8 files changed, 1061 insertions, 0 deletions
diff --git a/utils/afl_untracer/Makefile b/utils/afl_untracer/Makefile
new file mode 100644
index 00000000..14a09b41
--- /dev/null
+++ b/utils/afl_untracer/Makefile
@@ -0,0 +1,16 @@
+ifdef DEBUG
+  OPT=-O0
+else
+  OPT=-O3
+endif
+
+all:	afl-untracer libtestinstr.so
+
+afl-untracer:	afl-untracer.c
+	$(CC) $(OPT) -I../../include -g -o afl-untracer afl-untracer.c -ldl
+
+libtestinstr.so:	libtestinstr.c
+	$(CC) -g -O0 -fPIC -o libtestinstr.so -shared libtestinstr.c
+
+clean:
+	rm -f afl-untracer libtestinstr.so *~ core
diff --git a/utils/afl_untracer/README.md b/utils/afl_untracer/README.md
new file mode 100644
index 00000000..ada0c916
--- /dev/null
+++ b/utils/afl_untracer/README.md
@@ -0,0 +1,60 @@
+# afl-untracer - fast fuzzing of binary-only libraries
+
+## Introduction
+
+afl-untracer is an example skeleton file which can easily be used to fuzz
+a closed source library.
+
+It requires less memory and is x3-5 faster than qemu_mode however it is way
+more course grained and does not provide interesting features like compcov
+or cmplog.
+
+Supported is so far Intel (i386/x86_64) and AARCH64.
+
+## How-to
+
+### Modify afl-untracer.c
+
+Read and modify afl-untracer.c then `make`.
+To adapt afl-untracer.c to your needs, read the header of the file and then
+search and edit the `STEP 1`, `STEP 2` and `STEP 3` locations.
+
+### Generate patches.txt file
+
+To generate the `patches.txt` file for your target library use the
+`ida_get_patchpoints.py` script for IDA Pro or
+`ghidra_get_patchpoints.java` for Ghidra.
+
+The patches.txt file has to be pointed to by `AFL_UNTRACER_FILE`.
+
+To easily run the scripts without needing to run the GUI with Ghidra:
+```
+/opt/ghidra/support/analyzeHeadless /tmp/ tmp$$ -import libtestinstr.so -postscript ./ghidra_get_patchpoints.java
+rm -rf /tmp/tmp$$
+```
+The file is created at `~/Desktop/patches.txt`
+
+### Fuzzing
+
+Example (after modifying afl-untracer.c to your needs, compiling and creating
+patches.txt):
+```
+LD_LIBRARY_PATH=/path/to/target/library AFL_UNTRACER_FILE=./patches.txt afl-fuzz -i in -o out -- ./afl-untracer
+```
+(or even remote via afl-network-proxy).
+
+### Testing and debugging
+
+For testing/debugging you can try:
+```
+make DEBUG=1
+AFL_UNTRACER_FILE=./patches.txt AFL_DEBUG=1 gdb ./afl-untracer
+```
+and then you can easily set breakpoints to "breakpoint" and "fuzz".
+
+# Background
+
+This idea is based on [UnTracer](https://github.com/FoRTE-Research/UnTracer-AFL)
+and modified by [Trapfuzz](https://github.com/googleprojectzero/p0tools/tree/master/TrapFuzz).
+This implementation is slower because the traps are not patched out with each
+run, but on the other hand gives much better coverage information.
diff --git a/utils/afl_untracer/TODO b/utils/afl_untracer/TODO
new file mode 100644
index 00000000..fffffacf
--- /dev/null
+++ b/utils/afl_untracer/TODO
@@ -0,0 +1,2 @@
+ * add shmem fuzzing
+ * add snapshot feature?
diff --git a/utils/afl_untracer/afl-untracer.c b/utils/afl_untracer/afl-untracer.c
new file mode 100644
index 00000000..cb6f948c
--- /dev/null
+++ b/utils/afl_untracer/afl-untracer.c
@@ -0,0 +1,768 @@
+/*
+   american fuzzy lop++ - afl-untracer skeleton example
+   ---------------------------------------------------
+
+   Written by Marc Heuse <mh@mh-sec.de>
+
+   Copyright 2019-2020 AFLplusplus Project. All rights reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at:
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+
+   HOW-TO
+   ======
+
+   You only need to change the following:
+
+   1. decide if you want to receive data from stdin [DEFAULT] or file(name)
+      -> use_stdin = 0 if via file, and what the maximum input size is
+   2. dl load the library you want to fuzz, lookup the functions you need
+      and setup the calls to these
+   3. in the while loop you call the functions in the necessary order -
+      incl the cleanup. the cleanup is important!
