New Modular Authentication Architecture in Apache 2.2 and Beyond
Brad NicholesSr. Software Engineer, Novell Inc.Member, Apache Software [email protected]
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Agenda
• Introduction• Difference between Apache 2.0 and 2.2• Configuration
– Authentication and Authorization– Mix and match providers and methods
• Mod_authn_alias• Coding for the new architecture• New features already in Apache 2.3
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Introduction
• Authentication Type – Type of protocol 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
Terms / Authentication Elements:
Note: Pay close attention to the words Authentication vs. Authorization throughout the presentation
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What Are the Advantages?
• Flexibility:– Ability to choose between Authentication Type vs. Authentication Method vs.
Authorization Method– Ability to use multiple different authentication 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
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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
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New Modules – Authentication Type
Modules Directives
Mod_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
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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
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New Modules – Authentication Providers
Modules Directives
Mod_Authn_FileFile based user authentication
• AuthUserFile
Mod_Authnz_LDAPLDAP directory based authentication
• AuthLDAPBindDN• AuthLDAPBindPassword• AuthLDAPCharsetConfig• AuthLDAPDereferenceAliases• AuthLDAPRemoteUserIsDN• AuthLDAPUrl
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New Modules - Authorization
Modules Directives
Mod_Authnz_LDAPLDAP directory based authorization
• Require ldap-user• Require ldap-group• Require ldap-dn• Require ldap-attribute• Require ldap-filter • AuthLDAPCompareDNOnServer• AuthLDAPGroupAttribute• AuthLDAPGroupAttributeIsDN• AuthzLDAPAuthoritative
Mod_Authz_DefaultAuthorization fallback module
• AuthzDefaultAuthoritative
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New Modules - Authorization
Modules Directives
Mod_Authz_DBMDBM file based group authorization
• Require file-group*• Require group• AuthDBMGroupFile• AuthzDBMAuthoritative• 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
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New Modules - Authorization
Modules Directives
Mod_Authz_OwnerAuthorization based on file ownership
• Require file-owner• AuthzOwnerAuthoritative
Mod_Authz_UserUser authorization
• Require valid-user• Require user• AuthzUserAuthoritative
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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
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Differences – More Authorization Types
• Apache 2.0– Require Valid-User– Require User user-id [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
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“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 file system 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??)
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“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)
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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
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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 is group file based
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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 Require valid-user</Directory>
The authentication includes both file and LDAP providers with
the file provider taking
precedence followed by
LDAP
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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
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>
Check autorization according to
ldap-group OR file group
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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_authz_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
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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
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Creating Custom Providers
Use an <AuthnProviderAli
as> block to combine
authentication directives
LoadModule authn_alias_module modules/mod_authn_alias.so
<AuthnProviderAlias ldap ldap-alias1> AuthLDAPBindDN cn=youruser,o=ctx AuthLDAPBindPassword yourpassword AuthLDAPURL ldap://ldap.host/o=ctx</AuthnProviderAlias>
<AuthnProviderAlias ldap ldap-other-alias> AuthLDAPBindDN cn=yourotheruser,o=dev AuthLDAPBindPassword yourotherpassword AuthLDAPURL ldap://other.ldap.host/o=dev?cn</AuthnProviderAlias>
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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 in the AuthXXXProvider
directives
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Using Custom Providers
Whenever an Authn_alias provider is
referenced, the entire set of
AuthnProviderAlias directives are
added to the configuration
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_Placerequire valid-user
</Directory>
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Using Custom Providers
Creating Authn_alias
extended providers allows the “ldap”
base provider to be referenced multiple
times under different conditions,
from a single AuthBasicProvider
directive
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_Placerequire valid-user
</Directory>
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Converting Mod_Simple_Auth 2.0 to Apache 2.2
static int
check_user_access (request_rec *r) { /* Much of this code reimplements existing
authorization types */ for (x = 0; x < all_possible_authorization_types;
x++) { authorization_type =
all_possible_authorization_types[x];
if (!strcmp(authorization_type, "valid-user"))
return OK; if (!strcmp(authorization_type, "user")) { if (authorized_user) return OK; } if (!strcmp(authorization_type, "group")) { if (user_is_member_of_authorized_group) return OK; } if (!strcmp(authorization_type,
"simple-user") { if (authorized_simple_user) return OK; } } return HTTP_UNAUTHORIZED;}
