autohttps: Implement auto_https prefer_wildcard option

caddyconfig/httpcaddyfile/httptype.go

@@ -520,8 +520,8 @@ func (st *ServerType) serversFromPairings(
 	if hsp, ok := options["https_port"].(int); ok {
 		httpsPort = strconv.Itoa(hsp)
 	}
-	autoHTTPS := "on"
-	if ah, ok := options["auto_https"].(string); ok {
+	autoHTTPS := []string{}
+	if ah, ok := options["auto_https"].([]string); ok {
 		autoHTTPS = ah
 	}
 
@@ -548,17 +548,37 @@ func (st *ServerType) serversFromPairings(
 		}
 
 		// handle the auto_https global option
-		if autoHTTPS != "on" {
-			srv.AutoHTTPS = new(caddyhttp.AutoHTTPSConfig)
-			switch autoHTTPS {
+		for _, val := range autoHTTPS {
+			switch val {
 			case "off":
+				if srv.AutoHTTPS == nil {
+					srv.AutoHTTPS = new(caddyhttp.AutoHTTPSConfig)
+				}
 				srv.AutoHTTPS.Disabled = true
+
 			case "disable_redirects":
+				if srv.AutoHTTPS == nil {
+					srv.AutoHTTPS = new(caddyhttp.AutoHTTPSConfig)
+				}
 				srv.AutoHTTPS.DisableRedir = true
+
 			case "disable_certs":
+				if srv.AutoHTTPS == nil {
+					srv.AutoHTTPS = new(caddyhttp.AutoHTTPSConfig)
+				}
 				srv.AutoHTTPS.DisableCerts = true
+
 			case "ignore_loaded_certs":
+				if srv.AutoHTTPS == nil {
+					srv.AutoHTTPS = new(caddyhttp.AutoHTTPSConfig)
+				}
 				srv.AutoHTTPS.IgnoreLoadedCerts = true
+
+			case "prefer_wildcard":
+				if srv.AutoHTTPS == nil {
+					srv.AutoHTTPS = new(caddyhttp.AutoHTTPSConfig)
+				}
+				srv.AutoHTTPS.PreferWildcard = true
 			}
 		}
 
@@ -627,7 +647,7 @@ func (st *ServerType) serversFromPairings(
 		})
 
 		var hasCatchAllTLSConnPolicy, addressQualifiesForTLS bool
-		autoHTTPSWillAddConnPolicy := autoHTTPS != "off"
+		autoHTTPSWillAddConnPolicy := srv.AutoHTTPS == nil || !srv.AutoHTTPS.Disabled
 
 		// if needed, the ServerLogConfig is initialized beforehand so
 		// that all server blocks can populate it with data, even when not
@@ -711,6 +731,13 @@ func (st *ServerType) serversFromPairings(
 				}
 			}
 
+			wildcardHosts := []string{}
+			for _, addr := range sblock.keys {
+				if strings.HasPrefix(addr.Host, "*.") {
+					wildcardHosts = append(wildcardHosts, addr.Host[2:])
+				}
+			}
+
 			for _, addr := range sblock.keys {
 				// if server only uses HTTP port, auto-HTTPS will not apply
 				if listenersUseAnyPortOtherThan(srv.Listen, httpPort) {
@@ -726,6 +753,18 @@ func (st *ServerType) serversFromPairings(
 					}
 				}
 
+				// If prefer wildcard is enabled, then we add hosts that are
+				// already covered by the wildcard to the skip list
+				if srv.AutoHTTPS != nil && srv.AutoHTTPS.PreferWildcard && addr.Scheme == "https" {
+					baseDomain := addr.Host
+					if idx := strings.Index(baseDomain, "."); idx != -1 {
+						baseDomain = baseDomain[idx+1:]
+					}
+					if !strings.HasPrefix(addr.Host, "*.") && sliceContains(wildcardHosts, baseDomain) {
+						srv.AutoHTTPS.Skip = append(srv.AutoHTTPS.Skip, addr.Host)
+					}
+				}
+
 				// If TLS is specified as directive, it will also result in 1 or more connection policy being created
 				// Thus, catch-all address with non-standard port, e.g. :8443, can have TLS enabled without
 				// specifying prefix "https://"
@@ -873,7 +912,10 @@ func (st *ServerType) serversFromPairings(
 		if addressQualifiesForTLS &&
 			!hasCatchAllTLSConnPolicy &&
 			(len(srv.TLSConnPolicies) > 0 || !autoHTTPSWillAddConnPolicy || defaultSNI != "" || fallbackSNI != "") {
-			srv.TLSConnPolicies = append(srv.TLSConnPolicies, &caddytls.ConnectionPolicy{DefaultSNI: defaultSNI, FallbackSNI: fallbackSNI})
+			srv.TLSConnPolicies = append(srv.TLSConnPolicies, &caddytls.ConnectionPolicy{
+				DefaultSNI:  defaultSNI,
+				FallbackSNI: fallbackSNI,
+			})
 		}
 
