构建一个CPU模拟器
一、概述
本章节介绍的是windows环境下unicorn框架和capstone框架的使用。
二、工具
Visual stdio 2019
Cmake
Git
三、构建步骤
clone unicorn和capstone框架的源码。(注意clone的分支为最新版本，不是master)
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2git clone https://github.com/unicorn-engine/unicorn.git
git clone https://github.com/capstone-engine/capstone.git编译unicorn
使用git bash或者cmd进入unicorn目录，执行下面几条命令
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3mkdir build
cd build
cmake .. -G "Visual Studio 16 2019" -A "x64" -DCMAKE_BUILD_TYPE=Release接着在build目录下会生成一个unicorn.sln文件，使用visual stdio 2019打开，编译输出。在build目录下会生成unicorn.lib，在build/debug目录下会生成许多文件，只需要unicorn.dll即可
编译capstone
使用visual stdio 2019打开capstone/msvc目录下的capstone.sln文件，编译之后在capstone\msvc\x64\Debug目录下会生成capstone.dll和capstone.lib文件。
创建模拟器项目
使用visual stdio 2019创建一个新项目，然后导入上面两步骤生成的文件,再将上述框架中capstone和unicorn头文件(在include目录下)放入工程根目录中。
实现代码
下面是模拟x86架构64位程序代码片段，其中test_00007FF6B9541000.bin是.text段的内存dump文件，test_00000039AB52A000.bin为.stack段内存dump，test_00007FF6B9549000.bin为.rdata段内存dump，test_00007FF6B954C000.bin为.data段内存dump,test_00007FF6B9531000.bin为.textbss段内存dump。1
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csh g_x64_cs_handle = NULL;
cs_insn* g_x64_cs_insn = NULL;
size_t g_x64_cs_count = 0; // how many instruction that this capstone API disassembly successfully
cs_err g_x64_cs_err = CS_ERR_OK;
uc_engine* g_x64_uc = NULL;
uc_err g_x64_uc_err = UC_ERR_OK; // error number that unicorn emulate instruction
DWORD64 g_x64_instruction_count = 0;
REG_X86 g_x64_reg = { 0 }; // init register
//#define CODE "\x55\x48\x8b\x05\xb8\x13\x00\x00"
VOID x64_init_registers()
{
g_x64_reg.reg.r_rax = 0x00007FF6B9541230;
g_x64_reg.reg.r_rcx = 0x00000039AB77F000;
g_x64_reg.reg.r_rdx = 0x00007FF6B9541230;
g_x64_reg.reg.r_rbx = 0x0000000000000000;
g_x64_reg.reg.r_rsp = 0x00000039AB52FDB8;
g_x64_reg.reg.r_rbp = 0x0000000000000000l;
g_x64_reg.reg.r_rsi = 0x0000000000000000;
g_x64_reg.reg.r_rdi = 0x0000000000000000;
g_x64_reg.reg.r_rip = 0x00007FF6B9542330;
g_x64_reg.reg.r_rflag = 0x0000000000000246;
g_x64_reg.reg.r_r8 = 0x00000039AB77F000;
g_x64_reg.reg.r_r9 = 0x00007FF6B9541230;
g_x64_reg.reg.r_r10 = 0x00007FFFBD807C90;
g_x64_reg.reg.r_r11 = 0x0000000000000000l;
g_x64_reg.reg.r_r12 = 0x0000000000000000l;
g_x64_reg.reg.r_r13 = 0x0000000000000000l;
g_x64_reg.reg.r_r14 = 0x0000000000000000l;
g_x64_reg.reg.r_r15 = 0x0000000000000000l;
}
x64_FileInformation fileinfo[] =
{
// BaseAddress FileSize Path allocate buffer address
(PVOID)0x00007FF6B9541000 , 0x8000 , L".\\x64_binary\\test_00007FF6B9541000.bin" , NULL , //.text
(PVOID)0x00000039AB52A000 , 0x6000 , L".\\x64_binary\\test_00000039AB52A000.bin" , NULL , //.stack
(PVOID)0x00007FF6B9549000 , 0x3000 , L".\\x64_binary\\test_00007FF6B9549000.bin" , NULL , //.rdata
(PVOID)0x00007FF6B954C000 , 0x1000 , L".\\x64_binary\\test_00007FF6B954C000.bin" , NULL , //.data
