From 7371cbebe70418fd139a25e2929afb4483e93777 Mon Sep 17 00:00:00 2001
From: Gabriele Gristina <matrix@users.noreply.github.com>
Date: Sun, 4 Jul 2021 20:14:25 +0200
Subject: [PATCH] add min/max data length limits to MetaMask Wallet

---
 OpenCL/inc_cipher_aes-gcm.cl |   2 +-
 OpenCL/m26600-pure.cl        | 214 +----------------------------------
 src/modules/module_26600.c   |  57 ++++++----
 tools/test_modules/m26600.pm |  14 ++-
 4 files changed, 47 insertions(+), 240 deletions(-)

diff --git a/OpenCL/inc_cipher_aes-gcm.cl b/OpenCL/inc_cipher_aes-gcm.cl
index fb560558c..b8d9bd1f9 100644
--- a/OpenCL/inc_cipher_aes-gcm.cl
+++ b/OpenCL/inc_cipher_aes-gcm.cl
@@ -219,7 +219,7 @@ DECLSPEC void AES_GCM_gctr (const u32 *key, const u32 *iv, const u32 *in, int in
   iv_buf[2] = iv[2];
   iv_buf[3] = iv[3];
 
-  const int n = in_len / 16;
+  const u32 n = in_len / 16;
 
   for (u32 i = 0; i < n; i++)
   {
diff --git a/OpenCL/m26600-pure.cl b/OpenCL/m26600-pure.cl
index fca3bcfcf..eaa22a061 100644
--- a/OpenCL/m26600-pure.cl
+++ b/OpenCL/m26600-pure.cl
@@ -34,7 +34,7 @@ typedef struct pbkdf2_sha256_aes_gcm
   u32 salt_buf[64];
   u32 iv_buf[4];
   u32 iv_len;
-  u32 ct_buf[192];
+  u32 ct_buf[196];
   u32 ct_len;
 
 } pbkdf2_sha256_aes_gcm_t;
@@ -349,34 +349,6 @@ KERNEL_FQ void m26600_comp (KERN_ATTR_TMPS_ESALT (pbkdf2_sha256_tmp_t, pbkdf2_sh
 
   // ct
 
-  /*
-  u32 enc[14] = { 0 };
-
-  enc[ 0] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 0];
-  enc[ 1] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 1];
-  enc[ 2] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 2];
-  enc[ 3] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 3];
-  enc[ 4] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 4];
-  enc[ 5] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 5];
-  enc[ 6] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 6];
-  enc[ 7] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 7];
-  enc[ 8] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 8];
-  enc[ 9] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 9];
-  enc[10] = esalt_bufs[DIGESTS_OFFSET].ct_buf[10];
-  enc[11] = esalt_bufs[DIGESTS_OFFSET].ct_buf[11];
-  enc[12] = esalt_bufs[DIGESTS_OFFSET].ct_buf[12];
-  enc[13] = esalt_bufs[DIGESTS_OFFSET].ct_buf[13];
-
-  u32 enc_len = esalt_bufs[DIGESTS_OFFSET].ct_len;
-  */
-
-  /*
-  // decrypt buffer is not usefull here, skip
-  u32 dec[14] = { 0 };
-
-  AES_GCM_GCTR (key, J0, enc, enc_len, dec, s_te0, s_te1, s_te2, s_te3, s_te4);
-  */
-
   u32 T[4] = { 0 };
   u32 S[4] = { 0 };
 
@@ -384,8 +356,6 @@ KERNEL_FQ void m26600_comp (KERN_ATTR_TMPS_ESALT (pbkdf2_sha256_tmp_t, pbkdf2_sh
   u32 aad_buf[4] = { 0 };
   u32 aad_len = 0;
 
-  //AES_GCM_GHASH (subKey, aad_buf, aad_len, enc, enc_len, S);
-
   AES_GCM_GHASH_GLOBAL (subKey, aad_buf, aad_len, esalt_bufs[DIGESTS_OFFSET].ct_buf, esalt_bufs[DIGESTS_OFFSET].ct_len, S);
 