+
+   Just look these steps up in the code, look for "// STEP x:"
+
+
+*/
+
+#define __USE_GNU
+#define _GNU_SOURCE
+
+#ifdef __ANDROID__
+  #include "android-ashmem.h"
+#endif
+#include "config.h"
+#include "types.h"
+#include "debug.h"
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <signal.h>
+#include <unistd.h>
+#include <string.h>
+#include <assert.h>
+#include <stdint.h>
+#include <errno.h>
+#include <dlfcn.h>
+#include <fcntl.h>
+#include <pthread.h>
+
+#include <sys/mman.h>
+#include <sys/shm.h>
+#include <sys/wait.h>
+#include <sys/types.h>
+#include <sys/personality.h>
+
+#if defined(__linux__)
+  #include <sys/ucontext.h>
+#elif defined(__APPLE__) && defined(__LP64__)
+  #include <mach-o/dyld_images.h>
+#elif defined(__FreeBSD__)
+  #include <sys/sysctl.h>
+  #include <sys/user.h>
+#else
+  #error "Unsupported platform"
+#endif
+
+#define MEMORY_MAP_DECREMENT 0x200000000000
+#define MAX_LIB_COUNT 128
+
+// STEP 1:
+
+/* here you need to specify the parameter for the target function */
+static void *(*o_function)(u8 *buf, int len);
+
+/* use stdin (1) or a file on the commandline (0) */
+static u32 use_stdin = 1;
+
+/* This is were the testcase data is written into */
+static u8 buf[10000];  // this is the maximum size for a test case! set it!
+
+/* If you want to have debug output set this to 1, can also be set with
+   AFL_DEBUG  */
+static u32 debug = 0;
+
+// END STEP 1
+
+typedef struct library_list {
+
+  u8 *name;
+  u64 addr_start, addr_end;
+
+} library_list_t;
+
+#ifdef __ANDROID__
+u32 __afl_map_size = MAP_SIZE;
+u32 do_exit;
+#else
+__thread u32 __afl_map_size = MAP_SIZE;
+__thread u32 do_exit;
+#endif
+
+static pid_t     pid = 65537;
+static pthread_t __afl_thread;
+static u8        __afl_dummy[MAP_SIZE];
+static u8 *      __afl_area_ptr = __afl_dummy;
+static u8 *      inputfile;  // this will point to argv[1]
+static u32       len;
+
+static library_list_t liblist[MAX_LIB_COUNT];
+static u32            liblist_cnt;
+
+static void sigtrap_handler(int signum, siginfo_t *si, void *context);
+static void fuzz(void);
+
+/* read the library information */
+void read_library_information(void) {
+
+#if defined(__linux__)
+  FILE *f;
+  u8    buf[1024], *b, *m, *e, *n;
+
+  if ((f = fopen("/proc/self/maps", "r")) == NULL)
+    FATAL("cannot open /proc/self/maps");
+
+  if (debug) fprintf(stderr, "Library list:\n");
+  while (fgets(buf, sizeof(buf), f)) {
+
+    if (strstr(buf, " r-x")) {
+
+      if (liblist_cnt >= MAX_LIB_COUNT) {
+
+        WARNF("too many libraries to old, maximum count of %d reached",
+              liblist_cnt);
+        return;
+
+      }
+
+      b = buf;
+      m = index(buf, '-');
+      e = index(buf, ' ');
+      if ((n = rindex(buf, '/')) == NULL) n = rindex(buf, ' ');
+      if (n &&
+          ((*n >= '0' && *n <= '9') || *n == '[' || *n == '{' || *n == '('))
+        n = NULL;
+      else
+        n++;
+      if (b && m && e && n && *n) {
+
+        *m++ = 0;
+        *e = 0;
+        if (n[strlen(n) - 1] == '\n') n[strlen(n) - 1] = 0;
+
+        liblist[liblist_cnt].name = strdup(n);
+        liblist[liblist_cnt].addr_start = strtoull(b, NULL, 16);
+        liblist[liblist_cnt].addr_end = strtoull(m, NULL, 16);
+        if (debug)
+          fprintf(
+              stderr, "%s:%llx (%llx-%llx)\n", liblist[liblist_cnt].name,
+              liblist[liblist_cnt].addr_end - liblist[liblist_cnt].addr_start,
+              liblist[liblist_cnt].addr_start,
+              liblist[liblist_cnt].addr_end - 1);
+        liblist_cnt++;
+
+      }
+
+    }
+
+  }
+
+  if (debug) fprintf(stderr, "\n");
+
+#elif defined(__FreeBSD__)
+  int    mib[] = {CTL_KERN, KERN_PROC, KERN_PROC_VMMAP, getpid()};
+  char * buf, *start, *end;
+  size_t miblen = sizeof(mib) / sizeof(mib[0]);
+  size_t len;
+
+  if (debug) fprintf(stderr, "Library list:\n");
+  if (sysctl(mib, miblen, NULL, &len, NULL, 0) == -1) { return; }
