I'm trying to use the ldap_sasl_bind_s method from the Microsoft LDAP C SDK, with GSSAPI as the authentication mechanism. ldap_sasl_bind_s expects the credentials as a BERVAL structure, which is opaque.
Given a username (or a DN) and a password, how do I get to the BERVAL structure that I'm supposed to pass to ldap_sasl_bind_s?
The examples I've found so far
are from other LDAP C SDKs - not the one from Microsoft
use ldap_sasl_bind_s when SIMPLE authentication is desired - but I need to use GSSAPI
use ldap_sasl_interactive_bind_s when other SASL authentication mechanisms are desired. However, there is no ldap_sasl_interactive_bind_s in the Microsoft SDK.
As a side note, the goal is to be able to bind over SASL to a variety of LDAP servers; for now: ActiveDirectory and OpenLDAP.
Any pointers will be greatly appreciated.
I managed to perform an LDAP SASL bind over GSSAPI, using ldap_sasl_bind_s. For those interested, here are some pointers.
For an abstract description of the actions a client and server need to perform during a GSSAPI SASL authentication, "The Kerberos V5 ("GSSAPI") Simple Authentication and Security Layer (SASL) Mechanism" RFC should be read; specifically, the 'Client Side of Authentication Protocol Exchange' section is of interest, because it gives an indication of the sequence of actions we need to perform to successfully bind to an LDAP server over Kerberos.
The credentials ldap_sasl_bind_s expects - their form and their meaning - depend on the actual authentication mechanism being used, which in our case is Kerberos.
In the Microsoft SDK, Kerberos is available through SSPI - which is roughly the Microsoft implementation of GSSAPI; the methods that are relevant for our particular case are: AcquireCredentialsHandle, InitializeSecurityContext, DecryptMessage, EncryptMessage
An LDAP SASL bind over Kerberos has 3 phases.
Phase 1
Call AcquireCredentialsHandle and InitializeSecurityContext.
Important notes here:
pass to AcquireCredentialsHandle a pointer to a SEC_WINNT_AUTH_IDENTITY structure containing the actual credentials (realm, username, password), or NULL if the credentials of the current thread are to be used
the target name should be an SPN mapped to the account under which the LDAP server is running
when calling InitializeSecurityContext, mutual authentication must be requested.
If all important arguments are correct - valid credentials, valid SPN, NULL input token - the InitializeSecurityContext call should return SEC_I_CONTINUE_NEEDED and properly fill the output token. The contents of this output token should go in the BERVAL structure ldap_sasl_bind_s expects as client credentials.
Call ldap_sasl_bind_s with the output token from InitializeSecurityContext as client credentials. If all arguments are correct - empty DN, GSSAPI as the mechanism name - the actual call should return LDAP_SUCCESS and the most recent LDAP error for the LDAP session should be LDAP_SASL_BIND_IN_PROGRESS.
As a side note, the most recent LDAP error for an LDAP session can be discovered by calling ldap_get_option on the session, with LDAP_OPT_ERROR_NUMBER as the option.
Phase 2
After the successful call to ldap_sasl_bind_s, its last argument points to a BERVAL structure containing the server credentials. The content of this BERVAL structure should now be used as the input token for the second call to InitializeSecurityContext.
This second call to InitializeSecurityContext should return SEC_OK and an empty output token.
This empty output token should be used as the client credentials for another call to ldap_sasl_bind_s. This second call to ldap_sasl_bind_s should return LDAP_SUCCESS, with the most recent LDAP error for the LDAP session being LDAP_SASL_BIND_IN_PROGRESS.
Phase 3
After the second successful call to ldap_sasl_bind_s, its last argument points to a BERVAL structure containing server data. This server data should be given as input to DecryptMessage. As specified in the previously mentioned RFC, the decrypted data must be 4 bytes long.
The client should build its reply according to the information in the same RFC.
Note: In my case, I omitted the authorization id mentioned in the RFC. To my understanding, an empty authorization id leads to the authentication id being used for authorization as well.
The reply the client built should then be passed as input to EncryptMessage. The output of the EncryptMessage call should then be passed as the client credentials for the third and final call to ldap_sasl_bind_s.
Note: The MSDN documentation for using EncryptMessage under Kerberos seems to be incomplete. Google's Code Search should assist with a working example. Also, for a working example of the flow described above, Samba's source code can be consulted.
I found the problem.
According to this thread ( https://groups.google.com/group/microsoft.public.active.directory.interfaces/browse_thread/thread/9c13fe85e520f0b4/820a136e032946e9?pli=1) there is a bug with ldap_sasl_bind_s returning empty server credentials in Windows XP. I have tested my application under Windows 2008 Server and the credentials are properly returned.
