Since the "tkey-gssapi-credential" statement has been previously
deprecated, mark it as ancient and remove all code related to it:
- The code processing the "tkey-gssapi-credential" statement in the
configuration is the only user of the dst_gssapi_acquirecred() and
dst_gssapi_releasecred() functions, so remove them along with their
static helper functions and a backup definition of the
GSS_KRB5_MECHANISM macro.
- When calling gss_accept_sec_context(), pass GSS_C_NO_CREDENTIAL
instead of the credential acquired by gss_acquire_cred().
(Previously, NULL was passed when "tkey-gssapi-credential" was not
specified. Kerberos headers define GSS_C_NO_CREDENTIAL as
(gss_cred_id_t) 0, so the logic was effectively the same, but using
the GSS_C_NO_CREDENTIAL macro is more appropriate.) This renders
the 'cred' parameter for dst_gssapi_acceptctx() redundant, so remove
it from the prototype of the latter. (Contrary to what the
documentation for dst_gssapi_acceptctx() claims,
dst_gssapi_releasecred() does not need to subsequently be called to
free the GSS-API context; a dst_gssapi_deletectx() call in
gssapi_destroy() takes care of that when the dynamically generated
TSIG key is destroyed.)
- Remove the 'gsscred' member from struct dns_tkeyctx, along with its
related dns_gss_cred_id_t typedef.
Update the relevant sections of the ARM and code comments accordingly.
This makes the "tkey-gssapi-keytab" statement the only way to set up
GSS-TSIG in named.
Remove redundant code from bin/named/tkeyconf.c while at it.
Two inconsequential bug fixes are not release note worthy.
Use more user-centric terminology about dnssec-policy manual-mode.
Add links, shorten notes.
Keeping the Known Issues as part of the rendered docs has the issue that
the list can't be updated on the official docs website until the next
release. This is unpractical is a high-priority issue is discovered
shortly after a release. Keep the Known Issues in wiki and simply link
to the list from the rendered docs. The wiki article can be updated at
any time as needed.