mirror of
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.
145 lines
4.2 KiB
C
145 lines
4.2 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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* MPlayer 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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} MPSubContext;
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static int mpsub_probe(AVProbeData *p)
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{
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const char *ptr = p->buf;
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const char *ptr_end = p->buf + p->buf_size;
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while (ptr < ptr_end) {
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int inc;
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if (!memcmp(ptr, "FORMAT=TIME", 11))
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return AVPROBE_SCORE_EXTENSION;
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if (!memcmp(ptr, "FORMAT=", 7))
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return AVPROBE_SCORE_EXTENSION / 3;
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inc = ff_subtitles_next_line(ptr);
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if (!inc)
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break;
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ptr += inc;
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}
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return 0;
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}
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static int mpsub_read_header(AVFormatContext *s)
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{
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MPSubContext *mpsub = s->priv_data;
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AVStream *st;
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AVBPrint buf;
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AVRational pts_info = (AVRational){ 100, 1 }; // ts based by default
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int res = 0;
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float multiplier = 100.0;
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float current_pts = 0;
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av_bprint_init(&buf, 0, AV_BPRINT_SIZE_UNLIMITED);
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while (!url_feof(s->pb)) {
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char line[1024];
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float start, duration;
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int fps, 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 (sscanf(line, "FORMAT=%d", &fps) == 1 && fps > 3 && fps < 100) {
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/* frame based timing */
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pts_info = (AVRational){ fps, 1 };
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multiplier = 1.0;
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} else if (sscanf(line, "%f %f", &start, &duration) == 2) {
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AVPacket *sub;
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const int64_t pos = avio_tell(s->pb);
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ff_subtitles_read_chunk(s->pb, &buf);
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if (buf.len) {
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sub = ff_subtitles_queue_insert(&mpsub->q, buf.str, buf.len, 0);
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if (!sub) {
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res = AVERROR(ENOMEM);
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goto end;
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}
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sub->pts = (int64_t)(current_pts + start*multiplier);
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sub->duration = (int)(duration * multiplier);
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current_pts += (start + duration) * multiplier;
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sub->pos = pos;
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}
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}
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}
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st = avformat_new_stream(s, NULL);
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if (!st)
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return AVERROR(ENOMEM);
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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_TEXT;
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ff_subtitles_queue_finalize(&mpsub->q);
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end:
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av_bprint_finalize(&buf, NULL);
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return res;
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}
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static int mpsub_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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MPSubContext *mpsub = s->priv_data;
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return ff_subtitles_queue_read_packet(&mpsub->q, pkt);
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}
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static int mpsub_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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MPSubContext *mpsub = s->priv_data;
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return ff_subtitles_queue_seek(&mpsub->q, s, stream_index,
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min_ts, ts, max_ts, flags);
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}
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static int mpsub_read_close(AVFormatContext *s)
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{
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MPSubContext *mpsub = s->priv_data;
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ff_subtitles_queue_clean(&mpsub->q);
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return 0;
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}
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AVInputFormat ff_mpsub_demuxer = {
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.name = "mpsub",
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.long_name = NULL_IF_CONFIG_SMALL("MPlayer subtitles"),
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.priv_data_size = sizeof(MPSubContext),
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.read_probe = mpsub_probe,
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.read_header = mpsub_read_header,
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.read_packet = mpsub_read_packet,
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.read_seek2 = mpsub_read_seek,
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.read_close = mpsub_read_close,
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.extensions = "sub",
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};
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