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Bug #39498 ext/mcrypt/mcrypt.c hardcoded to use /dev/random
Submitted: 2006-11-13 15:48 UTC Modified: 2006-11-13 17:50 UTC
From: mark at exonetric dot com Assigned:
Status: Not a bug Package: Performance problem
PHP Version: 4.4.4 OS: Linux 2.6/Debian Etch
Private report: No CVE-ID: None
 [2006-11-13 15:48 UTC] mark at exonetric dot com
mcrypt.c appears to be written to use /dev/random for entropy in all cases. As good entropy is a limited resource when obtained from /dev/random, code that makes frequent calls to mcrypt routines that require entropy can block waiting for entropy unexpectedly. 

 PHP_FUNCTION(mcrypt_create_iv) should be modified to permit configuration of /dev/random or /dev/urandom at least at compile time if not at run time.

Reproduce code:
any code that calls mcrypt routines frequently

Expected result:
if called frequently enough, will block waiting for entropy.


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 [2006-11-13 15:58 UTC]
You can use MCRYPT_DEV_URANDOM and get the data for /dev/urandom.
 [2006-11-13 17:50 UTC] mark at exonetric dot com
right, i can see now there is some odd zend_parameter stuff that fiddles with the source variable directly. That's very non-intuitive and will teach me to read docs I suppose.
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