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improvements to outgoing dmarc reports and displaying evaluations
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- more eagerly report about overrides, so domain owners can better tell that
  switching from p=none to p=reject will not cause trouble for these messages.
- report multiple reasons, e.g. mailing list and sampled out
- in dmarc analysis for rejects from first-time senders (possibly spammers),
  fix the conditional check on nonjunk messages.
- in evaluations view in admin, show unaligned spf pass in yellow too and a few
  more small tweaks.
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mjl- committed Nov 2, 2023
1 parent 79e5228 commit 481a25f
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Showing 2 changed files with 19 additions and 18 deletions.
29 changes: 15 additions & 14 deletions smtpserver/server.go
Original file line number Diff line number Diff line change
Expand Up @@ -2411,24 +2411,26 @@ func (c *conn) deliver(ctx context.Context, recvHdrFor func(string) string, msgW

// Any DMARC result override is stored in the evaluation for outgoing DMARC
// aggregate reports, and added to the Authentication-Results message header.
var dmarcOverride string
if dmarcResult.Record != nil {
if !dmarcUse {
dmarcOverride = string(dmarcrpt.PolicyOverrideSampledOut)
} else if a.dmarcOverrideReason != "" && (a.accept && !m.IsReject) == dmarcResult.Reject {
dmarcOverride = a.dmarcOverrideReason
}
// We want to tell the sender that we have an override, e.g. for mailing lists, so
// they don't overestimate the potential damage of switching from p=none to
// p=reject.
var dmarcOverrides []string
if a.dmarcOverrideReason != "" {
dmarcOverrides = []string{a.dmarcOverrideReason}
}
if dmarcResult.Record != nil && !dmarcUse {
dmarcOverrides = append(dmarcOverrides, string(dmarcrpt.PolicyOverrideSampledOut))
}

// Add per-recipient DMARC method to Authentication-Results. Each account can have
// their own override rules, e.g. based on configured mailing lists/forwards.
// ../rfc/7489:1486
rcptDMARCMethod := dmarcMethod
if dmarcOverride != "" {
if len(dmarcOverrides) > 0 {
if rcptDMARCMethod.Comment != "" {
rcptDMARCMethod.Comment += ", "
}
rcptDMARCMethod.Comment += "override " + dmarcOverride
rcptDMARCMethod.Comment += "override " + strings.Join(dmarcOverrides, ",")
}
rcptAuthResults := authResults
rcptAuthResults.Methods = append([]message.AuthMethod{}, authResults.Methods...)
Expand Down Expand Up @@ -2477,7 +2479,7 @@ func (c *conn) deliver(ctx context.Context, recvHdrFor func(string) string, msgW
// See if we received a non-junk message from this organizational domain.
q := bstore.QueryTx[store.Message](tx)
q.FilterNonzero(store.Message{MsgFromOrgDomain: m.MsgFromOrgDomain})
q.FilterEqual("Notjunk", false)
q.FilterEqual("Notjunk", true)
exists, err := q.Exists()
if err != nil {
return fmt.Errorf("querying for non-junk message from organizational domain: %v", err)
Expand Down Expand Up @@ -2544,10 +2546,9 @@ func (c *conn) deliver(ctx context.Context, recvHdrFor func(string) string, msgW
HeaderFrom: msgFrom.Domain.Name(),
}

if dmarcOverride != "" {
eval.OverrideReasons = []dmarcrpt.PolicyOverrideReason{
{Type: dmarcrpt.PolicyOverride(dmarcOverride)},
}
for _, s := range dmarcOverrides {
reason := dmarcrpt.PolicyOverrideReason{Type: dmarcrpt.PolicyOverride(s)}
eval.OverrideReasons = append(eval.OverrideReasons, reason)
}

// We'll include all signatures for the organizational domain, even if they weren't
Expand Down
8 changes: 4 additions & 4 deletions webadmin/admin.html
Original file line number Diff line number Diff line change
Expand Up @@ -1148,7 +1148,7 @@

const authStatus = (v) => inlineBox(v ? '' : yellow, v ? 'pass' : 'fail')
const formatDKIMResults = (results) => results.map(r => dom.div('selector '+r.Selector+(r.Domain !== domain ? ', domain '+r.Domain : '') + ': ', inlineBox(r.Result === "pass" ? '' : yellow, r.Result)))
const formatSPFResults = (results) => results.map(r => dom.div(''+r.Scope+(r.Domain !== domain ? ', domain '+r.Domain : '') + ': ', inlineBox(r.Result === "pass" ? '' : yellow, r.Result)))
const formatSPFResults = (alignedpass, results) => results.map(r => dom.div(''+r.Scope+(r.Domain !== domain ? ', domain '+r.Domain : '') + ': ', inlineBox(r.Result === "pass" && alignedpass ? '' : yellow, r.Result)))

const sourceIP = (ip) => {
const r = dom.span(ip, attr({title: 'Click to do a reverse lookup of the IP.'}), style({cursor: 'pointer'}), async function click(e) {
Expand Down Expand Up @@ -1198,7 +1198,7 @@
dom.th('Policy', attr({title: 'Summary of the policy as encountered in the DMARC DNS record of the domain, and used for evaluation.'})),
dom.th('IP', attr({title: 'IP address of delivery attempt that was evaluated, relevant for SPF.'})),
dom.th('Disposition', attr({title: 'Our decision to accept/reject this message. It may be different than requested by the published policy. For example, when overriding due to delivery from a mailing list or forwarded address.'})),
dom.th('DKIM/SPF', attr({title: 'Whether DKIM and SPF had an aligned pass, where strict/relaxed alignment means whether the domain of an SPF pass and DKIM pass matches the exact domain (strict) or optionally a subdomain (relaxed). A DMARC pass requires at least one pass.'})),
dom.th('Aligned DKIM/SPF', attr({title: 'Whether DKIM and SPF had an aligned pass, where strict/relaxed alignment means whether the domain of an SPF pass and DKIM pass matches the exact domain (strict) or optionally a subdomain (relaxed). A DMARC pass requires at least one pass.'})),
dom.th('Envelope to', attr({title: 'Domain used in SMTP RCPT TO during delivery.'})),
dom.th('Envelope from', attr({title: 'Domain used in SMTP MAIL FROM during delivery.'})),
dom.th('Message from', attr({title: 'Domain in "From" message header.'})),
Expand Down Expand Up @@ -1228,13 +1228,13 @@
dom.td(addresses),
dom.td(policy),
dom.td(sourceIP(e.SourceIP)),
dom.td(inlineBox(e.Disposition === 'none' ? '' : 'red', e.Disposition), (e.OverrideReasons || []).length > 0 ? ' ('+e.OverrideReasons.map(r => r.Type).join(', ')+')' : ''),
dom.td(inlineBox(e.Disposition === 'none' ? '' : red, e.Disposition), (e.OverrideReasons || []).length > 0 ? ' ('+e.OverrideReasons.map(r => r.Type).join(', ')+')' : ''),
dom.td(authStatus(e.AlignedDKIMPass), '/', authStatus(e.AlignedSPFPass)),
dom.td(e.EnvelopeTo),
dom.td(e.EnvelopeFrom),
dom.td(e.HeaderFrom),
dom.td(formatDKIMResults(e.DKIMResults || [])),
dom.td(formatSPFResults(e.SPFResults || [])),
dom.td(formatSPFResults(e.AlignedSPFPass, e.SPFResults || [])),
)
}),
evaluations.length === 0 ? dom.tr(dom.td(attr({colspan: '14'}), 'No evaluations.')) : [],
Expand Down

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