unicorn/samples/sample_arm.c

/* Unicorn Emulator Engine */
/* By Nguyen Anh Quynh, 2015 */

/* Sample code to demonstrate how to emulate ARM code */

#include <unicorn/unicorn.h>
#include <string.h>

// code to be emulated
// #define ARM_CODE "\x37\x00\xa0\xe3" // mov r0, #0x37
#define ARM_CODE "\x00\xf0\x20\xe3" // nop
// #define ARM_CODE "\x37\x00\xa0\xe3\x03\x10\x42\xe0" // mov r0, #0x37; sub r1,
// r2, r3
#define THUMB_CODE "\x83\xb0" // sub    sp, #0xc

#define ARM_THUM_COND_CODE                                                     \
    "\x9a\x42\x14\xbf\x68\x22\x4d\x22" // 'cmp r2, r3\nit ne\nmov r2, #0x68\nmov
                                       // r2, #0x4d'

// code to be emulated
#define ARM_CODE_EB                                                            \
    "\xe3\xa0\x00\x37\xe0\x42\x10\x03" // mov r0, #0x37; sub r1, r2, r3
#define THUMB_CODE_EB "\xb0\x83"       // sub    sp, #0xc
// memory address where emulation starts
#define ADDRESS 0x10000

static void hook_block(uc_engine *uc, uint64_t address, uint32_t size,
                       void *user_data)
{
    printf(">>> Tracing basic block at 0x%" PRIx64 ", block size = 0x%x\n",
           address, size);
}

static void hook_code(uc_engine *uc, uint64_t address, uint32_t size,
                      void *user_data)
{
    printf(">>> Tracing instruction at 0x%" PRIx64
           ", instruction size = 0x%x\n",
           address, size);
}

static void test_arm(void)
{
    uc_engine *uc;
    uc_err err;
    uc_hook trace1, trace2;

    int r0 = 0x1234; // R0 register
    int r2 = 0x6789; // R1 register
    int r3 = 0x3333; // R2 register
    int r1;          // R1 register

    printf("Emulate ARM code\n");

    // Initialize emulator in ARM mode
    err = uc_open(UC_ARCH_ARM, UC_MODE_ARM, &uc);
    if (err) {
        printf("Failed on uc_open() with error returned: %u (%s)\n", err,
               uc_strerror(err));
        return;
    }

    // map 2MB memory for this emulation
    uc_mem_map(uc, ADDRESS, 2 * 1024 * 1024, UC_PROT_ALL);

    // write machine code to be emulated to memory
    uc_mem_write(uc, ADDRESS, ARM_CODE, sizeof(ARM_CODE) - 1);

    // initialize machine registers
    uc_reg_write(uc, UC_ARM_REG_R0, &r0);
    uc_reg_write(uc, UC_ARM_REG_R2, &r2);
    uc_reg_write(uc, UC_ARM_REG_R3, &r3);

    // tracing all basic blocks with customized callback
    uc_hook_add(uc, &trace1, UC_HOOK_BLOCK, hook_block, NULL, 1, 0);

    // tracing one instruction at ADDRESS with customized callback
    uc_hook_add(uc, &trace2, UC_HOOK_CODE, hook_code, NULL, ADDRESS, ADDRESS);

    // emulate machine code in infinite time (last param = 0), or when
    // finishing all the code.
    err = uc_emu_start(uc, ADDRESS, ADDRESS + sizeof(ARM_CODE) - 1, 0, 0);
    if (err) {
        printf("Failed on uc_emu_start() with error returned: %u\n", err);
    }

    // now print out some registers
    printf(">>> Emulation done. Below is the CPU context\n");

    uc_reg_read(uc, UC_ARM_REG_R0, &r0);
    uc_reg_read(uc, UC_ARM_REG_R1, &r1);
    printf(">>> R0 = 0x%x\n", r0);
    printf(">>> R1 = 0x%x\n", r1);

    uc_close(uc);
}

static void test_thumb(void)
{
    uc_engine *uc;
    uc_err err;
    uc_hook trace1, trace2;

    int sp = 0x1234; // R0 register

    printf("Emulate THUMB code\n");

    // Initialize emulator in ARM mode
    err = uc_open(UC_ARCH_ARM, UC_MODE_THUMB, &uc);
    if (err) {
        printf("Failed on uc_open() with error returned: %u (%s)\n", err,
               uc_strerror(err));
        return;
    }

    // map 2MB memory for this emulation
    uc_mem_map(uc, ADDRESS, 2 * 1024 * 1024, UC_PROT_ALL);

    // write machine code to be emulated to memory
    uc_mem_write(uc, ADDRESS, THUMB_CODE, sizeof(THUMB_CODE) - 1);

    // initialize machine registers
    uc_reg_write(uc, UC_ARM_REG_SP, &sp);

    // tracing all basic blocks with customized callback
    uc_hook_add(uc, &trace1, UC_HOOK_BLOCK, hook_block, NULL, 1, 0);

