Merge pull request #461 from AFLplusplus/new_splicing

New splicing

1 files changed, 142 insertions, 539 deletions

diff --git a/src/afl-fuzz-one.c b/src/afl-fuzz-one.c
index 9e54815c..399bfcab 100644
--- a/src/afl-fuzz-one.c
+++ b/src/afl-fuzz-one.c
@@ -24,11 +24,6 @@
  */
 
 #include "afl-fuzz.h"
-#include <string.h>
-
-static u8 *strnstr(const u8 *s, const u8 *find, size_t slen);
-static u32 string_replace(u8 **out_buf, s32 *temp_len, u32 pos, u8 *from,
-                          u8 *to);
 
 /* MOpt */
 
@@ -367,463 +362,6 @@ static void locate_diffs(u8 *ptr1, u8 *ptr2, u32 len, s32 *first, s32 *last) {
 
 #endif                                                     /* !IGNORE_FINDS */
 
-/* Not pretty, but saves a lot of writing */
-#define BUF_PARAMS(name) (void **)&afl->name##_buf, &afl->name##_size
-
-static u8 *strnstr(const u8 *s, const u8 *find, size_t slen) {
-
-  char   c, sc;
-  size_t len;
-
-  if ((c = *find++) != '\0') {
-
-    len = strlen(find);
-    do {
-
-      do {
-
-        if (slen-- < 1 || (sc = *s++) == '\0') return (NULL);
-
-      } while (sc != c);
-
-      if (len > slen) return (NULL);
-
-    } while (strncmp(s, find, len) != 0);
-
-    s--;
-
-  }
-
-  return ((u8 *)s);
-
-}
-
-/* replace between deliminators, if rep == NULL, then we will duplicate the
- * target */
-
-static u32 delim_replace(u8 **out_buf, s32 *temp_len, size_t pos,
-                         const u8 *ldelim, const u8 *rdelim, u8 *rep) {
-
-  u8 *end_buf = *out_buf + *temp_len;
-  u8 *ldelim_start = strnstr(*out_buf + pos, ldelim, *temp_len - pos);
-
-  if (ldelim_start != NULL) {
-
-    u32 max = (end_buf - ldelim_start - 1 > AFL_TXT_STRING_MAX_LEN
-                   ? AFL_TXT_STRING_MAX_LEN
-                   : end_buf - ldelim_start - 1);
-
-    if (max > 0) {
-
-      u8 *rdelim_end = strnstr(ldelim_start + 1, rdelim, max);
-
-      if (rdelim_end != NULL) {
-
-        u32 rep_len, delim_space_len = rdelim_end - ldelim_start - 1, xtra = 0;
-
-        if (rep != NULL) {
-
-          rep_len = (u32)strlen(rep);
-
-        } else {  // NULL? then we copy the value in between the delimiters
-
-          rep_len = delim_space_len;
-          delim_space_len = 0;
-          rep = ldelim_start + 1;
-          xtra = rep_len;
-
-        }
-
-        if (rep_len != delim_space_len) {
-
-          memmove(ldelim_start + rep_len + xtra + 1, rdelim_end,
-                  *temp_len - (rdelim_end - *out_buf));
-
-        }
-
-        memcpy(ldelim_start + 1, rep, rep_len);
-        *temp_len = (*temp_len - delim_space_len + rep_len);
-
-        return 1;
-
-      }
-
-    }
-
-  }
-
-  return 0;
-
-}
-
-static u32 delim_swap(u8 **out_buf, s32 *temp_len, size_t pos, const u8 *ldelim,
-                      const u8 *mdelim, const u8 *rdelim) {
-
-  u8 *out_buf_end = *out_buf + *temp_len;
-  u32 max = (*temp_len - pos > AFL_TXT_STRING_MAX_LEN ? AFL_TXT_STRING_MAX_LEN
-                                                      : *temp_len - pos);
-  u8 *ldelim_start = strnstr(*out_buf + pos, ldelim, max);
-
-  if (ldelim_start != NULL) {
-
-    max = (out_buf_end - ldelim_start - 1 > AFL_TXT_STRING_MAX_LEN
-               ? AFL_TXT_STRING_MAX_LEN
-               : out_buf_end - ldelim_start - 1);
-    if (max > 1) {
-
-      u8 *mdelim_pos = strnstr(ldelim_start + 1, mdelim, max);
-
-      if (mdelim_pos != NULL) {
-
-        max = (out_buf_end - mdelim_pos - 1 > AFL_TXT_STRING_MAX_LEN
-                   ? AFL_TXT_STRING_MAX_LEN
-                   : out_buf_end - mdelim_pos - 1);
-        if (max > 0) {
-
-          u8 *rdelim_end = strnstr(mdelim + 1, rdelim, max);
-
-          if (rdelim_end != NULL) {
-
-            u32 first_len = mdelim_pos - ldelim_start - 1;
-            u32 second_len = rdelim_end - mdelim_pos - 1;
