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#include "frida-gumjs.h"
#include "instrument.h"
#include "stalker.h"
#include "util.h"
#if defined(__arm__)
#define PAGE_MASK (~(GUM_ADDRESS(0xfff)))
#define PAGE_ALIGNED(x) ((GUM_ADDRESS(x) & PAGE_MASK) == GUM_ADDRESS(x))
gboolean instrument_cache_enabled = FALSE;
gsize instrument_cache_size = 0;
static GHashTable *coverage_blocks = NULL;
extern __thread guint64 instrument_previous_pc;
__attribute__((aligned(0x1000))) static guint8 area_ptr_dummy[MAP_INITIAL_SIZE];
#pragma pack(push, 1)
typedef struct {
// cur_location = (block_address >> 4) ^ (block_address << 8);
// shared_mem[cur_location ^ prev_location]++;
// prev_location = cur_location >> 1;
// str r0, [sp, #-128] ; 0xffffff80
// str r1, [sp, #-132] ; 0xffffff7c
// ldr r0, [pc, #-20] ; 0xf691b29c
// ldrh r1, [r0]
// movw r0, #33222 ; 0x81c6
// eor r0, r0, r1
// ldr r1, [pc, #-40] ; 0xf691b298
// add r1, r1, r0
// ldrb r0, [r1]
// add r0, r0, #1
// add r0, r0, r0, lsr #8
// strb r0, [r1]
// movw r0, #49379 ; 0xc0e3
// ldr r1, [pc, #-64] ; 0xf691b29c
// strh r0, [r1]
// ldr r1, [sp, #-132] ; 0xffffff7c
// ldr r0, [sp, #-128] ; 0xffffff80
uint32_t b_code; /* b imm */
uint8_t *shared_mem;
uint64_t *prev_location;
/* code */
/* save regs */
uint32_t str_r0_sp_rz; /* str r0, [sp - RED_ZONE] */
uint32_t str_r1_sp_rz_4; /* str r1, [sp - (RED_ZONE + 4)] */
/* load prev */
uint32_t ldr_r0_pprev; /* ldr r0, [pc-x] */
uint32_t ldrh_r1_r0; /* ldrh r1, [r0] */
/* load curr */
uint32_t mov_r0_block_id; /* mov r0, #imm16 */
/* calculate new */
uint32_t eor_r0_r0_r1; /* eor r0, r0, r1 */
/* load map */
uint32_t ldr_r1_pmap; /* ldr r1, [pc-x] */
/* calculate offset */
uint32_t add_r1_r1_r0; /* add r1, r1, r0 */
/* Load the value */
uint32_t ldrb_r0_r1; /* ldrb r0, [r1] */
/* Increment the value */
uint32_t add_r0_r0_1; /* add r0, r0, #1 */
uint32_t add_r0_r0_r0_lsr_8; /* add r0, r0, r0, lsr #8 */
/* Save the value */
uint32_t strb_r0_r1; /* strb r0, [r1] */
/* load curr shifted */
uint32_t mov_r0_block_id_shr_1; /* mov r0, #imm16 >> 1*/
/* Update prev */
uint32_t ldr_r1_pprev; /* ldr r1, [pc-x] */
uint32_t strh_r0_r1; /* strh r0, [r1] */
/* restore regs */
uint32_t ldr_r1_sp_rz_4; /* ldr r1, [sp - (RED_ZONE + 4)] */
uint32_t ldr_r0_sp_rz; /* ldr r0, [sp - RED_ZONE] */
} afl_log_code_asm_t;
typedef union {
afl_log_code_asm_t code;
uint8_t bytes[0];
} afl_log_code;
#pragma pack(pop)
static const afl_log_code_asm_t template =
{
.b_code = GUINT32_TO_LE(0xea000001),
.shared_mem = (uint8_t *)GUINT32_TO_LE(0xcefaadde),
.prev_location = (uint64_t *)GUINT32_TO_LE(0xadba0df0),
.str_r0_sp_rz = GUINT32_TO_LE(0xe50d0080),
.str_r1_sp_rz_4 = GUINT32_TO_LE(0xe50d1084),
.ldr_r0_pprev = GUINT32_TO_LE(0xe51f0014),
.ldrh_r1_r0 = GUINT32_TO_LE(0xe1d010b0),
.mov_r0_block_id = GUINT32_TO_LE(0xe3000000),
.eor_r0_r0_r1 = GUINT32_TO_LE(0xe0200001),
.ldr_r1_pmap = GUINT32_TO_LE(0xe51f1028),
.add_r1_r1_r0 = GUINT32_TO_LE(0xe0811000),
.ldrb_r0_r1 = GUINT32_TO_LE(0xe5d10000),
.add_r0_r0_1 = GUINT32_TO_LE(0xe2800001),
.add_r0_r0_r0_lsr_8 = GUINT32_TO_LE(0xe0800420),
.strb_r0_r1 = GUINT32_TO_LE(0xe5c10000),
.mov_r0_block_id_shr_1 = GUINT32_TO_LE(0xe3000000),
.ldr_r1_pprev = GUINT32_TO_LE(0xe51f1040),
.strh_r0_r1 = GUINT32_TO_LE(0xe1c100b0),
.ldr_r1_sp_rz_4 = GUINT32_TO_LE(0xe51d1084),
.ldr_r0_sp_rz = GUINT32_TO_LE(0xe51d0080),
}
;
gboolean instrument_is_coverage_optimize_supported(void) {
return true;
}
static void instrument_coverage_switch(GumStalkerObserver *self,
gpointer from_address,
gpointer start_address, void *from_insn,
gpointer *target) {
UNUSED_PARAMETER(self);
UNUSED_PARAMETER(from_address);
UNUSED_PARAMETER(start_address);
UNUSED_PARAMETER(from_insn);
if (!g_hash_table_contains(coverage_blocks, GSIZE_TO_POINTER(*target))) {
return;
}
*target =
(guint8 *)*target + G_STRUCT_OFFSET(afl_log_code_asm_t, str_r0_sp_rz);
}
static void instrument_coverage_suppress_init(void) {
static gboolean initialized = false;
