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425 lines
11 KiB

#include "Obfuscator.h"
//snake case is honestly so disgusting
void obf_one_time_please()
{
xed_tables_init();
}
bool obf_init_from_buffer(pobfuscator_t obf, void* buffer, int buffer_size)
{
obf->current_label_id = 0;
obf->machine_mode = XED_MACHINE_MODE_LONG_64;
obf->addr_width = XED_ADDRESS_WIDTH_64b;
unsigned long long off = 0;
obf->code_start = new code_link_t;
obf->code_end = obf->code_start;
obf->code_start->flags = 0;
obf->code_start->group = 0;
obf->code_start->label_name = "omegalawl";
obf->code_start->prev = obf->code_start->next = nullptr;
while (off < buffer_size)
{
pcode_link_t link = new code_link_t;
link->flags = 0;
link->group = 0;
xed_decoded_inst_zero(&link->instruction);
xed_decoded_inst_set_mode(&link->instruction, obf->machine_mode, obf->addr_width);
xed_error_enum_t err = xed_decode(&link->instruction, (unsigned char*)((unsigned char*)buffer + off), 15);
if (err != XED_ERROR_NONE)
{
printf("Failed decoding instruction at %llu with error \"%s\"(%d)", off, xed_error_enum_t2str(err), err);
return false;
}
unsigned int inst_len = xed_decoded_inst_get_length(&link->instruction);
link->raw_data_size = inst_len;
link->raw_data = (unsigned char*)malloc(inst_len);
if (!link->raw_data)
{
printf("outta memory son.\n");
return false;
}
memcpy(link->raw_data, ((unsigned char*)buffer + off), inst_len);
//filter out 8 byte wide jumps cuz they aint relative dawg and wont be showin up in my shellcod
xed_category_enum_t cat = xed_decoded_inst_get_category(&link->instruction);
if (cat == XED_CATEGORY_COND_BR || cat == XED_CATEGORY_UNCOND_BR)
{
unsigned int disp_width = xed_decoded_inst_get_branch_displacement_width(&link->instruction);
if (disp_width != 8)
{
link->flags |= CLFLAG_IS_REL_JUMP;
//int jump_delta = xed_decoded_inst_get_branch_displacement(&link->instruction);
//printf("Jump delta is %d\n", jump_delta);
}
}
link->prev = obf->code_end;
link->next = nullptr;
obf->code_end->next = link;
obf->code_end = link;
off += inst_len;
}
}
bool obf_create_groups(pobfuscator_t obf, int32_t group_size)
{
int cur_group_id = 0;
int cur_offset = 0;
//assign instructions to groups
for (pcode_link_t t = obf->code_start->next; t; t = t->next)
{
if (!(t->flags & CLFLAG_IS_LABEL))
{
if (!(t->flags & CLFLAG_IS_GAGET))
{
if (cur_offset + t->raw_data_size > group_size)
{
++cur_group_id;
cur_offset = 0;
}
}
cur_offset += t->raw_data_size;
t->group = cur_group_id;
}
}
//assign labels to their proper groups
for (pcode_link_t t = obf->code_start->next; t; t = t->next)
{
if (t->flags & CLFLAG_IS_LABEL)
{
pcode_link_t t2 = t;
while (t2 && (t2->flags & CLFLAG_IS_LABEL)) { t2 = t2->next; }
if (t2) t->group = t2->group;
}
}
//create group descriptors
obf->groups.clear();
pcode_link_t start = obf->code_start->next;
cur_offset = 0;
pcode_link_t prev_meme = nullptr;
for (pcode_link_t t = obf->code_start->next; t; t = t->next)
{
if (start->group != t->group)
{
obf->groups.emplace_back(0, start, t->prev, cur_offset);
cur_offset = 0;
start = t;
}
cur_offset += t->raw_data_size;
prev_meme = t;
}
if (!prev_meme)
return false;
obf->groups.emplace_back(0, start, prev_meme, cur_offset);
//append jumps to next group onto end
for (uint32_t i = 0; i < obf->groups.size() - 1; i++)
{
pcode_group_t cur_group = &obf->groups[i];
pcode_group_t next_group = &obf->groups[i+1];