    // tracing one instruction at ADDRESS with customized callback
    uc_hook_add(uc, &trace2, UC_HOOK_CODE, hook_code, NULL, ADDRESS, ADDRESS);

    // emulate machine code in infinite time (last param = 0), or when
    // finishing all the code.
    // Note we start at ADDRESS | 1 to indicate THUMB mode.
    err = uc_emu_start(uc, ADDRESS | 1, ADDRESS + sizeof(THUMB_CODE) - 1, 0, 0);
    if (err) {
        printf("Failed on uc_emu_start() with error returned: %u\n", err);
    }

    // now print out some registers
    printf(">>> Emulation done. Below is the CPU context\n");

    uc_reg_read(uc, UC_ARM_REG_SP, &sp);
    printf(">>> SP = 0x%x\n", sp);

    uc_close(uc);
}

static void test_armeb(void)
{
    uc_engine *uc;
    uc_err err;
    uc_hook trace1, trace2;

    int r0 = 0x1234; // R0 register
    int r2 = 0x6789; // R1 register
    int r3 = 0x3333; // R2 register
    int r1;          // R1 register

    printf("Emulate ARM Big-Endian code\n");

    // Initialize emulator in ARM mode
    err = uc_open(UC_ARCH_ARM, UC_MODE_ARM + UC_MODE_BIG_ENDIAN, &uc);
    if (err) {
        printf("Failed on uc_open() with error returned: %u (%s)\n", err,
               uc_strerror(err));
        return;
    }

    // map 2MB memory for this emulation
    uc_mem_map(uc, ADDRESS, 2 * 1024 * 1024, UC_PROT_ALL);

    // write machine code to be emulated to memory
    uc_mem_write(uc, ADDRESS, ARM_CODE_EB, sizeof(ARM_CODE_EB) - 1);

    // initialize machine registers
    uc_reg_write(uc, UC_ARM_REG_R0, &r0);
    uc_reg_write(uc, UC_ARM_REG_R2, &r2);
    uc_reg_write(uc, UC_ARM_REG_R3, &r3);

    // tracing all basic blocks with customized callback
    uc_hook_add(uc, &trace1, UC_HOOK_BLOCK, hook_block, NULL, 1, 0);

    // tracing one instruction at ADDRESS with customized callback
    uc_hook_add(uc, &trace2, UC_HOOK_CODE, hook_code, NULL, ADDRESS, ADDRESS);

    // emulate machine code in infinite time (last param = 0), or when
    // finishing all the code.
    err = uc_emu_start(uc, ADDRESS, ADDRESS + sizeof(ARM_CODE_EB) - 1, 0, 0);
    if (err) {
        printf("Failed on uc_emu_start() with error returned: %u\n", err);
    }

    // now print out some registers
    printf(">>> Emulation done. Below is the CPU context\n");

    uc_reg_read(uc, UC_ARM_REG_R0, &r0);
    uc_reg_read(uc, UC_ARM_REG_R1, &r1);
    printf(">>> R0 = 0x%x\n", r0);
    printf(">>> R1 = 0x%x\n", r1);

    uc_close(uc);
}

static void test_thumbeb(void)
{
    uc_engine *uc;
    uc_err err;
    uc_hook trace1, trace2;

    int sp = 0x1234; // R0 register

    printf("Emulate THUMB Big-Endian code\n");

    // Initialize emulator in ARM mode
    err = uc_open(UC_ARCH_ARM, UC_MODE_THUMB + UC_MODE_BIG_ENDIAN, &uc);
    if (err) {
        printf("Failed on uc_open() with error returned: %u (%s)\n", err,
               uc_strerror(err));
        return;
    }

    // map 2MB memory for this emulation
    uc_mem_map(uc, ADDRESS, 2 * 1024 * 1024, UC_PROT_ALL);

    // write machine code to be emulated to memory
    uc_mem_write(uc, ADDRESS, THUMB_CODE_EB, sizeof(THUMB_CODE_EB) - 1);

    // initialize machine registers
    uc_reg_write(uc, UC_ARM_REG_SP, &sp);

    // tracing all basic blocks with customized callback
    uc_hook_add(uc, &trace1, UC_HOOK_BLOCK, hook_block, NULL, 1, 0);

    // tracing one instruction at ADDRESS with customized callback
    uc_hook_add(uc, &trace2, UC_HOOK_CODE, hook_code, NULL, ADDRESS, ADDRESS);

    // emulate machine code in infinite time (last param = 0), or when
    // finishing all the code.
    // Note we start at ADDRESS | 1 to indicate THUMB mode.
    err = uc_emu_start(uc, ADDRESS | 1, ADDRESS + sizeof(THUMB_CODE_EB) - 1, 0,
                       0);
    if (err) {
        printf("Failed on uc_emu_start() with error returned: %u\n", err);
    }

