Provided by: libdbix-safe-perl_1.2.5-2_all 
NAME
DBIx::Safe - Safer access to your database through a DBI database handle
VERSION
This documents version 1.2.5 of the DBIx::Safe module
SYNOPSIS
use DBIx::Safe;
$dbh = DBI->connect($dbn, $user, $pass, {AutoCommit => 0});
my $safedbh = DBIx::Safe->new({ dbh => $dbh });
$safedbh->allow_command('SELECT INSERT UPDATE');
$safedbh->allow_regex(qr{LOCK TABLE \w+ IN EXCLUSIVE MODE});
$safedbh->deny_regex(qr{LOCK TABLE pg_});
$safedbh->allow_attribute('PrintError RaiseError');
DESCRIPTION
The purpose of this module is to give controlled, limited access to an application, rather than simply
passing it a raw database handle through DBI. DBIx::Safe acts as a wrapper to the database, by only
allowing through the commands you tell it to. It filters all things related to the database handle -
methods and attributes.
The typical usage is for your application to create a database handle via a normal DBI call to new(),
then pass that to DBIx::Safe->new(), which will return you a DBIx::Safe object. After specifying exactly
what is and what is not allowed, you can pass the object to the untrusted application. The object will
act very similar to a DBI database handle, and in most cases can be used interchangeably.
By default, nothing is allowed to run at all. There are many things you can control. You can specify
which SQL commands are allowed, by indicating the first word in the SQL statement (e.g. 'SELECT'). You
can specify which database methods are allowed to run (e.g. 'ping'). You can specify a regular expression
that allows matching SQL statements to run (e.g. 'qr{SET TIMEZONE}'). You can specify a regular
expression that is NOT allowed to run (e.g. qr(UPDATE xxx}). Finally, you can indicate which database
attributes are allowed to be read and changed (e.g. 'PrintError'). For all of the above, there are
matching methods to remove them as well.
Deciding what statements to allow
Anytime a statement is sent to the server via the DBIx::Safe database handle, it is first examined to see
if it is allowed to run or not. There are three major checks that occur when a statement is sent. First,
the initial word of the statement, known as the command, is extracted. Next, the entire statement is
checked against the list of denied regular expressions. Next, the command is checked against the list of
allowed commands. If there is no match, the statement is checked against the list of allowed regular
expressions.
Each DBD may implement additional or slightly different checks. For example, if using Postgres, no semi-
colons are allowed unless the command is one of SELECT, INSERT, UPDATE, or DELETE, to prevent multiple
commands from running. (The four listed commands can be checked in another way for multiple commands, so
they are allowed to have semicolons).
Deciding what attributes to allow
Database handle attributes are controlled by a single list of allowed keys. If the key is allowed, the
underlying database handle value is returned or changed (or both). Note that the attribute "AutoCommit"
is never allowed to be changed.
Methods
new()
Creates a new DBIx::Safe object. Requires a mandatory "dbh" argument containing an active database
handle. Optional arguments are "allow_command", "allow_regex", "deny_regex", and "allow_attribute".
allow_command()
Specifies which commands are allowed to be used. Can be a whitespace-separated list of words in a string,
or an arrayref of such strings. Returns the current list of allowed commands. Duplicate commands will
throw an error.
unallow_command()
Same as allow_command, but will remove words from the list.
allow_regex()
Specifies regular expressions which are allowed to run. Argument must be a regular expression, or an
arrayref of regular expressions. Returns the current list.
unallow_regex()
Same as allow_regex, but will remove regexes from the list.
deny_regex()
Specifies regular expressions which are NOT allowed to run. Arguments and return the same as
allow_regex().
undeny regex()
Same as deny_regex, but will remove regexes from the list.
allow_attribute()
Specifies database handle attributes that are allowed to be changed. By default, nothing can be read.
Argument is a whitespace-separated list of words in a string, or an arrayref of such strings. Returns the
current list.
unallow_attribute()
Same as allow_attributes, but removes attributes from the list.
Testing
DBIx::Safe has a very comprehensive test suite, so please use it! The only thing you should need is a
database connection, by setting the environment variables DBI_DSN and DBI_USER (and DBI_PASS if needed).
You can optionally run the module through Perl::Critic by setting the TEST_AUTHOR environment variable.
You will need to have the modules Perl::Critic and Test::Perl::Critic installed.
Please report any test failures to the author or bucardo-general@bucardo.org.
Supported Databases
Due to the difficulty of ensuring safe access to the database, each type of database must be specifically
written into DBIx::Safe. Current databases supported are: Postgres (DBD::Pg).
WEBSITE
The latest version and other information about DBIx::Safe can be found at: http://bucardo.org/dbix_safe/
DEVELOPMENT
The latest development version can be checked out by using git:
git clone http://bucardo.org/dbixsafe.git/
BUGS
Bugs should be reported to the author or bucardo-general@bucardo.org.
AUTHOR
Greg Sabino Mullane <greg@endpoint.com>
LICENSE AND COPYRIGHT
Copyright 2006-2007 Greg Sabino Mullane <greg@endpoint.com>. This software is free to use: see the LICENSE file for details.