- knot-resolver-users - lists.nic.cz

CentOS 7 package ships writable /etc/knot-resolver

by Anand Buddhdev

Hello Knot resolver folks, and especially the packagers, I've noticed that the CentOS 7 packages published by CZNIC ship with /etc/knot-resolver writable by the "knot-res" user (the directory mode is 0775). It seems that the directory is writable, because kresd (running as user knot-res) runs a lua script to manage the /etc/knot-resolver/root.keys file. My sysadmin mind is suspicious of this setup. If any other modules of kresd have a bug, they have the potential to modify config files in /etc/knot-resolver. My thinking is that the root.keys file should be installed in /var/cache/knot-resolver, and that is writable by "knot-res". Could someone please explain to me why the config directory is writable by an unprivileged user? Is there a good reason I'm not seeing for this setup? Regards, Anand Buddhdev

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Knot Resolver - module hints - reload?

by Milan Jeskynka Kazatel

Hello, Could someone help me to understand the behavior of Knot Resolver? Can I somehow process a change in the list of static records for knot resolver like a command for reloading configuration? If I have in the kresd.conf file a module modules = { 'hints> iterate', - Add static records to resolver ... ... and the list is located - Load static records hints.add_hosts ('/ etc / knot-resolver / static_records.txt') how can I reload the change in the static_records.txt list for the kresd @ 1 service Or should I always restart the daemon kresd @ 1 systemctl restart Kresd @ 1 Thanks for any advice, Regadrs, -- Smil Milan Jeskyňka Kazatel

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Knot Resolver 4.2.0

by Tomas Krizek

Dear Knot Resolver users, Knot Resolver 4.2.0 has been released! Improvements ------------ - queries without RD bit set are REFUSED by default (!838) - support forwarding to multiple targets (!825) Bugfixes -------- - tls_client: fix issue with TLS session resumption (#489) - rebinding module: fix another false-positive assertion case (!851) Module API changes ------------------ - kr_request::add_selected is now really put into answer, instead of the "duplicate" ::additional field (#490) Full changelog: https://gitlab.labs.nic.cz/knot/knot-resolver/raw/v4.2.0/NEWS Sources: https://secure.nic.cz/files/knot-resolver/knot-resolver-4.2.0.tar.xz GPG signature: https://secure.nic.cz/files/knot-resolver/knot-resolver-4.2.0.tar.xz.asc Documentation: https://knot-resolver.readthedocs.io/en/v4.2.0/ -- Tomas Krizek PGP: 4A8B A48C 2AED 933B D495 C509 A1FB A5F7 EF8C 4869

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Re: [knot-resolver-users] Specify wildcard subdomain static hints

by Vladimír Čunát

Hello, first note the change to the correct mailing-list. On 7/29/19 10:20 AM, Balakrishnan B wrote: > I am trying to add wildcard static hints to catch all local domains like > below. But does not seem to work. > > hints['nextcloud.local'] = '127.0.0.1' # This works fine > hints['*.local'] = '127.0.0.1' > hints['.local'] = '127.0.0.1' > > DNSMasq supports this like https://stackoverflow.com/a/22551303 > > Is there way to do this in knot? No, I don't think there's a good way currently. The hints module only supports exact names with A and AAAA and corresponding PTR, like in /etc/hosts files. With our [RPZ] you can do wildcards, but there's no support for positive answers (so you need to do NXDOMAIN or similar denials). BTW, note that .local is reserved for [mDNS] protocol, in particular kresd might never get to such requests because it's "only" a DNS server: > 3. Name resolution APIs and libraries SHOULD recognize these names as > special and SHOULD NOT send queries for these names to their > configured (unicast) caching DNS server(s). > [RPZ] https://knot-resolver.readthedocs.io/en/stable/modules.html#c.policy.rpz [mDNS] https://tools.ietf.org/html/rfc6762#section-22.1 --Vladimir

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debian repo: http -> https

by Christoph

The instructions on: https://www.knot-resolver.cz/download/ read: " wget https://secure.nic.cz/files/knot-resolver/knot-resolver-release.deb dpkg -i knot-resolver-release.deb apt update && apt install -y knot-resolver " these instructions result in an http://.. URL in: /etc/apt/sources.list.d/knot-resolver-latest.list I'd suggest to change it to https://..

