httpcaddyfile: Don't add HTTP hosts to TLS APs (fix #4176 and fix #4198)

In the Caddyfile, hosts specified for HTTP sockets (either scheme is "http" or it is on the HTTP port) should not be used as subjects in TLS automation policies (APs).

caddyconfig/httpcaddyfile/directives.go

@@ -478,6 +478,27 @@ func (sb serverBlock) hostsFromKeys(loggerMode bool) []string {
 	return sblockHosts
 }
 
+func (sb serverBlock) hostsFromKeysNotHTTP(httpPort string) []string {
+	// ensure each entry in our list is unique
+	hostMap := make(map[string]struct{})
+	for _, addr := range sb.keys {
+		if addr.Host == "" {
+			continue
+		}
+		if addr.Scheme != "http" && addr.Port != httpPort {
+			hostMap[addr.Host] = struct{}{}
+		}
+	}
+
+	// convert map to slice
+	sblockHosts := make([]string, 0, len(hostMap))
+	for host := range hostMap {
+		sblockHosts = append(sblockHosts, host)
+	}
+
+	return sblockHosts
+}
+
 // hasHostCatchAllKey returns true if sb has a key that
 // omits a host portion, i.e. it "catches all" hosts.
 func (sb serverBlock) hasHostCatchAllKey() bool {

caddyconfig/httpcaddyfile/tlsapp.go

@@ -189,7 +189,7 @@ func (st ServerType) buildTLSApp(
 			}
 
 			// associate our new automation policy with this server block's hosts
-			ap.Subjects = sblockHosts
+			ap.Subjects = sblock.hostsFromKeysNotHTTP(httpPort)
 			sort.Strings(ap.Subjects) // solely for deterministic test results
 
 			// if a combination of public and internal names were given

caddytest/integration/caddyfile_adapt/tls_automation_policies_7.txt

@@ -0,0 +1,68 @@
+# (this Caddyfile is contrived, but based on issues #4176 and #4198)
+
+http://example.com {
+}
+
+https://example.com {
+	tls internal
+}
+
+----------
+{
+	"apps": {
+		"http": {
+			"servers": {
+				"srv0": {
+					"listen": [
+						":443"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"example.com"
+									]
+								}
+							],
+							"terminal": true
+						}
+					]
+				},
+				"srv1": {
+					"listen": [
+						":80"
+					],
+					"routes": [
+						{
+							"match": [
+								{
+									"host": [
+										"example.com"
+									]
+								}
+							],
+							"terminal": true
+						}
+					]
+				}
+			}
+		},
+		"tls": {
+			"automation": {
+				"policies": [
+					{
+						"subjects": [
+							"example.com"
+						],
+						"issuers": [
+							{
+								"module": "internal"
+							}
+						]
+					}
+				]
+			}
+		}
+	}
+}