Ticket History #8358: Report inquire_attrs_for_mech mech failures

As committed, this change breaks SPNEGO and gss_acquire_cred() in the
presence of mechs which don't implement RFC 5587. I have removed the
pullup tag until we commit a better change.

Report inquire_attrs_for_mech mech failures

Previously, gss_inquire_attrs_for_mech() would return a list of mech
attributes that it knew about when given a bad mech oid or a mechanism
which did not provide a gss_inquire_attrs_for_mech() method. It seems
more useful to just report the failure to the application rather than
allowing it to continue with a faulty mechanism.

(cherry picked from commit 030a4a03a0480969d6acf1591f39fd194642805a)

https://github.com/krb5/krb5/commit/96125088fc6cf56dd839004dc6f6ef202de9da7e
Author: Robbie Harwood <rharwood@redhat.com>
Committer: Tom Yu <tlyu@mit.edu>
Commit: 96125088fc6cf56dd839004dc6f6ef202de9da7e
Branch: krb5-1.14
src/lib/gssapi/mechglue/g_mechattr.c | 19 ++++++++++---------
1 files changed, 10 insertions(+), 9 deletions(-)

Revisit inquire_attrs_for_mech on old mechs

In gss_inquire_attrs_for_mech(), if the mech does not implement RFC
5587, return success with empty mech_attrs and known_mech_attrs sets
to indicate a lack of knowledge for all attributes. The previous
behavior of returning an error caused gss_indicate_mechs_by_attr() to
fail out in the presence of an old mechanism, in turn causing
gss_acquire_cred() and SPNEGO to break.

(cherry picked from commit 89683d1f135765e91041f3a239af865b11aaf86b)

https://github.com/krb5/krb5/commit/9e26436f2acb5fcd450f5cc1ac1f81ccbb0aa6ac
Author: Greg Hudson <ghudson@mit.edu>
Committer: Tom Yu <tlyu@mit.edu>
Commit: 9e26436f2acb5fcd450f5cc1ac1f81ccbb0aa6ac
Branch: krb5-1.14
src/lib/gssapi/mechglue/g_mechattr.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)