media: vidtv: mux: Add check and kfree for kstrdup

Add check for the return value of kstrdup() and return the error
if it fails in order to avoid NULL pointer dereference.
Moreover, use kfree() in the later error handling in order to avoid
memory leak.

Fixes: c2f78f0c ("media: vidtv: psi: add a Network Information Table (NIT)")
Signed-off-by: Jiasheng Jiang <jiasheng@iscas.ac.cn>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/test-drivers/vidtv/vidtv_mux.c

@@ -504,13 +504,16 @@ struct vidtv_mux *vidtv_mux_init(struct dvb_frontend *fe,
 	m->priv = args->priv;
 	m->network_id = args->network_id;
 	m->network_name = kstrdup(args->network_name, GFP_KERNEL);
+	if (!m->network_name)
+		goto free_mux_buf;
+
 	m->timing.current_jiffies = get_jiffies_64();
 
 	if (args->channels)
 		m->channels = args->channels;
 	else
 		if (vidtv_channels_init(m) < 0)
-			goto free_mux_buf;
+			goto free_mux_network_name;
 
 	/* will alloc data for pmt_sections after initializing pat */
 	if (vidtv_channel_si_init(m) < 0)
@@ -527,6 +530,8 @@ struct vidtv_mux *vidtv_mux_init(struct dvb_frontend *fe,
 	vidtv_channel_si_destroy(m);
 free_channels:
 	vidtv_channels_destroy(m);
+free_mux_network_name:
+	kfree(m->network_name);
 free_mux_buf:
 	vfree(m->mux_buf);
 free_mux: