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-rw-r--r--src/afl-fuzz-one.c1230
1 files changed, 792 insertions, 438 deletions
diff --git a/src/afl-fuzz-one.c b/src/afl-fuzz-one.c
index c6e9a295..74bb8cbc 100644
--- a/src/afl-fuzz-one.c
+++ b/src/afl-fuzz-one.c
@@ -5,11 +5,11 @@
    Originally written by Michal Zalewski
 
    Now maintained by Marc Heuse <mh@mh-sec.de>,
-                        Heiko Eißfeldt <heiko.eissfeldt@hexco.de> and
+                        Heiko Eissfeldt <heiko.eissfeldt@hexco.de> and
                         Andrea Fioraldi <andreafioraldi@gmail.com>
 
    Copyright 2016, 2017 Google Inc. All rights reserved.
-   Copyright 2019-2023 AFLplusplus Project. All rights reserved.
+   Copyright 2019-2024 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.
@@ -27,6 +27,7 @@
 #include <string.h>
 #include <limits.h>
 #include "cmplog.h"
+#include "afl-mutations.h"
 
 /* MOpt */
 
@@ -70,50 +71,6 @@ static int select_algorithm(afl_state_t *afl, u32 max_algorithm) {
 
 }
 
-/* Helper to choose random block len for block operations in fuzz_one().
-   Doesn't return zero, provided that max_len is > 0. */
-
-static inline u32 choose_block_len(afl_state_t *afl, u32 limit) {
-
-  u32 min_value, max_value;
-  u32 rlim = MIN(afl->queue_cycle, (u32)3);
-
-  if (unlikely(!afl->run_over10m)) { rlim = 1; }
-
-  switch (rand_below(afl, rlim)) {
-
-    case 0:
-      min_value = 1;
-      max_value = HAVOC_BLK_SMALL;
-      break;
-
-    case 1:
-      min_value = HAVOC_BLK_SMALL;
-      max_value = HAVOC_BLK_MEDIUM;
-      break;
-
-    default:
-
-      if (likely(rand_below(afl, 10))) {
-
-        min_value = HAVOC_BLK_MEDIUM;
-        max_value = HAVOC_BLK_LARGE;
-
-      } else {
-
-        min_value = HAVOC_BLK_LARGE;
-        max_value = HAVOC_BLK_XL;
-
-      }
-
-  }
-
-  if (min_value >= limit) { min_value = 1; }
-
-  return min_value + rand_below(afl, MIN(max_value, limit) - min_value + 1);
-
-}
-
 /* Helper function to see if a particular change (xor_val = old ^ new) could
    be a product of deterministic bit flips with the lengths and stepovers
    attempted by afl-fuzz. This is used to avoid dupes in some of the
@@ -372,9 +329,9 @@ u8 fuzz_one_original(afl_state_t *afl) {
   u32 len, temp_len;
   u32 j;
   u32 i;
-  u8 *in_buf, *out_buf, *orig_in, *ex_tmp, *eff_map = 0;
+  u8 *in_buf, *out_buf, *orig_in, *ex_tmp;
   u64 havoc_queued = 0, orig_hit_cnt, new_hit_cnt = 0, prev_cksum, _prev_cksum;
-  u32 splice_cycle = 0, perf_score = 100, orig_perf, eff_cnt = 1;
+  u32 splice_cycle = 0, perf_score = 100, orig_perf;
 
   u8 ret_val = 1, doing_det = 0;
 
@@ -442,18 +399,24 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
 #endif                                                     /* ^IGNORE_FINDS */
 
-  if (unlikely(afl->not_on_tty)) {
+  if (likely(afl->not_on_tty)) {
+
+    u8 time_tmp[64];
 
+    u_simplestring_time_diff(time_tmp, afl->prev_run_time + get_cur_time(),
+                             afl->start_time);
     ACTF(
-        "Fuzzing test case #%u (%u total, %llu crashes saved, "
+        "Fuzzing test case #%u (%u total, %llu crashes saved, state: %s, "
+        "mode=%s, "
         "perf_score=%0.0f, weight=%0.0f, favorite=%u, was_fuzzed=%u, "
-        "exec_us=%llu, hits=%u, map=%u, ascii=%u)...",
+        "exec_us=%llu, hits=%u, map=%u, ascii=%u, run_time=%s)...",
         afl->current_entry, afl->queued_items, afl->saved_crashes,
+        get_fuzzing_state(afl), afl->fuzz_mode ? "exploit" : "explore",
         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,
-        afl->queue_cur->bitmap_size, afl->queue_cur->is_ascii);
+        afl->queue_cur->bitmap_size, afl->queue_cur->is_ascii, time_tmp);
     fflush(stdout);
 
   }
@@ -582,12 +545,37 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
   }
 
+  u64 before_det_time = get_cur_time();
+#ifdef INTROSPECTION
+
+  u64 before_havoc_time;
+  u32 before_det_findings = afl->queued_items,
+      before_det_edges = count_non_255_bytes(afl, afl->virgin_bits),
+      before_havoc_findings, before_havoc_edges;
+  u8 is_logged = 0;
+
+#endif
+  if (!afl->skip_deterministic) {
+
+    if (!skip_deterministic_stage(afl, in_buf, out_buf, len, before_det_time)) {
+
+      goto abandon_entry;
+
+    }
+
+  }
+
+  u8 *skip_eff_map = afl->queue_cur->skipdet_e->skip_eff_map;
+
   /* Skip right away if -d is given, if it has not been chosen sufficiently
      often to warrant the expensive deterministic stage (fuzz_level), or
      if it has gone through deterministic testing in earlier, resumed runs
      (passed_det). */
+  /* if skipdet decide to skip the seed or no interesting bytes found,
+     we skip the whole deterministic stage as well */
 
   if (likely(afl->skip_deterministic) || likely(afl->queue_cur->passed_det) ||
+      likely(!afl->queue_cur->skipdet_e->quick_eff_bytes) ||
       likely(perf_score <
              (afl->queue_cur->depth * 30 <= afl->havoc_max_mult * 100
                   ? afl->queue_cur->depth * 30
@@ -614,13 +602,13 @@ u8 fuzz_one_original(afl_state_t *afl) {
    * SIMPLE BITFLIP (+dictionary construction) *
    *********************************************/
 
-#define FLIP_BIT(_ar, _b)                   \
-  do {                                      \
-                                            \
-    u8 *_arf = (u8 *)(_ar);                 \
-    u32 _bf = (_b);                         \
-    _arf[(_bf) >> 3] ^= (128 >> ((_bf)&7)); \
-                                            \
+#define FLIP_BIT(_ar, _b)                     \
+  do {                                        \
+                                              \
+    u8 *_arf = (u8 *)(_ar);                   \
+    u32 _bf = (_b);                           \
+    _arf[(_bf) >> 3] ^= (128 >> ((_bf) & 7)); \
+                                              \
   } while (0)
 
   /* Single walking bit. */
@@ -646,6 +634,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     afl->stage_cur_byte = afl->stage_cur >> 3;
 
+    if (!skip_eff_map[afl->stage_cur_byte]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     FLIP_BIT(out_buf, afl->stage_cur);
 
 #ifdef INTROSPECTION
@@ -762,6 +754,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     afl->stage_cur_byte = afl->stage_cur >> 3;
 
+    if (!skip_eff_map[afl->stage_cur_byte]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     FLIP_BIT(out_buf, afl->stage_cur);
     FLIP_BIT(out_buf, afl->stage_cur + 1);
 
@@ -797,6 +793,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     afl->stage_cur_byte = afl->stage_cur >> 3;
 
+    if (!skip_eff_map[afl->stage_cur_byte]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     FLIP_BIT(out_buf, afl->stage_cur);
     FLIP_BIT(out_buf, afl->stage_cur + 1);
     FLIP_BIT(out_buf, afl->stage_cur + 2);
@@ -824,34 +824,6 @@ u8 fuzz_one_original(afl_state_t *afl) {
   afl->queue_cur->stats_mutated += afl->stage_max;
 #endif
 
