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woody-woodpacker
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fix: jump value hotfix, double injection OK

This commit is contained in:
gbrochar 2024-04-16 21:25:36 +02:00
parent ee6e39f716
commit 621a1ec641
3 changed files with 4 additions and 2 deletions
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1
gen_payload.sh Executable file
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@ -0,0 +1 @@
nasm -f elf64 -o print.o print.s && ld -o print print.o && nasm -f bin -o payload print.s && hexdump -v -e '"\\\x\" 1/1 "%02x"' payload

4
print.s
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@ -14,7 +14,7 @@ _start:
mov rdi, 1 mov rdi, 1
mov rdi, 1 mov rdi, 1
lea rsi, [rel msg] lea rsi, [rel msg]
mov rdx, 10 mov rdx, 14
mov rax, 1 mov rax, 1
syscall syscall
@ -24,4 +24,4 @@ _start:
pop rax pop rax
jmp 0x00000000 jmp 0x00000000
msg db "..WOODY..",10 msg db "....WOODY....",10

1
srcs/woody.c
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@ -100,6 +100,7 @@ int insert_payload(t_elf_content *woody, t_payload *payload, size_t payload_posi
{ {
int32_t jmp_index = ptr - payload->payload; int32_t jmp_index = ptr - payload->payload;
int32_t jump_value = ((payload_position + payload->len) - woody->Ehdr->e_entry) * -1; int32_t jump_value = ((payload_position + payload->len) - woody->Ehdr->e_entry) * -1;
jump_value += 14;
ft_memcpy(&payload->payload[jmp_index + 1], &jump_value, sizeof(jump_value)); ft_memcpy(&payload->payload[jmp_index + 1], &jump_value, sizeof(jump_value));
ft_memcpy(woody->file + payload_position, payload->payload, payload->len); ft_memcpy(woody->file + payload_position, payload->payload, payload->len);