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path: root/src/resolve/resolved-dns-packet.c
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2016-02-10tree-wide: remove Emacs lines from all filesDaniel Mack
This should be handled fine now by .dir-locals.el, so need to carry that stuff in every file.
2016-02-07treewide: fix typos and spacingTorstein Husebø
2016-01-29resolved: add macro to compare sized fieldsZbigniew Jędrzejewski-Szmek
For consistency, generic.size is renamed to generic.data_size. nsec3.next_hashed_name comparison was missing a size check.
2016-01-28resolved: OPENPGPKEY recordsZbigniew Jędrzejewski-Szmek
2016-01-28resolved: TLSA recordsZbigniew Jędrzejewski-Szmek
2016-01-25resolved: fix RR key reduction logicLennart Poettering
Fixes #2380.
2016-01-19Merge pull request #2357 from keszybz/warnings-2Lennart Poettering
Remove gcc warnings v2
2016-01-18resolved: rework IDNA logicLennart Poettering
Move IDNA logic out of the normal domain name processing, and into the bus frontend calls. Previously whenever comparing two domain names we'd implicitly do IDNA conversion so that "pöttering.de" and "xn--pttering-n4a.de" would be considered equal. This is problematic not only for DNSSEC, but actually also against he IDNA specs. Moreover it creates problems when encoding DNS-SD services in classic DNS. There, the specification suggests using UTF8 encoding for the actual service name, but apply IDNA encoding to the domain suffix. With this change IDNA conversion is done only: - When the user passes a non-ASCII hostname when resolving a host name using ResolveHostname() - When the user passes a non-ASCII domain suffix when resolving a service using ResolveService() No IDNA encoding is done anymore: - When the user does raw ResolveRecord() RR resolving - On the service part of a DNS-SD service name Previously, IDNA encoding was done when serializing names into packets, at a point where information whether something is a label that needs IDNA encoding or not was not available, but at a point whether it was known whether to generate a classic DNS packet (where IDNA applies), or an mDNS/LLMNR packet (where IDNA does not apply, and UTF8 is used instead for all host names). With this change each DnsQuery object will now maintain two copies of the DnsQuestion to ask: one encoded in IDNA for use with classic DNS, and one encoded in UTF8 for use with LLMNR and MulticastDNS.
2016-01-18resolve: fix return value from dns_packet_append_rr()Zbigniew Jędrzejewski-Szmek
2016-01-17resolved: try to reduce number or DnsResourceKeys we keep around by merging themLennart Poettering
Quite often we read the same RR key multiple times from the same message. Try to replace them by a single object when we notice this. Do so again when we add things to the cache. This should reduce memory consumption a tiny bit.
2016-01-17resolved: ignore invalid OPT RRs in incoming packetsLennart Poettering
This validates OPT RRs more rigorously, before honouring them: if we any of the following condition holds, we'll ignore them: a) Multiple OPT RRs in the same message b) OPT RR not owned by the root domain c) OPT RR in the wrong section (Belkin routers do this) d) OPT RR contain rfc6975 algorithm data (Belkin routers do this) e) OPT version is not 0 f) OPT payload doesn't add up with the lengths Note that d) may be an indication that the server just blindly copied OPT data from the response into the reply. RFC6975 data is only supposed to be included in queries, and we do so. It's not supposed to be included in responses (and the RFC is very clear on that). Hence if we get it back in a reply, then the server probably just copied the OPT RR.
2016-01-11basic: introduce generic ascii_strlower_n() call and make use of it everywhereLennart Poettering
2016-01-11resolved: be less strict where the OPT pseudo-RR is placedLennart Poettering
This increases compatibility with crappy Belkin routers.
2016-01-02resolved: fix serialization of the root domainLennart Poettering
2015-12-29resolved: append RFC6975 algorithm data to EDNS OPT RRLennart Poettering
2015-12-29resolved: reset RR TTL to 0, if MSB is setLennart Poettering
RFC 2181, Section 8 suggests to treat an RR TTL with the MSB set as 0. Implement this.
