mirror of
https://github.com/mpv-player/mpv
synced 2024-12-25 08:12:17 +00:00
c15957b43a
Seems like a good idea.
627 lines
19 KiB
C
627 lines
19 KiB
C
/*
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* native ebml reader for the Matroska demuxer
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* new parser copyright (c) 2010 Uoti Urpala
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* copyright (c) 2004 Aurelien Jacobs <aurel@gnuage.org>
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* based on the one written by Ronald Bultje for gstreamer
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*
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* This file is part of MPlayer.
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*
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* MPlayer is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* MPlayer is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with MPlayer; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include "config.h"
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#include <stdlib.h>
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#include <stdbool.h>
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#include <inttypes.h>
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#include <stddef.h>
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#include <assert.h>
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#include <libavutil/intfloat.h>
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#include <libavutil/common.h>
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#include "talloc.h"
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#include "ebml.h"
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#include "stream/stream.h"
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#include "osdep/mpbswap.h"
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#include "common/msg.h"
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// Whether the id is a known Matroska level 1 element (allowed as element on
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// global file level, after the level 0 MATROSKA_ID_SEGMENT).
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// This (intentionally) doesn't include "global" elements.
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bool ebml_is_mkv_level1_id(uint32_t id)
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{
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switch (id) {
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case MATROSKA_ID_SEEKHEAD:
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case MATROSKA_ID_INFO:
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case MATROSKA_ID_CLUSTER:
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case MATROSKA_ID_TRACKS:
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case MATROSKA_ID_CUES:
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case MATROSKA_ID_ATTACHMENTS:
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case MATROSKA_ID_CHAPTERS:
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case MATROSKA_ID_TAGS:
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return true;
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default:
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return false;
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}
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}
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/*
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* Read: the element content data ID.
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* Return: the ID.
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*/
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uint32_t ebml_read_id(stream_t *s)
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{
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int i, len_mask = 0x80;
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uint32_t id;
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for (i = 0, id = stream_read_char(s); i < 4 && !(id & len_mask); i++)
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len_mask >>= 1;
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if (i >= 4)
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return EBML_ID_INVALID;
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while (i--)
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id = (id << 8) | stream_read_char(s);
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return id;
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}
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/*
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* Read a variable length unsigned int.
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*/
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uint64_t ebml_read_vlen_uint(bstr *buffer)
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{
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int i, j, num_ffs = 0, len_mask = 0x80;
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uint64_t num;
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if (buffer->len == 0)
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return EBML_UINT_INVALID;
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for (i = 0, num = buffer->start[0]; i < 8 && !(num & len_mask); i++)
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len_mask >>= 1;
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if (i >= 8)
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return EBML_UINT_INVALID;
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j = i + 1;
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if ((int) (num &= (len_mask - 1)) == len_mask - 1)
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num_ffs++;
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if (j > buffer->len)
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return EBML_UINT_INVALID;
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for (int n = 0; n < i; n++) {
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num = (num << 8) | buffer->start[n + 1];
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if ((num & 0xFF) == 0xFF)
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num_ffs++;
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}
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if (j == num_ffs)
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return EBML_UINT_INVALID;
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buffer->start += j;
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buffer->len -= j;
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return num;
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}
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/*
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* Read a variable length signed int.
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*/
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int64_t ebml_read_vlen_int(bstr *buffer)
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{
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uint64_t unum;
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int l;
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/* read as unsigned number first */
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size_t len = buffer->len;
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unum = ebml_read_vlen_uint(buffer);
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if (unum == EBML_UINT_INVALID)
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return EBML_INT_INVALID;
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l = len - buffer->len;
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return unum - ((1 << ((7 * l) - 1)) - 1);
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}
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/*
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* Read: element content length.
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*/
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uint64_t ebml_read_length(stream_t *s)
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{
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int i, j, num_ffs = 0, len_mask = 0x80;
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uint64_t len;
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for (i = 0, len = stream_read_char(s); i < 8 && !(len & len_mask); i++)
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len_mask >>= 1;
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if (i >= 8)
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return EBML_UINT_INVALID;
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j = i + 1;
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if ((int) (len &= (len_mask - 1)) == len_mask - 1)
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num_ffs++;
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while (i--) {
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len = (len << 8) | stream_read_char(s);
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if ((len & 0xFF) == 0xFF)
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num_ffs++;
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}
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if (j == num_ffs)
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return EBML_UINT_INVALID;
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if (len >= 1ULL<<63) // Can happen if stream_read_char returns EOF
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return EBML_UINT_INVALID;
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return len;
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}
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/*
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* Read the next element as an unsigned int.
