8 files changed, 547 insertions, 1 deletions

diff --git a/frida_mode/src/instrument/instrument.c b/frida_mode/src/instrument/instrument.c
index 43560478..003c3d00 100644
--- a/frida_mode/src/instrument/instrument.c
+++ b/frida_mode/src/instrument/instrument.c
@@ -249,6 +249,8 @@ static void instrument_basic_block(GumStalkerIterator *iterator,
 
     }
 
+    instrument_cache(instr, output);
+
     if (js_stalker_callback(instr, begin, excluded, output)) {
 
       gum_stalker_iterator_keep(iterator);
@@ -282,6 +284,7 @@ void instrument_config(void) {
   instrument_coverage_config();
   asan_config();
   cmplog_config();
+  instrument_cache_config();
 
 }
 
@@ -392,6 +395,7 @@ void instrument_init(void) {
   instrument_coverage_init();
   instrument_coverage_optimize_init();
   instrument_debug_init();
+  instrument_cache_init();
 
 }
 
diff --git a/frida_mode/src/instrument/instrument_arm32.c b/frida_mode/src/instrument/instrument_arm32.c
index 705faa64..80f3c26d 100644
--- a/frida_mode/src/instrument/instrument_arm32.c
+++ b/frida_mode/src/instrument/instrument_arm32.c
@@ -5,6 +5,9 @@
 
 #if defined(__arm__)
 
+gboolean instrument_cache_enabled = FALSE;
+gsize    instrument_cache_size = 0;
+
 gboolean instrument_is_coverage_optimize_supported(void) {
 
   return false;
@@ -55,5 +58,27 @@ gpointer instrument_cur(GumStalkerOutput *output) {
 
 }
 
+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);
+
+}
+
 #endif
 
diff --git a/frida_mode/src/instrument/instrument_arm64.c b/frida_mode/src/instrument/instrument_arm64.c
index 4abc0625..eb736386 100644
--- a/frida_mode/src/instrument/instrument_arm64.c
+++ b/frida_mode/src/instrument/instrument_arm64.c
@@ -379,5 +379,27 @@ gpointer instrument_cur(GumStalkerOutput *output) {
 
 }
 
+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);
+
+}
+
 #endif
 
diff --git a/frida_mode/src/instrument/instrument_x64.c b/frida_mode/src/instrument/instrument_x64.c
index 4b1a2d68..0bff3e02 100644
--- a/frida_mode/src/instrument/instrument_x64.c
+++ b/frida_mode/src/instrument/instrument_x64.c
@@ -202,10 +202,17 @@ static void instrument_coverage_switch(GumStalkerObserver *self,
 
       }
 
-      if (op[0].type != X86_OP_IMM) { return; }
+      if (op[0].type != X86_OP_IMM) {
+
+        instrument_cache_insert(start_address, *target);
+        return;
+
+      }
 
