WebAuth

(Perl extension for WebAuth)

SYNOPSIS

    use WebAuth;

    my $wa = WebAuth->new;
    eval {
        $key = $wa->random_key(WebAuth::WA_AES_128);
        ...
    };
    if ($@) {
        # handle exception
    }

WebAuth is a low-level Perl interface into the WebAuth C API. It mostly follows the C API but rearranges the calls into an object-oriented structure and changes the behavior of some methods to be more Perl-like.

Before calling any of the functions, obtain a new WebAuth object with WebAuth->new. All subsequent functions take that object as their first parameter, or should be called as methods on that object, and other returned objects will normally have that context as hidden data. This object represents the WebAuth context. If the WebAuth object goes out of scope, all other objects created from it, such as keys and keyrings, will also become invalid. The caller therefore must be careful to ensure that no references to other objects are kept around after the WebAuth object is destroyed.

All and methods functions have the potential to croak with a WebAuth::Exception object, so an eval block should be placed around calls to WebAuth functions if you intend to recover from errors. See WebAuth::Exception for more information.

In some cases, objects in other classes may be returned by methods. Those classes are documented in their own manual or POD pages.

EXPORT

Nothing is exported by default, but the following export tags are available:

const: Exports the WA_* constants. For a complete list, see CONSTANTS.

To import all constants, use:

    use WebAuth qw(:const);

Individual constants can be imported instead, of course.

CLASS METHODS

As described above, on any error not explicitly documented below, these methods will throw a WebAuth::Exception object.

new (): Create a new WebAuth context object and return it. Remember that all other objects created from this context, such as keys, keyrings, and tokens, will be destroyed when this context is destroyed, even though Perl isn't aware of this.

INSTANCE METHODS

As described above, on any error not explicitly documented below, these methods will throw a WebAuth::Exception object.

error_message (STATUS)

Returns an error message string corresponding to STATUS, which should be one of the WA_ERR_* values. It's rare to need to use this method, since generally any error return from the WebAuth C API is converted into a WebAuth::Exception and thrown instead, and the WebAuth::Exception object will contain a more detailed error message.

key_create (TYPE, SIZE[, KEY_MATERIAL])

Create a new WebAuth::Key object. TYPE currently must be WA_KEY_AES, and SIZE must be one of WA_AES_128, WA_AES_192, or WA_AES_256. This may change in the future if WebAuth gains support for additional key types.

If KEY_MATERIAL is given, it should contain SIZE bytes of data, which will be used as the key. If KEY_MATERIAL is not given or is undef, a new random key of the specified TYPE and SIZE will be generated.

The WebAuth::Key object will be destroyed when the WebAuth context used to create it is destroyed, and subsequent accesses to it may cause memory access errors or other serious bugs. Be careful not to retain a copy of a WebAuth::Key object after the WebAuth object that created it has been destroyed.

keyring_new (KEY)

keyring_new (SIZE)

Create a new WebAuth::Keyring object. This object holds WebAuth::Key objects and is used for token encryption and decryption.

The argument to this method may be either a WebAuth::Key object or a numeric size. If a WebAuth::Key object is provided, a new keyring containing only that key will be created and returned. If a size is provided, a new, empty keyring with space preallocated to hold that many keys is created and returned. (Regardless of the allocated size of a keyring, keyrings will always dynamically expand to hold any new keys that are added to them.)

The WebAuth::Keyring object will be destroyed when the WebAuth context used to create it is destroyed, and subsequent accesses to it may cause memory access errors or other serious bugs. Be careful not to retain a copy of a WebAuth::Keyring object after the WebAuth object that created it has been destroyed.

keyring_decode (DATA)

Create a new WebAuth::Keyring object by decoding DATA, which should be a keyring in its serialization format (as read from a file written by WebAuth::Keyring->write or encoded with WebAuth::Keyring->encode). All the caveats about the lifetime of the WebAuth::Keyring object mentioned for keyring_new() also apply here.

keyring_read (FILE)

Create a new WebAuth::Keyring object by reading its contents from the provided file. The created keyring object will have no association with the file after being created; it won't automatically be saved, or updated when the file changes. All the caveats about the lifetime of the WebAuth::Keyring object mentioned for keyring_new() also apply here.

krb5_new ()

Create a new WebAuth::Krb5 object and return it. This is used as a context for all Kerberos-related WebAuth calls. See WebAuth::Krb5 for supported methods.

token_decode (INPUT, KEYRING)

Given an encrypted and base64-encoded token, decode and decrypt it using the provided WebAuth::Keyring object. The return value will be a subclass of WebAuth::Token. See WebAuth::Token for common methods and a list of possible token object types.

