net: Fix a potential segfault
If user forgets to provide any backend types for '-netdev' in qemu CLI,
It triggers seg fault.
e.g.
Expected:
$ qemu -netdev id=net0
qemu-system-x86_64: Parameter 'type' is missing
Actual:
$ qemu -netdev id=net0
Segmentation fault (core dumped)
Fixes: 547203ead4327 ("net: List available netdevs with "-netdev help")
Reviewed-by: Thomas Huth <thuth@redhat.com>
Cc: qemu-stable@nongnu.org
Signed-off-by: Lin Ma <lma@suse.com>
Signed-off-by: Jason Wang <jasowang@redhat.com>
diff --git a/net/net.c b/net/net.c
index efb9eaf..2a31339 100644
--- a/net/net.c
+++ b/net/net.c
@@ -1093,7 +1093,9 @@
int ret = -1;
Visitor *v = opts_visitor_new(opts);
- if (is_netdev && is_help_option(qemu_opt_get(opts, "type"))) {
+ const char *type = qemu_opt_get(opts, "type");
+
+ if (is_netdev && type && is_help_option(type)) {
show_netdevs();
exit(0);
} else {