       break;
     case X86_INS_RET:
+      instrument_cache_insert(start_address,
+                              (guint8 *)*target + sizeof(afl_log_code));
       break;
     default:
       return;
diff --git a/frida_mode/src/instrument/instrument_x64_cache.c b/frida_mode/src/instrument/instrument_x64_cache.c
new file mode 100644
index 00000000..3ea4421a
--- /dev/null
+++ b/frida_mode/src/instrument/instrument_x64_cache.c
@@ -0,0 +1,435 @@
+#include <sys/mman.h>
+#include <sys/resource.h>
+
+#include "instrument.h"
+#include "util.h"
+
+#if defined(__x86_64__)
+
+  #define INVALID 1
+  #define DEFAULT_CACHE_SIZE (256ULL << 20)
+
+gboolean         instrument_cache_enabled = TRUE;
+gsize            instrument_cache_size = DEFAULT_CACHE_SIZE;
+static gpointer *map_base = MAP_FAILED;
+
+void instrument_cache_config(void) {
+
+  instrument_cache_enabled = (getenv("AFL_FRIDA_INST_NO_CACHE") == NULL);
+
+  if (getenv("AFL_FRIDA_INST_CACHE_SIZE") != NULL) {
+
+    if (!instrument_cache_enabled) {
+
+      FFATAL(
+          "AFL_FRIDA_INST_CACHE_SIZE incomatible with "
+          "AFL_FRIDA_INST_NO_CACHE");
+
+    }
+
+    instrument_cache_size =
+        util_read_address("AFL_FRIDA_INST_CACHE_SIZE", DEFAULT_CACHE_SIZE);
+    util_log2(instrument_cache_size);
+
+  }
+
+}
+
+void instrument_cache_init(void) {
+
+  FOKF(cBLU "Instrumentation" cRST " - " cGRN "cache:" cYEL " [%c]",
+       instrument_cache_enabled ? 'X' : ' ');
+  if (!instrument_cache_enabled) { return; }
+
+  FOKF(cBLU "Instrumentation" cRST " - " cGRN "cache size:" cYEL " [0x%016lX]",
+       instrument_cache_size);
+
+  const struct rlimit data_limit = {.rlim_cur = RLIM_INFINITY,
+                                    .rlim_max = RLIM_INFINITY};
+
+  if (setrlimit(RLIMIT_AS, &data_limit) != 0) {
+
+    FFATAL("Failed to setrlimit: %d", errno);
+
+  }
+
+  map_base =
+      gum_memory_allocate(NULL, instrument_cache_size, instrument_cache_size,
+                          GUM_PAGE_READ | GUM_PAGE_WRITE);
+  if (map_base == MAP_FAILED) { FFATAL("Failed to map segment: %d", errno); }
+
+  FOKF(cBLU "Instrumentation" cRST " - " cGRN "cache addr:" cYEL " [0x%016lX]",
+       GUM_ADDRESS(map_base));
+
+}
+
+static gpointer *instrument_cache_get_addr(gpointer addr) {
+
+  gsize mask = (instrument_cache_size / sizeof(gpointer)) - 1;
+  return &map_base[GPOINTER_TO_SIZE(addr) & mask];
+
+}
+
+void instrument_cache_insert(gpointer real_address, gpointer code_address) {
+
+  if (!instrument_cache_enabled) { return; }
+
+  gpointer *target = instrument_cache_get_addr(real_address);
+  if (*target == code_address) {
+
+    return;
+
+  } else if (*target == NULL) {
+
+    *target = code_address;
+
+  } else {
+
+    *target = GSIZE_TO_POINTER(INVALID);
+
+  }
+
+}
+
+static gboolean instrument_cache_relocate(GumAddress old_pc, GumAddress new_pc,
+                                          gint32  old_offset,
+                                          gint32 *new_offset) {
+
+  guint64 old_target = old_pc + old_offset;
+  gint64  relocated = old_target - new_pc;
+
