From 8e00ef9a88b5d16d294679a54ecf96e28ff68c99 Mon Sep 17 00:00:00 2001
From: Gabriele Gristina <matrix@users.noreply.github.com>
Date: Sat, 26 Feb 2022 19:14:20 +0100
Subject: [PATCH 1/5] Added support to use 'John the Ripper' hash format with
 hash-type 13100

---
 docs/changes.txt           |   1 +
 src/modules/module_13100.c | 170 +++++++++++++++++++++++++++----------
 2 files changed, 124 insertions(+), 47 deletions(-)

diff --git a/docs/changes.txt b/docs/changes.txt
index 4f7ef789b..d799a42c1 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -18,6 +18,7 @@
 - Added support to building universal macOS binary on Apple Silicon
 - Added hex encoding format for --separator option
 - Added password candidates range to --status-json output
+- Added support to use 'John the Ripper' hash format with hash-type 13100
 
 ##
 ## Bugs
diff --git a/src/modules/module_13100.c b/src/modules/module_13100.c
index 23bec5483..8806d37ec 100644
--- a/src/modules/module_13100.c
+++ b/src/modules/module_13100.c
@@ -48,9 +48,11 @@ typedef struct krb5tgs
   u32 edata2[5120];
   u32 edata2_len;
 
+  u32 format;
+
 } krb5tgs_t;
 
-static const char *SIGNATURE_KRB5TGS = "$krb5tgs$23$";
+static const char *SIGNATURE_KRB5TGS = "$krb5tgs$";
 
 char *module_jit_build_options (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSED const user_options_t *user_options, MAYBE_UNUSED const user_options_extra_t *user_options_extra, MAYBE_UNUSED const hashes_t *hashes, MAYBE_UNUSED const hc_device_param_t *device_param)
 {
@@ -117,33 +119,90 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
   token.signatures_cnt    = 1;
   token.signatures_buf[0] = SIGNATURE_KRB5TGS;
 
-  token.len[0]  = 12;
+  token.len[0]  = 9;
   token.attr[0] = TOKEN_ATTR_FIXED_LENGTH
                 | TOKEN_ATTR_VERIFY_SIGNATURE;
 
   /**
-   * $krb5tgs$23$checksum$edata2
-   * $krb5tgs$23$*user*realm*spn*$checksum$edata2
+   * hc
+   * format 1: $krb5tgs$23$*user*realm*spn*$checksum$edata2
+   * format 2: $krb5tgs$23$checksum$edata2
+   *
+   * jtr
+   * format 3: $krb5tgs$spn$checksum$edata2
    */
 
-  if (line_len < 16) return (PARSER_SALT_LENGTH);
+  if (line_len < 9) return (PARSER_SALT_LENGTH);
 
-  if (line_buf[12] == '*')
+  if (line_buf[9] == '2' && line_buf[10] == '3' && line_buf[11] == '$')
   {
-    char *account_info_start = (char *) line_buf + 12; // we want the * char included
-    char *account_info_stop  = strchr ((const char *) account_info_start + 1, '*');
+    if (line_buf[12] == '*')
+    {
+      char *account_info_start = (char *) line_buf + 12; // we want the * char included
+
+      char *account_info_stop  = strchr ((const char *) account_info_start + 1, '*');
+
+      if (account_info_stop == NULL) return (PARSER_SEPARATOR_UNMATCHED);
+
+      account_info_stop++; // we want the * char included
+      account_info_stop++; // we want the $ char included
+
+      const int account_info_len = account_info_stop - account_info_start;
 
-    if (account_info_stop == NULL) return (PARSER_SEPARATOR_UNMATCHED);
+      token.token_cnt  = 5;
 
-    account_info_stop++; // we want the * char included
-    account_info_stop++; // we want the $ char included
+      token.sep[1]     = '$';
+      token.len_min[1] = 2;
+      token.len_max[1] = 2;
+      token.attr[1]    = TOKEN_ATTR_VERIFY_LENGTH
+                       | TOKEN_ATTR_VERIFY_DIGIT;
 
-    const int account_info_len = account_info_stop - account_info_start;
+      token.len[2]     = account_info_len;
+      token.attr[2]    = TOKEN_ATTR_FIXED_LENGTH;
 
