/*

Executable memory regions demo / unit test

Copyright(c) 2015 Chris Eagle

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
version 2 as published by the Free Software Foundation.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

*/

#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <string.h>
#include <unistd.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include <unicorn/unicorn.h>

unsigned char PROGRAM[] =
   "\xeb\x45\x5e\x81\xe6\x00\xf0\xff\xff\x40\x40\x40\x40\x40\x40\x40"
   "\x40\x40\x40\x40\x40\x40\x40\x40\x40\x40\x40\x40\x40\x40\x40\x40"
   "\x40\x40\x40\x40\x40\x40\x40\x89\xf7\x81\xc7\x00\x00\x10\x00\xb9"
   "\x4c\x00\x00\x00\x81\xff\x00\x00\x40\x00\x75\x01\xf4\xf3\xa4\x81"
   "\xe7\x00\xf0\xff\xff\xff\xe7\xe8\xb6\xff\xff\xff";
// total size: 76 bytes

/*
bits 32

; assumes r-x section at 0x100000
; assumes rw- section at 0x200000
; assumes r-- section at 0x300000
; also needs an initialized stack

start:
   jmp bottom
top:
   pop esi
   and esi, ~0xfff
   times 30 inc eax
   mov edi, esi
   add edi, 0x100000
   mov ecx, end - start
   rep movsb
   and edi, ~0xfff
   cmp edi, 0x400000
   jnz next_block
   hlt
next_block:
   jmp edi
bottom:
   call top
end:
*/

int test_num  = 0;
uint32_t tests[] = {
   0x41414141,
   0x43434343,
   0x45454545
};

static int log_num = 1;

#define CODE_SECTION 0x100000
#define CODE_SIZE 0x1000

// callback for tracing instruction
static void hook_code(uch handle, uint64_t addr, uint32_t size, void *user_data)
{
   uint8_t opcode;
   if (uc_mem_read(handle, addr, &opcode, 1) != UC_ERR_OK) {
      printf("not ok %d - uc_mem_read fail during hook_code callback, addr: 0x%" PRIx64 "\n", log_num++, addr);
   }
//   printf("ok %d - uc_mem_read for opcode at address 0x%" PRIx64 "\n", log_num++, addr);
   switch (opcode) {
      case 0xf4:  //hlt
         printf("# Handling HLT\n");
         if (uc_emu_stop(handle) != UC_ERR_OK) {
            printf("not ok %d - uc_emu_stop fail during hook_code callback, addr: 0x%" PRIx64 "\n", log_num++, addr);
            _exit(-1);
         }
         else {
            printf("ok %d - hlt encountered, uc_emu_stop called\n", log_num++);
         }
         break;
      default:  //all others
//         printf("# Handling OTHER\n");
         break;
   }
}

// callback for tracing memory access (READ or WRITE)
static void hook_mem_write(uch handle, uc_mem_type type,
        uint64_t addr, int size, int64_t value, void *user_data)
{
   printf("# write to memory at 0x%"PRIx64 ", data size = %u, data value = 0x%"PRIx64 "\n", addr, size, value);
}

// callback for tracing invalid memory access (READ or WRITE)
static bool hook_mem_invalid(uch handle, uc_mem_type type,
        uint64_t addr, int size, int64_t value, void *user_data)
{
   switch(type) {
      default:
         printf("not ok %d - UC_HOOK_MEM_INVALID type: %d at 0x%" PRIx64 "\n", log_num++, type, addr);
         return false;
      case UC_MEM_NX:
         printf("# Fetch from non-executable memory at 0x%"PRIx64 "\n", addr);

         //make page executable
         if (uc_mem_protect(handle, addr & ~0xfffL, 0x1000, UC_PROT_READ | UC_PROT_EXEC) != UC_ERR_OK) {
            printf("not ok %d - uc_mem_protect fail for address: 0x%" PRIx64 "\n", log_num++, addr);
         }
         else {
            printf("ok %d - uc_mem_protect success at 0x%" PRIx64 "\n", log_num++, addr);
         }
         return true;
      case UC_MEM_WRITE_NW:
         printf("# write to non-writeable memory at 0x%"PRIx64 ", data size = %u, data value = 0x%"PRIx64 "\n", addr, size, value);

         if (uc_mem_protect(handle, addr & ~0xfffL, 0x1000, UC_PROT_READ | UC_PROT_WRITE) != UC_ERR_OK) {
            printf("not ok %d - uc_mem_protect fail during hook_mem_invalid callback, addr: 0x%" PRIx64 "\n", log_num++, addr);
         }
         else {
            printf("ok %d - uc_mem_protect success\n", log_num++);
         }
         return true;
   }
}

int main(int argc, char **argv, char **envp)
{
   uch handle, trace1, trace2;
   uc_err err;
   uint32_t esp, eip;
   int32_t buf1[1024], buf2[1024], readbuf[1024];
   int i;
   
   //don't really care about quality of randomness
   srand(time(NULL));
   for (i = 0; i < 1024; i++) {
      buf1[i] = rand();
      buf2[i] = rand();
   }

   printf("# Memory protect test\n");

