Fixes: Null pointer dereference Fixes: CVE-2017-9608 Found-by: Yihan Lian Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
		
			
				
	
	
		
			144 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			144 lines
		
	
	
		
			4.3 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * DNxHD/VC-3 parser
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 * Copyright (c) 2008 Baptiste Coudurier <baptiste.coudurier@free.fr>
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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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 * DNxHD/VC-3 parser
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 */
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#include "parser.h"
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#include "dnxhddata.h"
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typedef struct {
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    ParseContext pc;
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    int cur_byte;
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    int remaining;
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    int w, h;
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} DNXHDParserContext;
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static int dnxhd_find_frame_end(DNXHDParserContext *dctx,
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                                const uint8_t *buf, int buf_size)
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{
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    ParseContext *pc = &dctx->pc;
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    uint64_t state = pc->state64;
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    int pic_found = pc->frame_start_found;
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    int i = 0;
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    if (!pic_found) {
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        for (i = 0; i < buf_size; i++) {
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            state = (state << 8) | buf[i];
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            if (ff_dnxhd_check_header_prefix(state & 0xffffffffff00LL) != 0) {
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                i++;
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                pic_found = 1;
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                dctx->cur_byte = 0;
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                dctx->remaining = 0;
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                break;
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            }
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        }
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    }
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    if (pic_found && !dctx->remaining) {
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        if (!buf_size) /* EOF considered as end of frame */
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            return 0;
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        for (; i < buf_size; i++) {
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            dctx->cur_byte++;
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            state = (state << 8) | buf[i];
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            if (dctx->cur_byte == 24) {
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                dctx->h = (state >> 32) & 0xFFFF;
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            } else if (dctx->cur_byte == 26) {
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                dctx->w = (state >> 32) & 0xFFFF;
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            } else if (dctx->cur_byte == 42) {
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                int cid = (state >> 32) & 0xFFFFFFFF;
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                int remaining;
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                if (cid <= 0)
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                    continue;
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                remaining = avpriv_dnxhd_get_frame_size(cid);
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                if (remaining <= 0) {
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                    remaining = ff_dnxhd_get_hr_frame_size(cid, dctx->w, dctx->h);
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                    if (remaining <= 0)
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                        continue;
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                }
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                dctx->remaining = remaining;
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                if (buf_size - i + 47 >= dctx->remaining) {
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                    int remaining = dctx->remaining;
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                    pc->frame_start_found = 0;
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                    pc->state64 = -1;
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                    dctx->cur_byte = 0;
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                    dctx->remaining = 0;
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                    return remaining;
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                } else {
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                    dctx->remaining -= buf_size;
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                }
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            }
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        }
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    } else if (pic_found) {
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        if (dctx->remaining > buf_size) {
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            dctx->remaining -= buf_size;
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        } else {
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            int remaining = dctx->remaining;
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            pc->frame_start_found = 0;
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            pc->state64 = -1;
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            dctx->cur_byte = 0;
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            dctx->remaining = 0;
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            return remaining;
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        }
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    }
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    pc->frame_start_found = pic_found;
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    pc->state64 = state;
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    return END_NOT_FOUND;
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}
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static int dnxhd_parse(AVCodecParserContext *s,
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                       AVCodecContext *avctx,
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                       const uint8_t **poutbuf, int *poutbuf_size,
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                       const uint8_t *buf, int buf_size)
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{
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    DNXHDParserContext *dctx = s->priv_data;
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    ParseContext *pc = &dctx->pc;
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    int next;
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    if (s->flags & PARSER_FLAG_COMPLETE_FRAMES) {
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        next = buf_size;
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    } else {
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        next = dnxhd_find_frame_end(dctx, buf, buf_size);
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        if (ff_combine_frame(pc, next, &buf, &buf_size) < 0) {
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            *poutbuf      = NULL;
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            *poutbuf_size = 0;
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            return buf_size;
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        }
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    }
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    *poutbuf      = buf;
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    *poutbuf_size = buf_size;
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    return next;
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}
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AVCodecParser ff_dnxhd_parser = {
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    .codec_ids      = { AV_CODEC_ID_DNXHD },
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    .priv_data_size = sizeof(DNXHDParserContext),
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    .parser_parse   = dnxhd_parse,
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    .parser_close   = ff_parse_close,
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};
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