Release notes¶
Knot Resolver 4.0.0 (2019-0m-dd)¶
Incompatible changes¶
see upgrading guide: https://knot-resolver.readthedocs.io/en/v4.0.0/upgrading.html#upgrade-from-3-to-4
configuration: trust_anchors aliases .file, .config() and .negative were removed (!788)
configuration: trust_anchors.keyfile_default is no longer accessible (!788)
daemon: -k/–keyfile and -K/–keyfile-ro options were removed
meson build system is now used for builds (!771)
build with embedded LMBD is no longer supported
default modules dir location has changed
DNSSEC is enabled by default
upstream packages for Debian now require systemd
libknot >= 2.8 is required
net.list() output format changed
Improvements¶
policy.TLS_FORWARD: if hostname is configured, send it on wire (!759)
hints module: allow configuring the TTL and change default from 0 to 5s
policy module: policy.rpz() will watch the file for changes by default
packaging: lua cqueues added to default dependencies where available
systemd: service is no longer auto-restarted on configuration errors
always send DO+CD flags upstream, even in insecure zones
Bugfixes¶
predict module: load stats module if config didn’t specify period (!755)
trust_anchors: don’t do 5011-style updates on anchors from files that were loaded as unmanaged trust anchors (!753)
trust_anchors.add(): include these TAs in .summary() (!753)
policy module: support ‘#’ for separating port numbers, for consistency
fix startup on macOS+BSD when </dev/null and cqueues installed
policy.RPZ: log problems from zone-file level of parser as well (#453)
fix flushing of messages to logs in some cases (!781)
fix fallback when SERVFAIL or REFUSED is received from upstream (!784)
fix crash when dealing with unknown TA key algorhitm (#449)
go insecure due to algorithm support even if DNSKEY is NODATA (!798)
Module API changes¶
kr_straddr_split() changed API a bit (compiler will catch that)
Knot Resolver 3.2.1 (2019-01-10)¶
Bugfixes¶
trust_anchors: respect validity time range during TA bootstrap (!748)
fix TLS rehandshake handling (!739)
make TLS_FORWARD compatible with GnuTLS 3.3 (!741)
special thanks to Grigorii Demidov for his long-term work on Knot Resolver!
Improvements¶
improve handling of timeouted outgoing TCP connections (!734)
trust_anchors: check syntax of public keys in DNSKEY RRs (!748)
validator: clarify message about bogus non-authoritative data (!735)
dnssec validation failures contain more verbose reasoning (!735)
new function trust_anchors.summary() describes state of DNSSEC TAs (!737), and logs new state of trust anchors after start up and automatic changes
trust anchors: refuse revoked DNSKEY even if specified explicitly, and downgrade missing the SEP bit to a warning
Knot Resolver 3.2.0 (2018-12-17)¶
New features¶
module edns_keepalive to implement server side of RFC 7828 (#408)
module nsid to implement server side of RFC 5001 (#289)
module bogus_log provides .frequent() table (!629, credit Ulrich Wisser)
module stats collects flags from answer messages (!629, credit Ulrich Wisser)
module view supports multiple rules with identical address/TSIG specification and keeps trying rules until a “non-chain” action is executed (!678)
module experimental_dot_auth implements an DNS-over-TLS to auth protocol (!711, credit Manu Bretelle)
net.bpf bindings allow advanced users to use eBPF socket filters
Bugfixes¶
http module: only run prometheus in parent process if using –forks=N, as the submodule collects metrics from all sub-processes as well.