+      token.sep[3]     = '$';
+      token.len_min[3] = 32;
+      token.len_max[3] = 32;
+      token.attr[3]    = TOKEN_ATTR_VERIFY_LENGTH
+                       | TOKEN_ATTR_VERIFY_HEX;
+
+      token.sep[4]     = '$';
+      token.len_min[4] = 64;
+      token.len_max[4] = 40960;
+      token.attr[4]    = TOKEN_ATTR_VERIFY_LENGTH
+                       | TOKEN_ATTR_VERIFY_HEX;
+    }
+    else
+    {
+      token.token_cnt  = 4;
+
+      token.sep[1]     = '$';
+      token.len_min[1] = 2;
+      token.len_max[1] = 2;
+      token.attr[1]    = TOKEN_ATTR_VERIFY_LENGTH
+                       | TOKEN_ATTR_VERIFY_DIGIT;
+
+      token.sep[2]     = '$';
+      token.len_min[2] = 32;
+      token.len_max[2] = 32;
+      token.attr[2]    = TOKEN_ATTR_VERIFY_LENGTH
+                       | TOKEN_ATTR_VERIFY_HEX;
+
+      token.sep[3]     = '$';
+      token.len_min[3] = 64;
+      token.len_max[3] = 40960;
+      token.attr[3]    = TOKEN_ATTR_VERIFY_LENGTH
+                       | TOKEN_ATTR_VERIFY_HEX;
+    }
+  }
+  else
+  {
     token.token_cnt  = 4;
 
-    token.len[1]     = account_info_len;
-    token.attr[1]    = TOKEN_ATTR_FIXED_LENGTH;
+    token.sep[1]     = ':';
+    token.len_min[1] = 0;
+    token.len_max[1] = 2048;
+    token.attr[1]    = TOKEN_ATTR_VERIFY_LENGTH;
 
     token.sep[2]     = '$';
     token.len_min[2] = 32;
@@ -157,22 +216,6 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
     token.attr[3]    = TOKEN_ATTR_VERIFY_LENGTH
                      | TOKEN_ATTR_VERIFY_HEX;
   }
-  else
-  {
-    token.token_cnt  = 3;
-
-    token.sep[1]     = '$';
-    token.len_min[1] = 32;
-    token.len_max[1] = 32;
-    token.attr[1]    = TOKEN_ATTR_VERIFY_LENGTH
-                     | TOKEN_ATTR_VERIFY_HEX;
-
-    token.sep[2]     = '$';
-    token.len_min[2] = 64;
-    token.len_max[2] = 40960;
-    token.attr[2]    = TOKEN_ATTR_VERIFY_LENGTH
-                     | TOKEN_ATTR_VERIFY_HEX;
-  }
 
   const int rc_tokenizer = input_tokenizer ((const u8 *) line_buf, line_len, &token);
 
@@ -183,23 +226,38 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
   int data_len;
 
-  if (line_buf[12] == '*')
+  if (line_buf[9] == '2' && line_buf[10] == '3' && line_buf[11] == '$')
   {
-    checksum_pos = token.buf[2];
+    if (line_buf[12] == '*')
+    {
+      checksum_pos = token.buf[3];
 
-    data_pos = token.buf[3];
-    data_len = token.len[3];
+      data_pos = token.buf[4];
+      data_len = token.len[4];
 
-    memcpy (krb5tgs->account_info, token.buf[1], token.len[1]);
+      memcpy (krb5tgs->account_info, token.buf[2], token.len[2]);
+      krb5tgs->format = 1;
+    }
+    else
+    {
+      checksum_pos = token.buf[2];
+
+      data_pos = token.buf[3];
+      data_len = token.len[3];
+
+      krb5tgs->account_info[0] = 0;
+      krb5tgs->format = 2;
+    }
   }
   else
   {
-    checksum_pos = token.buf[1];
+    checksum_pos = token.buf[2];
 
-    data_pos = token.buf[2];
-    data_len = token.len[2];
+    data_pos = token.buf[3];
+    data_len = token.len[3];
 