Article from Sun and MSDN. Probably if you can try creating a sample program you may get the answers
Another One
PseudoCode
struct berval cred;
char mechanism[BUFSIZ];
getline( mechanism, sizeof(mechanism), stdin, "mechanism? " );
getline( passwd, sizeof(passwd), stdin,"credentials? " );
cred.bv_val = passwd;
cred.bv_len = strlen( passwd );
rc = ldap_sasl_bind_s( ld, dn, mechanism, &cred, NULL, NULL, NULL );
Related
IdentityModelEventSource has a property called ShowPII that means that Personally Identifiable Information will be added to the logs (in relation to security). This value is used to decide when to log some OAuth2 sensitive data.
I am trying to understand what kind of Personally Identifiable Information will be logged:
Client ID? (aka Client Key, Consumer Key)
Client Secret? (aka Consumer Secret)
Json Web Tokens? (aka JWT)
Access Tokens?
Refresh Tokens?
Kerberos Tickets?
PKCE Values?
Authorization Codes?
I know it cannot get access to usernames and passwords because they are only exchanged directly with the IDP.
But but I need to know if I need to find a way to lock down my log files because it will have data that constitutes a security vulnerability.
This is possible log messages of IdentityModel: LogMessages.cs
About
I am trying to understand what kind of Personally Identifiable Information will be logged
I won't copy-paste log messages from there (especially, as they can change at any moment). You can check them yourself and decide what should be considered as the PII.
But here's an interesting example:
"IDX10615: Encryption failed. No support for: Algorithm: '{0}', SecurityKey: '{1}'."
and this is how it's used:
throw LogHelper.LogExceptionMessage(new SecurityTokenEncryptionFailedException(LogHelper.FormatInvariant(TokenLogMessages.IDX10615, encryptingCredentials.Enc, encryptingCredentials.Key)));
If you'll follow the track you'll find out that encryptingCredentials.Key will be logged if ShowPII = true and won't be logged if ShowPII = false.
Of course, depending on your use case, this particular message may never appear in your logs. And not all messages so outrageously leaky. But you never know:
your use case may change
you may be mistaken about the set of messages IdentityModel can emit for your use case
IdentityModel code may change, and you may forget to check if messages' set is still secure
So about
if I need to find a way to lock down my log files
Yes, you definitely need to.
Or better yet - don't use ShowPII = true in production for monitoring, use it only in development environment for debugging purposes.
Looking at the source, it appears that when ShowPII is on - it will do two things:
Replace all parameters passed to library-specific exceptions with their data type names
For all system exceptions - replace inner message with exception type name
In this context "library-specific" is an exception that is of type Exception and its full type name starts with "Microsoft.IdentityModel." (library defines a few)
Depending on your use case you'd see a variety of parameters that can be logged with custom exceptions. A quick search for FormatInvariant yields quite a few for your consideration.
Again, depending on how you use it, you might get a better idea of what the error messages are by looking through relevant LogMessages.cs file on your specific namespace.
P.S.: on a side note, it appears that default ShowPII setting is GDPR-compliant
When a user want to register his device, the relying party provide some parameters which are :
a challenge,
appID,
Version of protocol
The user performs then a "user presence test" by touching the button on his device sending those informations :
dictionary RegisterResponse {
DOMString registrationData;
DOMString clientData;
};
Relying party do what he has to do with those informations and the process is finished !
But I do not understand the following part. Based on the specifications of U2F protocol :
Registration Request Message - U2F_REGISTER
This message is used to initiate a U2F token registration. The FIDO Client first contacts the relying party to obtain a challenge, and then constructs the registration request message. The registration request message has two parts:
The challenge parameter is the SHA-256 hash of the Client Data, a stringified JSON data structure that the FIDO Client prepares. Among other things, the Client Data contains the challenge from the relying party (hence the name of the parameter).
The application parameter [32 bytes]. The application parameter is the SHA-256 hash of the application identity of the application requesting the registration. (See [FIDOAppIDAndFacets] in bibliography for details.)
https://fidoalliance.org/specs/fido-u2f-v1.0-nfc-bt-amendment-20150514/fido-u2f-raw-message-formats.html
At which step this part is run ?
Thank you in advance !
You are talking about registration so linking a key to an account. To register a key:
The user types in name/password and posts to the server.
The server replies with RegisterRequestData (created with the server side u2f library).
