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https://github.com/FFmpeg/FFmpeg.git
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90fc00a623
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.
168 lines
5.1 KiB
C
168 lines
5.1 KiB
C
/*
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* MicroDVD subtitle demuxer
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* Copyright (c) 2010 Aurelien Jacobs <aurel@gnuage.org>
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* Copyright (c) 2012 Clément Bœsch <u pkh me>
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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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#include "avformat.h"
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#include "internal.h"
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#include "subtitles.h"
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#include "libavutil/intreadwrite.h"
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#define MAX_LINESIZE 2048
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typedef struct {
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FFDemuxSubtitlesQueue q;
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} MicroDVDContext;
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static int microdvd_probe(AVProbeData *p)
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{
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unsigned char c;
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const uint8_t *ptr = p->buf;
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int i;
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if (AV_RB24(ptr) == 0xEFBBBF)
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ptr += 3; /* skip UTF-8 BOM */
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for (i=0; i<3; i++) {
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if (sscanf(ptr, "{%*d}{}%c", &c) != 1 &&
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sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 &&
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sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
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return 0;
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ptr += ff_subtitles_next_line(ptr);
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}
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return AVPROBE_SCORE_MAX;
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}
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static int64_t get_pts(const char *buf)
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{
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int frame;
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char c;
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if (sscanf(buf, "{%d}{%c", &frame, &c) == 2)
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return frame;
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return AV_NOPTS_VALUE;
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}
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static int get_duration(const char *buf)
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{
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int frame_start, frame_end;
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if (sscanf(buf, "{%d}{%d}", &frame_start, &frame_end) == 2)
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return frame_end - frame_start;
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return -1;
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}
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static int microdvd_read_header(AVFormatContext *s)
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{
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AVRational pts_info = (AVRational){ 2997, 125 }; /* default: 23.976 fps */
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MicroDVDContext *microdvd = s->priv_data;
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AVStream *st = avformat_new_stream(s, NULL);
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int i = 0;
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char line[MAX_LINESIZE];
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if (!st)
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return AVERROR(ENOMEM);
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while (!url_feof(s->pb)) {
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char *p = line;
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AVPacket *sub;
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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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if (!len)
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break;
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line[strcspn(line, "\r\n")] = 0;
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if (i++ < 3) {
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int frame;
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double fps;
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char c;
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if ((sscanf(line, "{%d}{}%6lf", &frame, &fps) == 2 ||
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sscanf(line, "{%d}{%*d}%6lf", &frame, &fps) == 2)
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&& frame <= 1 && fps > 3 && fps < 100)
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pts_info = av_d2q(fps, 100000);
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if (!st->codec->extradata && sscanf(line, "{DEFAULT}{}%c", &c) == 1) {
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st->codec->extradata = av_strdup(line + 11);
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if (!st->codec->extradata)
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return AVERROR(ENOMEM);
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st->codec->extradata_size = strlen(st->codec->extradata) + 1;
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continue;
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}
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}
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#define SKIP_FRAME_ID \
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p = strchr(p, '}'); \
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if (!p) { \
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av_log(s, AV_LOG_WARNING, "Invalid event \"%s\"" \
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" at line %d\n", line, i); \
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continue; \
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} \
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p++
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SKIP_FRAME_ID;
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SKIP_FRAME_ID;
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if (!*p)
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continue;
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sub = ff_subtitles_queue_insert(µdvd->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 = get_pts(line);
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sub->duration = get_duration(line);
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}
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ff_subtitles_queue_finalize(µdvd->q);
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avpriv_set_pts_info(st, 64, pts_info.den, pts_info.num);
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st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;
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st->codec->codec_id = AV_CODEC_ID_MICRODVD;
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return 0;
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}
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static int microdvd_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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MicroDVDContext *microdvd = s->priv_data;
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return ff_subtitles_queue_read_packet(µdvd->q, pkt);
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}
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static int microdvd_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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MicroDVDContext *microdvd = s->priv_data;
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return ff_subtitles_queue_seek(µdvd->q, s, stream_index,
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min_ts, ts, max_ts, flags);
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}
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static int microdvd_read_close(AVFormatContext *s)
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{
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MicroDVDContext *microdvd = s->priv_data;
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ff_subtitles_queue_clean(µdvd->q);
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return 0;
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}
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AVInputFormat ff_microdvd_demuxer = {
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.name = "microdvd",
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.long_name = NULL_IF_CONFIG_SMALL("MicroDVD subtitle format"),
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.priv_data_size = sizeof(MicroDVDContext),
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.read_probe = microdvd_probe,
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.read_header = microdvd_read_header,
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.read_packet = microdvd_read_packet,
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.read_seek2 = microdvd_read_seek,
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.read_close = microdvd_read_close,
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};
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