Re: Connecting remotely - multi tier

Cedar Cox <cedarc@visionforisrael.com> el día Thu, 2 Nov 2000 17:18:48 +0200 
(IST), escribió:

>You seem to have given this a lot of thought so let me ask a question.  
>How do I implement a user login system?  If the user knows their password
>(and don't they always?..), what's to stop them from finding and
>contacting the database directly, bypassing the middle tier?

because you setup the database (ie. pg_hba.conf) so that ONLY and only
the machine thas has the middle tier can connect to the database directly,
no other machine in the world can conect to the databse bypassing the
middle tier (even if the user know all passwords).

>  I haven't
>been able to find a solution to this problem.  Every time I try to think
>about it by brain goes into a recursive loop!  :o

this is what I've done:

I implemented a login system with php (using http authentication), 
so the machine running apache and php (the only machine with direct 
access to the db) connect with with the db with the username & password 
in behalf of the user.

this is my routine:

function sak_db_auth()
{ global $db_conf; global $PHP_AUTH_USER; global $PHP_AUTH_PW;

//  header("Cache-Control: no-cache");
//  header("Pragma: no-cache"); header("Expires: Sat, Jan 01 2000 01:01:01 GMT");
 function login_prompt() {   global $db_conf;   header("WWW-Authenticate: Basic realm=\"" . $db_conf["realm"] . "\"");
header("HTTP/1.0 401 Unauthorized");   echo "<meta HTTP-EQUIV=\"Refresh\" CONTENT=\"0; URL=" . 
 
$db_conf["url_on_cancel"] . "\">";   exit; }
 if (!isset($PHP_AUTH_USER)) {   login_prompt(); } else {   if($PHP_AUTH_USER && $PHP_AUTH_PW)   {     if
(!in_array($PHP_AUTH_USER,$db_conf["allowed_users"]))     {       return(false);     }
 
     $db_conf["user"] = $PHP_AUTH_USER;     $db_conf["password"] = $PHP_AUTH_PW;     $db_conf["str_conn"] = "dbname=" .
$db_conf["dbname"]. " user=" . 
 
$db_conf["user"] . " password=" . $db_conf["password"];
     $db = @pg_connect($db_conf["str_conn"]);
     if (!$db) {       $result = false;     } else {       pg_close($db);       $result = true;     }   } }
return($result);
}

in this way the users cannot connect directly to the db with crap 
like access, excel and so on ..

>On Wed, 1 Nov 2000, Sergio A. Kessler wrote:
>
>> "Adam Lang" <aalang@rutgersinsurance.com> el día Wed, 1 Nov 2000 09:52:35 
>> -0500, escribió:
>> 
>> [...]
>> >
>> >What are people's thoughts?
>> 
>> people's thoughts are that you really want to design a multi-thier
>> design (for example a 3 layer design), where
>> 
>>                                             /  client1 (browser)
>>  database  <--->   bussines rules           -  client2 (browser)
>>                   (ie. apache, php,...)     \  .....
>> 
>> 
>> if your client has direct access to the database, you design is broken...
>> 
>> sergio
>> 
>>