+
+  len = len * 4 / 3;
+
+  buf = mmap(NULL, len, PROT_READ | PROT_WRITE, MAP_SHARED | MAP_ANON, -1, 0);
+  if (buf == MAP_FAILED) { return; }
+
+  if (sysctl(mib, miblen, buf, &len, NULL, 0) == -1) {
+
+    munmap(buf, len);
+    return;
+
+  }
+
+  start = buf;
+  end = buf + len;
+
+  while (start < end) {
+
+    struct kinfo_vmentry *region = (struct kinfo_vmentry *)start;
+    size_t                size = region->kve_structsize;
+
+    if (size == 0) { break; }
+
+    if ((region->kve_protection & KVME_PROT_READ) &&
+        !(region->kve_protection & KVME_PROT_EXEC)) {
+
+      liblist[liblist_cnt].name =
+          region->kve_path[0] != '\0' ? strdup(region->kve_path) : 0;
+      liblist[liblist_cnt].addr_start = region->kve_start;
+      liblist[liblist_cnt].addr_end = region->kve_end;
+
+      if (debug) {
+
+        fprintf(stderr, "%s:%x (%lx-%lx)\n", liblist[liblist_cnt].name,
+                liblist[liblist_cnt].addr_end - liblist[liblist_cnt].addr_start,
+                liblist[liblist_cnt].addr_start,
+                liblist[liblist_cnt].addr_end - 1);
+
+      }
+
+      liblist_cnt++;
+
+    }
+
+    start += size;
+
+  }
+
+#endif
+
+}
+
+library_list_t *find_library(char *name) {
+
+#if defined(__linux__)
+  u32 i;
+
+  for (i = 0; i < liblist_cnt; i++)
+    if (strncmp(liblist[i].name, name, strlen(name)) == 0) return &liblist[i];
+#elif defined(__APPLE__) && defined(__LP64__)
+  kern_return_t         err;
+  static library_list_t lib;
+
+  // get the list of all loaded modules from dyld
+  // the task_info mach API will get the address of the dyld all_image_info
+  // struct for the given task from which we can get the names and load
+  // addresses of all modules
+  task_dyld_info_data_t  task_dyld_info;
+  mach_msg_type_number_t count = TASK_DYLD_INFO_COUNT;
+  err = task_info(mach_task_self(), TASK_DYLD_INFO,
+                  (task_info_t)&task_dyld_info, &count);
+
+  const struct dyld_all_image_infos *all_image_infos =
+      (const struct dyld_all_image_infos *)task_dyld_info.all_image_info_addr;
+  const struct dyld_image_info *image_infos = all_image_infos->infoArray;
+
+  for (size_t i = 0; i < all_image_infos->infoArrayCount; i++) {
+
+    const char *      image_name = image_infos[i].imageFilePath;
+    mach_vm_address_t image_load_address =
+        (mach_vm_address_t)image_infos[i].imageLoadAddress;
+    if (strstr(image_name, name)) {
+
+      lib.name = name;
+      lib.addr_start = (u64)image_load_address;
+      lib.addr_end = 0;
+      return &lib;
+
+    }
+
+  }
+
+#endif
+
+  return NULL;
+
+}
+
+/* for having an easy breakpoint location after loading the shared library */
+// this seems to work for clang too. nice :) requires gcc 4.4+
+#pragma GCC push_options
+#pragma GCC optimize("O0")
+void        breakpoint(void) {
+
+  if (debug) fprintf(stderr, "Breakpoint function \"breakpoint\" reached.\n");
+
+}
+
+#pragma GCC pop_options
+
+/* Error reporting to forkserver controller */
+
+void send_forkserver_error(int error) {
+
+  u32 status;
+  if (!error || error > 0xffff) return;
+  status = (FS_OPT_ERROR | FS_OPT_SET_ERROR(error));
+  if (write(FORKSRV_FD + 1, (char *)&status, 4) != 4) return;
+
+}
+
+/* SHM setup. */
+
+static void __afl_map_shm(void) {
+
+  char *id_str = getenv(SHM_ENV_VAR);
+  char *ptr;
+
+  if ((ptr = getenv("AFL_MAP_SIZE")) != NULL) {
+
+    u32 val = atoi(ptr);
+    if (val > 0) __afl_map_size = val;
+
+  }
+
+  if (__afl_map_size > MAP_SIZE) {
+
+    if (__afl_map_size > FS_OPT_MAX_MAPSIZE) {
+
+      fprintf(stderr,
+              "Error: AFL++ tools *require* to set AFL_MAP_SIZE to %u to "
+              "be able to run this instrumented program!\n",
+              __afl_map_size);
+      if (id_str) {
+
+        send_forkserver_error(FS_ERROR_MAP_SIZE);
+        exit(-1);
+
+      }
+
+    } else {
+