+  if (relocated > G_MAXINT32 || relocated < G_MININT32) { return FALSE; }
+
+  *new_offset = relocated;
+  return TRUE;
+
+}
+
+static void instrument_cache_rewrite_branch_insn(const cs_insn *   instr,
+                                                 GumStalkerOutput *output) {
+
+  GumX86Writer *cw = output->writer.x86;
+  cs_x86 *      x86 = &instr->detail->x86;
+  guint8        modified[sizeof(instr->bytes)] = {0};
+  guint8        offset = 0;
+  guint8        skip = 0;
+
+  g_assert(sizeof(x86->prefix) == 4);
+  g_assert(sizeof(x86->opcode) == 4);
+
+  /*
+   * If the target is simply RAX, we can skip writing the code to load the
+   * RIP
+   */
+  if (x86->operands[0].type == X86_OP_REG ||
+      x86->operands[0].reg == X86_REG_RAX) {
+
+    return;
+
+  }
+
+  /* Write the prefix */
+  for (gsize i = 0; i < sizeof(x86->prefix); i++) {
+
+    if (x86->prefix[i] != 0) {
+
+      if (x86->prefix[i] == 0xf2) {
+
+        skip++;
+
+      } else {
+
+        modified[offset++] = x86->prefix[i];
+        skip++;
+
+      }
+
+    }
+
+  }
+
+  /* Write the REX */
+  if (x86->rex == 0) {
+
+    /*
+     * CALL (near) and JMP (near) default to 64-bit operands, MOV does not,
+     * write REX.W
+     */
+    modified[offset++] = 0x48;
+
+  } else {
+
+    if ((x86->rex & 0xF8) != 0x40) {
+
+      FATAL("Unexpected REX byte: 0x%02x", x86->rex);
+
+    }
+
+    modified[offset++] = x86->rex | 0x08;
+    skip++;
+
+  }
+
+  /*
+   * CALL is FF /2, JMP is FF /4. The remaining op-code fields should thus be
+   * unused
+   */
+
+  if (x86->opcode[0] != 0xFF || x86->opcode[1] != 0x00 ||
+      x86->opcode[2] != 0x00 || x86->opcode[3] != 0x00) {
+
+    FFATAL("Unexpected Op-code: 0x%02x 0x%02x 0x%02x 0x%02x", x86->opcode[0],
+           x86->opcode[1], x86->opcode[2], x86->opcode[3]);
+
+  }
+
+  /* The reg field of the ModRM should be set to 2 for CALL and 4 for JMP */
+  guint8 reg = (x86->modrm >> 3) & 7;
+  if (reg != 0x4 && reg != 0x2) {
+
+    FFATAL("Unexpected Reg: 0x%02x, ModRM: 0x%02x", reg, x86->modrm);
+
+  }
+
+  /* MOV */
+  modified[offset++] = 0x8b;
+  skip++;
+
+  /* Clear the reg field (RAX) */
+  modified[offset++] = x86->modrm & 0xc7;
+  skip++;
+
+  /* Operands */
+  guint8 op_len = instr->size - skip;
+
+  /* If our branch was RIP relative, we'll need to fix-up the offset */
+  if (x86->operands[0].type == X86_OP_MEM &&
+      x86->operands[0].mem.base == X86_REG_RIP) {
+
+    /* RIP relative offsets should be 32-bits */
+    if (op_len != sizeof(gint32)) {
+
+      FFATAL("Unexpected operand length: %d\n", op_len);
+
+    }
+
+    gint32 old_offset = *(gint32 *)&instr->bytes[skip];
+    gint32 new_offset = 0;
+    if (instrument_cache_relocate(instr->address, cw->pc, old_offset,
+                                  &new_offset)) {
+
+      gint32 *output = (gint32 *)&modified[offset];
+      *output = new_offset;
+      offset += sizeof(gint32);
+
+    } else {
+
+      GumAddress target = instr->address + old_offset;
+      gum_x86_writer_put_mov_reg_address(cw, GUM_REG_RAX, target);