(PVOID)0x00007FF6B9531000 , 0x10000 , L".\\x64_binary\\test_00007FF6B9531000.bin" , NULL , //.textbss
};
VOID x64_emulate()
{
g_x64_cs_err = cs_open(CS_ARCH_X86, CS_MODE_64, &g_x64_cs_handle);
g_x64_uc_err = uc_open(UC_ARCH_X86, UC_MODE_64, &g_x64_uc);
if (g_x64_cs_err || g_x64_uc_err)
{
printf("ERROR: Failed to initialize engine!\n");
return;
}
cs_option(g_x64_cs_handle, CS_OPT_DETAIL, CS_OPT_ON);
for (ULONG i = 0; i < sizeof(fileinfo) / sizeof(fileinfo[0]); i++)
{
FILE* pFile = NULL;
fileinfo[i].buffer = (PVOID)malloc(fileinfo[i].FileSize);
if (!fileinfo[i].buffer)
{
printf("Allocate mem fail!\n");
return;
}
pFile = _wfopen(fileinfo[i].FileName, L"rb");
if (!pFile)
{
printf("open file error code : <%d>\n", GetLastError());
return;
}
fread(fileinfo[i].buffer, fileinfo[i].FileSize, 1, pFile);
if (pFile)
fclose(pFile);
g_x64_uc_err = uc_mem_map(g_x64_uc, (DWORD64)fileinfo[i].BaseAddress, fileinfo[i].FileSize, UC_PROT_ALL);
if (g_x64_uc_err)
{
printf("uc mem map error!Error Code:<%d>\n", g_x64_uc_err);
return;
}
g_x64_uc_err = uc_mem_write(g_x64_uc, (DWORD64)fileinfo[i].BaseAddress, fileinfo[i].buffer, fileinfo[i].FileSize);
if (g_x64_uc_err)
{
printf("uc mem write error!Error Code:<%d>\n", g_x64_uc_err);
return;
}
}
x64_init_registers();
x64_write_uc_registers();
BYTE Code[32] = { 0 };
do
{
uc_mem_read(g_x64_uc, g_x64_reg.reg.r_rip, Code, sizeof(Code));
g_x64_cs_count = cs_disasm(g_x64_cs_handle, Code, sizeof(Code), g_x64_reg.reg.r_rip, 1, &g_x64_cs_insn);
if (!g_x64_cs_count)
break;
g_x64_uc_err = uc_emu_start(g_x64_uc, g_x64_reg.reg.r_rip, 0xffffffffffffffff, 0, 1);
x64_read_uc_registers();
x64_print_uc_registers();
x64_print_uc_stack(g_x64_reg.reg.r_rsp);
cs_free(g_x64_cs_insn, 1);
if (g_x64_uc_err)
{
printf("uc_emu_start error!Error Code:<%d>\n", g_x64_uc_err);
break;
}
g_x64_instruction_count++;
} while (g_x64_cs_count);
cs_close(&g_x64_cs_handle);
uc_close(g_x64_uc);
}
VOID x64_read_uc_registers()
{
uc_reg_read(g_x64_uc, UC_X86_REG_RAX, &g_x64_reg.reg.r_rax);
uc_reg_read(g_x64_uc, UC_X86_REG_RCX, &g_x64_reg.reg.r_rcx);
uc_reg_read(g_x64_uc, UC_X86_REG_RDX, &g_x64_reg.reg.r_rdx);
uc_reg_read(g_x64_uc, UC_X86_REG_RBX, &g_x64_reg.reg.r_rbx);
uc_reg_read(g_x64_uc, UC_X86_REG_RSP, &g_x64_reg.reg.r_rsp);
uc_reg_read(g_x64_uc, UC_X86_REG_RBP, &g_x64_reg.reg.r_rbp);
uc_reg_read(g_x64_uc, UC_X86_REG_RSI, &g_x64_reg.reg.r_rsi);
uc_reg_read(g_x64_uc, UC_X86_REG_RDI, &g_x64_reg.reg.r_rdi);
uc_reg_read(g_x64_uc, UC_X86_REG_RIP, &g_x64_reg.reg.r_rip);
uc_reg_read(g_x64_uc, UC_X86_REG_RFLAGS, &g_x64_reg.reg.r_rflag);
uc_reg_read(g_x64_uc, UC_X86_REG_R8, &g_x64_reg.reg.r_r8);
uc_reg_read(g_x64_uc, UC_X86_REG_R9, &g_x64_reg.reg.r_r9);
uc_reg_read(g_x64_uc, UC_X86_REG_R10, &g_x64_reg.reg.r_r10);
uc_reg_read(g_x64_uc, UC_X86_REG_R11, &g_x64_reg.reg.r_r11);
uc_reg_read(g_x64_uc, UC_X86_REG_R12, &g_x64_reg.reg.r_r12);
uc_reg_read(g_x64_uc, UC_X86_REG_R13, &g_x64_reg.reg.r_r13);