-    krb5tgs->account_info[0] = 0;
+    memcpy (krb5tgs->account_info, token.buf[1], token.len[1]);
+    krb5tgs->format = 3;
   }
 
   krb5tgs->checksum[0] = hex_to_u32 (checksum_pos +  0);
@@ -251,14 +309,32 @@ int module_hash_encode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
     sprintf (data + j, "%02x", ptr_edata2[i]);
   }
 
-  const int line_len = snprintf (line_buf, line_size, "%s%s%08x%08x%08x%08x$%s",
-    SIGNATURE_KRB5TGS,
-    (char *) krb5tgs->account_info,
-    byte_swap_32 (krb5tgs->checksum[0]),
-    byte_swap_32 (krb5tgs->checksum[1]),
-    byte_swap_32 (krb5tgs->checksum[2]),
-    byte_swap_32 (krb5tgs->checksum[3]),
-    data);
+  int line_len;
+
+  // preserve the input hash format
+
+  if (krb5tgs->format != 3) // hc
+  {
+    line_len = snprintf (line_buf, line_size, "%s23$%s%08x%08x%08x%08x$%s",
+      SIGNATURE_KRB5TGS,
+      (char *) krb5tgs->account_info,
+      byte_swap_32 (krb5tgs->checksum[0]),
+      byte_swap_32 (krb5tgs->checksum[1]),
+      byte_swap_32 (krb5tgs->checksum[2]),
+      byte_swap_32 (krb5tgs->checksum[3]),
+      data);
+  }
+  else // jtr
+  {
+    line_len = snprintf (line_buf, line_size, "%s%s:%08x%08x%08x%08x$%s",
+      SIGNATURE_KRB5TGS,
+      (char *) krb5tgs->account_info,
+      byte_swap_32 (krb5tgs->checksum[0]),
+      byte_swap_32 (krb5tgs->checksum[1]),
+      byte_swap_32 (krb5tgs->checksum[2]),
+      byte_swap_32 (krb5tgs->checksum[3]),
+      data);
+  }
 
   return line_len;
 }

From ca9656e9836f7a60bd68d9a0b126600ca7a1c1b7 Mon Sep 17 00:00:00 2001
From: Gabriele Gristina <matrix@users.noreply.github.com>
Date: Sat, 26 Feb 2022 19:39:23 +0100
Subject: [PATCH 2/5] Updated krb5tgs struct on 13100 kernels

---
 OpenCL/m13100_a0-optimized.cl | 1 +
 OpenCL/m13100_a0-pure.cl      | 1 +
 OpenCL/m13100_a1-optimized.cl | 1 +
 OpenCL/m13100_a1-pure.cl      | 1 +
 OpenCL/m13100_a3-optimized.cl | 1 +
 OpenCL/m13100_a3-pure.cl      | 1 +
 src/modules/module_13100.c    | 1 -
 7 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/OpenCL/m13100_a0-optimized.cl b/OpenCL/m13100_a0-optimized.cl
index 0d67fb3c9..a2b653f47 100644
--- a/OpenCL/m13100_a0-optimized.cl
+++ b/OpenCL/m13100_a0-optimized.cl
@@ -25,6 +25,7 @@ typedef struct krb5tgs
   u32 checksum[4];
   u32 edata2[5120];
   u32 edata2_len;
+  u32 format;
 
 } krb5tgs_t;
 
diff --git a/OpenCL/m13100_a0-pure.cl b/OpenCL/m13100_a0-pure.cl
index d56a3004b..8aaff8389 100644
--- a/OpenCL/m13100_a0-pure.cl
+++ b/OpenCL/m13100_a0-pure.cl
@@ -24,6 +24,7 @@ typedef struct krb5tgs
   u32 checksum[4];
   u32 edata2[5120];
   u32 edata2_len;
+  u32 format;
 
 } krb5tgs_t;
 
diff --git a/OpenCL/m13100_a1-optimized.cl b/OpenCL/m13100_a1-optimized.cl
index 749f12952..26c8e8111 100644
--- a/OpenCL/m13100_a1-optimized.cl
+++ b/OpenCL/m13100_a1-optimized.cl
@@ -23,6 +23,7 @@ typedef struct krb5tgs
   u32 checksum[4];
   u32 edata2[5120];
   u32 edata2_len;
+  u32 format;
 
