[YoutubeDL] Protect from infinite recursion due to recursively nested playlists (closes #27833)

1 files changed, 129 insertions, 107 deletions

diff --git a/youtube_dl/YoutubeDL.py b/youtube_dl/YoutubeDL.py
index 0ed4bc6ba..efd42fa63 100755
--- a/youtube_dl/YoutubeDL.py
+++ b/youtube_dl/YoutubeDL.py
@@ -338,6 +338,8 @@ class YoutubeDL(object):
     _pps = []
     _download_retcode = None
     _num_downloads = None
+    _playlist_level = 0
+    _playlist_urls = set()
     _screen_file = None
 
     def __init__(self, params=None, auto_init=True):
@@ -906,115 +908,23 @@ class YoutubeDL(object):
             return self.process_ie_result(
                 new_result, download=download, extra_info=extra_info)
         elif result_type in ('playlist', 'multi_video'):
-            # We process each entry in the playlist
-            playlist = ie_result.get('title') or ie_result.get('id')
-            self.to_screen('[download] Downloading playlist: %s' % playlist)
-
-            playlist_results = []
-
-            playliststart = self.params.get('playliststart', 1) - 1
-            playlistend = self.params.get('playlistend')
-            # For backwards compatibility, interpret -1 as whole list
-            if playlistend == -1:
-                playlistend = None
-
-            playlistitems_str = self.params.get('playlist_items')
-            playlistitems = None
-            if playlistitems_str is not None:
-                def iter_playlistitems(format):
-                    for string_segment in format.split(','):
-                        if '-' in string_segment:
-                            start, end = string_segment.split('-')
-                            for item in range(int(start), int(end) + 1):
-                                yield int(item)
-                        else:
-                            yield int(string_segment)
-                playlistitems = orderedSet(iter_playlistitems(playlistitems_str))
-
-            ie_entries = ie_result['entries']
-
-            def make_playlistitems_entries(list_ie_entries):
-                num_entries = len(list_ie_entries)
-                return [
-                    list_ie_entries[i - 1] for i in playlistitems
-                    if -num_entries <= i - 1 < num_entries]
-
-            def report_download(num_entries):
+            # Protect from infinite recursion due to recursively nested playlists
+            # (see https://github.com/ytdl-org/youtube-dl/issues/27833)
+            webpage_url = ie_result['webpage_url']
+            if webpage_url in self._playlist_urls:
                 self.to_screen(
-                    '[%s] playlist %s: Downloading %d videos' %
-                    (ie_result['extractor'], playlist, num_entries))
-
-            if isinstance(ie_entries, list):
-                n_all_entries = len(ie_entries)
-                if playlistitems:
-                    entries = make_playlistitems_entries(ie_entries)
-                else:
-                    entries = ie_entries[playliststart:playlistend]
-                n_entries = len(entries)
-                self.to_screen(
-                    '[%s] playlist %s: Collected %d video ids (downloading %d of them)' %
-                    (ie_result['extractor'], playlist, n_all_entries, n_entries))
-            elif isinstance(ie_entries, PagedList):
-                if playlistitems:
-                    entries = []
-                    for item in playlistitems:
-                        entries.extend(ie_entries.getslice(
-                            item - 1, item
-                        ))
-                else:
-                    entries = ie_entries.getslice(
-                        playliststart, playlistend)
-                n_entries = len(entries)
-                report_download(n_entries)
-            else:  # iterable
-                if playlistitems:
-                    entries = make_playlistitems_entries(list(itertools.islice(
-                        ie_entries, 0, max(playlistitems))))
-                else:
-                    entries = list(itertools.islice(
-                        ie_entries, playliststart, playlistend))
-                n_entries = len(entries)
-                report_download(n_entries)
-
-            if self.params.get('playlistreverse', False):
-                entries = entries[::-1]
-
-            if self.params.get('playlistrandom', False):
-                random.shuffle(entries)
-
-            x_forwarded_for = ie_result.get('__x_forwarded_for_ip')
-
-            for i, entry in enumerate(entries, 1):
-                self.to_screen('[download] Downloading video %s of %s' % (i, n_entries))
-                # This __x_forwarded_for_ip thing is a bit ugly but requires
-                # minimal changes
-                if x_forwarded_for:
-                    entry['__x_forwarded_for_ip'] = x_forwarded_for
-                extra = {
-                    'n_entries': n_entries,
-                    'playlist': playlist,
-                    'playlist_id': ie_result.get('id'),
-                    'playlist_title': ie_result.get('title'),
-                    'playlist_uploader': ie_result.get('uploader'),
-                    'playlist_uploader_id': ie_result.get('uploader_id'),
-                    'playlist_index': playlistitems[i - 1] if playlistitems else i + playliststart,
-                    'extractor': ie_result['extractor'],
-                    'webpage_url': ie_result['webpage_url'],
-                    'webpage_url_basename': url_basename(ie_result['webpage_url']),
-                    'extractor_key': ie_result['extractor_key'],
-                }
-
-                reason = self._match_entry(entry, incomplete=True)
-                if reason is not None:
-                    self.to_screen('[download] ' + reason)
-                    continue
+                    '[download] Skipping already downloaded playlist: %s'
+                    % ie_result.get('title') or ie_result.get('id'))
+                return
 
