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daa908e9f4
the vendored dns resolver code is a copy of the go stdlib dns resolver, with awareness of the "authentic data" (i.e. dnssec secure) added, as well as support for enhanced dns errors, and looking up tlsa records (for dane). ideally it would be upstreamed, but the chances seem slim. dnssec-awareness is added to all packages, e.g. spf, dkim, dmarc, iprev. their dnssec status is added to the Received message headers for incoming email. but the main reason to add dnssec was for implementing dane. with dane, the verification of tls certificates can be done through certificates/public keys published in dns (in the tlsa records). this only makes sense (is trustworthy) if those dns records can be verified to be authentic. mox now applies dane to delivering messages over smtp. mox already implemented mta-sts for webpki/pkix-verification of certificates against the (large) pool of CA's, and still enforces those policies when present. but it now also checks for dane records, and will verify those if present. if dane and mta-sts are both absent, the regular opportunistic tls with starttls is still done. and the fallback to plaintext is also still done. mox also makes it easy to setup dane for incoming deliveries, so other servers can deliver with dane tls certificate verification. the quickstart now generates private keys that are used when requesting certificates with acme. the private keys are pre-generated because they must be static and known during setup, because their public keys must be published in tlsa records in dns. autocert would generate private keys on its own, so had to be forked to add the option to provide the private key when requesting a new certificate. hopefully upstream will accept the change and we can drop the fork. with this change, using the quickstart to setup a new mox instance, the checks at internet.nl result in a 100% score, provided the domain is dnssec-signed and the network doesn't have any issues.
45 lines
1.7 KiB
Go
45 lines
1.7 KiB
Go
// Copyright 2022 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package adns
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import (
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"os"
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"sync/atomic"
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"time"
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)
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var (
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defaultNS = []string{"127.0.0.1:53", "[::1]:53"}
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getHostname = os.Hostname // variable for testing
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)
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type dnsConfig struct {
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servers []string // server addresses (in host:port form) to use
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search []string // rooted suffixes to append to local name
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ndots int // number of dots in name to trigger absolute lookup
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timeout time.Duration // wait before giving up on a query, including retries
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attempts int // lost packets before giving up on server
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rotate bool // round robin among servers
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unknownOpt bool // anything unknown was encountered
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lookup []string // OpenBSD top-level database "lookup" order
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err error // any error that occurs during open of resolv.conf
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mtime time.Time // time of resolv.conf modification
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soffset uint32 // used by serverOffset
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singleRequest bool // use sequential A and AAAA queries instead of parallel queries
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useTCP bool // force usage of TCP for DNS resolutions
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trustAD bool // add AD flag to queries
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noReload bool // do not check for config file updates
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}
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// serverOffset returns an offset that can be used to determine
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// indices of servers in c.servers when making queries.
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// When the rotate option is enabled, this offset increases.
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// Otherwise it is always 0.
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func (c *dnsConfig) serverOffset() uint32 {
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if c.rotate {
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return atomic.AddUint32(&c.soffset, 1) - 1 // return 0 to start
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}
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return 0
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}
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