-            u8  scratch[AFL_TXT_STRING_MAX_LEN];
-
-            memcpy(scratch, ldelim_start + 1, first_len);
-
-            if (first_len != second_len) {
-
-              memmove(ldelim_start + second_len + 1, mdelim_pos,
-                      out_buf_end - mdelim_pos);
-
-            }
-
-            memcpy(ldelim_start + 1, mdelim_pos + 1, second_len);
-
-            if (first_len != second_len) {
-
-              memmove(mdelim_pos + first_len + 1, rdelim_end,
-                      out_buf_end - rdelim_end);
-
-            }
-
-            memcpy(mdelim_pos + 1, scratch, first_len);
-
-            return 1;
-
-          }
-
-        }
-
-      }
-
-    }
-
-  }
-
-  return 0;
-
-}
-
-static u32 string_replace(u8 **out_buf, s32 *temp_len, u32 pos, u8 *from,
-                          u8 *to) {
-
-  u8 *start = strnstr(*out_buf + pos, from, *temp_len - pos);
-
-  if (start) {
-
-    u32 from_len = strlen(from);
-    u32 to_len = strlen(to);
-
-    if (from_len != to_len) {
-
-      memmove(start + to_len, start + from_len,
-              *temp_len - from_len - (start - *out_buf));
-
-    }
-
-    memcpy(start, to, to_len);
-    *temp_len = (*temp_len - from_len + to_len);
-
-    return 1;
-
-  }
-
-  return 0;
-
-}
-
-/* Returns 1 if a mutant was generated and placed in out_buf, 0 if none
- * generated. */
-
-static int text_mutation(afl_state_t *afl, u8 **out_buf, s32 *orig_temp_len) {
-
-  s32 temp_len;
-  u32 pos, yes = 0,
-           mutations = rand_below(afl, AFL_TXT_STRING_MAX_MUTATIONS) + 1;
-  u8 *new_buf = ck_maybe_grow(BUF_PARAMS(out_scratch),
-                              *orig_temp_len + AFL_TXT_STRING_MAX_MUTATIONS);
-  temp_len = *orig_temp_len;
-  memcpy(new_buf, *out_buf, temp_len);
-
-  for (u32 i = 0; i < mutations; i++) {
-
-    if (temp_len < AFL_TXT_MIN_LEN) {
-
-      if (yes)
-        return 1;
-      else
-        return 0;
-
-    }
-
-    pos = rand_below(afl, temp_len - 1);
-    int choice = rand_below(afl, 76);
-    switch (choice) {
-
-      case 0:
-        yes += string_replace(out_buf, &temp_len, pos, "*", " ");
-        break;
-      case 1:
-        yes += string_replace(out_buf, &temp_len, pos, "(", "(!");
-        break;
-      case 2:
-        yes += string_replace(out_buf, &temp_len, pos, "==", "!=");
-        break;
-      case 3:
-        yes += string_replace(out_buf, &temp_len, pos, "!=", "==");
-        break;
-      case 4:
-        yes += string_replace(out_buf, &temp_len, pos, "==", "<");
-        break;
-      case 5:
-        yes += string_replace(out_buf, &temp_len, pos, "<", "==");
-        break;
-      case 6:
-        yes += string_replace(out_buf, &temp_len, pos, "==", ">");
-        break;
-      case 7:
-        yes += string_replace(out_buf, &temp_len, pos, ">", "==");
-        break;
-      case 8:
-        yes += string_replace(out_buf, &temp_len, pos, "=", "<");
-        break;
-      case 9:
-        yes += string_replace(out_buf, &temp_len, pos, "=", ">");
-        break;
-      case 10:
-        yes += string_replace(out_buf, &temp_len, pos, "<", ">");
-        break;
-      case 11:
-        yes += string_replace(out_buf, &temp_len, pos, ">", "<");
-        break;
-      case 12:
-        yes += string_replace(out_buf, &temp_len, pos, "++", "--");
-        break;
-      case 13:
-        yes += string_replace(out_buf, &temp_len, pos, "--", "++");
-        break;
-      case 14:
-        yes += string_replace(out_buf, &temp_len, pos, "+", "-");
-        break;
-      case 15:
-        yes += string_replace(out_buf, &temp_len, pos, "+", "*");
-        break;
-      case 16:
-        yes += string_replace(out_buf, &temp_len, pos, "+", "/");
-        break;
-      case 17:
-        yes += string_replace(out_buf, &temp_len, pos, "+", "%");
