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/*
File: file_ace.c
Copyright (C) 2007 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_ace)
#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"
#include "crc.h"
#if defined(__FRAMAC__)
#include "__fc_builtin.h"
#endif
/* #define DEBUG_ACE */
/*@
@ requires valid_register_header_check(file_stat);
@*/
static void register_header_check_ace(file_stat_t *file_stat);
const file_hint_t file_hint_ace= {
.extension="ace",
.description="ACE archive",
.max_filesize=PHOTOREC_MAX_FILE_SIZE,
.recover=1,
.enable_by_default=1,
.register_header_check=®ister_header_check_ace
};
struct header_ace {
uint16_t crc16; /** Lower 16bits of CRC32 over block up from HEAD_TYPE */
uint16_t size; /** Size of the block from HEAD_TYPE
up to the beginning of the ADDSIZE block */
uint8_t type; /** indicates type of block */
uint16_t flags; /** flags related to the block and its content
for all blocks these flags are valid.
bit 0 indicates if field add size is preset */
uint32_t addsize; /** an optional field which represents the size of
an additional block without specified structure */
} __attribute__ ((gcc_struct, __packed__));
typedef struct header_ace ace_header_t;
#define BUF_SIZE 4096
/*@
@ requires \valid(handle);
@ requires \separated(handle, &errno, &Frama_C_entropy_source);
@ assigns *handle, errno;
@ assigns Frama_C_entropy_source;
@*/
static int check_ace_crc(FILE *handle, const unsigned int len, const unsigned int crc32_low)
{
char buffer[BUF_SIZE];
uint32_t crc32=0xFFFFFFFF;
unsigned int remaining=len;
/*@
@ loop assigns *handle, errno;
@ loop assigns Frama_C_entropy_source;
@ loop assigns buffer[0 .. BUF_SIZE-1], crc32, remaining;
@ loop variant remaining;
@*/
while (remaining>0)
{
const unsigned int count = ((remaining>BUF_SIZE) ? BUF_SIZE : remaining);
if(fread(buffer, 1, count, handle) != count)
{
#ifdef DEBUG_ACE
log_info("file_ace: truncated file\n");
#endif
return 1;
}
#ifdef __FRAMAC__
Frama_C_make_unknown(&buffer, sizeof(buffer));
#endif
crc32=get_crc32(buffer, count, crc32);
remaining -= count;
}
if (crc32_low != (crc32&0xFFFF))
{
#ifdef DEBUG_ACE
log_info("file_ace: bad CRC: %04X vs %04X\n", crc32_low, crc32&0xFFFF);
#endif
return 1;
}
return 0;
}
/*@
@ requires file_recovery->file_check == &file_check_ace;
@ requires valid_file_check_param(file_recovery);
@ ensures valid_file_check_result(file_recovery);
@ assigns *file_recovery->handle, errno, file_recovery->file_size, file_recovery->offset_error, file_recovery->offset_ok;
@ assigns Frama_C_entropy_source;
@*/
static void file_check_ace(file_recovery_t *file_recovery)
{
file_recovery->offset_error = 0;
file_recovery->offset_ok = 0;
file_recovery->file_size = 0;
if(my_fseek(file_recovery->handle, 0, SEEK_SET)<0)
return ;
/*@
@ loop assigns *file_recovery->handle, errno, file_recovery->file_size, file_recovery->offset_error;
@ loop assigns Frama_C_entropy_source;
@ loop variant 0x8000000000000000-0x100000000 - file_recovery->file_size;
@*/
while (!feof(file_recovery->handle))
{
char buffer[sizeof(ace_header_t)];
const ace_header_t *h=(const ace_header_t *)&buffer;
if(fread(&buffer, sizeof(buffer), 1, file_recovery->handle)!= 1)
{
return ;
}
/*@ assert \initialized(&buffer + (0 .. sizeof(buffer)-1)); */
#ifdef DEBUG_ACE
log_info("file_ace: Block header at 0x%08lx: CRC16=0x%04X size=%u type=%u"
" flags=0x%04X addsize=%u\n",
(long unsigned) file_recovery->file_size,
le16(h->crc16), le16(h->size), h->type, le16(h->flags),
(le16(h->flags)&1) ? le32(h->addsize):0);
#endif
/* Type 0=Archive header, 1=File block, 2=Recovery Record, 5 new_recovery ? */
if (h->type==0 && le16(h->size)==0)
{
return ;
}
if (h->type!=0 && h->type!=1 && h->type!=2 && h->type!=5)
{
#ifdef DEBUG_ACE
log_info("file_ace: Invalid block type %u\n", h->type);
#endif
return ;
}
/* Minimal size is type+flags */
if (le16(h->size) < 1U + 2U)
{
#ifdef DEBUG_ACE
log_info("file_ace: Invalid block size %u\n", le16(h->size));
#endif
return ;
}
if(my_fseek(file_recovery->handle, -(off_t)sizeof(ace_header_t)+(off_t)4, SEEK_CUR)<0 ||
check_ace_crc(file_recovery->handle, le16(h->size), le16(h->crc16)) != 0)
{
file_recovery->offset_error=file_recovery->file_size;
file_recovery->file_size=0;
return ;
}
/* Add its header size */
file_recovery->file_size += (uint64_t)4 + le16(h->size); /* +2: CRC16, +2: size */
if(file_recovery->file_size >= 0x8000000000000000-0x100000000)
{
file_recovery->file_size=0;
return ;
}
/* If addsize flag, add complementary size */
if (le16(h->flags)&1)
{
file_recovery->file_size += le32(h->addsize);
if(my_fseek(file_recovery->handle, file_recovery->file_size, SEEK_SET)<0)
{
file_recovery->offset_error=file_recovery->file_size;
file_recovery->file_size=0;
return;
}
}
}
}
/*@
@ requires buffer_size >= sizeof(ace_header_t);
@ requires separation: \separated(&file_hint_ace, buffer+(..), file_recovery, file_recovery_new);
@ requires valid_header_check_param(buffer, buffer_size, safe_header_only, file_recovery, file_recovery_new);
@ terminates \true;
@ ensures valid_header_check_result(\result, file_recovery_new);
@ ensures (\result == 1) ==> file_recovery_new->file_size == 0;
@ ensures (\result == 1) ==> (file_recovery_new->time == 0);
@ ensures (\result == 1) ==> (file_recovery_new->calculated_file_size == 0);
@ ensures (\result == 1) ==> (file_recovery_new->extension == file_hint_ace.extension);
@ ensures (\result == 1) ==> (file_recovery_new->file_check == &file_check_ace);
@ assigns *file_recovery_new;
@*/
static int header_check_ace(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 ace_header_t *h=(const ace_header_t *)buffer;
if(le16(h->size) < 1+2 || h->type!=0)
return 0;
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_ace.extension;
file_recovery_new->min_filesize=
2 + /* CRC16 */
2 + /* Head size */
1 + /* Head type */
2 + /* Flags */
7 + /* Signature */
16; /* Minimal size for marker header */
file_recovery_new->file_check=&file_check_ace;
return 1;
}
static void register_header_check_ace(file_stat_t *file_stat)
{
static const unsigned char ace_header[7] = { '*','*','A','C','E','*','*'};
register_header_check(7, ace_header,sizeof(ace_header), &header_check_ace, file_stat);
}
#endif
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