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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.
119 lines
3 KiB
Go
119 lines
3 KiB
Go
package message
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import (
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"fmt"
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)
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// ../rfc/8601:577
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// Authentication-Results header, see RFC 8601.
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type AuthResults struct {
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Hostname string
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Comment string // If not empty, header comment without "()", added after Hostname.
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Methods []AuthMethod
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}
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// ../rfc/8601:598
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// AuthMethod is a result for one authentication method.
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//
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// Example encoding in the header: "spf=pass smtp.mailfrom=example.net".
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type AuthMethod struct {
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// E.g. "dkim", "spf", "iprev", "auth".
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Method string
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Result string // Each method has a set of known values, e.g. "pass", "temperror", etc.
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Comment string // Optional, message header comment.
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Reason string // Optional.
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Props []AuthProp
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}
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// ../rfc/8601:606
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// AuthProp describes properties for an authentication method.
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// Each method has a set of known properties.
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// Encoded in the header as "type.property=value", e.g. "smtp.mailfrom=example.net"
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// for spf.
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type AuthProp struct {
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// Valid values maintained at https://www.iana.org/assignments/email-auth/email-auth.xhtml
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Type string
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Property string
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Value string
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// Whether value is address-like (localpart@domain, or domain). Or another value,
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// which is subject to escaping.
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IsAddrLike bool
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Comment string // If not empty, header comment without "()", added after Value.
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}
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// MakeAuthProp is a convenient way to make an AuthProp.
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func MakeAuthProp(typ, property, value string, isAddrLike bool, Comment string) AuthProp {
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return AuthProp{typ, property, value, isAddrLike, Comment}
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}
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// todo future: we could store fields as dns.Domain, and when we encode as non-ascii also add the ascii version as a comment.
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// Header returns an Authentication-Results header, possibly spanning multiple
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// lines, always ending in crlf.
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func (h AuthResults) Header() string {
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// Escaping of values: ../rfc/8601:684 ../rfc/2045:661
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optComment := func(s string) string {
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if s != "" {
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return " (" + s + ")"
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}
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return s
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}
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w := &HeaderWriter{}
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w.Add("", "Authentication-Results:"+optComment(h.Comment)+" "+value(h.Hostname)+";")
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for i, m := range h.Methods {
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tokens := []string{}
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addf := func(format string, args ...any) {
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s := fmt.Sprintf(format, args...)
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tokens = append(tokens, s)
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}
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addf("%s=%s", m.Method, m.Result)
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if m.Comment != "" && (m.Reason != "" || len(m.Props) > 0) {
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addf("(%s)", m.Comment)
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}
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if m.Reason != "" {
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addf("reason=%s", value(m.Reason))
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}
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for _, p := range m.Props {
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v := p.Value
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if !p.IsAddrLike {
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v = value(v)
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}
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addf("%s.%s=%s%s", p.Type, p.Property, v, optComment(p.Comment))
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}
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for j, t := range tokens {
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if j == len(tokens)-1 && i < len(h.Methods)-1 {
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t += ";"
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}
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w.Add(" ", t)
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}
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}
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return w.String()
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}
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func value(s string) string {
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quote := s == ""
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for _, c := range s {
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// utf-8 does not have to be quoted. ../rfc/6532:242
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if c == '"' || c == '\\' || c <= ' ' || c == 0x7f {
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quote = true
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break
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}
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}
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if !quote {
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return s
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}
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r := `"`
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for _, c := range s {
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if c == '"' || c == '\\' {
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r += "\\"
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}
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r += string(c)
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}
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r += `"`
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return r
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}
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