-  /* Effector map setup. These macros calculate:
-
-     EFF_APOS      - position of a particular file offset in the map.
-     EFF_ALEN      - length of a map with a particular number of bytes.
-     EFF_SPAN_ALEN - map span for a sequence of bytes.
-
-   */
-
-#define EFF_APOS(_p) ((_p) >> EFF_MAP_SCALE2)
-#define EFF_REM(_x) ((_x) & ((1 << EFF_MAP_SCALE2) - 1))
-#define EFF_ALEN(_l) (EFF_APOS(_l) + !!EFF_REM(_l))
-#define EFF_SPAN_ALEN(_p, _l) (EFF_APOS((_p) + (_l)-1) - EFF_APOS(_p) + 1)
-
-  /* Initialize effector map for the next step (see comments below). Always
-     flag first and last byte as doing something. */
-
-  eff_map = afl_realloc(AFL_BUF_PARAM(eff), EFF_ALEN(len));
-  if (unlikely(!eff_map)) { PFATAL("alloc"); }
-  memset(eff_map, 0, EFF_ALEN(len));
-  eff_map[0] = 1;
-
-  if (EFF_APOS(len - 1) != 0) {
-
-    eff_map[EFF_APOS(len - 1)] = 1;
-    ++eff_cnt;
-
-  }
-
   /* Walking byte. */
 
   afl->stage_name = "bitflip 8/8";
@@ -865,6 +837,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     afl->stage_cur_byte = afl->stage_cur;
 
+    if (!skip_eff_map[afl->stage_cur_byte]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     out_buf[afl->stage_cur] ^= 0xFF;
 
 #ifdef INTROSPECTION
@@ -874,59 +850,19 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     if (common_fuzz_stuff(afl, out_buf, len)) { goto abandon_entry; }
 
-    /* We also use this stage to pull off a simple trick: we identify
-       bytes that seem to have no effect on the current execution path
-       even when fully flipped - and we skip them during more expensive
-       deterministic stages, such as arithmetics or known ints. */
-
-    if (!eff_map[EFF_APOS(afl->stage_cur)]) {
-
-      u64 cksum;
-
-      /* If in non-instrumented mode or if the file is very short, just flag
-         everything without wasting time on checksums. */
-
-      if (!afl->non_instrumented_mode && len >= EFF_MIN_LEN) {
-
-        cksum = hash64(afl->fsrv.trace_bits, afl->fsrv.map_size, HASH_CONST);
-
-      } else {
-
-        cksum = ~prev_cksum;
-
-      }
-
-      if (cksum != prev_cksum) {
-
-        eff_map[EFF_APOS(afl->stage_cur)] = 1;
-        ++eff_cnt;
-
-      }
-
-    }
-
     out_buf[afl->stage_cur] ^= 0xFF;
 
   }
 
-  /* If the effector map is more than EFF_MAX_PERC dense, just flag the
-     whole thing as worth fuzzing, since we wouldn't be saving much time
-     anyway. */
+  /* New effective bytes calculation. */
 
-  if (eff_cnt != (u32)EFF_ALEN(len) &&
-      eff_cnt * 100 / EFF_ALEN(len) > EFF_MAX_PERC) {
+  for (i = 0; i < len; i++) {
 
-    memset(eff_map, 1, EFF_ALEN(len));
-
-    afl->blocks_eff_select += EFF_ALEN(len);
-
-  } else {
-
-    afl->blocks_eff_select += eff_cnt;
+    if (skip_eff_map[i]) afl->blocks_eff_select += 1;
 
   }
 
-  afl->blocks_eff_total += EFF_ALEN(len);
+  afl->blocks_eff_total += len;
 
   new_hit_cnt = afl->queued_items + afl->saved_crashes;
 
@@ -951,12 +887,9 @@ u8 fuzz_one_original(afl_state_t *afl) {
 
     /* Let's consult the effector map... */
 
-    if (!eff_map[EFF_APOS(i)] && !eff_map[EFF_APOS(i + 1)]) {
+    if (!skip_eff_map[i]) continue;
 
-      --afl->stage_max;
-      continue;
-
-    }
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
 
     afl->stage_cur_byte = i;
 
@@ -996,13 +929,10 @@ u8 fuzz_one_original(afl_state_t *afl) {
   for (i = 0; i < len - 3; ++i) {
 
     /* Let's consult the effector map... */
-    if (!eff_map[EFF_APOS(i)] && !eff_map[EFF_APOS(i + 1)] &&
-        !eff_map[EFF_APOS(i + 2)] && !eff_map[EFF_APOS(i + 3)]) {
 
-      --afl->stage_max;
-      continue;
+    if (!skip_eff_map[i]) continue;
 
-    }
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
 
     afl->stage_cur_byte = i;
 
@@ -1053,12 +983,9 @@ skip_bitflip:
 
     /* Let's consult the effector map... */
 
-    if (!eff_map[EFF_APOS(i)]) {
-
-      afl->stage_max -= 2 * ARITH_MAX;
-      continue;
+    if (!skip_eff_map[i]) continue;
 
-    }
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
 
     afl->stage_cur_byte = i;
 
@@ -1140,12 +1067,9 @@ skip_bitflip:
 
     /* Let's consult the effector map... */
 
-    if (!eff_map[EFF_APOS(i)] && !eff_map[EFF_APOS(i + 1)]) {
-
-      afl->stage_max -= 4 * ARITH_MAX;
-      continue;
+    if (!skip_eff_map[i]) continue;
 
-    }
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
 
     afl->stage_cur_byte = i;
 
@@ -1273,13 +1197,9 @@ skip_bitflip:
 
     /* Let's consult the effector map... */
 
-    if (!eff_map[EFF_APOS(i)] && !eff_map[EFF_APOS(i + 1)] &&
-        !eff_map[EFF_APOS(i + 2)] && !eff_map[EFF_APOS(i + 3)]) {
+    if (!skip_eff_map[i]) continue;
 
-      afl->stage_max -= 4 * ARITH_MAX;
-      continue;
-
-    }
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
 
     afl->stage_cur_byte = i;
 
@@ -1411,12 +1331,9 @@ skip_arith:
 
     /* Let's consult the effector map... */
 
-    if (!eff_map[EFF_APOS(i)]) {
-
-      afl->stage_max -= sizeof(interesting_8);
-      continue;
+    if (!skip_eff_map[i]) continue;
 
-    }
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
 
     afl->stage_cur_byte = i;
 
@@ -1474,12 +1391,9 @@ skip_arith:
 
     /* Let's consult the effector map... */
 
-    if (!eff_map[EFF_APOS(i)] && !eff_map[EFF_APOS(i + 1)]) {
+    if (!skip_eff_map[i]) continue;
 
-      afl->stage_max -= sizeof(interesting_16);
-      continue;
-
-    }
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
 
     afl->stage_cur_byte = i;
 
@@ -1565,13 +1479,9 @@ skip_arith:
 
     /* Let's consult the effector map... */
 
-    if (!eff_map[EFF_APOS(i)] && !eff_map[EFF_APOS(i + 1)] &&
-        !eff_map[EFF_APOS(i + 2)] && !eff_map[EFF_APOS(i + 3)]) {
-
-      afl->stage_max -= sizeof(interesting_32) >> 1;
-      continue;
+    if (!skip_eff_map[i]) continue;
 
-    }
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
 
     afl->stage_cur_byte = i;
 
@@ -1663,6 +1573,10 @@ skip_interest:
 
     u32 last_len = 0;
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     /* Extras are sorted by size, from smallest to largest. This means
@@ -1680,9 +1594,7 @@ skip_interest:
       if ((afl->extras_cnt > afl->max_det_extras &&
            rand_below(afl, afl->extras_cnt) >= afl->max_det_extras) ||
           afl->extras[j].len > len - i ||
-          !memcmp(afl->extras[j].data, out_buf + i, afl->extras[j].len) ||
-          !memchr(eff_map + EFF_APOS(i), 1,
-                  EFF_SPAN_ALEN(i, afl->extras[j].len))) {
+          !memcmp(afl->extras[j].data, out_buf + i, afl->extras[j].len)) {
 
         --afl->stage_max;
         continue;
@@ -1730,6 +1642,10 @@ skip_interest:
 
   for (i = 0; i <= (u32)len; ++i) {
 
+    if (!skip_eff_map[i % len]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 0; j < afl->extras_cnt; ++j) {
@@ -1792,6 +1708,10 @@ skip_user_extras:
 
     u32 last_len = 0;
 
