Re: Common CGI Options" the "Check file" and "Rule" -> "Check local file"
Hugo Vazquez Carames <hvazquez <at> pentest.es>
2011-09-03 12:25:56 GMT
my "I/O cache" is enabled: I did it as soon I saw it
My concern is about the impact on checking for the existence of a file on
every request... that means that for every PHP request, there will be a
disk access...?? My system has been designed to serve a minimum of 10k
request/second serving php -actually it can support more than this-. I
have no logs, and I have all I can running from memory/cached, etc.
Having the "Check file" in my FastCGI handler, makes me think about
Cherokee doing a disk access in every request...Is that right? But not
having the "Check file" enabled, maybe would allow an attacker to pass
requests to FastCGI of non-existent files, forcing the FastCGI to do a lot
of disk access, and maybe, creating a denial of service condition...
So, summarizing: what could happen if i disable the "Check file" in my
FastCGI handler working with php-cgi?
And also, what could happen if I disable the "Rule" -> "Check local file"
in a "Extensions" rule -extensions: php,tpe-?
On Sat, 03 Sep 2011 14:00:44 +0200, Alvaro Lopez Ortega
<alvaro <at> octality.com> wrote:
> Hello Hugo,
> 2011/9/3 Hugo Vazquez Carames <hvazquez <at> pentest.es>
>> I'm wondering if in a high loaded server is better to have in "Handler"
>> "Common CGI Options" the "Check file" enabled or not,
> Well, that would have quite a big impact on what information are passed
> the *CGI. The option points the server whether it's executing the
> content of
> a file (CGI, a PHP file through FastCGI) or it's just passing the
> URL to a backend server (uWSGI, SCGI, FastCGI, etc) without even checking
> whether the file exists. Imagine a Django/RoR app, for instance. In that
> case you do not want the server to check any local file, simply because
> do not exist.
> and in "Rule" -> "Check local file" enabled or not... I would like to
>> uncheck both for performance reasons, but I'm not sure to if there's any
>> impact on security...
> I'm confused about this one. It depends on the rule. Most likely you want
> keep it enabled, but I could not tell you for sure without knowing a
> more about the specific case.
> Anyway, if you are worried about performance AND it's a production system
> you aren't developing on AND you can spend a few hundled Mb of RAM on it,
> I'd strongly recommend you to enable "I/O-cache". That will have a
> very positive impact on the overall server performance.
Hugo Vázquez Caramés
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