Make whitelist optional (#2363)

Author: lauren-mills

lib/csharp/microsoft.bot.builder.skills/Microsoft.Bot.Builder.Skills/Auth/Authenticator.cs

@@ -46,9 +46,9 @@ public async Task<ClaimsIdentity> Authenticate(HttpRequest httpRequest, HttpResp
 
             var appIdClaimName = AuthHelpers.GetAppIdClaimName(claimsIdentity);
             var appId = claimsIdentity.Claims.FirstOrDefault(c => c.Type == appIdClaimName)?.Value;
-            if (_whitelistAuthenticationProvider.AppsWhitelist == null
-                || _whitelistAuthenticationProvider.AppsWhitelist.Count == 0
-                || !_whitelistAuthenticationProvider.AppsWhitelist.Contains(appId))
+            if (_whitelistAuthenticationProvider.AppsWhitelist != null
+                && _whitelistAuthenticationProvider.AppsWhitelist.Count > 0
+                && !_whitelistAuthenticationProvider.AppsWhitelist.Contains(appId))
             {
                 httpResponse.StatusCode = (int)HttpStatusCode.Unauthorized;
                 await httpResponse.WriteAsync("Skill could not allow access from calling bot.").ConfigureAwait(false);

templates/Skill-Template/csharp/Sample/SkillSample/WhiteListAuthProvider.cs

@@ -20,7 +20,7 @@ public WhiteListAuthProvider(IConfiguration configuration)
             // the parent bot's microsoft app id to the list
             var section = configuration.GetSection($"skillAuthenticationWhitelist");
             var appsList = section.Get<string[]>();
-            AppsWhitelist = new HashSet<string>(appsList);
+            AppsWhitelist = appsList != null ? new HashSet<string>(appsList) : null;
         }
 
         public HashSet<string> AppsWhitelist { get; }

templates/Skill-Template/csharp/Template/Skill/WhiteListAuthProvider.cs

@@ -20,7 +20,7 @@ public WhiteListAuthProvider(IConfiguration configuration)
             // the parent bot's microsoft app id to the list
             var section = configuration.GetSection($"skillAuthenticationWhitelist");
             var appsList = section.Get<string[]>();
-            AppsWhitelist = new HashSet<string>(appsList);
+            AppsWhitelist = appsList != null ? new HashSet<string>(appsList) : null;
         }
 
         public HashSet<string> AppsWhitelist { get; }