-        break;
-      case 18:
-        yes += string_replace(out_buf, &temp_len, pos, "*", "-");
-        break;
-      case 19:
-        yes += string_replace(out_buf, &temp_len, pos, "*", "+");
-        break;
-      case 20:
-        yes += string_replace(out_buf, &temp_len, pos, "*", "/");
-        break;
-      case 21:
-        yes += string_replace(out_buf, &temp_len, pos, "*", "%");
-        break;
-      case 22:
-        yes += string_replace(out_buf, &temp_len, pos, "-", "+");
-        break;
-      case 23:
-        yes += string_replace(out_buf, &temp_len, pos, "-", "*");
-        break;
-      case 24:
-        yes += string_replace(out_buf, &temp_len, pos, "-", "/");
-        break;
-      case 25:
-        yes += string_replace(out_buf, &temp_len, pos, "-", "%");
-        break;
-      case 26:
-        yes += string_replace(out_buf, &temp_len, pos, "/", "-");
-        break;
-      case 27:
-        yes += string_replace(out_buf, &temp_len, pos, "/", "*");
-        break;
-      case 28:
-        yes += string_replace(out_buf, &temp_len, pos, "/", "+");
-        break;
-      case 29:
-        yes += string_replace(out_buf, &temp_len, pos, "/", "%");
-        break;
-      case 30:
-        yes += string_replace(out_buf, &temp_len, pos, "%", "-");
-        break;
-      case 31:
-        yes += string_replace(out_buf, &temp_len, pos, "%", "*");
-        break;
-      case 32:
-        yes += string_replace(out_buf, &temp_len, pos, "%", "/");
-        break;
-      case 33:
-        yes += string_replace(out_buf, &temp_len, pos, "%", "+");
-        break;
-      case 34:
-        yes += string_replace(out_buf, &temp_len, pos, "->", ".");
-        break;
-      case 35:
-        yes += string_replace(out_buf, &temp_len, pos, ".", "->");
-        break;
-      case 36:
-        yes += string_replace(out_buf, &temp_len, pos, "0", "1");
-        break;
-      case 37:
-        yes += string_replace(out_buf, &temp_len, pos, "1", "0");
-        break;
-      case 38:
-        yes += string_replace(out_buf, &temp_len, pos, "if", "while");
-        break;
-      case 39:
-        yes += string_replace(out_buf, &temp_len, pos, "while", "if");
-        break;
-      case 40:
-        yes += string_replace(out_buf, &temp_len, pos, "!", " ");
-        break;
-      case 41:
-        yes += string_replace(out_buf, &temp_len, pos, "&&", "||");
-        break;
-      case 42:
-        yes += string_replace(out_buf, &temp_len, pos, "||", "&&");
-        break;
-      case 43:
-        yes += string_replace(out_buf, &temp_len, pos, "!", "");
-        break;
-      case 44:
-        yes += string_replace(out_buf, &temp_len, pos, "==", "=");
-        break;
-      case 45:
-        yes += string_replace(out_buf, &temp_len, pos, "--", "");
-        break;
-      case 46:
-        yes += string_replace(out_buf, &temp_len, pos, "<<", "<");
-        break;
-      case 47:
-        yes += string_replace(out_buf, &temp_len, pos, ">>", ">");
-        break;
-      case 48:
-        yes += string_replace(out_buf, &temp_len, pos, "<", "<<");
-        break;
-      case 49:
-        yes += string_replace(out_buf, &temp_len, pos, ">", ">>");
-        break;
-      case 50:
-        yes += string_replace(out_buf, &temp_len, pos, "\"", "'");
-        break;
-      case 51:
-        yes += string_replace(out_buf, &temp_len, pos, "'", "\"");
-        break;
-      case 52:
-        yes += string_replace(out_buf, &temp_len, pos, "(", "\"");
-        break;
-      case 53:
-        yes += string_replace(out_buf, &temp_len, pos, "\n", " ");
-        break;
-      case 54:
-        yes += string_replace(out_buf, &temp_len, pos, "\n", ";");
-        break;
-      case 55:
