Accept a captcha score threshold for challenges from the spam filter

service/src/main/java/org/whispersystems/textsecuregcm/WhisperServerService.java

@@ -167,6 +167,7 @@ import org.whispersystems.textsecuregcm.s3.PostPolicyGenerator;
 import org.whispersystems.textsecuregcm.securestorage.SecureStorageClient;
 import org.whispersystems.textsecuregcm.securevaluerecovery.SecureValueRecovery2Client;
 import org.whispersystems.textsecuregcm.spam.FilterSpam;
+import org.whispersystems.textsecuregcm.spam.PushChallengeConfigProvider;
 import org.whispersystems.textsecuregcm.spam.RateLimitChallengeListener;
 import org.whispersystems.textsecuregcm.spam.ReportSpamTokenProvider;
 import org.whispersystems.textsecuregcm.spam.ScoreThresholdProvider;
@@ -848,9 +849,14 @@ public class WhisperServerService extends Application<WhisperServerConfiguration
   private void registerProviders(Environment environment,
       WebSocketEnvironment<AuthenticatedAccount> webSocketEnvironment,
       WebSocketEnvironment<AuthenticatedAccount> provisioningEnvironment) {
-    environment.jersey().register(ScoreThresholdProvider.ScoreThresholdFeature.class);
+    List.of(
-    webSocketEnvironment.jersey().register(ScoreThresholdProvider.ScoreThresholdFeature.class);
+        ScoreThresholdProvider.ScoreThresholdFeature.class,
-    provisioningEnvironment.jersey().register(ScoreThresholdProvider.ScoreThresholdFeature.class);
+        PushChallengeConfigProvider.PushChallengeConfigFeature.class)
+    .forEach(feature -> {
+          environment.jersey().register(feature);
+          webSocketEnvironment.jersey().register(feature);
+          provisioningEnvironment.jersey().register(feature);
+    });
   }
 
   private void registerExceptionMappers(Environment environment,

service/src/main/java/org/whispersystems/textsecuregcm/controllers/ChallengeController.java

@@ -36,10 +36,15 @@ import org.whispersystems.textsecuregcm.entities.AnswerRecaptchaChallengeRequest
 import org.whispersystems.textsecuregcm.limits.RateLimitChallengeManager;
 import org.whispersystems.textsecuregcm.metrics.UserAgentTagUtil;
 import org.whispersystems.textsecuregcm.push.NotPushRegisteredException;
+import org.whispersystems.textsecuregcm.spam.Extract;
+import org.whispersystems.textsecuregcm.spam.FilterSpam;
+import org.whispersystems.textsecuregcm.spam.PushChallengeConfig;
+import org.whispersystems.textsecuregcm.spam.ScoreThreshold;
 import org.whispersystems.textsecuregcm.util.HeaderUtils;
 
 @Path("/v1/challenge")
 @Tag(name = "Challenge")
+@FilterSpam
 public class ChallengeController {
 
   private final RateLimitChallengeManager rateLimitChallengeManager;
@@ -74,7 +79,9 @@ public class ChallengeController {
   public Response handleChallengeResponse(@Auth final AuthenticatedAccount auth,
       @Valid final AnswerChallengeRequest answerRequest,
       @HeaderParam(HttpHeaders.X_FORWARDED_FOR) final String forwardedFor,
-      @HeaderParam(HttpHeaders.USER_AGENT) final String userAgent) throws RateLimitExceededException, IOException {
+      @HeaderParam(HttpHeaders.USER_AGENT) final String userAgent,
+      @Extract final ScoreThreshold captchaScoreThreshold,
+      @Extract final PushChallengeConfig pushChallengeConfig) throws RateLimitExceededException, IOException {
 
     Tags tags = Tags.of(UserAgentTagUtil.getPlatformTag(userAgent));
 
@@ -82,6 +89,9 @@ public class ChallengeController {
       if (answerRequest instanceof final AnswerPushChallengeRequest pushChallengeRequest) {
         tags = tags.and(CHALLENGE_TYPE_TAG, "push");
 
