typefinders: skip ffmpeg typefinders if there isn't enough data

ffmpeg typefinders don't do bounds checking for small chunks of
data, so just skip them if we don't have a lot of data, to avoid
invalid memory access and/or crashes.
This commit is contained in:
Tim-Philipp Müller 2009-08-21 02:58:58 +01:00
parent 30da9c07da
commit 0044128487

View file

@ -1252,6 +1252,8 @@ no_info:
}
#define GST_FFMPEG_TYPE_FIND_SIZE 4096
#define GST_FFMPEG_TYPE_FIND_MIN_SIZE 256
static void
gst_ffmpegdemux_type_find (GstTypeFind * tf, gpointer priv)
{
@ -1267,6 +1269,16 @@ gst_ffmpegdemux_type_find (GstTypeFind * tf, gpointer priv)
if (length == 0 || length > GST_FFMPEG_TYPE_FIND_SIZE)
length = GST_FFMPEG_TYPE_FIND_SIZE;
/* The ffmpeg typefinders assume there's a certain minimum amount of data
* and will happily do invalid memory access if there isn't, so let's just
* skip the ffmpeg typefinders if the data available is too short
* (in which case it's unlikely to be a media file anyway) */
if (length < GST_FFMPEG_TYPE_FIND_MIN_SIZE) {
GST_LOG ("not typefinding %" G_GUINT64_FORMAT " bytes, too short", length);
return;
}
GST_LOG ("typefinding %" G_GUINT64_FORMAT " bytes", length);
if (in_plugin->read_probe &&
(data = gst_type_find_peek (tf, 0, length)) != NULL) {
AVProbeData probe_data;