-        yes += string_replace(out_buf, &temp_len, pos, "\n", "<");
-        break;
-      case 56:  /* Remove a semicolon delimited statement after a semicolon */
-        yes += delim_replace(out_buf, &temp_len, pos, ";", ";", ";");
-        break;
-      case 57: /* Remove a semicolon delimited statement after a left curly
-                  brace */
-        yes += delim_replace(out_buf, &temp_len, pos, "}", ";", "}");
-        break;
-      case 58:                            /* Remove a curly brace construct */
-        yes += delim_replace(out_buf, &temp_len, pos, "{", "}", "");
-        break;
-      case 59:         /* Replace a curly brace construct with an empty one */
-        yes += delim_replace(out_buf, &temp_len, pos, "{", "}", "{}");
-        break;
-      case 60:
-        yes += delim_swap(out_buf, &temp_len, pos, ";", ";", ";");
-        break;
-      case 61:
-        yes += delim_swap(out_buf, &temp_len, pos, "}", ";", ";");
-        break;
-      case 62:                        /* Swap comma delimited things case 1 */
-        yes += delim_swap(out_buf, &temp_len, pos, "(", ",", ")");
-        break;
-      case 63:                        /* Swap comma delimited things case 2 */
-        yes += delim_swap(out_buf, &temp_len, pos, "(", ",", ",");
-        break;
-      case 64:                        /* Swap comma delimited things case 3 */
-        yes += delim_swap(out_buf, &temp_len, pos, ",", ",", ",");
-        break;
-      case 65:                        /* Swap comma delimited things case 4 */
-        yes += delim_swap(out_buf, &temp_len, pos, ",", ",", ")");
-        break;
-      case 66:                                        /* Just delete a line */
-        yes += delim_replace(out_buf, &temp_len, pos, "\n", "\n", "");
-        break;
-      case 67:                      /* Delete something like "const" case 1 */
-        yes += delim_replace(out_buf, &temp_len, pos, " ", " ", "");
-        break;
-      case 68:                      /* Delete something like "const" case 2 */
-        yes += delim_replace(out_buf, &temp_len, pos, "\n", " ", "");
-        break;
-      case 69:                      /* Delete something like "const" case 3 */
-        yes += delim_replace(out_buf, &temp_len, pos, "(", " ", "");
-        break;
-      case 70:                        /* Swap space delimited things case 1 */
-        yes += delim_swap(out_buf, &temp_len, pos, " ", " ", " ");
-        break;
-      case 71:                        /* Swap space delimited things case 2 */
-        yes += delim_swap(out_buf, &temp_len, pos, " ", " ", ")");
-        break;
-      case 72:                        /* Swap space delimited things case 3 */
-        yes += delim_swap(out_buf, &temp_len, pos, "(", " ", " ");
-        break;
-      case 73:                        /* Swap space delimited things case 4 */
-        yes += delim_swap(out_buf, &temp_len, pos, "(", " ", ")");
-        break;
-      case 74:                           /* Duplicate a single line of code */
-        yes += delim_replace(out_buf, &temp_len, pos, "\n", "\n", NULL);
-        break;
-      case 75:  /* Duplicate a construct (most often, a non-nested for loop */
-        yes += delim_replace(out_buf, &temp_len, pos, "\n", "}", NULL);
-        break;
-
-    }
-
-  }
-
-  if (yes == 0 || temp_len <= 0) { return 0; }
-
-  swap_bufs(BUF_PARAMS(out), BUF_PARAMS(out_scratch));
-  *out_buf = new_buf;
-  *orig_temp_len = temp_len;
-
-  return 1;
-
-}
-
 /* Take the current entry from the queue, fuzz it for a while. This
    function is a tad too long... returns 0 if fuzzed successfully, 1 if
    skipped or bailed out. */
@@ -840,6 +378,9 @@ u8 fuzz_one_original(afl_state_t *afl) {
   u8  a_collect[MAX_AUTO_EXTRA];
   u32 a_len = 0;
 