+        if (!pushChallengeConfig.pushPermitted()) {
+          return Response.status(429).build();
+        }
         rateLimitChallengeManager.answerPushChallenge(auth.getAccount(), pushChallengeRequest.getChallenge());
       } else if (answerRequest instanceof AnswerRecaptchaChallengeRequest recaptchaChallengeRequest) {
         tags = tags.and(CHALLENGE_TYPE_TAG, "recaptcha");
@@ -91,7 +101,8 @@ public class ChallengeController {
             auth.getAccount(),
             recaptchaChallengeRequest.getCaptcha(),
             mostRecentProxy,
-            userAgent);
+            userAgent,
+            captchaScoreThreshold.getScoreThreshold());
 
         if (!success) {
           return Response.status(428).build();
@@ -150,7 +161,11 @@ public class ChallengeController {
   @ApiResponse(responseCode = "429", description = "Too many attempts", headers = @Header(
       name = "Retry-After",
       description = "If present, an positive integer indicating the number of seconds before a subsequent attempt could succeed"))
-  public Response requestPushChallenge(@Auth final AuthenticatedAccount auth) {
+  public Response requestPushChallenge(@Auth final AuthenticatedAccount auth,
+      @Extract PushChallengeConfig pushChallengeConfig) {
+    if (!pushChallengeConfig.pushPermitted()) {
+      return Response.status(429).build();
+    }
     try {
       rateLimitChallengeManager.sendPushChallenge(auth.getAccount());
       return Response.status(200).build();

service/src/main/java/org/whispersystems/textsecuregcm/limits/RateLimitChallengeManager.java

@@ -14,6 +14,8 @@ import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
+
 import org.whispersystems.textsecuregcm.captcha.Action;
 import org.whispersystems.textsecuregcm.captcha.CaptchaChecker;
 import org.whispersystems.textsecuregcm.controllers.RateLimitExceededException;
@@ -64,12 +66,12 @@ public class RateLimitChallengeManager {
     }
   }
 
-  public boolean answerRecaptchaChallenge(final Account account, final String captcha, final String mostRecentProxyIp, final String userAgent)
+  public boolean answerRecaptchaChallenge(final Account account, final String captcha, final String mostRecentProxyIp, final String userAgent, final Optional<Float> scoreThreshold)
       throws RateLimitExceededException, IOException {
 
     rateLimiters.getRecaptchaChallengeAttemptLimiter().validate(account.getUuid());
 
-    final boolean challengeSuccess = captchaChecker.verify(Action.CHALLENGE, captcha, mostRecentProxyIp).isValid();
+    final boolean challengeSuccess = captchaChecker.verify(Action.CHALLENGE, captcha, mostRecentProxyIp).isValid(scoreThreshold);
 
     final Tags tags = Tags.of(
         Tag.of(SOURCE_COUNTRY_TAG_NAME, Util.getCountryCode(account.getNumber())),

service/src/main/java/org/whispersystems/textsecuregcm/spam/PushChallengeConfig.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.spam;
+
+import java.util.Optional;
+
+import org.glassfish.jersey.server.ContainerRequest;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * A PushChallengeConfig may be provided by an upstream request filter. If request contains a
+ * property for PROPERTY_NAME it can be forwarded to a downstream filter to indicate whether
+ * push-token challenges can be used in place of captchas when evaluating whether a request should
+ * be allowed to continue.
+ */
+public class PushChallengeConfig {
+  private static final Logger logger = LoggerFactory.getLogger(PushChallengeConfig.class);
+
+  public static final String PROPERTY_NAME = "pushChallengePermitted";
+
+  /**
+   * A score threshold in the range [0, 1.0]
+   */
+  private final boolean pushPermitted;
+
+  /**
+   * Extract an optional score threshold parameter provided by an upstream request filter
+   */
+  public PushChallengeConfig(final ContainerRequest containerRequest) {
+    this.pushPermitted = Optional
+        .ofNullable(containerRequest.getProperty(PROPERTY_NAME))
+        .filter(obj -> obj instanceof Boolean)
+        .map(obj -> (Boolean) obj)
+        .orElse(true);          // not a typo! true is the default
+  }
+
+  public boolean pushPermitted() {
+    return pushPermitted;
+  }
+}