 } krb5tgs_t;
 
diff --git a/OpenCL/m13100_a1-pure.cl b/OpenCL/m13100_a1-pure.cl
index ebdb14864..1799a64ee 100644
--- a/OpenCL/m13100_a1-pure.cl
+++ b/OpenCL/m13100_a1-pure.cl
@@ -22,6 +22,7 @@ typedef struct krb5tgs
   u32 checksum[4];
   u32 edata2[5120];
   u32 edata2_len;
+  u32 format;
 
 } krb5tgs_t;
 
diff --git a/OpenCL/m13100_a3-optimized.cl b/OpenCL/m13100_a3-optimized.cl
index c692199b6..2d2a47efc 100644
--- a/OpenCL/m13100_a3-optimized.cl
+++ b/OpenCL/m13100_a3-optimized.cl
@@ -23,6 +23,7 @@ typedef struct krb5tgs
   u32 checksum[4];
   u32 edata2[5120];
   u32 edata2_len;
+  u32 format;
 
 } krb5tgs_t;
 
diff --git a/OpenCL/m13100_a3-pure.cl b/OpenCL/m13100_a3-pure.cl
index 7db244812..166997b52 100644
--- a/OpenCL/m13100_a3-pure.cl
+++ b/OpenCL/m13100_a3-pure.cl
@@ -22,6 +22,7 @@ typedef struct krb5tgs
   u32 checksum[4];
   u32 edata2[5120];
   u32 edata2_len;
+  u32 format;
 
 } krb5tgs_t;
 
diff --git a/src/modules/module_13100.c b/src/modules/module_13100.c
index 8806d37ec..84edb28e9 100644
--- a/src/modules/module_13100.c
+++ b/src/modules/module_13100.c
@@ -47,7 +47,6 @@ typedef struct krb5tgs
   u32 checksum[4];
   u32 edata2[5120];
   u32 edata2_len;
-
   u32 format;
 
 } krb5tgs_t;

From 395d19513db2f4c2add067df892780a7b1121690 Mon Sep 17 00:00:00 2001
From: Gabriele Gristina <matrix@users.noreply.github.com>
Date: Sat, 26 Feb 2022 21:19:52 +0100
Subject: [PATCH 3/5] fix sample formats

---
 src/modules/module_13100.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/modules/module_13100.c b/src/modules/module_13100.c
index 84edb28e9..2a220ebaf 100644
--- a/src/modules/module_13100.c
+++ b/src/modules/module_13100.c
@@ -124,11 +124,11 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
   /**
    * hc
-   * format 1: $krb5tgs$23$*user*realm*spn*$checksum$edata2
+   * format 1: $krb5tgs$23$*user$realm$spn*$checksum$edata2
    * format 2: $krb5tgs$23$checksum$edata2
    *
    * jtr
-   * format 3: $krb5tgs$spn$checksum$edata2
+   * format 3: $krb5tgs$spn:checksum$edata2
    */
 
   if (line_len < 9) return (PARSER_SALT_LENGTH);

From 39912575b2894b58b80192baf1e123914abda579 Mon Sep 17 00:00:00 2001
From: Gabriele Gristina <matrix@users.noreply.github.com>
Date: Sun, 27 Feb 2022 12:12:22 +0100
Subject: [PATCH 4/5] fix style

---
 src/modules/module_13100.c | 81 +++++++++++++++++++++++---------------
 1 file changed, 50 insertions(+), 31 deletions(-)

diff --git a/src/modules/module_13100.c b/src/modules/module_13100.c
index 2a220ebaf..15adfbe4e 100644
--- a/src/modules/module_13100.c
+++ b/src/modules/module_13100.c
@@ -131,14 +131,17 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
    * format 3: $krb5tgs$spn:checksum$edata2
    */
 
-  if (line_len < 9) return (PARSER_SALT_LENGTH);
+  if (line_len < (int) strlen (SIGNATURE_KRB5TGS)) return (PARSER_SALT_LENGTH);
 
