Evaluation part 1 of JDK-6722928: Provide a default native GSS-API library on Windows

Wed Apr 1 16:21:45 UTC 2020

Hi Max,

at last I took some time to evaluate you SSPI bridge. This is part one. 
Interaction evaluation will follow in a second email.

Assumptions:
* All methods, objects behave the same as with JGSS
* AcceptSecurityContext is not implemented so should everything 
associated with it fail (GSSException)
* Code analysis happens based on 
https://github.com/AdoptOpenJDK/openjdk-jdk13u/blob/master/src/java.security.jgss/windows/native/libsspi_bridge/sspi.cpp
and zulu13.29.9-ca-jdk13.0.2-win_x64

Findings C:
* sspi.cpp: Would it make sense to replace "__declspec(dllexport)" with 
JNIEXPORT?
* GSSManager#createCredential(): I'd expect an exception when *not* 
GSSCredential.INITIATE_ONLY is requested/passed
* sspi.cpp#L67-L68: Feels a bit awkward to permit SSPI_BRIDGE_TRACE="". 
Why not have "if (trace && *trace)"?
* sspi.cpp#L233: The function name says "show_oid", but I see no OID 
printed. Simply symbolic names.
* sspi.cpp#L290: Empty string check? like (realm && *realm)
* Usage of %p: If you don't know that %p is used it is hard to tell why 
this output is there. May turn to "at 0x%p" in general?
* sspi.cpp#L359: -2!= reads awkward. Reformat?
* sspi.cpp#L482-L483: This is highly questionable. While it is true for 
Windows, it does not stick to gss_compare_name behavior. Don't know what 
the correct approach would be here.
* sspi.cpp#L595: That's weird. A string leads to a length? Should it 
read: PP("Name found: %ls -> %s [%d]", names, buffer, len)
* sspi.cpp#L618: You are resetting cred_usage passed with the function. 
This looks like a bug to me.
* sspi.cpp#L619: Reads very bad, maybe turn into 
"PP("AcquireCredentialsHandle with usage: %d, creds: 0x%p", cred_usage, 
desired_mechs)"
* sspi.cpp#L627-L633: Trace message could be more expressive, e.g., 
"Requesting Kerberos mech"
* sspi.cpp#L657-L658 and sspi.cpp#L687-L688: They look wrong and do not 
correspond to GSSCredentialImpl.java#L628-L640. default value should be 
INITIATE_AND_ACCEPT.
   Same as in GSS-API:
$ sudo python3
 > Python 3.7.7 (default, Mar 19 2020, 21:26:00)
 > [Clang 9.0.1 (git at github.com:llvm/llvm-project.git 
c1a0a213378a458fbea1a5c77b31 on freebsd12
 > Type "help", "copyright", "credits" or "license" for more information.
 > >>> import gssapi
 > >>> cred = gssapi.Credentials(usage='nonsense')
 > >>> cred.usage
 > 'both'
This also may be a bug in py-gssapi/MIT Kerberos
* sspi.cpp#L149
** Can you apply a better output like ISO 8601? In strftime(3) that 
would be "%FT%T, ..."
** "%uld" does not seem to work here: 4294967295ld. Shouldn't that read 
"%"PRIu32" seconds" or "%lu seconds"?
* sspi.cpp#L744: "Comparison result: %d". You are not comparing the 
result, but print comparsion result.
* sspi.cpp#L841: man 3 gss_import_sec_context says: GSS_S_UNAVAILABLE
* sspi.cpp#L977-L979: Not helpful when the SEC_E_* not mapped to 
major/minor. This likely applies to most mapping functions.
* sspi.cpp#L1012: Maybe: "Names: client: %s, server: %s"?
* sspi.cpp#L1046: Maybe like gss_export_sec_context?
* sspi.cpp#L1169: Remove word "IMPLEMENTED"
* sspi.cpp#L1169: Maybe like gss_export_sec_context?
* sspi.cpp#L1480: Includes a trailing, redundant newline
* sspi.cpp#L729-L748: Why do you do this? The documentation for 
parameter 1 says: If the process that requests the handle does not have 
access to the credentials, the function returns an error. I have 
verified this with py-win32: win32security.AcquireCredentialsHandle(). 
Infact, it accepts any principal and always returns the default one. I 
found these:
** https://github.com/twosigma/gsskrb5/blob/master/krb5/krb5cred.c#L127-L132
** https://github.com/twosigma/gsskrb5/blob/master/krb5/krb5cred.c#L127-L132
 > >>> cred, time = 
win32security.AcquireCredentialsHandle("Administrator at ORACLE.COM", 
"Kerberos", win32security.SECPKG_CRED_OUTBOUND, None, None)
 > >>> cred.QueryCredentialsAttributes(1)
 > 'osipovmi at AD001.SIEMENS.NET'