service/src/main/java/org/whispersystems/textsecuregcm/spam/PushChallengeConfigProvider.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.spam;
+
+import java.util.function.Function;
+import javax.inject.Singleton;
+import javax.ws.rs.core.Feature;
+import javax.ws.rs.core.FeatureContext;
+import org.glassfish.jersey.internal.inject.AbstractBinder;
+import org.glassfish.jersey.server.ContainerRequest;
+import org.glassfish.jersey.server.model.Parameter;
+import org.glassfish.jersey.server.spi.internal.ValueParamProvider;
+
+/**
+ * Parses a {@link PushChallengeConfig} out of a {@link ContainerRequest} to provide to jersey resources.
+ *
+ * A request filter may enrich a ContainerRequest with a PushChallengeConfig by providing a float
+ * property with the name {@link PushChallengeConfig#PROPERTY_NAME}. This indicates whether push
+ * challenges may be considered when evaluating whether a request should proceed.
+ *
+ * A resource can consume a PushChallengeConfig with by annotating a PushChallengeConfig parameter with {@link Extract}
+ */
+public class PushChallengeConfigProvider implements ValueParamProvider {
+
+  /**
+   * Configures the PushChallengeConfigProvider
+   */
+  public static class PushChallengeConfigFeature implements Feature {
+    @Override
+    public boolean configure(FeatureContext context) {
+      context.register(new AbstractBinder() {
+        @Override
+        protected void configure() {
+          bind(PushChallengeConfigProvider.class)
+              .to(ValueParamProvider.class)
+              .in(Singleton.class);
+        }
+      });
+      return true;
+    }
+  }
+
+  @Override
+  public Function<ContainerRequest, ?> getValueProvider(final Parameter parameter) {
+    if (parameter.getRawType().equals(PushChallengeConfig.class)
+        && parameter.isAnnotationPresent(Extract.class)) {
+      return PushChallengeConfig::new;
+    }
+    return null;
+
+  }
+
+  @Override
+  public PriorityType getPriority() {
+    return Priority.HIGH;
+  }
+}

service/src/test/java/org/whispersystems/textsecuregcm/controllers/ChallengeControllerTest.java

@@ -22,18 +22,29 @@ import io.dropwizard.testing.junit5.DropwizardExtensionsSupport;
 import io.dropwizard.testing.junit5.ResourceExtension;
 import java.io.IOException;
 import java.time.Duration;
+import java.util.Optional;
 import java.util.Set;
+import java.util.concurrent.atomic.AtomicReference;
 import javax.ws.rs.client.Entity;
+import javax.ws.rs.container.ContainerRequestContext;
+import javax.ws.rs.container.ContainerRequestFilter;
+import javax.ws.rs.core.Feature;
+import javax.ws.rs.core.FeatureContext;
 import javax.ws.rs.core.Response;
 import org.glassfish.jersey.test.grizzly.GrizzlyWebTestContainerFactory;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.ValueSource;
 import org.whispersystems.textsecuregcm.auth.AuthenticatedAccount;
 import org.whispersystems.textsecuregcm.auth.DisabledPermittedAuthenticatedAccount;
 import org.whispersystems.textsecuregcm.limits.RateLimitChallengeManager;
 import org.whispersystems.textsecuregcm.mappers.RateLimitExceededExceptionMapper;
 import org.whispersystems.textsecuregcm.push.NotPushRegisteredException;
+import org.whispersystems.textsecuregcm.spam.PushChallengeConfigProvider;
+import org.whispersystems.textsecuregcm.spam.ScoreThreshold;
+import org.whispersystems.textsecuregcm.spam.ScoreThresholdProvider;
 import org.whispersystems.textsecuregcm.tests.util.AuthHelper;
 import org.whispersystems.textsecuregcm.util.SystemMapper;
 
@@ -44,10 +55,24 @@ class ChallengeControllerTest {
 
   private static final ChallengeController challengeController = new ChallengeController(rateLimitChallengeManager);
 
