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update entry of .got .dynamic

This commit is contained in:
pbonilla 2024-06-17 19:28:54 +02:00
parent 8571953eb3
commit 8c994bb196
3 changed files with 70 additions and 44 deletions
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2
includes/woody.h
View File

@ -40,6 +40,7 @@ typedef struct elf_content
int num_symbols;
Elf64_Shdr *text_section;
Elf64_Sym *symbols;
char *Sshstrtab;
} t_elf_content;
// utils.c
@ -47,6 +48,7 @@ void *fetch(char *file, unsigned long file_size, unsigned long offset_to_data, u
int ft_put_error(char *str);
char *get_string(char *str, char *end_file);
int get_symbols_count(int sh_size, int sh_entsize);
char *get_section_name(t_elf_content *woody, int section_index);
// woody.c
int prepare_injection(t_elf_content *woody);

6
srcs/utils.c
View File

@ -27,6 +27,12 @@ char *get_string(char *str, char *end_file)
return NULL;
}
char *get_section_name(t_elf_content *woody, int section_index)
{
unsigned int shstrtabndx = woody->Shdr[section_index].sh_name;
return get_string(&woody->Sshstrtab[shstrtabndx], woody->file + woody->file_size);
}
int ft_put_error(char *str)
{
ft_putstr_fd("Error: ", STDERR_FILENO);