Callers will normally want to check via isa() whether the returned token is of the type that the caller expected. Not performing that check can lead to security issues.

token_decrypt (INPUT, KEYRING)

Decrypt the input string, which should be raw encrypted token data (not base64-encoded), using the provided keyring and return the decrypted data.

This provides access to the low-level token decryption routine and should not normally be used. It's primarily available to aid in constructing test suites. token_decode() should normally be used instead.

token_encrypt (INPUT, KEYRING)

Encrypt the input string, which should be raw token attribute data, using the provided keyring and return the encrypted data. The encryption key used will be the one returned by the best_key() method of WebAuth::Keyring on that KEYRING.

This provides access to the low-level token encryption routine and should not normally be used. It's primarily available to aid in constructing test suites. A WebAuth::Token subclass and its encode() method should normally be used instead.

CONSTANTS

This module also provides a variety of API constants for the WebAuth library. WebAuth API status codes used both for API calls and for login errors and error tokens:

    WA_PEC_SERVICE_TOKEN_EXPIRED
    WA_PEC_SERVICE_TOKEN_INVALID
    WA_PEC_PROXY_TOKEN_EXPIRED
    WA_PEC_PROXY_TOKEN_INVALID
    WA_PEC_INVALID_REQUEST
    WA_PEC_UNAUTHORIZED
    WA_PEC_SERVER_FAILURE
    WA_PEC_REQUEST_TOKEN_STALE
    WA_PEC_REQUEST_TOKEN_INVALID
    WA_PEC_GET_CRED_FAILURE
    WA_PEC_REQUESTER_KRB5_CRED_INVALID
    WA_PEC_LOGIN_TOKEN_STALE
    WA_PEC_LOGIN_TOKEN_INVALID
    WA_PEC_LOGIN_FAILED
    WA_PEC_PROXY_TOKEN_REQUIRED
    WA_PEC_LOGIN_CANCELED
    WA_PEC_LOGIN_FORCED
    WA_PEC_USER_REJECTED
    WA_PEC_CREDS_EXPIRED
    WA_PEC_MULTIFACTOR_REQUIRED
    WA_PEC_MULTIFACTOR_UNAVAILABLE
    WA_PEC_LOGIN_REJECTED
    WA_PEC_LOA_UNAVAILABLE
    WA_PEC_AUTH_REJECTED
    WA_PEC_AUTH_REPLAY
    WA_PEC_AUTH_LOCKOUT
    WA_PEC_LOGIN_TIMEOUT

Status codes used only for API calls:

    WA_ERR_NONE
    WA_ERR_NO_ROOM
    WA_ERR_CORRUPT
    WA_ERR_NO_MEM
    WA_ERR_BAD_HMAC
    WA_ERR_RAND_FAILURE
    WA_ERR_BAD_KEY
    WA_ERR_FILE_OPENWRITE
    WA_ERR_FILE_WRITE
    WA_ERR_FILE_OPENREAD
    WA_ERR_FILE_READ
    WA_ERR_FILE_VERSION
    WA_ERR_NOT_FOUND
    WA_ERR_KRB5
    WA_ERR_INVALID_CONTEXT
    WA_ERR_TOKEN_EXPIRED
    WA_ERR_TOKEN_STALE
    WA_ERR_APR
    WA_ERR_UNIMPLEMENTED
    WA_ERR_INVALID
    WA_ERR_REMOTE_FAILURE
    WA_ERR_FILE_NOT_FOUND
    WA_ERR_TOKEN_REJECTED

Key types for key_create() and WebAuth::Key->new:

    WA_KEY_AES

Key sizes for key_create() and WebAuth::Key->new:

    WA_AES_128
    WA_AES_192
    WA_AES_256

Key usages for the best_key() method of WebAuth::Keyring:

    WA_KEY_DECRYPT
    WA_KEY_ENCRYPT

Canonicalization modes for the get_principal() and read_auth() methods of WebAuth::Krb5:

    WA_KRB5_CANON_NONE
    WA_KRB5_CANON_LOCAL
    WA_KRB5_CANON_STRIP

AUTHOR

Roland Schemers, Jon Robertson <jonrober@stanford.edu>, and Russ Allbery <eagle@eyrie.org>.