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woody-woodpacker
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fix trisomic jump

This commit is contained in:
pbonilla 2024-04-11 23:15:15 +02:00
parent fba60ca76e
commit 8a5bfae528
3 changed files with 18 additions and 8 deletions
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4
includes/woody.h
View File

@ -15,8 +15,8 @@
#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"
#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
{

2
print.s
View File

@ -18,5 +18,5 @@ _start:
pop rdi
pop rax
jmp 0x00000000
msg db "..WOODY..",10
section_sisze dq 0xcacacacacacacaca

20
srcs/woody.c
View File

@ -100,11 +100,21 @@ t_payload *get_payload()
int insert_payload(t_elf_content *woody, t_payload *payload, size_t payload_position)
{
char *ptr = ft_strnstr_nullterminated(payload->payload, JUMP, payload->len);
if (ptr)
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);
(void)ptr_section_size;
(void)ptr_text_section;
printf("text_section = %ld and size = %ld\n", woody->text_section->sh_offset, woody->text_section->sh_size);
if (ptr_jmp)
{
int32_t jmp_index = ptr - payload->payload;
int32_t jump_value = ((payload_position + payload->len) - woody->Ehdr->e_entry) * -1;
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_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));
ft_memcpy(woody->file + payload_position, payload->payload, payload->len);
@ -112,7 +122,7 @@ int insert_payload(t_elf_content *woody, t_payload *payload, size_t payload_posi
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)\n", jump_value, jump_value);
printf("Backwar d offset = %d (%x)(%x)\n", jump_value, jump_value, -jump_value);
return EXIT_SUCCESS;
}
return EXIT_FAILURE;