hw/net/can: Fix segfaults when using the devices without bus

The CAN devices can currently be used to crash QEMU, e.g.:

$ x86_64-softmmu/qemu-system-x86_64 -device kvaser_pci
Segmentation fault (core dumped)

So we've got to add a proper check here that the corresponding
bus is available.

Signed-off-by: Thomas Huth <[email protected]>
Message-Id: <1521193892[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

diff --git a/hw/net/can/can_sja1000.c b/hw/net/can/can_sja1000.c
index 629323312cfa2758737fa8cc1fdc771177ff26af..9a85038c8ad0095472bc6db39554d4bce53cd593 100644 (file)
--- a/hw/net/can/can_sja1000.c
+++ b/hw/net/can/can_sja1000.c
@@ -866,6 +866,10 @@ int can_sja_connect_to_bus(CanSJA1000State *s, CanBusState *bus)
 {
     s->bus_client.info = &can_sja_bus_client_info;
 
+    if (!bus) {
+        return -EINVAL;
+    }
+
     if (can_bus_insert_client(bus, &s->bus_client) < 0) {
         return -1;
     }