-                entry_result = self.__process_iterable_entry(entry, download, extra)
-                # TODO: skip failed (empty) entries?
-                playlist_results.append(entry_result)
-            ie_result['entries'] = playlist_results
-            self.to_screen('[download] Finished downloading playlist: %s' % playlist)
-            return ie_result
+            self._playlist_level += 1
+            self._playlist_urls.add(webpage_url)
+            try:
+                return self.__process_playlist(ie_result, download)
+            finally:
+                self._playlist_level -= 1
+                if not self._playlist_level:
+                    self._playlist_urls.clear()
         elif result_type == 'compat_list':
             self.report_warning(
                 'Extractor %s returned a compat_list result. '
@@ -1039,6 +949,118 @@ class YoutubeDL(object):
         else:
             raise Exception('Invalid result type: %s' % result_type)
 
+    def __process_playlist(self, ie_result, download):
+        # We process each entry in the playlist
+        playlist = ie_result.get('title') or ie_result.get('id')
+
+        self.to_screen('[download] Downloading playlist: %s' % playlist)
+
+        playlist_results = []
+
+        playliststart = self.params.get('playliststart', 1) - 1
+        playlistend = self.params.get('playlistend')
+        # For backwards compatibility, interpret -1 as whole list
+        if playlistend == -1:
+            playlistend = None
+
+        playlistitems_str = self.params.get('playlist_items')
+        playlistitems = None
+        if playlistitems_str is not None:
+            def iter_playlistitems(format):
+                for string_segment in format.split(','):
+                    if '-' in string_segment:
+                        start, end = string_segment.split('-')
+                        for item in range(int(start), int(end) + 1):
+                            yield int(item)
+                    else:
+                        yield int(string_segment)
+            playlistitems = orderedSet(iter_playlistitems(playlistitems_str))
+
+        ie_entries = ie_result['entries']
+
+        def make_playlistitems_entries(list_ie_entries):
+            num_entries = len(list_ie_entries)
+            return [
+                list_ie_entries[i - 1] for i in playlistitems
+                if -num_entries <= i - 1 < num_entries]
+
+        def report_download(num_entries):
+            self.to_screen(
+                '[%s] playlist %s: Downloading %d videos' %
+                (ie_result['extractor'], playlist, num_entries))
+
+        if isinstance(ie_entries, list):
+            n_all_entries = len(ie_entries)
+            if playlistitems:
+                entries = make_playlistitems_entries(ie_entries)
+            else:
+                entries = ie_entries[playliststart:playlistend]
+            n_entries = len(entries)
+            self.to_screen(
+                '[%s] playlist %s: Collected %d video ids (downloading %d of them)' %
+                (ie_result['extractor'], playlist, n_all_entries, n_entries))
+        elif isinstance(ie_entries, PagedList):
+            if playlistitems:
+                entries = []
+                for item in playlistitems:
+                    entries.extend(ie_entries.getslice(
+                        item - 1, item
+                    ))
+            else:
+                entries = ie_entries.getslice(
+                    playliststart, playlistend)
+            n_entries = len(entries)
+            report_download(n_entries)
+        else:  # iterable
+            if playlistitems:
+                entries = make_playlistitems_entries(list(itertools.islice(
+                    ie_entries, 0, max(playlistitems))))
+            else:
+                entries = list(itertools.islice(
+                    ie_entries, playliststart, playlistend))
+            n_entries = len(entries)
+            report_download(n_entries)
+
+        if self.params.get('playlistreverse', False):
+            entries = entries[::-1]
+
+        if self.params.get('playlistrandom', False):
+            random.shuffle(entries)
+
+        x_forwarded_for = ie_result.get('__x_forwarded_for_ip')
+
+        for i, entry in enumerate(entries, 1):
+            self.to_screen('[download] Downloading video %s of %s' % (i, n_entries))
+            # This __x_forwarded_for_ip thing is a bit ugly but requires
+            # minimal changes
+            if x_forwarded_for:
+                entry['__x_forwarded_for_ip'] = x_forwarded_for
+            extra = {
+                'n_entries': n_entries,
+                'playlist': playlist,
+                'playlist_id': ie_result.get('id'),
+                'playlist_title': ie_result.get('title'),
+                'playlist_uploader': ie_result.get('uploader'),
+                'playlist_uploader_id': ie_result.get('uploader_id'),
+                'playlist_index': playlistitems[i - 1] if playlistitems else i + playliststart,
+                'extractor': ie_result['extractor'],
+                'webpage_url': ie_result['webpage_url'],
+                'webpage_url_basename': url_basename(ie_result['webpage_url']),
+                'extractor_key': ie_result['extractor_key'],
+            }
+
+            reason = self._match_entry(entry, incomplete=True)
+            if reason is not None:
+                self.to_screen('[download] ' + reason)
+                continue
+
+            entry_result = self.__process_iterable_entry(entry, download, extra)
+            # TODO: skip failed (empty) entries?
+            playlist_results.append(entry_result)
+        ie_result['entries'] = playlist_results
+        self.to_screen('[download] Finished downloading playlist: %s' % playlist)
+        return ie_result
+
     @__handle_extraction_exceptions
     def __process_iterable_entry(self, entry, download, extra_info):
         return self.process_ie_result(