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PhotoRec: fix tar recovery

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Probably broken since commit 0dd2adf2da
This commit is contained in:
Christophe Grenier 2020-10-17 14:46:55 +02:00
parent b966e6cabd
commit 6f490ea9fa
5 changed files with 93 additions and 29 deletions
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89
src/file_tar.c
View file

@ -34,6 +34,8 @@
#include "file_tar.h"
static void register_header_check_tar(file_stat_t *file_stat);
static const unsigned char tar_header_gnu[6] = { 'u','s','t','a','r',0x00};
static const unsigned char tar_header_posix[8] = { 'u','s','t','a','r',' ',' ',0x00};
const file_hint_t file_hint_tar= {
.extension="tar",
@ -44,26 +46,63 @@ const file_hint_t file_hint_tar= {
.register_header_check=&register_header_check_tar
};
struct posix_header
{ /* byte offset */
char name[100]; /* 0 */
char mode[8]; /* 100 */
char uid[8]; /* 108 */
char gid[8]; /* 116 */
char size[12]; /* 124 */
char mtime[12]; /* 136 */
char chksum[8]; /* 148 */
char typeflag; /* 156 */
char linkname[100]; /* 157 */
char magic[6]; /* 257 */
char version[2]; /* 263 */
char uname[32]; /* 265 */
char gname[32]; /* 297 */
char devmajor[8]; /* 329 */
char devminor[8]; /* 337 */
char prefix[155]; /* 345 */
/* 500 */
};
/*@
@ requires \valid_read(h);
@ assigns \nothing;
@*/
static int is_valid_checksum_format(const struct tar_posix_header *h)
{
unsigned int i;
int space_allowed=1;
int all_null=1;
/* No checksum ? */
/*@
@ loop assigns i,all_null;
@*/
for(i=0; i<8; i++)
if(h->chksum[i]!=0)
all_null=0;
if(all_null!=0)
return 1;
/*
* Checksum should be stored as a six digit octal number with leading zeroes followed by a NUL and then a space.
* Various implementations do not adhere to this format, try to handle them
*/
/*@
@ loop assigns i,space_allowed;
@*/
for(i=0; i<6; i++)
{
if(h->chksum[i] >= '0' || h->chksum[i] <= '7')
{
space_allowed=0;
continue;
}
if(h->chksum[i] == ' ')
{
if(space_allowed == 0)
return 0;
}
else
return 0;
}
if(h->chksum[6] == 0 || h->chksum[7] == ' ')
return 1;
if((h->chksum[6] >= '0' || h->chksum[6] <= '7') && h->chksum[7] == ' ')
return 1;
return 0;
}
int is_valid_tar_header(const struct tar_posix_header *h)
{
/* Do not remove this check. */
if(memcmp(&h->magic,tar_header_gnu,sizeof(tar_header_gnu))!=0 &&
memcmp(&h->magic,tar_header_posix,sizeof(tar_header_posix))!=0)
return 0;
if(is_valid_checksum_format(h)==0)
return 0;
return 1;
}
/*@
@ requires buffer_size >= 512;
@ -74,10 +113,10 @@ struct posix_header
@ requires file_recovery_new->blocksize > 0;
@ requires separation: \separated(&file_hint_tar, buffer+(..), file_recovery, file_recovery_new);
@*/
int header_check_tar(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)
static int header_check_tar(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 posix_header *h=(const struct posix_header *)buffer;
if(!isspace(h->chksum[0]) && !((unsigned) (h->chksum[0]) - '0' <= 7))
const struct tar_posix_header *h=(const struct tar_posix_header *)buffer;
if(is_valid_tar_header(h)==0)
return 0;
if(file_recovery->file_stat!=NULL && file_recovery->file_stat->file_hint==&file_hint_tar)
{
@ -95,9 +134,9 @@ int header_check_tar(const unsigned char *buffer, const unsigned int buffer_size
@*/
static void register_header_check_tar(file_stat_t *file_stat)
{
static const unsigned char tar_header_gnu[6] = { 'u','s','t','a','r',0x00};
static const unsigned char tar_header_posix[8] = { 'u','s','t','a','r',' ',' ',0x00};
register_header_check(0x101, tar_header_gnu,sizeof(tar_header_gnu), &header_check_tar, file_stat);
#ifndef __FRAMAC__
register_header_check(0x101, tar_header_posix,sizeof(tar_header_posix), &header_check_tar, file_stat);
#endif
}
#endif

27
src/file_tar.h
View file

@ -25,7 +25,32 @@
extern "C" {
#endif
int header_check_tar(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);
struct tar_posix_header
{ /* byte offset */
char name[100]; /* 0 */
char mode[8]; /* 100 */
char uid[8]; /* 108 */
char gid[8]; /* 116 */
char size[12]; /* 124 */
char mtime[12]; /* 136 */
char chksum[8]; /* 148 */
char typeflag; /* 156 */
char linkname[100]; /* 157 */
char magic[6]; /* 257 */
char version[2]; /* 263 */
char uname[32]; /* 265 */
char gname[32]; /* 297 */
char devmajor[8]; /* 329 */
char devminor[8]; /* 337 */
char prefix[155]; /* 345 */
/* 500 */
};
/*@
@ requires \valid_read(h);
@ assigns \nothing;
@*/
int is_valid_tar_header(const struct tar_posix_header *h);
#ifdef __cplusplus
} /* closing brace for extern "C" */

2
src/phbs.c
View file

@ -103,7 +103,7 @@ pstatus_t photorec_find_blocksize(struct ph_param *params, const struct ph_optio
file_recovery_new.blocksize=blocksize;
file_recovery_new.location.start=offset;
if(file_recovery.file_stat!=NULL && file_recovery.file_stat->file_hint==&file_hint_tar &&
header_check_tar(buffer-0x200,0x200,0,&file_recovery,&file_recovery_new))
is_valid_tar_header((const struct tar_posix_header *)(buffer-0x200)))
{ /* Currently saving a tar, do not check the data for know header */
}
else

2
src/photorec_check_header.h
View file

@ -146,7 +146,7 @@ inline static pstatus_t photorec_check_header(file_recovery_t *file_recovery, st
file_recovery_new.blocksize=blocksize;
file_recovery_new.location.start=offset;
if(file_recovery->file_stat!=NULL && file_recovery->file_stat->file_hint==&file_hint_tar &&
header_check_tar(buffer-0x200,0x200, 0, file_recovery, &file_recovery_new))
is_valid_tar_header((const struct tar_posix_header *)(buffer-0x200)))
{ /* Currently saving a tar, do not check the data for know header */
if(options->verbose > 1)
{

2
src/qphbs.cpp
View file

@ -98,7 +98,7 @@ pstatus_t QPhotorec::photorec_find_blocksize(alloc_data_t *list_search_space)
{
file_recovery_t file_recovery_new;
if(file_recovery.file_stat!=NULL && file_recovery.file_stat->file_hint==&file_hint_tar &&
header_check_tar(buffer-0x200,0x200,0,&file_recovery,&file_recovery_new))
is_valid_tar_header((const struct tar_posix_header *)(buffer-0x200)))
{ /* Currently saving a tar, do not check the data for know header */
}
else