+      gum_x86_writer_put_mov_reg_reg_ptr(cw, GUM_REG_RAX, GUM_REG_RAX);
+      return;
+
+    }
+
+  } else {
+
+    for (int i = 0; i < op_len; i++) {
+
+      guint8 val = instr->bytes[i + skip];
+      modified[offset++] = val;
+
+    }
+
+  }
+
+  gum_x86_writer_put_bytes(cw, modified, offset);
+
+}
+
+static void instrument_cache_write_push_frame(GumX86Writer *cw) {
+
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_XSP, -(GUM_RED_ZONE_SIZE + (1 * sizeof(gpointer))),
+      GUM_REG_XAX);
+  gum_x86_writer_put_lahf(cw);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_XSP, -(GUM_RED_ZONE_SIZE + (2 * sizeof(gpointer))),
+      GUM_REG_XAX);
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_XSP, -(GUM_RED_ZONE_SIZE + (3 * sizeof(gpointer))),
+      GUM_REG_XBX);
+
+}
+
+static void instrument_cache_write_pop_frame(GumX86Writer *cw) {
+
+  gum_x86_writer_put_mov_reg_reg_offset_ptr(
+      cw, GUM_REG_XBX, GUM_REG_XSP,
+      -(GUM_RED_ZONE_SIZE + (3 * sizeof(gpointer))));
+  gum_x86_writer_put_mov_reg_reg_offset_ptr(
+      cw, GUM_REG_XAX, GUM_REG_XSP,
+      -(GUM_RED_ZONE_SIZE + (2 * sizeof(gpointer))));
+  gum_x86_writer_put_sahf(cw);
+  gum_x86_writer_put_mov_reg_reg_offset_ptr(
+      cw, GUM_REG_XAX, GUM_REG_XSP,
+      -(GUM_RED_ZONE_SIZE + (1 * sizeof(gpointer))));
+
+}
+
+static void instrument_cache_write_lookup(GumX86Writer *cw) {
+
+  /* &map_base[GPOINTER_TO_SIZE(addr) & MAP_MASK]; */
+
+  gsize mask = (instrument_cache_size / sizeof(gpointer)) - 1;
+  gum_x86_writer_put_mov_reg_u64(cw, GUM_REG_XBX, mask);
+  gum_x86_writer_put_and_reg_reg(cw, GUM_REG_XAX, GUM_REG_XBX);
+  gum_x86_writer_put_shl_reg_u8(cw, GUM_REG_XAX, util_log2(sizeof(gpointer)));
+  gum_x86_writer_put_mov_reg_u64(cw, GUM_REG_XBX, GPOINTER_TO_SIZE(map_base));
+  gum_x86_writer_put_add_reg_reg(cw, GUM_REG_XAX, GUM_REG_XBX);
+
+  /* Read the return address lookup */
+  gum_x86_writer_put_mov_reg_reg_ptr(cw, GUM_REG_XAX, GUM_REG_XAX);
+
+}
+
+void instrument_cache_jmp_call(const cs_insn *instr, GumStalkerOutput *output) {
+
+  GumX86Writer *cw = output->writer.x86;
+  cs_x86 *      x86 = &instr->detail->x86;
+
+  if (x86->op_count != 1) { FFATAL("Unexpected operand count"); }
+
+  if (x86->operands[0].type == X86_OP_IMM) { return; }
+
+  gconstpointer null = cw->code;
+
+  instrument_cache_write_push_frame(cw);
+
+  /*
+   * We are about to re-write the CALL or JMP instruction, but replace the
+   * op-code with that for a MOV into RAX. Since we are keeping the operand from
+   * the JMP exactly the same, it is imperative that the target register state
+   * be exactly the same as how the target left it. Since `LAHF` spoils `RAX` we
+   * must restore it from the stack. We also must avoid adjusting `RSP`, so we
+   * use `MOV` instructions to store our context into the stack beyond the
+   * red-zone.
+   */
+  gum_x86_writer_put_mov_reg_reg_offset_ptr(
+      cw, GUM_REG_XAX, GUM_REG_XSP,
+      -(GUM_RED_ZONE_SIZE + (1 * sizeof(gpointer))));
+
+  instrument_cache_rewrite_branch_insn(instr, output);
+
+  instrument_cache_write_lookup(cw);
+
+  /* Test if its set*/
