PHP: rfc:crypt_function_salt

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====== PHP RFC: Change crypt() behavior w/o salt ======
  * Version: 1.0
  * Date: 2013-08-22
  * Author: Yasuo Ohgaki ( yohgaki@ohgaki.net )
  * Status: Accepted
  * First Published at: http://wiki.php.net/rfc/crypt_function_salt

===== Introduction =====

crypt() without "salt" parameter produces too weak password hash. However, many users are using crypt() without salt parameter.

===== Proposal =====

There are several options for this issue.

  - Make crypt() generates stronger salt and uses strong hash automatically.
  - Raise E_STRICT or E_NOTICE when salt is omitted.
  - Leave crypt() as it is now and warn users by document.

===== Backward Incompatible Changes =====

  * Option 1 may generate backward incompatible hash. 
  * Option 2 may break apps due to error.
  * Option 3 does not change crypt() and no issue. 

===== Proposed PHP Version(s) =====

master branch

===== Proposed Voting Choices =====

Option 1 to 3.

===== Patches and Tests =====

Patch for option 1 is posted to internals ML by Platonides <platonides@gmail.com>

<code>
diff --git a/ext/standard/crypt.c b/ext/standard/crypt.c
index 113a5bd..7731808 100644
--- a/ext/standard/crypt.c
+++ b/ext/standard/crypt.c
@@ -98,8 +98,6 @@
 #define PHP_STD_DES_CRYPT 1
 #endif

-#define PHP_CRYPT_RAND php_rand(TSRMLS_C)
-
 PHP_MINIT_FUNCTION(crypt) /* {{{ */
 {
        REGISTER_LONG_CONSTANT("CRYPT_SALT_LENGTH", PHP_MAX_SALT_LEN, CONST_CS | CONST_PERSISTENT);
@@ -134,17 +132,6 @@ PHP_MSHUTDOWN_FUNCTION(crypt) /* {{{ */
 }
 /* }}} */

-static unsigned char itoa64[] = "./0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
-
-static void php_to64(char *s, long v, int n) /* {{{ */
-{
-       while (--n >= 0) {
-               *s++ = itoa64[v&0x3f];
-               v >>= 6;
-       }
-}
-/* }}} */
-
 PHPAPI int php_crypt(const char *password, const int pass_len, const char *salt, int salt_len, char **result)
 {
        char *crypt_res;
@@ -278,11 +265,14 @@ PHP_FUNCTION(crypt)
        if (!*salt) {
 #if PHP_MD5_CRYPT
                strncpy(salt, "$1$", PHP_MAX_SALT_LEN);
-               php_to64(&salt[3], PHP_CRYPT_RAND, 4);
-               php_to64(&salt[7], PHP_CRYPT_RAND, 4);
+               if (php_password_make_salt(8, &salt[3] TSRMLS_CC) == FAILURE) {
+                       RETURN_FALSE;
+               }
                strncpy(&salt[11], "$", PHP_MAX_SALT_LEN - 11);
 #elif PHP_STD_DES_CRYPT
-               php_to64(&salt[0], PHP_CRYPT_RAND, 2);
+               if (php_password_make_salt(2, &salt[0] TSRMLS_CC) == FAILURE) {
+                       RETURN_FALSE;
+               }
                salt[2] = '\0';
 #endif
                salt_in_len = strlen(salt);
</code>

===== Vote =====

The vote started on 24.09.2013 and ended on 01.10.2013. 

<doodle title="Change crypt behavior when salt parameter is omitted." auth="yohgaki" voteType="single" closed="true">
   * Generate strong salt by default
   * Generate E_NOTICE error
   * Keep current behavior (Use weak hash)
</doodle>


===== References =====

  * http://jp2.php.net/crypt
  * https://bugs.php.net/bug.php?id=55036
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