+    if (!skip_eff_map[i]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     u32 min_extra_len = MIN(afl->a_extras_cnt, (u32)USE_AUTO_EXTRAS);
@@ -1800,9 +1720,7 @@ skip_user_extras:
       /* See the comment in the earlier code; extras are sorted by size. */
 
       if (afl->a_extras[j].len > len - i ||
-          !memcmp(afl->a_extras[j].data, out_buf + i, afl->a_extras[j].len) ||
-          !memchr(eff_map + EFF_APOS(i), 1,
-                  EFF_SPAN_ALEN(i, afl->a_extras[j].len))) {
+          !memcmp(afl->a_extras[j].data, out_buf + i, afl->a_extras[j].len)) {
 
         --afl->stage_max;
         continue;
@@ -1850,6 +1768,10 @@ skip_user_extras:
 
   for (i = 0; i <= (u32)len; ++i) {
 
+    if (!skip_eff_map[i % len]) continue;
+
+    if (is_det_timeout(before_det_time, 0)) { goto custom_mutator_stage; }
+
     afl->stage_cur_byte = i;
 
     for (j = 0; j < afl->a_extras_cnt; ++j) {
@@ -1912,6 +1834,7 @@ custom_mutator_stage:
 
   afl->stage_name = "custom mutator";
   afl->stage_short = "custom";
+  afl->stage_cur = 0;
   afl->stage_val_type = STAGE_VAL_NONE;
   bool has_custom_fuzz = false;
   u32  shift = unlikely(afl->custom_only) ? 7 : 8;
@@ -1931,6 +1854,8 @@ custom_mutator_stage:
 
     if (el->afl_custom_fuzz) {
 
+      havoc_queued = afl->queued_items;
+
       afl->current_custom_fuzz = el;
       afl->stage_name = el->name_short;
 
@@ -2054,6 +1979,19 @@ custom_mutator_stage:
 
 havoc_stage:
 
+#ifdef INTROSPECTION
+
+  if (!is_logged) {
+
+    is_logged = 1;
+    before_havoc_findings = afl->queued_items;
+    before_havoc_edges = count_non_255_bytes(afl, afl->virgin_bits);
+    before_havoc_time = get_cur_time();
+
+  }
+
+#endif
+
   if (unlikely(afl->custom_only)) {
 
     /* Force UI update */
@@ -2122,45 +2060,97 @@ havoc_stage:
   /* We essentially just do several thousand runs (depending on perf_score)
      where we take the input file and make random stacked tweaks. */
 
-#define MAX_HAVOC_ENTRY 64
-#define MUTATE_ASCII_DICT 64
+  u32 *mutation_array;
+  u32  stack_max, rand_max;  // stack_max_pow = afl->havoc_stack_pow2;
+
+  switch (afl->input_mode) {
+
+    case 1: {  // TEXT
 
-  u32 r_max, r;
+      if (likely(afl->fuzz_mode == 0)) {  // is exploration?
+        mutation_array = (unsigned int *)&binary_array;
+        rand_max = MUT_BIN_ARRAY_SIZE;
 
-  r_max = (MAX_HAVOC_ENTRY + 1) + (afl->extras_cnt ? 4 : 0) +
-          (afl->a_extras_cnt
-               ? (unlikely(afl->cmplog_binary && afl->queue_cur->is_ascii)
-                      ? MUTATE_ASCII_DICT
-                      : 4)
-               : 0);
+      } else {  // exploitation mode
 
-  if (unlikely(afl->expand_havoc && afl->ready_for_splicing_count > 1)) {
+        mutation_array = (unsigned int *)&text_array;
+        rand_max = MUT_TXT_ARRAY_SIZE;
 
-    /* add expensive havoc cases here, they are activated after a full
-       cycle without finds happened */
+      }
+
+      break;
+
+    }
+
+    case 2: {  // BINARY
+
+      if (likely(afl->fuzz_mode == 0)) {  // is exploration?
+        mutation_array = (unsigned int *)&mutation_strategy_exploration_binary;
+        rand_max = MUT_STRATEGY_ARRAY_SIZE;
+
+      } else {  // exploitation mode
+
+        mutation_array = (unsigned int *)&mutation_strategy_exploitation_binary;
+        rand_max = MUT_STRATEGY_ARRAY_SIZE;
+        // or this one? we do not have enough binary bug benchmarks :-(
+        // mutation_array = (unsigned int *)&binary_array;
+        // rand_max = MUT_BIN_ARRAY_SIZE;
+
+      }
+
+      break;
+
+    }
+
+    default: {  // DEFAULT/GENERIC
 
-    r_max += 4;
+      if (likely(afl->fuzz_mode == 0)) {  // is exploration?
+        mutation_array = (unsigned int *)&binary_array;
+        rand_max = MUT_BIN_ARRAY_SIZE;
+
+      } else {  // exploitation mode
+
+        mutation_array = (unsigned int *)&text_array;
+        rand_max = MUT_TXT_ARRAY_SIZE;
+
+      }
+
+      break;
+
+    }
 
   }
 
-  if (unlikely(get_cur_time() - afl->last_find_time > 5000 /* 5 seconds */ &&
-               afl->ready_for_splicing_count > 1)) {
+  /*
+  if (temp_len < 64) {
+
+    --stack_max_pow;
 
-    /* add expensive havoc cases here if there is no findings in the last 5s */
+  } else if (temp_len <= 8096) {
 
-    r_max += 4;
+    ++stack_max_pow;
+
+  } else {
+
+    ++stack_max_pow;
 
   }
 
+  */
+
+  stack_max = 1 << (1 + rand_below(afl, afl->havoc_stack_pow2));
+
+  // + (afl->extras_cnt ? 2 : 0) + (afl->a_extras_cnt ? 2 : 0);
+
   for (afl->stage_cur = 0; afl->stage_cur < afl->stage_max; ++afl->stage_cur) {
 
-    u32 use_stacking = 1 << (1 + rand_below(afl, afl->havoc_stack_pow2));
+    u32 use_stacking = 1 + rand_below(afl, stack_max);
 
     afl->stage_cur_val = use_stacking;
 
 #ifdef INTROSPECTION
-    snprintf(afl->mutation, sizeof(afl->mutation), "%s HAVOC-%u",
-             afl->queue_cur->fname, use_stacking);
+    snprintf(afl->mutation, sizeof(afl->mutation), "%s HAVOC-%u-%u",
+             afl->queue_cur->fname, afl->queue_cur->is_ascii, use_stacking);
 #endif
 
     for (i = 0; i < use_stacking; ++i) {
@@ -2169,8 +2159,8 @@ havoc_stage:
 
         LIST_FOREACH(&afl->custom_mutator_list, struct custom_mutator, {
 
-          if (el->stacked_custom &&
-              rand_below(afl, 100) < el->stacked_custom_prob) {
+          if (unlikely(el->stacked_custom &&
+                       rand_below(afl, 100) < el->stacked_custom_prob)) {
 
             u8    *custom_havoc_buf = NULL;
             size_t new_len = el->afl_custom_havoc_mutation(
@@ -2200,159 +2190,173 @@ havoc_stage:
 
       }
 
-      switch ((r = rand_below(afl, r_max))) {
+    retry_havoc_step: {
+
+      u32 r = rand_below(afl, rand_max), item;
+
+      switch (mutation_array[r]) {
 
-        case 0 ... 3: {
+        case MUT_FLIPBIT: {
 
           /* Flip a single bit somewhere. Spooky! */
+          u8  bit = rand_below(afl, 8);
+          u32 off = rand_below(afl, temp_len);
+          out_buf[off] ^= 1 << bit;
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " FLIP_BIT1");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " FLIP-BIT_%u", bit);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          FLIP_BIT(out_buf, rand_below(afl, temp_len << 3));
           break;
 
         }
 
-        case 4 ... 7: {
+        case MUT_INTERESTING8: {
 
           /* Set byte to interesting value. */
 
+          item = rand_below(afl, sizeof(interesting_8));
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING8");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING8_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          out_buf[rand_below(afl, temp_len)] =
-              interesting_8[rand_below(afl, sizeof(interesting_8))];
+          out_buf[rand_below(afl, temp_len)] = interesting_8[item];
           break;
 
         }
 
-        case 8 ... 9: {
+        case MUT_INTERESTING16: {
 
           /* Set word to interesting value, little endian. */
 
-          if (temp_len < 2) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
 
