luisgulo/testdisk
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

src/file_elf.c: split header_check_elf() in 4 functions

Browse source
This commit is contained in:
Christophe Grenier 2021-02-19 17:21:36 +01:00
parent 9286b8b0dd
commit beb8d2f90c
1 changed files with 105 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

121
src/file_elf.c
View file

@ -32,6 +32,7 @@
#include "common.h" #include "common.h"
#include "filegen.h" #include "filegen.h"
/*@ requires \valid(file_stat); */
static void register_header_check_elf(file_stat_t *file_stat); static void register_header_check_elf(file_stat_t *file_stat);
const file_hint_t file_hint_elf= { const file_hint_t file_hint_elf= {
@ -118,28 +119,112 @@ typedef struct {
#define ELFDATA2LSB 1 /* 2's complement, little endian */ #define ELFDATA2LSB 1 /* 2's complement, little endian */
#define ELFDATA2MSB 2 /* 2's complement, big endian */ #define ELFDATA2MSB 2 /* 2's complement, big endian */
static int header_check_elf(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) /*@
@ requires buffer_size >= sizeof(Elf32_Ehdr);
@ 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_elf, buffer+(..), file_recovery, file_recovery_new);
@ assigns *file_recovery_new;
@ ensures \result == 0 || \result == 1;
@ ensures \result!=0 ==> valid_file_recovery(file_recovery_new);
@*/
static int header_check_elf32_lsb(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 Elf32_Ehdr *hdr32=(const Elf32_Ehdr *)buffer; const Elf32_Ehdr *hdr=(const Elf32_Ehdr *)buffer;
if(hdr32->e_ident[EI_DATA]!=ELFDATA2LSB && hdr32->e_ident[EI_DATA]!=ELFDATA2MSB) if(le32(hdr->e_version) != 1)
return 0;
if((hdr32->e_ident[EI_DATA]==ELFDATA2LSB ? le32(hdr32->e_version) : be32(hdr32->e_version)) != 1)
return 0; return 0;
/* http://en.wikipedia.org/wiki/Executable_and_Linkable_Format */ /* http://en.wikipedia.org/wiki/Executable_and_Linkable_Format */
reset_file_recovery(file_recovery_new); reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_elf.extension; file_recovery_new->extension=file_hint_elf.extension;
if(hdr32->e_ident[EI_CLASS]==ELFCLASS32)
{ {
const uint32_t tmp=(hdr32->e_ident[EI_DATA]==ELFDATA2LSB ? le32(hdr32->e_shoff) : be32(hdr32->e_shoff)); const uint32_t tmp=le32(hdr->e_shoff);
file_recovery_new->min_filesize=(hdr32->e_ident[EI_DATA]==ELFDATA2LSB ? le32(hdr32->e_phoff) : be32(hdr32->e_phoff)); file_recovery_new->min_filesize=le32(hdr->e_phoff);
if(file_recovery_new->min_filesize < tmp) if(file_recovery_new->min_filesize < tmp)
file_recovery_new->min_filesize=tmp; file_recovery_new->min_filesize=tmp;
} }
else return 1;
}
/*@
@ requires buffer_size >= sizeof(Elf32_Ehdr);
@ 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_elf, buffer+(..), file_recovery, file_recovery_new);
@ assigns *file_recovery_new;
@ ensures \result == 0 || \result == 1;
@ ensures \result!=0 ==> valid_file_recovery(file_recovery_new);
@*/
static int header_check_elf32_msb(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 Elf32_Ehdr *hdr=(const Elf32_Ehdr *)buffer;
if(be32(hdr->e_version) != 1)
return 0;
/* http://en.wikipedia.org/wiki/Executable_and_Linkable_Format */
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_elf.extension;
{ {
const Elf64_Ehdr *hdr64=(const Elf64_Ehdr *)buffer; const uint32_t tmp=be32(hdr->e_shoff);