+/* Not pretty, but saves a lot of writing */
+#define BUF_PARAMS(name) (void **)&afl->name##_buf, &afl->name##_size
+
 #ifdef IGNORE_FINDS
 
   /* In IGNORE_FINDS mode, skip any entries that weren't in the
@@ -2313,12 +1854,9 @@ havoc_stage:
   /* We essentially just do several thousand runs (depending on perf_score)
      where we take the input file and make random stacked tweaks. */
 
-  u32 r_max = 15 + ((afl->extras_cnt + afl->a_extras_cnt) ? 2 : 0) +
-              (afl->queue_cur->is_ascii ? AFL_TXT_BIAS : 0);
-
   for (afl->stage_cur = 0; afl->stage_cur < afl->stage_max; ++afl->stage_cur) {
 
-    u32 r, use_stacking = 1 << (1 + rand_below(afl, HAVOC_STACK_POW2));
+    u32 use_stacking = 1 << (1 + rand_below(afl, HAVOC_STACK_POW2));
 
     afl->stage_cur_val = use_stacking;
 
@@ -2358,9 +1896,8 @@ havoc_stage:
 
       }
 
-    retry_havoc:
-
-      switch ((r = rand_below(afl, r_max))) {
+      switch (rand_below(
+          afl, 16 + ((afl->extras_cnt + afl->a_extras_cnt) ? 2 : 0))) {
 
         case 0:
 
@@ -2654,98 +2191,177 @@ havoc_stage:
           break;
 
         }
+        
+        case 15: {
 
-          // TODO: add splicing mutation here.
-          // 15:
-          //     break;
+          /* Overwrite bytes with a randomly selected chunk from another
+             testcase or insert that chunk. */
 
-        default:
-          if (r == 15 && (afl->extras_cnt || afl->a_extras_cnt)) {
+          if (afl->queued_paths < 2) break;
 
-            /* Values 15 and 16 can be selected only if there are any extras
-               present in the dictionaries. */
+          /* Pick a random queue entry and seek to it. */
 
