fixes

Adding Coverage Estimation using Species Richness Estimators

docs/coverage_estimation.md

@@ -0,0 +1,42 @@
+# Coverage estimation in AFL++
+
+This file describes the coverage estimation of AFL++. For general information about AFL++, see
+[README.md](../README.md).
+
+## Table of Content
+* [Introduction](#1-introduction)
+* [Setup](#2-setup)
+* [Status Screen extension](#3-status-screen-extension)
+
+## 1 Introduction
+The coverage estimation inside AFL++ is based on path coverage. It used STADS (Security Testing As Discovery of Species) to use species richness estimators for coverage estimation.
+The estimated coverage should help developers when to stop a fuzzing campaign.
+The coverage estimation can only be estimated over fuzzable/reachable paths.
+
+Coverage estimation is not tested on multiple fuzzing instances (-M/-S Options). It's also not tested on resuming a fuzz run (AFL_AUTORESUME, -i -).
+
+## 2 Setup
+To use coverage estimation you don't have to change your workflow, just add following environment variables:
+ * Set `AFL_CODE_COVERAGE` during fuzzing (afl-fuzz) to enable coverage estimation.
+ * Consider Setting `AFL_N_FUZZ_SIZE` to something bigger then (1 << 21)(default) to mitigate (Re-)Hash collisions
+ * Consider the use of `AFL_CRASH_ON_HASH_COLLISION` if (slightly) incorrect coverage estimation is worse then a abort
+ * If the coverage estimation should update more often change `COVERAGE_INTERVAL` in [config.h](../config.h) (This requires rebuilding of AFL++)
+
+More information's about these environment variables in [env_variables.md](./env_variables.md).
+
+## 3 Status Screen extension
+The status screen will be extended with following box:
+```
+ +- code coverage information ------------------------+
+ |              coverage : 57.12% - 63.21%            |
+ | collision probability : 1.02%                      |
+ +----------------------------------------------------+
+```
+ * coverage - This is the estimated path coverage. The first number is a lower bound estimate.
+ The second number is a upper bound estimate. It's only possible to estimate the fuzzable/reachable paths.
+ If the coverage is very fast very high you either fuzzing a simple target or don't have a good corpus.
+ Unfortunately there is not enough research done to prove accuracy and precision of these estimators, but they hold in asymptotic behavior and the accuracy and precision of the estimators, go down with more hash collisions (see collision probability).
+ * collision propability - This is a estimate for the probability of hash collisions. If this number gets higher than 25% you should consider increasing `AFL_N_FUZZ_SIZE`. The coverage estimation will lose accuracy (overestimates) when hash collisions occur. You can also chose to ignore this, but then the coverage estimation will suffer.
+ If `AFL_CRASH_ON_HASH_COLLISION` is set afl-fuzz will abort on a detected Hash collision.
+
+This box takes the place of the fuzzing strategy yields, since there are not used when non-deterministic mode is used. Therefore the coverage estimation is not compatible with the deterministic mode (-D).

docs/env_variables.md

@@ -327,6 +327,20 @@ checks or alter some of the more exotic semantics of the tool:
     (`-i in`). This is an important feature to set when resuming a fuzzing
     session.
 
+  - `AFL_CODE_COVERAGE` will enable code coverage estimation. See also 
+    [coverage_estimation.md](./coverage_estimation.md). Related enviroment
+    variables: `AFL_ABUNDANT_CUT_OFF`, `AFL_CRASH_ON_HASH_COLLISION` and
+    `AFL_N_FUZZ_SIZE`
+
+  - Coverage estimation only: `AFL_ABUNDANT_CUT_OFF` describes the cut-off for
+    species richness estimators. Default is 10. The Value should only be changed
+    for research.
+
+  - Coverage estimation only: `AFL_CRASH_ON_HASH_COLLISION` will crash on detected
+    (Re)Hash collisions. If this is not set only a warning is displayed instead of
+    Aborting the Fuzzing campaign. You could also increase `AFL_N_FUZZ_SIZE` to
+    mitigate the chance of a (Re)Hash collision.
+
   - Setting `AFL_CRASH_EXITCODE` sets the exit code AFL++ treats as crash. For
     example, if `AFL_CRASH_EXITCODE='-1'` is set, each input resulting in a `-1`
     return code (i.e. `exit(-1)` got called), will be treated as if a crash had
@@ -450,6 +464,10 @@ checks or alter some of the more exotic semantics of the tool:
     there is a 1 in 201 chance, that one of the dictionary entries will not be
     used directly.
 
+  - Coverage estimation only: `AFL_N_FUZZ_SIZE` sets the amount of Path Hashes that
+    can be stored. Default (1 << 21). Think about increasing this value to mitigate
+    (Re)Hash collisions. Upper Bound is (1 << 64 - 1).
+
   - Setting `AFL_NO_AFFINITY` disables attempts to bind to a specific CPU core
     on Linux systems. This slows things down, but lets you run more instances of
     afl-fuzz than would be prudent (if you really want to).

include/afl-fuzz.h

@@ -130,6 +130,9 @@
 // Little helper to access the ptr to afl->##name_buf - for use in afl_realloc.
 #define AFL_BUF_PARAM(name) ((void **)&afl->name##_buf)
 
+#define LARGE_INDEX(array, index, size, item_size) \
+  array[(u64)((index) / (size / item_size))][(index) % (size / item_size)]
+
 #ifdef WORD_SIZE_64
   #define AFL_RAND_RETURN u64
 #else
@@ -540,7 +543,9 @@ typedef struct afl_state {
       expand_havoc,                /* perform expensive havoc after no find */
       cycle_schedules,                  /* cycle power schedules?           */
       old_seed_selection,               /* use vanilla afl seed selection   */
-      reinit_table;                     /* reinit the queue weight table    */
+      reinit_table,                     /* reinit the queue weight table    */
+      coverage_estimation,              /* Code Coverage Estimation Mode?   */
+      crash_on_hash_collision;          /* Ignore Hash collisions           */
 
   u8 *virgin_bits,                      /* Regions yet untouched by fuzzing */
       *virgin_tmout,                    /* Bits we haven't seen in tmouts   */
@@ -552,8 +557,28 @@ typedef struct afl_state {
 
   u8 *var_bytes;                        /* Bytes that appear to be variable */
 
-#define N_FUZZ_SIZE (1 << 21)
-  u32 *n_fuzz;
+  u64   n_fuzz_size;
+  u32 **n_fuzz;
+
+  double n_fuzz_fill;                   /* Fill level of n_fuzz (0-1)       */
+
+  u32 *path_frequenzy;      /* Frequenzies of Paths for Coverage Estimation */
+  u8   abundant_cut_off;                /* Cut-off Value for estimators     */
+  u64  max_path_number,   /* Number of times most viewed path(s) are viewed */
+      max_path_count,                /* Count of paths wich are most viewed */
+      second_max_path_number,
+      second_max_path_count,      /* Count of paths wich are 2nd most viewed */
+      abundant_paths;                   /* Number of abundant code paths    */
+  u32 coverage_counter,               /* Counter when to calculate coverage */
+      num_detected_collisions;          /* Number of detected Collisions    */
+  double upper_coverage_estimate,       /* Coverage Estimation lower in %   */
+      lower_coverage_estimate;          /* Coverage Estimation upper in %   */
+#if defined COVERAGE_ESTIMATION_LOGGING && COVERAGE_ESTIMATION_LOGGING
+  FILE *coverage_log_file;              /* File to log coverage             */
+  u64   total_paths,                    /* Total Paths saved for logging    */
+      next_save_time;                   /* Time to save Paths again         */
+  u32 **n_fuzz_logged;
+#endif
 
   volatile u8 stop_soon,                /* Ctrl-C pressed?                  */
       clear_screen;                     /* Window resized?                  */
@@ -1138,9 +1163,12 @@ void destroy_extras(afl_state_t *);
 
 /* Stats */
 
-void load_stats_file(afl_state_t *);
-void write_setup_file(afl_state_t *, u32, char **);
-void write_stats_file(afl_state_t *, u32, double, double, double);
+void        load_stats_file(afl_state_t *);
+void        write_setup_file(afl_state_t *, u32, char **);
+void        write_stats_file(afl_state_t *, u32, double, double, double);
+#if defined COVERAGE_ESTIMATION_LOGGING && COVERAGE_ESTIMATION_LOGGING
+void        write_coverage_file(afl_state_t *);
+#endif
 void maybe_update_plot_file(afl_state_t *, u32, double, double);
 void write_queue_stats(afl_state_t *);
 void show_stats(afl_state_t *);

include/config.h

@@ -298,6 +298,15 @@
 #define PLOT_UPDATE_SEC 5
 #define QUEUE_UPDATE_SEC 1800
 
+/* Max Interval for Coverage Estimation in UI Updates - UI Updates is set by
+ * UI_TARGET_HZ */
+
+#define COVERAGE_INTERVAL 10                     /* Roughly every 2 seconds */
+
+/* Write File to log Data for coverage estimation */
+
+#define COVERAGE_ESTIMATION_LOGGING 1
+
 /* Smoothing divisor for CPU load and exec speed stats (1 - no smoothing). */
 
 #define AVG_SMOOTHING 16

include/envs.h

@@ -16,6 +16,7 @@ static char *afl_environment_deprecated[] = {
 
 static char *afl_environment_variables[] = {
 
+    "AFL_ABUNDANT_CUT_OFF",
     "AFL_ALIGNED_ALLOC",
     "AFL_ALLOW_TMP",
     "AFL_ANALYZE_HEX",
@@ -30,11 +31,13 @@ static char *afl_environment_variables[] = {
     "AFL_CMIN_ALLOW_ANY",
     "AFL_CMIN_CRASHES_ONLY",
     "AFL_CMPLOG_ONLY_NEW",
+    "AFL_CODE_COVERAGE",
     "AFL_CODE_END",
     "AFL_CODE_START",
     "AFL_COMPCOV_BINNAME",
     "AFL_COMPCOV_LEVEL",
     "AFL_CRASH_EXITCODE",
+    "AFL_CRASH_ON_HASH_COLLISION",
     "AFL_CRASHING_SEEDS_AS_NEW_CRASH",
     "AFL_CUSTOM_MUTATOR_LIBRARY",
     "AFL_CUSTOM_MUTATOR_ONLY",
@@ -169,6 +172,7 @@ static char *afl_environment_variables[] = {
     "AFL_LLVM_LTO_DONTWRITEID",
     "AFL_LLVM_LTO_SKIPINIT"
     "AFL_LLVM_LTO_STARTID",
+    "AFL_N_FUZZ_SIZE",
     "AFL_NO_ARITH",
     "AFL_NO_AUTODICT",
     "AFL_NO_BUILTIN",

qemu_mode/libqasan/dlmalloc.c

@@ -1,3 +1,4 @@
+
 #include <features.h>
 
 #ifndef __GLIBC__

src/afl-fuzz-bitmap.c

@@ -474,7 +474,8 @@ save_if_interesting(afl_state_t *afl, void *mem, u32 len, u8 fault) {
 
   /* Generating a hash on every input is super expensive. Bad idea and should
      only be used for special schedules */
-  if (unlikely(afl->schedule >= FAST && afl->schedule <= RARE)) {
+  if (likely((afl->schedule >= FAST && afl->schedule <= RARE)) ||
+      unlikely(afl->coverage_estimation)) {
 
     classify_counts(&afl->fsrv);
     classified = 1;
@@ -483,8 +484,91 @@ save_if_interesting(afl_state_t *afl, void *mem, u32 len, u8 fault) {
     cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
 
     /* Saturated increment */
-    if (likely(afl->n_fuzz[cksum % N_FUZZ_SIZE] < 0xFFFFFFFF))
-      afl->n_fuzz[cksum % N_FUZZ_SIZE]++;
+    if (LARGE_INDEX(afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC,
+                    sizeof(u32)) < 0xFFFFFFFF)
+      ++LARGE_INDEX(afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC,
+                    sizeof(u32));
+
+    if (unlikely(afl->coverage_estimation)) {
+
+      if (LARGE_INDEX(afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC,
+                      sizeof(u32)) <= afl->abundant_cut_off + 1U) {
+
+        if ((LARGE_INDEX(afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC,
+                         sizeof(u32)) != 1) &&
+            likely(afl->path_frequenzy[LARGE_INDEX(afl->n_fuzz,
+                                                   cksum % afl->n_fuzz_size,
+                                                   MAX_ALLOC, sizeof(u32)) -
+                                       2] > 0))
+          --afl->path_frequenzy[LARGE_INDEX(afl->n_fuzz,
+                                            cksum % afl->n_fuzz_size, MAX_ALLOC,
+                                            sizeof(u32)) -
+                                2];
+        if (LARGE_INDEX(afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC,
+                        sizeof(u32)) <= afl->abundant_cut_off) {
+
+          if (likely(afl->path_frequenzy[LARGE_INDEX(afl->n_fuzz,
+                                                     cksum % afl->n_fuzz_size,
+                                                     MAX_ALLOC, sizeof(u32)) -
+                                         1] < UINT32_MAX)) {
+
+            ++afl->path_frequenzy[LARGE_INDEX(afl->n_fuzz,
+                                              cksum % afl->n_fuzz_size,
+                                              MAX_ALLOC, sizeof(u32)) -
+                                  1];
+
+          }
+
+        } else {
+
+          ++afl->abundant_paths;
+
+        }
+
+      }
+
+      if (unlikely(afl->max_path_number == 0)) {
+
+        afl->max_path_number = 1;
+        afl->max_path_count = 1;
+
+      } else if (unlikely(LARGE_INDEX(afl->n_fuzz, cksum % afl->n_fuzz_size,
+
+                                      MAX_ALLOC, sizeof(u32)) >=
+
+                          afl->second_max_path_number)) {
+
+        if (LARGE_INDEX(afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC,
+                        sizeof(u32)) == afl->second_max_path_number)
+          ++afl->second_max_path_count;
+        else if (LARGE_INDEX(afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC,
+                             sizeof(u32)) == afl->max_path_number)
+          ++afl->max_path_count;
+        else if (LARGE_INDEX(afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC,
+                             sizeof(u32)) > afl->max_path_number) {
+
+          if (afl->max_path_count > 1) {
+
+            afl->second_max_path_count = afl->max_path_count - 1;
+            afl->second_max_path_number = afl->max_path_number;
+
+          }
+
+          afl->max_path_number = LARGE_INDEX(
+              afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC, sizeof(u32));
+          afl->max_path_count = 1;
+
+        } else /* second max < n_fuzz < max*/ {
+
+          afl->second_max_path_count = 1;
+          afl->second_max_path_number = LARGE_INDEX(
+              afl->n_fuzz, cksum % afl->n_fuzz_size, MAX_ALLOC, sizeof(u32));
+
+        }
+
+      }
+
+    }
 
   }
 
@@ -594,11 +678,43 @@ save_if_interesting(afl_state_t *afl, void *mem, u32 len, u8 fault) {
     /* For AFLFast schedules we update the new queue entry */
     if (likely(cksum)) {
 
-      afl->queue_top->n_fuzz_entry = cksum % N_FUZZ_SIZE;
-      afl->n_fuzz[afl->queue_top->n_fuzz_entry] = 1;
+      afl->queue_top->n_fuzz_entry = cksum % afl->n_fuzz_size;
+      if (unlikely(afl->coverage_estimation)) {
+
+        if (unlikely(LARGE_INDEX(afl->n_fuzz, afl->queue_top->n_fuzz_entry,
+                                 MAX_ALLOC, sizeof(u32)) > 1)) {
+
+          if (afl->crash_on_hash_collision)
+            FATAL(
+                "Hash collision on n_fuzz increase AFL_N_FUZZ_SIZE or ignore "
+                "with removing AFL_CRASH_ON_HASH_COLLISION");
+          else
+            WARNF("Hash collision on n_fuzz increase AFL_N_FUZZ_SIZE! (%lu)",
+                  (unsigned long)++afl->num_detected_collisions);
+          if (LARGE_INDEX(afl->n_fuzz, afl->queue_top->n_fuzz_entry, MAX_ALLOC,
+                          sizeof(u32)) == 0) {
+
+            if (likely(afl->path_frequenzy[0] < UINT32_MAX)) {
+
+              ++afl->path_frequenzy[0];
+
+            }
+
+          }
+
+        }
+
+      }
+
+      LARGE_INDEX(afl->n_fuzz, afl->queue_top->n_fuzz_entry, MAX_ALLOC,
+                  sizeof(u32)) = 1;
 
     }
 
+    /* due to classify counts we have to recalculate the checksum */
+    afl->queue_top->exec_cksum =
+        hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
+
     /* Try to calibrate inline; this also calls update_bitmap_score() when
        successful. */
     res = calibrate_case(afl, afl->queue_top, mem, afl->queue_cycle - 1, 0);

src/afl-fuzz-init.c

@@ -31,6 +31,37 @@
 
 #ifdef HAVE_AFFINITY
 
+/* A helper function for handle_existing_out_dir(), deleting all prefixed
+   files in a directory. */
+
+static u8 delete_files(u8 *path, u8 *prefix) {
+
+  DIR           *d;
+  struct dirent *d_ent;
+
+  d = opendir(path);
+
+  if (!d) { return 0; }
+
+  while ((d_ent = readdir(d))) {
+
+    if (d_ent->d_name[0] != '.' &&
+        (!prefix || !strncmp(d_ent->d_name, prefix, strlen(prefix)))) {
+
+      u8 *fname = alloc_printf("%s/%s", path, d_ent->d_name);
+      if (unlink(fname)) { PFATAL("Unable to delete '%s'", fname); }
+      ck_free(fname);
+
+    }
+
+  }
+
+  closedir(d);
+
+  return !!rmdir(path);
+
+}
+
 /* bind process to a specific cpu. Returns 0 on failure. */
 
 static u8 bind_cpu(afl_state_t *afl, s32 cpuid) {
@@ -1471,7 +1502,17 @@ void pivot_inputs(afl_state_t *afl) {
 
   }
 
-  if (afl->in_place_resume) { nuke_resume_dir(afl); }
+  if (afl->in_place_resume) {
+
+    nuke_resume_dir(afl);
+
+  } else {
+
+    u8 *fn = alloc_printf("%s/path_data", afl->out_dir);
+    (void)delete_files(fn, NULL);
+    ck_free(fn);
+
+  }
 
 }
 
@@ -1560,37 +1601,6 @@ void find_timeout(afl_state_t *afl) {
 
 }
 
-/* A helper function for handle_existing_out_dir(), deleting all prefixed
-   files in a directory. */
-
-static u8 delete_files(u8 *path, u8 *prefix) {
-
-  DIR           *d;
-  struct dirent *d_ent;
-
-  d = opendir(path);
-
-  if (!d) { return 0; }
-
-  while ((d_ent = readdir(d))) {
-
-    if (d_ent->d_name[0] != '.' &&
-        (!prefix || !strncmp(d_ent->d_name, prefix, strlen(prefix)))) {
-
-      u8 *fname = alloc_printf("%s/%s", path, d_ent->d_name);
-      if (unlink(fname)) { PFATAL("Unable to delete '%s'", fname); }
-      ck_free(fname);
-
-    }
-
-  }
-
-  closedir(d);
-
-  return !!rmdir(path);
-
-}
-
 /* Get the number of runnable processes, with some simple smoothing. */
 
 double get_runnable_processes(void) {
@@ -1678,6 +1688,10 @@ void nuke_resume_dir(afl_state_t *afl) {
   if (delete_files(fn, CASE_PREFIX)) { goto dir_cleanup_failed; }
   ck_free(fn);
 
+  fn = alloc_printf("%s/path_data", afl->out_dir);
+  (void)delete_files(fn, NULL);
+  ck_free(fn);
+
   return;
 
 dir_cleanup_failed:
@@ -1841,6 +1855,17 @@ static void handle_existing_out_dir(afl_state_t *afl) {
   if (delete_files(fn, CASE_PREFIX)) { goto dir_cleanup_failed; }
   ck_free(fn);
 
+#if defined COVERAGE_ESTIMATION_LOGGING && COVERAGE_ESTIMATION_LOGGING
+  if (unlikely(afl->coverage_estimation)) {
+
+    fn = alloc_printf("%s/path_data", afl->out_dir);
+    (void)delete_files(fn, NULL);
+    ck_free(fn);
+
+  }
+
+#endif
+
   /* All right, let's do <afl->out_dir>/crashes/id:* and
    * <afl->out_dir>/hangs/id:*. */
 
@@ -1974,6 +1999,14 @@ static void handle_existing_out_dir(afl_state_t *afl) {
   if (unlink(fn) && errno != ENOENT) { goto dir_cleanup_failed; }
   ck_free(fn);
 
+  if (unlikely(afl->coverage_estimation)) {
+
+    fn = alloc_printf("%s/coverage_estimation", afl->out_dir);
+    if (unlink(fn) && errno != ENOENT) { goto dir_cleanup_failed; }
+    ck_free(fn);
+
+  }
+
   fn = alloc_printf("%s/cmdline", afl->out_dir);
   if (unlink(fn) && errno != ENOENT) { goto dir_cleanup_failed; }
   ck_free(fn);
@@ -2182,6 +2215,38 @@ void setup_dirs_fds(afl_state_t *afl) {
         "pending_total, pending_favs, map_size, saved_crashes, "
         "saved_hangs, max_depth, execs_per_sec, total_execs, edges_found\n");
 
+#if defined COVERAGE_ESTIMATION_LOGGING && COVERAGE_ESTIMATION_LOGGING
+    if (unlikely(afl->coverage_estimation)) {
+
+      tmp = alloc_printf("%s/path_data", afl->out_dir);
+      if (mkdir(tmp, 0700)) {
+
+        if (errno != EEXIST)
+          PFATAL("Unable to create '%s'", tmp);
+        else {}
+
+      }
+
+      ck_free(tmp);
+      tmp = alloc_printf("%s/coverage_estimation", afl->out_dir);
+      fd = open(tmp, O_WRONLY | O_CREAT | O_EXCL, DEFAULT_PERMISSION);
+      if (fd < 0) { PFATAL("Unable to create '%s'", tmp); }
+
+      ck_free(tmp);
+      afl->coverage_log_file = fdopen(fd, "w");
+      if (!afl->coverage_log_file) { PFATAL("fdopen() failed"); }
+
+      fprintf(afl->coverage_log_file,
+              "# relative_time, total_paths, abundant_paths, lower_estimate, "
+              "higher_estimate, max_path_number, max_path_count, "
+              "second_max_path_number, "
+              "second_max_path_count, path_frequenzies...\n");
+      fflush(afl->coverage_log_file);
+
+    }
+
+#endif
+
   } else {
 
     int fd = open(tmp, O_WRONLY | O_CREAT, DEFAULT_PERMISSION);

src/afl-fuzz-one.c

@@ -415,7 +415,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
         afl->queue_cur->perf_score, afl->queue_cur->weight,
         afl->queue_cur->favored, afl->queue_cur->was_fuzzed,
         afl->queue_cur->exec_us,
-        likely(afl->n_fuzz) ? afl->n_fuzz[afl->queue_cur->n_fuzz_entry] : 0,
+        likely(afl->n_fuzz)
+            ? LARGE_INDEX(afl->n_fuzz, afl->queue_cur->n_fuzz_entry, MAX_ALLOC,
+                          sizeof(u32))
+            : 0,
         afl->queue_cur->bitmap_size, afl->queue_cur->is_ascii, time_tmp);
     fflush(stdout);
 

src/afl-fuzz-queue.c

@@ -68,7 +68,8 @@ double compute_weight(afl_state_t *afl, struct queue_entry *q,
 
   if (likely(afl->schedule >= FAST && afl->schedule <= RARE)) {
 
-    u32 hits = afl->n_fuzz[q->n_fuzz_entry];
+    u32 hits =
+        LARGE_INDEX(afl->n_fuzz, q->n_fuzz_entry, MAX_ALLOC, sizeof(u32));
     if (likely(hits)) { weight /= (log10(hits) + 1); }
 
   }
@@ -704,7 +705,8 @@ void update_bitmap_score(afl_state_t *afl, struct queue_entry *q) {
   if (unlikely(afl->schedule >= FAST && afl->schedule < RARE))
     fuzz_p2 = 0;  // Skip the fuzz_p2 comparison
   else if (unlikely(afl->schedule == RARE))
-    fuzz_p2 = next_pow2(afl->n_fuzz[q->n_fuzz_entry]);
+    fuzz_p2 = next_pow2(
+        LARGE_INDEX(afl->n_fuzz, q->n_fuzz_entry, MAX_ALLOC, sizeof(u32)));
   else
     fuzz_p2 = q->fuzz_level;
 
@@ -730,8 +732,9 @@ void update_bitmap_score(afl_state_t *afl, struct queue_entry *q) {
         u64 top_rated_fav_factor;
         u64 top_rated_fuzz_p2;
         if (unlikely(afl->schedule >= FAST && afl->schedule <= RARE))
-          top_rated_fuzz_p2 =
-              next_pow2(afl->n_fuzz[afl->top_rated[i]->n_fuzz_entry]);
+          top_rated_fuzz_p2 = next_pow2(
+              LARGE_INDEX(afl->n_fuzz, afl->top_rated[i]->n_fuzz_entry,
+                          MAX_ALLOC, sizeof(u32)));
         else
           top_rated_fuzz_p2 = afl->top_rated[i]->fuzz_level;
 
@@ -1032,7 +1035,9 @@ u32 calculate_score(afl_state_t *afl, struct queue_entry *q) {
 
         if (likely(!afl->queue_buf[i]->disabled)) {
 
-          fuzz_mu += log2(afl->n_fuzz[afl->queue_buf[i]->n_fuzz_entry]);
+          fuzz_mu +=
+              log2(LARGE_INDEX(afl->n_fuzz, afl->queue_buf[i]->n_fuzz_entry,
+                               MAX_ALLOC, sizeof(u32)));
           n_items++;
 
         }
@@ -1043,7 +1048,8 @@ u32 calculate_score(afl_state_t *afl, struct queue_entry *q) {
 
       fuzz_mu = fuzz_mu / n_items;
 
-      if (log2(afl->n_fuzz[q->n_fuzz_entry]) > fuzz_mu) {
+      if (log2(LARGE_INDEX(afl->n_fuzz, q->n_fuzz_entry, MAX_ALLOC,
+                           sizeof(u32)) > fuzz_mu)) {
 
         /* Never skip favourites */
         if (!q->favored) factor = 0;
@@ -1058,7 +1064,8 @@ u32 calculate_score(afl_state_t *afl, struct queue_entry *q) {
       // Don't modify unfuzzed seeds
       if (!q->fuzz_level) break;
 
-      switch ((u32)log2(afl->n_fuzz[q->n_fuzz_entry])) {
+      switch ((u32)log2(
+          LARGE_INDEX(afl->n_fuzz, q->n_fuzz_entry, MAX_ALLOC, sizeof(u32)))) {
 
         case 0 ... 1:
           factor = 4;
@@ -1097,7 +1104,9 @@ u32 calculate_score(afl_state_t *afl, struct queue_entry *q) {
       // Don't modify perf_score for unfuzzed seeds
       if (!q->fuzz_level) break;
 
-      factor = q->fuzz_level / (afl->n_fuzz[q->n_fuzz_entry] + 1);
+      factor = q->fuzz_level / (LARGE_INDEX(afl->n_fuzz, q->n_fuzz_entry,
+                                            MAX_ALLOC, sizeof(u32)) +
+                                1);
       break;
 
     case QUAD:
@@ -1105,7 +1114,9 @@ u32 calculate_score(afl_state_t *afl, struct queue_entry *q) {
       if (!q->fuzz_level) break;
 
       factor =
-          q->fuzz_level * q->fuzz_level / (afl->n_fuzz[q->n_fuzz_entry] + 1);
+          q->fuzz_level * q->fuzz_level /
+          (LARGE_INDEX(afl->n_fuzz, q->n_fuzz_entry, MAX_ALLOC, sizeof(u32)) +
+           1);
       break;
 
     case MMOPT:
@@ -1130,8 +1141,10 @@ u32 calculate_score(afl_state_t *afl, struct queue_entry *q) {
       perf_score += (q->tc_ref * 10);
       // the more often fuzz result paths are equal to this queue entry,
       // reduce its value
-      perf_score *= (1 - (double)((double)afl->n_fuzz[q->n_fuzz_entry] /
-                                  (double)afl->fsrv.total_execs));
+      perf_score *=
+          (1 - (double)((double)LARGE_INDEX(afl->n_fuzz, q->n_fuzz_entry,
+                                            MAX_ALLOC, sizeof(u32)) /
+                        (double)afl->fsrv.total_execs));
 
       break;
 

src/afl-fuzz-run.c

@@ -993,7 +993,6 @@ u8 trim_case(afl_state_t *afl, struct queue_entry *q, u8 *in_buf) {
       }
 
       /* Since this can be slow, update the screen every now and then. */
-
       if (!(trim_exec++ % afl->stats_update_freq)) { show_stats(afl); }
       ++afl->stage_cur;
 

src/afl-fuzz-stats.c

@@ -286,7 +286,6 @@ void write_stats_file(afl_state_t *afl, u32 t_bytes, double bitmap_cvg,
 #ifndef __HAIKU__
   if (getrusage(RUSAGE_CHILDREN, &rus)) { rus.ru_maxrss = 0; }
 #endif
-
   fprintf(
       f,
       "start_time        : %llu\n"
@@ -328,6 +327,7 @@ void write_stats_file(afl_state_t *afl, u32 t_bytes, double bitmap_cvg,
       "testcache_size    : %llu\n"
       "testcache_count   : %u\n"
       "testcache_evict   : %u\n"
+      "hash_collisions   : %lu\n"
       "afl_banner        : %s\n"
       "afl_version       : " VERSION
       "\n"
@@ -368,7 +368,8 @@ void write_stats_file(afl_state_t *afl, u32 t_bytes, double bitmap_cvg,
 #endif
       t_bytes, afl->fsrv.real_map_size, afl->var_byte_count, afl->expand_havoc,
       afl->a_extras_cnt, afl->q_testcase_cache_size,
-      afl->q_testcase_cache_count, afl->q_testcase_evictions, afl->use_banner,
+      afl->q_testcase_cache_count, afl->q_testcase_evictions,
+      (unsigned long)afl->num_detected_collisions, afl->use_banner,
       afl->unicorn_mode ? "unicorn" : "", afl->fsrv.qemu_mode ? "qemu " : "",
       afl->fsrv.cs_mode ? "coresight" : "",
       afl->non_instrumented_mode ? " non_instrumented " : "",
@@ -448,6 +449,62 @@ void write_queue_stats(afl_state_t *afl) {
 
 #endif
 
+/* Write coverage file */
+#if defined COVERAGE_ESTIMATION_LOGGING && COVERAGE_ESTIMATION_LOGGING
+void        write_coverage_file(afl_state_t *afl) {
+
+  char *tmp = alloc_printf("%s/path_data/time:%llu", afl->out_dir,
+                                  (unsigned long long)afl->next_save_time / 1000);
+  s32   fd = open(tmp, O_WRONLY | O_CREAT | O_EXCL, DEFAULT_PERMISSION);
+  if (unlikely(fd < 0)) { PFATAL("Unable to create '%s'", tmp); }
+  FILE *current_file = fdopen(fd, "w");
+  // Write file header
+  fprintf(current_file, "# path hash, number of times path is fuzzed\n");
+  for (u64 i = 0; i < afl->n_fuzz_size; i++) {
+
+    if (LARGE_INDEX(afl->n_fuzz, i, MAX_ALLOC, sizeof(u32)) !=
+        LARGE_INDEX(afl->n_fuzz_logged, i, MAX_ALLOC, sizeof(u32))) {
+
+      fprintf(
+          current_file, "%llu,%lu\n", (unsigned long long)i,
+          (unsigned long)LARGE_INDEX(afl->n_fuzz, i, MAX_ALLOC, sizeof(u32)));
+      LARGE_INDEX(afl->n_fuzz_logged, i, MAX_ALLOC, sizeof(u32)) =
+          LARGE_INDEX(afl->n_fuzz, i, MAX_ALLOC, sizeof(u32));
+
+    }
+
+  }
+
+  fflush(current_file);
+  fclose(current_file);
+  if (afl->next_save_time < 1000 * 60 * 15) {
+
+    // Save every 1 min
+    afl->next_save_time += 1000 * 60;
+
+  } else if (afl->next_save_time < 1000 * 60 * 60 * 6 /* 6h */) {
+
+    // Save every 15 min
+    afl->next_save_time += 1000 * 60 * 15;
+
+  } else if (afl->next_save_time < 1000 * 60 * 60 * 24 * 2 /* 2d */) {
+
+    // Save every 6h
+    afl->next_save_time += 1000 * 60 * 60 * 6;
+
+  } else {
+
+    // Save every 12h
+    afl->next_save_time += 1000 * 60 * 60 * 12;
+
+  }
+
+  return;
+
+}
+
+#endif
+
 /* Update the plot file if there is a reason to. */
 
 void maybe_update_plot_file(afl_state_t *afl, u32 t_bytes, double bitmap_cvg,
@@ -483,10 +540,9 @@ void maybe_update_plot_file(afl_state_t *afl, u32 t_bytes, double bitmap_cvg,
 
   /* Fields in the file:
 
-     relative_time, afl->cycles_done, cur_item, corpus_count, corpus_not_fuzzed,
-     favored_not_fuzzed, saved_crashes, saved_hangs, max_depth,
-     execs_per_sec, edges_found */
-
+      relative_time, afl->cycles_done, cur_item, corpus_count,
+      corpus_not_fuzzed, favored_not_fuzzed, saved_crashes, saved_hangs,
+      max_depth, execs_per_sec, edges_found */
   fprintf(afl->fsrv.plot_file,
           "%llu, %llu, %u, %u, %u, %u, %0.02f%%, %llu, %llu, %u, %0.02f, %llu, "
           "%u\n",
@@ -498,6 +554,37 @@ void maybe_update_plot_file(afl_state_t *afl, u32 t_bytes, double bitmap_cvg,
 
   fflush(afl->fsrv.plot_file);
 
+#if defined COVERAGE_ESTIMATION_LOGGING && COVERAGE_ESTIMATION_LOGGING
+  if (unlikely(afl->coverage_estimation)) {
+
+    /* Update log file for coverage estimation */
+    /*Fields in the file:
+      relative_time, total_paths, abundant_paths, lower_estimate,
+      higher_estimate, max_path_number, max_path_count, second_max_path_number
+      second_max_path_count, path_frequenzies... */
+    fprintf(afl->coverage_log_file,
+            "%llu, %llu, %llu, %0.02f%%, %0.02f%%, %llu, %llu, %llu, %llu",
+            ((afl->prev_run_time + get_cur_time() - afl->start_time) / 1000),
+            afl->total_paths, afl->abundant_paths,
+            afl->lower_coverage_estimate * 100,
+            afl->upper_coverage_estimate * 100, afl->max_path_number,
+            afl->max_path_count, afl->second_max_path_number,
+            afl->second_max_path_count);
+
+    for (u8 i = 0; i < afl->abundant_cut_off; i++) {
+
+      fprintf(afl->coverage_log_file, ", %u", afl->path_frequenzy[i]);
+
+    }
+
+    fprintf(afl->coverage_log_file, "\n");
+
+    fflush(afl->coverage_log_file);
+
+  }
+
+#endif
+
 }
 
 /* Check terminal dimensions after resize. */
@@ -511,6 +598,7 @@ static void check_term_size(afl_state_t *afl) {
   if (ioctl(1, TIOCGWINSZ, &ws)) { return; }
 
   if (ws.ws_row == 0 || ws.ws_col == 0) { return; }
+
   if (ws.ws_row < 24 || ws.ws_col < 79) { afl->term_too_small = 1; }
 
 }
@@ -520,6 +608,123 @@ static void check_term_size(afl_state_t *afl) {
 
 void show_stats(afl_state_t *afl) {
 
+  if (unlikely(afl->coverage_estimation)) {
+
+#if defined COVERAGE_ESTIMATION_LOGGING && COVERAGE_ESTIMATION_LOGGING
+
+    u64 cur_time = get_cur_time();
+    if (unlikely(cur_time - afl->start_time > afl->next_save_time)) {
+
+      write_coverage_file(afl);
+
+    }
+
+#endif
+    afl->coverage_counter++;
+    if (afl->coverage_counter >= COVERAGE_INTERVAL &&
+        afl->max_path_number >= afl->abundant_cut_off) {
+
+      afl->coverage_counter = 0;
+      u64 n_rare = 0, s_rare = 0, sum_i = 0;
+      for (u8 i = 0; i < afl->abundant_cut_off; i++) {
+
+        s_rare += afl->path_frequenzy[i];
+        n_rare += afl->path_frequenzy[i] * (u64)(i + 1);
+        sum_i += afl->path_frequenzy[i] * (u64)i * (i + 1);
+
+      }
+
+      u64 s_total = s_rare + afl->abundant_paths;
+#if defined COVERAGE_ESTIMATION_LOGGING && COVERAGE_ESTIMATION_LOGGING
+      afl->total_paths = s_total;
+#endif
+      afl->n_fuzz_fill = (double)s_total / afl->n_fuzz_size;
+      if (likely(n_rare)) {
+
+        u64 n_abundant = afl->fsrv.total_execs - n_rare;
+        if (unlikely(n_abundant > afl->fsrv.total_execs)) /* Check underflow*/ {
+
+          FATAL(
+              "Total number of Paths or Executions is less than rare"
+              "Executions");
+
+        }
+
+        double c_rare = 1 - (double)afl->path_frequenzy[0] / n_rare;
+        if (likely(n_rare != 10)) {
+
+          double s_lower_estimate = 0;
+          if (c_rare == 0) /* all singleton */ {
+
+            s_lower_estimate =
+                (((double)afl->fsrv.total_execs - 1) / afl->fsrv.total_execs *
+                 afl->path_frequenzy[0] * (afl->path_frequenzy[0] - 1) / 2.0);
+
+          } else {
+
+            double variation_rare =
+                (s_rare / c_rare) * ((double)sum_i / (n_rare * (n_rare - 10))) -
+                1;
+            if (variation_rare < 0) variation_rare = 0;
+            s_lower_estimate = afl->abundant_paths + s_rare / c_rare +
+                               afl->path_frequenzy[0] / c_rare * variation_rare;
+
+          }
+
+          afl->upper_coverage_estimate =
+              (double)s_total / (s_lower_estimate + s_total);
+          double pi_zero =
+              (double)s_lower_estimate / (s_lower_estimate + s_total);
+          if (pi_zero < 0.5) {
+
+            afl->lower_coverage_estimate =
+                s_total / ((double)2 * s_total - afl->max_path_count);
+
+          } else {
+
+            double p_max_minus_one =
+                       (double)(s_total - afl->max_path_count) / s_total,
+                   p_max_minus_two = (double)(s_total - afl->max_path_count -
+                                              afl->second_max_path_count) /
+                                     s_total;
+            double pi_max_minus_one = pi_zero + (1 - pi_zero) * p_max_minus_one,
+                   pi_max_minus_two = pi_zero + (1 - pi_zero) * p_max_minus_two;
+            double normalisation_factor = 0;
+            if (p_max_minus_one == p_max_minus_two) {
+
+              normalisation_factor = (1 - p_max_minus_two);
+
+            } else {
+
+              normalisation_factor =
+                  (1 - p_max_minus_two) *
+                  ((p_max_minus_one - p_max_minus_two) /
+                   (p_max_minus_one -
+                    p_max_minus_two * pi_max_minus_two / pi_max_minus_one));
+
+            }
+
+            double estimated_paths =
+                s_total /
+                (1 - normalisation_factor / (1 - normalisation_factor) *
+                         p_max_minus_two / (1 - p_max_minus_two));
+            afl->lower_coverage_estimate = (double)s_total / estimated_paths;
+
+          }
+
+        }
+
+      } else /*n_rare = 0*/ {
+
+        afl->lower_coverage_estimate = 1;
+        afl->upper_coverage_estimate = 1;
+
+      }
+
+    }
+
+  }
+
   if (afl->pizza_is_served) {
 
     show_stats_pizza(afl);
@@ -1044,9 +1249,17 @@ void show_stats_normal(afl_state_t *afl) {
   SAYF(bSTG bV bSTOP "  total tmouts : " cRST "%-20s" bSTG bV "\n", tmp);
 