 		// tidy things up a bit

caddyconfig/httpcaddyfile/options.go

@@ -433,15 +433,22 @@ func parseOptPersistConfig(d *caddyfile.Dispenser, _ any) (any, error) {
 
 func parseOptAutoHTTPS(d *caddyfile.Dispenser, _ any) (any, error) {
 	d.Next() // consume option name
-	if !d.Next() {
-		return "", d.ArgErr()
-	}
-	val := d.Val()
-	if d.Next() {
+	val := d.RemainingArgs()
+	if len(val) == 0 {
 		return "", d.ArgErr()
 	}
-	if val != "off" && val != "disable_redirects" && val != "disable_certs" && val != "ignore_loaded_certs" {
-		return "", d.Errf("auto_https must be one of 'off', 'disable_redirects', 'disable_certs', or 'ignore_loaded_certs'")
+	for _, v := range val {
+		switch v {
+		case "off":
+		case "disable_redirects":
+		case "disable_certs":
+		case "ignore_loaded_certs":
+		case "prefer_wildcard":
+			break
+
+		default:
+			return "", d.Errf("auto_https must be one of 'off', 'disable_redirects', 'disable_certs', 'ignore_loaded_certs', or 'prefer_wildcard'")
+		}
 	}
 	return val, nil
 }

caddyconfig/httpcaddyfile/tlsapp.go

@@ -44,32 +44,34 @@ func (st ServerType) buildTLSApp(
 	if hp, ok := options["http_port"].(int); ok {
 		httpPort = strconv.Itoa(hp)
 	}
-	autoHTTPS := "on"
-	if ah, ok := options["auto_https"].(string); ok {
+	autoHTTPS := []string{}
+	if ah, ok := options["auto_https"].([]string); ok {
 		autoHTTPS = ah
 	}
 
 	// find all hosts that share a server block with a hostless
 	// key, so that they don't get forgotten/omitted by auto-HTTPS
 	// (since they won't appear in route matchers)
 	httpsHostsSharedWithHostlessKey := make(map[string]struct{})
-	if autoHTTPS != "off" {
+	if !sliceContains(autoHTTPS, "off") {
 		for _, pair := range pairings {
 			for _, sb := range pair.serverBlocks {
 				for _, addr := range sb.keys {
-					if addr.Host == "" {
-						// this server block has a hostless key, now
-						// go through and add all the hosts to the set
-						for _, otherAddr := range sb.keys {
-							if otherAddr.Original == addr.Original {
-								continue
-							}
-							if otherAddr.Host != "" && otherAddr.Scheme != "http" && otherAddr.Port != httpPort {
-								httpsHostsSharedWithHostlessKey[otherAddr.Host] = struct{}{}
-							}
+					if addr.Host != "" {
+						continue
+					}
+
+					// this server block has a hostless key, now
+					// go through and add all the hosts to the set
+					for _, otherAddr := range sb.keys {
+						if otherAddr.Original == addr.Original {
+							continue
+						}
+						if otherAddr.Host != "" && otherAddr.Scheme != "http" && otherAddr.Port != httpPort {
+							httpsHostsSharedWithHostlessKey[otherAddr.Host] = struct{}{}
 						}
-						break
 					}
+					break
 				}
 			}
 		}
@@ -344,7 +346,7 @@ func (st ServerType) buildTLSApp(
 	internalAP := &caddytls.AutomationPolicy{
 		IssuersRaw: []json.RawMessage{json.RawMessage(`{"module":"internal"}`)},
 	}
-	if autoHTTPS != "off" && autoHTTPS != "disable_certs" {
+	if !sliceContains(autoHTTPS, "off") && !sliceContains(autoHTTPS, "disable_certs") {
 		for h := range httpsHostsSharedWithHostlessKey {
 			al = append(al, h)
 			if !certmagic.SubjectQualifiesForPublicCert(h) {
@@ -411,7 +413,10 @@ func (st ServerType) buildTLSApp(
 		}
 