The client side uses library function u2f.register which gives the request to the U2F device and gets back a RegisterResponse (json with the device registration info). This is send back to the server.
The server gives the reply to the serverside u2f library and saves the DeviceRegistration.
Authentication/login is similar but with the server sending DeviceRegistration + challenge to the client which uses u2f.sign and returns the DeviceResponse.
A schema that makes it clear I think:
https://developers.yubico.com/U2F/Libraries/Using_a_library.html
According to comment and a criticism for question being too broad; I'll try to make it more specific;
Environment - Server: autobahn|python with twisted, wampv2
Given that:
a) I have a class which extends RouterSession and authenticates user, and at the moment of authentification knows who the user accessing the wamp service is;
and
b) I have a class which extends ApplicationSession and on creation exposes several rpc methods through wamp
How do I access the user data in the exposed RPC method. By the user data - I mean - which I verified at the beginning of a specific client connection through RouterSession.
Because ApplicationSessions are initiated only once, and don't have a clue about caller (from what I have seen in debugger).
The reason I would need this - is to execute the rpc call with the context of a calling user. Where method's result might depend on specific user profile properties.
I am probably looking for something which could represent per-connection created Application instances (which could then hold reference to authorization result and data). Like most of the server Protocols operate in twisted.
-----------------ORIGINAL POST-----------
Brief question: imagine a scenario where user rights are based not on method but object; Example - I may have right to edit my profile account and profile accounts of my subordinates but not any other. This leaves to a situation where I would expose "com.myorg.profile.update_profile_details" RPC through WAMP to everyone, but would have to check which user is trying to modify which profile.
I see there is a validate mechanism in WAMP Router to deal with validating request - but it seems, that it lacks a reference to previous authentication result or session.
I really would like to avoid passing session keys (or, god forbid auth tokens) back and forth through the WAMP; whats the suggested approach for this?
----------------END OF ORIGINAL POST----------
After debugging traces back and forth, I found a solution which fits me - the trick is to pass additional options parameter when registering RPC methods:
self.register(self.test_me_now, 'com.ossnet.testme', options = RegisterOptions(details_arg = 'details', discloseCaller = True))
and voila - there is a new incoming parameter into registered RPC method: 'details'
with following contents:
CallDetails: CallDetails(progress = None, caller = 774234234575675677138, authid = johan.gram, authrole = user, authmethod = ticket)
When asking this question I am looking for guidance with implementation of my own AuthenticationProvider. By that i mean the following:
Till now i have learned that Spring Security ask the AuthenticationProvider object if the user is authenticated or not. Currently i am using the
DaoAuthenticationProvider wich process the username and the password that is beeing returned by my own custome UserDetailService. All works great!
Spring support a lot of different AuthenticationProvider's for example there is one for LDAP, Jdbc, DAO (as mentioned above) and i was even able to find one for Kerberos. However there is no authentication provider for SRP, thus the need to write one.
My question is here the following:
When we use the DaoAuthenticationProvider i.e. user/password authentication, we have a html form where the username and password are entered and then a button is responsible for submiting those 2 parameters. Bought barameteres are transfered over some transport channel to the server i.e. with one click we are able to send all of the data within the same http reqest i.e. all that is needed for the authentication. That can be seen in the UsernamePasswordAuthenticationFilter. Here the method "attemptAuthentication" takes "HttpServletRequest request" which includes username and password. Till now all good.
public Authentication attemptAuthentication(HttpServletRequest request, HttpServletResponse response) throws AuthenticationException {
...
}
Well, in the simple in SRP we have also a form that has a username and password, except the password !!!MUST!!! not be transfered over the network. In order to achieve that constrain a "discussion" between the client and the server has to take place i.e. the following parameters must be exchanged.
1) username (I),
2) a value called "A"
3) a value called "B"
4) a value called "M1"
5) a value called "M2"
Well, let us assume that there is a filter called "SrpAuthenticationProcessingFilter" how should the filter look like if the new authentication protocol was more like a conversation by that i mean from the RFC 5054.
Client Server
Client Hello (I) -------->
Server Hello
Certificate*
Server Key Exchange (N, g, s, B)
<-------- Server Hello Done
Client Key Exchange (A) -------->
[Change cipher spec]
Finished -------->
[Change cipher spec]
<-------- Finished
Application Data <-------> Application Data
Here we have a client that needs to
a) send first his username (I)
b) then the server needs to respond with a value B. (N,g,s are not really necessary in this case)
c) the client sends it's "value A"
d) the the client uses that value B from the server and based on that value calculates a key.
e) the server calculates the key as well based on the value A.
f) the client sends value M1 to the server.
g) the server gets the M1 value and based on a formula which has the M1 value as argument, he is able to verify if the keys
match, if the calculated keys of the bought sides match then the
user is authenticated, and the product i.e. the shared key could
be used further for other processing.
