From 4e2adc031a49ac36cb9749b9aeeb4da3799a6d2d Mon Sep 17 00:00:00 2001
From: jsteube <jens.steube@gmail.com>
Date: Thu, 23 Feb 2017 10:39:17 +0100
Subject: [PATCH] Add some compiler independant integer overflow functions

---
 include/shared.h |  6 ++++--
 src/mpsp.c       |  2 +-
 src/shared.c     | 42 +++++++++++++++++++++++++++++++++++-------
 src/wordlist.c   |  8 ++++----
 4 files changed, 44 insertions(+), 14 deletions(-)

diff --git a/include/shared.h b/include/shared.h
index 583682186..3e1968cb7 100644
--- a/include/shared.h
+++ b/include/shared.h
@@ -13,8 +13,10 @@
 #include <time.h>
 #include <fcntl.h>
 
-bool overflow_check_int64_add (const u64 a, const u64 b);
-bool overflow_check_int64_mul (const u64 a, const u64 b);
+bool overflow_check_u32_add (const u32 a, const u32 b);
+bool overflow_check_u32_mul (const u32 a, const u32 b);
+bool overflow_check_u64_add (const u64 a, const u64 b);
+bool overflow_check_u64_mul (const u64 a, const u64 b);
 
 bool is_power_of_2 (const u32 v);
 
diff --git a/src/mpsp.c b/src/mpsp.c
index f08c9680f..3f5e29506 100644
--- a/src/mpsp.c
+++ b/src/mpsp.c
@@ -815,7 +815,7 @@ static int sp_get_sum (u32 start, u32 stop, cs_t *root_css_buf, u64 *result)
 
   for (i = start; i < stop; i++)
   {
-    if (overflow_check_int64_mul (sum, root_css_buf[i].cs_len) == true) return -1;
+    if (overflow_check_u64_mul (sum, root_css_buf[i].cs_len) == false) return -1;
 
     sum *= root_css_buf[i].cs_len;
   }
diff --git a/src/shared.c b/src/shared.c
index 15ad31001..e3f696eca 100644
--- a/src/shared.c
+++ b/src/shared.c
@@ -7,18 +7,46 @@
 #include "types.h"
 #include "shared.h"
 
-bool overflow_check_int64_add (const u64 a, const u64 b)
+static inline int get_msb32 (const u32 v)
 {
-  u64 t;
-
-  return __builtin_add_overflow (a, b, &t);
+  return 32 - __builtin_clz (v);
 }
 
-bool overflow_check_int64_mul (const u64 a, const u64 b)
+static inline int get_msb64 (const u64 v)
 {
-  u64 t;
+  return 64 - __builtin_clzll (v);
+}
 
-  return __builtin_mul_overflow (a, b, &t);
+bool overflow_check_u32_add (const u32 a, const u32 b)
+{
+  const int a_msb = get_msb32 (a);
+  const int b_msb = get_msb32 (b);
+
+  return ((a_msb < 32) && (b_msb < 32));
+}
+
+bool overflow_check_u32_mul (const u32 a, const u32 b)
+{
+  const int a_msb = get_msb32 (a);
+  const int b_msb = get_msb32 (b);
+
+  return ((a_msb + b_msb) < 32);
+}
+
+bool overflow_check_u64_add (const u64 a, const u64 b)
+{
+  const int a_msb = get_msb64 (a);
+  const int b_msb = get_msb64 (b);
+
+  return ((a_msb < 64) && (b_msb < 64));
+}
+
+bool overflow_check_u64_mul (const u64 a, const u64 b)
+{
+  const int a_msb = get_msb64 (a);
+  const int b_msb = get_msb64 (b);
+
+  return ((a_msb + b_msb) < 64);
 }
 
 bool is_power_of_2 (const u32 v)
diff --git a/src/wordlist.c b/src/wordlist.c
index 0d991c7d4..9e2137ca1 100644
--- a/src/wordlist.c
+++ b/src/wordlist.c
@@ -305,13 +305,13 @@ int count_words (hashcat_ctx_t *hashcat_ctx, FILE *fd, const char *dictfile, u64
 
       if (user_options_extra->attack_kern == ATTACK_KERN_STRAIGHT)
       {
-        if (overflow_check_int64_mul (keyspace, (u64) straight_ctx->kernel_rules_cnt) == true) return -1;
+        if (overflow_check_u64_mul (keyspace, straight_ctx->kernel_rules_cnt) == false) return -1;
 
         keyspace *= straight_ctx->kernel_rules_cnt;
       }
       else if (user_options_extra->attack_kern == ATTACK_KERN_COMBI)
       {
-        if (overflow_check_int64_mul (keyspace, combinator_ctx->combs_cnt) == true) return -1;
+        if (overflow_check_u64_mul (keyspace, combinator_ctx->combs_cnt) == false) return -1;
 
         keyspace *= combinator_ctx->combs_cnt;
       }
@@ -378,13 +378,13 @@ int count_words (hashcat_ctx_t *hashcat_ctx, FILE *fd, const char *dictfile, u64
       {
         if (user_options_extra->attack_kern == ATTACK_KERN_STRAIGHT)
         {
-          if (overflow_check_int64_add (cnt, (u64) straight_ctx->kernel_rules_cnt) == true) return -1;
+          if (overflow_check_u64_add (cnt, straight_ctx->kernel_rules_cnt) == false) return -1;
 
           cnt += straight_ctx->kernel_rules_cnt;
         }
         else if (user_options_extra->attack_kern == ATTACK_KERN_COMBI)
         {
-          if (overflow_check_int64_add (cnt, combinator_ctx->combs_cnt) == true) return -1;
+          if (overflow_check_u64_add (cnt, combinator_ctx->combs_cnt) == false) return -1;
 
           cnt += combinator_ctx->combs_cnt;
         }