 		// consolidate automation policies that are the exact same
-		tlsApp.Automation.Policies = consolidateAutomationPolicies(tlsApp.Automation.Policies)
+		tlsApp.Automation.Policies = consolidateAutomationPolicies(
+			tlsApp.Automation.Policies,
+			sliceContains(autoHTTPS, "prefer_wildcard"),
+		)
 
 		// ensure automation policies don't overlap subjects (this should be
 		// an error at provision-time as well, but catch it in the adapt phase
@@ -539,7 +544,7 @@ func newBaseAutomationPolicy(
 
 // consolidateAutomationPolicies combines automation policies that are the same,
 // for a cleaner overall output.
-func consolidateAutomationPolicies(aps []*caddytls.AutomationPolicy) []*caddytls.AutomationPolicy {
+func consolidateAutomationPolicies(aps []*caddytls.AutomationPolicy, preferWildcard bool) []*caddytls.AutomationPolicy {
 	// sort from most specific to least specific; we depend on this ordering
 	sort.SliceStable(aps, func(i, j int) bool {
 		if automationPolicyIsSubset(aps[i], aps[j]) {
@@ -624,6 +629,31 @@ outer:
 					j--
 				}
 			}
+
+			if preferWildcard {
+				// remove subjects from i if they're covered by a wildcard in j
+				iSubjs := aps[i].SubjectsRaw
+				for iSubj := 0; iSubj < len(iSubjs); iSubj++ {
+					for jSubj := range aps[j].SubjectsRaw {
+						if !strings.HasPrefix(aps[j].SubjectsRaw[jSubj], "*.") {
+							continue
+						}
+						if certmagic.MatchWildcard(aps[i].SubjectsRaw[iSubj], aps[j].SubjectsRaw[jSubj]) {
+							iSubjs = append(iSubjs[:iSubj], iSubjs[iSubj+1:]...)
+							iSubj--
+							break
+						}
+					}
+				}
+				aps[i].SubjectsRaw = iSubjs
+
+				// remove i if it has no subjects left
+				if len(aps[i].SubjectsRaw) == 0 {
+					aps = append(aps[:i], aps[i+1:]...)
+					i--
+					continue outer
+				}
+			}
 		}
 	}
 

modules/caddyhttp/autohttps.go

@@ -64,6 +64,12 @@ type AutoHTTPSConfig struct {
 	// enabled. To force automated certificate management
 	// regardless of loaded certificates, set this to true.
 	IgnoreLoadedCerts bool `json:"ignore_loaded_certificates,omitempty"`
+
+	// If true, automatic HTTPS will prefer wildcard names
+	// and ignore non-wildcard names if both are available.
+	// This allows for writing a config with top-level host
+	// matchers without having those names produce certificates.
+	PreferWildcard bool `json:"prefer_wildcard,omitempty"`
 }
 
 // Skipped returns true if name is in skipSlice, which
@@ -167,6 +173,27 @@ func (app *App) automaticHTTPSPhase1(ctx caddy.Context, repl *caddy.Replacer) er
 			}
 		}
 
+		if srv.AutoHTTPS.PreferWildcard {
+			wildcards := make(map[string]struct{})
+			for d := range serverDomainSet {
+				if strings.HasPrefix(d, "*.") {
+					wildcards[d[2:]] = struct{}{}
+				}
+			}
+			for d := range serverDomainSet {
+				if strings.HasPrefix(d, "*.") {
+					continue
+				}
+				base := d
+				if idx := strings.Index(d, "."); idx != -1 {
+					base = d[idx+1:]
+				}
+				if _, ok := wildcards[base]; ok {
+					delete(serverDomainSet, d)
+				}
+			}
+		}
+
 		// nothing more to do here if there are no domains that qualify for
 		// automatic HTTPS and there are no explicit TLS connection policies:
 		// if there is at least one domain but no TLS conn policy (F&&T), we'll