In a contrast to username and password authentication those are 7 steps not one. And 3 of those needs to happen before the SrpAuthenticationProcessingFilter. Now i am aware that there is a possibility to send the username together with the "value A" thus shortening the number of steps, but i would like to strictly follow the RFC. Never take the easy way right?
The question really is where do i place that code which is responcible for the ping pong (conversation) between the client and the server i.e. the first 3 steps a,b and c mentioned above. Should it place them in a SrpEntryPoint object, or somewhere else. if else then were in the context of SpringSecurity?
One way i can thing of solving this is using websockets, but i would also like to make that authentication independent from any layer 5-7 protocol such as websockets, http, spdy etc. . That means that the first implementation should be be trough simple http request/responce and then with any other protocol.
So the structure that could be the right one in order to implement SRP currently is:
SRPAuthenticationEntryPoint implements org.springframework.security.web.AuthenticationEntryPoint - this basically says what should be done if a request for a protected resource gets in, but the user is not authenticated yet. Here we can place a redirect in the case the resource has not been authenticated. Maybe this is also the place which is responsible for the steps a,b,c not sure if that is the right place. Request guidance and information!!
SrpAuthenticationProcessingFilter extends GenericFilterBean. SrpAuthenticationProcessingFilter exists to make partial validation for example to check if the srp paramters received a correct and corrspoding to the srp parameters that the server sets. Here it is important to mention that SrpAuthenticationProcessingFilter is not doing any username validation i.e. that needs to happen in one step before the SrpAuthenticationProcessingFilter is beeing called, maybe that is the SrpEntryPoint or some other step that i do not know how to call it yet. SrpAuthenticationProcessingFilter has a method "doFilter" in which the second structure is beeing created i.e. SrpAuthenticationToken.
SrpAuthenticationToken extend org.springframework.security.authentication.AbstractAuthenticationToken. That token in my understanding is something similar ot the DAO object, the token maps all field needed for sucessefull authentication. When partially validated parameters are populated into the SrpAuthenticationToken that SrpAuthenticationToken is passed to the authenticat method of the org.springframework.security.authentication.AuthenticationManager interface i.e. something like that
myAuthentication = authenticationManager.authenticate(SrpAuthenticationToken);
depending on which Authentication Provider is configured in the Spring Security config then the SrpAuthentication provider is called in our case i.e.:
#Autowired
public void registerAuthentication(AuthenticationManagerBuilder auth) throws Exception {
auth
.authenticationProvider(sRPAuthenticationProvider);
}
SRPAuthenticationProvider - implements org.springframework.security.authentication.AuthenticationProvider. Over here the steps d,e,f and g are being validated and compared. If something wrong happens then throw new BadCredentialsException("Invalid username/password/Verifiere") exception.
SrpSessionValidator - this one is responsible only for validating particular parameters of the Srp session and would be called from SrpAuthenticationProcessingFilter as well as in one step before the SrpAuthenticationProcessingFilter in order to validate if the username exists in the database at all.
I only have a general idea how to implement that Srp authentication, and thus i would like some comments if that makes sense at all and if SRPAuthenticationEntryPoint is the right place for the steps a,b and c. It does not feel like the right place to me.
Any feedback is greatly appreciated.
regards,
Tito
Addition1 (21 November 2014) -> As an aswer to the question "where to place that code which is responsible for the ping pong (conversation) between the client and the server i.e. the first 3 steps a,b and c " the answer to that would be most likely a standard (i will call it negotiation) filter which will take that job.
Now I would like to rephrase the question i.e. before the authentication is complete and before the M1 and M2 messages are received i.e. steps 1 2 and 3. Where do i place that object? I.e. it should be a place where the object should live for example for 60 seconds and then be automatically deleted in case no M1 and M2 messages has been received. I mean some object before the "SecurityContextHolder" object. I just do not know what is the name of that object/context related to spring security, also i do not know if such construct exists at all?
My approach would be to use AJAX to run the first parts of the protocol up to the creation of A and M1 at the client then post those to the server as the login credentials and check those using Spring Security.