//add jump gadget to end of current group
pcode_link_t gadget = new code_link_t;
gadget->flags = CLFLAG_IS_GAGET;
gadget->label_name = "";
gadget->raw_data = new unsigned char[6];
gadget->raw_data_size = 6;
gadget->group = i;
unsigned char gadget_data[] = { 0xFF, 0x25, 0x00, 0x00, 0x00, 0x00 };
memcpy(gadget->raw_data, gadget_data, 6);
pcode_link_t abs_addr = new code_link_t;
abs_addr->flags = (CLFLAG_IS_GAGET | CLFLAG_IS_ABS_ADDR);
abs_addr->label_name = std::string("Group") + std::to_string(i + 1);
abs_addr->raw_data = new unsigned char[8];
abs_addr->raw_data_size = 8;
abs_addr->group = i;
pcode_link_t real_next = cur_group->end->next;
cur_group->end->next = gadget;
gadget->next = abs_addr;
abs_addr->next = real_next;
real_next->prev = abs_addr;
abs_addr->prev = gadget;
gadget->prev = cur_group->end;
cur_group->end = abs_addr;
//add label to beginning of next group
pcode_link_t next_group_label = new code_link_t;
next_group_label->flags = CLFLAG_IS_LABEL;
next_group_label->label_name = std::string("Group") + std::to_string(i + 1);
next_group_label->group = i + 1;
pcode_link_t real_prev = next_group->start->prev;
next_group->start->prev = next_group_label;
real_prev->next = next_group_label;
next_group_label->next = next_group->start;
next_group_label->prev = real_prev;
next_group->start = next_group_label;
}
return true;
}
void obf_replace_rel_jmps(pobfuscator_t obf)
{ // original_jump -------------------------.
// jmp 0x0E(0xEB, 0x0E) ------------------ | -----.
// jmp qword ptr[rip] <----------------' |
// address here(8 bytes) |
// not taken branch code <-----------------------'
for (pcode_link_t t = obf->code_start->next; t;)
{
pcode_link_t real_next = t->next;
if (t->flags & CLFLAG_IS_REL_JUMP)
{
unsigned int jmp_delta_width = xed_decoded_inst_get_branch_displacement_width(&t->instruction);
unsigned int opcode_size = t->raw_data_size - jmp_delta_width;
switch (jmp_delta_width)
{
case 1:
*(char*)((unsigned char*)t->raw_data + opcode_size) = (char)2; break;
case 2:
*(short*)((unsigned char*)t->raw_data + opcode_size) = (short)2; break;
case 4:
*(int*)((unsigned char*)t->raw_data + opcode_size) = (int)2; break;
}
t->flags = CLFLAG_IS_GAGET;
pcode_link_t gadget = new code_link_t;
gadget->flags = CLFLAG_IS_GAGET;
gadget->label_name = "";
gadget->raw_data = new unsigned char[8];
gadget->raw_data_size = 8;
unsigned char gadget_data[] = { 0xEB, 0x0E, 0xFF, 0x25, 0x00, 0x00, 0x00, 0x00 };
memcpy(gadget->raw_data, gadget_data, 8);
pcode_link_t abs_addr = new code_link_t;
abs_addr->flags = (CLFLAG_IS_GAGET | CLFLAG_IS_ABS_ADDR);
abs_addr->label_name = t->label_name;
t->label_name = "";
abs_addr->raw_data = new unsigned char[8];
abs_addr->raw_data_size = 8;
t->next = gadget;
gadget->next = abs_addr;
abs_addr->next = real_next;
if (real_next) real_next->prev = abs_addr;
abs_addr->prev = gadget;
gadget->prev = t;
}
t = real_next;
}
}
bool obf_resolve_abs_addresses(pobfuscator_t obf)
{
for (pcode_link_t t = obf->code_start->next; t; t = t->next)
{
if (t->flags & CLFLAG_IS_ABS_ADDR)
{
pcode_link_t temp;
for (temp = t; temp && temp->prev; temp = temp->prev)
{
if (temp->flags & CLFLAG_IS_LABEL && temp->label_name == t->label_name)
{
goto have_label_found;
}
}
for (temp = t; temp && temp->next; temp = temp->next)
{
if (temp->flags & CLFLAG_IS_LABEL && temp->label_name == t->label_name)
{
goto have_label_found;
}
}
return false;