   AES_GCM_GCTR (key, J0, S, S_len, T, s_te0, s_te1, s_te2, s_te3, s_te4);
@@ -403,185 +373,3 @@ KERNEL_FQ void m26600_comp (KERN_ATTR_TMPS_ESALT (pbkdf2_sha256_tmp_t, pbkdf2_sh
   #include COMPARE_M
   #endif
 }
-
-/*
-Optimized GCM: No real speed benefit. For documentation purpose
-
-KERNEL_FQ void m26600_comp (KERN_ATTR_TMPS_ESALT (pbkdf2_sha256_tmp_t, pbkdf2_sha256_aes_gcm_t))
-{
-  const u64 gid = get_global_id (0);
-  const u64 lid = get_local_id (0);
-  const u64 lsz = get_local_size (0);
-
-  #ifdef REAL_SHM
-
-  LOCAL_VK u32 s_te0[256];
-  LOCAL_VK u32 s_te1[256];
-  LOCAL_VK u32 s_te2[256];
-  LOCAL_VK u32 s_te3[256];
-  LOCAL_VK u32 s_te4[256];
-
-  for (u32 i = lid; i < 256; i += lsz)
-  {
-    s_te0[i] = te0[i];
-    s_te1[i] = te1[i];
-    s_te2[i] = te2[i];
-    s_te3[i] = te3[i];
-    s_te4[i] = te4[i];
-  }
-
-  SYNC_THREADS ();
-
-  #else
-
-  CONSTANT_AS u32a *s_te0 = te0;
-  CONSTANT_AS u32a *s_te1 = te1;
-  CONSTANT_AS u32a *s_te2 = te2;
-  CONSTANT_AS u32a *s_te3 = te3;
-  CONSTANT_AS u32a *s_te4 = te4;
-
-  #endif
-
-  if (gid >= gid_max) return;
-
-  // keys
-
-  u32 ukey[8];
-
-  ukey[0] = tmps[gid].out[0];
-  ukey[1] = tmps[gid].out[1];
-  ukey[2] = tmps[gid].out[2];
-  ukey[3] = tmps[gid].out[3];
-  ukey[4] = tmps[gid].out[4];
-  ukey[5] = tmps[gid].out[5];
-  ukey[6] = tmps[gid].out[6];
-  ukey[7] = tmps[gid].out[7];
-
-  u32 key[60] = { 0 };
-
-  u32 subKey[4] = { 0 };
-
-  AES256_set_encrypt_key (key, ukey, s_te0, s_te1, s_te2, s_te3);
-
-  AES256_encrypt (key, subKey, subKey, s_te0, s_te1, s_te2, s_te3, s_te4);
-
-  // iv
-
-  const u32 iv[4] = {
-    esalt_bufs[DIGESTS_OFFSET].iv_buf[0],
-    esalt_bufs[DIGESTS_OFFSET].iv_buf[1],
-    esalt_bufs[DIGESTS_OFFSET].iv_buf[2],
-    esalt_bufs[DIGESTS_OFFSET].iv_buf[3]
-  };
-
-  u32 J0[4] = {
-    iv[0],
-    iv[1],
-    iv[2],
-    0x00000001
-  };
-
-  // ct
-
-  u32 enc[14] = { 0 };
-
-  enc[ 0] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 0];
-  enc[ 1] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 1];
-  enc[ 2] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 2];
-  enc[ 3] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 3];
-  enc[ 4] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 4];
-  enc[ 5] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 5];
-  enc[ 6] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 6];
-  enc[ 7] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 7];
-  enc[ 8] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 8];
-  enc[ 9] = esalt_bufs[DIGESTS_OFFSET].ct_buf[ 9];
-  enc[10] = esalt_bufs[DIGESTS_OFFSET].ct_buf[10];
-  enc[11] = esalt_bufs[DIGESTS_OFFSET].ct_buf[11];
-  enc[12] = esalt_bufs[DIGESTS_OFFSET].ct_buf[12];
-  enc[13] = esalt_bufs[DIGESTS_OFFSET].ct_buf[13];
-
-  u32 enc_len = esalt_bufs[DIGESTS_OFFSET].ct_len;
-
-  u32 S[4] = { 0 };
-
-  u32 t[4] = { 0 };
-
-  S[0] ^= enc[0];
-  S[1] ^= enc[1];
-  S[2] ^= enc[2];
-  S[3] ^= enc[3];
-
-  AES_GCM_gf_mult (S, subKey, t);
-
-  S[0] = t[0] ^ enc[4];
-  S[1] = t[1] ^ enc[5];
-  S[2] = t[2] ^ enc[6];
-  S[3] = t[3] ^ enc[7];
-
-  AES_GCM_gf_mult (S, subKey, t);
-
-  S[0] = t[0] ^ enc[8];
-  S[1] = t[1] ^ enc[9];
-  S[2] = t[2] ^ enc[10];
-  S[3] = t[3] ^ enc[11];
-
-  AES_GCM_gf_mult (S, subKey, t);
-
-  S[0] = t[0];
-  S[1] = t[1];
-  S[2] = t[2];
-  S[3] = t[3];
-
-  t[0] = enc[12];
-  t[1] = enc[13];
-  t[2] = 0;
-  t[3] = 0;
-
-  S[0] ^= t[0];
-  S[1] ^= t[1];
-  S[2] ^= t[2];
-  S[3] ^= t[3];
-
-  AES_GCM_gf_mult (S, subKey, t);
-
-  S[0] = t[0];
-  S[1] = t[1];
-  S[2] = t[2];
-  S[3] = t[3];
-
-  u32 len_buf[4] = { 0 };
-
-  len_buf[0] = 0;
-  len_buf[3] = enc_len * 8;
-
-  S[0] ^= len_buf[0];
-  S[1] ^= len_buf[1];
-  S[2] ^= len_buf[2];
-  S[3] ^= len_buf[3];
-
-  AES_GCM_gf_mult (S, subKey, t);
-
-  S[0] = t[0];
-  S[1] = t[1];
-  S[2] = t[2];
-  S[3] = t[3];
-
-  J0[3] = 0x00000001;
-
-  u32 T[4] = { 0 };
-
-  AES256_encrypt (key, J0, T, s_te0, s_te1, s_te2, s_te3, s_te4);
-
-  const u32 r0 = T[0] ^ S[0];
-  const u32 r1 = T[1] ^ S[1];
-  const u32 r2 = T[2] ^ S[2];
-  const u32 r3 = T[3] ^ S[3];
-
-  #define il_pos 0
-
-  #ifdef KERNEL_STATIC
-  #include COMPARE_M
-  #endif
-}
-
-*/
diff --git a/src/modules/module_26600.c b/src/modules/module_26600.c
index 46bc0c2b9..ac271b515 100644
--- a/src/modules/module_26600.c
+++ b/src/modules/module_26600.c
@@ -57,7 +57,7 @@ typedef struct pbkdf2_sha256_aes_gcm
   u32 salt_buf[64];
   u32 iv_buf[4];
   u32 iv_len;
-  u32 ct_buf[192];
+  u32 ct_buf[196];
   u32 ct_len;
 
