demux_cue: remove cue tracks which have a null filename.

This can happen if the file references a track, but does not specify
an INDEX 01 for it. This would cause mpv to just segfault due to
dereferencing the null pointer as a string.

A file causing this was observed in the wild by
ExactAudioCopy v0.99pb4 for a disk that contained a data track at the
end.

1 files changed, 12 insertions, 2 deletions

diff --git a/demux/demux_cue.c b/demux/demux_cue.c
index 43420573ec..da84fc60c1 100644
--- a/demux/demux_cue.c
+++ b/demux/demux_cue.c
@@ -150,8 +150,18 @@ static void build_timeline(struct timeline *tl)
 
     add_source(tl, tl->demuxer);
 
-    struct cue_track *tracks = p->f->tracks;
-    size_t track_count = p->f->num_tracks;
+    struct cue_track *tracks = NULL;
+    size_t track_count = 0;
+
+    for (size_t n = 0; n < p->f->num_tracks; n++) {
+        struct cue_track *track = &p->f->tracks[n];
+        if (track->filename) {
+            MP_TARRAY_APPEND(ctx, tracks, track_count, *track);
+        } else {
+            MP_WARN(tl->demuxer, "No file specified for track entry %zd. "
+                    "It will be removed\n", n + 1);
+        }
+    }
 
     if (track_count == 0) {
         MP_ERR(tl, "CUE: no tracks found!\n");