Fixed race condition in potfile check during removal of empty hashes

docs/changes.txt

@@ -45,6 +45,7 @@
 - Fixed internal access on module option attribute OPTS_TYPE_SUGGEST_KG with the result that it was unused
 - Fixed invalid handling of outfile folder entries for -m 22000
 - Fixed password reassembling for cracked hashes on host for slow hashes in optimized mode that are longer than 32 characters
+- Fixed race condition in potfile check during removal of empty hashes
 - Fixed race condition resulting in out of memory error on startup if multiple hashcat instances are started at the same time
 - Fixed rare case of misalignment of the status prompt when other user warnings are shown within the hashcat output
 - Fixed too early execution of some module functions which could make use of non-final values opts_type and opti_type

include/hashes.h

@@ -27,6 +27,7 @@ int hashes_init_stage3    (hashcat_ctx_t *hashcat_ctx);
 int hashes_init_stage4    (hashcat_ctx_t *hashcat_ctx);
 int hashes_init_selftest  (hashcat_ctx_t *hashcat_ctx);
 int hashes_init_benchmark (hashcat_ctx_t *hashcat_ctx);
+int hashes_init_zerohash  (hashcat_ctx_t *hashcat_ctx);
 
 void hashes_destroy (hashcat_ctx_t *hashcat_ctx);
 

src/hashcat.c

@@ -508,6 +508,12 @@ static int outer_loop (hashcat_ctx_t *hashcat_ctx)
     EVENT (EVENT_POTFILE_REMOVE_PARSE_POST);
   }
 
+  /**
+   * zero hash removes
+   */
+
+  if (hashes_init_zerohash (hashcat_ctx) == -1) return -1;
+
   /**
    * load hashes, stage 3, update cracked results from potfile
    */

src/hashes.c

@@ -2048,6 +2048,79 @@ int hashes_init_benchmark (hashcat_ctx_t *hashcat_ctx)
   return 0;
 }
 
+int hashes_init_zerohash (hashcat_ctx_t *hashcat_ctx)
+{
+  const hashconfig_t   *hashconfig   = hashcat_ctx->hashconfig;
+  const hashes_t       *hashes       = hashcat_ctx->hashes;
+  const module_ctx_t   *module_ctx   = hashcat_ctx->module_ctx;
+
+  // do not use this unless really needed, for example as in LM
+
+  if (module_ctx->module_hash_decode_zero_hash == MODULE_DEFAULT) return 0;
+
+  hash_t *hashes_buf = hashes->hashes_buf;
+  u32     hashes_cnt = hashes->hashes_cnt;
+
+  // no solution for these special hash types (for instane because they use hashfile in output etc)
+
+  hash_t hash_buf;
+
+  hash_buf.digest    = hcmalloc (hashconfig->dgst_size);
+  hash_buf.salt      = NULL;
+  hash_buf.esalt     = NULL;
+  hash_buf.hook_salt = NULL;
+  hash_buf.cracked   = 0;
+  hash_buf.hash_info = NULL;
+  hash_buf.pw_buf    = NULL;
+  hash_buf.pw_len    = 0;
+
+  if (hashconfig->is_salted == true)
+  {
+    hash_buf.salt = (salt_t *) hcmalloc (sizeof (salt_t));
+  }
+
+  if (hashconfig->esalt_size > 0)
+  {
+    hash_buf.esalt = hcmalloc (hashconfig->esalt_size);
+  }
+
+  if (hashconfig->hook_salt_size > 0)
+  {
+    hash_buf.hook_salt = hcmalloc (hashconfig->hook_salt_size);
+  }
+
+  module_ctx->module_hash_decode_zero_hash (hashconfig, hash_buf.digest, hash_buf.salt, hash_buf.esalt, hash_buf.hook_salt, hash_buf.hash_info);
+
+  hash_t *found = (hash_t *) hc_bsearch_r (&hash_buf, hashes_buf, hashes_cnt, sizeof (hash_t), sort_by_hash_no_salt, (void *) hashconfig);
+
+  if (found != NULL)
+  {
+    found->pw_buf = (char *) hcmalloc (1);
+    found->pw_len = 0;
+
+    found->cracked = 1;
+  }
+
+  if (hashconfig->esalt_size > 0)
+  {
+    hcfree (hash_buf.esalt);
+  }
+
+  if (hashconfig->hook_salt_size > 0)
+  {
+    hcfree (hash_buf.hook_salt);
+  }
+
+  if (hashconfig->is_salted == true)
+  {
+    hcfree (hash_buf.salt);
+  }
+
+  hcfree (hash_buf.digest);
+
+  return 0;
+}
+
 void hashes_destroy (hashcat_ctx_t *hashcat_ctx)
 {
   hashconfig_t   *hashconfig   = hashcat_ctx->hashconfig;

src/main.c

@@ -411,12 +411,12 @@ static void main_potfile_num_cracked (MAYBE_UNUSED hashcat_ctx_t *hashcat_ctx, M
   {
     if (potfile_remove_cracks == 1)
     {
-      event_log_info (hashcat_ctx, "INFO: Removed 1 hash found in potfile.");
+      event_log_info (hashcat_ctx, "INFO: Removed 1 hash found as as potfile entry or as empty hash.");
       event_log_info (hashcat_ctx, NULL);
     }
     else
     {
-      event_log_info (hashcat_ctx, "INFO: Removed %d hashes found in potfile.", potfile_remove_cracks);
+      event_log_info (hashcat_ctx, "INFO: Removed %d hashes found as potfile entries or as empty hash.", potfile_remove_cracks);
       event_log_info (hashcat_ctx, NULL);
     }
   }

src/potfile.c

@@ -498,24 +498,6 @@ int potfile_remove_parse (hashcat_ctx_t *hashcat_ctx)
     }
   }
 
-  // do not use this unless really needed, for example as in LM
-
-  if (module_ctx->module_hash_decode_zero_hash != MODULE_DEFAULT)
-  {
-    module_ctx->module_hash_decode_zero_hash (hashconfig, hash_buf.digest, hash_buf.salt, hash_buf.esalt, hash_buf.hook_salt, hash_buf.hash_info);
-
-    if (hashconfig->potfile_keep_all_hashes == true)
-    {
-      potfile_update_hashes (hashcat_ctx, &hash_buf, NULL, 0, all_hashes_tree);
-    }
-    else
-    {
-      hash_t *found = (hash_t *) hc_bsearch_r (&hash_buf, hashes_buf, hashes_cnt, sizeof (hash_t), sort_by_hash_no_salt, (void *) hashconfig);
-
-      potfile_update_hash (hashcat_ctx, found, NULL, 0);
-    }
-  }
-
   const int rc = potfile_read_open (hashcat_ctx);
 
   if (rc == -1) return -1;