142 lines
4.0 KiB
C
Executable File
142 lines
4.0 KiB
C
Executable File
#include <inttypes.h>
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#include <string.h>
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#include <unistd.h>
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#include <unicorn/unicorn.h>
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const uint8_t PROGRAM[] = "\xeb\x08\x58\xc7\x00\x78\x56\x34\x12\x90\xe8\xf3\xff\xff\xff";
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/*
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bits 32
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jmp short bottom
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top:
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pop eax
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mov dword [eax], 0x12345678
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nop
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bottom:
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call top
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*/
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// callback for tracing instruction
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static void hook_code(uch handle, uint64_t address, uint32_t size, void *user_data)
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{
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uint32_t esp;
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printf(">>> Tracing instruction at 0x%"PRIx64 ", instruction size = 0x%x\n", address, size);
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uc_reg_read(handle, UC_X86_REG_ESP, &esp);
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printf(">>> --- ESP is 0x%x\n", esp);
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}
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// callback for tracing memory access (READ or WRITE)
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static bool hook_mem_invalid(uch handle, uc_mem_type type,
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uint64_t address, int size, int64_t value, void *user_data)
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{
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uint32_t esp;
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uc_reg_read(handle, UC_X86_REG_ESP, &esp);
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switch(type) {
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default:
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// return false to indicate we want to stop emulation
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return false;
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case UC_MEM_WRITE:
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//if this is a push, esp has not been adjusted yet
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if (esp == (address + size)) {
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uint32_t upper;
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upper = (esp + 0xfff) & ~0xfff;
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printf(">>> Stack appears to be missing at 0x%"PRIx64 ", allocating now\n", address);
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// map this memory in with 2MB in size
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uc_mem_map(handle, upper - 0x8000, 0x8000);
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// return true to indicate we want to continue
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return true;
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}
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printf(">>> Missing memory is being WRITE at 0x%"PRIx64 ", data size = %u, data value = 0x%"PRIx64 "\n",
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address, size, value);
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return false;
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}
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}
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#define STACK 0x500000
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#define STACK_SIZE 0x5000
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int main(int argc, char **argv, char **envp) {
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uch handle, trace1, trace2;
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uc_err err;
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uint8_t bytes[8];
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uint32_t esp;
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int result;
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int map_stack = 0;
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if (argc == 2 && strcmp(argv[1], "--map-stack") == 0) {
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map_stack = 1;
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}
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printf("Memory mapping test\n");
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if (map_stack) {
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printf("Pre-mapping stack\n");
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}
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else {
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printf("Mapping stack on first invalid memory access\n");
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}
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// Initialize emulator in X86-32bit mode
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err = uc_open(UC_ARCH_X86, UC_MODE_32, &handle);
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if (err) {
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printf("Failed on uc_open() with error returned: %u\n", err);
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return 1;
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}
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uc_mem_map(handle, 0x100000, 0x1000);
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uc_mem_map(handle, 0x200000, 0x2000);
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uc_mem_map(handle, 0x300000, 0x3000);
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uc_mem_map_ex(handle, 0x400000, 0x4000, UC_PROT_READ | UC_PROT_EXEC);
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if (map_stack) {
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uc_mem_map_ex(handle, STACK, STACK_SIZE, UC_PROT_READ | UC_PROT_WRITE);
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}
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esp = STACK + STACK_SIZE;
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uc_reg_write(handle, UC_X86_REG_ESP, &esp);
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// write machine code to be emulated to memory
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if (uc_mem_write(handle, 0x400000, PROGRAM, sizeof(PROGRAM))) {
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printf("Failed to write emulation code to memory, quit!\n");
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return 2;
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}
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else {
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printf("Allowed to write to read only memory via uc_mem_write\n");
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}
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//uc_hook_add(handle, &trace2, UC_HOOK_CODE, hook_code, NULL, (uint64_t)0x400000, (uint64_t)0x400fff);
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// intercept invalid memory events
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uc_hook_add(handle, &trace1, UC_HOOK_MEM_INVALID, hook_mem_invalid, NULL);
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// emulate machine code in infinite time
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printf("BEGIN execution\n");
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err = uc_emu_start(handle, 0x400000, 0x400000 + sizeof(PROGRAM), 0, 5);
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if (err) {
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printf("Failed on uc_emu_start() with error returned %u: %s\n",
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err, uc_strerror(err));
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return 3;
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}
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printf("END execution\n");
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printf("Verifying content at bottom of stack is readable and correct\n");
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if (!uc_mem_read(handle, esp - 4, bytes, 4)) {
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printf(">>> Read 4 bytes from [0x%x] = 0x%x\n", (uint32_t)(esp - 4), *(uint32_t*) bytes);
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}
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else {
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printf(">>> Failed to read 4 bytes from [0x%x]\n", (uint32_t)(esp - 4));
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return 4;
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}
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uc_close(&handle);
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return 0;
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}
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