Findings Java:
* GssManager#createCredential() with ACCEPT_ONLY or INITIATE_AND_ACCEPT 
gives me weird credentials with partial null nembers. I'd expect an 
exception here.
* This is one fails, but shall work:
 > GSSManager manager = GSSManager.getInstance();
 > GSSName userName = manager.createName("osipovmi", GSSName.NT_USER_NAME);
 > GSSCredential cred = manager.createCredential(userName, 
GSSCredential.DEFAULT_LIFETIME, krb5Oid, GSSCredential.INITIATE_ONLY);
 > [SSPI:1627] >>>> Calling gss_create_empty_oid_set...
 > [SSPI:1542] >>>> Calling gss_add_oid_set_member...
 > [SSPI:612] >>>> Calling gss_acquire_cred...
 > [SSPI:619] AcquireCredentialsHandle with 0 00000257FFB199B0
 > [SSPI:262] gss_OID_set.count is 1
 > [SSPI:237] Kerberos mech
 > [SSPI:628] reqKerberos
 > [SSPI:152] cred expiration: 09/13/30828  04:48 4294967295ld
 > [SSPI:732] Acquiring cred with a name. Check if it's me.
 > [SSPI:791] >>>> Calling gss_inquire_cred...
 > [SSPI:811] Allocate new name at 00000257FFB2BC40
 > [SSPI:428] >>>> Calling gss_compare_name...
 > [SSPI:437] Comparing osipovmi at AD001.SIEMENS.NET and osipovmi
 > [SSPI:325] >>>> Calling gss_release_name 00000257FFB17830...
 > [SSPI:744] Comparing result: 0
 > [SSPI:767] >>>> Calling gss_release_cred...
 > [SSPI:1641] >>>> Calling gss_release_oid_set...
 > Exception in thread "main" GSSException: Failure unspecified at 
GSS-API level
 > 	at 
java.security.jgss/sun.security.jgss.wrapper.GSSLibStub.acquireCred(Native 
Method)

The problem is that I provide a local name and expect the default realm 
to be used. It seems like #createCredential() does not take that into 
account. It also has no avail when the canonicalized form is used. See 
sspi.cpp#L729-L748.
* GssManager#createContext(GSSCredential) still works although this 
should be a acceptor context. I expect an expception. Does not fail with 
JGSS either. MIT Kerberos with py-gssapi properly fails:
 > >>> cred = gssapi.Credentials(usage='accept') 
                                   >>> cred
 > <gssapi.creds.Credentials object at 0x80164bbb0>
 > >>> context = gssapi.SecurityContext(usage='initiate', creds=cred, 
name=canon_name, mech=gssapi.MechType.kerberos)
 > >>> context.step(None)
 > Traceback (most recent call last):
 >   File "<stdin>", line 1, in <module>
 >   File "<decorator-gen-15>", line 2, in step
 >   File "/usr/local/lib/python3.7/site-packages/gssapi/_utils.py", 
line 167, in check_last_err
 >     return func(self, *args, **kwargs)
 >   File "<decorator-gen-5>", line 2, in step
 >   File "/usr/local/lib/python3.7/site-packages/gssapi/_utils.py", 
line 127, in catch_and_return_token
 >     return func(self, *args, **kwargs)
 >   File 
"/usr/local/lib/python3.7/site-packages/gssapi/sec_contexts.py", line 
521, in step
 >     return self._initiator_step(token=token)
 >   File 
"/usr/local/lib/python3.7/site-packages/gssapi/sec_contexts.py", line 
542, in _initiator_step
 >     token)
 >   File "gssapi/raw/sec_contexts.pyx", line 245, in 
gssapi.raw.sec_contexts.init_sec_context
 > gssapi.raw.exceptions.MissingCredentialsError: Major (458752): Es 
wurden keine Anmeldedaten übergeben oder die Anmeldedaten waren nicht 
verfügbar bzw. ein Zugriff darauf nicht möglich., Minor (100001): 
Unknown code 0

That's it for now.

Michael