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path: root/src/resolve/resolved-dns-dnssec.c
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2016-01-13resolved: refuse validating wildcard RRs for SOA, NSEC3, DNAMELennart Poettering
2016-01-13resolved: properly handles RRs in domains beginning in an asterisk labelLennart Poettering
Properly handle RRs that begin with an asterisk label. These are the unexpanded forms of wildcard domains and appear in NSEC RRs for example. We need to make sure we handle the signatures of these RRs properly, since they mostly are considered normal RRs, except that the RRSIG labels counter is one off for them, as the asterisk label is always excluded of the signature.
2016-01-13resolved: optimize dnssec_verify_rrset() a bitLennart Poettering
Let's determine the source of synthesis once instead of for each RR in the RRset.
2016-01-13resolved: allocate bounded strings on stack instead of heap, if we canLennart Poettering
2016-01-13resolved: consider inverted RRSIG validity intervals expiredLennart Poettering
2016-01-11resolved: properly look for NSEC/NSEC3 RRs when getting a positive wildcard ↵Lennart Poettering
response This implements RFC 5155, Section 8.8 and RFC 4035, Section 5.3.4: When we receive a response with an RRset generated from a wildcard we need to look for one NSEC/NSEC3 RR that proves that there's no explicit RR around before we accept the wildcard RRset as response. This patch does a couple of things: the validation calls will now identify wildcard signatures for us, and let us know the RRSIG used (so that the RRSIG's signer field let's us know what the wildcard was that generate the entry). Moreover, when iterating trough the RRsets of a response we now employ three phases instead of just two. a) in the first phase we only look for DNSKEYs RRs b) in the second phase we only look for NSEC RRs c) in the third phase we look for all kinds of RRs Phase a) is necessary, since DNSKEYs "unlock" more signatures for us, hence we shouldn't assume a key is missing until all DNSKEY RRs have been processed. Phase b) is necessary since NSECs need to be validated before we can validate wildcard RRs due to the logic explained above. Phase c) validates everything else. This phase also handles RRsets that cannot be fully validated and removes them or lets the transaction fail.
2016-01-11resolved: split up nsec3_hashed_domain() into two callsLennart Poettering
There's now nsec3_hashed_domain_format() and nsec3_hashed_domain_make(). The former takes a hash value and formats it as domain, the latter takes a domain name, hashes it and then invokes nsec3_hashed_domain_format(). This way we can reuse more code, as the formatting logic can be unified between this call and another place.
2016-01-11resolved: drop flags unused parameter from nsec3_is_goodLennart Poettering
2016-01-11basic: introduce generic ascii_strlower_n() call and make use of it everywhereLennart Poettering
2016-01-11resolved: use dns_answer_size() where appropriate to handle NULL DnsAnswerLennart Poettering
2016-01-11resolved: rename suffix_rr → zone_rrLennart Poettering
The domain name for this NSEC3 RR was originally stored in a variable called "suffix", which was then renamed to "zone" in d1511b3338f431de3c95a50a9c1aca297e0c0734. Hence also rename the RR variable accordingly.
2016-01-11resolved: fix NSEC3 iterations limit to what RFC5155 suggestsLennart Poettering
2016-01-06update DNSSEC TODOLennart Poettering
2016-01-05update DNSSEC TODOLennart Poettering
2016-01-05resolved,networkd: add a per-interface DNSSEC settingLennart Poettering
This adds a DNSSEC= setting to .network files, and makes resolved honour them.
2016-01-05resolved: rename "downgrade-ok" mode to "allow-downgrade"Lennart Poettering
After discussing this with Tom, we figured out "allow-downgrade" sounds nicer.
2016-01-05resolved: when caching negative responses, honour NSEC/NSEC3 TTLsLennart Poettering
When storing negative responses, clamp the SOA minimum TTL (as suggested by RFC2308) to the TTL of the NSEC/NSEC3 RRs we used to prove non-existance, if it there is any. This is necessary since otherwise an attacker might put together a faked negative response for one of our question including a high-ttl SOA RR for any parent zone, and we'd use trust the TTL.
2016-01-04update DNSSEC TODOLennart Poettering
2016-01-04resolved: partially implement RFC5011 Trust Anchor supportLennart Poettering
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.
2016-01-04resolved: fix DNSSEC canonical ordering logicLennart Poettering
When applying canonical DNSSEC ordering for an RRset only order by the wire format of the RRs' RDATA, not by the full wire formatting. The RFC isn't particularly clear about this, but this is apparently how it is done. This fixes validation of pentagon.gov's DS RRset.
2016-01-03resolved: never authenticate RRsets with revoked keysLennart Poettering
2016-01-03resolved: print a log message when we ignore an NSEC3 RR with an excessive ↵Lennart Poettering
amount of iterations
2016-01-03Merge pull request #2255 from teg/resolved-fixes-2Lennart Poettering
Fixes to NSEC3 proof v2
2016-01-03resolved: add negative trust anchro support, and add trust anchor ↵Lennart Poettering
configuration files This adds negative trust anchor support and allows reading trust anchor data from disk, from files /etc/systemd/dnssec-trust-anchors.d/*.positive and /etc/systemd/dnssec-trust-anchros.d/*.negative, as well as the matching counterparts in /usr/lib and /run. The positive trust anchor files are more or less compatible to normal DNS zone files containing DNSKEY and DS RRs. The negative trust anchor files contain only new-line separated hostnames for which to require no signing. By default no trust anchor files are installed, in which case the compiled-in root domain DS RR is used, as before. As soon as at least one positive root anchor for the root is defined via trust anchor files this buil-in DS RR is not added though.