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*/
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uint64_t ebml_read_uint(stream_t *s)
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{
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uint64_t len, value = 0;
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len = ebml_read_length(s);
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if (len == EBML_UINT_INVALID || len < 1 || len > 8)
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return EBML_UINT_INVALID;
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while (len--)
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value = (value << 8) | stream_read_char(s);
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return value;
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}
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/*
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* Read the next element as a signed int.
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*/
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int64_t ebml_read_int(stream_t *s)
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{
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int64_t value = 0;
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uint64_t len;
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int l;
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len = ebml_read_length(s);
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if (len == EBML_UINT_INVALID || len < 1 || len > 8)
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return EBML_INT_INVALID;
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len--;
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l = stream_read_char(s);
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if (l & 0x80)
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value = -1;
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value = (value << 8) | l;
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while (len--)
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value = (value << 8) | stream_read_char(s);
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return value;
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}
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/*
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* Skip the current element.
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* end: the end of the parent element or -1 (for robust error handling)
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*/
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int ebml_read_skip(struct mp_log *log, int64_t end, stream_t *s)
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{
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uint64_t len;
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int64_t pos = stream_tell(s);
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len = ebml_read_length(s);
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if (len == EBML_UINT_INVALID)
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goto invalid;
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int64_t pos2 = stream_tell(s);
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if (len >= INT64_MAX - pos2 || (end > 0 && pos2 + len > end))
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goto invalid;
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if (!stream_skip(s, len))
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goto invalid;
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return 0;
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invalid:
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mp_err(log, "Invalid EBML length at position %"PRId64"\n", pos);
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stream_seek(s, pos);
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return 1;
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}
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/*
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* Skip to (probable) next cluster (MATROSKA_ID_CLUSTER) element start position.
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*/
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int ebml_resync_cluster(struct mp_log *log, stream_t *s)
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{
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int64_t pos = stream_tell(s);
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uint32_t last_4_bytes = 0;
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mp_err(log, "Corrupt file detected. "
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"Trying to resync starting from position %"PRId64"...\n", pos);
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while (!s->eof) {
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// Assumes MATROSKA_ID_CLUSTER is 4 bytes, with no 0 bytes.
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if (last_4_bytes == MATROSKA_ID_CLUSTER) {
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mp_err(log, "Cluster found at %"PRId64".\n", pos - 4);
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stream_seek(s, pos - 4);
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return 0;
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}
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last_4_bytes = (last_4_bytes << 8) | stream_read_char(s);
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pos++;
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}
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return -1;
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}
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#define EVALARGS(F, ...) F(__VA_ARGS__)
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#define E(str, N, type) const struct ebml_elem_desc ebml_ ## N ## _desc = { str, type };
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#define E_SN(str, count, N) const struct ebml_elem_desc ebml_ ## N ## _desc = { str, EBML_TYPE_SUBELEMENTS, sizeof(struct ebml_ ## N), count, (const struct ebml_field_desc[]){
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#define E_S(str, count) EVALARGS(E_SN, str, count, N)
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#define FN(id, name, multiple, N) { id, multiple, offsetof(struct ebml_ ## N, name), offsetof(struct ebml_ ## N, n_ ## name), &ebml_##name##_desc},
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#define F(id, name, multiple) EVALARGS(FN, id, name, multiple, N)
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#include "ebml_defs.c"
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#undef EVALARGS
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#undef SN
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#undef S
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#undef FN
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#undef F
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// Used to read/write pointers to different struct types