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Knot Resolver 4.1.0

by Petr Špaček

-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Dear Knot Resolver users, Knot Resolver 4.1.0 has been released! This is a minor release with couple improvements and many bugfixes, including security fixes for CVE-2019-10190 and CVE-2019-10191. Packages for supported distributions are now available from https://www.knot-resolver.cz/download/ Highlights ========== - - security fixes, we encourage all users to upgrade as soon as possible - - new garbage collector improves cache utilization on busy machines - - ARM64 (aarch64) is now experimentally supported, please report issues - - compatibility with non-standard DoH clients was improved Full release notes: Knot Resolver 4.1.0 (2019-07-10) ================================ Security - -------- - - fix CVE-2019-10190: do not pass bogus negative answer to client (!827) - - fix CVE-2019-10191: do not cache negative answer with forged QNAME+QTYPE (!839) Improvements - ------------ - - new cache garbage collector is available and enabled by default (#257) This improves cache efficiency on big installations. - - DNS-over-HTTPS: unknown HTTP parameters are ignored to improve compatibility with non-standard clients (!832) - - DNS-over-HTTPS: answers include `access-control-allow-origin: *` which allows JavaScript to use DoH endpoint (!823). - - http module: support named AF_UNIX stream sockets (again) - - aggressive caching is disabled on minimal NSEC* ranges (!826) This improves cache effectivity with DNSSEC black lies and also accidentally works around bug in proofs-of-nonexistence from F5 BIG-IP load-balancers. - - aarch64 support, even kernels with ARM64_VA_BITS >= 48 (#216, !797) This is done by working around a LuaJIT incompatibility. Please report bugs. - - lua tables for C modules are more strict by default, e.g. `nsid.foo` will throw an error instead of returning `nil` (!797) - - systemd: basic watchdog is now available and enabled by default (#275) Bugfixes - -------- - - TCP to upstream: fix unlikely case of sending out wrong message length (!816) - - http module: fix problems around maintenance of ephemeral certs (!819) - - http module: also send intermediate TLS certificate to clients, if available and luaossl >= 20181207 (!819) - - send EDNS with SERVFAILs, e.g. on validation failures (#180, !827) - - prefill module: avoid crash on empty zone file (#474, !840) - - rebinding module: avoid excessive iteration on blocked attempts (!842) - - rebinding module: fix crash caused by race condition (!842) - - rebinding module: log each blocked query only in verbose mode (!842) - - cache: automatically clear stale reader locks (!844) Module API changes - ------------------ - - lua modules may omit casting parameters of layer functions (!797) - -- Petr Špaček @ CZ.NIC -----BEGIN PGP SIGNATURE----- iQIzBAEBCgAdFiEEvibrucvgWbORDKNbzo3WoaUKIeQFAl0mBC0ACgkQzo3WoaUK IeT3uw/9Fqz2PWYmEtF50nlnFIyM44EAClQFVboM8djVQVffN347nZTo4WPI+rsj exUg5tYKIEC6xrihRLwojbTfFcGVXcEHo0NZsvyv51qIP+lT6yHOVMz+tckmGyPI qG4JxvF7juUz1oLNCLUJfuZX/rOBgcOID2hga6q8ZXmkE5GFkyPsz7giaxjNWCGY Hf+uxzR2oezd4GGaOS2bIpqSjBmQwjaLvN3odG0xGZEHQCm+MkblVIbpiKuyR79e CulWcLNU1KL4V4o/rF5BUXHCnArGP/TM0JoVifPZepZVyB8xMEfBuyew9k1EAuX6 +5oJ9H1JcsftMtBgGUtksltTVK+9Mst9Rc52oiP5RA8ffpc5j0TtQi/lgNSgGnfQ P10t7fnlotseBYsHeQ0dm54TlGKBgsECuk1/wgjlytbUU9AUQMkmop696xZEcw1w gVY7FhAq09ciqtNTKuPJLoNTN/uhIdnyvt496Xf15OA3znZlMxdrI+rdVvf3btX/ SV9/bzNyWtJOhiYoN4hIPUqcvq6rFqxBbZpDA3pX9ks/lsWil7Y8sm96GzOjvaSx EjhDbBaFLBtX4kOPbrREDs8DbCTsxD1rLEruPos+Mp8PfAISEa/RvjyhuI/yyjwE qpNksYdKNHeniYEcycJ1khJBs1cz+9GlBFdCnSdFG2tFFu4nY4g= =pAEs -----END PGP SIGNATURE-----

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Pre-release announcement: 4.1.0 security release on Wednesday 2019-07-10

by Petr Špaček

Hello, this is pre-release announcement. We are going to release Knot Resolver 4.1.0 with two security fixes on Wednesday 2019-07-10. This release includes fixes for CVE-2019-10190 and CVE-2019-10191. We advise all users to upgrade to version 4.1.0 as soon as possible. Version 4.1.0 is fully is compatible with version 4.0.0 and no manual steps are required during upgrade. Pre-built software packages and source code will be made available from https://www.knot-resolver.cz/download/ during Wednesday 2019-07-10. Customers with formal support contracts with CZ.NIC can receive fixes immediatelly. Software packages provided by Linux distributions (i.e. not supplied by CZ.NIC) will follow usual release cycle of respective vendors. CZ.NIC cannot guarantee availability and timeline related to fixes in these packages. Nevertheless, following vendors received security patches in advance: ALT Linux, Amazon Linux AMI, Arch Linux, Chrome OS, CloudLinux, CoreOS, Debian, Gentoo, Openwall, Oracle, Red Hat, Slackware, SUSE, Ubuntu, Wind River. Please send your questions to mailing list knot-resolver-users(a)lists.nic.cz. -- Petr Špaček @ CZ.NIC

