Basic HTTP Auth (#163).

server/handler/handler.go

@@ -25,12 +25,26 @@ func Handler(mainDomainSuffix, rawDomain string,
 	giteaClient *gitea.Client,
 	rawInfoPage string,
 	blacklistedPaths, allowedCorsDomains []string,
-	dnsLookupCache, canonicalDomainCache cache.SetGetKey,
+	dnsLookupCache, canonicalDomainCache, authCache cache.SetGetKey,
 ) http.HandlerFunc {
 	return func(w http.ResponseWriter, req *http.Request) {
 		log := log.With().Strs("Handler", []string{req.Host, req.RequestURI}).Logger()
 		ctx := context.New(w, req)
 
+		trimmedHost := ctx.TrimHostPort()
+
+		credentials := handleAuth(log, ctx, giteaClient,
+			mainDomainSuffix,
+			trimmedHost,
+			dnsLookupCache, authCache)
+
+		if len(credentials) > 0 {
+			authenticated := enforceBasicHTTPAuth(credentials, w, req)
+			if !authenticated {
+				return
+			}
+		}
+
 		ctx.RespWriter.Header().Set("Server", "CodebergPages/"+version.Version)
 
 		// Force new default from specification (since November 2020) - see https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Referrer-Policy#strict-origin-when-cross-origin
@@ -39,8 +53,6 @@ func Handler(mainDomainSuffix, rawDomain string,
 		// Enable browser caching for up to 10 minutes
 		ctx.RespWriter.Header().Set("Cache-Control", "public, max-age=600")
 
-		trimmedHost := ctx.TrimHostPort()
-
 		// Add HSTS for RawDomain and MainDomainSuffix
 		if hsts := getHSTSHeader(trimmedHost, mainDomainSuffix, rawDomain); hsts != "" {
 			ctx.RespWriter.Header().Set("Strict-Transport-Security", hsts)
@@ -109,5 +121,44 @@ func Handler(mainDomainSuffix, rawDomain string,
 				pathElements,
 				dnsLookupCache, canonicalDomainCache)
 		}
+
 	}
 }
+
+func enforceBasicHTTPAuth(credentials []string, w http.ResponseWriter, req *http.Request) bool {
+	authorizedUsers := getAuthorizedUsers(credentials)
+	username, password, ok := req.BasicAuth()
+	if !ok {
+		w.Header().Add("WWW-Authenticate", `Basic realm="Give username and password"`)
+		w.WriteHeader(http.StatusUnauthorized)
+		w.Write([]byte(`{"message": "No basic auth present"}`))
+		return false
+	}
+	if !isAuthorized(username, password, authorizedUsers) {
+		w.Header().Add("WWW-Authenticate", `Basic realm="Give username and password"`)
+		w.WriteHeader(http.StatusUnauthorized)
+		w.Write([]byte(`{"message": "Invalid username or password"}`))
+		return false
+	}
+	return true
+}
+
+func getAuthorizedUsers(credentials []string) map[string]string {
+	authorizedUsers := make(map[string]string)
+	for _, authLine := range credentials {
+		authLineParts := strings.Split(authLine, ",")
+		user := strings.TrimSpace(authLineParts[0])
+		password := strings.TrimSpace(authLineParts[1])
+		authorizedUsers[user] = password
+	}
+	return authorizedUsers
+
+}
+
+func isAuthorized(username, password string, credentials map[string]string) bool {
+	pass, ok := credentials[username]
+	if !ok {
+		return false
+	}
+	return password == pass
+}