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struct generic;
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#define generic_struct struct generic
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static uint32_t ebml_parse_id(uint8_t *data, int *length)
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{
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int len = 1;
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uint32_t id = *data++;
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for (int len_mask = 0x80; !(id & len_mask); len_mask >>= 1) {
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len++;
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if (len > 4) {
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*length = -1;
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return EBML_ID_INVALID;
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}
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}
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*length = len;
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while (--len)
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id = (id << 8) | *data++;
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return id;
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}
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static uint64_t parse_vlen(uint8_t *data, int *length, bool is_length)
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{
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uint64_t r = *data++;
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int len = 1;
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int len_mask;
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for (len_mask = 0x80; !(r & len_mask); len_mask >>= 1) {
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len++;
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if (len > 8) {
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*length = -1;
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return -1;
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}
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}
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r &= len_mask - 1;
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int num_allones = 0;
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if (r == len_mask - 1)
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num_allones++;
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for (int i = 1; i < len; i++) {
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if (*data == 255)
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num_allones++;
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r = (r << 8) | *data++;
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}
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if (is_length && num_allones == len) {
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// According to Matroska specs this means "unknown length"
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// Could be supported if there are any actual files using it
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*length = -1;
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return -1;
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}
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*length = len;
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return r;
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}
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static uint64_t ebml_parse_length(uint8_t *data, int *length)
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{
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return parse_vlen(data, length, true);
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}
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static uint64_t ebml_parse_uint(uint8_t *data, int length)
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{
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assert(length >= 1 && length <= 8);
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uint64_t r = 0;
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while (length--)
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r = (r << 8) + *data++;
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return r;
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}
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static int64_t ebml_parse_sint(uint8_t *data, int length)
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{
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assert(length >=1 && length <= 8);
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int64_t r = 0;
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if (*data & 0x80)
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r = -1;
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while (length--)
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r = (r << 8) | *data++;
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return r;
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}
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static double ebml_parse_float(uint8_t *data, int length)
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{
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assert(length == 4 || length == 8);
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uint64_t i = ebml_parse_uint(data, length);
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if (length == 4)
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return av_int2float(i);
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else
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return av_int2double(i);
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}
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// target must be initialized to zero
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static void ebml_parse_element(struct ebml_parse_ctx *ctx, void *target,
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uint8_t *data, int size,
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const struct ebml_elem_desc *type, int level)
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{
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assert(type->type == EBML_TYPE_SUBELEMENTS);
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assert(level < 8);
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MP_DBG(ctx, "%.*sParsing element %s\n", level, " ", type->name);
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char *s = target;
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uint8_t *end = data + size;
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uint8_t *p = data;
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int num_elems[MAX_EBML_SUBELEMENTS] = {0};
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while (p < end) {
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uint8_t *startp = p;
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int len;