-            /* Overwrite bytes with an extra. */
+          u32 tid;
+          do
+            tid = rand_below(afl, afl->queued_paths);
+          while (tid == afl->current_entry);
 
-            if (!afl->extras_cnt || (afl->a_extras_cnt && rand_below(afl, 2))) {
+          struct queue_entry* target = afl->queue_buf[tid];
 
-              /* No user-specified extras or odds in our favor. Let's use an
-                 auto-detected one. */
+          /* Make sure that the target has a reasonable length. */
 
-              u32 use_extra = rand_below(afl, afl->a_extras_cnt);
-              u32 extra_len = afl->a_extras[use_extra].len;
-              u32 insert_at;
+          while (target && (target->len < 2 || target == afl->queue_cur))
+            target = target->next;
 
-              if (extra_len > temp_len) { break; }
+          if (!target) break;
 
-              insert_at = rand_below(afl, temp_len - extra_len + 1);
-              memcpy(out_buf + insert_at, afl->a_extras[use_extra].data,
-                     extra_len);
+          /* Read the testcase into a new buffer. */
 
-            } else {
+          fd = open(target->fname, O_RDONLY);
 
-              /* No auto extras or odds in our favor. Use the dictionary. */
+          if (unlikely(fd < 0)) { PFATAL("Unable to open '%s'", target->fname); }
 
-              u32 use_extra = rand_below(afl, afl->extras_cnt);
-              u32 extra_len = afl->extras[use_extra].len;
-              u32 insert_at;
+          u32 new_len = target->len;
+          u8 * new_buf = ck_maybe_grow(BUF_PARAMS(in_scratch), new_len);
 
-              if (extra_len > temp_len) { break; }
+          ck_read(fd, new_buf, new_len, target->fname);
 
-              insert_at = rand_below(afl, temp_len - extra_len + 1);
-              memcpy(out_buf + insert_at, afl->extras[use_extra].data,
-                     extra_len);
+          close(fd);
 
-            }
+          u8 overwrite = 0;
+          if (temp_len >= 2 && rand_below(afl, 2))
+            overwrite = 1;
+          else if (temp_len + HAVOC_BLK_XL >= MAX_FILE) {
+            if (temp_len >= 2) overwrite = 1;
+            else break;
+          }
 
-          } else if (r == 16 && (afl->extras_cnt || afl->a_extras_cnt)) {
+          if (overwrite) {
 
-            u32 use_extra, extra_len, insert_at = rand_below(afl, temp_len + 1);
-            u8 *ptr;
+            u32 copy_from, copy_to, copy_len;
 
-            /* Insert an extra. Do the same dice-rolling stuff as for the
-               previous case. */
+            copy_len = choose_block_len(afl, new_len - 1);
+            if (copy_len > temp_len) copy_len = temp_len;
 
-            if (!afl->extras_cnt || (afl->a_extras_cnt && rand_below(afl, 2))) {
+            copy_from = rand_below(afl, new_len - copy_len + 1);
+            copy_to = rand_below(afl, temp_len - copy_len + 1);
 
-              use_extra = rand_below(afl, afl->a_extras_cnt);
-              extra_len = afl->a_extras[use_extra].len;
-              ptr = afl->a_extras[use_extra].data;
+            memmove(out_buf + copy_to, new_buf + copy_from, copy_len);
 
-            } else {
+          } else {
+          
+            u32 clone_from, clone_to, clone_len;
+            
+            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);
+
+            u8 * temp_buf =
+                ck_maybe_grow(BUF_PARAMS(out_scratch), temp_len + clone_len);
 
-              use_extra = rand_below(afl, afl->extras_cnt);
-              extra_len = afl->extras[use_extra].len;
-              ptr = afl->extras[use_extra].data;
+            /* Head */
 
-            }
+            memcpy(temp_buf, out_buf, clone_to);
 
-            if (temp_len + extra_len >= MAX_FILE) { break; }
+            /* Inserted part */
 