-  if (line_buf[9] == '2' && line_buf[10] == '3' && line_buf[11] == '$')
+  memset (krb5tgs, 0, sizeof (krb5tgs_t));
+
+  token.token_cnt = 4;
+
+  if (line_buf[token.len[0]] == '2' && line_buf[token.len[0] + 1] == '3' && line_buf[token.len[0] + 2] == '$')
   {
-    if (line_buf[12] == '*')
+    if (line_buf[token.len[0] + 3] == '*')
     {
       char *account_info_start = (char *) line_buf + 12; // we want the * char included
-
       char *account_info_stop  = strchr ((const char *) account_info_start + 1, '*');
 
       if (account_info_stop == NULL) return (PARSER_SEPARATOR_UNMATCHED);
@@ -148,7 +151,9 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
       const int account_info_len = account_info_stop - account_info_start;
 
-      token.token_cnt  = 5;
+      token.token_cnt++;
+
+      // etype
 
       token.sep[1]     = '$';
       token.len_min[1] = 2;
@@ -156,24 +161,32 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
       token.attr[1]    = TOKEN_ATTR_VERIFY_LENGTH
                        | TOKEN_ATTR_VERIFY_DIGIT;
 
+      // user$realm$spn
+
       token.len[2]     = account_info_len;
       token.attr[2]    = TOKEN_ATTR_FIXED_LENGTH;
 
+      // checksum
+
       token.sep[3]     = '$';
       token.len_min[3] = 32;
       token.len_max[3] = 32;
       token.attr[3]    = TOKEN_ATTR_VERIFY_LENGTH
                        | TOKEN_ATTR_VERIFY_HEX;
 
+      // edata2
+
       token.sep[4]     = '$';
       token.len_min[4] = 64;
       token.len_max[4] = 40960;
       token.attr[4]    = TOKEN_ATTR_VERIFY_LENGTH
                        | TOKEN_ATTR_VERIFY_HEX;
+
+      krb5tgs->format = 1;
     }
     else
     {
-      token.token_cnt  = 4;
+      // etype
 
       token.sep[1]     = '$';
       token.len_min[1] = 2;
@@ -181,82 +194,88 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
       token.attr[1]    = TOKEN_ATTR_VERIFY_LENGTH
                        | TOKEN_ATTR_VERIFY_DIGIT;
 
+      // checksum
+
       token.sep[2]     = '$';
       token.len_min[2] = 32;
       token.len_max[2] = 32;
       token.attr[2]    = TOKEN_ATTR_VERIFY_LENGTH
                        | TOKEN_ATTR_VERIFY_HEX;
 
+      // edata2
+
       token.sep[3]     = '$';
       token.len_min[3] = 64;
       token.len_max[3] = 40960;
       token.attr[3]    = TOKEN_ATTR_VERIFY_LENGTH
                        | TOKEN_ATTR_VERIFY_HEX;
+
+      krb5tgs->format = 2;
     }
   }
   else
   {
-    token.token_cnt  = 4;
+    // spn
 
     token.sep[1]     = ':';
     token.len_min[1] = 0;
     token.len_max[1] = 2048;
     token.attr[1]    = TOKEN_ATTR_VERIFY_LENGTH;
 
+    // checksum
+
     token.sep[2]     = '$';
     token.len_min[2] = 32;
     token.len_max[2] = 32;
     token.attr[2]    = TOKEN_ATTR_VERIFY_LENGTH
                      | TOKEN_ATTR_VERIFY_HEX;
 
+    // edata2
+
     token.sep[3]     = '$';
     token.len_min[3] = 64;
     token.len_max[3] = 40960;
     token.attr[3]    = TOKEN_ATTR_VERIFY_LENGTH
                      | TOKEN_ATTR_VERIFY_HEX;
+
+    krb5tgs->format = 3;
   }
 
   const int rc_tokenizer = input_tokenizer ((const u8 *) line_buf, line_len, &token);
 
   if (rc_tokenizer != PARSER_OK) return (rc_tokenizer);
 
-  const u8 *checksum_pos;
-  const u8 *data_pos;
+  u8 *checksum_pos = NULL;
+  u8 *data_pos = NULL;
 