2015-12-27resolved: rework OPT RR generation logicLennart Poettering
This moves management of the OPT RR out of the scope management and into the server and packet management. There are now explicit calls for appending and truncating the OPT RR from a packet (dns_packet_append_opt() and dns_packet_truncate_opt()) as well as a call to do the right thing depending on a DnsServer's feature level (dns_server_adjust_opt()). This also unifies the code to pick a server between the TCP and UDP code paths, and makes sure the feature level used for the transaction is selected at the time the server is picked, and not changed until the next time we pick a server. The server selction code is now unified in dns_transaction_pick_server(). This all fixes problems when changing between UDP and TCP communication for the same server, and makes sure the UDP and TCP codepaths are more alike. It also makes sure we never keep the UDP port open when switchung to TCP, so that we don't have to handle incoming datagrams on the latter we don't expect. As the new code picks the DNS server at the time we make a connection, we don't need to invalidate the DNS server anymore when changing to the next one, thus dns_transaction_next_dns_server() has been removed.
2015-12-26resolved: don't unnecessarily allocate memory in dns_packet_append_name()Lennart Poettering
When compression support is off, there's no point in duplicating the name string. Hence, don't do it.
2015-12-26resolved: don't choke on NSEC/NSEC3 RRs with no bitmapLennart Poettering
This might happen in some cases (empty non-terminals...) and we should not choke on it.
2015-12-18resolved: rework mDNS cache-flush bit handlingLennart Poettering
This adds a new DnsAnswer item flag "DNS_ANSWER_SHARED_OWNER" which is set for mDNS RRs that lack the cache-flush bit. The cache-flush bit is removed from the DnsResourceRecord object in favour of this. This also splits out the code that removes previous entries when adding new positive ones into a new separate call dns_cache_remove_previous().
2015-12-18resolved: don't honour mDNS cache-flush bit for OPT RRsLennart Poettering
OPT RRs after all use the class field for other purposes than actually encoding a class, hence the cache flush bit doesn't apply really.
2015-12-18resolved: make use of dns_{class|type}_is_{pseudo|valid_rr}() everywhereLennart Poettering
2015-12-18resolved: refuse accepting EDNS0 OPT RRs with a non-root domainLennart Poettering
2015-12-18resolved: add support NSEC3 proofs, as well as proofs for domains that are ↵Lennart Poettering
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.
2015-12-14resolved: when serializing NSEC3 windows, don't write more windows than ↵Lennart Poettering
necessary
2015-12-14resolved: constify a parameterLennart Poettering
2015-12-14resolved: apparently not all names are used in canonical form for DNSSEC ↵Lennart Poettering
validation Specifically, it appears as if the NSEC next domain name should be in the original casing rather than canonical form, when validating.
2015-12-14treewide: fix typos and indentationTorstein Husebø
2015-12-11resolved: generalize DNS RR type validity checksLennart Poettering
Check the validity of RR types as we parse or receive data from IPC clients, and use the same code for all of them.
2015-12-11resolved: refuse OPT RRs in incoming packets that are not in the additional ↵Lennart Poettering
section We later rely that the DnsAnswer object contains all RRs from the original packet, at least when it comes to the answer and authorization sections, hence we better make sure we don#t silently end up removing an OPT RR from these two sections.
2015-12-11resolved: no need to check for NULL explicitly before invoking ↵Lennart Poettering
dns_packet_unref()
2015-12-10resolved: cache - don't flush the cache of mDNS records unneccesarilyTom Gundersen
When the DNS_RESOURCE_KEY_CACHE_FLUSH flag is not set for an mDNS packet, we should not flush the cache for RRs with matching keys. However, we were unconditionally flushing the cache also for these packets. Now mark all packets as cache_flush by default, except for these mDNS packets, and respect that flag in the cache handling. This fixes 90325e8c2e559a21ef0bc2f26b844c140faf8020.
2015-12-10resolved: split out check whether reply matches our questionLennart Poettering
It's complicated enough, it deserves its own call. (Also contains some unrelated whitespace, comment and assertion changes)
2015-12-10resolved: IXFR and AXFR cannot be the type of RRs, only of RR keysLennart Poettering
Enforce this while parsing RRs.
2015-12-10resolved: when parsing DNS packets, handle OPT RR speciallyLennart Poettering
As soon as we encounter the OPT RR while parsing, store it in a special field in the DnsPacket structure. That way, we won't be confused if we iterate through RRs, and can check that there's really only one of these RRs around.
2015-12-10resolved: add support for linked packetsDaniel Mack
For mDNS, we need to support the TC bit in case the list of known answers exceed the maximum packet size. For this, add a 'more' pointer to DnsPacket for an additional packet. When a packet is unref'ed, the ->more packet is also unrefed, so it sufficient to only keep track of the 1st packet in a chain.