uc_reg_read(g_x64_uc, UC_X86_REG_R14, &g_x64_reg.reg.r_r14);
uc_reg_read(g_x64_uc, UC_X86_REG_R15, &g_x64_reg.reg.r_r15);
}
VOID x64_write_uc_registers()
{
uc_reg_write(g_x64_uc, UC_X86_REG_RAX, &g_x64_reg.reg.r_rax);
uc_reg_write(g_x64_uc, UC_X86_REG_RCX, &g_x64_reg.reg.r_rcx);
uc_reg_write(g_x64_uc, UC_X86_REG_RDX, &g_x64_reg.reg.r_rdx);
uc_reg_write(g_x64_uc, UC_X86_REG_RBX, &g_x64_reg.reg.r_rbx);
uc_reg_write(g_x64_uc, UC_X86_REG_RSP, &g_x64_reg.reg.r_rsp);
uc_reg_write(g_x64_uc, UC_X86_REG_RBP, &g_x64_reg.reg.r_rbp);
uc_reg_write(g_x64_uc, UC_X86_REG_RSI, &g_x64_reg.reg.r_rsi);
uc_reg_write(g_x64_uc, UC_X86_REG_RDI, &g_x64_reg.reg.r_rdi);
uc_reg_write(g_x64_uc, UC_X86_REG_RIP, &g_x64_reg.reg.r_rip);
uc_reg_write(g_x64_uc, UC_X86_REG_RFLAGS, &g_x64_reg.reg.r_rflag);
uc_reg_write(g_x64_uc, UC_X86_REG_R8, &g_x64_reg.reg.r_r8);
uc_reg_write(g_x64_uc, UC_X86_REG_R9, &g_x64_reg.reg.r_r9);
uc_reg_write(g_x64_uc, UC_X86_REG_R10, &g_x64_reg.reg.r_r10);
uc_reg_write(g_x64_uc, UC_X86_REG_R11, &g_x64_reg.reg.r_r11);
uc_reg_write(g_x64_uc, UC_X86_REG_R12, &g_x64_reg.reg.r_r12);
uc_reg_write(g_x64_uc, UC_X86_REG_R13, &g_x64_reg.reg.r_r13);
uc_reg_write(g_x64_uc, UC_X86_REG_R14, &g_x64_reg.reg.r_r14);
uc_reg_write(g_x64_uc, UC_X86_REG_R15, &g_x64_reg.reg.r_r15);
}
VOID x64_print_uc_registers()
{
printf("\n>--- --- --- %lld --- --- ---<\n", g_x64_instruction_count);
printf("%#16llx:\t%s\t%s\n",g_x64_cs_insn[0].address,g_x64_cs_insn[0].mnemonic,g_x64_cs_insn[0].op_str);
printf("rax=0x%16llx\n", g_x64_reg.reg.r_rax);
printf("rcx=0x%16llx\n", g_x64_reg.reg.r_rcx);
printf("rdx=0x%16llx\n", g_x64_reg.reg.r_rdx);
printf("rbx=0x%16llx\n", g_x64_reg.reg.r_rbx);
printf("rsp=0x%16llx\n", g_x64_reg.reg.r_rsp);
printf("rbp=0x%16llx\n", g_x64_reg.reg.r_rbp);
printf("rsi=0x%16llx\n", g_x64_reg.reg.r_rsi);
printf("rdi=0x%16llx\n", g_x64_reg.reg.r_rdi);
printf("rip=0x%16llx\n", g_x64_reg.reg.r_rip);
printf("rfl=0x%16llx\n", g_x64_reg.reg.r_rflag);
printf("r8 =0x%16llx\n", g_x64_reg.reg.r_r8);
printf("r9 =0x%16llx\n", g_x64_reg.reg.r_r9);
printf("r10=0x%16llx\n", g_x64_reg.reg.r_r10);
printf("r11=0x%16llx\n", g_x64_reg.reg.r_r11);
printf("r12=0x%16llx\n", g_x64_reg.reg.r_r12);
printf("r13=0x%16llx\n", g_x64_reg.reg.r_r13);
printf("r14=0x%16llx\n", g_x64_reg.reg.r_r14);
printf("r15=0x%16llx\n", g_x64_reg.reg.r_r15);
}
VOID x64_print_uc_stack(DWORD64 rsp)
{
DWORD64 val = 0;
for (ULONG i = 5; i > 0; i--)
{
uc_mem_read(g_x64_uc, (DWORD64)(rsp - i * 8), &val, sizeof(DWORD64));
printf("\t|%16llx|\n", val);
}
uc_mem_read(g_x64_uc, (DWORD64)rsp, &val, sizeof(DWORD64));
printf("===> |%16llx|\n", val);
for (ULONG i = 1; i < 5; i++)
{
uc_mem_read(g_x64_uc, (DWORD64)(rsp + i * 8), &val, sizeof(DWORD64));
printf("\t|%16llx|\n", val);
}
}上述代码是模拟x86_64程序，这个cpu模拟器框架还支持arm,aarch64，mips，risc-v,risc-v 64等汇编模拟。后续还会给出模拟risc-v 64程序的步骤。
学习过程中还有很多不足，还望朋友们指正！
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