 } pbkdf2_sha256_aes_gcm_t;
@@ -113,6 +113,8 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
   pbkdf2_sha256_aes_gcm_t *metamask = (pbkdf2_sha256_aes_gcm_t *) esalt_buf;
 
+  #define CT_MAX_LEN_BASE64 ((768 * 8) / 6) + 3
+
   token_t token;
 
   token.token_cnt  = 4;
@@ -137,8 +139,8 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
                    | TOKEN_ATTR_VERIFY_BASE64A;
 
   token.sep[3]     = '$';
-  token.len_min[3] = 248;
-  token.len_max[3] = 248;
+  token.len_min[3] = 64;
+  token.len_max[3] = CT_MAX_LEN_BASE64;
   token.attr[3]    = TOKEN_ATTR_VERIFY_LENGTH
                    | TOKEN_ATTR_VERIFY_BASE64A;
 
@@ -146,7 +148,7 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
   if (rc_tokenizer != PARSER_OK) return (rc_tokenizer);
 
-  u8 tmp_buf[512] = { 0 };
+  u8 tmp_buf[CT_MAX_LEN_BASE64] = { 0 };
 
   size_t tmp_len = 0;
 
@@ -189,7 +191,7 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
   if (tmp_len != 16) return (PARSER_IV_LENGTH);
 
-  memcpy ((u8 *)metamask->iv_buf, tmp_buf, tmp_len);
+  memcpy ((u8 *) metamask->iv_buf, tmp_buf, tmp_len);
 
   metamask->iv_buf[0] = byte_swap_32 (metamask->iv_buf[0]);
   metamask->iv_buf[1] = byte_swap_32 (metamask->iv_buf[1]);
@@ -207,24 +209,27 @@ int module_hash_decode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
   tmp_len = base64_decode (base64_to_int, ct_pos, ct_len, tmp_buf);
 
-  if (tmp_len != 185) return (PARSER_CT_LENGTH);
+  if (tmp_len <= 16) return (PARSER_CT_LENGTH);
 
-  memcpy ((u8 *)metamask->ct_buf, tmp_buf, tmp_len - 16);
+  tmp_len -= 16;
 
-  for (u32 i = 0; i < 43; i++)
-  {
-    metamask->ct_buf[i] = byte_swap_32 (metamask->ct_buf[i]);
-  }
+  if (tmp_len < 30 || tmp_len > 768) return (PARSER_CT_LENGTH);
 
-  metamask->ct_len = tmp_len - 16;
+  memcpy ((u8 *) metamask->ct_buf, tmp_buf, tmp_len);
 
-  // tag
+  u32 j = tmp_len / 4;
+
+  if ((tmp_len % 4) > 0) j++;
 
