avformat/hls: forbid all protocols except http(s) & file

Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavformat/hls.c

@@ -610,6 +610,10 @@ static int open_url(HLSContext *c, URLContext **uc, const char *url, AVDictionar
 {
     AVDictionary *tmp = NULL;
     int ret;
+    const char *proto_name = avio_find_protocol_name(url);
+    // only http(s) & file are allowed
+    if (!av_strstart(proto_name, "http", NULL) && !av_strstart(proto_name, "file", NULL))
+        return AVERROR_INVALIDDATA;
 
     av_dict_copy(&tmp, c->avio_opts, 0);
     av_dict_copy(&tmp, opts, 0);