How about this one, Michael? Rather than using the obviously dangerous
av_realloc() it uses av_malloc() to allocate new memory for the private
data, then copies the private data to it, frees the pointer to the
original private data, and finally sets track->codec->priv_data to the
newly allocated memory.
Mats
--
Mats Peterson
http://matsp888.no-ip.org/~mats/
>From a0aef3427e91adb46de2bc119f2367f4764d601a Mon Sep 17 00:00:00 2001
From: Mats Peterson <matsp...@yahoo.com>
Date: Sun, 10 Jan 2016 03:59:21 +0100
Subject: [PATCH v5] lavf/matroskadec: Normalize noncompliant A_QUICKTIME/V_QUICKTIME private data
This patch adds a new static function get_qt_codec() that takes care of
the initial retrieval of the fourcc and codec ID for A_QUICKTIME and
V_QUICKTIME. It also normalizes noncompliant private data found in some
older files that incorrectly starts with the fourcc by expanding/shifting
the data by 4 bytes, and storing the data size at the start. This is
necessary in order for the rest of the code in the A_QUICKTIME and
V_QUICKTIME blocks (and most likely other code as well) to correctly
parse the private data.
---
libavformat/matroskadec.c | 48 +++++++++++++++++++++++++++++++++------------
1 file changed, 35 insertions(+), 13 deletions(-)
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c
index be4e300..9e9e074 100644
--- a/libavformat/matroskadec.c
+++ b/libavformat/matroskadec.c
@@ -1708,6 +1708,33 @@ static void mkv_stereo_mode_display_mul(int stereo_mode, int *h_width, int *h_he
}
}
+static int get_qt_codec(MatroskaTrack *track, uint32_t *fourcc, enum AVCodecID *codec_id)
+{
+ const AVCodecTag *codec_tags;
+
+ codec_tags = track->type == MATROSKA_TRACK_TYPE_VIDEO ?
+ ff_codec_movvideo_tags : ff_codec_movaudio_tags;
+
+ /* Normalize noncompliant private data that starts with the fourcc
+ * by expanding/shifting the data by 4 bytes and storing the data
+ * size at the start. */
+ if (ff_codec_get_id(codec_tags, AV_RL32(track->codec_priv.data))) {
+ uint8_t *p = av_malloc(track->codec_priv.size + 4);
+ if (!p)
+ return AVERROR(ENOMEM);
+ memcpy(p + 4, track->codec_priv.data, track->codec_priv.size);
+ av_free(track->codec_priv.data);
+ track->codec_priv.data = p;
+ track->codec_priv.size += 4;
+ AV_WB32(track->codec_priv.data, track->codec_priv.size);
+ }
+
+ *fourcc = AV_RL32(track->codec_priv.data + 4);
+ *codec_id = ff_codec_get_id(codec_tags, *fourcc);
+
+ return 0;
+}
+
static int matroska_parse_tracks(AVFormatContext *s)
{
MatroskaDemuxContext *matroska = s->priv_data;
@@ -1861,14 +1888,12 @@ static int matroska_parse_tracks(AVFormatContext *s)
fourcc = st->codec->codec_tag;
extradata_offset = FFMIN(track->codec_priv.size, 18);
} else if (!strcmp(track->codec_id, "A_QUICKTIME")
- && (track->codec_priv.size >= 36)
+ /* Normally 36, but allow noncompliant private data */
+ && (track->codec_priv.size >= 32)
&& (track->codec_priv.data)) {
- fourcc = AV_RL32(track->codec_priv.data + 4);
- codec_id = ff_codec_get_id(ff_codec_movaudio_tags, fourcc);
- if (ff_codec_get_id(ff_codec_movaudio_tags, AV_RL32(track->codec_priv.data))) {
- fourcc = AV_RL32(track->codec_priv.data);
- codec_id = ff_codec_get_id(ff_codec_movaudio_tags, fourcc);
- }
+ int ret = get_qt_codec(track, &fourcc, &codec_id);
+ if (ret < 0)
+ return ret;
if (fourcc == 0) {
if (track->audio.bitdepth == 8) {
fourcc = MKTAG('r','a','w',' ');
@@ -1881,12 +1906,9 @@ static int matroska_parse_tracks(AVFormatContext *s)
} else if (!strcmp(track->codec_id, "V_QUICKTIME") &&
(track->codec_priv.size >= 21) &&
(track->codec_priv.data)) {
- fourcc = AV_RL32(track->codec_priv.data + 4);
- codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
- if (ff_codec_get_id(ff_codec_movvideo_tags, AV_RL32(track->codec_priv.data))) {
- fourcc = AV_RL32(track->codec_priv.data);
- codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
- }
+ int ret = get_qt_codec(track, &fourcc, &codec_id);
+ if (ret < 0)
+ return ret;
if (codec_id == AV_CODEC_ID_NONE && AV_RL32(track->codec_priv.data+4) == AV_RL32("SMI ")) {
fourcc = MKTAG('S','V','Q','3');
codec_id = ff_codec_get_id(ff_codec_movvideo_tags, fourcc);
--
1.7.10.4
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