scsi: iscsi_tcp: restrict to TCP sockets

Nothing prevents iscsi_sw_tcp_conn_bind() to receive file descriptor
pointing to non TCP socket (af_unix for example).

Return -EINVAL if this is attempted, instead of crashing the kernel.

Fixes: 7ba2471 ("[SCSI] open-iscsi/linux-iscsi-5 Initiator: Initiator code")
Signed-off-by: Eric Dumazet <[email protected]>
Cc: Lee Duncan <[email protected]>
Cc: Chris Leech <[email protected]>
Cc: Mike Christie <[email protected]>
Cc: "James E.J. Bottomley" <[email protected]>
Cc: "Martin K. Petersen" <[email protected]>
Cc: [email protected]
Cc: [email protected]
Reviewed-by: Mike Christie <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: edumazet

drivers/scsi/iscsi_tcp.c

@@ -724,6 +724,10 @@ iscsi_sw_tcp_conn_bind(struct iscsi_cls_session *cls_session,
 		return -EEXIST;
 	}
 
+	err = -EINVAL;
+	if (!sk_is_tcp(sock->sk))
+		goto free_socket;
+
 	err = iscsi_conn_bind(cls_session, cls_conn, is_leading);
 	if (err)
 		goto free_socket;