   /* Aaaalmost there... hold on! */
+  if (likely(!afl->coverage_estimation)) {
 
-  SAYF(bVR bH cCYA bSTOP " fuzzing strategy yields " bSTG bH10 bH2 bHT bH10 bH2
-           bH bHB bH bSTOP cCYA " item geometry " bSTG bH5 bH2 bVL "\n");
+    SAYF(bVR bH cCYA bSTOP " fuzzing strategy yields " bSTG bH10 bH2 bHT bH10
+             bH2 bH bHB bH bSTOP cCYA " item geometry " bSTG bH5 bH2 bVL "\n");
+
+  } else {
+
+    SAYF(bVR bH cCYA bSTOP " code coverage information " bSTG bH10 bHT bH10 bH2
+             bH bHB bH bSTOP cCYA " item geometry " bSTG bH5 bH2 bVL "\n");
+
+  }
 
   if (unlikely(afl->custom_only)) {
 
@@ -1068,9 +1281,26 @@ void show_stats_normal(afl_state_t *afl) {
 
   }
 
-  SAYF(bV bSTOP "   bit flips : " cRST "%-36s " bSTG bV bSTOP
-                "    levels : " cRST "%-10s" bSTG       bV "\n",
-       tmp, u_stringify_int(IB(0), afl->max_depth));
+  if (likely(!afl->coverage_estimation)) {
+
+    SAYF(bV bSTOP "   bit flips : " cRST "%-36s " bSTG bV bSTOP
+                  "    levels : " cRST "%-10s" bSTG       bV "\n",
+         tmp, u_stringify_int(IB(0), afl->max_depth));
+
+  } else {
+
+    if (afl->upper_coverage_estimate ||
+        afl->lower_coverage_estimate) /* If both are 0 they are not yet
+                                         calculated */
+      sprintf(tmp, "%6.2f%% - %6.2f%%", afl->lower_coverage_estimate * 100,
+              afl->upper_coverage_estimate * 100);
+    else
+      sprintf(tmp, "not yet calculated!");
+    SAYF(bV bSTOP "              coverage : " cRST "%-27s" bSTG bV bSTOP
+                  "    levels : " cRST "%-10s" bSTG                bV "\n",
+         tmp, u_stringify_int(IB(0), afl->max_depth));
+
+  }
 
   if (unlikely(!afl->skip_deterministic)) {
 
@@ -1084,9 +1314,38 @@ void show_stats_normal(afl_state_t *afl) {
 
   }
 
-  SAYF(bV bSTOP "  byte flips : " cRST "%-36s " bSTG bV bSTOP
-                "   pending : " cRST "%-10s" bSTG       bV "\n",
-       tmp, u_stringify_int(IB(0), afl->pending_not_fuzzed));
+  if (likely(!afl->coverage_estimation)) {
+
+    SAYF(bV bSTOP "  byte flips : " cRST "%-36s " bSTG bV bSTOP
+                  "   pending : " cRST "%-10s" bSTG       bV "\n",
+         tmp, u_stringify_int(IB(0), afl->pending_not_fuzzed));
+
+  } else {
+
+    sprintf(tmp, "%.2f%%", afl->n_fuzz_fill * 100);
+    SAYF(bV bSTOP " collision probability : ");
+    if (afl->n_fuzz_fill < 0.05) {
+
+      SAYF(cRST);
+
+    } else if (afl->n_fuzz_fill < 0.25) {
+
+      SAYF(bSTG);
+
+    } else if (afl->n_fuzz_fill < 0.5) {
+
+      SAYF(cYEL);
+
+    } else {
+
+      SAYF(cLRD);
+
+    }
+
+    SAYF("%-27s" bSTG bV bSTOP "   pending : " cRST "%-10s" bSTG bV "\n", tmp,
+         u_stringify_int(IB(0), afl->pending_not_fuzzed));
+
+  }
 
   if (unlikely(!afl->skip_deterministic)) {
 
@@ -1100,9 +1359,30 @@ void show_stats_normal(afl_state_t *afl) {
 
   }
 
-  SAYF(bV bSTOP " arithmetics : " cRST "%-36s " bSTG bV bSTOP
-                "  pend fav : " cRST "%-10s" bSTG       bV "\n",
-       tmp, u_stringify_int(IB(0), afl->pending_favored));
+  if (likely(!afl->coverage_estimation)) {
+
+    SAYF(bV bSTOP " arithmetics : " cRST "%-36s " bSTG bV bSTOP
+                  "  pend fav : " cRST "%-10s" bSTG       bV "\n",
+         tmp, u_stringify_int(IB(0), afl->pending_favored));
+
+  } else {
+
+    if (unlikely(afl->custom_only)) {
+
+      strcpy(tmp, "disabled (custom-mutator-only mode)");
+
+    } else {
+
+      strcpy(tmp, "disabled (default, enable with -D)");
+
+    }
+
+    SAYF(bVR bH cCYA                                      bSTOP
+         " fuzzing strategy yields " bSTG bH20 bH5 bH bVL bSTOP
+         "  pend fav : " cRST "%-10s" bSTG                bV "\n",
+         u_stringify_int(IB(0), afl->pending_favored));
+
+  }
 
   if (unlikely(!afl->skip_deterministic)) {
 
@@ -2175,6 +2455,19 @@ void show_stats_pizza(afl_state_t *afl) {
 
   }
 
+  if (unlikely(afl->coverage_estimation)) {
+
+    SAYF(SET_G1 "\n" bSTG bVR bH cCYA                                bSTOP
+                " code coverage information " bSTG bH20 bH20 bH5 bH2 bVL "\n");
+    if (afl->upper_coverage_estimate && afl->lower_coverage_estimate)
+      sprintf(tmp, "%6.2f%% - %6.2f%%", afl->lower_coverage_estimate * 100,
+              afl->upper_coverage_estimate * 100);
+    else
+      sprintf(tmp, "oven not hot enough!");
+    SAYF(bV bSTOP " coverage : " cRST "%-63s" bSTG bV, tmp);
+
+  }
+
   /* Last line */
   SAYF(SET_G1 "\n" bSTG bLB bH30 bH20 bH2 bH20 bH2 bH bRB bSTOP cRST RESET_G1);
 

src/afl-fuzz.c

@@ -157,8 +157,6 @@ static void usage(u8 *argv0, int more_help) {
       "  -Q            - use binary-only instrumentation (QEMU mode)\n"
       "  -U            - use unicorn-based instrumentation (Unicorn mode)\n"
       "  -W            - use qemu-based instrumentation with Wine (Wine mode)\n"
-#endif
-#if defined(__linux__)
       "  -X            - use VM fuzzing (NYX mode - standalone mode)\n"
       "  -Y            - use VM fuzzing (NYX mode - multiple instances mode)\n"
 #endif
@@ -251,11 +249,13 @@ static void usage(u8 *argv0, int more_help) {
       "              (must contain abort_on_error=1 and symbolize=0)\n"
       "MSAN_OPTIONS: custom settings for MSAN\n"
       "              (must contain exitcode="STRINGIFY(MSAN_ERROR)" and symbolize=0)\n"
+      "AFL_ABUNDANT_CUT_OFF: cut of for code coverage estimatiors (default 10)\n"
       "AFL_AUTORESUME: resume fuzzing if directory specified by -o already exists\n"
       "AFL_BENCH_JUST_ONE: run the target just once\n"
       "AFL_BENCH_UNTIL_CRASH: exit soon when the first crashing input has been found\n"
       "AFL_CMPLOG_ONLY_NEW: do not run cmplog on initial testcases (good for resumes!)\n"
       "AFL_CRASH_EXITCODE: optional child exit code to be interpreted as crash\n"
+      "AFL_CODE_COVERAGE: enable code coverage estimators\n"
       "AFL_CUSTOM_MUTATOR_LIBRARY: lib with afl_custom_fuzz() to mutate inputs\n"
       "AFL_CUSTOM_MUTATOR_ONLY: avoid AFL++'s internal mutators\n"
       "AFL_CYCLE_SCHEDULES: after completing a cycle, switch to a different -p schedule\n"
@@ -1542,6 +1542,22 @@ int main(int argc, char **argv_orig, char **envp) {
   }
 