TLS fixes for corner cases (!700, !714, !716, !721, !728)
fix build with -DNOVERBOSELOG (#424)
policy.{FORWARD,TLS_FORWARD,STUB}: respect net.ipv{4,6} setting (!710)
avoid SERVFAILs due to certain kind of NS dependency cycles, again (#374) this time seen as ‘circular dependency’ in verbose logs
policy and view modules do not overwrite result finished requests (!678)
Improvements¶
Dockerfile: rework, basing on Debian instead of Alpine
policy.{FORWARD,TLS_FORWARD,STUB}: give advantage to IPv6 when choosing whom to ask, just as for iteration
use pseudo-randomness from gnutls instead of internal ISAAC (#233)
tune the way we deal with non-responsive servers (!716, !723)
documentation clarifies interaction between policy and view modules (!678, !730)
Module API changes¶
new layer is added: answer_finalize
kr_request keeps ::qsource.packet beyond the begin layer
kr_request::qsource.tcp renamed to ::qsource.flags.tcp
kr_request::has_tls renamed to ::qsource.flags.tls
kr_zonecut_add(), kr_zonecut_del() and kr_nsrep_sort() changed parameters slightly
Knot Resolver 3.1.0 (2018-11-02)¶
Incompatible changes¶
hints.use_nodata(true) by default; that’s what most users want
libknot >= 2.7.2 is required
Improvements¶
cache: handle out-of-space SIGBUS slightly better (#197)
daemon: improve TCP timeout handling (!686)
Bugfixes¶
cache.clear(‘name’): fix some edge cases in API (#401)
fix error handling from TLS writes (!669)
avoid SERVFAILs due to certain kind of NS dependency cycles (#374)
Knot Resolver 3.0.0 (2018-08-20)¶
Incompatible changes¶
cache: fail lua operations if cache isn’t open yet (!639) By default cache is opened after reading the configuration, and older versions were silently ignoring cache operations. Valid configuration must open cache using cache.open() or cache.size = before executing cache operations like cache.clear().
libknot >= 2.7.1 is required, which brings also larger API changes
in case you wrote custom Lua modules, please consult https://knot-resolver.readthedocs.io/en/latest/lib.html#incompatible-changes-since-3-0-0
in case you wrote custom C modules, please see compile against Knot DNS 2.7 and adjust your module according to messages from C compiler
DNS cookie module (RFC 7873) is not available in this release, it will be later reworked to reflect development in IEFT dnsop working group
version module was permanently removed because it was not really used by users; if you want to receive notifications abou new releases please subscribe to https://lists.nic.cz/cgi-bin/mailman/listinfo/knot-resolver-announce
Bugfixes¶
fix multi-process race condition in trust anchor maintenance (!643)
ta_sentinel: also consider static trust anchors not managed via RFC 5011
Improvements¶
reorder_RR() implementation is brought back
bring in performace improvements provided by libknot 2.7
cache.clear() has a new, more powerful API
cache documentation was improved
old name “Knot DNS Resolver” is replaced by unambiguous “Knot Resolver” to prevent confusion with “Knot DNS” authoritative server
Knot Resolver 2.4.1 (2018-08-02)¶
Security¶
fix CVE-2018-10920: Improper input validation bug in DNS resolver component (security!7, security!9)
Bugfixes¶
cache: fix TTL overflow in packet due to min_ttl (#388, security!8)
TLS session resumption: avoid bad scheduling of rotation (#385)
HTTP module: fix a regression in 2.4.0 which broke custom certs (!632)
cache: NSEC3 negative cache even without NS record (#384) This fixes lower hit rate in NSEC3 zones (since 2.4.0).
