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Bug #72828 superfluous NULL check in php_strtr_array
Submitted: 2016-08-13 11:45 UTC Modified: 2016-08-13 14:45 UTC
From: cmb@php.net Assigned: cmb (profile)
Status: Not a bug Package: Strings related
PHP Version: 5.6Git-2016-08-13 (Git) OS: *
Private report: No CVE-ID: None
 [2016-08-13 11:45 UTC] cmb@php.net
Description:
------------
In php_strtr_array_prepare_repls() `patterns` and `*allocs` are
allocated on the heap, but it is not checked whether that might
have failed, what can lead to OOB writes.

This may not be a problem with the Zend MM, but can be with other
memory managers.

If that also affects PHP 7 (where strtr() had be reimplemented),
has to be checked.


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 [2016-08-13 11:45 UTC] cmb@php.net
-Assigned To: +Assigned To: cmb
 [2016-08-13 12:05 UTC] nikic@php.net
Unless the allocations explicitly use the system allocator (i.e. do not use emalloc and variants), do NOT introduce NULL checks.
 [2016-08-13 13:39 UTC] cmb@php.net
-Summary: php_strtr_array_prepare_repls does not check allocation results +Summary: superfluous NULL check in php_strtr_array
 [2016-08-13 13:39 UTC] cmb@php.net
That has been further clarified on the internals mailing list[1].
So I'm changing the bug wrt. to the superfluous NULL check in
php_strtr_array()[2].

[1] <http://news.php.net/php.internals/95114>
[2] <https://github.com/php/php-src/blob/php-5.6.24/ext/standard/string.c#L3134-L3136>
 [2016-08-13 14:45 UTC] cmb@php.net
-Status: Assigned +Status: Not a bug
 [2016-08-13 14:45 UTC] cmb@php.net
I've found that this issue indeed only affects PHP 5. After
reconsideration I think the NULL check is harmless – at least it
is not a bug.
 
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