Memory: Reduced default maximum bitmap size from 24 to 18 and give a notice to use --bitmap-max to restore

docs/changes.txt

@@ -20,8 +20,10 @@
 ## Improvements
 ##
 
+- Memory: Reduced default maximum bitmap size from 24 to 18 and give a notice to use --bitmap-max to restore
 - Memory: Limit maximum host memory to allocate depending on bitness
-- Tests: Added hash-modes 11700 (Streebog-256) and 11800 (Streebog-512)
+- Tests: Added hash-mode 11700 (Streebog-256)
+- Tests: Added hash-mode 11800 (Streebog-512)
 - Tests: Added hash-mode 11850 (HMAC-Streebog-512 (key = $pass), big-endian)
 
 ##

include/types.h

@@ -92,6 +92,7 @@ typedef enum event_identifier
   EVENT_AUTOTUNE_STARTING         = 0x00000001,
   EVENT_BITMAP_INIT_POST          = 0x00000010,
   EVENT_BITMAP_INIT_PRE           = 0x00000011,
+  EVENT_BITMAP_FINAL_OVERFLOW     = 0x00000012,
   EVENT_CALCULATED_WORDS_BASE     = 0x00000020,
   EVENT_CRACKER_FINISHED          = 0x00000030,
   EVENT_CRACKER_HASH_CRACKED      = 0x00000031,
@@ -534,7 +535,7 @@ typedef enum user_options_defaults
   ATTACK_MODE              = ATTACK_MODE_STRAIGHT,
   BENCHMARK_ALL            = false,
   BENCHMARK                = false,
-  BITMAP_MAX               = 24,
+  BITMAP_MAX               = 18,
   BITMAP_MIN               = 16,
   #ifdef WITH_BRAIN
   BRAIN_CLIENT             = false,

src/bitmap.c

@@ -7,6 +7,7 @@
 #include "types.h"
 #include "memory.h"
 #include "bitmap.h"
+#include "event.h"
 
 static void selftest_to_bitmap (const u32 dgst_shifts, char *digests_buf_ptr, const u32 dgst_pos0, const u32 dgst_pos1, const u32 dgst_pos2, const u32 dgst_pos3, const u32 bitmap_mask, u32 *bitmap_a, u32 *bitmap_b, u32 *bitmap_c, u32 *bitmap_d)
 {
@@ -128,6 +129,11 @@ int bitmap_ctx_init (hashcat_ctx_t *hashcat_ctx)
     break;
   }
 
+  if (bitmap_bits == bitmap_max)
+  {
+    EVENT_DATA (EVENT_BITMAP_FINAL_OVERFLOW, NULL, 0);
+  }
+
   bitmap_nums = 1u << bitmap_bits;
 
   bitmap_mask = bitmap_nums - 1;

src/main.c

@@ -580,6 +580,20 @@ static void main_bitmap_init_post (MAYBE_UNUSED hashcat_ctx_t *hashcat_ctx, MAYB
   event_log_info_nn (hashcat_ctx, "Generated bitmap tables...");
 }
 
+static void main_bitmap_final_overflow (MAYBE_UNUSED hashcat_ctx_t *hashcat_ctx, MAYBE_UNUSED const void *buf, MAYBE_UNUSED const size_t len)
+{
+  const user_options_t *user_options = hashcat_ctx->user_options;
+
+  if (user_options->quiet == true) return;
+
+  event_log_advice (hashcat_ctx, "Bitmap table overflowed at %d bits.", user_options->bitmap_max);
+  event_log_advice (hashcat_ctx, "This typically happens with too many hashes and reduces your performance.");
+  event_log_advice (hashcat_ctx, "You can increase the bitmap table size with --bitmap-max, but");
+  event_log_advice (hashcat_ctx, "this creates a trade-off between L2-cache and bitmap efficiency.");
+  event_log_advice (hashcat_ctx, "It is therefore not guaranteed to restore full performance.");
+  event_log_advice (hashcat_ctx, NULL);
+}
+
 static void main_set_kernel_power_final (MAYBE_UNUSED hashcat_ctx_t *hashcat_ctx, MAYBE_UNUSED const void *buf, MAYBE_UNUSED const size_t len)
 {
   const user_options_t *user_options = hashcat_ctx->user_options;
@@ -954,6 +968,7 @@ static void event (const u32 id, hashcat_ctx_t *hashcat_ctx, const void *buf, co
   {
     case EVENT_BITMAP_INIT_POST:          main_bitmap_init_post          (hashcat_ctx, buf, len); break;
     case EVENT_BITMAP_INIT_PRE:           main_bitmap_init_pre           (hashcat_ctx, buf, len); break;
+    case EVENT_BITMAP_FINAL_OVERFLOW:     main_bitmap_final_overflow     (hashcat_ctx, buf, len); break;
     case EVENT_CALCULATED_WORDS_BASE:     main_calculated_words_base     (hashcat_ctx, buf, len); break;
     case EVENT_CRACKER_FINISHED:          main_cracker_finished          (hashcat_ctx, buf, len); break;
     case EVENT_CRACKER_HASH_CRACKED:      main_cracker_hash_cracked      (hashcat_ctx, buf, len); break;