If an invalid key name (e.g. "a..b") in a primaries list in named.conf
is specified the wrong size is passed to isc_mem_put resulting in the
returned memory being put on the wrong freed list.
*** CID 316784: Incorrect expression (SIZEOF_MISMATCH)
/bin/named/config.c: 636 in named_config_getname()
630 isc_buffer_constinit(&b, objstr, strlen(objstr));
631 isc_buffer_add(&b, strlen(objstr));
632 dns_fixedname_init(&fname);
633 result = dns_name_fromtext(dns_fixedname_name(&fname), &b, dns_rootname,
634 0, NULL);
635 if (result != ISC_R_SUCCESS) {
CID 316784: Incorrect expression (SIZEOF_MISMATCH)
Passing argument "*namep" of type "dns_name_t *" and argument "8UL /* sizeof (*namep) */" to function "isc__mem_put" is suspicious.
636 isc_mem_put(mctx, *namep, sizeof(*namep));
637 *namep = NULL;
638 return (result);
639 }
640 dns_name_dup(dns_fixedname_name(&fname), mctx, *namep);
641
This commit adds stub parser support and tests for:
- an "http" global option for HTTP/2 endpoint configuration.
- command line options to set http or https port numbers by
specifying -p http=PORT or -p https=PORT. (NOTE: this change
only affects syntax; specifying HTTP and HTTPS ports on the
command line currently has no effect.)
- named.conf options "http-port" and "https-port"
- HTTPSPORT environment variable for use when running tests.
Add support for a "tls" key/value pair for zone primaries, referencing
either a "tls" configuration statement or "ephemeral". If set to use
TLS, zones will send SOA and AXFR/IXFR queries over a TLS channel.
The general logic behind the addition of this new feature works as
folows:
When a client query arrives, the basic path (query.c / ns_query_recurse)
was to create a fetch, waiting for completion in fetch_callback.
With the introduction of stale-answer-client-timeout, a new event of
type DNS_EVENT_TRYSTALE may invoke fetch_callback, whenever stale
answers are enabled and the fetch took longer than
stale-answer-client-timeout to complete.
When an event of type DNS_EVENT_TRYSTALE triggers fetch_callback, we
must ensure that the folowing happens:
1. Setup a new query context with the sole purpose of looking up for
stale RRset only data, for that matters a new flag was added
'DNS_DBFIND_STALEONLY' used in database lookups.
. If a stale RRset is found, mark the original client query as
answered (with a new query attribute named NS_QUERYATTR_ANSWERED),
so when the fetch completion event is received later, we avoid
answering the client twice.
. If a stale RRset is not found, cleanup and wait for the normal
fetch completion event.
2. In ns_query_done, we must change this part:
/*
* If we're recursing then just return; the query will
* resume when recursion ends.
*/
if (RECURSING(qctx->client)) {
return (qctx->result);
}
To this:
if (RECURSING(qctx->client) && !QUERY_STALEONLY(qctx->client)) {
return (qctx->result);
}
Otherwise we would not proceed to answer the client if it happened
that a stale answer was found when looking up for stale only data.
When an event of type DNS_EVENT_FETCHDONE triggers fetch_callback, we
proceed as before, resuming query, updating stats, etc, but a few
exceptions had to be added, most important of which are two:
1. Before answering the client (ns_client_send), check if the query
wasn't already answered before.
2. Before detaching a client, e.g.
isc_nmhandle_detach(&client->reqhandle), ensure that this is the
fetch completion event, and not the one triggered due to
stale-answer-client-timeout, so a correct call would be:
if (!QUERY_STALEONLY(client)) {
isc_nmhandle_detach(&client->reqhandle);
}
Other than these notes, comments were added in code in attempt to make
these updates easier to follow.
These options were ancient or made obsolete a long time ago, it is
safe to remove them.
Also stop printing ancient options, they should be treated the same as
unknown options.
Removed options: lwres, geoip-use-ecs, sit-secret, use-ixfr,
acache-cleaning-interval, acache-enable, additional-from-auth,
additional-from-cache, allow-v6-synthesis, dnssec-enable,
max-acache-size, nosit-udp-size, queryport-pool-ports,
queryport-pool-updateinterval, request-sit, use-queryport-pool, and
support-ixfr.
The DNS Flag Day 2020 reduced all the EDNS buffer sizes to 1232. In
this commit, we revert the default value for nocookie-udp-size back to
4096 because the option is too obscure and most people don't realize
that they also need to change this configuration option in addition to
max-udp-size.
Since the queries sent towards root and TLD servers are now included in
the count (as a result of the fix for CVE-2020-8616),
"max-recursion-queries" has a higher chance of being exceeded by
non-attack queries. Increase its default value from 75 to 100.