+          item = rand_below(afl, sizeof(interesting_16) >> 1);
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING16");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING16_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
+
           *(u16 *)(out_buf + rand_below(afl, temp_len - 1)) =
-              interesting_16[rand_below(afl, sizeof(interesting_16) >> 1)];
+              interesting_16[item];
 
           break;
 
         }
 
-        case 10 ... 11: {
+        case MUT_INTERESTING16BE: {
 
           /* Set word to interesting value, big endian. */
 
-          if (temp_len < 2) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
 
+          item = rand_below(afl, sizeof(interesting_16) >> 1);
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING16BE");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING16BE_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          *(u16 *)(out_buf + rand_below(afl, temp_len - 1)) = SWAP16(
-              interesting_16[rand_below(afl, sizeof(interesting_16) >> 1)]);
+          *(u16 *)(out_buf + rand_below(afl, temp_len - 1)) =
+              SWAP16(interesting_16[item]);
 
           break;
 
         }
 
-        case 12 ... 13: {
+        case MUT_INTERESTING32: {
 
           /* Set dword to interesting value, little endian. */
 
-          if (temp_len < 4) { break; }
+          if (unlikely(temp_len < 4)) { break; }  // no retry
 
+          item = rand_below(afl, sizeof(interesting_32) >> 2);
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING32");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING32_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
+
           *(u32 *)(out_buf + rand_below(afl, temp_len - 3)) =
-              interesting_32[rand_below(afl, sizeof(interesting_32) >> 2)];
+              interesting_32[item];
 
           break;
 
         }
 
-        case 14 ... 15: {
+        case MUT_INTERESTING32BE: {
 
           /* Set dword to interesting value, big endian. */
 
-          if (temp_len < 4) { break; }
+          if (unlikely(temp_len < 4)) { break; }  // no retry
 
+          item = rand_below(afl, sizeof(interesting_32) >> 2);
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING32BE");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INTERESTING32BE_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          *(u32 *)(out_buf + rand_below(afl, temp_len - 3)) = SWAP32(
-              interesting_32[rand_below(afl, sizeof(interesting_32) >> 2)]);
+          *(u32 *)(out_buf + rand_below(afl, temp_len - 3)) =
+              SWAP32(interesting_32[item]);
 
           break;
 
         }
 
-        case 16 ... 19: {
+        case MUT_ARITH8_: {
 
           /* Randomly subtract from byte. */
 
+          item = 1 + rand_below(afl, ARITH_MAX);
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH8_");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH8-_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          out_buf[rand_below(afl, temp_len)] -= 1 + rand_below(afl, ARITH_MAX);
+          out_buf[rand_below(afl, temp_len)] -= item;
           break;
 
         }
 
-        case 20 ... 23: {
+        case MUT_ARITH8: {
 
           /* Randomly add to byte. */
 
+          item = 1 + rand_below(afl, ARITH_MAX);
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH8+");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH8+_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          out_buf[rand_below(afl, temp_len)] += 1 + rand_below(afl, ARITH_MAX);
+          out_buf[rand_below(afl, temp_len)] += item;
           break;
 
         }
 
-        case 24 ... 25: {
+        case MUT_ARITH16_: {
 
           /* Randomly subtract from word, little endian. */
 
-          if (temp_len < 2) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
 
           u32 pos = rand_below(afl, temp_len - 1);
+          item = 1 + rand_below(afl, ARITH_MAX);
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH16_-%u", pos);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH16-_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          *(u16 *)(out_buf + pos) -= 1 + rand_below(afl, ARITH_MAX);
+          *(u16 *)(out_buf + pos) -= item;
 
           break;
 
         }
 
-        case 26 ... 27: {
+        case MUT_ARITH16BE_: {
 
           /* Randomly subtract from word, big endian. */
 
-          if (temp_len < 2) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
 
           u32 pos = rand_below(afl, temp_len - 1);
           u16 num = 1 + rand_below(afl, ARITH_MAX);
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH16_BE-%u_%u", pos,
-                   num);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH16BE-_%u", num);
           strcat(afl->mutation, afl->m_tmp);
 #endif
           *(u16 *)(out_buf + pos) =
@@ -2362,36 +2366,36 @@ havoc_stage:
 
         }
 
-        case 28 ... 29: {
+        case MUT_ARITH16: {
 
           /* Randomly add to word, little endian. */
 
-          if (temp_len < 2) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
 
           u32 pos = rand_below(afl, temp_len - 1);
+          item = 1 + rand_below(afl, ARITH_MAX);
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH16+-%u", pos);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH16+_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          *(u16 *)(out_buf + pos) += 1 + rand_below(afl, ARITH_MAX);
+          *(u16 *)(out_buf + pos) += item;
 
           break;
 
         }
 
-        case 30 ... 31: {
+        case MUT_ARITH16BE: {
 
           /* Randomly add to word, big endian. */
 
-          if (temp_len < 2) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
 
           u32 pos = rand_below(afl, temp_len - 1);
           u16 num = 1 + rand_below(afl, ARITH_MAX);
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH16+BE-%u_%u", pos,
-                   num);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH16BE+__%u", num);
           strcat(afl->mutation, afl->m_tmp);
 #endif
           *(u16 *)(out_buf + pos) =
@@ -2401,36 +2405,36 @@ havoc_stage:
 
         }
 
-        case 32 ... 33: {
+        case MUT_ARITH32_: {
 
           /* Randomly subtract from dword, little endian. */
 
-          if (temp_len < 4) { break; }
+          if (unlikely(temp_len < 4)) { break; }  // no retry
 
           u32 pos = rand_below(afl, temp_len - 3);
+          item = 1 + rand_below(afl, ARITH_MAX);
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH32_-%u", pos);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH32-_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          *(u32 *)(out_buf + pos) -= 1 + rand_below(afl, ARITH_MAX);
+          *(u32 *)(out_buf + pos) -= item;
 
           break;
 
         }
 
-        case 34 ... 35: {
+        case MUT_ARITH32BE_: {
 
           /* Randomly subtract from dword, big endian. */
 
-          if (temp_len < 4) { break; }
+          if (unlikely(temp_len < 4)) { break; }  // no retry
 
           u32 pos = rand_below(afl, temp_len - 3);
           u32 num = 1 + rand_below(afl, ARITH_MAX);
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH32_BE-%u-%u", pos,
-                   num);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH32BE-_%u", num);
           strcat(afl->mutation, afl->m_tmp);
 #endif
           *(u32 *)(out_buf + pos) =
@@ -2440,36 +2444,36 @@ havoc_stage:
 
         }
 
-        case 36 ... 37: {
+        case MUT_ARITH32: {
 
           /* Randomly add to dword, little endian. */
 
-          if (temp_len < 4) { break; }
+          if (unlikely(temp_len < 4)) { break; }  // no retry
 
           u32 pos = rand_below(afl, temp_len - 3);
+          item = 1 + rand_below(afl, ARITH_MAX);
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH32+-%u", pos);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH32+_%u", item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          *(u32 *)(out_buf + pos) += 1 + rand_below(afl, ARITH_MAX);
+          *(u32 *)(out_buf + pos) += item;
 
           break;
 
         }
 
-        case 38 ... 39: {
+        case MUT_ARITH32BE: {
 
           /* Randomly add to dword, big endian. */
 
-          if (temp_len < 4) { break; }
+          if (unlikely(temp_len < 4)) { break; }  // no retry
 
           u32 pos = rand_below(afl, temp_len - 3);
           u32 num = 1 + rand_below(afl, ARITH_MAX);
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH32+BE-%u-%u", pos,
-                   num);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ARITH32BE+_%u", num);
           strcat(afl->mutation, afl->m_tmp);
 #endif
           *(u32 *)(out_buf + pos) =
@@ -2479,24 +2483,27 @@ havoc_stage:
 
         }
 
-        case 40 ... 43: {
+        case MUT_RAND8: {
 
           /* Just set a random byte to a random value. Because,
              why not. We use XOR with 1-255 to eliminate the
              possibility of a no-op. */
 
+          u32 pos = rand_below(afl, temp_len);
+          item = 1 + rand_below(afl, 255);
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " RAND8");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " RAND8_%u",
+                   out_buf[pos] ^ item);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          out_buf[rand_below(afl, temp_len)] ^= 1 + rand_below(afl, 255);
+          out_buf[pos] ^= item;
           break;
 
