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No commits in common. "d1c86e7165b04e01efe13e93761502769b9cdfec" and "fa004f3a6a4ec91db744723207de03167f050a9e" have entirely different histories.

8 changed files with 80 additions and 107 deletions

3
.gitignore vendored
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@ -2,6 +2,3 @@
*.a
woody_woodpacker
woody
asm
payload
print

8
.vscode/settings.json vendored Normal file
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@ -0,0 +1,8 @@
{
"files.associations": {
"stdio.h": "c",
"mman.h": "c",
"stdint.h": "c",
"compare": "c"
}
}

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@ -15,8 +15,6 @@
#include <stdint.h>
#define JUMP "\xe9"
#define TEXT_OFFSET "\xba\xba\xba\xba\xba\xba\xba\xba"
#define SECTION_SIZE "\xca\xca\xca\xca\xca\xca\xca\xca"
typedef struct payload
{
@ -24,7 +22,7 @@ typedef struct payload
size_t len;
} t_payload;
typedef struct elf_content
typedef struct efl_content
{
long unsigned int file_size;
char *file_path;
@ -32,18 +30,15 @@ typedef struct elf_content
Elf64_Ehdr *Ehdr;
Elf64_Phdr *Phdr;
Elf64_Shdr *Shdr;
Elf64_Shdr *text_section;
char *extra_data;
} t_elf_content;
} t_efl_content;
// utils.c
void *fetch(char *file, unsigned long file_size, unsigned long offset_to_data, unsigned long supposed_data_size);
int ft_put_error(char *str);
char *get_string(char *str, char *end_file);
int get_symbols_count(int sh_size, int sh_entsize);
// woody.c
int prepare_injection(t_elf_content *woody);
int prepare_injection(t_efl_content *woody);
// encrypt.c
void encrypt(char *file, unsigned long int offset, unsigned long int size);

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@ -7,16 +7,21 @@ _start:
push rsi
push rdx
mov rdi, 1
mov rdi, 1
mov rdi, 1
mov rdi, 1
mov rdi, 1
mov rdi, 1
lea rsi, [rel msg]
mov rdx, 10
mov rax, 1
syscall
pop rdx
pop rsi
pop rdi
pop rax
jmp 0x00000000
msg db "..WOODY..",10
text_section dq 0xbabababababababa
section_sisze dq 0xcacacacacacacaca

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@ -5,7 +5,7 @@ void encrypt(char *file, unsigned long int offset, unsigned long int size)
size_t i = 0;
while (i < size)
{
file[offset + i] = file[offset + i] + 1;
file[offset + i] = 0;
++i;
}
}

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@ -1,6 +1,6 @@
#include "../includes/woody.h"
int get_elf_file(t_elf_content *woody)
int get_elf_file(t_efl_content *woody)
{
int fd;
off_t off;
@ -32,7 +32,7 @@ int get_elf_file(t_elf_content *woody)
int main(int ac, char **av)
{
t_elf_content woody;
t_efl_content woody;
if (ac != 2)
{
return ft_put_error("Woody_woodpacker take 1 argument\n");

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@ -7,26 +7,6 @@ void *fetch(char *file, unsigned long file_size, unsigned long offset_to_data, u
return NULL;
}
int get_symbols_count(int sh_size, int sh_entsize)
{
if (sh_size <= 0 || sh_entsize <= 0)
return 0;
return (sh_size / sh_entsize);
}
char *get_string(char *str, char *end_file)
{
char *search_end = str;
while (search_end < end_file)
{
if (*search_end == 0)
return str;
++search_end;
}
return NULL;
}
int ft_put_error(char *str)
{
ft_putstr_fd("Error: ", STDERR_FILENO);

