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/*
File: file_flv.c
Copyright (C) 2007,2014 Christophe GRENIER <grenier@cgsecurity.org>
This software is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License along
with this program; if not, write the Free Software Foundation, Inc., 51
Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#if !defined(SINGLE_FORMAT) || defined(SINGLE_FORMAT_flv)
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#include <stdio.h>
#include "types.h"
#include "filegen.h"
#include "common.h"
#include "log.h"
/*@ requires \valid(file_stat); */
static void register_header_check_flv(file_stat_t *file_stat);
const file_hint_t file_hint_flv= {
.extension="flv",
.description="Macromedia",
.max_filesize=PHOTOREC_MAX_FILE_SIZE,
.recover=1,
.enable_by_default=1,
.register_header_check=®ister_header_check_flv
};
struct flv_header
{
char signature[3];
uint8_t version;
uint8_t type_flags;
uint32_t data_offset;
} __attribute__ ((gcc_struct, __packed__));
struct flv_tag
{
uint32_t prev_tag_size;
uint8_t info;
uint8_t data_size[3];
uint8_t timestamp[3];
uint8_t timestamp_ext;
uint8_t streamID[3];
} __attribute__ ((gcc_struct, __packed__));
static uint32_t datasize=0;
/*@
@ requires buffer_size > 0;
@ requires (buffer_size&1)==0;
@ requires \valid_read(buffer+(0..buffer_size-1));
@ requires \valid(file_recovery);
@ requires file_recovery->data_check==&data_check_flv;
@ requires file_recovery->calculated_file_size <= PHOTOREC_MAX_FILE_SIZE;
@ requires \separated(buffer + (..), file_recovery);
@ ensures \result == DC_CONTINUE || \result == DC_STOP || \result == DC_ERROR;
@ assigns file_recovery->calculated_file_size, datasize;
@*/
static data_check_t data_check_flv(const unsigned char *buffer, const unsigned int buffer_size, file_recovery_t *file_recovery)
{
/*@
@ loop assigns file_recovery->calculated_file_size, datasize;
@*/
while(file_recovery->calculated_file_size + buffer_size/2 >= file_recovery->file_size &&
file_recovery->calculated_file_size + 15 < file_recovery->file_size + buffer_size/2)
{
const unsigned int i=file_recovery->calculated_file_size + buffer_size/2 - file_recovery->file_size;
/*@ assert 0 <= i < buffer_size - 15; */
const struct flv_tag *tag=(const struct flv_tag *)&buffer[i];
/*@ assert \valid_read(tag); */
#ifdef DEBUG_FLV
log_info("cfs=0x%llx datasize=%u\n", (long long unsigned)file_recovery->calculated_file_size, datasize);
#endif
if((be32(tag->prev_tag_size)==0 && file_recovery->calculated_file_size < buffer_size/2) ||
be32(tag->prev_tag_size)==11+datasize)
{
datasize=(tag->data_size[0]<<16) | (tag->data_size[1]<<8) | tag->data_size[2];
if((tag->info&0xc0)!=0 || datasize==0
|| tag->streamID[0]!=0 || tag->streamID[1]!=0 || tag->streamID[2]!=0 )
{
file_recovery->calculated_file_size+=4;
return DC_STOP;
}
/* 4+11=15*/
file_recovery->calculated_file_size+=(uint64_t)15+datasize;
}
else
return DC_ERROR;
}
return DC_CONTINUE;
}
/*@
@ requires buffer_size >= sizeof(struct flv_header);
@ requires \valid_read(buffer+(0..buffer_size-1));
@ requires valid_file_recovery(file_recovery);
@ requires \valid(file_recovery_new);
@ requires file_recovery_new->blocksize > 0;
@ requires separation: \separated(&file_hint_flv, buffer+(..), file_recovery, file_recovery_new);
@ assigns *file_recovery_new;
@ ensures \result!=0 ==> valid_file_recovery(file_recovery_new);
@*/
static int header_check_flv(const unsigned char *buffer, const unsigned int buffer_size, const unsigned int safe_header_only, const file_recovery_t *file_recovery, file_recovery_t *file_recovery_new)
{
const struct flv_header *flv=(const struct flv_header *)buffer;
const unsigned int data_offset=be32(flv->data_offset);
if((flv->type_flags & 0xfa)==0 && data_offset>=9)
{
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_flv.extension;
if(file_recovery_new->blocksize < 15)
return 1;
file_recovery_new->calculated_file_size=data_offset;
file_recovery_new->data_check=&data_check_flv;
file_recovery_new->file_check=&file_check_size;
return 1;
}
return 0;
}
static void register_header_check_flv(file_stat_t *file_stat)
{
static const unsigned char flv_header[4]= {'F', 'L', 'V', 0x01};
register_header_check(0, flv_header,sizeof(flv_header), &header_check_flv, file_stat);
}
#endif
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