Hardened-PHP and variable filtering extensions...

php.internals

Stefan Esser

21 years ago
Hello, recently there was a discussion on this list about variable filtering within PHP. Because of this discussion I have put a preview of Hardened-PHP 0.3.0 online at hardened-php.net. (This preview does not contain all new features but the variable filtering relevant ones. It adds the following new ini directives: Filtering Directives -------------------- # Global Policy for Request Variables # allow - all not explicitly forbidden contents are allowed # deny - all not explicitly allowed contents are forbidden hphp.request.policy = deny | allow # Global Filter for Request Variables hphp.request.filter = deny|allow /regexpattern/i # Variable Specific Filter hphp.request.varfilter = varname deny|allow /regexpattern/i (The same directives exist variable type specific: hphp.cookie.policy, hphp.post.policy, hphp.get.policy, ...) Limiting Directives ------------------- hphp.XXX.max_vars hphp.XXX.max_name_length hphp.XXX.max_totalname_length hphp.XXX.max_value_length hphp.XXX.max_array_depth hphp.XXX.max_array_index_length where XXX is request/get/post/cookie Fileupload Directives --------------------- hphp.upload.max_uploads - maximum number of file uploads per request hphp.upload.disallow_elf_files - disallow uploaded ELF files hphp.upload.verification_script - call this script to verify uploaded files Additionally the log system was improved Logging Directives ------------------ hphp.log.syslog = loglevels that should be logged through syslog (S_MEMORY is always logged through syslog) hphp.log.syslog.facility = syslog facility hphp.log.syslog.priority = syslog priority hphp.log.sapi = loglevels that should be logged through sapi error log (f.e. apache error log) hphp.log.script = loglevels thath should be logged through the logscript hphp.log.script.name = script for logging (1st param f.e. S_MISC 2nd param: message) loglevel meaning ----------------- S_MEMORY Log memory errors, like carnary violations S_VARS Log dropped variables S_INCLUDE Log malicious includes S_FILES Log malicious fileuploads S_SQL Log failed MySQL queries (f.e. someone trying to SQL inject) S_MISC Log other attacks (f.e. format string attacks) PS.1: You see that all filtering directives do drop the variables and do NOT try to remove malicious content. Repairing malicious input is considered bad practise. PS.2: Anyone interested in suggesting a new name for Hardened-PHP? Obviously the PHP Group does consider Hardened-PHP as violator of the PHP license and demands/wants a name change. PS.3: Yes some of these feature are similiar in mod_security (with the exception that in Hardened-PHP they actually work) Stefan Esser

Andi Gutmans

21 years ago
At 06:43 PM 2/14/2005 +0100, Stefan Esser wrote:
>Hello, > >recently there was a discussion on this list about variable filtering >within PHP. Because of this discussion I have put a preview of >Hardened-PHP 0.3.0 online at hardened-php.net. (This preview does not >contain all new features but the variable filtering relevant ones. > >It adds the following new ini directives: > >Filtering Directives >-------------------- > ># Global Policy for Request Variables ># allow - all not explicitly forbidden contents are allowed ># deny - all not explicitly allowed contents are forbidden > >hphp.request.policy = deny | allow > ># Global Filter for Request Variables > >hphp.request.filter = deny|allow /regexpattern/i > ># Variable Specific Filter > >hphp.request.varfilter = varname deny|allow /regexpattern/i > >(The same directives exist variable type specific: >hphp.cookie.policy, hphp.post.policy, hphp.get.policy, ...) > >Limiting Directives >------------------- >hphp.XXX.max_vars >hphp.XXX.max_name_length >hphp.XXX.max_totalname_length >hphp.XXX.max_value_length >hphp.XXX.max_array_depth >hphp.XXX.max_array_index_length > >where XXX is request/get/post/cookie > >Fileupload Directives >--------------------- >hphp.upload.max_uploads - maximum number of file uploads per request >hphp.upload.disallow_elf_files - disallow uploaded ELF files >hphp.upload.verification_script - call this script to verify uploaded files > >Additionally the log system was improved >Logging Directives >------------------ >hphp.log.syslog = loglevels that should be logged through syslog (S_MEMORY >is always logged through syslog) >hphp.log.syslog.facility = syslog facility >hphp.log.syslog.priority = syslog priority >hphp.log.sapi = loglevels that should be logged through sapi error log >(f.e. apache error log) >hphp.log.script = loglevels thath should be logged through the logscript >hphp.log.script.name = script for logging (1st param f.e. S_MISC 2nd >param: message) > >loglevel meaning >----------------- >S_MEMORY Log memory errors, like carnary violations >S_VARS Log dropped variables >S_INCLUDE Log malicious includes >S_FILES Log malicious fileuploads >S_SQL Log failed MySQL queries (f.e. someone trying to SQL inject) >S_MISC Log other attacks (f.e. format string attacks) > > >PS.1: You see that all filtering directives do drop the variables and do >NOT try to remove malicious content. Repairing malicious input is >considered bad practise.
Once we have input filtering in PHP, it might be interesting for you to extend that work in your project but I understand you want to provide something ASAP for your user base. Probably some of the things you'd do wouldn't be suitable for the mainstream PHP user base.
>PS.2: Anyone interested in suggesting a new name for Hardened-PHP? >Obviously the PHP Group does consider Hardened-PHP as violator of the PHP >license and demands/wants a name change.
How about Hardened Security for PHP? I guess that's a bit lame though :)
>PS.3: Yes some of these feature are similiar in mod_security (with the >exception that in Hardened-PHP they actually work)
:) Andi