When query processing hits a delegation from a locally configured zone,
an attempt may be made to look for a better answer in the cache. In
such a case, the zone-sourced delegation data is set aside and the
lookup is retried using the cache database. When that lookup is
completed, a decision is made whether the answer found in the cache is
better than the answer found in the zone.
Currently, if the zone-sourced answer turns out to be better than the
one found in the cache:
- qctx->zdb is not restored into qctx->db,
- qctx->node, holding the zone database node found, is not even saved.
Thus, in such a case both qctx->db and qctx->node will point at cache
data. This is not an issue for BIND versions which do not support
mirror zones because in these versions non-recursive queries always
cause the zone-sourced delegation to be returned and thus the
non-recursive part of query_delegation() is never reached if the
delegation is coming from a zone. With mirror zones, however,
non-recursive queries may cause cache lookups even after a zone
delegation is found. Leaving qctx->db assigned to the cache database
when query_delegation() determines that the zone-sourced delegation is
the best answer to the client's query prevents DS records from being
added to delegations coming from mirror zones. Fix this issue by
keeping the zone database and zone node in qctx while the cache is
searched for an answer and then restoring them into qctx->db and
qctx->node, respectively, if the zone-sourced delegation turns out to be
the best answer. Since this change means that qctx->zdb cannot be used
as the glue database any more as it will be reset to NULL by RESTORE(),
ensure that qctx->db is not a cache database before attaching it to
qctx->client->query.gluedb.
Furthermore, current code contains a conditional statement which
prevents a mirror zone from being used as a source of glue records.
Said statement was added to prevent assertion failures caused by
attempting to use a zone database's glue cache for finding glue for an
NS RRset coming from a cache database. However, that check is overly
strict since it completely prevents glue from being added to delegations
coming from mirror zones. With the changes described above in place,
the scenario this check was preventing can no longer happen, so remove
the aforementioned check.
If qctx->zdb is not NULL, qctx->zfname will also not be NULL;
qctx->zsigrdataset may be NULL in such a case, but query_putrdataset()
handles pointers to NULL pointers gracefully. Remove redundant
conditional expressions to make the cleanup code in query_freedata()
match the corresponding sequences of SAVE() / RESTORE() macros more
closely.
- mark the 'geoip-use-ecs' option obsolete; warn when it is used
in named.conf
- prohibit 'ecs' ACL tags in named.conf; note that this is a fatal error
since simply ignoring the tags could make ACLs behave unpredictably
- re-simplify the radix and iptable code
- clean up dns_acl_match(), dns_aclelement_match(), dns_acl_allowed()
and dns_geoip_match() so they no longer take ecs options
- remove the ECS-specific unit and system test cases
- remove references to ECS from the ARM
Interrupt query processing when query_recurse() attempts to ask the same
name servers for the same QNAME/QTYPE tuple for two times in a row as
this indicates that query processing may be stuck for an indeterminate
period of time, e.g. due to interactions between features able to
restart query_lookup().
The three functions has been modeled after the arc4random family of
functions, and they will always return random bytes.
The isc_random family of functions internally use these CSPRNG (if available):
1. getrandom() libc call (might be available on Linux and Solaris)
2. SYS_getrandom syscall (might be available on Linux, detected at runtime)
3. arc4random(), arc4random_buf() and arc4random_uniform() (available on BSDs and Mac OS X)
4. crypto library function:
4a. RAND_bytes in case OpenSSL
4b. pkcs_C_GenerateRandom() in case PKCS#11 library
4762. [func] "update-policy local" is now restricted to updates
from local addresses. (Previously, other addresses
were allowed so long as updates were signed by the
local session key.) [RT #45492]
4724. [func] By default, BIND now uses the random number
functions provided by the crypto library (i.e.,
OpenSSL or a PKCS#11 provider) as a source of
randomness rather than /dev/random. This is
suitable for virtual machine environments
which have limited entropy pools and lack
hardware random number generators.
This can be overridden by specifying another
entropy source via the "random-device" option
in named.conf, or via the -r command line option;
however, for functions requiring full cryptographic
strength, such as DNSSEC key generation, this
cannot be overridden. In particular, the -r
command line option no longer has any effect on
dnssec-keygen.
This can be disabled by building with
"configure --disable-crypto-rand".
[RT #31459] [RT #46047]
4708. [cleanup] Legacy Windows builds (i.e. for XP and earlier)
are no longer supported. [RT #45186]
4707. [func] The lightweight resolver daemon and library (lwresd
and liblwres) have been removed. [RT #45186]
4706. [func] Code implementing name server query processing has
been moved from bin/named to a new library "libns".
Functions remaining in bin/named are now prefixed
with "named_" rather than "ns_". This will make it
easier to write unit tests for name server code, or
link name server functionality into new tools.
[RT #45186]
