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avformat/dhav: gracefully handle corrupted files

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Try to find next valid chunk in offsets of 0x8000 from last good one.
This commit is contained in:
Paul B Mahol 2019-08-24 10:59:49 +02:00 committed by Kieran Kunhya
parent 1cfba7fc75
commit 96fd07351a
1 changed files with 38 additions and 24 deletions
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60
libavformat/dhav.c
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@ -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)
;
@ -338,9 +351,8 @@ 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;
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;
}