Merge pull request #181 from Sopsy/master

Add support for difficulty setting for php_crypt

config.inc.php

@@ -174,6 +174,12 @@ $CONF['smtp_client'] = '';
 // mysql_encrypt = useful for PAM integration
 // authlib = support for courier-authlib style passwords - also set $CONF['authlib_default_flavor']
 // dovecot:CRYPT-METHOD = use dovecotpw -s 'CRYPT-METHOD'. Example: dovecot:CRAM-MD5
+// php_crypt:CRYPT-METHOD:DIFFICULTY = use PHP built in crypt()-function. Example: php_crypt:SHA512:50000
+// - php_crypt CRYPT-METHOD: Supported values are DES, MD5, BLOWFISH, SHA256, SHA512
+// - php_crypt DIFFICULTY: Larger value is more secure, but uses more CPU and time for each login.
+// - php_crypt DIFFICULTY: Set this according to your CPU processing power.
+// - php_crypt DIFFICULTY: Supported values are BLOWFISH:4-31, SHA256:1000-999999999, SHA512:1000-999999999
+// - php_crypt DIFFICULTY: leave empty to use default values (BLOWFISH:10, SHA256:5000, SHA512:5000). Example: php_crypt:SHA512
 //     IMPORTANT:
 //     - don't use dovecot:* methods that include the username in the hash - you won't be able to login to PostfixAdmin in this case
 //     - you'll need at least dovecot 2.1 for salted passwords ('doveadm pw' 2.0.x doesn't support the '-t' option)

functions.inc.php

@@ -1067,14 +1067,18 @@ function _pacrypt_php_crypt($pw, $pw_db) {
         $salt = $pw_db;
     } else {
         $salt_method = 'SHA512'; // hopefully a reasonable default (better than MD5)
+        $hash_difficulty = '';
         // no pw provided. create new password hash
         if (strpos($CONF['encrypt'], ':') !== false) {
             // use specified hash method
             $split_method = explode(':', $CONF['encrypt']);
             $salt_method = $split_method[1];
+            if (count($split_method) >= 3) {
+                $hash_difficulty = $split_method[2];
+            }
         }
         // create appropriate salt for selected hash method
-        $salt = _php_crypt_generate_crypt_salt($salt_method);
+        $salt = _php_crypt_generate_crypt_salt($salt_method, $hash_difficulty);
     }
     // send it to PHPs crypt()
     $password = crypt($pw, $salt);
@@ -1085,7 +1089,7 @@ function _pacrypt_php_crypt($pw, $pw_db) {
  * @param string $hash_type must be one of: MD5, DES, BLOWFISH, SHA256 or SHA512  (default)
  * @return string
  */
-function _php_crypt_generate_crypt_salt($hash_type='SHA512') {
+function _php_crypt_generate_crypt_salt($hash_type='SHA512', $hash_difficulty=null) {
     // generate a salt (with magic matching chosen hash algorithm) for the PHP crypt() function
 
     // most commonly used alphabet
@@ -1106,7 +1110,14 @@ function _php_crypt_generate_crypt_salt($hash_type='SHA512') {
 
     case 'BLOWFISH':
         $length = 22;
-        $cost = 10;
+        if (empty($hash_difficulty)) {
+            $cost = 10;
+        } else {
+            $cost = (int)$hash_difficulty;
+            if ($cost < 4 || $cost > 31) {
+                die('invalid encrypt difficulty setting "' . $hash_difficulty . '" for ' . $hash_type . ', the valid range is 4-31');
+            }
+        }
         if (version_compare(PHP_VERSION, '5.3.7') >= 0) {
             $algorithm = '2y'; // bcrypt, with fixed unicode problem
         } else {
@@ -1118,14 +1129,36 @@ function _php_crypt_generate_crypt_salt($hash_type='SHA512') {
     case 'SHA256':
         $length = 16;
         $algorithm = '5';
+        if (empty($hash_difficulty)) {
+            $rounds = '';
+        } else {
+            $rounds = (int)$hash_difficulty;
+            if ($rounds < 1000 || $rounds > 999999999) {
+                die('invalid encrypt difficulty setting "' . $hash_difficulty . '" for ' . $hash_type . ', the valid range is 1000-999999999');
+            }
+        }
         $salt = _php_crypt_random_string($alphabet, $length);
-        return sprintf('$%s$%s', $algorithm, $salt);
+        if (!empty($rounds)) {
+            $rounds = sprintf('rounds=%d$', $rounds);
+        }
+        return sprintf('$%s$%s%s', $algorithm, $rounds, $salt);
 
     case 'SHA512':
         $length = 16;
         $algorithm = '6';
+        if (empty($hash_difficulty)) {
+            $rounds = '';
+        } else {
+            $rounds = (int)$hash_difficulty;
+            if ($rounds < 1000 || $rounds > 999999999) {
+                die('invalid encrypt difficulty setting "' . $hash_difficulty . '" for ' . $hash_type . ', the valid range is 1000-999999999');
+            }
+        }
         $salt = _php_crypt_random_string($alphabet, $length);
-        return sprintf('$%s$%s', $algorithm, $salt);
+        if (!empty($rounds)) {
+            $rounds = sprintf('rounds=%d$', $rounds);
+        }
+        return sprintf('$%s$%s%s', $algorithm, $rounds, $salt);
 
     default:
         die("unknown hash type: '$hash_type'");