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![Clément Bœsch](/assets/img/avatar_default.png)
This fixes a bunch of possible overread in avformat with the idiom p += strcspn(p, "\n") + 1 (strcspn() can focus on the trailing '\0' if no '\n' is found, so the +1 leads to an overread). Note on lavf/matroskaenc: no extra subtitles.o Makefile dependency is added because only the header is required for ff_subtitles_next_line(). Note on lavf/mpsubdec: code gets slightly complex to avoid an infinite loop in the probing since there is no more forced increment.
147 lines
4.0 KiB
C
147 lines
4.0 KiB
C
/*
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* Copyright (c) 2012 Clément Bœsch
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg 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 GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* MPL2 subtitles format demuxer
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*/
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#include "avformat.h"
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#include "internal.h"
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#include "subtitles.h"
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typedef struct {
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FFDemuxSubtitlesQueue q;
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} MPL2Context;
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static int mpl2_probe(AVProbeData *p)
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{
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int i;
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char c;
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int64_t start, end;
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const unsigned char *ptr = p->buf;
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const unsigned char *ptr_end = ptr + p->buf_size;
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for (i = 0; i < 2; i++) {
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if (sscanf(ptr, "[%"SCNd64"][%"SCNd64"]%c", &start, &end, &c) != 3 &&
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sscanf(ptr, "[%"SCNd64"][]%c", &start, &c) != 2)
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return 0;
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ptr += ff_subtitles_next_line(ptr);
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if (ptr >= ptr_end)
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return 0;
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}
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return AVPROBE_SCORE_MAX;
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}
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static int read_ts(char **line, int64_t *pts_start, int *duration)
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{
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char c;
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int len;
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int64_t end;
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if (sscanf(*line, "[%"SCNd64"][]%c%n",
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pts_start, &c, &len) >= 2) {
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*duration = -1;
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*line += len - 1;
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return 0;
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}
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if (sscanf(*line, "[%"SCNd64"][%"SCNd64"]%c%n",
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pts_start, &end, &c, &len) >= 3) {
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*duration = end - *pts_start;
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*line += len - 1;
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return 0;
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}
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return -1;
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}
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static int mpl2_read_header(AVFormatContext *s)
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{
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MPL2Context *mpl2 = s->priv_data;
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AVStream *st = avformat_new_stream(s, NULL);
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int res = 0;
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if (!st)
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return AVERROR(ENOMEM);
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avpriv_set_pts_info(st, 64, 1, 10);
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st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
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st->codec->codec_id = AV_CODEC_ID_MPL2;
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while (!url_feof(s->pb)) {
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char line[4096];
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char *p = line;
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const int64_t pos = avio_tell(s->pb);
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int len = ff_get_line(s->pb, line, sizeof(line));
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int64_t pts_start;
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int duration;
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if (!len)
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break;
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line[strcspn(line, "\r\n")] = 0;
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if (!read_ts(&p, &pts_start, &duration)) {
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AVPacket *sub;
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sub = ff_subtitles_queue_insert(&mpl2->q, p, strlen(p), 0);
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if (!sub)
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return AVERROR(ENOMEM);
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sub->pos = pos;
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sub->pts = pts_start;
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sub->duration = duration;
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}
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}
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ff_subtitles_queue_finalize(&mpl2->q);
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return res;
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}
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static int mpl2_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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MPL2Context *mpl2 = s->priv_data;
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return ff_subtitles_queue_read_packet(&mpl2->q, pkt);
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}
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static int mpl2_read_seek(AVFormatContext *s, int stream_index,
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int64_t min_ts, int64_t ts, int64_t max_ts, int flags)
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{
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MPL2Context *mpl2 = s->priv_data;
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return ff_subtitles_queue_seek(&mpl2->q, s, stream_index,
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min_ts, ts, max_ts, flags);
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}
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static int mpl2_read_close(AVFormatContext *s)
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{
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MPL2Context *mpl2 = s->priv_data;
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ff_subtitles_queue_clean(&mpl2->q);
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return 0;
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}
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AVInputFormat ff_mpl2_demuxer = {
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.name = "mpl2",
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.long_name = NULL_IF_CONFIG_SMALL("MPL2 subtitles"),
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.priv_data_size = sizeof(MPL2Context),
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.read_probe = mpl2_probe,
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.read_header = mpl2_read_header,
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.read_packet = mpl2_read_packet,
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.read_seek2 = mpl2_read_seek,
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.read_close = mpl2_read_close,
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.extensions = "txt,mpl2",
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};
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