minor TCP and TLS fixes (!623, !624, !626)
Knot Resolver 2.4.0 (2018-07-03)¶
Incompatible changes¶
minimal libknot version is now 2.6.7 to pull in latest fixes (#366)
Security¶
fix a rare case of zones incorrectly dowgraded to insecure status (!576)
New features¶
TLS session resumption (RFC 5077), both server and client (!585, #105) (disabled when compiling with gnutls < 3.5)
TLS_FORWARD policy uses system CA certificate store by default (!568)
aggressive caching for NSEC3 zones (!600)
optional protection from DNS Rebinding attack (module rebinding, !608)
module bogus_log to log DNSSEC bogus queries without verbose logging (!613)
Bugfixes¶
prefill: fix ability to read certificate bundle (!578)
avoid turning off qname minimization in some cases, e.g. co.uk. (#339)
fix validation of explicit wildcard queries (#274)
dns64 module: more properties from the RFC implemented (incl. bug #375)
Improvements¶
systemd: multiple enabled kresd instances can now be started using kresd.target
ta_sentinel: switch to version 14 of the RFC draft (!596)
support for glibc systems with a non-Linux kernel (!588)
support per-request variables for Lua modules (!533)
support custom HTTP endpoints for Lua modules (!527)
Knot Resolver 2.3.0 (2018-04-23)¶
Security¶
fix CVE-2018-1110: denial of service triggered by malformed DNS messages (!550, !558, security!2, security!4)
increase resilience against slow lorris attack (security!5)
New features¶
new policy.REFUSE to reply REFUSED to clients
Bugfixes¶
validation: fix SERVFAIL in case of CNAME to NXDOMAIN in a single zone (!538)
validation: fix SERVFAIL for DS . query (!544)
lib/resolve: don’t send unecessary queries to parent zone (!513)
iterate: fix validation for zones where parent and child share NS (!543)
TLS: improve error handling and documentation (!536, !555, !559)
Improvements¶
prefill: new module to periodically import root zone into cache (replacement for RFC 7706, !511)
network_listen_fd: always create end point for supervisor supplied file descriptor
use CPPFLAGS build environment variable if set (!547)
Knot Resolver 2.2.0 (2018-03-28)¶
New features¶
cache server unavailability to prevent flooding unreachable servers (Please note that caching algorithm needs further optimization and will change in further versions but we need to gather operational experience first.)
Bugfixes¶
don’t magically -D_FORTIFY_SOURCE=2 in some cases
allow large responses for outbound over TCP
fix crash with RR sets with over 255 records
Knot Resolver 2.1.1 (2018-02-23)¶
Bugfixes¶
when iterating, avoid unnecessary queries for NS in insecure parent. This problem worsened in 2.0.0. (#246)
prevent UDP packet leaks when using TLS forwarding
fix the hints module also on some other systems, e.g. Gentoo.
Knot Resolver 2.1.0 (2018-02-16)¶
Incompatible changes¶
stats: remove tracking of expiring records (predict uses another way)
systemd: re-use a single kresd.socket and kresd-tls.socket
ta_sentinel: implement protocol draft-ietf-dnsop-kskroll-sentinel-01 (our draft-ietf-dnsop-kskroll-sentinel-00 implementation had inverted logic)
libknot: require version 2.6.4 or newer to get bugfixes for DNS-over-TLS
Bugfixes¶
detect_time_jump module: don’t clear cache on suspend-resume (#284)
stats module: fix stats.list() returning nothing, regressed in 2.0.0
policy.TLS_FORWARD: refusal when configuring with multiple IPs (#306)
cache: fix broken refresh of insecure records that were about to expire
fix the hints module on some systems, e.g. Fedora (came back on 2.0.0)
build with older gnutls (conditionally disable features)
fix the predict module to work with insecure records & cleanup code
Knot Resolver 2.0.0 (2018-01-31)¶
Incompatible changes¶
systemd: change unit files to allow running multiple instances, deployments with single instance now must use kresd@1.service instead of kresd.service; see kresd.systemd(7) for details
systemd: the directory for cache is now /var/cache/knot-resolver
unify default directory and user to knot-resolver
directory with trust anchor file specified by -k option must be writeable
policy module is now loaded by default to enforce RFC 6761; see documentation for policy.PASS if you use locally-served DNS zones
drop support for alternative cache backends memcached, redis, and for Lua bindings for some specific cache operations
REORDER_RR option is not implemented (temporarily)
New features¶
aggressive caching of validated records (RFC 8198) for NSEC zones; thanks to ICANN for sponsoring this work.
forwarding over TLS, authenticated by SPKI pin or certificate. policy.TLS_FORWARD pipelines queries out-of-order over shared TLS connection Beware: Some resolvers do not support out-of-order query processing. TLS forwarding to such resolvers will lead to slower resolution or failures.