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@ -27,7 +27,7 @@ int save_elf(char *path, char *file, unsigned long int size)
return EXIT_SUCCESS;
}
int get_load_segment(t_elf_content *woody, int start, bool executable)
int get_load_segment(t_efl_content *woody, int start, bool executable)
{
for (int i = start; i < woody->Ehdr->e_phnum; i++)
{
@ -45,7 +45,7 @@ int get_load_segment(t_elf_content *woody, int start, bool executable)
return -1;
}
void offset_sections(t_elf_content *woody, unsigned int from, unsigned int offset_ammount)
void offset_sections(t_efl_content *woody, unsigned int from, unsigned int offset_ammount)
{
for (int i = 0; i < woody->Ehdr->e_phnum; i++)
{
@ -59,7 +59,7 @@ void offset_sections(t_elf_content *woody, unsigned int from, unsigned int offse
}
}
size_t create_codecave(t_elf_content *woody, Elf64_Phdr *load_segment, t_payload *payload)
size_t create_codecave(t_efl_content *woody, Elf64_Phdr *load_segment, t_payload *payload)
{
const unsigned int page_size = 4096; // getpagesize(); not authorized
unsigned int padding_size = ((payload->len / page_size) + 1) * page_size;
@ -87,55 +87,37 @@ t_payload *get_payload()
return NULL;
char buffer[1024];
int fd = open("payload", O_RDONLY);
if (fd == -1) {
perror("error opening payload");
free(payload);
exit(1);
}
payload->len = read(fd, buffer, 1024);
payload->payload = malloc(sizeof(char) * payload->len);
ft_memcpy(payload->payload, buffer, payload->len);
return payload;
}
int insert_payload(t_elf_content *woody, t_payload *payload, size_t payload_position)
int insert_payload(t_efl_content *woody, t_payload *payload, size_t payload_position)
{
char *ptr_jmp = ft_strnstr_nullterminated(payload->payload, JUMP, payload->len);
char *ptr_text_section = ft_strnstr_nullterminated(payload->payload, TEXT_OFFSET, payload->len);
char *ptr_section_size = ft_strnstr_nullterminated(payload->payload, SECTION_SIZE, payload->len);
if (ptr_jmp && ptr_text_section && ptr_section_size)
char *ptr = ft_strnstr_nullterminated(payload->payload, JUMP, payload->len);
if (ptr)
{
printf("test a jumo = %ld\n", ptr_jmp - payload->payload);
printf("test a jumo = %ld\n", ptr_jmp - payload->payload + sizeof(JUMP));
printf("jump base = %ld\n", payload->len);
printf("the jump = %ld\n", payload->len - 16);
int32_t jmp_index = ptr - payload->payload;
int32_t jump_value = ((payload_position + payload->len) - woody->Ehdr->e_entry) * -1;
int32_t jmp_index = ptr_jmp - payload->payload;
int32_t jump_value = (payload_position - woody->Ehdr->e_entry + jmp_index - 1) * -1;
ft_memcpy(&payload->payload[jmp_index + 1], &jump_value, sizeof(jump_value));
int64_t text_index = ptr_text_section - payload->payload;
int64_t text_value = (payload_position - woody->text_section->sh_offset + text_index - 1) * -1;
text_value = 0;
ft_memcpy(&payload->payload[text_index], &text_value, sizeof(text_value));
int64_t section_index = ptr_section_size - payload->payload;
int64_t section_value = (payload_position - woody->text_section->sh_size + section_index - 1) * -1;
ft_memcpy(&payload->payload[section_index], &section_value, sizeof(section_value));
ft_memcpy(woody->file + payload_position, payload->payload, payload->len);
printf("Old entry : %ld (%lx)\n", woody->Ehdr->e_entry, woody->Ehdr->e_entry);
printf("Code cave start = %ld (%lx)\n", payload_position, payload_position);
printf("Payload size = %ld (%lx)\n", payload->len, payload->len);
printf("Backwar d offset = %d (%x)(%x)\n", jump_value, jump_value, -jump_value);
printf("Backwar d offset = %d (%x)\n", jump_value, jump_value);
return EXIT_SUCCESS;
}
return EXIT_FAILURE;
}
void inject(t_elf_content *woody)
void inject(t_efl_content *woody)
{
t_payload *payload = get_payload();
int i = get_load_segment(woody, 0, true);
int j = get_load_segment(woody, i + 1, false);
@ -143,6 +125,7 @@ void inject(t_elf_content *woody)
size_t payload_position;
printf("load position = : %ld (%lx)\n", woody->Phdr[i].p_offset, woody->Phdr[i].p_offset);
printf("load size = : %ld (%lx)\n", woody->Phdr[i].p_filesz, woody->Phdr[i].p_filesz);
if (code_cave_size > payload->len) // inverse here to test the other technique
{
payload_position = woody->Phdr[i].p_offset + woody->Phdr[i].p_memsz;
@ -157,20 +140,11 @@ void inject(t_elf_content *woody)