+      fprintf(stderr,
+              "Warning: AFL++ tools will need to set AFL_MAP_SIZE to %u to "
+              "be able to run this instrumented program!\n",
+              __afl_map_size);
+
+    }
+
+  }
+
+  if (id_str) {
+
+#ifdef USEMMAP
+    const char *   shm_file_path = id_str;
+    int            shm_fd = -1;
+    unsigned char *shm_base = NULL;
+
+    /* create the shared memory segment as if it was a file */
+    shm_fd = shm_open(shm_file_path, O_RDWR, 0600);
+    if (shm_fd == -1) {
+
+      fprintf(stderr, "shm_open() failed\n");
+      send_forkserver_error(FS_ERROR_SHM_OPEN);
+      exit(1);
+
+    }
+
+    /* map the shared memory segment to the address space of the process */
+    shm_base =
+        mmap(0, __afl_map_size, PROT_READ | PROT_WRITE, MAP_SHARED, shm_fd, 0);
+
+    if (shm_base == MAP_FAILED) {
+
+      close(shm_fd);
+      shm_fd = -1;
+
+      fprintf(stderr, "mmap() failed\n");
+      send_forkserver_error(FS_ERROR_MMAP);
+      exit(2);
+
+    }
+
+    __afl_area_ptr = shm_base;
+#else
+    u32 shm_id = atoi(id_str);
+
+    __afl_area_ptr = shmat(shm_id, 0, 0);
+
+#endif
+
+    if (__afl_area_ptr == (void *)-1) {
+
+      send_forkserver_error(FS_ERROR_SHMAT);
+      exit(1);
+
+    }
+
+    /* Write something into the bitmap so that the parent doesn't give up */
+
+    __afl_area_ptr[0] = 1;
+
+  }
+
+}
+
+/* Fork server logic. */
+inline static void __afl_start_forkserver(void) {
+
+  u8  tmp[4] = {0, 0, 0, 0};
+  u32 status = 0;
+
+  if (__afl_map_size <= FS_OPT_MAX_MAPSIZE)
+    status |= (FS_OPT_SET_MAPSIZE(__afl_map_size) | FS_OPT_MAPSIZE);
+  if (status) status |= (FS_OPT_ENABLED);
+  memcpy(tmp, &status, 4);
+
+  /* Phone home and tell the parent that we're OK. */
+  if (write(FORKSRV_FD + 1, tmp, 4) != 4) do_exit = 1;
+  // fprintf(stderr, "write0 %d\n", do_exit);
+
+}
+
+inline static u32 __afl_next_testcase(u8 *buf, u32 max_len) {
+
+  s32 status;
+
+  /* Wait for parent by reading from the pipe. Abort if read fails. */
+  if (read(FORKSRV_FD, &status, 4) != 4) do_exit = 1;
+  // fprintf(stderr, "read %d\n", do_exit);
+
+  /* we have a testcase - read it if we read from stdin */
+  if (use_stdin) {
+
+    if ((status = read(0, buf, max_len)) <= 0) exit(-1);
+
+  } else
+
+    status = 1;
+  // fprintf(stderr, "stdin: %d %d\n", use_stdin, status);
+
+  /* report that we are starting the target */
+  if (write(FORKSRV_FD + 1, &pid, 4) != 4) do_exit = 1;
+  // fprintf(stderr, "write1 %d\n", do_exit);
+
+  __afl_area_ptr[0] = 1;  // put something in the map
+
+  return status;
+
+}
+
+inline static void __afl_end_testcase(int status) {
+
+  if (write(FORKSRV_FD + 1, &status, 4) != 4) do_exit = 1;
+  // fprintf(stderr, "write2 %d\n", do_exit);
+  if (do_exit) exit(0);
+
+}
+
+#ifdef __aarch64__
+  #define SHADOW(addr)                                     \
+    ((uint64_t *)(((uintptr_t)addr & 0xfffffffffffffff8) - \
+                  MEMORY_MAP_DECREMENT -                   \
+                  ((uintptr_t)addr & 0x7) * 0x10000000000))
+#else
+  #define SHADOW(addr)                                     \
+    ((uint32_t *)(((uintptr_t)addr & 0xfffffffffffffffc) - \
+                  MEMORY_MAP_DECREMENT -                   \
+                  ((uintptr_t)addr & 0x3) * 0x10000000000))
+#endif
+
+void setup_trap_instrumentation(void) {
+
+  library_list_t *lib_base = NULL;
+  size_t          lib_size = 0;
+  u8 *            lib_addr;
+  char *          line = NULL;
+  size_t          nread, len = 0;
+  char *          filename = getenv("AFL_UNTRACER_FILE");
+  if (!filename) filename = getenv("TRAPFUZZ_FILE");
+  if (!filename) FATAL("AFL_UNTRACER_FILE environment variable not set");
+
+  FILE *patches = fopen(filename, "r");
+  if (!patches) FATAL("Couldn't open AFL_UNTRACER_FILE file %s", filename);
+
+    // Index into the coverage bitmap for the current trap instruction.
