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avformat/matroskadec: Redo EOF handling

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This commit closes the last hole in the system of checks for a
known-length file ending too early: Now an error message is emitted
in case the file ends directly after an EBML element.

Furthermore, this commit adds a check and a corresponding warning
whether there is data beyond the Matroska segment (only reasonable for
known-length segments). If everything looks alright, then parsing is
stopped as soon as EOF is reached (in contrast, the earlier code would
always call matroska_resync at the end).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2019-05-17 00:30:11 +02:00 committed by James Almer
parent 38255cdcf8
commit 3ed2755baa
1 changed files with 18 additions and 5 deletions
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23
libavformat/matroskadec.c
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@ -1187,10 +1187,15 @@ static int ebml_parse(MatroskaDemuxContext *matroska,
if (matroska->is_live)
// in live mode, finish parsing if EOF is reached.
return 1;
if (level && level->length == EBML_UNKNOWN_LENGTH && pos == avio_tell(pb)) {
// Unknown-length levels automatically end at EOF.
matroska->num_levels--;
return LEVEL_ENDED;
if (level && pos == avio_tell(pb)) {
if (level->length == EBML_UNKNOWN_LENGTH) {
// Unknown-length levels automatically end at EOF.
matroska->num_levels--;
return LEVEL_ENDED;
} else {
av_log(matroska->ctx, AV_LOG_ERROR, "File ended prematurely "
"at pos. %"PRIu64" (0x%"PRIx64")\n", pos, pos);
}
}
}
return res;
@ -3622,6 +3627,14 @@ static int matroska_parse_cluster(MatroskaDemuxContext *matroska)
ebml_free(matroska_blockgroup, block);
memset(block, 0, sizeof(*block));
} else if (!matroska->num_levels) {
if (!avio_feof(matroska->ctx->pb)) {
avio_r8(matroska->ctx->pb);
if (!avio_feof(matroska->ctx->pb)) {
av_log(matroska->ctx, AV_LOG_WARNING, "File extends beyond "
"end of segment.\n");
return AVERROR_INVALIDDATA;
}
}
matroska->done = 1;
return AVERROR_EOF;
}
@ -3642,7 +3655,7 @@ static int matroska_read_packet(AVFormatContext *s, AVPacket *pkt)
while (matroska_deliver_packet(matroska, pkt)) {
if (matroska->done)
return (ret < 0) ? ret : AVERROR_EOF;
if (matroska_parse_cluster(matroska) < 0)
if (matroska_parse_cluster(matroska) < 0 && !matroska->done)
ret = matroska_resync(matroska, matroska->resync_pos);
}