2016-01-03resolved: dnssec - properly take wildcards into account in NESC3 proofTom Gundersen
For NXDOMAIN, it is not sufficient to prove that the next-closest enclosure does not exist, we must also prove that there is no wildcard domain directly below the closest enclosure which would synthesise the name that has been requested. For positive responses, in addition to exact matches, we should accept wildcard ones. In that case we must first prove that there is no precise match (i.e., that the closest encounter is not the record itself) and secondly that the source of synthesis exists.
2016-01-03resolved: dnssec - factor out hashed domain generationTom Gundersen
2016-01-03resolved: don't conclude NODATA if CNAME existsTom Gundersen
Instead introduce the new return-code DNSSEC_NSEC_CNAME to indicate this condition. See RFC 6840, Section 4.3.
2016-01-02resolved: don't accept NSEC3 iteration fields unboundedLennart Poettering
2016-01-01resolved: dnssec - add reference to the algorithm we implementTom Gundersen
2016-01-01resolved: dnssec - prepend hashed labels to zone nameTom Gundersen
All hashed names consist of the hashed label prepended to the zone name, not to the closest enclosure.
2016-01-01resolved: dnssec - rename some variablesTom Gundersen
Makes the NSEC3 proof somewhat simpler to follow.
2016-01-01resoled: dnssec - don't refuse to verify answer due to too many unrelated RRsTom Gundersen
Let VERIFY_RRS_MAX be about the max number of RRs in an RRSet that we actually try to verify, not about the total number of RRs in the RRSet.
2016-01-01resolved: dnssec - fix off-by-one in RSA key parsingTom Gundersen
If the first byte of the key is zero, the key-length is stored in the second and third byte (not first and second).
2015-12-29resolved: NSEC3 hash algorithms are distinct from DS digest algorithmsLennart Poettering
Previously, we'd use the same set of identifiers for both, but that's actually incorrect. It didn't matter much since the only NSEC3 hash algorithm defined (SHA-1) is mapped to code 1 which is also what it is encoded as in DS digests, but we really should make sure to use two distinct enumerations.
2015-12-29update DNSSEC TODOLennart Poettering
2015-12-29resolved: add comments referencing various RFCs to various placesLennart Poettering
2015-12-28Merge pull request #2231 from phomes/resolve-misc2Tom Gundersen
Resolve misc2
2015-12-28resolved: update DNSSEC TODOLennart Poettering
2015-12-28resolved: use RRSIG expiry and original TTL for cache managementLennart Poettering
When we verified a signature, fix up the RR's TTL to the original TTL mentioned in the signature, and store the signature expiry information in the RR, too. Then, use that when adding RRs to the cache.
2015-12-28resolved: only keep a single list of supported signature algorithmsLennart Poettering
This removes dnssec_algorithm_supported() and simply uses the algorithm_to_gcrypt() result as indication whether a DNSSEC algorithm is supported. The patch also renames "algorithm" to "md_algorithm", in a few cases, in order to avoid confusion between DNSSEC signature algorithms and gcrypt message digest algorithms.
2015-12-28resolved: add ECDSA signature supportLennart Poettering
2015-12-28resolved: split out RSA-specific code from dnssec_verify_rrset()Lennart Poettering
In preparation for ECDSA support.
2015-12-28resolved: simplify MD algorithm initialization a bitLennart Poettering
2015-12-28resolved: add SHA384 digest supportLennart Poettering
2015-12-28resolve: remove unused variablesThomas Hindoe Paaboel Andersen
2015-12-26resolved: add an automatic downgrade to non-DNSSEC modeLennart Poettering
This adds a mode that makes resolved automatically downgrade from DNSSEC support to classic non-DNSSEC resolving if the configured DNS server is not capable of DNSSEC. Enabling this mode increases compatibility with crappy network equipment, but of course opens up the system to downgrading attacks. The new mode can be enabled by setting DNSSEC=downgrade-ok in resolved.conf. DNSSEC=yes otoh remains a "strict" mode, where DNS resolving rather fails then allow downgrading. Downgrading is done: - when the server does not support EDNS0+DO - or when the server supports it but does not augment returned RRs with RRSIGs. The latter is detected when requesting DS or SOA RRs for the root domain (which is necessary to do proofs for unsigned data)
2015-12-26resolved: if we accepted unauthenticated NSEC/NSEC3 RRs, use them for proofsLennart Poettering
But keep track that the proof is not authenticated.
2015-12-26resolved: be stricter when searching for a DS RR for a DNSKEY RRLennart Poettering
2015-12-26update DNSSEC TODOLennart Poettering
2015-12-26resolved: tighten search for NSEC3 RRs a bitLennart Poettering
Be stricter when searching suitable NSEC3 RRs for proof: generalize the check we use to find suitable NSEC3 RRs, in nsec3_is_good(), and add additional checks, such as checking whether all NSEC3 RRs use the same parameters, have the same suffix and so on.