April 20, 2023

New Modular Authenication Architecture in Apache 2.2

Brad NicholesSenior Software Engineer, Novell, Inc.Member, Apache Software Foundation bnicholes@novell.com

© 2005 Novell Inc

2

Agenda

• Introduction• Advantages• New Modules• Difference between Apache 2.0 and 2.2• Configuration

• Authentication and Authorization• Mix and match providers and methods

• Mod_authn_alias• Conclusion

© 2005 Novell Inc

3

Introduction

Terms / Authentication Elements:• Authentication Type – Type of encryption used during

transport of the authentication credentials (Basic or Digest)• Authentication Method/Provider - Process by which a user

is verified to be who they say they are• Authorization - Process by which authenticated users are

granted or denied access based on specific criteria

Previous to Apache 2.2, every authentication module had to implement all three elements

• Choosing an AuthType limited which authentication and authorization methods could be used

• Potential for inconsistencies across authentication modules

Note: Pay close attention to the words Authentication vs. Authorization through out the presentation

© 2005 Novell Inc

4

What Are The Advantages?

• Flexibility: • Ability to choose between Authentication Type vs. Authentication Method

vs. Authorization Method• Ability to use multiple different authorization methods• Mixing and matching is not a problem

• Consistency: • Authorization methods are guaranteed to work the same no matter which

authentication method is chosen• Ability to use the same authentication and authorization methods for all

authentication types

• Reuse: • Implementing a new authentication provider module does not require the

reimplementation or duplication of existing authorization methods • The inverse of the above statement is also true• Ability to create your own custom authentication providers and reuse them

throughout your configuration

© 2005 Novell Inc

5

New Modules - Introduction

• The functionality of each Apache 2.0 authentication module has been split out into the three authentication elements for Apache 2.2

• Overlapping functionality among the modules was simply eliminated in favor of a base implementation

• The module name indicates which element of the authentication functionality it performs

• Mod_auth_xxx – Implements an Authentication Type• Mod_authn_xxx – Implements an Authentication Method or

Provider• Mod_authz_xxx – Implements an Authorization Method

© 2005 Novell Inc

6

New Modules – Authentication Type

Modules DirectivesMod_Auth_BasicBasic authentication – User credentials are received by the server as unencrypted data

• AuthBasicAuthoritative• AuthBasicProvider

Mod_Auth_DigestMD5 Digest authentication – User credentials are received by the server in encrypted format

• AuthDigestAlgorithm• AuthDigestDomain• AuthDigestNcCheck• AuthDigestNonceFormat• AuthDigestNonceLifetime• AuthDigestProvider• AuthDigestQop• AuthDigestShmemSize

© 2005 Novell Inc

7

New Modules – Authentication Providers

Modules Directives

Mod_Authn_AnonAllows “anonymous” user access to authenticated areas

• Anonymous• Anonymous_LogEmail• Anonymous_MustGiveEmail• Anonymous_NoUserID

• Anonymous_VerifyEmail Mod_Authn_DBMDBM file based user authentication

• AuthDBMType

• AuthDBMUserFile Mod_Authn_DefaultAuthentication fallback module

• AuthDefaultAuthoritative

© 2005 Novell Inc

8

New Modules – Authentication Providers

Modules Directives

Mod_Authn_FileFile based user authentication

• AuthUserFile

Mod_Authnz_LDAPLDAP directory based authentication

• AuthLDAPBindDN• AuthLDAPBindPassword• AuthLDAPCharsetConfig• AuthLDAPDereferenceAliases• AuthLDAPUrl

© 2005 Novell Inc

9

New Modules – Authorization

Modules DirectivesMod_Authnz_LDAPLDAP directory based authorization

• Require ldap-user• Require ldap-group• Require ldap-dn• Require ldap-attribute

• Require ldap-filter • AuthLDAPCompareDNOnServer• AuthLDAPGroupAttribute• AuthLDAPGroupAttributeIsDN• AuthLDAPRemoteUserIsDN• AuthzLDAPAuthoritative

Mod_Authz_DefaultAuthorization fallback module

• AuthzDefaultAuthoritative

© 2005 Novell Inc

10

New Modules – Authorization

Modules DirectivesMod_Authz_DBMDBM file based group authorization

• Require file-group*• Require group• AuthDBMGroupFile• AuthDBMAuthoritative

• AuthzDBMType Mod_Authz_GroupFileFile based group authorization

• Require file-group*• Require group• AuthGroupFile

• AuthzGroupFileAuthoritative Mod_Authz_HostGroup authorization based on host (name or IP address)

• Allow• Deny

• Order

© 2005 Novell Inc

11

New Modules – Authorization

Modules DirectivesMod_Authz_OwnerAuthorization based on file ownership

• Require file-owner• AuthzOwnerAuthoritative

Mod_Authz_UserUser authorization

• Require valid-user• Require user• AuthzUserAuthoritative

© 2005 Novell Inc

12

Differences Between Apache 2.0 & 2.2

• New Directives• AuthBasicProvider On|Off|provider-name [provider-name] ...• AuthDigestProvider On|Off|provider-name [provider-name] ... • AuthzXXXAuthoritative On|Off

