Older databases may lack explicitly stored salts where the salt is the default
one. When fetching a client entry for an AS-REQ, add default salts to keys that
lack one.
Whilst Windows does not canonicalize enterprise principal names if the
canonicalize flag is unset, the original specification in
draft-ietf-krb-wg-kerberos-referrals-03.txt says we should. Non-Windows
deployments of Heimdals are unlikely to understand enterprise principal names
in tickets, and are also unlikely to set the canonicalize flag, so this makes
sense. (It was also the behavior prior to moving the name canonicalization
logic into the KDC.)
This reverts commit 1b7e196e66.
It turns out that, contrary to the referrals draft, Windows does not
canonicalize enterprise principal names if the canonicalize KDC option is
unset.
Enterprise principal client names in AS-REQs should always be canonicalized
irrespective of the setting the canonicalize KDC option. Perform this check in
the KDC rather than HDB.
Do not set the HDB_F_GET_KRBTGT flag unless the client actually requested a TGS
principal.
Mirroring the logic recently introduced in the TGS, this patch modifies the KDC
to perform client and server canonicalization itself rather than relying on the
backend to do so. Per RFC 6806, the behavior is slightly different for the AS
in that the setting of the canonicalize flag in the AS-REQ does impact the
returned names in the ticket. In order to support realm canonicalization or
other custom behavior, we allow the backend to force the KDC to canonicalize by
setting the force-canonicalize flag in the returned client or server entries.
e11abf41 added support in libhdb for always dereferencing principal aliases
during an AS-REQ (where dereferencing refers to enabling alias lookups, and
rewriting the returned entry with the alias name unless canonicalization was
enabled).
Due to the KDC setting HDB_F_FOR_AS_REQ for all lookups from the AS, this
allowed aliases on the TGS itself to be dereferenced during an AS-REQ; however,
on presenting the TGT, the TGS would fail to resolve. Creating an explicit TGS
principal for the aliased realm would work (at least prior to c555ed6a), but
this could be confusing to deploy.
This commit changes enables alias dereferencing when HDB_F_GET_ANY is set,
which essentially means dereference whenever the request is coming from the KDC
(as opposed to, say, kadmin).
We also backout c555ed6a, which changed the TGS to always canonicalize the
server realm, as this breaks serving multiple realms from a single KDC, where
server principals in different realms share a single canonical entry.
HDB_F_CANON is now passed to the backend as a hint only, and per RFC 6806 the
principal name is never changed in TGS replies. (However, for Samba interop,
backends can override this by setting the force-canonicalize HDB flag.)
Adds support for "hard" aliases when initially authenticating, that is,
allowing a client or server principal to be known by many names without
requiring that the client support name canonicalization.
In order to avoid changing the behavior for other backends such as Samba, this
is implemented in the HDB backend rather than the KDC.
To use, add an alias for both the client and TGS ("krbtgt") principals using
kadmin. This behavior is unchanged if name canonicalization is enabled.
We used to update the iprop log and HDB in different orders depending on
the kadm5 operation, which then led to various race conditions.
The iprop log now functions as a two-phase commit (with roll forward)
log for HDB changes. The log is auto-truncated, keeping the latest
entries that fit in a configurable maximum number of bytes (defaults to
50MB). See the log-max-size parameter description in krb5.conf(5).
The iprop log format and the protocol remain backwards-compatible with
earlier versions of Heimdal. This is NOT a flag-day; there is NO need
to update all the slaves at once with the master, though it is advisable
in general. Rolling upgrades and downgrades should work.
The sequence of updates is now (with HDB and log open and locked):
a) check that the HDB operation will succeed if attempted,
b) append to iprop log and fsync() it,
c) write to HDB (which should fsync()),
d) mark last log record committed (no fsync in this case).
Every kadm5 write operation recover transactions not yet confirmed as
committed, thus there can be at most one unconfirmed commit on a master
KDC.
Reads via kadm5_get_principal() also attempt to lock the log, and if
successful, recover unconfirmed transactions; readers must have write
access and must win any race to lock the iprop log.
The ipropd-master daemon also attempts to recover unconfirmed
transactions when idle.
The log now starts with a nop record whose payload records the offset of
the logical end of the log: the end of the last confirmed committed
transaction. This is kown as the "uber record". Its purpose is
two-fold: act as the confirmation of committed transactions, and provide
an O(1) method of finding the end of the log (i.e., without having to
traverse the entire log front to back).
Two-phase commit makes all kadm5 writes single-operation atomic
transactions (though some kadm5 operations, such as renames of
principals, and changes to principals' aliases, use multiple low-level
HDB write operations, but still all in one transaction). One can still
hold a lock on the HDB across many operations (e.g., by using the lock
command in a kadmin -l or calling kadm5_lock()) in order to push
multiple transactions in sequence, but this sequence will not be atomic
if the process or host crashes in the middle.
As before, HDB writes which do not go through the kadm5 API are excluded
from all of this, but there should be no such writes.
Lastly, the iprop-log(1) command is enhanced as follows:
- The dump, last-version, truncate, and replay sub-commands now have an
option to not lock the log. This is useful for inspecting a running
system's log file, especially on slave KDCs.
- The dump, last-version, truncate, and replay sub-commands now take an
optional iprop log file positional argument, so that they may be used
to inspect log files other than the running system's
configured/default log file.
Extensive code review and some re-writing for clarity by Viktor Dukhovni.
most of these warnings are not problems because of ample
use of abort() calls. However, the large number of warnings
makes it difficult to identify real problems. Initialize
the variables to shut up the compilers.
Change-Id: I8477c11b17c7b6a7d9074c721fdd2d7303b186a8
