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

Wed Apr 15 21:17:09 UTC 2020

Max,

did you get a chance to go through the comments? I'd like to start 
review 2 (interaction) somewhere next week, but would like to sort this 
one out first.

Michael

Am 2020-04-02 um 03:47 schrieb Weijun Wang:
> I'll read this carefully, thanks a lot for the comments.
> 
> --Max
> 
>> On Apr 2, 2020, at 12:21 AM, Osipov, Michael <michael.osipov at siemens.com> wrote:
>>
>> 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
> 