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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.
115 lines
3.5 KiB
Go
115 lines
3.5 KiB
Go
package adns
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import (
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"fmt"
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)
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// TLSAUsage indicates which certificate/public key verification must be done.
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type TLSAUsage uint8
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const (
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// PKIX/WebPKI, certificate must be valid (name, expiry, signed by CA, etc) and
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// signed by the trusted-anchor (TA) in this record.
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TLSAUsagePKIXTA TLSAUsage = 0
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// PKIX/WebPKI, certificate must be valid (name, expiry, signed by CA, etc) and
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// match the certificate in the record.
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TLSAUsagePKIXEE TLSAUsage = 1
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// Certificate must be signed by trusted-anchor referenced in record, with matching
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// name, non-expired, etc.
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TLSAUsageDANETA TLSAUsage = 2
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// Certificate must match the record. No further requirements on name, expiration
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// or who signed it.
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TLSAUsageDANEEE TLSAUsage = 3
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)
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// String returns the lower-case acronym of a usage, or "(unknown)" for
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// unrecognized values.
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func (u TLSAUsage) String() string {
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switch u {
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case TLSAUsagePKIXTA:
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return "pkix-ta"
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case TLSAUsagePKIXEE:
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return "pkix-ee"
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case TLSAUsageDANETA:
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return "dane-ta"
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case TLSAUsageDANEEE:
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return "dane-ee"
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}
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return "(unknown)"
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}
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// TLSASelecter indicates the data the "certificate association" field is based on.
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type TLSASelector uint8
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const (
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// DER-encoded x509 certificate.
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TLSASelectorCert TLSASelector = 0
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// DER-encoded subject public key info (SPKI), so only the public key and its type.
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TLSASelectorSPKI TLSASelector = 1
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)
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// String returns the lower-case acronym of a selector, or "(unknown)" for
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// unrecognized values.
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func (s TLSASelector) String() string {
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switch s {
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case TLSASelectorCert:
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return "cert"
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case TLSASelectorSPKI:
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return "spki"
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}
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return "(unknown)"
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}
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// TLSAMatchType indicates in which form the data as indicated by the selector
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// is stored in the record as certificate association.
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type TLSAMatchType uint8
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const (
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// Full data, e.g. a full DER-encoded SPKI or even certificate.
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TLSAMatchTypeFull TLSAMatchType = 0
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// SHA2-256-hashed data, either SPKI or certificate.
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TLSAMatchTypeSHA256 TLSAMatchType = 1
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// SHA2-512-hashed data.
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TLSAMatchTypeSHA512 TLSAMatchType = 2
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)
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// String returns the lower-case acronym of a match type, or "(unknown)" for
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// unrecognized values.
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func (mt TLSAMatchType) String() string {
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switch mt {
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case TLSAMatchTypeFull:
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return "full"
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case TLSAMatchTypeSHA256:
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return "sha2-256"
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case TLSAMatchTypeSHA512:
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return "sha2-512"
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}
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return "(unknown)"
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}
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// TLSA represents a TLSA DNS record.
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type TLSA struct {
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Usage TLSAUsage // Which validations must be performed.
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Selector TLSASelector // What needs to be validated (full certificate or only public key).
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MatchType TLSAMatchType // In which form the certificate/public key is stored in CertAssoc.
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CertAssoc []byte // Certificate association data.
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}
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// Record returns a TLSA record value for inclusion in DNS. For example:
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//
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// 3 1 1 133b919c9d65d8b1488157315327334ead8d83372db57465ecabf53ee5748aee
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//
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// A full record in a zone file may look like this:
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//
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// _25._tcp.example.com. IN TLSA 3 1 1 133b919c9d65d8b1488157315327334ead8d83372db57465ecabf53ee5748aee
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//
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// This record is dane-ee (3), spki (1), sha2-256 (1), and the hexadecimal data
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// is the sha2-256 hash.
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func (r TLSA) Record() string {
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return fmt.Sprintf("%d %d %d %x", r.Usage, r.Selector, r.MatchType, r.CertAssoc)
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}
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// String is like Record but prints both the acronym and code for each field.
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func (r TLSA) String() string {
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return fmt.Sprintf("%s(%d) %s(%d) %s(%d) %x", r.Usage, r.Usage, r.Selector, r.Selector, r.MatchType, r.MatchType, r.CertAssoc)
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}
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