net: Reject non-netdevs in qmp_netdev_del()

The netdev_del command crashes when given a -net device, because it
calls qemu_opts_del(NULL).

Check that this is a -netdev before attempting to delete it and the
QemuOpts.

Note the subtle change from qemu_find_opts_err("netdev", errp) to
qemu_find_opts_err("netdev", NULL).  Since "netdev" is a built in
options group and we don't check for NULL return anyway, there's no use
in passing errp here.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 8 insertions, 1 deletions

diff --git a/net.c b/net.c
index ae4bc0d..e8ae13e 100644
--- a/net.c
+++ b/net.c
@@ -827,6 +827,7 @@ exit_err:
 void qmp_netdev_del(const char *id, Error **errp)
 {
     NetClientState *nc;
+    QemuOpts *opts;
 
     nc = qemu_find_netdev(id);
     if (!nc) {
@@ -834,8 +835,14 @@ void qmp_netdev_del(const char *id, Error **errp)
         return;
     }
 
+    opts = qemu_opts_find(qemu_find_opts_err("netdev", NULL), id);
+    if (!opts) {
+        error_setg(errp, "Device '%s' is not a netdev", id);
+        return;
+    }
+
     qemu_del_net_client(nc);
-    qemu_opts_del(qemu_opts_find(qemu_find_opts_err("netdev", errp), id));
+    qemu_opts_del(opts);
 }
 
 void print_net_client(Monitor *mon, NetClientState *nc)