         }
 
-        case 44 ... 46: {
+        case MUT_CLONE_COPY: {
 
-          if (temp_len + HAVOC_BLK_XL < MAX_FILE) {
+          if (likely(temp_len + HAVOC_BLK_XL < MAX_FILE)) {
 
             /* Clone bytes. */
 
@@ -2505,8 +2512,8 @@ havoc_stage:
             u32 clone_to = rand_below(afl, temp_len);
 
 #ifdef INTROSPECTION
-            snprintf(afl->m_tmp, sizeof(afl->m_tmp), " CLONE-%s-%u-%u-%u",
-                     "clone", clone_from, clone_to, clone_len);
+            snprintf(afl->m_tmp, sizeof(afl->m_tmp), " CLONE-%s_%u_%u_%u",
+                     "COPY", clone_from, clone_to, clone_len);
             strcat(afl->mutation, afl->m_tmp);
 #endif
             u8 *new_buf =
@@ -2529,24 +2536,35 @@ havoc_stage:
             afl_swap_bufs(AFL_BUF_PARAM(out), AFL_BUF_PARAM(out_scratch));
             temp_len += clone_len;
 
+          } else if (unlikely(temp_len < 8)) {
+
+            break;
+
+          } else {
+
+            goto retry_havoc_step;
+
           }
 
           break;
 
         }
 
-        case 47: {
+        case MUT_CLONE_FIXED: {
 
-          if (temp_len + HAVOC_BLK_XL < MAX_FILE) {
+          if (likely(temp_len + HAVOC_BLK_XL < MAX_FILE)) {
 
             /* Insert a block of constant bytes (25%). */
 
             u32 clone_len = choose_block_len(afl, HAVOC_BLK_XL);
             u32 clone_to = rand_below(afl, temp_len);
+            u32 strat = rand_below(afl, 2);
+            u32 clone_from = clone_to ? clone_to - 1 : 0;
+            item = strat ? rand_below(afl, 256) : out_buf[clone_from];
 
 #ifdef INTROSPECTION
-            snprintf(afl->m_tmp, sizeof(afl->m_tmp), " CLONE-%s-%u-%u",
-                     "insert", clone_to, clone_len);
+            snprintf(afl->m_tmp, sizeof(afl->m_tmp), " CLONE-%s_%u_%u_%u",
+                     "FIXED", strat, clone_to, clone_len);
             strcat(afl->mutation, afl->m_tmp);
 #endif
             u8 *new_buf =
@@ -2559,10 +2577,7 @@ havoc_stage:
 
             /* Inserted part */
 
-            memset(new_buf + clone_to,
-                   rand_below(afl, 2) ? rand_below(afl, 256)
-                                      : out_buf[rand_below(afl, temp_len)],
-                   clone_len);
+            memset(new_buf + clone_to, item, clone_len);
 
             /* Tail */
             memcpy(new_buf + clone_to + clone_len, out_buf + clone_to,
@@ -2572,66 +2587,77 @@ havoc_stage:
             afl_swap_bufs(AFL_BUF_PARAM(out), AFL_BUF_PARAM(out_scratch));
             temp_len += clone_len;
 
+          } else if (unlikely(temp_len < 8)) {
+
+            break;
+
+          } else {
+
+            goto retry_havoc_step;
+
           }
 
           break;
 
         }
 
-        case 48 ... 50: {
+        case MUT_OVERWRITE_COPY: {
 
           /* Overwrite bytes with a randomly selected chunk bytes. */
 
-          if (temp_len < 2) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
 
-          u32 copy_len = choose_block_len(afl, temp_len - 1);
-          u32 copy_from = rand_below(afl, temp_len - copy_len + 1);
-          u32 copy_to = rand_below(afl, temp_len - copy_len + 1);
+          u32 copy_from, copy_to,
+              copy_len = choose_block_len(afl, temp_len - 1);
 
-          if (likely(copy_from != copy_to)) {
+          do {
+
+            copy_from = rand_below(afl, temp_len - copy_len + 1);
+            copy_to = rand_below(afl, temp_len - copy_len + 1);
+
+          } while (unlikely(copy_from == copy_to));
 
 #ifdef INTROSPECTION
-            snprintf(afl->m_tmp, sizeof(afl->m_tmp), " OVERWRITE_COPY-%u-%u-%u",
-                     copy_from, copy_to, copy_len);
-            strcat(afl->mutation, afl->m_tmp);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " OVERWRITE-COPY_%u_%u_%u",
+                   copy_from, copy_to, copy_len);
+          strcat(afl->mutation, afl->m_tmp);
 #endif
-            memmove(out_buf + copy_to, out_buf + copy_from, copy_len);
-
-          }
+          memmove(out_buf + copy_to, out_buf + copy_from, copy_len);
 
           break;
 
         }
 
-        case 51: {
+        case MUT_OVERWRITE_FIXED: {
 
           /* Overwrite bytes with fixed bytes. */
 
-          if (temp_len < 2) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
 
           u32 copy_len = choose_block_len(afl, temp_len - 1);
           u32 copy_to = rand_below(afl, temp_len - copy_len + 1);
+          u32 strat = rand_below(afl, 2);
+          u32 copy_from = copy_to ? copy_to - 1 : 0;
+          item = strat ? rand_below(afl, 256) : out_buf[copy_from];
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " OVERWRITE_FIXED-%u-%u",
-                   copy_to, copy_len);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp),
+                   " OVERWRITE-FIXED_%u_%u_%u-%u", strat, item, copy_to,
+                   copy_len);
           strcat(afl->mutation, afl->m_tmp);
 #endif
-          memset(out_buf + copy_to,
-                 rand_below(afl, 2) ? rand_below(afl, 256)
-                                    : out_buf[rand_below(afl, temp_len)],
-                 copy_len);
+          memset(out_buf + copy_to, item, copy_len);
 
           break;
 
         }
 
-        case 52: {
+        case MUT_BYTEADD: {
 
           /* Increase byte by 1. */
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ADDBYTE_");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " BYTEADD_");
           strcat(afl->mutation, afl->m_tmp);
 #endif
           out_buf[rand_below(afl, temp_len)]++;
@@ -2639,12 +2665,12 @@ havoc_stage:
 
         }
 
-        case 53: {
+        case MUT_BYTESUB: {
 
           /* Decrease byte by 1. */
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " SUBBYTE_");
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " BYTESUB_");
           strcat(afl->mutation, afl->m_tmp);
 #endif
           out_buf[rand_below(afl, temp_len)]--;
@@ -2652,9 +2678,9 @@ havoc_stage:
 
         }
 
-        case 54: {
+        case MUT_FLIP8: {
 
-          /* Flip byte. */
+          /* Flip byte with a XOR 0xff. This is the same as NEG. */
 
 #ifdef INTROSPECTION
           snprintf(afl->m_tmp, sizeof(afl->m_tmp), " FLIP8_");
@@ -2665,9 +2691,9 @@ havoc_stage:
 
         }
 
-        case 55 ... 56: {
+        case MUT_SWITCH: {
 
-          if (temp_len < 4) { break; }
+          if (unlikely(temp_len < 4)) { break; }  // no retry
 
           /* Switch bytes. */
 
@@ -2677,7 +2703,7 @@ havoc_stage:
 
             switch_to = rand_below(afl, temp_len);
 
-          } while (switch_from == switch_to);
+          } while (unlikely(switch_from == switch_to));
 
           if (switch_from < switch_to) {
 
@@ -2694,7 +2720,7 @@ havoc_stage:
           switch_len = choose_block_len(afl, MIN(switch_len, to_end));
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " SWITCH-%s-%u-%u-%u",
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " SWITCH-%s_%u_%u_%u",
                    "switch", switch_from, switch_to, switch_len);
           strcat(afl->mutation, afl->m_tmp);
 #endif
@@ -2717,12 +2743,11 @@ havoc_stage:
 
         }
 
-        // MAX_HAVOC_ENTRY = 64
-        case 57 ... MAX_HAVOC_ENTRY: {
+        case MUT_DEL: {
 
           /* Delete bytes. */
 
-          if (temp_len < 2) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
 
           /* Don't delete too much. */
 
@@ -2730,7 +2755,7 @@ havoc_stage:
           u32 del_from = rand_below(afl, temp_len - del_len + 1);
 
