From 6fe049bbda7626a689eccbbd250db117fe50b89b Mon Sep 17 00:00:00 2001
From: gbrochar <gaetanbrochard@protonmail.com>
Date: Mon, 20 Jan 2025 12:28:27 +0100
Subject: [PATCH] fix: no-PIE ELF

---
 src/woody_woodpacker.c | 23 +++++++++++++++++++++--
 1 file changed, 21 insertions(+), 2 deletions(-)

diff --git a/src/woody_woodpacker.c b/src/woody_woodpacker.c
index 6e9ebca..a7cd6ff 100644
--- a/src/woody_woodpacker.c
+++ b/src/woody_woodpacker.c
@@ -32,6 +32,20 @@ int pack_elf32(t_map file) {
 	return wdy_error("ELF needs to be in 64 bits format");
 }
 
+
+int get_first_load_segment64(
+		Elf64_Ehdr elf_header,
+		Elf64_Phdr *program_headers,
+		Elf64_Phdr **first_load_segment) {
+	for (int i = 0; i < elf_header.e_phnum; i++) {
+		Elf64_Phdr *p_hdr = &program_headers[i];
+		if (p_hdr->p_type == PT_LOAD) {
+			*first_load_segment = p_hdr;
+			return RET_OK;
+		}
+	}
+	return RET_ERR;
+}
 int get_load_segment64(
 		Elf64_Ehdr elf_header,
 		Elf64_Phdr *program_headers,
@@ -91,6 +105,11 @@ int pack_elf64(t_map file) {
 		return wdy_error("cannot fetch program headers table");
 	}
 
+	Elf64_Phdr *first_load_segment;
+	if (get_first_load_segment64(*elf_header, program_headers, &first_load_segment) == RET_ERR) {
+		return wdy_error("cannot get first load segment");
+	}
+
 	Elf64_Phdr *load_segment;
 	if (get_load_segment64(*elf_header, program_headers, &load_segment) == RET_ERR) {
 		return wdy_error("cannot get load segment");
@@ -128,7 +147,7 @@ int pack_elf64(t_map file) {
 	// jump_offset is the index of jump from code cave start
 	// 4 because jump has a 4 byte operand)
 	size_t code_cave_start = code_cave.data - file.data;
-	int jump_value = elf_header->e_entry - code_cave_start - payload.jump_offset - 4;
+	int jump_value = elf_header->e_entry - first_load_segment->p_paddr - code_cave_start - payload.jump_offset - 4;
 	ft_memcpy(payload.data + payload.jump_offset, &jump_value, sizeof(jump_value));
 
 	if (payload.encrypt != NULL) {
@@ -143,7 +162,7 @@ int pack_elf64(t_map file) {
 		payload.encrypt(file, key, *load_segment);
 		free(key);
 	}
-	elf_header->e_entry = code_cave.data - file.data;
+	elf_header->e_entry = code_cave.data - file.data + first_load_segment->p_paddr;
 	load_segment->p_filesz += payload.len;
 	load_segment->p_memsz += payload.len;
 	load_segment->p_flags |= PF_W | PF_R;