-  u32 tag_buf[4];
+  for (u32 i = 0; i < j; i++) metamask->ct_buf[i] = byte_swap_32 (metamask->ct_buf[i]);
 
-  memset (tag_buf, 0, sizeof (tag_buf));
+  metamask->ct_len = tmp_len;
 
-  memcpy ((u8 *)tag_buf, tmp_buf+metamask->ct_len, 16);
+  // tag
+
+  u32 tag_buf[4] = { 0 };
+
+  memcpy ((u8 *) tag_buf, tmp_buf+metamask->ct_len, 16);
 
   digest[0] = byte_swap_32 (tag_buf[0]);
   digest[1] = byte_swap_32 (tag_buf[1]);
@@ -242,9 +247,9 @@ int module_hash_encode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
   // salt
 
-  #define SALT_LEN_BASE64 ((32 * 8) / 6) + 3
-  #define IV_LEN_BASE64   ((16 * 8) / 6) + 3
-  #define CT_LEN_BASE64   ((185 * 8) / 6) + 3
+  #define SALT_LEN_BASE64   ((32  * 8) / 6) + 3
+  #define IV_LEN_BASE64     ((16  * 8) / 6) + 3
+  #define CT_MAX_LEN_BASE64 ((768 * 8) / 6) + 3
 
   u8 salt_buf[SALT_LEN_BASE64] = { 0 };
 
@@ -259,15 +264,21 @@ int module_hash_encode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
   tmp_iv_buf[2] = byte_swap_32 (metamask->iv_buf[2]);
   tmp_iv_buf[3] = byte_swap_32 (metamask->iv_buf[3]);
 
-  u8 iv_buf[IV_LEN_BASE64] = { 0 };
+  u8 iv_buf[IV_LEN_BASE64+1] = { 0 };
 
   base64_encode (int_to_base64, (const u8 *) tmp_iv_buf, (const int) metamask->iv_len, iv_buf);
 
   // ct
 
-  u32 tmp_buf[47] = { 0 };
+  u32 ct_len = metamask->ct_len;
+
+  u32 j = ct_len / 4;
+
+  if ((ct_len % 4) > 0) j++;
+
+  u32 tmp_buf[196] = { 0 };
 
-  for (int i = 0; i < 43; i++) tmp_buf[i] = byte_swap_32 (metamask->ct_buf[i]);
+  for (u32 i = 0; i < j; i++) tmp_buf[i] = byte_swap_32 (metamask->ct_buf[i]);
 
   u32 tmp_tag[4] = { 0 };
 
@@ -281,7 +292,7 @@ int module_hash_encode (MAYBE_UNUSED const hashconfig_t *hashconfig, MAYBE_UNUSE
 
   memcpy (tmp_buf_str+metamask->ct_len, tmp_tag_str, 16);
 
-  u8 ct_buf[CT_LEN_BASE64] = { 0 };
+  u8 ct_buf[CT_MAX_LEN_BASE64] = { 0 };
 
   base64_encode (int_to_base64, (const u8 *) tmp_buf, (const int) metamask->ct_len+16, ct_buf);
 
diff --git a/tools/test_modules/m26600.pm b/tools/test_modules/m26600.pm
index 7b41ff2b7..3897bc670 100644
--- a/tools/test_modules/m26600.pm
+++ b/tools/test_modules/m26600.pm
@@ -21,6 +21,9 @@ sub module_generate_hash
   my $iv   = shift // random_hex_string (32);
   my $ct   = shift;
 
+  my $ct_min_len = 30;
+  my $ct_max_len = 768;
+
   my $kdf = Crypt::PBKDF2->new
   (
     hasher     => Crypt::PBKDF2->hasher_from_algorithm ('HMACSHA2', 256),
@@ -55,12 +58,12 @@ sub module_generate_hash
     }
     else
     {
-      $pt = "\xff" x 169;
+      $pt = "\xff" x ($ct_min_len + int(rand($ct_max_len - $ct_min_len)) + 1);
     }
   }
   else
   {
-    $pt = "\xff" x 169;
+    $pt = "\xff" x ($ct_min_len + int(rand($ct_max_len - $ct_min_len)) + 1);
   }
 
   my $aes = Crypt::AuthEnc::GCM->new ("AES", $key, $iv_bin);
@@ -100,7 +103,12 @@ sub module_verify_hash
 
   return unless length $salt_bin == 32;
   return unless length $iv_bin   == 16;
-  return unless length $ct_bin   == 185;
+
+  my $ct_len = length ($ct_bin);
+  my $ct_min_len = 30;
+  my $ct_max_len = 768;
+
+  return unless ($ct_len >= $ct_min_len && $ct_len <= $ct_max_len);
 
   my $word_packed = pack_if_HEX_notation ($word);