-  int data_len;
+  int data_len = 0;
 
-  if (line_buf[9] == '2' && line_buf[10] == '3' && line_buf[11] == '$')
+  if (krb5tgs->format == 1)
   {
-    if (line_buf[12] == '*')
-    {
-      checksum_pos = token.buf[3];
+    checksum_pos = (u8 *) token.buf[3];
 
-      data_pos = token.buf[4];
-      data_len = token.len[4];
+    data_pos = (u8 *) token.buf[4];
+    data_len = token.len[4];
 
-      memcpy (krb5tgs->account_info, token.buf[2], token.len[2]);
-      krb5tgs->format = 1;
-    }
-    else
-    {
-      checksum_pos = token.buf[2];
+    memcpy (krb5tgs->account_info, token.buf[2], token.len[2]);
+  }
+  else if (krb5tgs->format == 2)
+  {
+    checksum_pos = (u8 *) token.buf[2];
 
-      data_pos = token.buf[3];
-      data_len = token.len[3];
+    data_pos = (u8 *) token.buf[3];
+    data_len = token.len[3];
 
-      krb5tgs->account_info[0] = 0;
-      krb5tgs->format = 2;
-    }
+    krb5tgs->account_info[0] = 0;
   }
-  else
+  else if (krb5tgs->format == 3)
   {
-    checksum_pos = token.buf[2];
+    checksum_pos = (u8 *) token.buf[2];
 
-    data_pos = token.buf[3];
+    data_pos = (u8 *) token.buf[3];
     data_len = token.len[3];
 
     memcpy (krb5tgs->account_info, token.buf[1], token.len[1]);
-    krb5tgs->format = 3;
   }
 
   krb5tgs->checksum[0] = hex_to_u32 (checksum_pos +  0);

From eb30a1c820108fd306cb7e5edb8ba659a7a46b64 Mon Sep 17 00:00:00 2001
From: Gabriele Gristina <matrix@users.noreply.github.com>
Date: Sun, 27 Feb 2022 14:26:34 +0100
Subject: [PATCH 5/5] fix Cygwin build warnings

---
 src/modules/module_13100.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/src/modules/module_13100.c b/src/modules/module_13100.c
index 15adfbe4e..9bb177dfb 100644
--- a/src/modules/module_13100.c
+++ b/src/modules/module_13100.c
@@ -245,39 +245,41 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
   if (rc_tokenizer != PARSER_OK) return (rc_tokenizer);
 
-  u8 *checksum_pos = NULL;
-  u8 *data_pos = NULL;
+  const u8 *checksum_pos = NULL;
+  const u8 *data_pos = NULL;
 
   int data_len = 0;
 
   if (krb5tgs->format == 1)
   {
-    checksum_pos = (u8 *) token.buf[3];
+    checksum_pos = token.buf[3];
 
-    data_pos = (u8 *) token.buf[4];
+    data_pos = token.buf[4];
     data_len = token.len[4];
 
     memcpy (krb5tgs->account_info, token.buf[2], token.len[2]);
   }
   else if (krb5tgs->format == 2)
   {
-    checksum_pos = (u8 *) token.buf[2];
+    checksum_pos = token.buf[2];
 
-    data_pos = (u8 *) token.buf[3];
+    data_pos = token.buf[3];
     data_len = token.len[3];
 
     krb5tgs->account_info[0] = 0;
   }
   else if (krb5tgs->format == 3)
   {
-    checksum_pos = (u8 *) token.buf[2];
+    checksum_pos = token.buf[2];
 
-    data_pos = (u8 *) token.buf[3];
+    data_pos = token.buf[3];
     data_len = token.len[3];
 
     memcpy (krb5tgs->account_info, token.buf[1], token.len[1]);
   }
 
+  if (checksum_pos == NULL || data_pos == NULL) return (PARSER_SALT_VALUE);
+
   krb5tgs->checksum[0] = hex_to_u32 (checksum_pos +  0);
   krb5tgs->checksum[1] = hex_to_u32 (checksum_pos +  8);
   krb5tgs->checksum[2] = hex_to_u32 (checksum_pos + 16);