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#include <fcntl.h>
#include <stddef.h>
#include <sys/mman.h>
#include <sys/shm.h>
#if defined(__linux__)
#include <asm/prctl.h>
#include <sys/syscall.h>
#endif
#include "frida-gumjs.h"
#include "config.h"
#include "debug.h"
#include "instrument.h"
#include "ranges.h"
#if defined(__x86_64__)
#ifndef MAP_FIXED_NOREPLACE
#ifdef MAP_EXCL
#define MAP_FIXED_NOREPLACE MAP_EXCL | MAP_FIXED
#else
#define MAP_FIXED_NOREPLACE MAP_FIXED
#endif
#endif
gboolean instrument_is_coverage_optimize_supported(void) {
return true;
}
static gboolean instrument_coverage_in_range(gssize offset) {
return (offset >= G_MININT32 && offset <= G_MAXINT32);
}
#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;
// => 0x7ffff6cfb086: lea rsp,[rsp-0x80]
// 0x7ffff6cfb08b: pushf
// 0x7ffff6cfb08c: push rsi
// 0x7ffff6cfb08d: mov rsi,0x228
// 0x7ffff6cfb094: xchg QWORD PTR [rip+0x3136a5],rsi # 0x7ffff700e740
// 0x7ffff6cfb09b: xor rsi,0x451
// 0x7ffff6cfb0a2: add BYTE PTR [rsi+0x10000],0x1
// 0x7ffff6cfb0a9: adc BYTE PTR [rsi+0x10000],0x0
// 0x7ffff6cfb0b0: pop rsi
// 0x7ffff6cfb0b1: popf
// 0x7ffff6cfb0b2: lea rsp,[rsp+0x80]
uint8_t lea_rsp_rsp_sub_rz[5];
uint8_t push_fq;
uint8_t push_rsi;
uint8_t mov_rsi_curr_loc_shr_1[7];
uint8_t xchg_rsi_prev_loc_curr_loc[7];
uint8_t xor_rsi_curr_loc[7];
uint8_t add_rsi_1[7];
uint8_t adc_rsi_0[7];
uint8_t pop_rsi;
uint8_t pop_fq;
uint8_t lsa_rsp_rsp_add_rz[8];
} afl_log_code_asm_t;
#pragma pack(pop)
typedef union {
afl_log_code_asm_t code;
uint8_t bytes[0];
} afl_log_code;
static const afl_log_code_asm_t template =
{
.lea_rsp_rsp_sub_rz = {0x48, 0x8D, 0x64, 0x24, 0x80},
.push_fq = 0x9c,
.push_rsi = 0x56,
.mov_rsi_curr_loc_shr_1 = {0x48, 0xC7, 0xC6},
.xchg_rsi_prev_loc_curr_loc = {0x48, 0x87, 0x35},
.xor_rsi_curr_loc = {0x48, 0x81, 0xF6},
.add_rsi_1 = {0x80, 0x86, 0x00, 0x00, 0x00, 0x00, 0x01},
.adc_rsi_0 = {0x80, 0x96, 0x00, 0x00, 0x00, 0x00, 0x00},
.pop_rsi = 0x5E,
.pop_fq = 0x9D,
.lsa_rsp_rsp_add_rz = {0x48, 0x8D, 0xA4, 0x24, 0x80, 0x00, 0x00, 0x00},
}
;
static gboolean instrument_coverage_find_low(const GumRangeDetails *details,
gpointer user_data) {
static GumAddress last_limit = (64ULL << 10);
gpointer * address = (gpointer *)user_data;
if ((details->range->base_address - last_limit) > __afl_map_size) {
*address = GSIZE_TO_POINTER(last_limit);
return FALSE;
}
if (details->range->base_address > ((2ULL << 20) - __afl_map_size)) {
return FALSE;
}
last_limit = details->range->base_address + details->range->size;
return TRUE;
}
static void instrument_coverage_optimize_map_mmap_anon(gpointer address) {
__afl_area_ptr =
mmap(address, __afl_map_size, PROT_READ | PROT_WRITE,
MAP_FIXED_NOREPLACE | MAP_SHARED | MAP_ANONYMOUS, -1, 0);
if (__afl_area_ptr != address) {
FATAL("Failed to map mmap __afl_area_ptr: %d", errno);
}
}
static void instrument_coverage_optimize_map_mmap(char * shm_file_path,
gpointer address) {
int shm_fd = -1;
if (munmap(__afl_area_ptr, __afl_map_size) != 0) {
FATAL("Failed to unmap previous __afl_area_ptr");
}
__afl_area_ptr = NULL;
shm_fd = shm_open(shm_file_path, O_RDWR, DEFAULT_PERMISSION);
if (shm_fd == -1) { FATAL("shm_open() failed\n"); }
__afl_area_ptr = mmap(address, __afl_map_size, PROT_READ | PROT_WRITE,
MAP_FIXED_NOREPLACE | MAP_SHARED, shm_fd, 0);
if (__afl_area_ptr != address) {
FATAL("Failed to map mmap __afl_area_ptr: %d", errno);