+  gum_x86_writer_put_cmp_reg_i32(cw, GUM_REG_XAX, INVALID);
+  gum_x86_writer_put_jcc_short_label(cw, X86_INS_JLE, null, GUM_UNLIKELY);
+
+  /* If it's set, then stash the address beyond the red-zone */
+  gum_x86_writer_put_mov_reg_offset_ptr_reg(
+      cw, GUM_REG_XSP, -(GUM_RED_ZONE_SIZE + (4 * sizeof(gpointer))),
+      GUM_REG_XAX);
+
+  if (instr->id == X86_INS_JMP) {
+
+    instrument_cache_write_pop_frame(cw);
+    gum_x86_writer_put_jmp_reg_offset_ptr(
+        cw, GUM_REG_XSP, -(GUM_RED_ZONE_SIZE + (4 * sizeof(gpointer))));
+
+  } else {
+
+    gum_x86_writer_put_mov_reg_address(
+        cw, GUM_REG_XAX, GUM_ADDRESS(instr->address + instr->size));
+    gum_x86_writer_put_mov_reg_offset_ptr_reg(cw, GUM_REG_XSP,
+                                              -sizeof(gpointer), GUM_REG_XAX);
+
+    instrument_cache_write_pop_frame(cw);
+
+    gum_x86_writer_put_lea_reg_reg_offset(cw, GUM_REG_XSP, GUM_REG_XSP,
+                                          -sizeof(gpointer));
+    gum_x86_writer_put_jmp_reg_offset_ptr(
+        cw, GUM_REG_XSP, -(GUM_RED_ZONE_SIZE + ((4 - 1) * sizeof(gpointer))));
+
+  }
+
+  /* Tidy up our mess and let FRIDA handle it */
+  gum_x86_writer_put_label(cw, null);
+  instrument_cache_write_pop_frame(cw);
+
+}
+
+void instrument_cache_ret(const cs_insn *instr, GumStalkerOutput *output) {
+
+  GumX86Writer *cw = output->writer.x86;
+  cs_x86 *      x86 = &instr->detail->x86;
+  guint16       n = 0;
+
+  if (x86->op_count != 0) {
+
+    if (x86->operands[0].type != X86_OP_IMM) {
+
+      FFATAL("Unexpected operand type");
+
+    }
+
+    n = x86->operands[0].imm;
+
+  }
+
+  gconstpointer null = cw->code;
+
+  instrument_cache_write_push_frame(cw);
+
+  gum_x86_writer_put_mov_reg_reg_ptr(cw, GUM_REG_XAX, GUM_REG_XSP);
+
+  instrument_cache_write_lookup(cw);
+
+  /* Test if its set*/
+  gum_x86_writer_put_cmp_reg_i32(cw, GUM_REG_XAX, INVALID);
+  gum_x86_writer_put_jcc_short_label(cw, X86_INS_JLE, null, GUM_UNLIKELY);
+
+  /* If it's set, then overwrite our return address and return */
+  gum_x86_writer_put_mov_reg_ptr_reg(cw, GUM_REG_XSP, GUM_REG_XAX);
+  instrument_cache_write_pop_frame(cw);
+
+  if (n == 0) {
+
+    gum_x86_writer_put_ret(cw);
+
+  } else {
+
+    gum_x86_writer_put_ret_imm(cw, n);
+
+  }
+
+  /* Tidy up our mess and let FRIDA handle it */
+  gum_x86_writer_put_label(cw, null);
+  instrument_cache_write_pop_frame(cw);
+
+}
+
+void instrument_cache(const cs_insn *instr, GumStalkerOutput *output) {
+
+  if (!instrument_cache_enabled) { return; }
+
+  switch (instr->id) {
+
+    case X86_INS_RET:
+      instrument_cache_ret(instr, output);
+      break;
+
+    case X86_INS_CALL:
+    case X86_INS_JMP:
+      instrument_cache_jmp_call(instr, output);
+      break;
+
+    default:
+      return;
+
+  }
+
+}
+
+#endif
+
diff --git a/frida_mode/src/instrument/instrument_x86.c b/frida_mode/src/instrument/instrument_x86.c
index 916cd0e2..6a899248 100644
--- a/frida_mode/src/instrument/instrument_x86.c
+++ b/frida_mode/src/instrument/instrument_x86.c
@@ -6,6 +6,9 @@
 