   ACTF("Getting to work...");
+  {
+
+    char *n_fuzz_size = get_afl_env("AFL_N_FUZZ_SIZE");
+    char *end = NULL;
+    if (n_fuzz_size == NULL ||
+        (afl->n_fuzz_size = strtoull(n_fuzz_size, &end, 0)) == 0) {
+
+      ACTF("Using default n_fuzz_size of 1 << 21");
+      afl->n_fuzz_size = (1 << 21);
+
+    }
+
+    if (get_afl_env("AFL_CRASH_ON_HASH_COLLISION"))
+      afl->crash_on_hash_collision = 1;
+
+  }
 
   switch (afl->schedule) {
 
@@ -1583,7 +1599,24 @@ int main(int argc, char **argv_orig, char **envp) {
   /* Dynamically allocate memory for AFLFast schedules */
   if (afl->schedule >= FAST && afl->schedule <= RARE) {
 
-    afl->n_fuzz = ck_alloc(N_FUZZ_SIZE * sizeof(u32));
+    afl->n_fuzz = ck_alloc((afl->n_fuzz_size * sizeof(u32) /
+                                (MAX_ALLOC / sizeof(u32) * sizeof(u32)) +
+                            1) *
+                           sizeof(u32 *));
+    if (afl->n_fuzz_size * sizeof(u32) %
+        (MAX_ALLOC / sizeof(u32) * sizeof(u32)))
+      afl->n_fuzz[afl->n_fuzz_size * sizeof(u32) /
+                  (MAX_ALLOC / sizeof(u32) * sizeof(u32))] =
+          ck_alloc(afl->n_fuzz_size * sizeof(u32) %
+                   (MAX_ALLOC / sizeof(u32) * sizeof(u32)));
+    for (u32 i = 0; i < afl->n_fuzz_size * sizeof(u32) /
+                            (MAX_ALLOC / sizeof(u32) * sizeof(u32));
+         i++) {
+
+      ;
+      afl->n_fuzz[i] = ck_alloc(MAX_ALLOC);
+
+    }
 
   }
 
@@ -1592,6 +1625,82 @@ int main(int argc, char **argv_orig, char **envp) {
   if (get_afl_env("AFL_NO_ARITH")) { afl->no_arith = 1; }
   if (get_afl_env("AFL_SHUFFLE_QUEUE")) { afl->shuffle_queue = 1; }
   if (get_afl_env("AFL_EXPAND_HAVOC_NOW")) { afl->expand_havoc = 1; }
+  if (get_afl_env("AFL_CODE_COVERAGE")) {
+
+    if (afl->skip_deterministic == 0) {
+
+      FATAL("AFL_CODE_COVERAGE is not compatible with -D");
+
+    }
+
+    if (afl->in_place_resume) {
+
+      FATAL("AFL_CODE_COVERAGE is not compatible with '-i -'/AFL_AUTORESUME");
+
+    }
+
+    afl->coverage_estimation = 1;
+    char *cut_off = get_afl_env("AFL_ABUNDANT_CUT_OFF");
+    if (cut_off == NULL || (afl->abundant_cut_off = atoi(cut_off)) <= 0) {
+
+      WARNF(
+          "Code Coverage is set but AFL_ABUNDANT_CUT_OFF is not valid default "
+          "10 is selected");
+      afl->abundant_cut_off = 10;
+
+    };
+
+    afl->path_frequenzy = ck_alloc((afl->abundant_cut_off) * sizeof(u32));
+    if (afl->n_fuzz == NULL) {
+
+      afl->n_fuzz = ck_alloc((afl->n_fuzz_size * sizeof(u32) /
+                                  (MAX_ALLOC / sizeof(u32) * sizeof(u32)) +
+                              1) *
+                             sizeof(u32 *));
+      if (afl->n_fuzz_size * sizeof(u32) %
+          (MAX_ALLOC / sizeof(u32) * sizeof(u32)))
+        afl->n_fuzz[afl->n_fuzz_size * sizeof(u32) /
+                    (MAX_ALLOC / sizeof(u32) * sizeof(u32))] =
+            ck_alloc(afl->n_fuzz_size * sizeof(u32) %
+                     (MAX_ALLOC / sizeof(u32) * sizeof(u32)));
+      for (u32 i = 0; i < afl->n_fuzz_size * sizeof(u32) /
+                              (MAX_ALLOC / sizeof(u32) * sizeof(u32));
+           i++) {
+
+        afl->n_fuzz[i] = ck_alloc(MAX_ALLOC);
+
+      }
+
+    }
+
+  }
+
+  #if defined COVERAGE_ESTIMATION_LOGGING && COVERAGE_ESTIMATION_LOGGING
+  afl->n_fuzz_logged = ck_alloc((afl->n_fuzz_size * sizeof(u32) /
+                                     (MAX_ALLOC / sizeof(u32) * sizeof(u32)) +
+                                 1) *
+                                sizeof(u32 *));
+  if (afl->n_fuzz_size * sizeof(u32) % (MAX_ALLOC / sizeof(u32) * sizeof(u32)))
+    afl->n_fuzz_logged[afl->n_fuzz_size * sizeof(u32) /
+                       (MAX_ALLOC / sizeof(u32) * sizeof(u32))] =
+        ck_alloc(afl->n_fuzz_size * sizeof(u32) %
+                 (MAX_ALLOC / sizeof(u32) * sizeof(u32)));
+  for (u32 i = 0; i < afl->n_fuzz_size * sizeof(u32) /
+                          (MAX_ALLOC / sizeof(u32) * sizeof(u32));
+       i++) {
+
+    ;
+    afl->n_fuzz_logged[i] = ck_alloc(MAX_ALLOC);
+
+  }
+
+  #endif
+
+  if (get_afl_env("AFL_ABUNDANT_CUT_OFF") && !afl->coverage_estimation) {
+
+    FATAL("AFL_ABUNDANT_CUT_OFF needs AFL_CODE_COVERAGE set!");
+
+  }
 
   if (afl->afl_env.afl_autoresume) {