}
if (close(shm_fd) != 0) { FATAL("Failed to close shm_fd"); }
}
static void instrument_coverage_optimize_map_shm(guint64 shm_env_val,
gpointer address) {
if (shmdt(__afl_area_ptr) != 0) {
FATAL("Failed to detach previous __afl_area_ptr");
}
__afl_area_ptr = shmat(shm_env_val, address, 0);
if (__afl_area_ptr != address) {
FATAL("Failed to map shm __afl_area_ptr: %d", errno);
}
}
void instrument_coverage_optimize_init(void) {
gpointer low_address = NULL;
gum_process_enumerate_ranges(GUM_PAGE_NO_ACCESS, instrument_coverage_find_low,
&low_address);
OKF("Low address: %p", low_address);
if (low_address == 0 ||
GPOINTER_TO_SIZE(low_address) > ((2UL << 20) - __afl_map_size)) {
FATAL("Invalid low_address: %p", low_address);
}
ranges_print_debug_maps();
char *shm_env = getenv(SHM_ENV_VAR);
OKF("SHM_ENV_VAR: %s", shm_env);
if (shm_env == NULL) {
WARNF("SHM_ENV_VAR not set, using anonymous map for debugging purposes");
instrument_coverage_optimize_map_mmap_anon(low_address);
} else {
guint64 shm_env_val = g_ascii_strtoull(shm_env, NULL, 10);
if (shm_env_val == 0) {
instrument_coverage_optimize_map_mmap(shm_env, low_address);
} else {
instrument_coverage_optimize_map_shm(shm_env_val, low_address);
}
}
OKF("__afl_area_ptr: %p", __afl_area_ptr);
OKF("instrument_previous_pc: %p", &instrument_previous_pc);
}
void instrument_coverage_optimize(const cs_insn * instr,
GumStalkerOutput *output) {
afl_log_code code = {0};
GumX86Writer *cw = output->writer.x86;
guint64 area_offset = instrument_get_offset_hash(GUM_ADDRESS(instr->address));
GumAddress code_addr = 0;
// gum_x86_writer_put_breakpoint(cw);
code_addr = cw->pc;
code.code = template;
gssize curr_loc_shr_1_offset =
offsetof(afl_log_code, code.mov_rsi_curr_loc_shr_1) +
sizeof(code.code.mov_rsi_curr_loc_shr_1) - sizeof(guint32);
*((guint32 *)&code.bytes[curr_loc_shr_1_offset]) =
(guint32)(area_offset >> 1);
gssize prev_loc_value =
GPOINTER_TO_SIZE(&instrument_previous_pc) -
(code_addr + offsetof(afl_log_code, code.xchg_rsi_prev_loc_curr_loc) +
sizeof(code.code.xchg_rsi_prev_loc_curr_loc));
gssize prev_loc_value_offset =
offsetof(afl_log_code, code.xchg_rsi_prev_loc_curr_loc) +
sizeof(code.code.xchg_rsi_prev_loc_curr_loc) - sizeof(gint);
if (!instrument_coverage_in_range(prev_loc_value)) {
FATAL("Patch out of range (current_pc_value1): 0x%016lX", prev_loc_value);
}
*((gint *)&code.bytes[prev_loc_value_offset]) = (gint)prev_loc_value;
gssize xor_curr_loc_offset = offsetof(afl_log_code, code.xor_rsi_curr_loc) +
sizeof(code.code.xor_rsi_curr_loc) -
sizeof(guint32);
*((guint32 *)&code.bytes[xor_curr_loc_offset]) = (guint32)(area_offset);
gssize add_rsi_1_offset = offsetof(afl_log_code, code.add_rsi_1) +
sizeof(code.code.add_rsi_1) - sizeof(guint32) - 1;
*((guint32 *)&code.bytes[add_rsi_1_offset]) =
(guint32)GPOINTER_TO_SIZE(__afl_area_ptr);
gssize adc_rsi_0_ffset = offsetof(afl_log_code, code.adc_rsi_0) +
sizeof(code.code.adc_rsi_0) - sizeof(guint32) - 1;
*((guint32 *)&code.bytes[adc_rsi_0_ffset]) =
(guint32)GPOINTER_TO_SIZE(__afl_area_ptr);
gum_x86_writer_put_bytes(cw, code.bytes, sizeof(afl_log_code));
}
void instrument_flush(GumStalkerOutput *output) {
gum_x86_writer_flush(output->writer.x86);
}
gpointer instrument_cur(GumStalkerOutput *output) {
return gum_x86_writer_cur(output->writer.x86);
}
#endif
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