static int
authenticate_basic_user(request_rec *r){ /* Locked into basic authentication
with this call */ ap_get_basic_auth_pw (r, &sent_pw);
/* Determine if the credentials are good and then send the appropriate response */
if (!good_credentials) { return HTTP_UNAUTHORIZED; }
return OK;}
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Converting Mod_Simple_Auth 2.0 to Apache 2.2
static void register_hooks (apr_pool_t *p) { ap_hook_check_user_id(authenticate_basic_user,
NULL,NULL,APR_HOOK_MIDDLE); ap_hook_auth_checker(check_user_access,
NULL,NULL,APR_HOOK_MIDDLE);}
module AP_MODULE_DECLARE_DATA auth_module = { STANDARD20_MODULE_STUFF, create_auth_dir_config, NULL, NULL, NULL, auth_cmds, register_hooks };
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Mod_Authn_Simple for Apache 2.2
static const authn_provider
authn_simple_provider ={ &check_password, /* password validation
function */ &get_realm_hash, /* digest hash function */};
static void register_hooks (apr_pool_t *p){ ap_register_provider(p, AUTHN_PROVIDER_GROUP,
"simple", "0", &authn_simple_provider);}
module AP_MODULE_DECLARE_DATA authn_simple_module={ STANDARD20_MODULE_STUFF, create_authn_simple_dir_config, NULL, NULL, NULL, authn_simple_cmds, register_hooks};
static authn_status check_password(request_rec *r, const char *user,
const char *password) { /* Determine if the credentials are
good and then send the appropriate response */ if (!good_credentials) return AUTH_DENIED; return AUTH_GRANTED;}
static authn_status get_realm_hash(request_rec *r, const char *user,
const char *realm, char **rethash) { /* Determine the hash and do the right
thing */ the_hash = determine_the_hash();
if (!the_hash) return AUTH_USER_NOT_FOUND;
*rethash = the_hash; return AUTH_USER_FOUND;}
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Mod_Authz_Simple for Apache 2.2static void
register_hooks (apr_pool_t *p)
{
ap_hook_auth_checker(check_user_access, NULL, NULL, APR_HOOK_MIDDLE);}
module AP_MODULE_DECLARE_DATA authz_simple_module ={ STANDARD20_MODULE_STUFF, create_authz_simple_dir_config, NULL, NULL, NULL, authz_simple_cmds,
register_hooks};
static int
check_user_access (request_rec *r)
{ for (x = 0; x < all_possible_authorization_types; x++) { authorization_type = all_possible_authorization_types[x];
if (!strcmp(authorization_type, "simple-user")) { if (authorized_simple_user) { return OK; } } }
/* If we aren't authoritative then just DECLINE */ if (!authoritative) return DECLINED;
/* Return the appropriate response */ return HTTP_UNAUTHORIZED;}
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New Features Already in Apache 2.3
• Moving from hook-based to provider-based authorization
• “AND/OR/NOT” logic in authorization• Host Access Control as an authorization type
– Require IP …, Require Host …, Require Env …– Require All Granted, Require All Denied– “Order Allow/Deny”, “Satisfy” where did they go?– Backward compatibility with the 2.0/2.2 Host Access Control,
use the Mod_Access_Compat module
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Mod_Authz_Simple Provider for Apache 2.3
static void
register_hooks (apr_pool_t *p){ ap_register_provider(p,
AUTHZ_PROVIDER_GROUP,
"simple-user", "0", &authz_simpleuser_provider);
}
module AP_MODULE_DECLARE_DATA authz_simple_module =
{ STANDARD20_MODULE_STUFF, create_authz_simple_dir_config, NULL, NULL, NULL, authz_simple_cmds,
register_hooks};
static authz_status
simple_user_authorization (request_rec *r,const char *require_args){ if (authorized_simple_user) { return AUTHZ_GRANTED; }
return AUTHZ_DENIED;}
static const authz_provider
authz_simpleuser_provider ={ &simple_user_authorization,};
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Authorization Types
Mod_Authnz_LDAP• LDAP-User• LDAP-Group• LDAP-DN• LDAP-Attribute• LDAP-Filter
Mod_Authz_Host• Env• IP• Host• All
Mod_Authz_DBD• DBD-Group• DBD-Login• DBD-Logout
Mod_Authz_Groupfile• Group• File-Group
Mod_Authz_DBM• DBM-Group• DBM-File-Group
Mod_Authz_User• User• Valid-User
Mod_Authz_Owner• File-Owner
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Adding “AND/OR/NOT” Logic to Authorization
• Allows authorization to be granted or denied based on a complex set of “Require…” statements
• New Directives– <SatisfyAll> … </SatisfyAll> - Must satisfy all of the
encapsulated statements– <SatisfyOne> … </SatisfyOne> - Must satisfy at least one of
the encapsulated statements– <RequireAlias> … </RequireAlias> - Defines a ‘Require’ alias– Reject – Reject all matching elements
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Authorization using ‘AND/OR’ Logic
Configuration<Directory /www/mydocs> Authname ... AuthType ... AuthBasicProvider ... ... Require user John <SatisfyAll> Require Group admins Require ldap-group cn=mygroup,o=foo
<SatisfyOne> Require ldap-attribute dept="sales“ Require file-group </SatisfyOne> </SatisfyAll>
</Directory>
Authorization Logic
if ((user == "John") ||
((Group == "admin") &&
(ldap-group <contains user>) &&
((ldap-attribute dept=="sales") ||
(file-group contains user))))then Authorization Grantedelse Authorization Denied
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Host Access Control as Authorization Types
Apache 2.3<Location …>
Require All Denied
</Location>
Apache 2.2<Location …>
Order Allow,Deny
Deny From All
</Location>
<Location …>
Require Host Apache.org
</Location>
<Location …>
Order Deny,Allow
Allow From Apache.org
</Location>
<Location …>
<SatisfyAll>
Require IP 10.1 172.5
Require env LET_ME_IN
</SatisfyAll>
<Location>
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Backwards Compatible Host Access Control with Mod_Access_Compat
• The directives “Order Allow/Deny” and “Satisfy” are still available with Mod_Access_Compat
• Mod_Access_Compat will allow you to mix the new authorization types with the old host access control
• Mod_Authn_Default and Mod_Authz_Default modules must be loaded
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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 authentication providers• Reuse the same authentication base provider under different conditions
from the same AuthnxxxProvider directive• Much more powerful, flexible and consistent• More to come in Apache 2.3!
General Disclaimer
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