diff options
| -rw-r--r-- | libavformat/matroskadec.c | 74 |
1 files changed, 46 insertions, 28 deletions
diff --git a/libavformat/matroskadec.c b/libavformat/matroskadec.c index 0e9938b65e..59388efb64 100644 --- a/libavformat/matroskadec.c +++ b/libavformat/matroskadec.c @@ -796,33 +796,32 @@ static int ebml_level_end(MatroskaDemuxContext *matroska) * Returns: number of bytes read, < 0 on error */ static int ebml_read_num(MatroskaDemuxContext *matroska, AVIOContext *pb, - int max_size, uint64_t *number) + int max_size, uint64_t *number, int eof_forbidden) { - int read = 1, n = 1; - uint64_t total = 0; + int read, n = 1; + uint64_t total; + int64_t pos; - /* The first byte tells us the length in bytes - avio_r8() can normally - * return 0, but since that's not a valid first ebmlID byte, we can - * use it safely here to catch EOS. */ - if (!(total = avio_r8(pb))) { - /* we might encounter EOS here */ - if (!avio_feof(pb)) { - int64_t pos = avio_tell(pb); - av_log(matroska->ctx, AV_LOG_ERROR, - "Read error at pos. %"PRIu64" (0x%"PRIx64")\n", - pos, pos); - return pb->error ? pb->error : AVERROR(EIO); - } - return AVERROR_EOF; - } + /* The first byte tells us the length in bytes - except when it is zero. */ + total = avio_r8(pb); + if (pb->eof_reached) + goto err; /* get the length of the EBML number */ read = 8 - ff_log2_tab[total]; - if (read > max_size) { - int64_t pos = avio_tell(pb) - 1; - av_log(matroska->ctx, AV_LOG_ERROR, - "Invalid EBML number size tag 0x%02x at pos %"PRIu64" (0x%"PRIx64")\n", - (uint8_t) total, pos, pos); + + if (!total || read > max_size) { + pos = avio_tell(pb) - 1; + if (!total) { + av_log(matroska->ctx, AV_LOG_ERROR, + "0x00 at pos %"PRId64" (0x%"PRIx64") invalid as first byte " + "of an EBML number\n", pos, pos); + } else { + av_log(matroska->ctx, AV_LOG_ERROR, + "Length %d indicated by an EBML number's first byte 0x%02x " + "at pos %"PRId64" (0x%"PRIx64") exceeds max length %d.\n", + read, (uint8_t) total, pos, pos, max_size); + } return AVERROR_INVALIDDATA; } @@ -831,9 +830,29 @@ static int ebml_read_num(MatroskaDemuxContext *matroska, AVIOContext *pb, while (n++ < read) total = (total << 8) | avio_r8(pb); + if (pb->eof_reached) { + eof_forbidden = 1; + goto err; + } + *number = total; return read; + +err: + pos = avio_tell(pb); + if (pb->error) { + av_log(matroska->ctx, AV_LOG_ERROR, + "Read error at pos. %"PRIu64" (0x%"PRIx64")\n", + pos, pos); + return pb->error; + } + if (eof_forbidden) { + av_log(matroska->ctx, AV_LOG_ERROR, "File ended prematurely " + "at pos. %"PRIu64" (0x%"PRIx64")\n", pos, pos); + return AVERROR(EIO); + } + return AVERROR_EOF; } /** @@ -844,7 +863,7 @@ static int ebml_read_num(MatroskaDemuxContext *matroska, AVIOContext *pb, static int ebml_read_length(MatroskaDemuxContext *matroska, AVIOContext *pb, uint64_t *number) { - int res = ebml_read_num(matroska, pb, 8, number); + int res = ebml_read_num(matroska, pb, 8, number, 1); if (res > 0 && *number + 1 == 1ULL << (7 * res)) *number = EBML_UNKNOWN_LENGTH; return res; @@ -986,7 +1005,7 @@ static int matroska_ebmlnum_uint(MatroskaDemuxContext *matroska, { AVIOContext pb; ffio_init_context(&pb, data, size, 0, NULL, NULL, NULL, NULL); - return ebml_read_num(matroska, &pb, FFMIN(size, 8), num); + return ebml_read_num(matroska, &pb, FFMIN(size, 8), num, 1); } /* @@ -1033,7 +1052,7 @@ static int ebml_parse(MatroskaDemuxContext *matroska, EbmlSyntax *syntax, { if (!matroska->current_id) { uint64_t id; - int res = ebml_read_num(matroska, matroska->ctx->pb, 4, &id); + int res = ebml_read_num(matroska, matroska->ctx->pb, 4, &id, 0); if (res < 0) { // in live mode, finish parsing if EOF is reached. return (matroska->is_live && matroska->ctx->pb->eof_reached && @@ -3326,7 +3345,6 @@ static int matroska_parse_block(MatroskaDemuxContext *matroska, AVBufferRef *buf int trust_default_duration = 1; if ((n = matroska_ebmlnum_uint(matroska, data, size, &num)) < 0) { - av_log(matroska->ctx, AV_LOG_ERROR, "EBML block data error\n"); return n; } data += n; @@ -3650,7 +3668,7 @@ static int webm_clusters_start_with_keyframe(AVFormatContext *s) AVPacket *pkt; avio_seek(s->pb, cluster_pos, SEEK_SET); // read cluster id and length - read = ebml_read_num(matroska, matroska->ctx->pb, 4, &cluster_id); + read = ebml_read_num(matroska, matroska->ctx->pb, 4, &cluster_id, 1); if (read < 0 || cluster_id != 0xF43B675) // done with all clusters break; read = ebml_read_length(matroska, matroska->ctx->pb, &cluster_length); @@ -3868,7 +3886,7 @@ static int webm_dash_manifest_cues(AVFormatContext *s, int64_t init_range) // cues_end is inclusive and the above sum is reduced by 1. uint64_t cues_length, cues_id; int bytes_read; - bytes_read = ebml_read_num (matroska, matroska->ctx->pb, 4, &cues_id); + bytes_read = ebml_read_num (matroska, matroska->ctx->pb, 4, &cues_id, 1); if (bytes_read < 0 || cues_id != (MATROSKA_ID_CUES & 0xfffffff)) return bytes_read < 0 ? bytes_read : AVERROR_INVALIDDATA; bytes_read = ebml_read_length(matroska, matroska->ctx->pb, &cues_length); |