+#ifdef __aarch64__
+  uint64_t bitmap_index = 0;
+#else
+  uint32_t bitmap_index = 0;
+#endif
+
+  while ((nread = getline(&line, &len, patches)) != -1) {
+
+    char *end = line + len;
+
+    char *col = strchr(line, ':');
+    if (col) {
+
+      // It's a library:size pair
+      *col++ = 0;
+
+      lib_base = find_library(line);
+      if (!lib_base) FATAL("Library %s does not appear to be loaded", line);
+
+      // we ignore the defined lib_size
+      lib_size = strtoul(col, NULL, 16);
+#if (__linux__)
+      if (lib_size < lib_base->addr_end - lib_base->addr_start)
+        lib_size = lib_base->addr_end - lib_base->addr_start;
+#endif
+      if (lib_size % 0x1000 != 0)
+        WARNF("Invalid library size 0x%zx. Must be multiple of 0x1000",
+              lib_size);
+
+      lib_addr = (u8 *)lib_base->addr_start;
+
+      // Make library code writable.
+      if (mprotect((void *)lib_addr, lib_size,
+                   PROT_READ | PROT_WRITE | PROT_EXEC) != 0)
+        FATAL("Failed to mprotect library %s writable", line);
+
+        // Create shadow memory.
+#ifdef __aarch64__
+      for (int i = 0; i < 8; i++) {
+
+#else
+      for (int i = 0; i < 4; i++) {
+
+#endif
+
+        void *shadow_addr = SHADOW(lib_addr + i);
+        void *shadow = mmap(shadow_addr, lib_size, PROT_READ | PROT_WRITE,
+                            MAP_PRIVATE | MAP_ANON | MAP_FIXED, 0, 0);
+        if (debug)
+          fprintf(stderr, "Shadow: %s %d = %p-%p for %p\n", line, i, shadow,
+                  shadow + lib_size - 1, lib_addr);
+        if (shadow == MAP_FAILED) FATAL("Failed to mmap shadow memory");
+
+      }
+
+      // Done, continue with next line.
+      continue;
+
+    }
+
+    // It's an offset, parse it and do the patching.
+    unsigned long offset = strtoul(line, NULL, 16);
+
+    if (offset > lib_size)
+      FATAL("Invalid offset: 0x%lx. Current library is 0x%zx bytes large",
+            offset, lib_size);
+
+    if (bitmap_index >= __afl_map_size)
+      FATAL("Too many basic blocks to instrument");
+
+#ifdef __arch64__
+    uint64_t
+#else
+    uint32_t
+#endif
+        *shadow = SHADOW(lib_addr + offset);
+    if (*shadow != 0) continue;  // skip duplicates
+
+      // Make lookup entry in shadow memory.
+
+#if ((defined(__APPLE__) && defined(__LP64__)) || defined(__x86_64__) || \
+     defined(__i386__))
+
+    // this is for Intel x64
+
+    uint8_t orig_byte = lib_addr[offset];
+    *shadow = (bitmap_index << 8) | orig_byte;
+    lib_addr[offset] = 0xcc;  // replace instruction with debug trap
+    if (debug)
+      fprintf(stderr,
+              "Patch entry: %p[%x] = %p = %02x -> SHADOW(%p) #%d -> %08x\n",
+              lib_addr, offset, lib_addr + offset, orig_byte, shadow,
+              bitmap_index, *shadow);
+
+#elif defined(__aarch64__)
+
+    // this is for aarch64
+
+    uint32_t *patch_bytes = (uint32_t *)(lib_addr + offset);
+    uint32_t  orig_bytes = *patch_bytes;
+    *shadow = (bitmap_index << 32) | orig_bytes;
+    *patch_bytes = 0xd4200000;  // replace instruction with debug trap
+    if (debug)
+      fprintf(stderr,
+              "Patch entry: %p[%x] = %p = %02x -> SHADOW(%p) #%d -> %016x\n",
+              lib_addr, offset, lib_addr + offset, orig_bytes, shadow,
+              bitmap_index, *shadow);
+
+#else
+    // this will be ARM and AARCH64
+    // for ARM we will need to identify if the code is in thumb or ARM
+  #error "non x86_64/aarch64 not supported yet"
+    //__arm__:
+    // linux thumb: 0xde01
+    // linux arm: 0xe7f001f0
+    //__aarch64__:
+    // linux aarch64: 0xd4200000
+#endif
+
+    bitmap_index++;
+
+  }
+
+  free(line);
+  fclose(patches);
+
+  // Install signal handler for SIGTRAP.
