# [Fwd: bug in odbc extension http://bugs.php.net/bug.php?id=37527]

- Thread: https://externals.io/message/32422
- Original archive: https://news-web.php.net/php.internals/32422
- Started by Alexandra S. on 2007-09-23T09:59:17+00:00
- Messages: 2
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## #32422 — Alexandra S. — 2007-09-23T09:59:17+00:00

URL: https://externals.io/message/32422#32422

Hi,

I am attaching here a patch for this bug.
Please review it.

-------- Original Message --------
Subject: 	bug in odbc extension http://bugs.php.net/bug.php?id=37527
Date: 	Tue, 18 Sep 2007 15:29:23 +0200
From: 	Alexandra S. <alexandra@zend.com>
To: 	internals@lists.php.net



Hi,


I have been trying to work on this bug. The problem here is in this 
scenario:

1. odbc connection is established.

2. odbc connection is closed.

3. trying to do a request (example: odbc_exec) to the database using the 
closed connection -> crash.



As far as I can understand from reading the odbc_exec() function, 
ZEND_FETCH_RESOURCE2 should return false,, so we do not advance to the 
SQLAllocStmt call that crashes.

I checked with php 5.2.4 on both Linux and Windows and 
ZEND_FETCH_RESOURCE2 does not return false.

The reason for it is in the odbc_close function -

for(i = 1; i < nument; i++){

      ptr = zend_list_find(i, &type);

      if(ptr && (type == le_result)){

          res = (odbc_result *)ptr;

          if(res->conn_ptr == conn){

              zend_list_delete(i);

          }

      }    
  }

Here only the  previous statements of this connection are deleted and 
not the connection itself.

In the odbc_close_all function all the statements are deleted, and then 
all the connections.



I suggest to add the deletion of the connection itself to the odbc_close 
function - so the ZEND_FETCH_RESOURCE2 check will actually work. The 
situation now is that check do not work and we try all the time to call 
SQL actions with no existent connections.



Example for possible solution:



for(i = 1; i < nument; i++){

      ptr = zend_list_find(i, &type);

      if(ptr && (type == le_result)){

          res = (odbc_result *)ptr;

          if(res->conn_ptr == conn){

              zend_list_delete(i);

          }

      }

      if(ptr && (type == (is_pconn?le_pconn:le_conn))){

          res = (odbc_result *)ptr;

          if(res == conn){

              zend_list_delete(i);

          }

      }

  }


Alexandra Shpindovsky

---

## #32442 — Dmitry Stogov — 2007-09-25T07:58:34+00:00

URL: https://externals.io/message/32422#32442 · In reply to: #32422

Hi Alexandra,

I'm not sure in tis patch.
It does the same as double calling to zend_list_delete(Z_LVAL_PP(pv_conn));
Also your fix may cause deletion of connection (le_conn) before deletion of
related results (le_result).
Is it allowed?

Thanks. Dmitry.

> -----Original Message-----
> From: Alexandra S. [mailto:alexandra@zend.com] 
> Sent: Sunday, September 23, 2007 1:59 PM
> To: internals@lists.php.net
> Subject: [PHP-DEV] [Fwd: bug in odbc extension 
> http://bugs.php.net/bug.php?id=37527]
> 
> 
> Hi,
> 
> I am attaching here a patch for this bug.
> Please review it.
> 
> -------- Original Message --------
> Subject: 	bug in odbc extension 
> http://bugs.php.net/bug.php?id=37527
> Date: 	Tue, 18 Sep 2007 15:29:23 +0200
> From: 	Alexandra S. <alexandra@zend.com>
> To: 	internals@lists.php.net
> 
> 
> 
> Hi,
> 
> 
> I have been trying to work on this bug. The problem here is in this 
> scenario:
> 
> 1. odbc connection is established.
> 
> 2. odbc connection is closed.
> 
> 3. trying to do a request (example: odbc_exec) to the 
> database using the 
> closed connection -> crash.
> 
> 
> 
> As far as I can understand from reading the odbc_exec() function, 
> ZEND_FETCH_RESOURCE2 should return false,, so we do not 
> advance to the 
> SQLAllocStmt call that crashes.
> 
> I checked with php 5.2.4 on both Linux and Windows and 
> ZEND_FETCH_RESOURCE2 does not return false.
> 
> The reason for it is in the odbc_close function -
> 
> for(i = 1; i < nument; i++){
> 
>       ptr = zend_list_find(i, &type);
> 
>       if(ptr && (type == le_result)){
> 
>           res = (odbc_result *)ptr;
> 
>           if(res->conn_ptr == conn){
> 
>               zend_list_delete(i);
> 
>           }
> 
>       }    
>   }
> 
> Here only the  previous statements of this connection are deleted and 
> not the connection itself.
> 
> In the odbc_close_all function all the statements are 
> deleted, and then 
> all the connections.
> 
> 
> 
> I suggest to add the deletion of the connection itself to the 
> odbc_close 
> function - so the ZEND_FETCH_RESOURCE2 check will actually work. The 
> situation now is that check do not work and we try all the 
> time to call 
> SQL actions with no existent connections.
> 
> 
> 
> Example for possible solution:
> 
> 
> 
> for(i = 1; i < nument; i++){
> 
>       ptr = zend_list_find(i, &type);
> 
>       if(ptr && (type == le_result)){
> 
>           res = (odbc_result *)ptr;
> 
>           if(res->conn_ptr == conn){
> 
>               zend_list_delete(i);
> 
>           }
> 
>       }
> 
>       if(ptr && (type == (is_pconn?le_pconn:le_conn))){
> 
>           res = (odbc_result *)ptr;
> 
>           if(res == conn){
> 
>               zend_list_delete(i);
> 
>           }
> 
>       }
> 
>   }
> 
> 
> Alexandra Shpindovsky