+  private static final AtomicReference<Float> scoreThreshold = new AtomicReference<>();
+
   private static final ResourceExtension EXTENSION = ResourceExtension.builder()
       .addProvider(AuthHelper.getAuthFilter())
       .addProvider(new PolymorphicAuthValueFactoryProvider.Binder<>(
           Set.of(AuthenticatedAccount.class, DisabledPermittedAuthenticatedAccount.class)))
+      .addProvider(ScoreThresholdProvider.ScoreThresholdFeature.class)
+      .addProvider(PushChallengeConfigProvider.PushChallengeConfigFeature.class)
+      .addProvider(new Feature() {
+          public boolean configure(FeatureContext featureContext) {
+            featureContext.register(new ContainerRequestFilter() {
+                public void filter(ContainerRequestContext requestContext) {
+                  requestContext.setProperty(ScoreThreshold.PROPERTY_NAME, scoreThreshold.get());
+                }
+              });
+            return true;
+          }
+        })
       .setMapper(SystemMapper.jsonMapper())
       .setTestContainerFactory(new GrizzlyWebTestContainerFactory())
       .addResource(new RateLimitExceededExceptionMapper())
@@ -57,6 +82,7 @@ class ChallengeControllerTest {
   @AfterEach
   void teardown() {
     reset(rateLimitChallengeManager);
+    scoreThreshold.set(null);
   }
 
   @Test
@@ -99,8 +125,9 @@ class ChallengeControllerTest {
     assertEquals(String.valueOf(retryAfter.toSeconds()), response.getHeaderString("Retry-After"));
   }
 
-  @Test
+  @ParameterizedTest
-  void testHandleRecaptcha() throws RateLimitExceededException, IOException {
+  @ValueSource(booleans = { true, false } )
+  void testHandleRecaptcha(boolean hasThreshold) throws RateLimitExceededException, IOException {
     final String recaptchaChallengeJson = """
         {
           "type": "recaptcha",
@@ -109,9 +136,13 @@ class ChallengeControllerTest {
         }
         """;
 
-    when(rateLimitChallengeManager.answerRecaptchaChallenge(any(), any(), any(), any()))
+    when(rateLimitChallengeManager.answerRecaptchaChallenge(any(), any(), any(), any(), any()))
         .thenReturn(true);
 
+
+    if (hasThreshold) {
+      scoreThreshold.set(Float.valueOf(0.5f));
+    }
     final Response response = EXTENSION.target("/v1/challenge")
         .request()
         .header(HttpHeaders.X_FORWARDED_FOR, "10.0.0.1")
@@ -120,7 +151,7 @@ class ChallengeControllerTest {
 
     assertEquals(200, response.getStatus());
 
-    verify(rateLimitChallengeManager).answerRecaptchaChallenge(eq(AuthHelper.VALID_ACCOUNT), eq("The value of the solved captcha token"), eq("10.0.0.1"), anyString());
+    verify(rateLimitChallengeManager).answerRecaptchaChallenge(eq(AuthHelper.VALID_ACCOUNT), eq("The value of the solved captcha token"), eq("10.0.0.1"), anyString(), eq(hasThreshold ? Optional.of(0.5f) : Optional.empty()));
   }
 
   @Test
@@ -132,8 +163,7 @@ class ChallengeControllerTest {
           "captcha": "The value of the solved captcha token"
         }
         """;
-
+   when(rateLimitChallengeManager.answerRecaptchaChallenge(eq(AuthHelper.VALID_ACCOUNT), eq("The value of the solved captcha token"), eq("10.0.0.1"), anyString(), any()))
-    when(rateLimitChallengeManager.answerRecaptchaChallenge(eq(AuthHelper.VALID_ACCOUNT), eq("The value of the solved captcha token"), eq("10.0.0.1"), anyString()))
         .thenReturn(false);
 
     final Response response = EXTENSION.target("/v1/challenge")
@@ -157,7 +187,7 @@ class ChallengeControllerTest {
 
     final Duration retryAfter = Duration.ofMinutes(17);
     doThrow(new RateLimitExceededException(retryAfter, true)).when(rateLimitChallengeManager)
-        .answerRecaptchaChallenge(any(), any(), any(), any());
+        .answerRecaptchaChallenge(any(), any(), any(), any(), any());
 
     final Response response = EXTENSION.target("/v1/challenge")
         .request()

service/src/test/java/org/whispersystems/textsecuregcm/limits/RateLimitChallengeManagerTest.java