+  struct sigaction s;
+  s.sa_flags = SA_SIGINFO;
+  s.sa_sigaction = sigtrap_handler;
+  sigemptyset(&s.sa_mask);
+  sigaction(SIGTRAP, &s, 0);
+
+  if (debug) fprintf(stderr, "Patched %u locations.\n", bitmap_index);
+  __afl_map_size = bitmap_index;
+  if (__afl_map_size % 8) __afl_map_size = (((__afl_map_size + 7) >> 3) << 3);
+
+}
+
+/* the signal handler for the traps / debugging interrupts
+   No debug output here because this would cost speed      */
+static void sigtrap_handler(int signum, siginfo_t *si, void *context) {
+
+  uint64_t addr;
+  // Must re-execute the instruction, so decrement PC by one instruction.
+  ucontext_t *ctx = (ucontext_t *)context;
+#if defined(__APPLE__) && defined(__LP64__)
+  ctx->uc_mcontext->__ss.__rip -= 1;
+  addr = ctx->uc_mcontext->__ss.__rip;
+#elif defined(__linux__)
+  #if defined(__x86_64__) || defined(__i386__)
+  ctx->uc_mcontext.gregs[REG_RIP] -= 1;
+  addr = ctx->uc_mcontext.gregs[REG_RIP];
+  #elif defined(__aarch64__)
+  ctx->uc_mcontext.pc -= 4;
+  addr = ctx->uc_mcontext.pc;
+  #else
+    #error "Unsupported processor"
+  #endif
+#elif defined(__FreeBSD__) && defined(__LP64__)
+  ctx->uc_mcontext.mc_rip -= 1;
+  addr = ctx->uc_mcontext.mc_rip;
+#else
+  #error "Unsupported platform"
+#endif
+
+  // fprintf(stderr, "TRAP at context addr = %lx, fault addr = %lx\n", addr,
+  // si->si_addr);
+
+  // If the trap didn't come from our instrumentation, then we probably will
+  // just segfault here
+  uint8_t *faultaddr;
+  if (unlikely(si->si_addr))
+    faultaddr = (u8 *)si->si_addr - 1;
+  else
+    faultaddr = (u8 *)addr;
+  // if (debug) fprintf(stderr, "Shadow location: %p\n", SHADOW(faultaddr));
+  uint32_t shadow = *SHADOW(faultaddr);
+  uint8_t  orig_byte = shadow & 0xff;
+  uint32_t index = shadow >> 8;
+
+  // if (debug) fprintf(stderr, "shadow data: %x, orig_byte %02x, index %d\n",
+  // shadow, orig_byte, index);
+
+  // Index zero is invalid so that it is still possible to catch actual trap
+  // instructions in instrumented libraries.
+  if (unlikely(index == 0)) abort();
+
+  // Restore original instruction
+  *faultaddr = orig_byte;
+
+  __afl_area_ptr[index] = 128;
+
+}
+
+/* the MAIN function */
+int main(int argc, char *argv[]) {
+
+  (void)personality(ADDR_NO_RANDOMIZE);  // disable ASLR
+
+  pid = getpid();
+  if (getenv("AFL_DEBUG")) debug = 1;
+
+  /* by default we use stdin, but also a filename can be passed, in this
+     case the input is argv[1] and we have to disable stdin */
+  if (argc > 1) {
+
+    use_stdin = 0;
+    inputfile = argv[1];
+
+  }
+
+  // STEP 2: load the library you want to fuzz and lookup the functions,
+  //         inclusive of the cleanup functions
+  //         NOTE: above the main() you have to define the functions!