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uint32_t id = ebml_parse_id(p, &len);
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if (len > end - p)
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goto past_end_error;
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if (len < 0) {
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MP_DBG(ctx, "Error parsing subelement id\n");
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goto other_error;
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}
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p += len;
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uint64_t length = ebml_parse_length(p, &len);
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if (len > end - p)
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goto past_end_error;
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if (len < 0) {
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MP_DBG(ctx, "Error parsing subelement length\n");
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goto other_error;
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}
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p += len;
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int field_idx = -1;
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for (int i = 0; i < type->field_count; i++)
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if (type->fields[i].id == id) {
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field_idx = i;
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num_elems[i]++;
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if (num_elems[i] >= 0x70000000) {
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MP_ERR(ctx, "Too many EBML subelements.\n");
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goto other_error;
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}
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break;
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}
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if (length > end - p) {
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if (field_idx >= 0 && type->fields[field_idx].desc->type
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!= EBML_TYPE_SUBELEMENTS) {
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MP_DBG(ctx, "Subelement content goes "
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"past end of containing element\n");
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goto other_error;
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}
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// Try to parse what is possible from inside this partial element
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ctx->has_errors = true;
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length = end - p;
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}
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p += length;
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continue;
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past_end_error:
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MP_DBG(ctx, "Subelement headers go past end of containing element\n");
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other_error:
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ctx->has_errors = true;
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end = startp;
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break;
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}
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for (int i = 0; i < type->field_count; i++)
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if (num_elems[i] && type->fields[i].multiple) {
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char *ptr = s + type->fields[i].offset;
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switch (type->fields[i].desc->type) {
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case EBML_TYPE_SUBELEMENTS: {
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size_t max = 1000000000 / type->fields[i].desc->size;
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if (num_elems[i] > max) {
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MP_ERR(ctx, "Too many subelements.\n");
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num_elems[i] = max;
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}
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int sz = num_elems[i] * type->fields[i].desc->size;
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*(generic_struct **) ptr = talloc_zero_size(ctx->talloc_ctx, sz);
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break;
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}
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case EBML_TYPE_UINT:
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*(uint64_t **) ptr = talloc_zero_array(ctx->talloc_ctx,
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uint64_t, num_elems[i]);
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break;
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case EBML_TYPE_SINT:
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*(int64_t **) ptr = talloc_zero_array(ctx->talloc_ctx,
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int64_t, num_elems[i]);
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break;
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case EBML_TYPE_FLOAT:
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*(double **) ptr = talloc_zero_array(ctx->talloc_ctx,
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double, num_elems[i]);
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break;
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case EBML_TYPE_STR:
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case EBML_TYPE_BINARY:
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*(struct bstr **) ptr = talloc_zero_array(ctx->talloc_ctx,
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struct bstr,
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num_elems[i]);
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break;
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case EBML_TYPE_EBML_ID:
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*(int32_t **) ptr = talloc_zero_array(ctx->talloc_ctx,
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uint32_t, num_elems[i]);
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break;
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default:
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abort();
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}
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}
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while (data < end) {
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int len;
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uint32_t id = ebml_parse_id(data, &len);
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assert(len >= 0 && len <= end - data);