 #ifdef INTROSPECTION
-          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " DEL-%u-%u", del_from,
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " DEL_%u_%u", del_from,
                    del_len);
           strcat(afl->mutation, afl->m_tmp);
 #endif
@@ -2743,135 +2768,401 @@ havoc_stage:
 
         }
 
-        default:
+        case MUT_SHUFFLE: {
 
-          r -= (MAX_HAVOC_ENTRY + 1);
+          /* Shuffle bytes. */
 
-          if (afl->extras_cnt) {
+          if (unlikely(temp_len < 4)) { break; }  // no retry
 
-            if (r < 2) {
+          u32 len = choose_block_len(afl, temp_len - 1);
+          u32 off = rand_below(afl, temp_len - len + 1);
 
-              /* Use the dictionary. */
+#ifdef INTROSPECTION
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " SHUFFLE_%u", len);
+          strcat(afl->mutation, afl->m_tmp);
+#endif
+
+          for (u32 i = len - 1; i > 0; i--) {
+
+            u32 j;
+            do {
+
+              j = rand_below(afl, i + 1);
+
+            } while (unlikely(i == j));
 
-              u32 use_extra = rand_below(afl, afl->extras_cnt);
-              u32 extra_len = afl->extras[use_extra].len;
+            unsigned char temp = out_buf[off + i];
+            out_buf[off + i] = out_buf[off + j];
+            out_buf[off + j] = temp;
 
-              if (extra_len > temp_len) { break; }
+          }
+
+          break;
+
+        }
+
+        case MUT_DELONE: {
+
+          /* Delete bytes. */
+
+          if (unlikely(temp_len < 2)) { break; }  // no retry
+
+          /* Don't delete too much. */
+
+          u32 del_len = 1;
+          u32 del_from = rand_below(afl, temp_len - del_len + 1);
 
-              u32 insert_at = rand_below(afl, temp_len - extra_len + 1);
 #ifdef INTROSPECTION
-              snprintf(afl->m_tmp, sizeof(afl->m_tmp), " EXTRA_OVERWRITE-%u-%u",
-                       insert_at, extra_len);
-              strcat(afl->mutation, afl->m_tmp);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " DELONE_%u", del_from);
+          strcat(afl->mutation, afl->m_tmp);
 #endif
-              memcpy(out_buf + insert_at, afl->extras[use_extra].data,
-                     extra_len);
+          memmove(out_buf + del_from, out_buf + del_from + del_len,
+                  temp_len - del_from - del_len);
 
-              break;
+          temp_len -= del_len;
+
+          break;
+
+        }
 
-            } else if (r < 4) {
+        case MUT_INSERTONE: {
 
-              u32 use_extra = rand_below(afl, afl->extras_cnt);
-              u32 extra_len = afl->extras[use_extra].len;
-              if (temp_len + extra_len >= MAX_FILE) { break; }
+          if (unlikely(temp_len < 2)) { break; }  // no retry
+
+          u32 clone_len = 1;
+          u32 clone_to = rand_below(afl, temp_len);
+          u32 strat = rand_below(afl, 2);
+          u32 clone_from = clone_to ? clone_to - 1 : 0;
+          item = strat ? rand_below(afl, 256) : out_buf[clone_from];
 
-              u8 *ptr = afl->extras[use_extra].data;
-              u32 insert_at = rand_below(afl, temp_len + 1);
 #ifdef INTROSPECTION
-              snprintf(afl->m_tmp, sizeof(afl->m_tmp), " EXTRA_INSERT-%u-%u",
-                       insert_at, extra_len);
-              strcat(afl->mutation, afl->m_tmp);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INSERTONE_%u_%u", strat,
+                   clone_to);
+          strcat(afl->mutation, afl->m_tmp);
 #endif
+          u8 *new_buf =
+              afl_realloc(AFL_BUF_PARAM(out_scratch), temp_len + clone_len);
+          if (unlikely(!new_buf)) { PFATAL("alloc"); }
 
-              out_buf = afl_realloc(AFL_BUF_PARAM(out), temp_len + extra_len);
-              if (unlikely(!out_buf)) { PFATAL("alloc"); }
+          /* Head */
 
-              /* Tail */
-              memmove(out_buf + insert_at + extra_len, out_buf + insert_at,
-                      temp_len - insert_at);
+          memcpy(new_buf, out_buf, clone_to);
 
-              /* Inserted part */
-              memcpy(out_buf + insert_at, ptr, extra_len);
-              temp_len += extra_len;
+          /* Inserted part */
 
-              break;
+          memset(new_buf + clone_to, item, clone_len);
 
-            } else {
+          /* Tail */
+          memcpy(new_buf + clone_to + clone_len, out_buf + clone_to,
+                 temp_len - clone_to);
 
-              r -= 4;
+          out_buf = new_buf;
+          afl_swap_bufs(AFL_BUF_PARAM(out), AFL_BUF_PARAM(out_scratch));
+          temp_len += clone_len;
 
-            }
+          break;
+
+        }
+
+        case MUT_ASCIINUM: {
+
+          if (unlikely(temp_len < 4)) { break; }  // no retry
+
+          u32 off = rand_below(afl, temp_len), off2 = off, cnt = 0;
+
+          while (off2 + cnt < temp_len && !isdigit(out_buf[off2 + cnt])) {
+
+            ++cnt;
 
           }
 
-          if (afl->a_extras_cnt) {
+          // none found, wrap
+          if (off2 + cnt == temp_len) {
 
-            u32 r_cmp = 2;
+            off2 = 0;
+            cnt = 0;
 
-            if (unlikely(afl->cmplog_binary && afl->queue_cur->is_ascii)) {
+            while (cnt < off && !isdigit(out_buf[off2 + cnt])) {
 
-              r_cmp = MUTATE_ASCII_DICT >> 1;
+              ++cnt;
 
             }
 
-            if (r < r_cmp) {
+            if (cnt == off) {
 
-              /* Use the dictionary. */
+              if (temp_len < 8) {
 
-              u32 use_extra = rand_below(afl, afl->a_extras_cnt);
-              u32 extra_len = afl->a_extras[use_extra].len;
+                break;
 
-              if (extra_len > temp_len) { break; }
+              } else {
 
-              u32 insert_at = rand_below(afl, temp_len - extra_len + 1);
-#ifdef INTROSPECTION
-              snprintf(afl->m_tmp, sizeof(afl->m_tmp),
-                       " AUTO_EXTRA_OVERWRITE-%u-%u", insert_at, extra_len);
-              strcat(afl->mutation, afl->m_tmp);
-#endif
-              memcpy(out_buf + insert_at, afl->a_extras[use_extra].data,
-                     extra_len);
+                goto retry_havoc_step;
+
+              }
+
+            }
+
+          }
+
+          off = off2 + cnt;
+          off2 = off + 1;
+
+          while (off2 < temp_len && isdigit(out_buf[off2])) {
+
+            ++off2;
+
+          }
 
+          s64 val = out_buf[off] - '0';
+          for (u32 i = off + 1; i < off2; ++i) {
+
+            val = (val * 10) + out_buf[i] - '0';
+
+          }
+
+          if (off && out_buf[off - 1] == '-') { val = -val; }
+
+          u32 strat = rand_below(afl, 8);
+          switch (strat) {
+
+            case 0:
+              val++;
+              break;
+            case 1:
+              val--;
+              break;
+            case 2:
+              val *= 2;
+              break;
+            case 3:
+              val /= 2;
               break;
+            case 4:
+              if (likely(val && (u64)val < 0x19999999)) {
 
-            } else if (r < (r_cmp << 1)) {
+                val = (u64)rand_next(afl) % (u64)((u64)val * 10);
+
+              } else {
 
-              u32 use_extra = rand_below(afl, afl->a_extras_cnt);
-              u32 extra_len = afl->a_extras[use_extra].len;
-              if (temp_len + extra_len >= MAX_FILE) { break; }
+                val = rand_below(afl, 256);
+
+              }
+
+              break;
+            case 5:
+              val += rand_below(afl, 256);
+              break;
+            case 6:
+              val -= rand_below(afl, 256);
+              break;
+            case 7:
+              val = ~(val);
+              break;
+
+          }
 