@@ -13,9 +13,14 @@ import static org.mockito.Mockito.verifyNoInteractions;
 import static org.mockito.Mockito.when;
 
 import java.io.IOException;
+import java.util.Optional;
 import java.util.UUID;
+import java.util.stream.Stream;
+
 import org.junit.jupiter.api.BeforeEach;
 import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
 import org.junit.jupiter.params.provider.ValueSource;
 import org.whispersystems.textsecuregcm.captcha.Action;
 import org.whispersystems.textsecuregcm.captcha.AssessmentResult;
@@ -27,6 +32,8 @@ import org.whispersystems.textsecuregcm.storage.Account;
 
 class RateLimitChallengeManagerTest {
 
+  private static final float DEFAULT_SCORE_THRESHOLD = 0.1f;
+
   private PushChallengeManager pushChallengeManager;
   private CaptchaChecker captchaChecker;
   private RateLimiters rateLimiters;
@@ -71,27 +78,39 @@ class RateLimitChallengeManagerTest {
   }
 
   @ParameterizedTest
-  @ValueSource(booleans = {true, false})
+  @MethodSource
-  void answerRecaptchaChallenge(final boolean successfulChallenge) throws RateLimitExceededException, IOException {
+  void answerRecaptchaChallenge(Optional<Float> scoreThreshold, float actualScore, boolean expectSuccess)
+    throws RateLimitExceededException, IOException {
     final Account account = mock(Account.class);
     when(account.getNumber()).thenReturn("+18005551234");
     when(account.getUuid()).thenReturn(UUID.randomUUID());
 
     when(captchaChecker.verify(eq(Action.CHALLENGE), any(), any()))
-        .thenReturn(successfulChallenge
+        .thenReturn(AssessmentResult.fromScore(actualScore, DEFAULT_SCORE_THRESHOLD));
-            ? AssessmentResult.alwaysValid()
-            : AssessmentResult.invalid());
 
     when(rateLimiters.getRecaptchaChallengeAttemptLimiter()).thenReturn(mock(RateLimiter.class));
     when(rateLimiters.getRecaptchaChallengeSuccessLimiter()).thenReturn(mock(RateLimiter.class));
     when(rateLimiters.getRateLimitResetLimiter()).thenReturn(mock(RateLimiter.class));
 
-    rateLimitChallengeManager.answerRecaptchaChallenge(account, "captcha", "10.0.0.1", "Test User-Agent");
+    rateLimitChallengeManager.answerRecaptchaChallenge(account, "captcha", "10.0.0.1", "Test User-Agent", scoreThreshold);
 
-    if (successfulChallenge) {
+    if (expectSuccess) {
       verify(rateLimitChallengeListener).handleRateLimitChallengeAnswered(account, ChallengeType.CAPTCHA);
     } else {
       verifyNoInteractions(rateLimitChallengeListener);
     }
   }
+
+  private static Stream<Arguments> answerRecaptchaChallenge() {
+    return Stream.of(
+        Arguments.of(Optional.empty(), 0.5f, true),
+        Arguments.of(Optional.empty(), 0.1f, true),
+        Arguments.of(Optional.empty(), 0.0f, false),
+        Arguments.of(Optional.of(0.1f), 0.5f, true),
+        Arguments.of(Optional.of(0.1f), 0.1f, true),
+        Arguments.of(Optional.of(0.1f), 0.0f, false),
+        Arguments.of(Optional.of(0.3f), 0.5f, true),
+        Arguments.of(Optional.of(0.3f), 0.1f, false),
+        Arguments.of(Optional.of(0.3f), 0.0f, false));
+  }
 }