Before this update, BIND would attempt to do a full recursive resolution
process for each query received if the requested rrset had its ttl
expired. If the resolution fails for any reason, only then BIND would
check for stale rrset in cache (if 'stale-cache-enable' and
'stale-answer-enable' is on).
The problem with this approach is that if an authoritative server is
unreachable or is failing to respond, it is very unlikely that the
problem will be fixed in the next seconds.
A better approach to improve performance in those cases, is to mark the
moment in which a resolution failed, and if new queries arrive for that
same rrset, try to respond directly from the stale cache, and do that
for a window of time configured via 'stale-refresh-time'.
Only when this interval expires we then try to do a normal refresh of
the rrset.
The logic behind this commit is as following:
- In query.c / query_gotanswer(), if the test of 'result' variable falls
to the default case, an error is assumed to have happened, and a call
to 'query_usestale()' is made to check if serving of stale rrset is
enabled in configuration.
- If serving of stale answers is enabled, a flag will be turned on in
the query context to look for stale records:
query.c:6839
qctx->client->query.dboptions |= DNS_DBFIND_STALEOK;
- A call to query_lookup() will be made again, inside it a call to
'dns_db_findext()' is made, which in turn will invoke rbdb.c /
cache_find().
- In rbtdb.c / cache_find() the important bits of this change is the
call to 'check_stale_header()', which is a function that yields true
if we should skip the stale entry, or false if we should consider it.
- In check_stale_header() we now check if the DNS_DBFIND_STALEOK option
is set, if that is the case we know that this new search for stale
records was made due to a failure in a normal resolution, so we keep
track of the time in which the failured occured in rbtdb.c:4559:
header->last_refresh_fail_ts = search->now;
- In check_stale_header(), if DNS_DBFIND_STALEOK is not set, then we
know this is a normal lookup, if the record is stale and the query
time is between last failure time + stale-refresh-time window, then
we return false so cache_find() knows it can consider this stale
rrset entry to return as a response.
The last additions are two new methods to the database interface:
- setservestale_refresh
- getservestale_refresh
Those were added so rbtdb can be aware of the value set in configuration
option, since in that level we have no access to the view object.
This commit adds couple of additional safeguards against running
sends/reads on inactive sockets. The changes was modeled after the
changes we made to netmgr/tcpdns.c
Parse the configuration of tls objects into SSL_CTX* objects. Listen on
DoT if 'tls' option is setup in listen-on directive. Use DoT/DoH ports
for DoT/DoH.
The DNS Flag Day 2020 aims to remove the IP fragmentation problem from
the UDP DNS communication. In this commit, we implement the required
changes and simplify the logic for picking the EDNS Buffer Size.
1. The defaults for `edns-udp-size`, `max-udp-size` and
`nocookie-udp-size` have been changed to `1232` (the value picked by
DNS Flag Day 2020).
2. The probing heuristics that would try 512->4096->1432->1232 buffer
sizes has been removed and the resolver will always use just the
`edns-udp-size` value.
3. Instead of just disabling the PMTUD mechanism on the UDP sockets, we
now set IP_DONTFRAG (IPV6_DONTFRAG) flag. That means that the UDP
packets won't get ever fragmented. If the ICMP packets are lost the
UDP will just timeout and eventually be retried over TCP.
The current serve-stale implementation in BIND 9 stores all received
records in the cache for a max-stale-ttl interval (default 12 hours).
This allows DNS operators to turn the serve-stale answers in an event of
large authoritative DNS outage. The caching of the stale answers needs
to be enabled before the outage happens or the feature would be
otherwise useless.
The negative consequence of the default setting is the inevitable
cache-bloat that happens for every and each DNS operator running named.
In this MR, a new configuration option `stale-cache-enable` is
introduced that allows the operators to selectively enable or disable
the serve-stale feature of BIND 9 based on their decision.
The newly introduced option has been disabled by default,
e.g. serve-stale is disabled in the default configuration and has to be
enabled if required.
it is now an error to have two primaries lists with the same
name. this is true regardless of whether the "primaries" or
"masters" keywords were used to define them.
as "type primary" is preferred over "type master" now, it makes
sense to make "primaries" available as a synonym too.
added a correctness check to ensure "primaries" and "masters"
cannot both be used in the same zone.
Originally, the default value for max-stale-ttl was 1 week, which could
and in some scenarios lead to cache exhaustion on a busy resolvers.