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network configuration via systemd sockets - feedback?

by Tomas Krizek

Hi, I'd like to ask your opinion about knot-resolver's systemd integration - in particular, about the network configuration which is currently done via drop-in files for systemd sockets - kresd.socket, kresd-tls.socket, kresd-doh.socket and kresd-webmgmt.socket. [network-config-doc] Have you had any issues while trying to configure network interfaces for kresd? Do you find the benefits of socket activation worth the extra complexity of network configuration? (socket activation enables kresd to be executed under non-priviledged user and the process doesn't require any extra capabilities) All the newtork configuration could take place in kresd.conf via net.listen() [net-listen-exmaple] if we decided to drop the socket activation feature. However, this would require we start the service with the CAP_NET_BIND_SERVICE capability, which could be dropped once kresd binds to the ports. Any feedback is welcome! [network-config-doc] - https://knot-resolver.readthedocs.io/en/stable/daemon.html#network-configur… [net-listen-exmaple] - https://knot-resolver.readthedocs.io/en/stable/daemon.html#c.net.listen -- Tomas Krizek PGP: 4A8B A48C 2AED 933B D495 C509 A1FB A5F7 EF8C 4869

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some early kresd 4.0.0 DoH observations

by Christoph

Hi, to see whether kresd 4.0.0 would do a comparable or better job than doh-httpproxy we analyzed failure rates by looking at HTTP response codes for each setup and found some significant differences for HTTP response code 400: sample size: 1 000 000 HTTP requests for each run HTTP Code [1] [2] [3] -------------------------------- 200 93.96 97.04 96.33 499 3.28 2.45 3.11 400 2.07 0.18 0.22 <<< 415 0.68 0.32 0.34 408 0.002 0.002 0.002 413 0.001 0 0 Numbers show percent. setups: [1] nginx -> (http, no tls) kresd [2] nginx -> (http, no tls) doh-httpproxy -> (udp/53) unbound To reduce the likelihood of measuring unrelated issues (like issues caused by qname minimization differences between unbound and kresd) we also used kresd as DNS resolver without touching its DoH code path: [3] nginx -> (http, no tls) doh-httpproxy -> (udp/53) kresd The HTTP request rate for [1] was slightly lower when compared with [2] and [3]. To be more precise, doh-httproxy services was configured with two running instances as described here: https://facebookexperimental.github.io/doh-proxy/tutorials/nginx-dohhttppro… version information: kresd 4.0.0 nginx 1.14.2 unbound 1.9.0 https://github.com/facebookexperimental/doh-proxy @ 9f943a4c232bd018ae155b7839a6b4e13181a5fd This information on its own is not very useful but it might help motivate further tests in a test-environment with no real end-user traffic that allows for more verbose logging. We would also like to hear from other kresd DoH adopters if they observe similar failure rates on their setups. Some open questions for further tests: - How reproducible are these results? - Does the HTTP method (GET vs. POST) change the error rate? - Can the error rate be reduced by running multiple kresd backends? (nginx sending requests to two kresd bakcends) - Is the DNS transaction ID of always 0 as per RFC8484 an issue when kresd is not also terminating the initial HTTPS connection from the DoH client? (from a backend's perspective two distinct queries might look identical when a reverse proxy sits between the DoH client and kresd) regards, Christoph

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trying to use resolver on lan