if (initialized) { return; }
initialized = true;
GumStalkerObserver *observer = stalker_get_observer();
GumStalkerObserverInterface *iface = GUM_STALKER_OBSERVER_GET_IFACE(observer);
iface->switch_callback = instrument_coverage_switch;
coverage_blocks = g_hash_table_new(g_direct_hash, g_direct_equal);
if (coverage_blocks == NULL) {
FATAL("Failed to g_hash_table_new, errno: %d", errno);
}
}
static void patch_t3_insn(uint32_t *insn, uint16_t val) {
uint32_t orig = GUINT32_FROM_LE(*insn);
uint32_t imm12 = (val & 0xfff);
uint32_t imm4 = (val >> 12);
orig |= imm12;
orig |= (imm4 << 16);
*insn = GUINT32_TO_LE(orig);
}
void instrument_coverage_optimize(const cs_insn *instr,
GumStalkerOutput *output) {
afl_log_code code = {0};
GumArmWriter *cw = output->writer.arm;
gpointer block_start;
guint64 area_offset = instrument_get_offset_hash(GUM_ADDRESS(instr->address));
gsize map_size_pow2;
gsize area_offset_ror;
instrument_coverage_suppress_init();
block_start = GSIZE_TO_POINTER(GUM_ADDRESS(cw->code));
if (!g_hash_table_add(coverage_blocks, block_start)) {
FATAL("Failed - g_hash_table_add");
}
code.code = template;
g_assert(PAGE_ALIGNED(__afl_area_ptr));
map_size_pow2 = util_log2(__afl_map_size);
area_offset_ror = util_rotate(area_offset, 1, map_size_pow2);
code.code.shared_mem = __afl_area_ptr;
code.code.prev_location = instrument_previous_pc_addr;
patch_t3_insn(&code.code.mov_r0_block_id, (uint16_t)area_offset);
patch_t3_insn(&code.code.mov_r0_block_id_shr_1, (uint16_t)area_offset_ror);
// gum_arm_writer_put_breakpoint(cw);
gum_arm_writer_put_bytes(cw, code.bytes, sizeof(afl_log_code));
}
void instrument_coverage_optimize_insn(const cs_insn *instr,
GumStalkerOutput *output) {
UNUSED_PARAMETER(instr);
UNUSED_PARAMETER(output);
}
void instrument_coverage_optimize_init(void) {
char *shm_env = getenv(SHM_ENV_VAR);
FVERBOSE("SHM_ENV_VAR: %s", shm_env);
if (shm_env == NULL) {
FWARNF("SHM_ENV_VAR not set, using dummy for debugging purposes");
__afl_area_ptr = area_ptr_dummy;
memset(area_ptr_dummy, '\0', sizeof(area_ptr_dummy));
}
FVERBOSE("__afl_area_ptr: %p", __afl_area_ptr);
if (instrument_previous_pc_addr == NULL) {
instrument_previous_pc_addr = &instrument_previous_pc;
*instrument_previous_pc_addr = instrument_hash_zero;
FVERBOSE("instrument_previous_pc_addr: %p", instrument_previous_pc_addr);
}
}
void instrument_flush(GumStalkerOutput *output) {
if (output->encoding == GUM_INSTRUCTION_SPECIAL) {
gum_thumb_writer_flush(output->writer.thumb);
} else {
gum_arm_writer_flush(output->writer.arm);
}
}
gpointer instrument_cur(GumStalkerOutput *output) {
gpointer curr = NULL;
if (output->encoding == GUM_INSTRUCTION_SPECIAL) {
curr = gum_thumb_writer_cur(output->writer.thumb);
} else {
curr = gum_arm_writer_cur(output->writer.arm);
}
return curr;
}
void instrument_cache_config(void) {
}
void instrument_cache_init(void) {
}
void instrument_cache_insert(gpointer real_address, gpointer code_address) {
UNUSED_PARAMETER(real_address);
UNUSED_PARAMETER(code_address);
}
void instrument_cache(const cs_insn *instr, GumStalkerOutput *output) {
UNUSED_PARAMETER(instr);
UNUSED_PARAMETER(output);
}
void instrument_write_regs(GumCpuContext *cpu_context, gpointer user_data) {
int fd = (int)user_data;
instrument_regs_format(fd,
"r0 : 0x%08x, r1 : 0x%08x, r2 : 0x%08x, r3 : 0x%08x\n",
cpu_context->r[0], cpu_context->r[2],
cpu_context->r[1], cpu_context->r[3]);
instrument_regs_format(fd,
"r4 : 0x%08x, r5 : 0x%08x, r6 : 0x%08x, r7 : 0x%08x\n",
cpu_context->r[4], cpu_context->r[5],
cpu_context->r[6], cpu_context->r[7]);
instrument_regs_format(
fd, "r8 : 0x%08x, r9 : 0x%08x, r10: 0x%08x, r11: 0x%08x\n",
cpu_context->r8, cpu_context->r9, cpu_context->r10, cpu_context->r11);
instrument_regs_format(
fd, "r12: 0x%08x, sp : 0x%08x, lr : 0x%08x, pc : 0x%08x\n",
cpu_context->r12, cpu_context->sp, cpu_context->lr, cpu_context->pc);
instrument_regs_format(fd, "cpsr: 0x%08x\n\n", cpu_context->cpsr);
}
#endif
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