php.net |  support |  documentation |  report a bug |  advanced search |  search howto |  statistics |  random bug |  login
Bug #55395 php soap extension passes unsafe zvals to user functions, corrupting memory
Submitted: 2011-08-11 03:12 UTC Modified: 2020-11-22 04:22 UTC
Votes:1
Avg. Score:3.0 ± 0.0
Reproduced:1 of 1 (100.0%)
Same Version:1 (100.0%)
Same OS:1 (100.0%)
From: askalski at gmail dot com Assigned: cmb (profile)
Status: No Feedback Package: SOAP related
PHP Version: 5.4SVN-2011-08-11 (snap) OS: linux
Private report: No CVE-ID: None
Have you experienced this issue?
Rate the importance of this bug to you:

 [2011-08-11 03:12 UTC] askalski at gmail dot com
Description:
------------
The PHP SOAP extension passes unsafe zvals as arguments to user functions (for example, __doRequest.)  If that user function saves a reference to those zvals, it leads to memory corruption, generally resulting in a segmentation fault.

Two example problems from ext/soap/soap.c.  The whole SOAP extension needs to be audited for this:

(1) Allocating a zval on the stack, then passing a pointer to that zval into a user function:
  zval param0;
  params[0] = &param0;
  call_user_function(..., params ...);

(2) Failing to duplicate string buffers:

  // 'buf' is freed while references to its zval potentially still exist
  xmlDocDumpMemory(request, (xmlChar**)&buf, &buf_size);
  ZVAL_STRINGL(params[0], buf, buf_size, 0); // needs to be ", 1);"
  call_user_function(..., params ...);
  xmlFree(buf);

  static int do_request(..., char *location, ...) {
      // 'location' is malloc memory that may be freed before the zval
      ZVAL_STRING(params[1], location, 0); // needs to be ", 1);"
      call_user_function(..., params ...);


Test script:
---------------
<?php
class CorruptSoap extends SoapClient {
        function __doRequest($request, $location, $action, $version, $one_way) {
                global $params;
                $params = array(
                        'request' => $request,
                        'location' => $location,
                        'action' => $action,
                        'version' => $version,
                        'one_way' => $one_way);
                debug_zval_dump($params); // Before
                return "";
        }
}
$x = new CorruptSoap(NULL, array('location' => 'http://location/', 'uri' => 'http://uri/'));
$x->Test();
debug_zval_dump($params); // After
?>


Expected result:
----------------
The before/after debug_zval_dump output should look the same, with slightly different (but valid) reference counts.


Actual result:
--------------
Before the stack gets smashed:

    array(5) refcount(1){
      ["request"]=>
      string(375) "<?xml version="1.0" encoding="UTF-8"?>
    <SOAP-ENV:Envelope xmlns:SOAP-ENV="http://schemas.xmlsoap.org/soap/envelope/" xmlns:ns1="http://uri/" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:SOAP-ENC="http://schemas.xmlsoap.org/soap/encoding/" SOAP-ENV:encodingStyle="http://schemas.xmlsoap.org/soap/encoding/"><SOAP-ENV:Body><ns1:Test/></SOAP-ENV:Body></SOAP-ENV:Envelope>
    " refcount(5)
      ["location"]=>
      string(16) "http://location/" refcount(5)
      ["action"]=>
      string(16) "http://uri/#Test" refcount(5)
      ["version"]=>
      long(1) refcount(5)
      ["one_way"]=>
      long(0) refcount(5)
    }

After the stack has been smashed:

    array(5) refcount(2){
      ["request"]=>
      NULL refcount(0)
      ["location"]=>
      NULL refcount(0)
      ["action"]=>
      NULL refcount(0)
      ["version"]=>
      NULL refcount(10153504)
      ["one_way"]=>
      NULL refcount(0)
    }


Patches

Add a Patch

Pull Requests

Add a Pull Request

History

AllCommentsChangesGit/SVN commitsRelated reports
 [2011-08-12 01:19 UTC] felipe@php.net
-Status: Open +Status: Assigned -Assigned To: +Assigned To: dmitry
 [2017-10-24 07:57 UTC] kalle@php.net
-Status: Assigned +Status: Open -Assigned To: dmitry +Assigned To:
 [2020-11-11 14:00 UTC] cmb@php.net
-Status: Open +Status: Feedback -Assigned To: +Assigned To: cmb
 [2020-11-11 14:00 UTC] cmb@php.net
This appears to be obsolete at least as of PHP 7.0.0, since
ZVAL_STRINGL() now copies anyway.
 [2020-11-22 04:22 UTC] php-bugs at lists dot php dot net
No feedback was provided. The bug is being suspended because
we assume that you are no longer experiencing the problem.
If this is not the case and you are able to provide the
information that was requested earlier, please do so and
change the status of the bug back to "Re-Opened". Thank you.
 
PHP Copyright © 2001-2021 The PHP Group
All rights reserved.
Last updated: Mon May 10 19:01:24 2021 UTC