Picking the default value will always be juggling between value that's
useful (e.g. keeping the already cached records after they have already
expired and the upstream name servers are down) and not bloating the
cache too much (e.g. keeping everything for a very long time). The new
default reflects what we think is a reasonable to time to react on both
sides (upstream authoritative and downstream recursive).
this corrects some style glitches such as:
```
long_function_call(arg, arg2, arg3, arg4, arg5, "str"
"ing");
```
...by adjusting the penalties for breaking strings and call
parameter lists.
Both clang-tidy and uncrustify chokes on statement like this:
for (...)
if (...)
break;
This commit uses a very simple semantic patch (below) to add braces around such
statements.
Semantic patch used:
@@
statement S;
expression E;
@@
while (...)
- if (E) S
+ { if (E) { S } }
@@
statement S;
expression E;
@@
for (...;...;...)
- if (E) S
+ { if (E) { S } }
@@
statement S;
expression E;
@@
if (...)
- if (E) S
+ { if (E) { S } }
'dnssec-policy' can now also be set on the options and view level and
a zone that does not set 'dnssec-policy' explicitly will inherit it
from the view or options level.
This requires a new keyword to be introduced: 'none'. If set to
'none' the zone will not be DNSSEC maintained, in other words it will
stay unsigned. You can use this to break the inheritance. Of course
you can also break the inheritance by referring to a different
policy.
The keywords 'default' and 'none' are not allowed when configuring
your own dnssec-policy statement.
Add appropriate tests for checking the configuration (checkconf)
and add tests to the kasp system test to verify the inheritance
works.
Edit the kasp system test such that it can deal with unsigned zones
and views (so setting a TSIG on the query).
It was found that NSEC Aggressive Caching has a significant performance impact
on BIND 9 when used as recursor. This commit disables the synth-from-dnssec
configuration option by default to provide immediate remedy for people running
BIND 9.12+. The NSEC Aggressive Cache will be enabled again after a proper fix
will be prepared.
This commit changes the BIND cookie algorithms to match
draft-sury-toorop-dnsop-server-cookies-00. Namely, it changes the Client Cookie
algorithm to use SipHash 2-4, adds the new Server Cookie algorithm using SipHash
2-4, and changes the default for the Server Cookie algorithm to be siphash24.
Add siphash24 cookie algorithm, and make it keep legacy aes as
- "--with-geoip" is used to enable the legacy GeoIP library.
- "--with-geoip2" is used to enable the new GeoIP2 library
(libmaxminddb), and is on by default if the library is found.
- using both "--with-geoip" and "--with-geoip2" at the same time
is an error.
- an attempt is made to determine the default GeoIP2 database path at
compile time if pkg-config is able to report the module prefix. if
this fails, it will be necessary to set the path in named.conf with
geoip-directory
- Makefiles have been updated, and a stub lib/dns/geoip2.c has been
added for the eventual GeoIP2 search implementation.
- managed-keys is now deprecated as well as trusted-keys, though
it continues to work as a synonym for dnssec-keys
- references to managed-keys have been updated throughout the code.
- tests have been updated to use dnssec-keys format
- also the trusted-keys entries have been removed from the generated
bind.keys.h file and are no longer generated by bindkeys.pl.
Since 2008, the cleaning-interval timer has been documented as
"effectively obsolete" and disabled in the default configuration with
a comment saying "now meaningless".
This change deletes all the code that implements the cleaning-interval
timer, except for the config parser in whcih it is now explicitly
marked as obsolete.
I have verified (using the deletelru and deletettl cache stats) that
named still cleans the cache after this change.
- make some cfg-parsing functions global so they can be run
from filter-aaaa.so
- add filter-aaaa options to the hook module's parser
- mark filter-aaaa options in named.conf as obsolete, remove
from named and checkconf, and update the filter-aaaa test not to
use checkconf anymore
- remove filter-aaaa-related struct members from dns_view
Sometimes it is useful to set a 'floor' on the TTL for records
to be cached. Some sites like to use ridiculously low TTLs for
some reason, and that often is not compatible with slow links.
Signed-off-by: Michael Milligan <milli@acmeps.com>
Signed-off-by: LaMont Jones <lamont@debian.org>
To minimize the effort required to set up IANA root zone mirroring,
define a default master server list for the root zone and use it when
that zone is to be mirrored and no master server list was explicitly
specified. Contents of that list are taken from RFC 7706 and are
subject to change in future releases.
Since the static get_masters_def() function in bin/named/config.c does
exactly what named_zone_configure() in bin/named/zoneconf.c needs to do,
make the former non-static and use it in the latter to prevent code
duplication.
Rather than overloading dns_zone_slave and discerning between a slave
zone and a mirror zone using a zone option, define a separate enum
value, dns_zone_mirror, to be used exclusively by mirror zones. Update
code handling slave zones to ensure it also handles mirror zones where
applicable.