2015-12-10resolved: add dns_packet_set_flags()Daniel Mack
We need to support the TC bit in queries in case known answers exceed the maximum packet size. Factor out the flags compilation to dns_packet_set_flags() and make it externally available.
2015-12-08resolved: allow name compression in NSEC recordsDaniel Mack
2015-12-08resolved: add cache flush flag to DnsResourceKeyDaniel Mack
MDNS has a 'key cache flush' flag for records which must be masked out for the parsers to do our right thing. We will also use that flag later (in a different patch) in order to alter the cache behavior.
2015-12-08resolved: add packet header details for mDNSDaniel Mack
Validate mDNS queries and responses by looking at some header fields, add mDNS flags.
2015-12-03resolved: introduce a dnssec_mode setting per scopeLennart Poettering
The setting controls which kind of DNSSEC validation is done: none at all, trusting the AD bit, or client-side validation. For now, no validation is implemented, hence the setting doesn't do much yet, except of toggling the CD bit in the generated messages if full client-side validation is requested.
2015-12-03resolved: move algorithm/digest definitions into resolved-dns-rr.hLennart Poettering
After all, they are for flags and parameters of RRs and already relevant when dealing with RRs outside of the serialization concept.
2015-12-02resolved: add code to generate the wire format for a single RRLennart Poettering
This adds dns_resource_record_to_wire_format() that generates the raw wire-format of a single DnsResourceRecord object, and caches it in the object, optionally in DNSSEC canonical form. This call is used later to generate the RR serialization of RRs to verify. This adds four new fields to DnsResourceRecord objects: - wire_format points to the buffer with the wire-format version of the RR - wire_format_size stores the size of that buffer - wire_format_rdata_offset specifies the index into the buffer where the RDATA of the RR begins (i.e. the size of the key part of the RR). - wire_format_canonical is a boolean that stores whether the cached wire format is in DNSSEC canonical form or not. Note that this patch adds a mode where a DnsPacket is allocated on the stack (instead of on the heap), so that it is cheaper to reuse the DnsPacket object for generating this wire format. After all we reuse the DnsPacket object for this, since it comes with all the dynamic memory management, and serialization calls we need anyway.
2015-12-02resolved: add code to map DNSSEC digest types to strings and backLennart Poettering
2015-12-02resolved: store DNSKEY fields flags+protocol as-isLennart Poettering
When verifying signatures we need to be able to verify the original data we got for an RR set, and that means we cannot simply drop flags bits or consider RRs invalid too eagerly. Hence, instead of parsing the DNSKEY flags store them as-is. Similar, accept the protocol field as it is, and don't consider it a parsing error if it is not 3. Of course, this means that the DNSKEY handling code later on needs to check explicit for protocol != 3.
2015-12-02resolved: add RFC 5702 defined DNSSEC algorithms to tableLennart Poettering
2015-12-02resolved: simplify dns_packet_append_string()Lennart Poettering
It essentially does the same as dns_packet_append_raw_string(), hence make it a wrapper around it.
2015-11-27resolved: set the DNSSEC OK (DO) flagTom Gundersen
This indicates that we can handle DNSSEC records (per RFC3225), even if all we do is silently drop them. This feature requires EDNS0 support. As we do not yet support larger UDP packets, this feature increases the risk of getting truncated packets. Similarly to how we fall back to plain UDP if EDNS0 fails, we will fall back to plain EDNS0 if EDNS0+DO fails (with the same logic of remembering success and retrying after a grace period after failure).
2015-11-27resolved: implement minimal EDNS0 supportTom Gundersen
This is a minimal implementation of RFC6891. Only default values are used, so in reality this will be a noop. EDNS0 support is dependent on the current server's feature level, so appending the OPT pseudo RR is done when the packet is emitted, rather than when it is assembled. To handle different feature levels on retransmission, we strip off the OPT RR again after sending the packet. Similarly, to how we fall back to TCP if UDP fails, we fall back to plain UDP if EDNS0 fails (but if EDNS0 ever succeeded we never fall back again, and after a timeout we will retry EDNS0).
2015-11-27resolved: rr - add OPT pseudo-rr supportTom Gundersen
Needed for EDNS0.