Merge branch 'replay' into tmp

docs/env_variables.md

@@ -424,6 +424,15 @@ checks or alter some of the more exotic semantics of the tool:
   - Setting `AFL_FORCE_UI` will force painting the UI on the screen even if
     no valid terminal was detected (for virtual consoles)
 
+  - If you are using persistent mode (you should, see [instrumentation/README.persistent_mode.md](instrumentation/README.persistent_mode.md))
+    some targets keep inherent state due which a detected crash testcase does
+    not crash the target again when the testcase is given. To be able to still
+    re-trigger these crashes you can use the `AFL_PERSISTENT_RECORD` variable
+    with a value of how many previous fuzz cases to keep prio a crash.
+    if set to e.g. 10, then the 9 previous inputs are written to
+    out/default/crashes as RECORD:000000,cnt:000000 to RECORD:000000,cnt:000008
+    and RECORD:000000,cnt:000009 being the crash case.
+
   - If you are Jakub, you may need `AFL_I_DONT_CARE_ABOUT_MISSING_CRASHES`.
     Others need not apply, unless they also want to disable the
     `/proc/sys/kernel/core_pattern` check.

include/afl-fuzz.h

@@ -390,7 +390,7 @@ typedef struct afl_env_vars {
       *afl_hang_tmout, *afl_forksrv_init_tmout, *afl_skip_crashes, *afl_preload,
       *afl_max_det_extras, *afl_statsd_host, *afl_statsd_port,
       *afl_crash_exitcode, *afl_statsd_tags_flavor, *afl_testcache_size,
-      *afl_testcache_entries, *afl_kill_signal, *afl_target_env;
+      *afl_testcache_entries, *afl_kill_signal, *afl_target_env, *afl_persistent_record;
 
 } afl_env_vars_t;
 

include/config.h

@@ -73,6 +73,15 @@
 
 /* Now non-cmplog configuration options */
 
+
+/* If a persistent target keeps state and found crashes are not reproducable
+   then enable this option and set the AFL_PERSISTENT_RECORD env variable
+   to a number. These number of testcases prior the crash will be kept and
+   also written to the crash/ directory */
+
+#define AFL_PERSISTENT_RECORD
+
+
 /* console output colors: There are three ways to configure its behavior
  * 1. default: colored outputs fixed on: defined USE_COLOR && defined
  * ALWAYS_COLORED The env var. AFL_NO_COLOR will have no effect

include/envs.h

@@ -130,6 +130,7 @@ static char *afl_environment_variables[] = {
     "AFL_PASSTHROUGH",
     "AFL_PATH",
     "AFL_PERFORMANCE_FILE",
+    "AFL_PERSISTENT_RECORD",
     "AFL_PRELOAD",
     "AFL_TARGET_ENV",
     "AFL_PYTHON_MODULE",

include/forkserver.h

@@ -94,6 +94,15 @@ typedef struct afl_forkserver {
 
   char *cmplog_binary;                  /* the name of the cmplog binary    */
 
+  /* persistent mode replay functionality */
+  u32   persistent_record;              /* persistent replay setting        */
+  u32   persistent_record_idx;          /* persistent replay cache ptr      */
+  u32   persistent_record_cnt;          /* persistent replay counter        */
+  u8 *  persistent_record_dir;
+  u8 ** persistent_record_data;
+  u32 * persistent_record_len;
+  s32   persistent_record_pid;
+
   /* Function to kick off the forkserver child */
   void (*init_child_func)(struct afl_forkserver *fsrv, char **argv);
 

src/afl-forkserver.c

@@ -42,6 +42,7 @@
 #include <errno.h>
 #include <signal.h>
 #include <fcntl.h>
+#include <limits.h>
 #include <sys/time.h>
 #include <sys/wait.h>
 #include <sys/resource.h>
@@ -126,7 +127,7 @@ void afl_fsrv_init_dup(afl_forkserver_t *fsrv_to, afl_forkserver_t *from) {
   fsrv_to->last_run_timed_out = 0;
 
   fsrv_to->init_child_func = from->init_child_func;
-  // Note: do not copy ->add_extra_func
+  // Note: do not copy ->add_extra_func or ->persistent_record*
 
   list_append(&fsrv_list, fsrv_to);
 
@@ -364,6 +365,23 @@ void afl_fsrv_start(afl_forkserver_t *fsrv, char **argv,
 
   if (!be_quiet) { ACTF("Spinning up the fork server..."); }
 
+#ifdef AFL_PERSISTENT_RECORD
+  if (unlikely(fsrv->persistent_record)) {
+
+    fsrv->persistent_record_data =
+        (u8 **)ck_alloc(fsrv->persistent_record * sizeof(u8 *));
+    fsrv->persistent_record_len =
+        (u32 *)ck_alloc(fsrv->persistent_record * sizeof(u32));
+
+    if (!fsrv->persistent_record_data || !fsrv->persistent_record_len) {
+
+      FATAL("Unable to allocate memory for persistent replay.");
+
+    }
+
+  }
+#endif
+
   if (fsrv->use_fauxsrv) {
 
