demux, stream: add option to prevent opening referenced files

Quite irresponsibly hacked together. Sue me.

DOCS/man/options.rst

@@ -267,6 +267,26 @@ Playback Control
     Note that ``--playlist`` always loads all entries, so you use that instead
     if you really have the need for this functionality.
 
+``--access-references=<yes|no>``
+    Follow any references in the file being opened (default: yes). Disabling
+    this is helpful if the file is automatically scanned (e.g. thumbnail
+    generation). If the thumbnail scanner for example encounters a playlist
+    file, which contains network URLs, and the scanner should not open these,
+    enabling this option will prevent it. This option also disables ordered
+    chapters, mov reference files, opening of archives, and a number of other
+    features.
+
+    On older FFmpeg versions, this will not work in some cases. Some FFmpeg
+    demuxers might not respect this option.
+
+    This option does not prevent opening of paired subtitle files and such. Use
+    ``--autoload-files=no`` to prevent this.
+
+    This option does not always work if you open non-files (for example using
+    ``dvd://directory`` would open a whole bunch of files in the given
+    directory). Prefixing the filename with ``./`` if it doesn't start with
+    a ``/`` will avoid this.
+
 ``--loop-file=<N|inf|no>``
     Loop a single file N times. ``inf`` means forever, ``no`` means normal
     playback. For compatibility, ``--loop-file`` and ``--loop-file=yes`` are

demux/demux.c

@@ -89,6 +89,7 @@ struct demux_opts {
     double min_secs;
     int force_seekable;
     double min_secs_cache;
+    int access_references;
 };
 
 #define OPT_BASE_STRUCT struct demux_opts
@@ -100,6 +101,7 @@ const struct m_sub_options demux_conf = {
         OPT_INTRANGE("demuxer-max-bytes", max_bytes, 0, 0, INT_MAX),
         OPT_FLAG("force-seekable", force_seekable, 0),
         OPT_DOUBLE("cache-secs", min_secs_cache, M_OPT_MIN, .min = 0),
+        OPT_FLAG("access-references", access_references, 0),
         {0}
     },
     .size = sizeof(struct demux_opts),
@@ -108,6 +110,7 @@ const struct m_sub_options demux_conf = {
         .max_bytes = 400 * 1024 * 1024,
         .min_secs = 1.0,
         .min_secs_cache = 10.0,
+        .access_references = 1,
     },
 };
 
@@ -1213,6 +1216,7 @@ static struct demuxer *open_given_type(struct mpv_global *global,
         return NULL;
 
     struct demuxer *demuxer = talloc_ptrtype(NULL, demuxer);
+    struct demux_opts *opts = mp_get_config_group(demuxer, global, &demux_conf);
     *demuxer = (struct demuxer) {
         .desc = desc,
         .stream = stream,
@@ -1223,6 +1227,7 @@ static struct demuxer *open_given_type(struct mpv_global *global,
         .glog = log,
         .filename = talloc_strdup(demuxer, stream->url),
         .is_network = stream->is_network,
+        .access_references = opts->access_references,
         .events = DEMUX_EVENT_ALL,
     };
     demuxer->seekable = stream->seekable;
@@ -1230,8 +1235,6 @@ static struct demuxer *open_given_type(struct mpv_global *global,
         !demuxer->stream->uncached_stream->seekable)
         demuxer->seekable = false;
 
-    struct demux_opts *opts = mp_get_config_group(demuxer, global, &demux_conf);
-
     struct demux_internal *in = demuxer->in = talloc_ptrtype(demuxer, in);
     *in = (struct demux_internal){
         .log = demuxer->log,

demux/demux.h

@@ -186,6 +186,7 @@ typedef struct demuxer {
     // Typical examples: text subtitles, playlists
     bool fully_read;
     bool is_network; // opened directly from a network stream
+    bool access_references; // allow opening other files/URLs
 
     // Bitmask of DEMUX_EVENT_*
     int events;

demux/demux_cue.c

@@ -253,6 +253,9 @@ out:
 
 static int try_open_file(struct demuxer *demuxer, enum demux_check check)
 {
+    if (!demuxer->access_references)
+        return -1;
+
     struct stream *s = demuxer->stream;
     if (check >= DEMUX_CHECK_UNSAFE) {
         bstr d = stream_peek(s, PROBE_SIZE);

demux/demux_edl.c

@@ -295,6 +295,9 @@ static void build_mpv_edl_timeline(struct timeline *tl)
 
 static int try_open_file(struct demuxer *demuxer, enum demux_check check)
 {
+    if (!demuxer->access_references)
+        return -1;
+
     struct priv *p = talloc_zero(demuxer, struct priv);
     demuxer->priv = p;
     demuxer->fully_read = true;

demux/demux_lavf.c

@@ -22,6 +22,7 @@
 #include <stdbool.h>
 #include <string.h>
 #include <strings.h>
+#include <errno.h>
 #include <assert.h>
 
 #include "config.h"
@@ -754,6 +755,14 @@ static int interrupt_cb(void *ctx)
     return mp_cancel_test(priv->stream->cancel);
 }
 