   // Initialize emulator in X86-32bit mode
   err = uc_open(UC_ARCH_X86, UC_MODE_32, &handle);
   if (err) {
      printf("not ok %d - Failed on uc_open() with error returned: %u\n", log_num++, err);
      return 1;
   }
   else {
      printf("ok %d - uc_open() success\n", log_num++);
   }

   uc_mem_map(handle, 0x100000, 0x1000, UC_PROT_READ | UC_PROT_EXEC);
   uc_mem_map(handle, 0x1ff000, 0x2000, UC_PROT_READ | UC_PROT_WRITE);
   uc_mem_map(handle, 0x300000, 0x2000, UC_PROT_READ);
   uc_mem_map(handle, 0xf00000, 0x1000, UC_PROT_READ | UC_PROT_WRITE);

   esp = 0xf00000 + 0x1000;

   // Setup stack pointer
   if (uc_reg_write(handle, UC_X86_REG_ESP, &esp)) {
      printf("not ok %d - Failed to set esp. quit!\n", log_num++);
      return 2;
   }
   else {
      printf("ok %d - ESP set\n", log_num++);
   }

   // fill in sections that shouldn't get touched
   if (uc_mem_write(handle, 0x1ff000, (uint8_t*)buf1, 4096)) {
      printf("not ok %d - Failed to write random buffer 1 to memory, quit!\n", log_num++);
      return 3;
   }
   else {
      printf("ok %d - Random buffer 1 written to memory\n", log_num++);
   }

   if (uc_mem_write(handle, 0x301000, (uint8_t*)buf2, 4096)) {
      printf("not ok %d - Failed to write random buffer 2 to memory, quit!\n", log_num++);
      return 4;
   }
   else {
      printf("ok %d - Random buffer 2 written to memory\n", log_num++);
   }

   // write machine code to be emulated to memory
   if (uc_mem_write(handle, 0x100000, PROGRAM, sizeof(PROGRAM))) {
      printf("not ok %d - Failed to write emulation code to memory, quit!\n", log_num++);
      return 5;
   }
   else {
      printf("ok %d - Program written to memory\n", log_num++);
   }

   if (uc_hook_add(handle, &trace2, UC_HOOK_CODE, hook_code, NULL, 1, 0) != UC_ERR_OK) {
      printf("not ok %d - Failed to install UC_HOOK_CODE handler\n", log_num++);
      return 6;
   }
   else {
      printf("ok %d - UC_HOOK_CODE installed\n", log_num++);
   }

   // intercept memory write events
   if (uc_hook_add(handle, &trace1, UC_HOOK_MEM_WRITE, hook_mem_write, NULL) != UC_ERR_OK) {
      printf("not ok %d - Failed to install UC_HOOK_MEM_WRITE handler\n", log_num++);
      return 7;
   }
   else {
      printf("ok %d - UC_HOOK_MEM_WRITE installed\n", log_num++);
   }

   // intercept invalid memory events
   if (uc_hook_add(handle, &trace1, UC_HOOK_MEM_INVALID, hook_mem_invalid, NULL) != UC_ERR_OK) {
      printf("not ok %d - Failed to install UC_HOOK_MEM_INVALID handler\n", log_num++);
      return 8;
   }
   else {
      printf("ok %d - UC_HOOK_MEM_INVALID installed\n", log_num++);
   }

   // emulate machine code until told to stop by hook_code
   printf("# BEGIN execution\n");
   err = uc_emu_start(handle, 0x100000, 0x400000, 0, 0);
   if (err != UC_ERR_OK) {
      printf("not ok %d - Failure on uc_emu_start() with error %u:%s\n", log_num++, err, uc_strerror(err));
      return 9;
   }
   else {
      printf("ok %d - uc_emu_start complete\n", log_num++);
   }
   printf("# END execution\n");

   // get ending EIP
   if (uc_reg_read(handle, UC_X86_REG_EIP, &eip)) {
      printf("not ok %d - Failed to read eip.\n", log_num++);
   }
   else {
      printf("ok %d - Ending EIP 0x%x\n", log_num++, eip);
   }

   //make sure that random blocks didn't get nuked
   // fill in sections that shouldn't get touched
   if (uc_mem_read(handle, 0x1ff000, (uint8_t*)readbuf, 4096)) {
      printf("not ok %d - Failed to read random buffer 1 from memory\n", log_num++);
   }
   else {
      printf("ok %d - Random buffer 1 read from memory\n", log_num++);
      if (memcmp(buf1, readbuf, 4096)) {
         printf("not ok %d - Random buffer 1 contents are incorrect\n", log_num++);
      }
      else {
         printf("ok %d - Random buffer 1 contents are correct\n", log_num++);
      }
   }

   if (uc_mem_read(handle, 0x301000, (uint8_t*)readbuf, 4096)) {
      printf("not ok %d - Failed to read random buffer 2 from memory\n", log_num++);
   }
   else {
      printf("ok %d - Random buffer 2 read from memory\n", log_num++);
      if (memcmp(buf2, readbuf, 4096)) {
         printf("not ok %d - Random buffer 2 contents are incorrect\n", log_num++);
      }
      else {
         printf("ok %d - Random buffer 2 contents are correct\n", log_num++);
      }
   }

   if (uc_close(&handle) == UC_ERR_OK) {
      printf("ok %d - uc_close complete\n", log_num++);
   }
   else {
      printf("not ok %d - uc_close complete\n", log_num++);
   }

   return 0;
}