On Apr 2, 2020, at 12:21 AM, Osipov, Michael <michael.osi...@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 (g...@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("administra...@oracle.com",
"Kerberos", win32security.SECPKG_CRED_OUTBOUND, None, None)
cred.QueryCredentialsAttributes(1)
'osipo...@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 osipo...@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
