<html><head><style type="text/css"><!-- DIV {margin:0px;} --></style></head><body><div style="font-family:times new roman,new york,times,serif;font-size:12pt">That's understandable. I can pass on the word to some of the PHP
implementations, at least, and check on the PECL C extension for PHP. It has already been resolved (or
marked for resolution at next minor version) for a few months in
anything I'm personally involved in. PHP must have anything over 20 reasonably commonly available OpenID/OAuth libs including C extensions.<br><br>> The only fair comparison here is when the two inputs are equal.<br>>
Lengthening the time of computation when the inputs are different is<br>>
the goal of this fix.<br><br>True, that was what I benchmarked last November or so when I was researching this topic and ported the suggested function to PHP. It's implicit in benchmarking to compare like with like. As I recall, the only concern at the time with the replacement function was that it leaked length information (somewhat leaky for variable length passwords or phrases rather than the documented fixed length of something derived from HMAC). No idea if anyone else in PHP has been talking about timing attacks of this nature though - any new data from the Blackhat conf can only help raise awareness and get over developers' initial disbelief - "internet jitter" remains a compelling argument with those I've mentioned timing attacks to.<br><br>Paddy<br><div> </div><span style="color: rgb(0, 0, 191);"><font style="font-family: times new roman,new york,times,serif;" size="3"><span style="font-weight: bold;">Pádraic
Brady<br><br></span></font><span style="font-style: italic;"><font style="font-family: times new roman,new york,times,serif;" size="3"><a rel="nofollow" target="_blank" href="http://blog.astrumfutura.com/">http://blog.astrumfutura.com</a><br><a rel="nofollow" target="_blank" href="http://www.survivethedeepend.com/">http://www.survivethedeepend.com</a><br><u><font color="#0000ff"><a rel="nofollow" target="_blank" href="http://framework.zend.com">Zend Framework Community Review Team</a></font></u><br></font></span></span><div><br></div><div style="font-family: times new roman,new york,times,serif; font-size: 12pt;"><br><div style="font-family: tahoma,new york,times,serif; font-size: 8pt;"><font face="Tahoma" size="2"><hr size="1"><b><span style="font-weight: bold;">From:</span></b> Nate Lawson <nate@rootlabs.com><br><b><span style="font-weight: bold;">To:</span></b> Breno de Medeiros <breno@google.com><br><b><span style="font-weight:
bold;">Cc:</span></b> Pádraic Brady <padraic.brady@yahoo.com>; Andrew Arnott <andrewarnott@gmail.com>; openid-security <openid-security@lists.openid.net><br><b><span style="font-weight: bold;">Sent:</span></b> Fri, July 16, 2010 6:45:37 PM<br><b><span style="font-weight: bold;">Subject:</span></b> Re: [security] Widespread Timing Vulnerabilities in OpenID implementations<br></font><br>
Breno de Medeiros wrote:<br>> On Fri, Jul 16, 2010 at 08:02, Pádraic Brady <<a ymailto="mailto:padraic.brady@yahoo.com" href="mailto:padraic.brady@yahoo.com">padraic.brady@yahoo.com</a>> wrote:<br>>> I can only speak for PHP, but the function is also multiples slower than a<br>>> native comparison from when I was implementing it last year. Not all that<br>>> surprising given PHP is also built on C (to the point it practically copies<br>>> functions) so it should resolve similarly.<br>> <br>> The only fair comparison here is when the two inputs are equal.<br>> Lengthening the time of computation when the inputs are different is<br>> the goal of this fix.<br><br>Yes, that's what I was checking on.<br><br>>> Just on implementations - have you notified these directly? Not all of them<br>>> may be paying attention to this list since it's not necessarily<br>>> implementation specific.<br><br>No,
there are too many. We've also notified all OAuth, various web<br>frameworks, and others not yet public. There are at least 30 known<br>affected libraries and up to double that unknown. We can't review<br>everything.<br><br>-- <br>Nate Lawson<br>Root Labs :: <a target="_blank" href="http://www.rootlabs.com">www.rootlabs.com</a><br>+1 (510) 595-9505 / (415) 305-5638 mobile<br>Solving embedded security, kernel and crypto challenges<br><br></div></div>
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