Bug #71088 [Asn->Nab]: Session gets corrupted using custom session handler, unicode chars + 2 pg_conn

From: Date: Tue, 15 Dec 2015 00:32:07 +0000
Subject: Bug #71088 [Asn->Nab]: Session gets corrupted using custom session handler, unicode chars + 2 pg_conn
References: 1  Groups: php.bugs 
Request: Send a blank email to php-bugs+get-197888@lists.php.net to get a copy of this message 
Edit report at https://bugs.php.net/bug.php?id=71088&edit=1

 ID:                 71088
 Updated by:         yohgaki@php.net
 Reported by:        cdutary at grupocti dot com
 Summary:            Session gets corrupted using custom session handler,
                     unicode chars + 2 pg_conn
-Status:             Assigned
+Status:             Not a bug
 Type:               Bug
 Package:            Session related
 Operating System:   Windows 2008
 PHP Version:        7.0.0
 Assigned To:        yohgaki
 Block user comment: N
 Private report:     N

 New Comment:

Some kind of BYTEA escape/unescape issue.


Previous Comments:
------------------------------------------------------------------------
[2015-12-15 00:30:57] yohgaki@php.net

@cdutary 

I briefly checked PostgreSQL 8.4 and 9.x libpq code. PostgreSQL 8.4's PQunescapeBytea() does
not have support new escape method, but it seems 9.x code has older escape support.

I'm not sure why you get errors. Since I'm a pgsql module maintainer, I may investigate
what's wrong. Please open new pgsql module bug report, if you think your problem is some kind
of bug.

I'll close this bug.

------------------------------------------------------------------------
[2015-12-14 22:56:39] cdutary at grupocti dot com

Well, the seccond connection is made to a older version of postgres, session management is made on
the same version (9.4.4) both client and server so I guess this is the one that should matter.
My guess is that PHP, in order to be compatible with the seccond conection is using old
"techniques" against the new server as well.
I was expecting for php to handle both connections separately but I guess that is just not possible.


FIRST SERVER (session storage): PostgreSQL 9.4.4 on x86_64-unknown-linux-gnu, compiled by gcc (GCC)
4.4.7 20120313 (Red Hat 4.4.7-11), 64-bit

SECCOND SERVER: PostgreSQL 8.4.20 on x86_64-redhat-linux-gnu, compiled by GCC gcc (GCC) 4.4.7
20120313 (Red Hat 4.4.7-11), 64-bit

CLIENT(php): PostgreSQL(libpq) Version 9.4.4

------------------------------------------------------------------------
[2015-12-14 22:08:20] yohgaki@php.net

I don't get suspicious error.

--- modified test codes ----
ob_start();
session_start();
isset($_SESSION['aaa']) ? : 'Setting value' . $_SESSION['aaa'] =
'áéíóú'; //added unicode chars to our session data.
$_SESSION['cnt']++;
var_dump($_SESSION);
$pg_conn = pg_connect("host=localhost port=5432 dbname=yohgaki user=yohgaki");
------------------------------


1st access
------------------------------
Notice: Undefined index: cnt in /home/yohgaki/workspace/ext/git/oss/php.net/php-src/t3.php on line
156
array(2) { ["aaa"]=> string(10) "áéíóú" ["cnt"]=>
int(1) } 
-------------------------------

2nd access
-------------------------------
array(2) { ["aaa"]=> string(10) "áéíóú" ["cnt"]=>
int(2) } 
-------------------------------

It seems you are having problem with BYTEA escaping. What is your PostgreSQL version, both client
library(libpq) and server? Does client library (libpq) and server version match?

Check phpinfo() output for client library version.
Do "SELECT version()" for server version.

BYTEA escaping has been changed for better performance. It seems your environment has version
mismatch problem. If client library and server version matches, it should work.

------------------------------------------------------------------------
[2015-12-14 18:41:12] cdutary at grupocti dot com

I took your code and added the last 2 ingredients to make PHP fail and it did:

    ob_start();
    session_start();
    echo isset($_SESSION['aaa']) ? : 'Setting value' .
$_SESSION['aaa'] = 'áéíóú'; //added unicode chars to our session
data.
    var_dump($_SESSION['cnt'] ++);
    $pg_conn = pg_connect("host=´host2 port=5432 dbname=database2 user=user2
password=pass2"); //added a seccond pg_conn which somehow makes session unreadable


The output is:

PHP Warning:  session_start(): Failed to decode session object. 
Session has been destroyed in sesions.php on line 179
PHP Notice:  Undefined index: cnt in sesions.php on line 183


For now the workaround I found is to wrap up the session info in base64() before saving it into
php_session and unwrap it at read. This works with both session save handlers, your's and mine.


The original problem still remains and I can't find a reason for it yet.

------------------------------------------------------------------------
[2015-12-14 10:48:53] yohgaki@php.net

I just wrote an example save handler for PostgreSQL.

https://gist.github.com/yohgaki/a7b130bc93b2f9467ccc

Try this one and see if you have problems.

------------------------------------------------------------------------


The remainder of the comments for this report are too long. To view
the rest of the comments, please view the bug report online at

    https://bugs.php.net/bug.php?id=71088


--
Edit this bug report at https://bugs.php.net/bug.php?id=71088&edit=1

Thread (10 messages)

« previous php.bugs (#197888) next »