const uint64_t tmp=(hdr64->e_ident[EI_DATA]==ELFDATA2LSB ? le64(hdr64->e_shoff) : be64(hdr64->e_shoff)); file_recovery_new->min_filesize=be32(hdr->e_phoff);
file_recovery_new->min_filesize=(hdr64->e_ident[EI_DATA]==ELFDATA2LSB ? le64(hdr64->e_phoff) : be64(hdr64->e_phoff)); if(file_recovery_new->min_filesize < tmp)
file_recovery_new->min_filesize=tmp;
}
return 1;
}
/*@
@ requires buffer_size >= sizeof(Elf64_Ehdr);
@ 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_elf, buffer+(..), file_recovery, file_recovery_new);
@ assigns *file_recovery_new;
@ ensures \result == 0 || \result == 1;
@ ensures \result!=0 ==> valid_file_recovery(file_recovery_new);
@*/
static int header_check_elf64_lsb(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 Elf64_Ehdr *hdr=(const Elf64_Ehdr *)buffer;
if(le32(hdr->e_version) != 1)
return 0;
/* http://en.wikipedia.org/wiki/Executable_and_Linkable_Format */
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_elf.extension;
{
const uint64_t tmp=le64(hdr->e_shoff);
file_recovery_new->min_filesize=le64(hdr->e_phoff);
if(file_recovery_new->min_filesize < tmp)
file_recovery_new->min_filesize=tmp;
}
return 1;
}
/*@
@ requires buffer_size >= sizeof(Elf64_Ehdr);
@ 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_elf, buffer+(..), file_recovery, file_recovery_new);
@ assigns *file_recovery_new;
@ ensures \result == 0 || \result == 1;
@ ensures \result!=0 ==> valid_file_recovery(file_recovery_new);
@*/
static int header_check_elf64_msb(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 Elf64_Ehdr *hdr=(const Elf64_Ehdr *)buffer;
if(be32(hdr->e_version) != 1)
return 0;
/* http://en.wikipedia.org/wiki/Executable_and_Linkable_Format */
reset_file_recovery(file_recovery_new);
file_recovery_new->extension=file_hint_elf.extension;
{
const uint64_t tmp=be64(hdr->e_shoff);
file_recovery_new->min_filesize=be64(hdr->e_phoff);
if(file_recovery_new->min_filesize < tmp) if(file_recovery_new->min_filesize < tmp)
file_recovery_new->min_filesize=tmp; file_recovery_new->min_filesize=tmp;
} }
@ -148,9 +233,13 @@ static int header_check_elf(const unsigned char *buffer, const unsigned int buff
static void register_header_check_elf(file_stat_t *file_stat) static void register_header_check_elf(file_stat_t *file_stat)
{ {
static const unsigned char elf_header16[5] = { 0x7f, 'E','L','F',0x01}; static const unsigned char elf_header32_lsb[6] = { 0x7f, 'E','L','F',0x01, ELFDATA2LSB};
static const unsigned char elf_header32[5] = { 0x7f, 'E','L','F',0x02}; static const unsigned char elf_header32_msb[6] = { 0x7f, 'E','L','F',0x01, ELFDATA2MSB};
register_header_check(0, elf_header16, sizeof(elf_header16), &header_check_elf, file_stat); static const unsigned char elf_header64_lsb[6] = { 0x7f, 'E','L','F',0x02, ELFDATA2LSB};
register_header_check(0, elf_header32, sizeof(elf_header32), &header_check_elf, file_stat); static const unsigned char elf_header64_msb[6] = { 0x7f, 'E','L','F',0x02, ELFDATA2MSB};
register_header_check(0, elf_header32_lsb, sizeof(elf_header32_lsb), &header_check_elf32_lsb, file_stat);
register_header_check(0, elf_header32_msb, sizeof(elf_header32_msb), &header_check_elf32_msb, file_stat);
register_header_check(0, elf_header64_lsb, sizeof(elf_header64_lsb), &header_check_elf64_lsb, file_stat);
register_header_check(0, elf_header64_msb, sizeof(elf_header64_msb), &header_check_elf64_msb, file_stat);
} }
#endif #endif