[FFmpeg-cvslog] avformat/dhav: gracefully handle corrupted files
Paul B Mahol
git at videolan.org
Sat Aug 24 22:35:05 EEST 2019
ffmpeg | branch: master | Paul B Mahol <onemda at gmail.com> | Sat Aug 24 10:59:49 2019 +0200| [96fd07351a8dabcae52ee4a207ee831f4c54ba51] | committer: Kieran Kunhya
avformat/dhav: gracefully handle corrupted files
Try to find next valid chunk in offsets of 0x8000 from last good one.
> http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=96fd07351a8dabcae52ee4a207ee831f4c54ba51
---
libavformat/dhav.c | 62 +++++++++++++++++++++++++++++++++---------------------
1 file changed, 38 insertions(+), 24 deletions(-)
diff --git a/libavformat/dhav.c b/libavformat/dhav.c
index e6f61eeb66..c80246c4e9 100644
--- a/libavformat/dhav.c
+++ b/libavformat/dhav.c
@@ -39,6 +39,7 @@ typedef struct DHAVContext {
int audio_channels;
int audio_codec;
int sample_rate;
+ int64_t last_good_pos;
int video_stream_index;
int audio_stream_index;
@@ -80,6 +81,7 @@ static int dhav_read_header(AVFormatContext *s)
s->ctx_flags |= AVFMTCTX_NOHEADER;
dhav->video_stream_index = -1;
dhav->audio_stream_index = -1;
+ dhav->last_good_pos = avio_tell(s->pb);
return 0;
}
@@ -129,26 +131,26 @@ static const uint32_t sample_rates[] = {
static int parse_ext(AVFormatContext *s, int length)
{
DHAVContext *dhav = s->priv_data;
- int index;
+ int index, ret;
while (length > 0) {
int type = avio_r8(s->pb);
switch (type) {
case 0x80:
- avio_skip(s->pb, 1);
+ ret = avio_skip(s->pb, 1);
dhav->width = 8 * avio_r8(s->pb);
dhav->height = 8 * avio_r8(s->pb);
length -= 4;
break;
case 0x81:
- avio_skip(s->pb, 1);
+ ret = avio_skip(s->pb, 1);
dhav->video_codec = avio_r8(s->pb);
dhav->frame_rate = avio_r8(s->pb);
length -= 4;
break;
case 0x82:
- avio_skip(s->pb, 3);
+ ret = avio_skip(s->pb, 3);
dhav->width = avio_rl16(s->pb);
dhav->height = avio_rl16(s->pb);
length -= 8;
@@ -165,11 +167,11 @@ static int parse_ext(AVFormatContext *s, int length)
length -= 4;
break;
case 0x88:
- avio_skip(s->pb, 7);
+ ret = avio_skip(s->pb, 7);
length -= 8;
break;
case 0x8c:
- avio_skip(s->pb, 1);
+ ret = avio_skip(s->pb, 1);
dhav->audio_channels = avio_r8(s->pb);
dhav->audio_codec = avio_r8(s->pb);
index = avio_r8(s->pb);
@@ -178,7 +180,7 @@ static int parse_ext(AVFormatContext *s, int length)
} else {
dhav->sample_rate = 8000;
}
- avio_skip(s->pb, 3);
+ ret = avio_skip(s->pb, 3);
length -= 8;
break;
case 0x91:
@@ -188,7 +190,7 @@ static int parse_ext(AVFormatContext *s, int length)
case 0x9a:
case 0x9b: // sample aspect ratio
case 0xb3:
- avio_skip(s->pb, 7);
+ ret = avio_skip(s->pb, 7);
length -= 8;
break;
case 0x84:
@@ -199,14 +201,17 @@ static int parse_ext(AVFormatContext *s, int length)
case 0xa0:
case 0xb2:
case 0xb4:
- avio_skip(s->pb, 3);
+ ret = avio_skip(s->pb, 3);
length -= 4;
break;
default:
av_log(s, AV_LOG_INFO, "Unknown type: %X, skipping rest of header.\n", type);
- avio_skip(s->pb, length - 1);
+ ret = avio_skip(s->pb, length - 1);
length = 0;
}
+
+ if (ret < 0)
+ return ret;
}
return 0;
@@ -215,18 +220,29 @@ static int parse_ext(AVFormatContext *s, int length)
static int read_chunk(AVFormatContext *s)
{
DHAVContext *dhav = s->priv_data;
- unsigned frame_length, ext_length;
+ int frame_length, ext_length;
int64_t start, end;
int ret;
- start = avio_tell(s->pb);
-
if (avio_feof(s->pb))
return AVERROR_EOF;
- if (avio_rl32(s->pb) != MKTAG('D','H','A','V'))
- return AVERROR_INVALIDDATA;
+ if (avio_rl32(s->pb) != MKTAG('D','H','A','V')) {
+ dhav->last_good_pos += 0x8000;
+ avio_seek(s->pb, dhav->last_good_pos, SEEK_SET);
+
+ while (avio_rl32(s->pb) != MKTAG('D','H','A','V')) {
+ if (avio_feof(s->pb))
+ return AVERROR_EOF;
+ dhav->last_good_pos += 0x8000;
+ ret = avio_skip(s->pb, 0x8000 - 4);
+ if (ret < 0)
+ return ret;
+ }
+ }
+ start = avio_tell(s->pb) - 4;
+ dhav->last_good_pos = start;
dhav->type = avio_r8(s->pb);
dhav->subtype = avio_r8(s->pb);
dhav->channel = avio_r8(s->pb);
@@ -237,8 +253,8 @@ static int read_chunk(AVFormatContext *s)
if (frame_length < 24)
return AVERROR_INVALIDDATA;
if (dhav->type == 0xf1) {
- avio_skip(s->pb, frame_length - 16);
- return 0;
+ ret = avio_skip(s->pb, frame_length - 16);
+ return ret < 0 ? ret : 0;
}
dhav->date = avio_rl32(s->pb);
@@ -258,11 +274,8 @@ static int read_chunk(AVFormatContext *s)
static int dhav_read_packet(AVFormatContext *s, AVPacket *pkt)
{
DHAVContext *dhav = s->priv_data;
- int64_t start;
int ret;
- start = avio_tell(s->pb);
-
while ((ret = read_chunk(s)) == 0)
;
@@ -338,10 +351,9 @@ static int dhav_read_packet(AVFormatContext *s, AVPacket *pkt)
if (pkt->stream_index >= 0)
pkt->pts = get_pts(s, s->streams[pkt->stream_index]->priv_data);
pkt->duration = 1;
- pkt->pos = start;
- if (avio_rl32(s->pb) != MKTAG('d','h','a','v'))
- return AVERROR_INVALIDDATA;
- avio_skip(s->pb, 4);
+ pkt->pos = dhav->last_good_pos;
+ if (avio_rl32(s->pb) == MKTAG('d','h','a','v'))
+ avio_skip(s->pb, 4);
return ret;
}
@@ -349,6 +361,7 @@ static int dhav_read_packet(AVFormatContext *s, AVPacket *pkt)
static int dhav_read_seek(AVFormatContext *s, int stream_index,
int64_t timestamp, int flags)
{
+ DHAVContext *dhav = s->priv_data;
AVStream *st = s->streams[stream_index];
int index = av_index_search_timestamp(st, timestamp, flags);
int64_t pts;
@@ -367,6 +380,7 @@ static int dhav_read_seek(AVFormatContext *s, int stream_index,
dst->pts = pts;
dst->last_timestamp = AV_NOPTS_VALUE;
}
+ dhav->last_good_pos = avio_tell(s->pb);
return 0;
}
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