have_label_found:
uint64_t addr = obf->groups[temp->group].base_address;
for (pcode_link_t temp2 = obf->groups[temp->group].start; temp2 && temp2->group == temp->group; temp2 = temp2->next)
{
if (temp2 == temp)
{
break;
}
if (!(temp2->flags & CLFLAG_IS_LABEL))
{
addr += temp2->raw_data_size;
}
}
*(uint64_t*)((unsigned char*)t->raw_data) = addr;
}
}
return true;
}
size_t obf_get_group_size(pobfuscator_t obf, int group_id)
{
if (group_id < obf->groups.size())
return obf->groups[group_id].size_in_bytes;
}
void obf_copy_group_to_buffer(pobfuscator_t obf, void* buffer, int group_id)
{
}
bool obf_gen_all_labels(pobfuscator_t obf)
{
for (pcode_link_t t = obf->code_start->next; t; t = t->next)
{
if (t->flags & CLFLAG_IS_REL_JUMP)
{
int jump_delta = xed_decoded_inst_get_branch_displacement(&t->instruction);
if (!obf_gen_label(obf, t, jump_delta))
return false;
}
}
return true;
}
bool obf_gen_label(pobfuscator_t obf, pcode_link_t jmp, int32_t delta)
{
pcode_link_t temp;
//when going positive, counting starts at NEXT instruction(excluding size of jmp)
//when negative, counting INCLUDES the size of the jmp instructrion
if (delta > 0)
{
temp = jmp->next;
while (delta && temp)
{
delta -= temp->instruction._decoded_length;
//if (delta == 0) break;
temp = temp->next;
}
if (temp && temp->flags & CLFLAG_IS_LABEL)
{
jmp->label_name = temp->label_name;
return true;
}
}
else if (delta < 0)
{
temp = jmp;
while (temp)
{
delta += temp->instruction._decoded_length;
if (delta == 0) break;
temp = temp->prev;
}
if (temp && temp->prev && (temp->prev->flags & CLFLAG_IS_LABEL))
{
jmp->label_name = temp->prev->label_name;
return true;
}
}
else return false;
if (!temp)
return false;
//couldnt find label, adding new one
pcode_link_t new_label = new code_link_t;
new_label->flags = CLFLAG_IS_LABEL;
new_label->label_name = std::to_string(++obf->current_label_id);
jmp->label_name = new_label->label_name;
new_label->next = temp;
new_label->prev = temp->prev;
if (temp->prev)
temp->prev->next = new_label;
temp->prev = new_label;
return true;
}
#include <Windows.h>
void obf_dbg_print_code(pobfuscator_t obf)
{
HANDLE StdHandle = GetStdHandle(STD_OUTPUT_HANDLE);
if (!StdHandle)
return;
for (pcode_link_t t = obf->code_start->next; t; t = t->next)
{
if (t->group % 2)
SetConsoleTextAttribute(StdHandle, 12);
else
SetConsoleTextAttribute(StdHandle, 14);
if (t->flags & CLFLAG_IS_REL_JUMP)
{
printf("\tRel jmp to: %s\t\t", t->label_name.data());
}
else if (t->flags & CLFLAG_IS_LABEL)
{
//SetConsoleTextAttribute(StdHandle, 13);
printf("Label: %s \n", t->label_name.data());
}
else if (t->flags & CLFLAG_IS_ABS_ADDR)
{
printf("\tAbs jmp to: %s\t", t->label_name.data());
}
else
{
printf("\tInstruction: \t\t");
}
if (!(t->flags & CLFLAG_IS_LABEL))
{
obf_print_byte_array(t->raw_data, t->raw_data_size);
}
}
}
void obf_dbg_print_group(pobfuscator_t obf, int group_id)
{
if (group_id >= obf->groups.size())
return;
for (pcode_link_t t = obf->groups[group_id].start; t && t->group == group_id; t = t->next)
{
if (!(t->flags & CLFLAG_IS_LABEL))
{
obf_print_byte_array(t->raw_data, t->raw_data_size);
}
}
}
#include <iostream>
#include <iomanip>
void obf_print_byte_array(void* arr, unsigned int size)
{
unsigned char* b = (unsigned char*)arr;
for (int i = 0; i < size; i++)
{
std::cout << std::hex << std::setw(2) << std::setfill('0') << (int)b[i] << ' ';
}
std::cout << '\n';
return;
}