106
srcs/woody.c
View File

@ -46,6 +46,63 @@ int get_load_segment(t_elf_content *woody, int start, bool executable)
void offset_sections(t_elf_content *woody, unsigned int from, unsigned int offset_ammount)
{
for (int i = 0; i < woody->Ehdr->e_shnum; i++)
{
if (woody->Shdr[i].sh_type == SHT_REL)
{
int num_entries = woody->Shdr[i].sh_size / woody->Shdr[i].sh_entsize;
Elf64_Rel *rel = (Elf64_Rel *)fetch(woody->file, woody->file_size, woody->Shdr[i].sh_offset, woody->Shdr[i].sh_size);
for (int j = 0; j < num_entries; j++)
{
rel[j].r_offset += offset_ammount;
printf(" Offset: 0x%lx, Info: 0x%lx, Type: %u, Symbol: %u\n",
(unsigned long)rel[j].r_offset, (unsigned long)rel[j].r_info,
(unsigned int)ELF64_R_TYPE(rel[j].r_info), (unsigned int)ELF64_R_SYM(rel[j].r_info));
}
}
else if (woody->Shdr[i].sh_type == SHT_RELA)
{
int num_entries = woody->Shdr[i].sh_size / woody->Shdr[i].sh_entsize;
Elf64_Rela *rela = (Elf64_Rela *)fetch(woody->file, woody->file_size, woody->Shdr[i].sh_offset , woody->Shdr[i].sh_size);
for (int j = 0; j < num_entries; j++)
{
rela[j].r_offset += offset_ammount;
if (rela[j].r_addend >= from)
rela[j].r_addend += offset_ammount;
// printf(" Offset: 0x%lx, Info: 0x%lx, Type: %u, Symbol: %u adden: 0x%lx\n",
// (unsigned long)rela[j].r_offset, (unsigned long)rela[j].r_info,
// (unsigned int)ELF64_R_TYPE(rela[j].r_info), (unsigned int)ELF64_R_SYM(rela[j].r_info), (unsigned long)rela[j].r_addend);
}
} else if (woody->Shdr[i].sh_type == SHT_DYNAMIC)
{
int num_dyn_entries = woody->Shdr[i].sh_size / woody->Shdr[i].sh_entsize;
Elf64_Dyn *dyn_entries = (Elf64_Dyn *)fetch(woody->file, woody->file_size, woody->Shdr[i].sh_offset , woody->Shdr[i].sh_size);
for (int j = 0; j < num_dyn_entries; j++)
{
// printf("dyn_entries[%d].d_tag = %lx ptr = %lx value = %lx\n",j, dyn_entries[j].d_tag, dyn_entries[j].d_un.d_ptr, dyn_entries[j].d_un.d_val);
if (dyn_entries[j].d_tag == DT_PLTGOT || dyn_entries[j].d_tag == DT_FINI || dyn_entries[j].d_tag == DT_INIT_ARRAY || dyn_entries[j].d_tag == DT_FINI_ARRAY)
{
dyn_entries[j].d_un.d_ptr += offset_ammount;
}
}
}
char *section_name = get_section_name(woody, i);
if (section_name && !ft_strcmp(".got", section_name))
{
int num_entries = woody->Shdr[i].sh_size / woody->Shdr[i].sh_entsize;
Elf64_Addr *got_entri = (Elf64_Addr *)fetch(woody->file, woody->file_size, woody->Shdr[i].sh_offset, woody->Shdr[i].sh_size);
for (int j = 0; j < num_entries; j++)
{
if (got_entri[j])
{
got_entri[j] += offset_ammount;
}
}
}
}
for (int i = 0; i < woody->Ehdr->e_phnum; i++)
{
if (woody->Phdr[i].p_offset >= from)
@ -70,38 +127,7 @@ void offset_sections(t_elf_content *woody, unsigned int from, unsigned int offse
woody->symbols[i].st_value += offset_ammount;
}
}
for (int i = 0; i < woody->Ehdr->e_shnum; i++) {
if (woody->Shdr[i].sh_type == SHT_REL)
{
printf("SHT_RE = %ld %ld\n", sizeof(Elf64_Rel), woody->Shdr[i].sh_entsize);
int num_entries = woody->Shdr[i].sh_size / woody->Shdr[i].sh_entsize;
for (int j = 0; j < num_entries; j++) {
Elf64_Rel *rel = (Elf64_Rel *)fetch(woody->file, woody->file_size, woody->Shdr[i].sh_offset + (j * woody->Shdr[i].sh_entsize), sizeof(Elf64_Rel));
rel->r_offset += offset_ammount;
// printf(" Offset: 0x%lx, Info: 0x%lx, Type: %u, Symbol: %u\n",
// (unsigned long)rel[j].r_offset, (unsigned long)rel[j].r_info,
// (unsigned int)ELF64_R_TYPE(rel[j].r_info), (unsigned int)ELF64_R_SYM(rel[j].r_info));
}
}
if (woody->Shdr[i].sh_type == SHT_RELA)
{
// printf("SHT_RELA = %ld %ld\n", sizeof(Elf64_Rela), woody->Shdr[i].sh_entsize);
int num_entries = woody->Shdr[i].sh_size / woody->Shdr[i].sh_entsize;
for (int j = 0; j < num_entries; j++) {
Elf64_Rela *rela = (Elf64_Rela *)fetch(woody->file, woody->file_size, woody->Shdr[i].sh_offset + (j * woody->Shdr[i].sh_entsize), sizeof(Elf64_Rela));
rela->r_offset += offset_ammount;
// printf(" Offset: 0x%lx, Info: 0x%lx, Type: %u, Symbol: %u, Addend: %ld\n",
// (unsigned long)rela[j].r_offset, (unsigned long)rela[j].r_info,
// (unsigned int)ELF64_R_TYPE(rela[j].r_info), (unsigned int)ELF64_R_SYM(rela[j].r_info),
// (long)rela[j].r_addend);
if (rela->r_addend >= from)
{
rela->r_addend += offset_ammount;
}
}
}
}
}
@ -185,18 +211,6 @@ void inject(t_elf_content *woody)
size_t code_cave_size = woody->Phdr[j].p_offset - (woody->Phdr[i].p_offset + woody->Phdr[i].p_filesz);
size_t payload_position = woody->Phdr[i].p_offset + woody->Phdr[i].p_filesz;
// printf("Load segment p_offset = %lx\n", woody->Phdr[i].p_offset);
// printf("Load segment p_filesz = %lx\n", woody->Phdr[i].p_filesz);
// printf("Load segment p_memsz = %lx\n", woody->Phdr[i].p_memsz);
// printf("Load segment p_offset = %lx\n", woody->Phdr[i + 1].p_offset);
// printf("Load segment p_filesz = %lx\n", woody->Phdr[i + 1].p_filesz);
// printf("Load segment p_memsz = %lx\n", woody->Phdr[i + 1].p_memsz);
// printf("text section sh_offset = %lx\n", woody->text_section->sh_offset);
// printf("text section sh_size = %lx\n", woody->text_section->sh_size);
// printf("text section sh_addr = %lx\n", woody->text_section->sh_addr);
if (code_cave_size < payload->len) // inverse here to test the other technique
{
printf("create code_Cave %ld\n", code_cave_size);
@ -208,7 +222,7 @@ void inject(t_elf_content *woody)
printf("%ld\n", woody->Phdr[i].p_align);
(void)payload_position;
insert_payload(woody, payload, payload_position, i);
//woody->Ehdr->e_entry = payload_position;
woody->Ehdr->e_entry = payload_position;
printf("New entry = %ld (%lx)\n", woody->Ehdr->e_entry, woody->Ehdr->e_entry);
printf("Load segment p_filesz = %lx\n", woody->Phdr[i].p_filesz);
printf("Load segment p_memsz = %lx\n", woody->Phdr[i].p_memsz);
@ -236,12 +250,16 @@ int get_elf_sections(t_elf_content *woody)
if (woody->Shdr[i].sh_type == SHT_PROGBITS && (woody->Shdr[i].sh_flags & SHF_EXECINSTR) && (woody->Shdr[i].sh_flags & SHF_ALLOC)) {
woody->text_section = fetch(woody->file, woody->file_size, woody->Ehdr->e_shoff + (i * sizeof(Elf64_Shdr)), sizeof(Elf64_Shdr));
}
}
if (woody->symbols_table == NULL || woody->text_section == NULL)
return EXIT_FAILURE; //Not sure about this
woody->symbols = (Elf64_Sym *)fetch(woody->file, woody->file_size, woody->symbols_table->sh_offset, sizeof(Elf64_Sym));
if (woody->symbols == NULL)
return EXIT_FAILURE;//Not sure about this
woody->Sshstrtab = (char *)fetch(woody->file, woody->file_size, woody->Shdr[woody->Ehdr->e_shstrndx].sh_offset, 0);
if (woody->Sshstrtab == NULL)
return EXIT_FAILURE; //Not sure about this
woody->num_symbols = get_symbols_count(woody->symbols_table->sh_size, woody->symbols_table->sh_entsize);
if (!fetch(woody->file, woody->file_size, woody->symbols_table->sh_offset + (sizeof(Elf64_Sym) * (woody->num_symbols)), 0))
return EXIT_FAILURE;