 #if defined(__i386__)
 
+gboolean instrument_cache_enabled = FALSE;
+gsize    instrument_cache_size = 0;
+
 static GHashTable *coverage_blocks = NULL;
 
   #pragma pack(push, 1)
@@ -242,5 +245,27 @@ gpointer instrument_cur(GumStalkerOutput *output) {
 
 }
 
+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);
+
+}
+
 #endif
 
diff --git a/frida_mode/src/js/api.js b/frida_mode/src/js/api.js
index 82b8e63d..c1c9d36f 100644
--- a/frida_mode/src/js/api.js
+++ b/frida_mode/src/js/api.js
@@ -69,6 +69,12 @@ class Afl {
         Afl.jsApiSetBackpatchDisable();
     }
     /**
+     * See `AFL_FRIDA_INST_NO_CACHE`.
+     */
+    static setCacheDisable() {
+        Afl.jsApiSetCacheDisable();
+    }
+    /**
      * See `AFL_FRIDA_DEBUG_MAPS`.
      */
     static setDebugMaps() {
@@ -92,6 +98,13 @@ class Afl {
         Afl.jsApiAflSharedMemFuzzing.writeInt(1);
     }
     /**
+     * See `AFL_FRIDA_INST_CACHE_SIZE`. This function takes a single `number`
+     * as an argument.
+     */
+    static setInstrumentCacheSize(size) {
+        Afl.jsApiSetInstrumentCacheSize(size);
+    }
+    /**
      * See `AFL_FRIDA_INST_COVERAGE_FILE`. This function takes a single `string`
      * as an argument.
      */
@@ -299,8 +312,10 @@ Afl.jsApiAflSharedMemFuzzing = Afl.jsApiGetSymbol("__afl_sharedmem_fuzzing");
 Afl.jsApiDone = Afl.jsApiGetFunction("js_api_done", "void", []);
 Afl.jsApiError = Afl.jsApiGetFunction("js_api_error", "void", ["pointer"]);
 Afl.jsApiSetBackpatchDisable = Afl.jsApiGetFunction("js_api_set_backpatch_disable", "void", []);
+Afl.jsApiSetCacheDisable = Afl.jsApiGetFunction("js_api_set_cache_disable", "void", []);
 Afl.jsApiSetDebugMaps = Afl.jsApiGetFunction("js_api_set_debug_maps", "void", []);
 Afl.jsApiSetEntryPoint = Afl.jsApiGetFunction("js_api_set_entrypoint", "void", ["pointer"]);
+Afl.jsApiSetInstrumentCacheSize = Afl.jsApiGetFunction("js_api_set_instrument_cache_size", "void", ["size_t"]);
 Afl.jsApiSetInstrumentCoverageFile = Afl.jsApiGetFunction("js_api_set_instrument_coverage_file", "void", ["pointer"]);
 Afl.jsApiSetInstrumentDebugFile = Afl.jsApiGetFunction("js_api_set_instrument_debug_file", "void", ["pointer"]);
 Afl.jsApiSetInstrumentInstructions = Afl.jsApiGetFunction("js_api_set_instrument_instructions", "void", []);
diff --git a/frida_mode/src/js/js_api.c b/frida_mode/src/js/js_api.c
index 89df7803..7cc8ffc7 100644
--- a/frida_mode/src/js/js_api.c
+++ b/frida_mode/src/js/js_api.c
@@ -262,6 +262,19 @@ __attribute__((visibility("default"))) void js_api_set_stalker_adjacent_blocks(
 
 }
 
+__attribute__((visibility("default"))) void js_api_set_cache_disable(void) {
+
+  instrument_cache_enabled = FALSE;
+
+}
+
+__attribute__((visibility("default"))) void js_api_set_instrument_cache_size(
+    gsize size) {
+
+  instrument_cache_size = size;
+
+}
+
 __attribute__((visibility("default"))) void js_api_set_js_main_hook(
     const js_main_hook_t hook) {