     /* TODO: Come up with some nice way to initialize this all */
@@ -1032,6 +1050,31 @@ u32 afl_fsrv_get_mapsize(afl_forkserver_t *fsrv, char **argv,
 
 void afl_fsrv_write_to_testcase(afl_forkserver_t *fsrv, u8 *buf, size_t len) {
 
+#ifdef AFL_PERSISTENT_RECORD
+  if (unlikely(fsrv->persistent_record)) {
+
+    fsrv->persistent_record_len[fsrv->persistent_record_idx] = len;
+    fsrv->persistent_record_data[fsrv->persistent_record_idx] = afl_realloc(
+        (void **)&fsrv->persistent_record_data[fsrv->persistent_record_idx],
+        len);
+
+    if (unlikely(!fsrv->persistent_record_data[fsrv->persistent_record_idx])) {
+
+      FATAL("allocating replay memory failed.");
+
+    }
+
+    memcpy(fsrv->persistent_record_data[fsrv->persistent_record_idx], buf, len);
+
+    if (unlikely(++fsrv->persistent_record_idx >= fsrv->persistent_record)) {
+
+      fsrv->persistent_record_idx = 0;
+
+    }
+
+  }
+#endif
+
   if (likely(fsrv->use_shmem_fuzz && fsrv->shmem_fuzz)) {
 
     if (unlikely(len > MAX_FILE)) len = MAX_FILE;
@@ -1146,6 +1189,25 @@ fsrv_run_result_t afl_fsrv_run_target(afl_forkserver_t *fsrv, u32 timeout,
 
   }
 
+#ifdef AFL_PERSISTENT_RECORD
+  // end of persistent loop?
+  if (unlikely(fsrv->persistent_record &&
+               fsrv->persistent_record_pid != fsrv->child_pid)) {
+
+    fsrv->persistent_record_pid = fsrv->child_pid;
+    u32 idx, val;
+    if (unlikely(!fsrv->persistent_record_idx))
+      idx = fsrv->persistent_record - 1;
+    else
+      idx = fsrv->persistent_record_idx - 1;
+    val = fsrv->persistent_record_len[idx];
+    memset((void *)fsrv->persistent_record_len, 0,
+           fsrv->persistent_record * sizeof(u32));
+    fsrv->persistent_record_len[idx] = val;
+
+  }
+#endif
+
   if (fsrv->child_pid <= 0) {
 
     if (*stop_soon_p) { return 0; }
@@ -1244,6 +1306,38 @@ fsrv_run_result_t afl_fsrv_run_target(afl_forkserver_t *fsrv, u32 timeout,
           (fsrv->uses_crash_exitcode &&
            WEXITSTATUS(fsrv->child_status) == fsrv->crash_exitcode))) {
 
+#ifdef AFL_PERSISTENT_RECORD
+    if (unlikely(fsrv->persistent_record)) {
+
+      char fn[PATH_MAX];
+      u32  i, writecnt = 0;
+      for (i = 0; i < fsrv->persistent_record; ++i) {
+
+        u32 entry = (i + fsrv->persistent_record_idx) % fsrv->persistent_record;
+        u8 *data = fsrv->persistent_record_data[entry];
+        u32 len = fsrv->persistent_record_len[entry];
+        if (likely(len && data)) {
+
+          snprintf(fn, sizeof(fn), "%s/RECORD:%06u,cnt:%06u",
+                   fsrv->persistent_record_dir, fsrv->persistent_record_cnt,
+                   writecnt++);
+          int fd = open(fn, O_CREAT | O_TRUNC | O_WRONLY, 0644);
+          if (fd >= 0) {
+
+            ck_write(fd, data, len, fn);
+            close(fd);
+
+          }
+
+        }
+
+      }
+
+      ++fsrv->persistent_record_cnt;
+
+    }
+#endif
+
     /* For a proper crash, set last_kill_signal to WTERMSIG, else set it to 0 */
     fsrv->last_kill_signal =
         WIFSIGNALED(fsrv->child_status) ? WTERMSIG(fsrv->child_status) : 0;

src/afl-fuzz-state.c

@@ -292,6 +292,13 @@ void read_afl_environment(afl_state_t *afl, char **envp) {
             afl->afl_env.afl_autoresume =
                 get_afl_env(afl_environment_variables[i]) ? 1 : 0;
 