-              u8 *ptr = afl->a_extras[use_extra].data;
-              u32 insert_at = rand_below(afl, temp_len + 1);
 #ifdef INTROSPECTION
-              snprintf(afl->m_tmp, sizeof(afl->m_tmp),
-                       " AUTO_EXTRA_INSERT-%u-%u", insert_at, extra_len);
-              strcat(afl->mutation, afl->m_tmp);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " ASCIINUM_%u_%u_%u",
+                   afl->queue_cur->is_ascii, strat, off);
+          strcat(afl->mutation, afl->m_tmp);
 #endif
+          // fprintf(stderr, "val: %u-%u = %ld\n", off, off2, val);
+
+          char buf[20];
+          snprintf(buf, sizeof(buf), "%" PRId64, val);
 
-              out_buf = afl_realloc(AFL_BUF_PARAM(out), temp_len + extra_len);
-              if (unlikely(!out_buf)) { PFATAL("alloc"); }
+          // fprintf(stderr, "BEFORE: %s\n", out_buf);
 
-              /* Tail */
-              memmove(out_buf + insert_at + extra_len, out_buf + insert_at,
-                      temp_len - insert_at);
+          u32 old_len = off2 - off;
+          u32 new_len = strlen(buf);
 
-              /* Inserted part */
-              memcpy(out_buf + insert_at, ptr, extra_len);
-              temp_len += extra_len;
+          if (old_len == new_len) {
+
+            memcpy(out_buf + off, buf, new_len);
+
+          } else {
+
+            u8 *new_buf = afl_realloc(AFL_BUF_PARAM(out_scratch),
+                                      temp_len + new_len - old_len);
+            if (unlikely(!new_buf)) { PFATAL("alloc"); }
+
+            /* Head */
+
+            memcpy(new_buf, out_buf, off);
+
+            /* Inserted part */
+
+            memcpy(new_buf + off, buf, new_len);
+
+            /* Tail */
+            memcpy(new_buf + off + new_len, out_buf + off2, temp_len - off2);
+
+            out_buf = new_buf;
+            afl_swap_bufs(AFL_BUF_PARAM(out), AFL_BUF_PARAM(out_scratch));
+            temp_len += (new_len - old_len);
+
+          }
+
+          // fprintf(stderr, "AFTER : %s\n", out_buf);
+          break;
+
+        }
+
+        case MUT_INSERTASCIINUM: {
+
+          u32 len = 1 + rand_below(afl, 8);
+          u32 pos = rand_below(afl, temp_len);
+          /* Insert ascii number. */
+          if (unlikely(temp_len < pos + len)) {
+
+            if (unlikely(temp_len < 8)) {
 
               break;
 
             } else {
 
-              r -= (r_cmp << 1);
+              goto retry_havoc_step;
 
             }
 
           }
 
-          /* Splicing otherwise if we are still here.
-             Overwrite bytes with a randomly selected chunk from another
-             testcase or insert that chunk. */
+#ifdef INTROSPECTION
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " INSERTASCIINUM_");
+          strcat(afl->mutation, afl->m_tmp);
+#endif
+          u64  val = rand_next(afl);
+          char buf[20];
+          snprintf(buf, sizeof(buf), "%llu", val);
+          memcpy(out_buf + pos, buf, len);
+
+          break;
+
+        }
+
+        case MUT_EXTRA_OVERWRITE: {
+
+          if (unlikely(!afl->extras_cnt)) { goto retry_havoc_step; }
+
+          /* Use the dictionary. */
+
+          u32 use_extra = rand_below(afl, afl->extras_cnt);
+          u32 extra_len = afl->extras[use_extra].len;
+
+          if (unlikely(extra_len > temp_len)) { goto retry_havoc_step; }
+
+          u32 insert_at = rand_below(afl, temp_len - extra_len + 1);
+#ifdef INTROSPECTION
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " EXTRA-OVERWRITE_%u_%u",
+                   insert_at, extra_len);
+          strcat(afl->mutation, afl->m_tmp);
+#endif
+          memcpy(out_buf + insert_at, afl->extras[use_extra].data, extra_len);
+
+          break;
+
+        }
+
+        case MUT_EXTRA_INSERT: {
+
+          if (unlikely(!afl->extras_cnt)) { goto retry_havoc_step; }
+
+          u32 use_extra = rand_below(afl, afl->extras_cnt);
+          u32 extra_len = afl->extras[use_extra].len;
+          if (unlikely(temp_len + extra_len >= MAX_FILE)) {
+
+            goto retry_havoc_step;
+
+          }
+
+          u8 *ptr = afl->extras[use_extra].data;
+          u32 insert_at = rand_below(afl, temp_len + 1);
+#ifdef INTROSPECTION
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " EXTRA-INSERT_%u_%u",
+                   insert_at, extra_len);
+          strcat(afl->mutation, afl->m_tmp);
+#endif
+
+          out_buf = afl_realloc(AFL_BUF_PARAM(out), temp_len + extra_len);
+          if (unlikely(!out_buf)) { PFATAL("alloc"); }
+
+          /* Tail */
+          memmove(out_buf + insert_at + extra_len, out_buf + insert_at,
+                  temp_len - insert_at);
+
+          /* Inserted part */
+          memcpy(out_buf + insert_at, ptr, extra_len);
+          temp_len += extra_len;
+
+          break;
+
+        }
+
+        case MUT_AUTO_EXTRA_OVERWRITE: {
+
+          if (unlikely(!afl->a_extras_cnt)) { goto retry_havoc_step; }
+
+          /* Use the dictionary. */
+
+          u32 use_extra = rand_below(afl, afl->a_extras_cnt);
+          u32 extra_len = afl->a_extras[use_extra].len;
+
+          if (unlikely(extra_len > temp_len)) { goto retry_havoc_step; }
+
+          u32 insert_at = rand_below(afl, temp_len - extra_len + 1);
+#ifdef INTROSPECTION
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp),
+                   " AUTO-EXTRA-OVERWRITE_%u_%u", insert_at, extra_len);
+          strcat(afl->mutation, afl->m_tmp);
+#endif
+          memcpy(out_buf + insert_at, afl->a_extras[use_extra].data, extra_len);
+
+          break;
+
+        }
+
+        case MUT_AUTO_EXTRA_INSERT: {
+
+          if (unlikely(!afl->a_extras_cnt)) { goto retry_havoc_step; }
+
+          u32 use_extra = rand_below(afl, afl->a_extras_cnt);
+          u32 extra_len = afl->a_extras[use_extra].len;
+          if (unlikely(temp_len + extra_len >= MAX_FILE)) {
+
+            goto retry_havoc_step;
+
+          }
+
+          u8 *ptr = afl->a_extras[use_extra].data;
+          u32 insert_at = rand_below(afl, temp_len + 1);
+#ifdef INTROSPECTION
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " AUTO-EXTRA-INSERT_%u_%u",
+                   insert_at, extra_len);
+          strcat(afl->mutation, afl->m_tmp);
+#endif
+
+          out_buf = afl_realloc(AFL_BUF_PARAM(out), temp_len + extra_len);
+          if (unlikely(!out_buf)) { PFATAL("alloc"); }
+
+          /* Tail */
+          memmove(out_buf + insert_at + extra_len, out_buf + insert_at,
+                  temp_len - insert_at);
+
+          /* Inserted part */
+          memcpy(out_buf + insert_at, ptr, extra_len);
+          temp_len += extra_len;
+
+          break;
+
+        }
+
+        case MUT_SPLICE_OVERWRITE: {
+
+          if (unlikely(afl->ready_for_splicing_count <= 1)) {
+
+            goto retry_havoc_step;
+
+          }
 
           /* Pick a random queue entry and seek to it. */
 
@@ -2880,79 +3171,110 @@ havoc_stage:
 
             tid = rand_below(afl, afl->queued_items);
 
-          } while (tid == afl->current_entry || afl->queue_buf[tid]->len < 4);
+          } while (unlikely(tid == afl->current_entry ||
+
+                            afl->queue_buf[tid]->len < 4));
 
           /* Get the testcase for splicing. */
           struct queue_entry *target = afl->queue_buf[tid];
           u32                 new_len = target->len;
           u8                 *new_buf = queue_testcase_get(afl, target);
 
-          if ((temp_len >= 2 && r % 2) || temp_len + HAVOC_BLK_XL >= MAX_FILE) {
-
-            /* overwrite mode */
+          /* overwrite mode */
 
-            u32 copy_from, copy_to, copy_len;
+          u32 copy_from, copy_to, copy_len;
 
