mox!

smtpserver/alignment.go

@@ -0,0 +1,42 @@
+package smtpserver
+
+import (
+	"context"
+
+	"github.com/mjl-/mox/dkim"
+	"github.com/mjl-/mox/dns"
+	"github.com/mjl-/mox/publicsuffix"
+	"github.com/mjl-/mox/spf"
+	"github.com/mjl-/mox/store"
+)
+
+// Alignment compares the msgFromDomain with the dkim and spf results, and returns
+// a validation, one of: Strict, Relaxed, None.
+func alignment(ctx context.Context, msgFromDomain dns.Domain, dkimResults []dkim.Result, spfStatus spf.Status, spfIdentity *dns.Domain) store.Validation {
+	var strict, relaxed bool
+	msgFromOrgDomain := publicsuffix.Lookup(ctx, msgFromDomain)
+
+	// todo: should take temperror and permerror into account.
+	for _, dr := range dkimResults {
+		if dr.Status != dkim.StatusPass || dr.Sig == nil {
+			continue
+		}
+		if dr.Sig.Domain == msgFromDomain {
+			strict = true
+			break
+		} else {
+			relaxed = relaxed || msgFromOrgDomain == publicsuffix.Lookup(ctx, dr.Sig.Domain)
+		}
+	}
+	if !strict && spfStatus == spf.StatusPass {
+		strict = msgFromDomain == *spfIdentity
+		relaxed = relaxed || msgFromOrgDomain == publicsuffix.Lookup(ctx, *spfIdentity)
+	}
+	if strict {
+		return store.ValidationStrict
+	}
+	if relaxed {
+		return store.ValidationRelaxed
+	}
+	return store.ValidationNone
+}