by B. Cook

I'm new to knot resolver (krsed). Running kresd in runit and logging via svlogd. I'm trying to run kresd on a lan with internal ip addresses and internal domains. I can currently do this with dnsmasq and unbound, but I wanted to see how kresd would do on the client facing edge. I have an Active Directory domain which I've inherited (domain.local) and I've made a building.domain dns infrastructure for the different buildings. (building-red.domain, building-orange.domain, building-green.domain, etc..) There were two AD dns servers doing all the DNS.. There is now a pihole server and dnsmasq helping to offset the queries. I'm looking to put up a kresd on the :53 and move the current dnsmasq installs to :57 and have kresd forward to them. When I do this my building.domain and domain.local are not resolvable. What am I missing? Unbound has a private-address and private-domain which handles this. Does knot resolver have something similar? egrep -v "\-\-" /etc/knot-resolver/config <code> net.listen('10.20.0.43', 53) trust_anchors.remove('.') modules = { 'policy', 'stats', 'predict' } cache.size = 100*MB cache.storage = 'lmdb:///var/cache/knot-resolver/' user( 'knot-resolver', 'knot-resolver' ) predict.config({ window = 20, period = 72 }) policy.add( policy.all( policy.FORWARD( { '10.20.0.43@57', '10.20.0.53@57' } ))) </code> Below is an excerpt from the kresd logs captured via svlogd showing the nxdomain return.. 2019-05-22_18:19:53.06750 [00000.00][plan] plan 'squid.tech.pcsd.' type 'A' uid [35568.00] 2019-05-22_18:19:53.06756 [35568.00][iter] 'squid.tech.pcsd.' type 'A' new uid was assigned .01, parent uid .00 2019-05-22_18:19:53.06758 [35568.01][cach] => trying zone: ., NSEC, hash 0 2019-05-22_18:19:53.06759 [35568.01][cach] => NSEC sname: covered by: pccw. -> pe., new TTL 83379 2019-05-22_18:19:53.06760 [35568.01][cach] => NSEC wildcard: covered by: . -> aaa., new TTL 84454 2019-05-22_18:19:53.06761 [35568.01][cach] => writing RRsets: +++ 2019-05-22_18:19:53.06762 [35568.01][iter] <= rcode: NXDOMAIN 2019-05-22_18:19:53.06768 [35568.01][resl] AD: request NOT classified as SECURE 2019-05-22_18:19:53.06773 [35568.01][resl] finished: 0, queries: 1, mempool: 16400 B and this is another request that worked successfully 2019-05-22_18:19:53.07382 [00000.00][plan] plan 'r6---sn-8xgp1vo-2iae.googlevideo.com.' type 'A' uid [24882.00] 2019-05-22_18:19:53.07384 [24882.00][iter] 'r6---sn-8xgp1vo-2iae.googlevideo.com.' type 'A' new uid was assigned .01, parent uid .00 2019-05-22_18:19:53.07388 [24882.01][cach] => skipping unfit CNAME RR: rank 020, new TTL -144 2019-05-22_18:19:53.07389 [24882.01][cach] => no NSEC* cached for zone: googlevideo.com. 2019-05-22_18:19:53.07389 [24882.01][cach] => skipping zone: googlevideo.com., NSEC, hash 0;new TTL -123456789, ret -2 2019-05-22_18:19:53.07389 [24882.01][cach] => skipping zone: googlevideo.com., NSEC, hash 0;new TTL -123456789, ret -2 2019-05-22_18:19:53.07390 [ ][nsre] score 21 for 10.20.0.43#00057; cached RTT: 19 2019-05-22_18:19:53.07391 [ ][nsre] score 40001 for 10.20.0.53#00057; cached RTT: 12666 2019-05-22_18:19:53.07391 [24882.01][resl] => id: '07414' querying: '10.20.0.43#00057' score: 21 zone cut: '.' qname: 'R6---sN-8Xgp1VO-2iae.goOgLeVIDeO.CoM.' qtype: 'A' proto: 'udp' here is dig showing that the entry does exist.. ; <<>> DiG 9.14.2 <<>> @10.20.0.43 -p 53 -t any squid.tech.pcsd ; (1 server found) ;; global options: +cmd ;; Got answer: ;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 17967 ;; flags: qr aa rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 0, ADDITIONAL: 1 ;; OPT PSEUDOSECTION: ; EDNS: version: 0, flags:; udp: 4096 ;; QUESTION SECTION: ;squid.tech.pcsd. IN ANY ;; ANSWER SECTION: squid.tech.pcsd. 300 IN A 10.20.0.69 ;; Query time: 3 msec ;; SERVER: 10.20.0.43#53(10.20.0.43) ;; MSG SIZE rcvd: 60 As I said I'm still new to kresd and it's logging format so please excuse my ignorance if the answer is obvious.. I've been reading all that I can, and I couldn't find a use case that was like mine in the documentation.. (I did find two things that were causing me problems with upstream providers in unbound because of the docs.. which is why I'm looking to try it on the lan and see what happens.. ) Thank you for taking the time to read this. I'm looking to fortify and make things more resilient with the network so that I can focus on finishing other projects.. and from what I can see.. knot will totally help me with that. Again, thanks for this piece of software - greatly appreciated. After squidguard and pihole this is what I'm sending to the outiside world (thanks to krsed.. https://imgur.com/a/tlcC6Jx -- This message may contain confidential information and is intended only for the individual(s) named. If you are not an intended recipient you are not authorized to disseminate, distribute or copy this e-mail. Please notify the sender immediately if you have received this e-mail by mistake and delete this e-mail from your system.

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