    // now print out some registers
    printf(">>> Emulation done. Below is the CPU context\n");

    uc_reg_read(uc, UC_ARM_REG_SP, &sp);
    printf(">>> SP = 0x%x\n", sp);

    uc_close(uc);
}

static void test_thumb_mrs(void)
{
    uc_engine *uc;
    uc_err err;
    uc_hook trace1, trace2;

    int pc;

    printf("Emulate THUMB MRS instruction\n");
    // 0xf3ef8014 - mrs r0, control

    // Initialize emulator in ARM mode
    err = uc_open(UC_ARCH_ARM, UC_MODE_THUMB | UC_MODE_MCLASS, &uc);
    if (err) {
        printf("Failed on uc_open() with error returned: %u (%s)\n", err,
               uc_strerror(err));
        return;
    }

    // map 2MB memory for this emulation
    uc_mem_map(uc, ADDRESS, 2 * 1024 * 1024, UC_PROT_ALL);

    // write machine code to be emulated to memory
    uc_mem_write(uc, ADDRESS, "\xef\xf3\x14\x80", 4);

    // tracing all basic blocks with customized callback
    uc_hook_add(uc, &trace1, UC_HOOK_BLOCK, hook_block, NULL, 1, 0);

    // tracing one instruction at ADDRESS with customized callback
    uc_hook_add(uc, &trace2, UC_HOOK_CODE, hook_code, NULL, ADDRESS, ADDRESS);

    // emulate machine code in infinite time (last param = 0), or when
    // finishing all the code.

    // Note we start at ADDRESS | 1 to indicate THUMB mode.
    err = uc_emu_start(uc, ADDRESS | 1, ADDRESS + 4, 0, 1);
    if (err) {
        printf("Failed on uc_emu_start() with error returned: %u\n", err);
    }

    // now print out some registers
    printf(">>> Emulation done. Below is the CPU context\n");

    uc_reg_read(uc, UC_ARM_REG_PC, &pc);
    printf(">>> PC = 0x%x\n", pc);
    if (pc != ADDRESS + 4) {
        printf("Error, PC was 0x%x, expected was 0x%x.\n", pc, ADDRESS + 4);
    }

    uc_close(uc);
}

static void test_thumb_ite_internal(bool step, uint32_t *r2_out,
                                    uint32_t *r3_out)
{
    uc_engine *uc;
    uc_err err;

    uint32_t sp = 0x1234;
    uint32_t r2 = 0, r3 = 1;

    err = uc_open(UC_ARCH_ARM, UC_MODE_THUMB, &uc);
    if (err) {
        printf("Failed on uc_open() with error returned: %u (%s)\n", err,
               uc_strerror(err));
        return;
    }

    uc_mem_map(uc, ADDRESS, 2 * 1024 * 1024, UC_PROT_ALL);

    uc_mem_write(uc, ADDRESS, ARM_THUM_COND_CODE,
                 sizeof(ARM_THUM_COND_CODE) - 1);

    uc_reg_write(uc, UC_ARM_REG_SP, &sp);

    uc_reg_write(uc, UC_ARM_REG_R2, &r2);
    uc_reg_write(uc, UC_ARM_REG_R3, &r3);

    if (!step) {
        err = uc_emu_start(uc, ADDRESS | 1,
                           ADDRESS + sizeof(ARM_THUM_COND_CODE) - 1, 0, 0);
        if (err) {
            printf("Failed on uc_emu_start() with error returned: %u\n", err);
        }
    } else {
        int i, addr = ADDRESS;
        for (i = 0; i < sizeof(ARM_THUM_COND_CODE) / 2; i++) {
            err = uc_emu_start(uc, addr | 1,
                               ADDRESS + sizeof(ARM_THUM_COND_CODE) - 1, 0, 1);
            if (err) {
                printf("Failed on uc_emu_start() with error returned: %u\n",
                       err);
            }
            uc_reg_read(uc, UC_ARM_REG_PC, &addr);
        }
    }

    uc_reg_read(uc, UC_ARM_REG_R2, &r2);
    uc_reg_read(uc, UC_ARM_REG_R3, &r3);

    uc_close(uc);

    *r2_out = r2;
    *r3_out = r3;
}

static void test_thumb_ite()
{
    uint32_t r2, r3;
    uint32_t step_r2, step_r3;

    printf("Emulate a THUMB ITE block as a whole or per instruction.\n");

    // Run once.
    printf("Running the entire binary.\n");
    test_thumb_ite_internal(false, &r2, &r3);
    printf(">>> R2: %d\n", r2);
    printf(">>> R3: %d\n\n", r3);

    // Step each instruction.
    printf("Running the binary one instruction at a time.\n");
    test_thumb_ite_internal(true, &step_r2, &step_r3);
    printf(">>> R2: %d\n", step_r2);
    printf(">>> R3: %d\n\n", step_r3);

    if (step_r2 != r2 || step_r3 != r3) {
        printf("Failed with ARM ITE blocks stepping!\n");
    }
}

int main(int argc, char **argv, char **envp)
{
    test_arm();

    printf("==========================\n");
    test_thumb();

    printf("==========================\n");
    test_armeb();

    printf("==========================\n");
    test_thumbeb();

    printf("==========================\n");
    test_thumb_mrs();

    printf("==========================\n");
    test_thumb_ite();

    return 0;
}