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HTML-FormHandler-0.40068
⭐ Starred 89 / HTML::FormHandler::Result
Security Advisories (1)
CVE-2022-4993 (2026-08-13)

HTML::FormHandler versions through 0.40068 for Perl allow attacker selected method dispatch and resource exhaustion because _apply_actions and add_error use error message text built from request data as a Locale::Maketext bracket notation template. add_error hands its first argument to the language handle as the Locale::Maketext message key, and the default handle's lexicon sets `_AUTO`, so a string that is not a lexicon entry is compiled as a bracket notation template instead of being looked up. In a bracket group the first token names a method called on the language handle and the remaining tokens are its arguments. Three kinds of text the library did not author reach that position. _apply_actions installs a `$SIG{__WARN__}` handler that stores the warning text in `$error_message`, and a captured warning survives a successful action, so a field carrying a numeric transform turns `Argument "[sprintf,%50000000d,0]" isn't numeric` into the template; a warning quotes the submitted value verbatim, so the group is well formed and dispatches. `$error_message ||= $tobj->validate($new_value)` takes a type constraint's own failure message, which renders the rejected value through a partial dumper in bracket and comma form (Devel::PartialDump when Moose can load it, Type::Tiny's own dumper always), so a field with `apply => [ Str ]` given a parameter sent more than once, which arrives as an array, gets `Reference ["a","b"] did not pass type constraint "Str"` as its template, from a request that carries no bracket character of its own. A coercion or transform exception reaches it the same way. Beyond those, a validator whose message contains the field value puts that value in the template directly, and add_error replaces the message list with the contents of an arrayref first argument (`@message = @{$message[0]} if ref $message[0] eq 'ARRAY'`), so a value arriving as an array fills the argument slots from the same request as well. A malformed group such as `[0]` makes the compile croak, and HTML::FormHandler::I18N::maketext and add_error each re-raise that as a die, so process() throws. A well formed group naming sprintf reaches CORE::sprintf with an attacker chosen field width. Any caller that applies a type constraint or a transform to an untrusted field, or whose validator passes an untrusted field value to add_error, can be made to throw an unhandled exception out of process(), or to allocate an arbitrary amount of memory in one request, and an application whose language handle subclass defines side effecting public methods makes those callable with attacker chosen arguments. The dumped type constraint message is bounded to the exception, because both dumpers quote non-numeric elements so the method slot is never an attacker chosen name. The built-in messages pass fixed templates with the value in an argument slot, where it stays inert, and the built-in field types attach explicit message callbacks, so neither is affected.

NAME

HTML::FormHandler::Result - form result object

VERSION

version 0.40068

SYNOPSIS

This is the Result object that maps to the Form.

my $result = $self->form->run( $params );
my $result2 = $self->form->run( $other_params );

my $value = $result->field('title')->value;
my $fif = $result->fif;
my $field_fid = $result->field('title')->fif;

DESCRIPTION

Although not experimental, the 'results' have not been exercised as much as the other parts of the code. If there is missing functionality or things that don't work, please ask or report bugs.

The original FormHandler 'process' method, when used with persistent forms, leaves behind state data for a particular execution of 'process'. This is not optimal or clean from an architectural point of view. The intention with the 'result' object is to separate dynamic data from static. The 'form' object is treated as a kind of result factory, which will spit out results and leave the form in a consistent state.

In the current state of implementation, the result object can be used to render a form:

$result->render;

However there are still open questions about how much of the form/field should be forwarded to the result. At this point, the number of forwarded methods is minimal. Mechanisms to make this more customizable are being considered.

Dynamic select lists are not supported yet. Static select lists (that are the same for every form execution) should work fine, but lists that are different depending on some field value will not.

Most of this object is implemented in HTML::FormHandler::Result::Role, because it is shared with HTML::FormHandler::Field::Result.

AUTHOR

FormHandler Contributors - see HTML::FormHandler

COPYRIGHT AND LICENSE

This software is copyright (c) 2017 by Gerda Shank.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.