Bug 1071344

Summary:

PHP segfault's when you try and allocate an SplFixedArray with size >= 9999

Product:

Red Hat Enterprise Linux 6

Reporter:

Coty Sutherland <csutherl>

Component:

php

Assignee:

Remi Collet <rcollet>

Status:

CLOSED ERRATA

QA Contact:

Petr Šplíchal <psplicha>

Severity:

medium

Docs Contact:

Priority:

medium

Version:

6.5

CC:

csutherl, dkutalek, jorton, m.slowe, ohudlick, p.frost, psplicha, rcollet

Target Milestone:

Keywords:

Patch, Upstream

Target Release:

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Hardware:

x86_64

OS:

Linux

Whiteboard:

Fixed In Version:

Doc Type:

Bug Fix

Doc Text:

Story Points:

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Clone Of:

Environment:

Last Closed:

2016-05-10 21:37:48 UTC

Type:

Bug

Regression:

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Mount Type:

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Documentation:

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CRM:

Verified Versions:

Category:

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oVirt Team:

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RHEL 7.3 requirements from Atomic Host:

Cloudforms Team:

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Target Upstream Version:

Embargoed:

Bug Depends On:

Bug Blocks:

1075802, 1172231

Attachments:

Description	Flags
PHP script to reproduce behavior.	none

Description Coty Sutherland 2014-02-28 14:41:03 UTC

Description of problem:
When trying to fill an SplFixedArray object of length >= 9999 you get a segfault.

Version-Release number of selected component (if applicable):
6.5

How reproducible:
Every time when running with a PHP version < 5.3.8.

Steps to Reproduce:
1. Execute attached script.
2.
3.

Actual results:
With LENGTH < 9999: works fine.
With LENGTH >= 9999: Either a segfault or a 'zend_mm_heap_corrupted' error depending on whether the inner array is a regular array or a fixed array.
Output:
Array
 *RECURSION*Array
 ....
 *RECURSION*Array
(
Segmentation fault (core dumped)

Expected results:
Array
(
    [0] => test
    [1] => test2
)
.... // repeated about 9998 times

Additional info:
This seems to occur with PHP versions less than 5.3.8. I attached a bug report from years ago that was for this problem, but was closed because the problem disappeared in later versions. I was unable to find where it was fixed though.

Comment 1 Coty Sutherland 2014-02-28 14:42:10 UTC

Created attachment 869093 [details]
PHP script to reproduce behavior.

Comment 3 Remi Collet 2014-03-21 14:15:34 UTC

I think this is related to upstream bug 54609.

Upstream fix:
http://git.php.net/?p=php-src.git;a=commit;h=0afd4bd18bef55d8bce4d0fe854a65781477029a

This is related to the garbage collector.

With the provided reproducer, and a regular array

  $ php -d zend.enable_gc=1 /tmp/foo.php
  Array
   *RECURSION*Array
   ...
   *RECURSION*Array
  (
  Segmentation fault (core dumped)

With gc disabled => no segfault

  $ php -d zend.enable_gc=0 /tmp/foo.php
  ...
  Array
  (
      [0] => test
      [1] => test2
  )

With the provided reproducer, and a fixed array

  $ php -d zend.enable_gc=1 /tmp/foo.php 
  Segmentation fault (core dumped)

With gc disabled => no segfault

  $ php -d zend.enable_gc=0 /tmp/foo.php
  ...

         [8] => 
      [9] => 
  )

So can you please with test "zend.enable_gc=0" to confirm this.

Does the customer would be able to test a scratch build with this fix applied ?

Comment 4 Coty Sutherland 2014-03-24 14:22:40 UTC

Hi Remi,

That works for me in my environment. I will pass it on the customer and verify it works for them and also check to see if they can test a build with the fix applied.



Thanks!

Comment 5 Coty Sutherland 2014-03-25 13:20:30 UTC

> So can you please with test "zend.enable_gc=0" to confirm this.

"Yes -- disabling GC appears to make the segfault go away."

> Does the customer would be able to test a scratch build with this fix applied ?

They are willing to test a build if we get them one.

Comment 18 errata-xmlrpc 2016-05-10 21:37:48 UTC

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-0842.html