-            out_buf = ck_maybe_grow(BUF_PARAMS(out), temp_len + extra_len);
+            memcpy(temp_buf + clone_to, new_buf + clone_from, clone_len);
 
             /* Tail */
-            memmove(out_buf + insert_at + extra_len, out_buf + insert_at,
-                    temp_len - insert_at);
+            memcpy(temp_buf + clone_to + clone_len, out_buf + clone_to,
+                   temp_len - clone_to);
 
-            /* Inserted part */
-            memcpy(out_buf + insert_at, ptr, extra_len);
+            swap_bufs(BUF_PARAMS(out), BUF_PARAMS(out_scratch));
+            out_buf = temp_buf;
+            temp_len += clone_len;
+          
+          }
+
+          break;
+
+        }
 
-            temp_len += extra_len;
+          /* Values 15 and 16 can be selected only if there are any extras
+             present in the dictionaries. */
+
+        case 16: {
+
+          /* Overwrite bytes with an extra. */
+
+          if (!afl->extras_cnt || (afl->a_extras_cnt && rand_below(afl, 2))) {
+
+            /* No user-specified extras or odds in our favor. Let's use an
+               auto-detected one. */
+
+            u32 use_extra = rand_below(afl, afl->a_extras_cnt);
+            u32 extra_len = afl->a_extras[use_extra].len;
+            u32 insert_at;
+
+            if (extra_len > temp_len) { break; }
+
+            insert_at = rand_below(afl, temp_len - extra_len + 1);
+            memcpy(out_buf + insert_at, afl->a_extras[use_extra].data,
+                   extra_len);
 
           } else {
 
-            // ascii mutations
-            if (text_mutation(afl, &out_buf, &temp_len) == 0) goto retry_havoc;
+            /* No auto extras or odds in our favor. Use the dictionary. */
+
+            u32 use_extra = rand_below(afl, afl->extras_cnt);
+            u32 extra_len = afl->extras[use_extra].len;
+            u32 insert_at;
 
-            //#ifdef _AFL_DOCUMENT_MUTATIONS
-            //            fprintf(stderr, "MUTATED: %s/mutations/%09u:*\n",
-            //            afl->out_dir,
-            //                    afl->document_counter);
-            //#endif
+            if (extra_len > temp_len) { break; }
+
+            insert_at = rand_below(afl, temp_len - extra_len + 1);
+            memcpy(out_buf + insert_at, afl->extras[use_extra].data, extra_len);
 
           }
 
+          break;
+
+        }
+
+        case 17: {
+
+          u32 use_extra, extra_len, insert_at = rand_below(afl, temp_len + 1);
+          u8 *ptr;
+
+          /* Insert an extra. Do the same dice-rolling stuff as for the
+             previous case. */
+
+          if (!afl->extras_cnt || (afl->a_extras_cnt && rand_below(afl, 2))) {
+
+            use_extra = rand_below(afl, afl->a_extras_cnt);
+            extra_len = afl->a_extras[use_extra].len;
+            ptr = afl->a_extras[use_extra].data;
+
+          } else {
+
+            use_extra = rand_below(afl, afl->extras_cnt);
+            extra_len = afl->extras[use_extra].len;
+            ptr = afl->extras[use_extra].data;
+
+          }
+
+          if (temp_len + extra_len >= MAX_FILE) { break; }
+
+          out_buf = ck_maybe_grow(BUF_PARAMS(out), temp_len + extra_len);
+
+          /* 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;
+
+        }
+
       }
 
     }
@@ -2831,20 +2447,7 @@ retry_splicing:
     } while (tid == afl->current_entry);
 
     afl->splicing_with = tid;
-    target = afl->queue;
-
-    while (tid >= 100) {
-
-      target = target->next_100;
-      tid -= 100;
-
-    }
-
-    while (tid--) {
-
-      target = target->next;
-
-    }
+    target = afl->queue_buf[tid];
 
     /* Make sure that the target has a reasonable length. */