trust anchors: you may specify a read-only file via -K or –keyfile-ro
trust anchors: at build-time you may set KEYFILE_DEFAULT (read-only)
ta_sentinel module implements draft ietf-dnsop-kskroll-sentinel-00, enabled by default
serve_stale module is prototype, subject to change
extended API for Lua modules
Bugfixes¶
fix build on osx - regressed in 1.5.3 (different linker option name)
Knot Resolver 1.5.3 (2018-01-23)¶
Bugfixes¶
fix the hints module on some systems, e.g. Fedora. Symptom: undefined symbol: engine_hint_root_file
Knot Resolver 1.5.2 (2018-01-22)¶
Security¶
fix CVE-2018-1000002: insufficient DNSSEC validation, allowing attackers to deny existence of some data by forging packets. Some combinations pointed out in RFC 6840 sections 4.1 and 4.3 were not taken into account.
Bugfixes¶
memcached: fix fallout from module rename in 1.5.1
Knot Resolver 1.5.1 (2017-12-12)¶
Incompatible changes¶
script supervisor.py was removed, please migrate to a real process manager
module ketcd was renamed to etcd for consistency
module kmemcached was renamed to memcached for consistency
Bugfixes¶
fix SIGPIPE crashes (#271)
tests: work around out-of-space for platforms with larger memory pages
lua: fix mistakes in bindings affecting 1.4.0 and 1.5.0 (and 1.99.1-alpha), potentially causing problems in dns64 and workarounds modules
predict module: various fixes (!399)
Improvements¶
add priming module to implement RFC 8109, enabled by default (#220)
add modules helping with system time problems, enabled by default; for details see documentation of detect_time_skew and detect_time_jump
Knot Resolver 1.5.0 (2017-11-02)¶
Bugfixes¶
fix loading modules on Darwin
Improvements¶
new module ta_signal_query supporting Signaling Trust Anchor Knowledge using Keytag Query (RFC 8145 section 5); it is enabled by default
attempt validation for more records but require it for fewer of them (e.g. avoids SERVFAIL when server adds extra records but omits RRSIGs)
Knot Resolver 1.99.1-alpha (2017-10-26)¶
This is an experimental release meant for testing aggressive caching. It contains some regressions and might (theoretically) be even vulnerable. The current focus is to minimize queries into the root zone.
Improvements¶
negative answers from validated NSEC (NXDOMAIN, NODATA)
verbose log is very chatty around cache operations (maybe too much)
Regressions¶
dropped support for alternative cache backends and for some specific cache operations
- caching doesn’t yet work for various cases:
- negative answers without NSEC (i.e. with NSEC3 or insecure)
+cd queries (needs other internal changes)
positive wildcard answers
- spurious SERVFAIL on specific combinations of cached records, printing:
<= bad keys, broken trust chain
make check
a few Deckard tests are broken, probably due to some problems above
also unknown ones?
Knot Resolver 1.4.0 (2017-09-22)¶
Incompatible changes¶
lua: query flag-sets are no longer represented as plain integers. kres.query.* no longer works, and kr_query_t lost trivial methods ‘hasflag’ and ‘resolved’. You can instead write code like qry.flags.NO_0X20 = true.
Bugfixes¶
fix exiting one of multiple forks (#150)
cache: change the way of using LMDB transactions. That in particular fixes some cases of using too much space with multiple kresd forks (#240).
Improvements¶
policy.suffix: update the aho-corasick code (#200)
root hints are now loaded from a zonefile; exposed as hints.root_file(). You can override the path by defining ROOTHINTS during compilation.
policy.FORWARD: work around resolvers adding unsigned NS records (#248)
reduce unneeded records previously put into authority in wildcarded answers
Knot Resolver 1.3.3 (2017-08-09)¶
Security¶
Fix a critical DNSSEC flaw. Signatures might be accepted as valid even if the signed data was not in bailiwick of the DNSKEY used to sign it, assuming the trust chain to that DNSKEY was valid.
