Mod_auth_mysql Django Authentication

I needed a way to get mod_auth mysql to work with django password scheme so that I can have a single sign-on between apache and django. Unfortunately, Django uses a salted password scheme (hashtype$salt$Password) while mod_auth_mysql expects unsalted hashes. To take advantage of the salting advantages, it's better to update mod_auth_mysql to understand django's password scheme.
Well since blogger doesn't allow me to upload a patch file, here it goes
Patch for mod-auth-mysql-4.3.9
----

--- mod_auth_mysql.c-pristine   2010-05-04 17:07:43.000000000 +0400
+++ mod_auth_mysql.c    2010-05-04 17:08:01.000000000 +0400
@@ -103,6 +103,8 @@
 #endif
 #define SHA1SUM_ENCRYPTION_FLAG                1<<6
 
+#define DJANGO_ENCRYPTION_FLAG         1<<8
+
 static int check_no_encryption(const char *passwd, char *enc_passwd)
 {
        return (!strcmp(passwd, enc_passwd));
@@ -226,6 +228,86 @@
        return (!strcmp(sha1_hex_hash(passwd), enc_passwd));
 }
 
+static int check_django_encryption(const char *passwd, char *enc_passwd)
+{
+       char *delim = "$";
+        char *hash_type, *cp, *hash, *salt, *salted_passwd, *free_cp;
+       int ret;
+
+        // Since strtok alters the string it is parsing,
+       // we should always copy the string to a temporary buffer
+       cp = strdup (enc_passwd);
+
+       // strdup()  function  returns a pointer to the duplicated string, or
+       // NULL if insufficient memory was available
+       if (cp == NULL){
+               //TODO: Use the proper log for these errors. Not syslog
+               syslog(LOG_DEBUG, "Module_Auth_MySQL: Couldn't allocate memory for %s.\nExiting\n", cp);
+               return 0;
+       }
+       free_cp = cp;
+
+
+       //split the hash_type out
+       hash_type = strtok(cp, delim);
+       if (hash_type == NULL){
+               syslog(LOG_DEBUG, "Module_Auth_MySQL: Couldn't find %s in %s.\nExiting\n",delim, cp);
+               free(free_cp);
+               return 0;
+       }
+
+       //split the salt out
+       salt = strtok(NULL, delim);
+       if (salt == NULL){
+               syslog(LOG_DEBUG, "Module_Auth_MySQL: Couldn't find %s in %s.\nExiting\n",delim, cp);
+               free(free_cp);
+               return 0;
+       }
+
+       //split the salt out
+       hash = strtok(NULL, delim);
+       if (hash == NULL){
+               syslog(LOG_DEBUG, "Module_Auth_MySQL: Couldn't find %s in %s.\nExiting\n",delim, cp);
+               free(free_cp);
+               return 0;
+       }
+
+#ifdef DEBUG
+       syslog(LOG_DEBUG, "MAMDEBUG: DJANGO called: passwd:%s enc_password:%s", passwd, enc_passwd);
+       syslog(LOG_DEBUG, "MAMDEBUG: Hash method: %s\n", hash_type);
+       syslog(LOG_DEBUG, "MAMDEBUG: Salt: %s\n", salt);
+       syslog(LOG_DEBUG, "MAMDEBUG: Hash: %s\n", hash);
+#endif
+
+       // Concat salt and password.
+       salted_passwd = malloc(strlen(salt)+strlen(passwd)+1);
+       if (salted_passwd == NULL){
+               syslog(LOG_DEBUG, "Module_Auth_MySQL: Couldn't allocate memory for %s.\nExiting\n", salted_passwd);
+               free(free_cp);
+               return 0;
+       }
+       strcpy(salted_passwd, salt);
+       strcat(salted_passwd, passwd);
+       
+       if( !strcmp(hash_type, "sha1") ) {
+               ret = (!strcmp(sha1_hex_hash(salted_passwd), hash));
+       }
+       else if( !strcmp(hash_type, "md5") ) {
+               ret = (!strcmp(md5_hex_hash(salted_passwd), hash));
+       }
+       else {
+               syslog(LOG_DEBUG, "Module_Auth_MySQL: Uknown salt type %s.", hash_type);        
+               ret = 0;
+       }
+
+       //Free the strdup resource and the malloc resource
+       free(free_cp);
+       free(salted_passwd);
+
+        return ret;
+}
+
+
 
 static int check_mysql_encryption(const char *passwd, char *enc_passwd)
 {
@@ -254,6 +336,7 @@
        { "PHP_MD5",            check_PHP_MD5_encryption,               PHP_MD5_ENCRYPTION_FLAG },
        { "SHA1Sum",    check_SHA1Sum_encryption, SHA1SUM_ENCRYPTION_FLAG},
        /* add additional encryption types below */
+       { "Django",     check_django_encryption, DJANGO_ENCRYPTION_FLAG},
        { NULL,                 NULL,                                   0 }
 };

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A dpatch is also available for debian users. Read more about dpatch here. Remember to update your 00list :)