• Renamed Directives• AuthBasicAuthoritative On|Off

• Multiple modules must be loaded (auth, authn, authz) rather than a single mod_auth_xxx module

© 2005 Novell Inc

13

Differences - More Authorization Types

• Apache 2.0• Require Valid-User• Require User userid [user-id] …• Require Group group-name [group-name] …

• Apache 2.2• Same as Apache 2.0• LDAP - ldap-user, ldap-group, ldap-dn, ldap-filter, ldap-attribute • GroupFile - file-group*• DBM - file-group*• Owner - file-owner

• Since multiple authorization methods can be used, in most cases the type names should be unique

© 2005 Novell Inc

14

“file-group” Authorization Type

• Unique because it depends on the Authz_Owner module for base functionality but other Authz_xxx modules to do the work

• Allows authorization based on group membership• Implemented in Apache 1.3.20 but missing from

Apache 2.0• The authenticated user must be a member of the

group to which the requested file belongs• The group name is derived from the group

permission of the requested file• Authorization is actually performed by secondary

authz modules (Mod_Authz_Groupfile, Mod_Authz_DBM, others??)

© 2005 Novell Inc

15

“ldap-xxx” Authorization Types

• The standard types, ldap-user, ldap-group and ldap-dn were renamed to avoid conflicts and for consistency

• New LDAP authorization types• ldap-attribute allows the administrator to grant access based on

attributes of the authenticated user in the LDAP directory. If multiple attributes are listed then the result is an ‘OR’ operation.

– require ldap-attribute city="San Jose" status=active

• ldap-filter allows the administrator to grant access based on a complex LDAP search filter. If the dn returned by the filter search matches the authenticated user dn, access is granted.

– require ldap-filter &(cell=*)(department=marketing)

© 2005 Novell Inc

16

Configuring Simple Authentication

LoadModule auth_basic_module modules/mod_auth_basic.soLoadModule authn_file_module modules/mod_authn_file.soLoadModule authz_user_module modules/mod_authz_user.soLoadModule authz_host_module modules/mod_authz_host.so

<Directory /www/docs> Order deny,allow Allow from all AuthType Basic AuthName Authentication_Test AuthBasicProvider file AuthUserFile /www/users/users.dat require valid-user</Directory>

The authentication provider is file based and the authorization method is any

valid-user

© 2005 Novell Inc

17

Requiring Group Authorization

LoadModule auth_basic_module modules/mod_auth_basic.soLoadModule authn_file_module modules/mod_authn_file.so#LoadModule authz_user_module modules/mod_authz_user.soLoadModule authz_host_module modules/mod_authz_host.soLoadModule authz_groupfile_module modules/mod_authz_groupfile.so

<Directory /www/docs> Order deny,allow Allow from all AuthType Basic AuthName Authentication_Test AuthBasicProvider file AuthUserFile /www/users/users.dat

AuthGroupFile /www/users/group.dat require group my-valid-group</Directory>

The authentication provider is file based but the authorization

method now is group file based

© 2005 Novell Inc

18

Multiple Authentication Providers

LoadModule auth_basic_module modules/mod_auth_basic.soLoadModule authn_file_module modules/mod_authn_file.soLoadModule authz_user_module modules/mod_authz_user.soLoadModule authz_host_module modules/mod_authz_host.soLoadModule authnz_ldap_module modules/mod_authnz_ldap.soLoadModule ldap_module modules/mod_ldap.so

<Directory /www/docs> Order deny,allow Allow from all AuthType Basic AuthName Authentication_Test AuthBasicProvider file ldap AuthUserFile /www/users/users.dat AuthLDAPURL ldap://ldap.server.com/o=my-context AuthzLDAPAuthoritative off require valid-user</Directory>

The authentication now includes both file and

LDAP providers with the file

provider taking precedence followed by

LDAP

© 2005 Novell Inc

19

Multiple Authorization Methods

LoadModule auth_basic_module modules/mod_auth_basic.soLoadModule authn_file_module modules/mod_authn_file.so#LoadModule authz_user_module modules/mod_authz_user.soLoadModule authz_host_module modules/mod_authz_host.soLoadModule authz_groupfile_module modules/mod_authz_groupfile.soLoadModule authnz_ldap_module modules/mod_authnz_ldap.soLoadModule ldap_module modules/mod_ldap.so

<Directory /www/docs> Order deny,allow Allow from all AuthType Basic AuthName Authentication_Test AuthBasicProvider file AuthUserFile /www/users/users.dat