+
+  void *dl = dlopen("./libtestinstr.so", RTLD_LAZY);
+  if (!dl) FATAL("could not find target library");
+  o_function = dlsym(dl, "testinstr");
+  if (!o_function) FATAL("could not resolve target function from library");
+  if (debug) fprintf(stderr, "Function address: %p\n", o_function);
+
+  // END STEP 2
+
+  /* setup instrumentation, shared memory and forkserver */
+  breakpoint();
+  read_library_information();
+  setup_trap_instrumentation();
+  __afl_map_shm();
+  __afl_start_forkserver();
+
+  while (1) {
+
+    // instead of fork() we could also use the snapshot lkm or do our own mini
+    // snapshot feature like in https://github.com/marcinguy/fuzzer
+    // -> snapshot.c
+    if ((pid = fork()) == -1) PFATAL("fork failed");
+
+    if (pid) {
+
+      u32 status;
+      if (waitpid(pid, &status, 0) < 0) exit(1);
+      /* report the test case is done and wait for the next */
+      __afl_end_testcase(status);
+
+    } else {
+
+      pid = getpid();
+      while ((len = __afl_next_testcase(buf, sizeof(buf))) > 0) {
+
+        // in this function the fuzz magic happens, this is STEP 3
+        fuzz();
+
+        // we can use _exit which is faster because our target library
+        // was loaded via dlopen and therefore cannot have deconstructors
+        // registered.
+        _exit(0);
+
+      }
+
+    }
+
+  }
+
+  return 0;
+
+}
+
+#ifndef _DEBUG
+inline
+#endif
+    static void
+    fuzz(void) {
+
+  // STEP 3: call the function to fuzz, also the functions you might
+  //         need to call to prepare the function and - important! -
+  //         to clean everything up
+
+  // in this example we use the input file, not stdin!
+  (*o_function)(buf, len);
+
+  // normally you also need to cleanup
+  //(*o_LibFree)(foo);
+
+  // END STEP 3
+
+}
+
diff --git a/utils/afl_untracer/ghidra_get_patchpoints.java b/utils/afl_untracer/ghidra_get_patchpoints.java
new file mode 100644
index 00000000..2a93642b
--- /dev/null
+++ b/utils/afl_untracer/ghidra_get_patchpoints.java
@@ -0,0 +1,84 @@
+/* ###
+ * IP: GHIDRA
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ * 
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ * 
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+// Find patch points for untracer tools (e.g. afl++ utils/afl_untracer)
+//
+//   Copy to ..../Ghidra/Features/Search/ghidra_scripts/
+//   Writes the results to ~/Desktop/patches.txt
+//
+//   This is my very first Ghidra script. I am sure this could be done better.
+//
+//@category Search
+
+import ghidra.app.script.GhidraScript;
+import ghidra.program.model.address.*;
+import ghidra.program.model.block.*;
+import ghidra.program.model.listing.*;
+import ghidra.program.model.symbol.*;
+import ghidra.program.model.mem.*;
+
+import java.io.*;
+
+public class ghidra_get_patchpoints extends GhidraScript {
+
+	@Override
+	public void run() throws Exception {
+
+		long segment_start = 0;
+		Memory memory = currentProgram.getMemory();
+		MultEntSubModel model = new MultEntSubModel(currentProgram);
+		CodeBlockIterator subIter = model.getCodeBlocks(monitor);
+		BufferedWriter out = new BufferedWriter(new FileWriter(System.getProperty("user.home") + File.separator + "Desktop" + File.separator + "patches.txt"));
+
+		while (subIter.hasNext()) {
+
+			CodeBlock multiEntryBlock = subIter.next();
+			SimpleBlockModel basicBlockModel = new SimpleBlockModel(currentProgram);
+			CodeBlockIterator bbIter = basicBlockModel.getCodeBlocksContaining(multiEntryBlock, monitor);
+
+			while (bbIter.hasNext()) {
+
+				CodeBlock basicBlock = bbIter.next();
+
+				if (segment_start == 0) {
+
+					Address firstAddr = basicBlock.getFirstStartAddress();
+					long firstBlockAddr = firstAddr.getAddressableWordOffset();
+					MemoryBlock mb = memory.getBlock(firstAddr);
+					Address startAddr = mb.getStart();
+					Address endAddr = mb.getEnd();
+					segment_start = startAddr.getAddressableWordOffset();
+					if ((firstBlockAddr - segment_start) >= 0x1000)
+					  segment_start += 0x1000;
+					long segment_end = endAddr.getAddressableWordOffset();
+					long segment_size = segment_end - segment_start;