Bugfixes¶
iterate: skip RRSIGs with bad label count instead of immediate SERVFAIL
utils: fix possible incorrect seeding of the random generator
modules/http: fix compatibility with the Prometheus text format
Improvements¶
policy: implement remaining special-use domain names from RFC6761 (#205), and make these rules apply only if no other non-chain rule applies
Knot Resolver 1.3.2 (2017-07-28)¶
Security¶
fix possible opportunities to use insecure data from cache as keys for validation
Bugfixes¶
daemon: check existence of config file even if rundir isn’t specified
policy.FORWARD and STUB: use RTT tracking to choose servers (#125, #208)
dns64: fix CNAME problems (#203) It still won’t work with policy.STUB.
- hints: better interpretation of hosts-like files (#204)
also, error out if a bad entry is encountered in the file
dnssec: handle unknown DNSKEY/DS algorithms (#210)
predict: fix the module, broken since 1.2.0 (#154)
Improvements¶
embedded LMDB fallback: update 0.9.18 -> 0.9.21
Knot Resolver 1.3.1 (2017-06-23)¶
Bugfixes¶
modules/http: fix finding the static files (bug from 1.3.0)
policy.FORWARD: fix some cases of CNAMEs obstructing search for zone cuts
Knot Resolver 1.3.0 (2017-06-13)¶
Security¶
Refactor handling of AD flag and security status of resource records. In some cases it was possible for secure domains to get cached as insecure, even for a TLD, leading to disabled validation. It also fixes answering with non-authoritative data about nameservers.
Improvements¶
major feature: support for forwarding with validation (#112). The old policy.FORWARD action now does that; the previous non-validating mode is still available as policy.STUB except that also uses caching (#122).
command line: specify ports via @ but still support # for compatibility
policy: recognize 100.64.0.0/10 as local addresses
layer/iterate: do retry repeatedly if REFUSED, as we can’t yet easily retry with other NSs while avoiding retrying with those who REFUSED
modules: allow changing the directory where modules are found, and do not search the default library path anymore.
Bugfixes¶
validate: fix insufficient caching for some cases (relatively rare)
avoid putting “duplicate” record-sets into the answer (#198)
Knot Resolver 1.2.6 (2017-04-24)¶
Security¶
dnssec: don’t set AD flag for NODATA answers if wildcard non-existence is not guaranteed due to opt-out in NSEC3
Improvements¶
layer/iterate: don’t retry repeatedly if REFUSED
Bugfixes¶
lib/nsrep: revert some changes to NS reputation tracking that caused severe problems to some users of 1.2.5 (#178 and #179)
dnssec: fix verification of wildcarded non-singleton RRsets
dnssec: allow wildcards located directly under the root
layer/rrcache: avoid putting answer records into queries in some cases
Knot Resolver 1.2.5 (2017-04-05)¶
Security¶
layer/validate: clear AD if closest encloser proof has opt-outed NSEC3 (#169)
layer/validate: check if NSEC3 records in wildcard expansion proof has an opt-out
dnssec/nsec: missed wildcard no-data answers validation has been implemented
Improvements¶
modules/dnstap: a DNSTAP support module (Contributed by Vicky Shrestha)
modules/workarounds: a module adding workarounds for known DNS protocol violators
layer/iterate: fix logging of glue addresses
kr_bitcmp: allow bits=0 and consequently 0.0.0.0/0 matches in view and renumber modules.
modules/padding: Improve default padding of responses (Contributed by Daniel Kahn Gillmor)
New kresc client utility (experimental; don’t rely on the API yet)
Bugfixes¶
trust anchors: Improve trust anchors storage format (#167)
trust anchors: support non-root TAs, one domain per file
policy.DENY: set AA flag and clear AD flag
lib/resolve: avoid unnecessary DS queries
lib/nsrep: don’t treat servers with NOIP4 + NOIP6 flags as timeouted
layer/iterate: During packet classification (answer vs. referral) don’t analyze AUTHORITY section in authoritative answer if ANSWER section contains records that have been requested
Knot Resolver 1.2.4 (2017-03-09)¶
Security¶
Knot Resolver 1.2.0 and higher could return AD flag for insecure answer if the daemon received answer with invalid RRSIG several times in a row.
