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diff --git a/fml/doc/en/tutorial/internals/restriction.sgml b/fml/doc/en/tutorial/internals/restriction.sgml new file mode 100644 index 00000000..60731434 --- /dev/null +++ b/fml/doc/en/tutorial/internals/restriction.sgml @@ -0,0 +1,202 @@ +<!-- + $FML: restriction.sgml,v 1.9 2005/06/25 15:11:35 fukachan Exp $ +--> + + +<chapter id="restriction"> + <title> + Restrict input data + </title> + +<para> +&fml8; checks the input by regular expression FML::Restriction class +provides. +</para> + + +<sect1 id="restriction.overview"> + <title> + Overview: checks of input data + </title> + +<sect2> + <title> + Restriction for article posting + </title> + +<para> +Restrictions for article are ambiguous or too restrictive. In fact +FML::Restriction class does not provide restriction rules for article +posting. +</para> + +<para> +Instead FML::Filter filter system checks each line of content. +</para> + +</sect2> + + +<sect2> + <title> + Restrictions for command mail + </title> + +<para> +FML::Process::Command class parses each line of the command mail and +checks the input by regular expressions FML::Restriction::Command +provides. If the check is passed, &fml8; calls +FML::Command::{User,Admin}::COMMAND at the next step. +</para> + +</sect2> + + +<sect2> + <title> + CGI + </title> + +<para> +CGI programs can receive the input from HTTP via only safe_param_XXX() +method. +</para> + +<para> +It is expected that +safe_param_*() +and +try_cgi_*() +returns the safe value. +</para> + +<para> +These safe_param_XXX() functions checks the input by regular +expressions FML::Restriction::CGI provides (FML::Restriction::CGI +inherits FML::Restriction::Base). +</para> + +</sect2> + + +<sect2> + <title> + makefml / fml + </title> + +<para> +CUI runs on the shell. +It means he/she who runs CUI has priviledge to log in the mailing list +server. +So it does not check the input. +</para> + +<para> +Each module checks the input independetly in that case +though no checks by FML::Restriction at the entrance. +For example, "adduser" module checks whether the input address +is valid or not even in the case of CUI. +These restrictions are dependent command specific modules. +</para> + +</sect2> + +</sect1> + + +<sect1 id="restriction.class"> + <title> + FML::Restriction class + </title> + +<para> +ACLs for the input data and commands are found at FML::Restriction +class. +</para> + +<para> +For example, CGI modules use FML::Restriction::CGI class to check +if the input data matches the proper regular expression. +</para> + +<para> +Though FML::Restriction inherits FML::Restriction::Base class, +fundamentally each module should use FML::Restriction as object +composition. For example, use in the following way: +<screen> +use FML::Restriction::CGI; +$safe = new FML::Restriction::CGI; +my $allowed_regexp = $safe->param_regexp(); + +if ($value =~ /^$allowed_regexp{$key}$) { ... ok, do something ... ;} +</screen> +</para> + +</sect1> + + +<sect1 id="restrictioncgi.input.data"> + <title> + How CGI restricts the input + </title> + +<para> +CGI checks the input data by using FML::Restriction::CGI class. +</para> + +<para> +The input should be restricted by FML::Restriction class. +We should not use param() method provided by perl's CGI class. +Instead use safe_param_xxx() method always to get value. +</para> + +<para> +The following use may be allowed +<screen> +for my $dirty_buf (param()) { + ... check ... +} +</screen> +but we should not use raw param() call. +<screen> +param($dirtty_buf) +</screen> +Instead, use safe_param_key(). +<screen> +for my $key (param()) { + ... check ... + + if (key eq $key) { + value = safe_param_key() + } +} +</screen> +</para> + +</sect1> + + +<sect1> + <title> + Discussion: FML::Restriction is too restrictive ? + </title> + +<para> +FML::Restriction class allows a subset of RFC defined expression. +</para> + +<para> +RRC definition is too large. +It is too difficult to implement it ;-) +We restrict the expression a little. +</para> + +<para> +FML::Restriction::Command may be more granular but more granular +version is not implemented. +</para> + +</sect1> + + +</chapter> |