+static int block_io_open(struct AVFormatContext *s, AVIOContext **pb,
+                         const char *url, int flags, AVDictionary **options)
+{
+    struct demuxer *demuxer = s->opaque;
+    MP_ERR(demuxer, "Not opening '%s' due to --access-references=no.\n", url);
+    return AVERROR(EACCES);
+}
+
 static int demux_open_lavf(demuxer_t *demuxer, enum demux_check check)
 {
     AVFormatContext *avfc;
@@ -855,6 +864,12 @@ static int demux_open_lavf(demuxer_t *demuxer, enum demux_check check)
         .opaque = demuxer,
     };
 
+#if HAVE_AVFORMAT_IOOPEN
+    avfc->opaque = demuxer;
+    if (!demuxer->access_references)
+        avfc->io_open = block_io_open;
+#endif
+
     mp_set_avdict(&dopts, lavfdopts->avopts);
 
     if (avformat_open_input(&avfc, priv->filename, priv->avif, &dopts) < 0) {

demux/demux_libarchive.c

@@ -32,6 +32,9 @@ static int cmp_filename(const void *a, const void *b)
 
 static int open_file(struct demuxer *demuxer, enum demux_check check)
 {
+    if (!demuxer->access_references)
+        return -1;
+
     int flags = 0;
     int probe_size = STREAM_BUFFER_SIZE;
     if (check <= DEMUX_CHECK_REQUEST) {

demux/demux_mkv_timeline.c

@@ -519,7 +519,7 @@ void build_ordered_chapter_timeline(struct timeline *tl)
         .opts = mp_get_config_group(ctx, tl->global, NULL),
     };
 
-    if (!ctx->opts->ordered_chapters) {
+    if (!ctx->opts->ordered_chapters || !demuxer->access_references) {
         MP_INFO(demuxer, "File uses ordered chapters, but "
                 "you have disabled support for them. Ignoring.\n");
         talloc_free(ctx);

demux/demux_playlist.c

@@ -283,6 +283,8 @@ static int parse_dir(struct pl_parser *p)
         return 0;
 
     char *path = mp_file_get_path(p, bstr0(p->real_stream->url));
+    if (!path)
+        return -1;
 
     char **files = NULL;
     int num_files = 0;
@@ -339,6 +341,9 @@ static const struct pl_format *probe_pl(struct pl_parser *p)
 
 static int open_file(struct demuxer *demuxer, enum demux_check check)
 {
+    if (!demuxer->access_references)
+        return -1;
+
     bool force = check < DEMUX_CHECK_UNSAFE || check == DEMUX_CHECK_REQUEST;
 
     struct pl_parser *p = talloc_zero(NULL, struct pl_parser);

demux/demux_rar.c

@@ -23,6 +23,9 @@
 
 static int open_file(struct demuxer *demuxer, enum demux_check check)
 {
+    if (!demuxer->access_references)
+        return -1;
+
     if (RarProbe(demuxer->stream))
         return -1;
 

stream/stream.c

@@ -230,6 +230,12 @@ static int open_internal(const stream_info_t *sinfo, const char *url, int flags,
     s->is_network = sinfo->is_network;
     s->mode = flags & (STREAM_READ | STREAM_WRITE);
 
+    if (global->config) {
+        int opt;
+        mp_read_option_raw(global, "access-references", &m_option_type_flag, &opt);
+        s->access_references = opt;
+    }
+
     MP_VERBOSE(s, "Opening %s\n", url);
 
     if ((s->mode & STREAM_WRITE) && !sinfo->can_write) {

stream/stream.h

@@ -197,6 +197,7 @@ typedef struct stream {
     bool fast_skip : 1; // consider stream fast enough to fw-seek by skipping
     bool is_network : 1; // original stream_info_t.is_network flag
     bool allow_caching : 1; // stream cache makes sense
+    bool access_references : 1; // open other streams
     struct mp_log *log;
     struct mpv_global *global;
 

stream/stream_bluray.c

@@ -569,6 +569,9 @@ static int bdmv_dir_stream_open(stream_t *stream)
         .cfg_title = BLURAY_DEFAULT_TITLE,
     };
 
+    if (!stream->access_references)
+        goto unsupported;
+
     char *path = mp_file_get_path(priv, bstr0(stream->url));
     if (!path)
         goto unsupported;

stream/stream_dvd.c

@@ -951,6 +951,9 @@ static int ifo_stream_open(stream_t *stream)
     dvd_priv_t *priv = talloc_zero(stream, dvd_priv_t);
     stream->priv = priv;
 
+    if (!stream->access_references)
+        goto unsupported;
+
     char *path = mp_file_get_path(priv, bstr0(stream->url));
     if (!path)
         goto unsupported;

stream/stream_dvdnav.c

@@ -562,6 +562,9 @@ static int ifo_dvdnav_stream_open(stream_t *stream)
     struct priv *priv = talloc_zero(stream, struct priv);
     stream->priv = priv;
 
+    if (!stream->access_references)
+        goto unsupported;
+
     priv->track = TITLE_LONGEST;
 
     char *path = mp_file_get_path(priv, bstr0(stream->url));

wscript

@@ -528,6 +528,12 @@ FFmpeg/Libav libraries. You need at least {0}. Aborting.".format(libav_versions_
         'func': check_statement('libavutil/frame.h',
                                 'AV_FRAME_DATA_MASTERING_DISPLAY_METADATA',
                                 use='libav'),
+    }, {
+        'name': 'avformat-ioopen',
+        'desc': 'libavformat io_open callback',
+        'func': check_statement('libavformat/avformat.h',
+                                'offsetof(AVFormatContext, io_open)',
+                                use='libav'),
     }
 ]