Improvements¶
modules/policy: allow QTRACE policy to be chained with other policies
hints.add_hosts(path): a new property
module: document the API and simplify the code
policy.MIRROR: support IPv6 link-local addresses
policy.FORWARD: support IPv6 link-local addresses
add net.outgoing_{v4,v6} to allow specifying address to use for connections
Bugfixes¶
layer/iterate: some improvements in cname chain unrolling
layer/validate: fix duplicate records in AUTHORITY section in case of WC expansion proof
lua: do not truncate cache size to unsigned
forwarding mode: correctly forward +cd flag
fix a potential memory leak
don’t treat answers that contain DS non-existance proof as insecure
don’t store NSEC3 and their signatures in the cache
layer/iterate: when processing delegations, check if qname is at or below new authority
Knot Resolver 1.2.3 (2017-02-23)¶
Bugfixes¶
Disable storing GLUE records into the cache even in the (non-default) QUERY_PERMISSIVE mode
iterate: skip answer RRs that don’t match the query
layer/iterate: some additional processing for referrals
lib/resolve: zonecut fetching error was fixed
Knot Resolver 1.2.2 (2017-02-10)¶
Bugfixes:¶
Fix -k argument processing to avoid out-of-bounds memory accesses
lib/resolve: fix zonecut fetching for explicit DS queries
hints: more NULL checks
Fix TA bootstrapping for multiple TAs in the IANA XML file
Testing:¶
Update tests to run tests with and without QNAME minimization
Knot Resolver 1.2.1 (2017-02-01)¶
Security:¶
Under certain conditions, a cached negative answer from a CD query would be reused to construct response for non-CD queries, resulting in Insecure status instead of Bogus. Only 1.2.0 release was affected.
Documentation¶
Update the typo in the documentation: The query trace policy is named policy.QTRACE (and not policy.TRACE)
Bugfixes:¶
lua: make the map command check its arguments
Knot Resolver 1.2.0 (2017-01-24)¶
Security:¶
In a policy.FORWARD() mode, the AD flag was being always set by mistake. It is now cleared, as the policy.FORWARD() doesn’t do DNSSEC validation yet.
Improvements:¶
The DNSSEC Validation has been refactored, fixing many resolving failures.
Add module version that checks for updates and CVEs periodically.
Support RFC7830: EDNS(0) padding in responses over TLS.
Support CD flag on incoming requests.
hints module: previously /etc/hosts was loaded by default, but not anymore. Users can now actually avoid loading any file.
DNS over TLS now creates ephemeral certs.
Configurable cache.{min,max}_tll option, with max_ttl defaulting to 6 days.
Option to reorder RRs in the response.
New policy.QTRACE policy to print packet contents
Bugfixes:¶
Trust Anchor configuration is now more robust.
Correctly answer NOTIMPL for meta-types and non-IN RR classes.
Free TCP buffer on cancelled connection.
Fix crash in hints module on empty hints file, and fix non-lowercase hints.
Miscellaneous:¶
It now requires knot >= 2.3.1 to link successfully.
The API+ABI for modules changed slightly.
New LRU implementation.
Knot Resolver 1.1.1 (2016-08-24)¶
Bugfixes:¶
Fix 0x20 randomization with retransmit
Fix pass-through for the stub mode
Fix the root hints IPv6 addresses
Fix dst addr for retries over TCP
Improvements:¶
Track RTT of all tried servers for faster retransmit
DAF: Allow forwarding to custom port
systemd: Read EnvironmentFile and user $KRESD_ARGS
systemd: Update systemd units to be named after daemon