tree-wide: remove Emacs lines from all files This should be handled fine now by .dir-locals.el, so need to carry that stuff in every file.

resolved: rename dnssec_verify_dnskey() → dnssec_verify_dnskey_by_ds() This should clarify that this is not regular signature-based validation, but validation through DS RR fingerprints.

resolved: partially implement RFC5011 Trust Anchor support With this patch resolved will properly handle revoked keys, but not augment the locally configured trust anchor database with newly learned keys. Specifically, resolved now refuses validating RRsets with revoked keys, and it will remove revoked keys from the configured trust anchors (only until reboot). This patch does not add logic for adding new keys to the set of trust anchors. This is a deliberate decision as this only can work with persistent disk storage, and would result in a different update logic for stateful and stateless systems. Since we have to support stateless systems anyway, and don't want to encourage two independent upgrade paths we focus on upgrading the trust anchor database via the usual OS upgrade logic. Whenever a trust anchor entry is found revoked and removed from the trust anchor a recognizable log message is written, encouraging the user to update the trust anchor or update his operating system.

resolved: internalize string buffer of dns_resource_record_to_string() Let's simplify usage and memory management of DnsResourceRecord's dns_resource_record_to_string() call: cache the formatted string as part of the object, and return it on subsequent calls, freeing it when the DnsResourceRecord itself is freed.

resolved: add support NSEC3 proofs, as well as proofs for domains that are OK to be unsigned This large patch adds a couple of mechanisms to ensure we get NSEC3 and proof-of-unsigned support into place. Specifically: - Each item in an DnsAnswer gets two bit flags now: DNS_ANSWER_AUTHENTICATED and DNS_ANSWER_CACHEABLE. The former is necessary since DNS responses might contain signed as well as unsigned RRsets in one, and we need to remember which ones are signed and which ones aren't. The latter is necessary, since not we need to keep track which RRsets may be cached and which ones may not be, even while manipulating DnsAnswer objects. - The .n_answer_cachable of DnsTransaction is dropped now (it used to store how many of the first DnsAnswer entries are cachable), and replaced by the DNS_ANSWER_CACHABLE flag instead. - NSEC3 proofs are implemented now (lacking support for the wildcard part, to be added in a later commit). - Support for the "AD" bit has been dropped. It's unsafe, and now that we have end-to-end authentication we don't need it anymore. - An auxiliary DnsTransaction of a DnsTransactions is now kept around as least as long as the latter stays around. We no longer remove the auxiliary DnsTransaction as soon as it completed. THis is necessary, as we now are interested not only in the RRsets it acquired but also in its authentication status.

resolve: fix indendation

resolved: add basic proof of non-existance support for NSEC+NSEC3 Note that this is not complete yet, as we don't handle wildcard domains correctly, nor handle domains correctly that use empty non-terminals.

resolved: apparently not all names are used in canonical form for DNSSEC validation Specifically, it appears as if the NSEC next domain name should be in the original casing rather than canonical form, when validating.

resolved: chase DNSKEY/DS RRs when doing look-ups with DNSSEC enabled This adds initial support for validating RRSIG/DNSKEY/DS chains when doing lookups. Proof-of-non-existance, or proof-of-unsigned-zones is not implemented yet. With this change DnsTransaction objects will generate additional DnsTransaction objects when looking for DNSKEY or DS RRs to validate an RRSIG on a response. DnsTransaction objects are thus created for three reasons now: 1) Because a user asked for something to be resolved, i.e. requested by a DnsQuery/DnsQueryCandidate object. 2) As result of LLMNR RR probing, requested by a DnsZoneItem. 3) Because another DnsTransaction requires the requested RRs for validation of its own response. DnsTransactions are shared between all these users, and are GC automatically as soon as all of these users don't need a specific transaction anymore. To unify the handling of these three reasons for existance for a DnsTransaction, a new common naming is introduced: each DnsTransaction now tracks its "owners" via a Set* object named "notify_xyz", containing all owners to notify on completion. A new DnsTransaction state is introduced called "VALIDATING" that is entered after a response has been receieved which needs to be validated, as long as we are still waiting for the DNSKEY/DS RRs from other DnsTransactions. This patch will request the DNSKEY/DS RRs bottom-up, and then validate them top-down. Caching of RRs is now only done after verification, so that the cache is not poisoned with known invalid data. The "DnsAnswer" object gained a substantial number of new calls, since we need to add/remove RRs to it dynamically now.

resolved: move algorithm/digest definitions into resolved-dns-rr.h After all, they are for flags and parameters of RRs and already relevant when dealing with RRs outside of the serialization concept.

resolved: don't accept expired RRSIGs

resolved: add basic DNSSEC support This adds most basic operation for doing DNSSEC validation on the client side. However, it does not actually add the verification logic to the resolver. Specifically, this patch only includes: - Verifying DNSKEY RRs against a DS RRs - Verifying RRSets against a combination of RRSIG and DNSKEY RRs - Matching up RRSIG RRs and DNSKEY RRs - Matching up RR keys and RRSIG RRs - Calculating the DNSSEC key tag from a DNSKEY RR All currently used DNSSEC combinations of SHA and RSA are implemented. Support for MD5 hashing and DSA or EC cyphers are not. MD5 and DSA are probably obsolete, and shouldn't be added. EC should probably be added eventually, if it actually is deployed on the Internet.