Merge pull request #601 from Rumata888/fixing_symcc

Fixing symcc custom mutator

custom_mutators/symcc/symcc.c

@@ -1,7 +1,10 @@
+#define _GNU_SOURCE
 #include <stdio.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
 #include "config.h"
 #include "debug.h"
 #include "afl-fuzz.h"
@@ -21,6 +24,7 @@ typedef struct my_mutator {
   afl_state_t *afl;
   u8 *         mutator_buf;
   u8 *         out_dir;
+  u8 *         tmp_dir;
   u8 *         target;
   uint32_t     seed;
 
@@ -55,10 +59,11 @@ my_mutator_t *afl_custom_init(afl_state_t *afl, unsigned int seed) {
   if (!(data->out_dir = getenv("SYMCC_OUTPUT_DIR"))) {
 
     data->out_dir = alloc_printf("%s/symcc", afl->out_dir);
-    setenv("SYMCC_OUTPUT_DIR", data->out_dir, 1);
 
   }
 
+  data->tmp_dir = alloc_printf("%s/tmp", data->out_dir);
+  setenv("SYMCC_OUTPUT_DIR", data->tmp_dir, 1);
   int pid = fork();
 
   if (pid == -1) return NULL;
@@ -84,6 +89,10 @@ my_mutator_t *afl_custom_init(afl_state_t *afl, unsigned int seed) {
 
   if (mkdir(data->out_dir, 0755))
     PFATAL("Could not create directory %s", data->out_dir);
+
+  if (mkdir(data->tmp_dir, 0755))
+    PFATAL("Could not create directory %s", data->tmp_dir);
+
   DBG("out_dir=%s, target=%s\n", data->out_dir, data->target);
 
   return data;
@@ -96,33 +105,119 @@ void afl_custom_queue_new_entry(my_mutator_t * data,
                                 const uint8_t *filename_new_queue,
                                 const uint8_t *filename_orig_queue) {
 
+  int         pipefd[2];
+  struct stat st;
+  ACTF("Queueing to symcc: %s", filename_new_queue);
+  u8 *fn = alloc_printf("%s", filename_new_queue);
+  if (!(stat(fn, &st) == 0 && S_ISREG(st.st_mode) && st.st_size)) {
+
+    ck_free(fn);
+    PFATAL("Couldn't find enqueued file: %s", fn);
+
+  }
+
+  if (afl_struct->fsrv.use_stdin) {
+
+    if (pipe(pipefd) == -1) {
+
+      ck_free(fn);
+      PFATAL("Couldn't create a pipe for interacting with symcc child process");
+
+    }
+
+  }
+
   int pid = fork();
 
   if (pid == -1) return;
 
-  if (pid) pid = waitpid(pid, NULL, 0);
-
-  if (pid == 0) {
-
-    setenv("SYMCC_INPUT_FILE", afl_struct->fsrv.out_file, 1);
+  if (pid) {
 
     if (afl_struct->fsrv.use_stdin) {
 
-      u8 *fn = alloc_printf("%s/%s", afl_struct->out_dir, filename_new_queue);
+      close(pipefd[0]);
       int fd = open(fn, O_RDONLY);
 
       if (fd >= 0) {
 
         ssize_t r = read(fd, data->mutator_buf, MAX_FILE);
-        close(fd);
         DBG("fn=%s, fd=%d, size=%ld\n", fn, fd, r);
-        if (r <= 0) return;
-        close(0);
-        ck_write(0, data->mutator_buf, r, fn);
         ck_free(fn);
+        close(fd);
+        if (r <= 0) {
+
+          close(pipefd[1]);
+          return;
+
+        }
+
+        if (r > fcntl(pipefd[1], F_GETPIPE_SZ))
+          fcntl(pipefd[1], F_SETPIPE_SZ, MAX_FILE);
+        ck_write(pipefd[1], data->mutator_buf, r, filename_new_queue);
+
+      } else {
+
+        ck_free(fn);
+        close(pipefd[1]);
+        PFATAL(
+            "Something happened to the enqueued file before sending its "
+            "contents to symcc binary");
 
       }
 
+      close(pipefd[1]);
+
+    }
+
+    pid = waitpid(pid, NULL, 0);
+
+    // At this point we need to transfer files to output dir, since their names
+    // collide and symcc will just overwrite them
+
+    struct dirent **nl;
+    int32_t         items = scandir(data->tmp_dir, &nl, NULL, NULL);
+    u8 *            origin_name = basename(filename_new_queue);
+    int32_t         i;
+    if (items > 0) {
+
+      for (i = 0; i < (u32)items; ++i) {
+
+        struct stat st;
+        u8 *source_name = alloc_printf("%s/%s", data->tmp_dir, nl[i]->d_name);
+        u8 *destination_name =
+            alloc_printf("%s/%s.%s", data->out_dir, origin_name, nl[i]->d_name);
+        DBG("test=%s\n", fn);
+        if (stat(source_name, &st) == 0 && S_ISREG(st.st_mode) && st.st_size) {
+
+          rename(source_name, destination_name);
+          DBG("found=%s\n", source_name);
+
+        }
+
+        ck_free(source_name);
+        ck_free(destination_name);
+        free(nl[i]);
+
+      }
+
+      free(nl);
+
+    }
+
+  }
+
+  if (pid == 0) {
+
+    if (afl_struct->fsrv.use_stdin) {
+
+      unsetenv("SYMCC_INPUT_FILE");
+      close(pipefd[1]);
+      dup2(pipefd[0], 0);
+
+    } else {
+
+      setenv("SYMCC_INPUT_FILE", afl_struct->fsrv.out_file, 1);
+
     }
 
     DBG("exec=%s\n", data->target);
@@ -130,6 +225,7 @@ void afl_custom_queue_new_entry(my_mutator_t * data,
     close(2);
     dup2(afl_struct->fsrv.dev_null_fd, 1);
     dup2(afl_struct->fsrv.dev_null_fd, 2);
+
     execvp(data->target, afl_struct->argv);
     DBG("exec=FAIL\n");
     exit(-1);
@@ -180,7 +276,7 @@ size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size,
 
   struct dirent **nl;
   int32_t         i, done = 0, items = scandir(data->out_dir, &nl, NULL, NULL);
-  size_t          size = 0;
+  ssize_t         size = 0;
 
   if (items <= 0) return 0;
 
@@ -199,6 +295,7 @@ size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size,
 
           size = read(fd, data->mutator_buf, max_size);
           *out_buf = data->mutator_buf;
+
           close(fd);
           done = 1;
 
@@ -217,7 +314,7 @@ size_t afl_custom_fuzz(my_mutator_t *data, uint8_t *buf, size_t buf_size,
 
   free(nl);
   DBG("FUZZ size=%lu\n", size);
-  return size;
+  return (uint32_t)size;
 
 }