woody->Ehdr->e_entry = payload_position;
woody->Phdr[i].p_filesz += payload->len;
woody->Phdr[i].p_memsz += payload->len;
woody->Phdr[i].p_flags = PF_X | PF_W | PF_R;
woody->text_section->sh_size += payload->len;
printf("New entry = %ld (%lx)\n", woody->Ehdr->e_entry, woody->Ehdr->e_entry);
}
int is_special_section_indice(uint16_t section_index) {
return (section_index == SHN_LOPROC || section_index == SHN_BEFORE ||
section_index == SHN_AFTER || section_index == SHN_HIPROC ||
section_index == SHN_LOOS || section_index == SHN_HIOS ||
section_index == SHN_ABS || section_index == SHN_COMMON ||
section_index == SHN_XINDEX || section_index == SHN_HIRESERVE);
}
int get_elf_sections(t_elf_content *woody)
int get_elf_sections(t_efl_content *woody)
{
woody->Ehdr = (Elf64_Ehdr *)fetch(woody->file, woody->file_size, 0, sizeof(Elf64_Ehdr));
if (!woody->Ehdr || !elf_magic_numbers(woody->file) || woody->Ehdr->e_ident[EI_CLASS] != ELFCLASS64)
@ -181,44 +155,58 @@ int get_elf_sections(t_elf_content *woody)
woody->Phdr = (Elf64_Phdr *)fetch(woody->file, woody->file_size, woody->Ehdr->e_phoff, sizeof(Elf64_Phdr));
woody->Shdr = (Elf64_Shdr *)fetch(woody->file, woody->file_size, woody->Ehdr->e_shoff, sizeof(Elf64_Shdr));
if (!woody->Shdr|| !fetch(woody->file, woody->file_size, woody->Ehdr->e_shoff, woody->Ehdr->e_shnum * sizeof(Elf64_Shdr)))
return EXIT_FAILURE;
if (woody->Shdr == NULL || !fetch(woody->file, woody->file_size, woody->Ehdr->e_shoff, woody->Ehdr->e_shnum * sizeof(Elf64_Shdr)))
{
return ft_put_error("Corrupted file");
}
// Elf64_Shdr *symbols_table = NULL;
// for (int i = 0; i < woody->Ehdr->e_shnum; i++) {
// if (Shdr[i].sh_type == SHT_SYMTAB) {
// symbols_table = fetch(woody->file, woody->file_size, woody->Ehdr->e_shoff + (i * sizeof(Elf64_Shdr)), sizeof(Elf64_Shdr));
// }
// }
// if (symbols_table == NULL)
// return ft_put_error("No symbols");
// if (!fetch(woody->file, woody->file_size, woody->Ehdr->e_shoff + (woody->Ehdr->e_shstrndx * sizeof(Elf64_Shdr)), sizeof(Elf64_Shdr)))
// return ft_put_error("Corrupted file");
// char *Sshstrtab = (char *)fetch(woody->file, woody->file_size, Shdr[woody->Ehdr->e_shstrndx].sh_offset, 0);
// if (Sshstrtab == NULL)
// return ft_put_error("Corrupted file");
// Elf64_Shdr *strtab_header = (Elf64_Shdr *)fetch(woody->file, woody->file_size, woody->Ehdr->e_shoff + (symbols_table->sh_link * woody->Ehdr->e_shentsize), sizeof(Elf64_Shdr));
// if (!strtab_header)
// return ft_put_error("Corrupted file");
// char *strtab = fetch(woody->file, woody->file_size, strtab_header->sh_offset, 0);
// if (strtab == NULL)
// return ft_put_error("Corrupted file");
// Elf64_Sym *symbols = (Elf64_Sym *)fetch(woody->file, woody->file_size, symbols_table->sh_offset, sizeof(Elf64_Sym));
// if (symbols == NULL)
// return ft_put_error("Corrupted file");
if (!fetch(woody->file, woody->file_size, woody->Ehdr->e_shoff + (woody->Ehdr->e_shstrndx * sizeof(Elf64_Shdr)), sizeof(Elf64_Shdr)))
{
return EXIT_FAILURE;
}
char *Sshstrtab = (char *)fetch(woody->file, woody->file_size, woody->Shdr[woody->Ehdr->e_shstrndx].sh_offset, 0);
if (Sshstrtab == NULL)
{
return EXIT_FAILURE;
}
for (int j = 0; j < woody->Ehdr->e_shnum;j++)
{
if (woody->Shdr[j].sh_name > woody->Shdr[woody->Ehdr->e_shstrndx].sh_size) return EXIT_FAILURE;
if (woody->Shdr[j].sh_type == SHT_PROGBITS && woody->Shdr[j].sh_flags & SHF_EXECINSTR &&
woody->Shdr[j].sh_flags & SHF_ALLOC &&
Sshstrtab + woody->Shdr[j].sh_name < (char *)woody->file + woody->file_size &&
!ft_strncmp(".text\0", Sshstrtab + woody->Shdr[j].sh_name, 6))
{
woody->text_section = &woody->Shdr[j];
break;
}
}
return EXIT_SUCCESS;
}
int prepare_injection(t_elf_content *woody)
int prepare_injection(t_efl_content *woody)
{
int elf_statut = get_elf_sections(woody);
if (elf_statut)
return elf_statut;
inject(woody);
// encrypt(woody->file, woody->text_section->sh_offset, woody->text_section->sh_size);
char *woody_file;
if (!(woody_file = malloc(woody->file_size)))
return ft_put_error("Allocation error");
ft_memcpy(woody_file, woody->file, woody->file_size);
// encrypt(woody_file, strtab_header->sh_offset , strtab_header->sh_size);
munmap(woody_file, woody->file_size);
save_elf("woody", woody_file, woody->file_size);
free(woody_file);