To see how this works there is a junit-js test which runs mutual authentication between a javascript client object and a java server object using Thinbus over at TestSRP6JavascriptClientSessionSHA256.js (note the maven build runs this unit test using the JDK javascript runtime):
// note the following exchange is written in javascript calling client js and invoking server java which is run by JUnit-JS using the JDK javascript runtime so it shows both sides of the full authentication in one unit test method
// normal login flow step1a client: browser starts with username and password given by user at the browser
client.step1(username,password);
// normal login flow step1b server: server starts with username from browser plus salt and verifier saved to database on user registration.
var B = server.step1(username, salt, v);
// normal login flow step2a client: server sends users salt from user registration and the server ephemeral number
var credentials = client.step2(salt, B);
// normal login flow step2b server: client sends its client ephemeral number and proof of a shared session key derived from both ephermal numbers and the password
var M2 = server.step2(credentials.A, credentials.M1);
// normal login flow step3 client: client verifies that the server shows proof of the shared session key which demonstrates that it knows actual verifier
client.step3(M2);
Clearly the javascript client starts with only username and password. The server uses the username to resolve the salt and generates a random B. The client is given salt and B from the server and generates its random A and the M1 which is the password proof. The server step2 which takes M1 as a parameter is the server checking the user password proof and it will throw an exception if the proof is bad. The server then sends M2 which is the server proof that it has the user verifier v which is done to prevent a fake server spoofing the real server.
There is a demo of a browser doing SRP to a Java server over AJAX using Thinbus over at thinbus-srp-js-demo. You could re-use the JAX RS with AJAX approach (e.g. Spring MVC AJAX) to perform the first steps up to the creation of A+M1 at the client then post those to Spring Security using the login form post and have Spring Security verify A+M1 by running step2 on the server object as shown in the junit-js test. Then your AuthenticationManager could resolve the server object created by AJAX from a concurrent map keyed by username.
One minor note is that I would consider checking the server proof M2 as optional if you are using HTTPS to a server. If you are not using HTTPS then server spoofing means they can give the user a page which sends the password and ignores a bad M2; so the M2 proof doesn't provide security in the context of webpages. A mobile app which packages the html/js into a native app using something like phone gap would benefit from an M2 check; it can be added into the page after the user is logged in to be checked by the trusted code.
There is a spring security SRP implimentation at https://bitbucket.org/simon_massey/thinbus-srp-spring-demo
The readme page says:
A salient feature of the integration is that there are no changes to
the standard spring security authentication path other than to
configure the custom SrpAuthenticationProvider.
It also says:
Spring Security does not expose the user HTTPSession to the
AuthenticationProvider. So demo code uses a Guava cache with a timeout
to hold the SRP6JavascriptServerSession for the brief period of the
login exchange. As of Thinbus 1.2.1 the session is serialisable so an
alternative approach for a large stateless website would be to hold
the SRP6JavascriptServerSession object in the DB rather than in an
in-memory cache.
We are getting the following error:
org.apache.axis2.AxisFault: System.Web.Services.Protocols.SoapException: Server was unable to process request. ---> D2L.WS.Security.Authentication.AuthenticationException: Expired authentication token
at D2L.WS.Security.Authentication.TokenAuthenticator.AuthententicateHeader(Int64 orgId, RequestHeaderInfo headerInfo)
at D2L.WS.Implementation.SoapHeaderServiceBase`1.set_RequestHeader(RequestHeaderInfo value)
--- End of inner exception stack trace ---
at org.apache.axis2.util.Utils.getInboundFaultFromMessageContext(Utils.java:446)
at org.apache.axis2.description.OutInAxisOperationClient.handleResponse(OutInAxisOperation.java:371)
at org.apache.axis2.description.OutInAxisOperationClient.send(OutInAxisOperation.java:417)
at org.apache.axis2.description.OutInAxisOperationClient.executeImpl(OutInAxisOperation.java:229)
We are getting the token using LTIAuthenticationTokenService.authenticate() and we re-use it for multiple, consecutive web-service calls. For this reason, we cache the token for 2 minutes, which until now had worked on all our other customer's servers.
Is there a DOME variable or configuration setting that controls how long the authentication token is valid?
There are DOME configuration variables that control the lifetime of access tokens, and I believe that these apply to D2LWS tokens. If these calls were working with your back-end service before, and are not now, then this may be exposing either a mis-configuration of your LMS, or a regression defect introduced with a service pack to your service. In either case, your best bet is to contact D2L's support desk through either your organization's approved support contact, or your account or partner manager -- many of the DOME configuration variables are only modifiable by D2L themselves, and they can more likely assist your particular case to help determine if this is a mis-configuration or a defect.
D2L LMS DOME variables d2l.Security.WebService.MaxUsageCount and d2l.Security.WebService.TokenLifetime (seconds) control this behaviour