+					if ((segment_size % 0x1000) > 0)
+					  segment_size = (((segment_size / 0x1000) + 1) * 0x1000);
+					out.write(currentProgram.getName() + ":0x" + Long.toHexString(segment_size) + "\n"); 
+					//println("Start: " + Long.toHexString(segment_start));
+					//println("End: " + Long.toHexString(segment_end));
+
+				}
+ 	   		        
+ 	   		        if (basicBlock.getFirstStartAddress().getAddressableWordOffset() - segment_start > 0)
+ 	   		        	out.write("0x" + Long.toHexString(basicBlock.getFirstStartAddress().getAddressableWordOffset() - segment_start) + "\n");
+
+			}
+		}
+
+		out.close();
+
+	}
+}
diff --git a/utils/afl_untracer/ida_get_patchpoints.py b/utils/afl_untracer/ida_get_patchpoints.py
new file mode 100644
index 00000000..43cf6d89
--- /dev/null
+++ b/utils/afl_untracer/ida_get_patchpoints.py
@@ -0,0 +1,62 @@
+#
+# IDAPython script for IDA Pro
+# Slightly modified from https://github.com/googleprojectzero/p0tools/blob/master/TrapFuzz/findPatchPoints.py
+#
+
+import idautils
+import idaapi
+import ida_nalt
+import idc
+
+# See https://www.hex-rays.com/products/ida/support/ida74_idapython_no_bc695_porting_guide.shtml
+
+from os.path import expanduser
+home = expanduser("~")
+
+patchpoints = set()
+
+max_offset = 0
+for seg_ea in idautils.Segments():
+    name = idc.get_segm_name(seg_ea)
+    #print("Segment: " + name)
+    if name != "__text" and name != ".text":
+        continue
+
+    start = idc.get_segm_start(seg_ea)
+    end = idc.get_segm_end(seg_ea)
+    first = 0
+    subtract_addr = 0
+    #print("Start: " + hex(start) + " End: " + hex(end))
+    for func_ea in idautils.Functions(start, end):
+        f = idaapi.get_func(func_ea)
+        if not f:
+            continue
+        for block in idaapi.FlowChart(f):
+            if start <= block.start_ea < end:
+                if first == 0:
+                    if block.start_ea >= 0x1000:
+                        subtract_addr = 0x1000
+                        first = 1
+                        
+                max_offset = max(max_offset, block.start_ea)
+                patchpoints.add(block.start_ea - subtract_addr)
+            #else:
+            #    print("Warning: broken CFG?")
+
+# Round up max_offset to page size
+size = max_offset
+rem = size % 0x1000
+if rem != 0:
+    size += 0x1000 - rem
+
+print("Writing to " + home + "/Desktop/patches.txt")
+
+with open(home + "/Desktop/patches.txt", "w") as f:
+    f.write(ida_nalt.get_root_filename() + ':' + hex(size) + '\n')
+    f.write('\n'.join(map(hex, sorted(patchpoints))))
+    f.write('\n')
+
+print("Done, found {} patchpoints".format(len(patchpoints)))
+
+# For headless script running remove the comment from the next line
+#ida_pro.qexit()
diff --git a/utils/afl_untracer/libtestinstr.c b/utils/afl_untracer/libtestinstr.c
new file mode 100644
index 00000000..96b1cf21
--- /dev/null
+++ b/utils/afl_untracer/libtestinstr.c
@@ -0,0 +1,35 @@
+/*
+   american fuzzy lop++ - a trivial program to test the build
+   --------------------------------------------------------
+   Originally written by Michal Zalewski
+   Copyright 2014 Google Inc. All rights reserved.
+   Copyright 2019-2020 AFLplusplus Project. All rights reserved.
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at:
+     http://www.apache.org/licenses/LICENSE-2.0
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+void testinstr(char *buf, int len) {
+
+  if (len < 1) return;
+  buf[len] = 0;
+
+  // we support three input cases
+  if (buf[0] == '0')
+    printf("Looks like a zero to me!\n");
+  else if (buf[0] == '1')
+    printf("Pretty sure that is a one!\n");
+  else
+    printf("Neither one or zero? How quaint!\n");
+
+}
+
diff --git a/utils/afl_untracer/patches.txt b/utils/afl_untracer/patches.txt
new file mode 100644
index 00000000..7e964249
--- /dev/null
+++ b/utils/afl_untracer/patches.txt
@@ -0,0 +1,34 @@
+libtestinstr.so:0x1000
+0x10
+0x12
+0x20
+0x36
+0x30
+0x40
+0x50
+0x63
+0x6f
+0x78
+0x80
+0xa4
+0xb0
+0xb8
+0x100
+0xc0
+0xc9
+0xd7
+0xe3
+0xe8
+0xf8
+0x105
+0x11a
+0x135
+0x141
+0x143
+0x14e
+0x15a
+0x15c
+0x168
+0x16a
+0x16b
+0x170