ffmpeg | branch: release/4.4 | Michael Niedermayer <mich...@niedermayer.cc> | Thu Jun 24 19:53:47 2021 +0200| [bac4bb747a233f23b3183594207328f4a067e1fb] | committer: Michael Niedermayer
avformat/matroskadec: Reset state also on failure in matroska_reset_status() The calling code does not handle failures and will fail with assertion failures later. Seeking can always fail even when the position was previously read. Fixes: Assertion failure Fixes: 35253/clusterfuzz-testcase-minimized-ffmpeg_dem_MATROSKA_fuzzer-4693059982983168 Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/projects/ffmpeg Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> (cherry picked from commit d115eec97929e23fd1b06df2d95f48cf5000eb87) Signed-off-by: Michael Niedermayer <mich...@niedermayer.cc> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=bac4bb747a233f23b3183594207328f4a067e1fb --- libavformat/matroskadec.c | 19 ++++++++++++------- 1 file changed, 12 insertions(+), 7 deletions(-) diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index a2efdb42b0..fb1849f9c3 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -802,20 +802,22 @@ static int matroska_read_close(AVFormatContext *s); static int matroska_reset_status(MatroskaDemuxContext *matroska, uint32_t id, int64_t position) { + int64_t err = 0; if (position >= 0) { - int64_t err = avio_seek(matroska->ctx->pb, position, SEEK_SET); - if (err < 0) - return err; - } + err = avio_seek(matroska->ctx->pb, position, SEEK_SET); + if (err > 0) + err = 0; + } else + position = avio_tell(matroska->ctx->pb); matroska->current_id = id; matroska->num_levels = 1; matroska->unknown_count = 0; - matroska->resync_pos = avio_tell(matroska->ctx->pb); + matroska->resync_pos = position; if (id) matroska->resync_pos -= (av_log2(id) + 7) / 8; - return 0; + return err; } static int matroska_resync(MatroskaDemuxContext *matroska, int64_t last_pos) @@ -1871,6 +1873,7 @@ static int matroska_parse_seekhead_entry(MatroskaDemuxContext *matroska, uint32_t saved_id = matroska->current_id; int64_t before_pos = avio_tell(matroska->ctx->pb); int ret = 0; + int ret2; /* seek */ if (avio_seek(matroska->ctx->pb, pos, SEEK_SET) == pos) { @@ -1895,7 +1898,9 @@ static int matroska_parse_seekhead_entry(MatroskaDemuxContext *matroska, } /* Seek back - notice that in all instances where this is used * it is safe to set the level to 1. */ - matroska_reset_status(matroska, saved_id, before_pos); + ret2 = matroska_reset_status(matroska, saved_id, before_pos); + if (ret >= 0) + ret = ret2; return ret; } _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