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data += len;
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uint64_t length = ebml_parse_length(data, &len);
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assert(len >= 0 && len <= end - data);
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data += len;
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if (length > end - data) {
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// Try to parse what is possible from inside this partial element
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length = end - data;
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MP_DBG(ctx, "Next subelement content goes "
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"past end of containing element, will be truncated\n");
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}
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int field_idx = -1;
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for (int i = 0; i < type->field_count; i++)
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if (type->fields[i].id == id) {
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field_idx = i;
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break;
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}
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if (field_idx < 0) {
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if (id == 0xec)
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MP_DBG(ctx, "%.*sIgnoring Void element "
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"size: %"PRIu64"\n", level+1, " ", length);
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else if (id == 0xbf)
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MP_DBG(ctx, "%.*sIgnoring CRC-32 "
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"element size: %"PRIu64"\n", level+1, " ",
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length);
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else
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MP_DBG(ctx, "Ignoring unrecognized "
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"subelement. ID: %x size: %"PRIu64"\n", id, length);
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data += length;
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continue;
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}
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const struct ebml_field_desc *fd = &type->fields[field_idx];
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const struct ebml_elem_desc *ed = fd->desc;
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bool multiple = fd->multiple;
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int *countptr = (int *) (s + fd->count_offset);
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if (*countptr >= num_elems[field_idx]) {
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// Shouldn't happen with on any sane file without bugs
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MP_ERR(ctx, "Too many subelems?\n");
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ctx->has_errors = true;
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data += length;
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continue;
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}
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if (*countptr > 0 && !multiple) {
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MP_DBG(ctx, "Another subelement of type "
|
|
"%x %s (size: %"PRIu64"). Only one allowed. Ignoring.\n",
|
|
id, ed->name, length);
|
|
ctx->has_errors = true;
|
|
data += length;
|
|
continue;
|
|
}
|
|
MP_DBG(ctx, "%.*sParsing %x %s size: %"PRIu64
|
|
" value: ", level+1, " ", id, ed->name, length);
|
|
|
|
char *fieldptr = s + fd->offset;
|
|
switch (ed->type) {
|
|
case EBML_TYPE_SUBELEMENTS:
|
|
MP_DBG(ctx, "subelements\n");
|
|
char *subelptr;
|
|
if (multiple) {
|
|
char *array_start = (char *) *(generic_struct **) fieldptr;
|
|
subelptr = array_start + *countptr * ed->size;
|
|
} else
|
|
subelptr = fieldptr;
|
|
ebml_parse_element(ctx, subelptr, data, length, ed, level + 1);
|
|
break;
|
|
|
|
case EBML_TYPE_UINT:;
|
|
uint64_t *uintptr;
|
|
#define GETPTR(subelptr, fieldtype) \
|
|
if (multiple) \
|
|
subelptr = *(fieldtype **) fieldptr + *countptr; \
|
|
else \
|
|
subelptr = (fieldtype *) fieldptr
|
|
GETPTR(uintptr, uint64_t);
|
|
if (length < 1 || length > 8) {
|
|
MP_DBG(ctx, "uint invalid length %"PRIu64"\n", length);
|
|
goto error;
|
|
}
|
|
*uintptr = ebml_parse_uint(data, length);
|
|
MP_DBG(ctx, "uint %"PRIu64"\n", *uintptr);
|
|
break;
|
|
|
|
case EBML_TYPE_SINT:;
|
|
int64_t *sintptr;
|
|
GETPTR(sintptr, int64_t);
|
|
if (length < 1 || length > 8) {
|
|
MP_DBG(ctx, "sint invalid length %"PRIu64"\n", length);
|
|
goto error;
|
|
}
|
|
*sintptr = ebml_parse_sint(data, length);
|
|
MP_DBG(ctx, "sint %"PRId64"\n", *sintptr);
|
|
break;
|
|
|
|
case EBML_TYPE_FLOAT:;
|
|
double *floatptr;
|
|
GETPTR(floatptr, double);
|
|
if (length != 4 && length != 8) {
|
|
MP_DBG(ctx, "float invalid length %"PRIu64"\n", length);
|
|
goto error;
|
|
}
|
|
*floatptr = ebml_parse_float(data, length);
|
|
MP_DBG(ctx, "float %f\n", *floatptr);
|
|
break;
|
|
|
|
case EBML_TYPE_STR:
|
|
case EBML_TYPE_BINARY:;
|
|
if (length > 0x80000000) {
|
|
MP_ERR(ctx, "Not reading overly long EBML element.\n");
|
|
break;
|
|
}
|
|
struct bstr *strptr;
|
|
GETPTR(strptr, struct bstr);
|
|
strptr->start = data;
|
|
strptr->len = length;
|
|
if (ed->type == EBML_TYPE_STR)
|
|
MP_DBG(ctx, "string \"%.*s\"\n", BSTR_P(*strptr));
|
|
else
|
|
MP_DBG(ctx, "binary %zd bytes\n", strptr->len);
|
|
break;
|
|
|
|
case EBML_TYPE_EBML_ID:;
|
|
uint32_t *idptr;
|
|
GETPTR(idptr, uint32_t);
|
|
*idptr = ebml_parse_id(data, &len);
|
|
if (len != length) {
|
|
MP_DBG(ctx, "ebml_id broken value\n");
|
|
goto error;
|
|
}
|
|
MP_DBG(ctx, "ebml_id %x\n", (unsigned)*idptr);
|
|
break;
|
|
default:
|
|
abort();
|
|
}
|
|
*countptr += 1;
|
|
error:
|
|
data += length;
|
|
}
|
|
}
|
|
|
|
// target must be initialized to zero
|
|
int ebml_read_element(struct stream *s, struct ebml_parse_ctx *ctx,
|
|
void *target, const struct ebml_elem_desc *desc)
|
|
{
|
|
ctx->has_errors = false;
|
|
int msglevel = ctx->no_error_messages ? MSGL_DEBUG : MSGL_WARN;
|
|
uint64_t length = ebml_read_length(s);
|
|
if (s->eof) {
|
|
MP_MSG(ctx, msglevel, "Unexpected end of file "
|
|
"- partial or corrupt file?\n");
|
|
return -1;
|
|
}
|
|
if (length > 1000000000) {
|
|
MP_MSG(ctx, msglevel, "Refusing to read element over 100 MB in size\n");
|
|
return -1;
|
|
}
|
|
ctx->talloc_ctx = talloc_size(NULL, length + 8);
|
|
int read_len = stream_read(s, ctx->talloc_ctx, length);
|
|
if (read_len < length)
|
|
MP_MSG(ctx, msglevel, "Unexpected end of file - partial or corrupt file?\n");
|
|
ebml_parse_element(ctx, target, ctx->talloc_ctx, read_len, desc, 0);
|
|
if (ctx->has_errors)
|
|
MP_MSG(ctx, msglevel, "Error parsing element %s\n", desc->name);
|
|
return 0;
|
|
}
|