-            copy_len = choose_block_len(afl, new_len - 1);
-            if (copy_len > temp_len) copy_len = temp_len;
+          copy_len = choose_block_len(afl, new_len - 1);
+          if (copy_len > temp_len) copy_len = temp_len;
 
-            copy_from = rand_below(afl, new_len - copy_len + 1);
-            copy_to = rand_below(afl, temp_len - copy_len + 1);
+          copy_from = rand_below(afl, new_len - copy_len + 1);
+          copy_to = rand_below(afl, temp_len - copy_len + 1);
 
 #ifdef INTROSPECTION
-            snprintf(afl->m_tmp, sizeof(afl->m_tmp),
-                     " SPLICE_OVERWRITE-%u-%u-%u-%s", copy_from, copy_to,
-                     copy_len, target->fname);
-            strcat(afl->mutation, afl->m_tmp);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp),
+                   " SPLICE-OVERWRITE_%u_%u_%u_%s", copy_from, copy_to,
+                   copy_len, target->fname);
+          strcat(afl->mutation, afl->m_tmp);
 #endif
-            memmove(out_buf + copy_to, new_buf + copy_from, copy_len);
+          memmove(out_buf + copy_to, new_buf + copy_from, copy_len);
 
-          } else {
+          break;
+
+        }
+
+        case MUT_SPLICE_INSERT: {
+
+          if (unlikely(afl->ready_for_splicing_count <= 1)) {
+
+            goto retry_havoc_step;
+
+          }
+
+          if (unlikely(temp_len + HAVOC_BLK_XL >= MAX_FILE)) {
+
+            goto retry_havoc_step;
+
+          }
+
+          /* Pick a random queue entry and seek to it. */
+
+          u32 tid;
+          do {
+
+            tid = rand_below(afl, afl->queued_items);
+
+          } while (unlikely(tid == afl->current_entry ||
+
+                            afl->queue_buf[tid]->len < 4));
 
-            /* insert mode */
+          /* Get the testcase for splicing. */
+          struct queue_entry *target = afl->queue_buf[tid];
+          u32                 new_len = target->len;
+          u8                 *new_buf = queue_testcase_get(afl, target);
 
-            u32 clone_from, clone_to, clone_len;
+          /* insert mode */
 
-            clone_len = choose_block_len(afl, new_len);
-            clone_from = rand_below(afl, new_len - clone_len + 1);
-            clone_to = rand_below(afl, temp_len + 1);
+          u32 clone_from, clone_to, clone_len;
 
-            u8 *temp_buf = afl_realloc(AFL_BUF_PARAM(out_scratch),
-                                       temp_len + clone_len + 1);
-            if (unlikely(!temp_buf)) { PFATAL("alloc"); }
+          clone_len = choose_block_len(afl, new_len);
+          clone_from = rand_below(afl, new_len - clone_len + 1);
+          clone_to = rand_below(afl, temp_len + 1);
+
+          u8 *temp_buf =
+              afl_realloc(AFL_BUF_PARAM(out_scratch), temp_len + clone_len + 1);
+          if (unlikely(!temp_buf)) { PFATAL("alloc"); }
 
 #ifdef INTROSPECTION
-            snprintf(afl->m_tmp, sizeof(afl->m_tmp),
-                     " SPLICE_INSERT-%u-%u-%u-%s", clone_from, clone_to,
-                     clone_len, target->fname);
-            strcat(afl->mutation, afl->m_tmp);
+          snprintf(afl->m_tmp, sizeof(afl->m_tmp), " SPLICE-INSERT_%u_%u_%u_%s",
+                   clone_from, clone_to, clone_len, target->fname);
+          strcat(afl->mutation, afl->m_tmp);
 #endif
-            /* Head */
+          /* Head */
 
-            memcpy(temp_buf, out_buf, clone_to);
+          memcpy(temp_buf, out_buf, clone_to);
 
-            /* Inserted part */
-
-            memcpy(temp_buf + clone_to, new_buf + clone_from, clone_len);
+          /* Inserted part */
 
-            /* Tail */
-            memcpy(temp_buf + clone_to + clone_len, out_buf + clone_to,
-                   temp_len - clone_to);
+          memcpy(temp_buf + clone_to, new_buf + clone_from, clone_len);
 
-            out_buf = temp_buf;
-            afl_swap_bufs(AFL_BUF_PARAM(out), AFL_BUF_PARAM(out_scratch));
-            temp_len += clone_len;
+          /* Tail */
+          memcpy(temp_buf + clone_to + clone_len, out_buf + clone_to,
+                 temp_len - clone_to);
 
-          }
+          out_buf = temp_buf;
+          afl_swap_bufs(AFL_BUF_PARAM(out), AFL_BUF_PARAM(out_scratch));
+          temp_len += clone_len;
 
           break;
 
-          // end of default
+        }
 
       }
 
     }
 
+    }
+
     if (common_fuzz_stuff(afl, out_buf, temp_len)) { goto abandon_entry; }
 
     /* out_buf might have been mangled a bit, so let's restore it to its
@@ -3038,7 +3360,9 @@ retry_splicing:
 
       tid = rand_below(afl, afl->queued_items);
 
-    } while (tid == afl->current_entry || afl->queue_buf[tid]->len < 4);
+    } while (
+
+        unlikely(tid == afl->current_entry || afl->queue_buf[tid]->len < 4));
 
     /* Get the testcase */
     afl->splicing_with = tid;
@@ -3078,6 +3402,25 @@ retry_splicing:
 
   ret_val = 0;
 
+#ifdef INTROSPECTION
+
+  afl->havoc_prof->queued_det_stage =
+      before_havoc_findings - before_det_findings;
+  afl->havoc_prof->queued_havoc_stage =
+      afl->queued_items - before_havoc_findings;
+  afl->havoc_prof->total_queued_det += afl->havoc_prof->queued_det_stage;
+  afl->havoc_prof->edge_det_stage = before_havoc_edges - before_det_edges;
+  afl->havoc_prof->edge_havoc_stage =
+      count_non_255_bytes(afl, afl->virgin_bits) - before_havoc_edges;
+  afl->havoc_prof->total_det_edge += afl->havoc_prof->edge_det_stage;
+  afl->havoc_prof->det_stage_time = before_havoc_time - before_det_time;
+  afl->havoc_prof->havoc_stage_time = get_cur_time() - before_havoc_time;
+  afl->havoc_prof->total_det_time += afl->havoc_prof->det_stage_time;
+
+  plot_profile_data(afl, afl->queue_cur);
+
+#endif
+
 /* we are through with this queue entry - for this iteration */
 abandon_entry:
 
@@ -3092,7 +3435,12 @@ abandon_entry:
     --afl->pending_not_fuzzed;
     afl->queue_cur->was_fuzzed = 1;
     afl->reinit_table = 1;
-    if (afl->queue_cur->favored) { --afl->pending_favored; }
+    if (afl->queue_cur->favored) {
+
+      --afl->pending_favored;
+      afl->smallest_favored = -1;
+
+    }
 
   }
 
@@ -3348,13 +3696,13 @@ static u8 mopt_common_fuzzing(afl_state_t *afl, MOpt_globals_t MOpt_globals) {
    * SIMPLE BITFLIP (+dictionary construction) *
    *********************************************/
 
-#define FLIP_BIT(_ar, _b)                   \
-  do {                                      \
-                                            \
-    u8 *_arf = (u8 *)(_ar);                 \
-    u32 _bf = (_b);                         \
-    _arf[(_bf) >> 3] ^= (128 >> ((_bf)&7)); \
-                                            \
+#define FLIP_BIT(_ar, _b)                     \
+  do {                                        \
+                                              \
+    u8 *_arf = (u8 *)(_ar);                   \
+    u32 _bf = (_b);                           \
+    _arf[(_bf) >> 3] ^= (128 >> ((_bf) & 7)); \
+                                              \
   } while (0)
 
   /* Single walking bit. */
@@ -5555,7 +5903,13 @@ pacemaker_fuzzing:
 
             --afl->pending_not_fuzzed;
             afl->queue_cur->was_fuzzed = 1;
-            if (afl->queue_cur->favored) { --afl->pending_favored; }
+            afl->reinit_table = 1
+            if (afl->queue_cur->favored) {
+
+              --afl->pending_favored;
+              afl->smallest_favored = -1;
+
+            }
 
           }