare@redhat.com>

Author: stefano-garzarella

net/vmw_vsock/vmci_transport.c

@@ -1711,7 +1711,11 @@ static int vmci_transport_dgram_enqueue(
 	if (!dg)
 		return -ENOMEM;
 
-	memcpy_from_msg(VMCI_DG_PAYLOAD(dg), msg, len);
+	err = memcpy_from_msg(VMCI_DG_PAYLOAD(dg), msg, len);
+	if (err) {
+		kfree(dg);
+		return err;
+	}
 
 	dg->dst = vmci_make_handle(remote_addr->svm_cid,
 				   remote_addr->svm_port);