AuthzLDAPAuthoritative OFF AuthGroupFile /www/users/group.dat AuthLDAPURL ldap://ldap.server.com/o=my-context require ldap-group cn=public-users,o=my-context require group my-valid-group</Directory>

Set AuthzLDAPAuthoritative to “OFF” to allow the

LDAP authorization method to defer if

necessary

© 2005 Novell Inc

20

file-group Authorization

LoadModule auth_basic_module modules/mod_auth_basic.soLoadModule authn_file_module modules/mod_authn_file.soLoadModule authz_host_module modules/mod_authz_host.soLoadModule authz_groupfile_module modules/mod_authz_groupfile.soLoadModule authnz_owner_module modules/mod_authnz_owner.so

<Directory /www/docs> Order deny,allow Allow from all AuthType Basic AuthName Authentication_Test AuthBasicProvider file AuthUserFile /www/users/users.dat

AuthGroupFile /www/users/group.dat require file-group</Directory>

The group that the user belongs to that is

defined by the AuthGroupFile must match the actual file

group of the requested file

© 2005 Novell Inc

21

Introduction – Mod_Authn_Alias

• Ability to create extended providers• Ability to reference the same base provider multiple

times from a single AuthnxxxProvider directive• Extended providers are assigned a new name or

Alias• Extended provider aliases are referenced by the

directives AuthBasicProvider or AuthDigestProvider in the same manner as base providers

• Extended providers can be re-referenced by multiple configuration blocks

© 2005 Novell Inc

22

Creating Custom Providers

LoadModule authn_alias_module modules/mod_authn_alias.so

<AuthnProviderAlias ldap ldap-alias1>AuthLDAPBindDN cn=youruser,o=ctxAuthLDAPBindPassword yourpasswordAuthLDAPURL ldap://ldap.host/o=ctx

</AuthnProviderAlias>

<AuthnProviderAlias ldap ldap-other-alias>AuthLDAPBindDN cn=yourotheruser,o=devAuthLDAPBindPassword yourotherpasswordAuthLDAPURL ldap://other.ldap.host/o=dev?cn

</AuthnProviderAlias>

Use an <AuthnProviderAlia

s> block to combine

authentication directives together

© 2005 Novell Inc

23

Creating Custom Providers

LoadModule authn_alias_module modules/mod_authn_alias.so

<AuthnProviderAlias ldap ldap-alias1>AuthLDAPBindDN cn=youruser,o=ctxAuthLDAPBindPassword yourpasswordAuthLDAPURL ldap://ldap.host/o=ctx

</AuthnProviderAlias>

<AuthnProviderAlias ldap ldap-other-alias>AuthLDAPBindDN cn=yourotheruser,o=devAuthLDAPBindPassword yourotherpasswordAuthLDAPURL ldap://other.ldap.host/o=dev?cn

</AuthnProviderAlias>

Each <AuthnProviderAlia

s> block references the

base provider and assigns a provider alias that will be

referenced by the AuthxxxProvider

directives

© 2005 Novell Inc

24

Using Custom Providers

LoadModule auth_basic_module modules/mod_auth_basic.soLoadModule authz_host_module modules/mod_authz_host.soLoadModule authz_user_module modules/mod_authz_user.soLoadModule authnz_ldap_module modules/mod_authnz_ldap.soLoadModule ldap_module modules/mod_ldap.so

<Directory /webpages/secure>Order deny,allowAllow from all

AuthBasicProvider ldap-other-alias ldap-alias1

AuthType BasicAuthName LDAP_Protected_PlaceAuthzLDAPAuthoritative offrequire valid-user

</Directory>

Whenever an Authn_alias provider is

referenced, the entire set of

AuthnProviderAlias directives are

added to the configuration

© 2005 Novell Inc

25

Using Custom Providers

LoadModule auth_basic_module modules/mod_auth_basic.soLoadModule authz_host_module modules/mod_authz_host.soLoadModule authz_user_module modules/mod_authz_user.soLoadModule authnz_ldap_module modules/mod_authnz_ldap.soLoadModule ldap_module modules/mod_ldap.so

<Directory /webpages/secure>Order deny,allowAllow from all

AuthBasicProvider ldap-other-alias ldap-alias1

AuthType BasicAuthName LDAP_Protected_PlaceAuthzLDAPAuthoritative offrequire valid-user

</Directory>

Creating Authn_alias

extended providers allows the “ldap”

base provider to be reference multiple

times under different conditions,

from a single AuthBasicProvider

directive

© 2005 Novell Inc

26

Summary

• Choosing the way authentication and authorization is done is now more modular

• No longer bound to a specific authentication method based on authentication type

• No longer bound to an authorization method based on the chosen authentication module

• Ability to use multiple authentication providers along with multiple different authorization methods

• Create, use and reuse custom authorization providers• Reuse the same authentication base provider under different

conditions from the same AuthnxxxProvider directive• Much more powerful, flexible and consistent

Questions