+          } else if (!strncmp(env, "AFL_PERSISTENT_RECORD",
+
+                              afl_environment_variable_len)) {
+
+            afl->afl_env.afl_persistent_record =
+                get_afl_env(afl_environment_variables[i]);
+
           } else if (!strncmp(env, "AFL_CYCLE_SCHEDULES",
 
                               afl_environment_variable_len)) {

src/afl-fuzz.c

@@ -222,6 +222,9 @@ static void usage(u8 *argv0, int more_help) {
       "AFL_PATH: path to AFL support binaries\n"
       "AFL_PYTHON_MODULE: mutate and trim inputs with the specified Python module\n"
       "AFL_QUIET: suppress forkserver status messages\n"
+#ifdef AFL_PERSISTENT_RECORD
+      "AFL_PERSISTENT_RECORD: record the last X inputs to every crash in out/crashes\n"
+#endif
       "AFL_PRELOAD: LD_PRELOAD / DYLD_INSERT_LIBRARIES settings for target\n"
       "AFL_TARGET_ENV: pass extra environment variables to target\n"
       "AFL_SHUFFLE_QUEUE: reorder the input queue randomly on startup\n"
@@ -253,7 +256,13 @@ static void usage(u8 *argv0, int more_help) {
   SAYF("Compiled with %s module support, see docs/custom_mutator.md\n",
        (char *)PYTHON_VERSION);
 #else
-  SAYF("Compiled without python module support\n");
+  SAYF("Compiled without python module support.\n");
+#endif
+
+#ifdef AFL_PERSISTENT_RECORD
+  SAYF("Compiled with AFL_PERSISTENT_RECORD support.\n");
+#else
+  SAYF("Compiled without AFL_PERSISTENT_RECORD support.\n");
 #endif
 
 #ifdef USEMMAP
@@ -263,27 +272,27 @@ static void usage(u8 *argv0, int more_help) {
 #endif
 
 #ifdef ASAN_BUILD
-  SAYF("Compiled with ASAN_BUILD\n\n");
+  SAYF("Compiled with ASAN_BUILD.\n");
 #endif
 
 #ifdef NO_SPLICING
-  SAYF("Compiled with NO_SPLICING\n\n");
+  SAYF("Compiled with NO_SPLICING.\n");
 #endif
 
 #ifdef PROFILING
-  SAYF("Compiled with PROFILING\n\n");
+  SAYF("Compiled with PROFILING.\n");
 #endif
 
 #ifdef INTROSPECTION
-  SAYF("Compiled with INTROSPECTION\n\n");
+  SAYF("Compiled with INTROSPECTION.\n");
 #endif
 
 #ifdef _DEBUG
-  SAYF("Compiled with _DEBUG\n\n");
+  SAYF("Compiled with _DEBUG.\n");
 #endif
 
 #ifdef _AFL_DOCUMENT_MUTATIONS
-  SAYF("Compiled with _AFL_DOCUMENT_MUTATIONS\n\n");
+  SAYF("Compiled with _AFL_DOCUMENT_MUTATIONS.\n");
 #endif
 
   SAYF("For additional help please consult %s/README.md :)\n\n", doc_path);
@@ -1023,6 +1032,28 @@ int main(int argc, char **argv_orig, char **envp) {
 
   }
 
+  if (unlikely(afl->afl_env.afl_persistent_record)) {
+
+#ifdef AFL_PERSISTENT_RECORD
+
+    afl->fsrv.persistent_record = atoi(afl->afl_env.afl_persistent_record);
+
+    if (afl->fsrv.persistent_record < 2) {
+
+      FATAL(
+          "AFL_PERSISTENT_RECORD value must be be at least 2, recommended is "
+          "100 or 1000.");
+
+    }
+
+#else
+
+    FATAL("afl-fuzz was not compiled with AFL_PERSISTENT_RECORD enabled in config.h!");
+
+#endif
+
+  }
+
   if (afl->fsrv.mem_limit && afl->shm.cmplog_mode) afl->fsrv.mem_limit += 260;
 
   OKF("afl++ is maintained by Marc \"van Hauser\" Heuse, Heiko \"hexcoder\" "
@@ -1489,6 +1520,20 @@ int main(int argc, char **argv_orig, char **envp) {
 
   check_binary(afl, argv[optind]);
 
+  if (unlikely(afl->fsrv.persistent_record)) {
+
+    if (!getenv(PERSIST_ENV_VAR)) {
+
+      FATAL(
+          "Target binary is not compiled in persistent mode, "
+          "AFL_PERSISTENT_RECORD makes no sense.");
+
+    }
+
+    afl->fsrv.persistent_record_dir = alloc_printf("%s/crashes", afl->out_dir);
+
+  }
+
   if (afl->shmem_testcase_mode) { setup_testcase_shmem(afl); }
 
   afl->start_time = get_cur_time();