fix(registration): check input and store emails in lower case

readme.md

@@ -13,7 +13,8 @@ To Be Played is split into three repositories:
 
 ## Features
 
-- Registration with an invitation code, login with email and password (BCrypt).
+- Registration with an invitation code, login with email and password (BCrypt). Emails are stored trimmed and in
+  lower case (V19, unique on `lower(email)`); a password has 8 characters and at most 72 bytes (BCrypt's limit).
 - Brute-force protection in memory: 5 failed logins per email or 20 per IP, and 10 failed registrations per IP,
   block for 15 minutes with `429 TOO_MANY_ATTEMPTS` and `Retry-After`. Unknown emails cost the same BCrypt time as a
   wrong password, and every failed login gets the same error.

src/main/java/auth_service/modules/login/api/dto/request/LoginRequest.java

@@ -1,5 +1,6 @@
 package auth_service.modules.login.api.dto.request;
 
+import auth_service.shared.account.EmailAddress;
 import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.NotNull;
 
@@ -7,4 +8,8 @@ import jakarta.validation.constraints.NotNull;
  * DTO (Data Transfer Object) representing the incoming login request.
  */
 public record LoginRequest(@NotNull String email, @NotNull @NotBlank String password) {
+
+    public LoginRequest {
+        email = EmailAddress.normalize(email);
+    }
 }

src/main/java/auth_service/modules/login/persistence/MinimalUserRepositoryImpl.java

@@ -1,5 +1,6 @@
 package auth_service.modules.login.persistence;
 
+import auth_service.shared.account.EmailAddress;
 import auth_service.modules.login.model.User;
 import auth_service.modules.login.persistence.entities.MinimalUserEntity;
 import auth_service.modules.login.persistence.mapper.EntityMapper;
@@ -25,8 +26,8 @@ public class MinimalUserRepositoryImpl implements MinimalUserRepository {
         var userEntityCriteriaQuery = criteriaBuilder.createQuery(MinimalUserEntity.class);
         var userEntity = userEntityCriteriaQuery.from(MinimalUserEntity.class);
 
-        // Build the query: SELECT u FROM UserEntity u WHERE u.email = :email
-        userEntityCriteriaQuery.select(userEntity).where(criteriaBuilder.equal(userEntity.get("email"), email));
+        userEntityCriteriaQuery.select(userEntity).where(criteriaBuilder.equal(
+                userEntity.get("email"), EmailAddress.normalize(email)));
 
         TypedQuery<MinimalUserEntity> typedQuery = entityManager.createQuery(userEntityCriteriaQuery);
 

src/main/java/auth_service/modules/login/service/LoginAttemptService.java

@@ -1,11 +1,11 @@
 package auth_service.modules.login.service;
 
 import auth_service.modules.login.exception.TooManyLoginAttemptsException;
+import auth_service.shared.account.EmailAddress;
 import auth_service.shared.security.AttemptLimiter;
 import org.springframework.stereotype.Service;
 
 import java.time.Duration;
-import java.util.Locale;
 
 /**
  * Counts failed logins per email and per client IP in memory. A key is blocked after too many
@@ -37,7 +37,7 @@ public class LoginAttemptService {
     }
 
     private static String emailKey(String email) {
-        return "email:" + (email == null ? "" : email.trim().toLowerCase(Locale.ROOT));
+        return "email:" + (email == null ? "" : EmailAddress.normalize(email));
     }
 
     private static String ipKey(String clientIp) {

src/main/java/auth_service/modules/registration/api/dto/request/RegistrationRequest.java

@@ -1,13 +1,36 @@
 package auth_service.modules.registration.api.dto.request;
 
 import auth_service.shared.api.validation.DisplayNameFormat;
+import auth_service.shared.account.EmailAddress;
+import com.fasterxml.jackson.annotation.JsonIgnore;
+import jakarta.validation.constraints.AssertTrue;
+import jakarta.validation.constraints.Email;
+import jakarta.validation.constraints.NotBlank;
 import jakarta.validation.constraints.Pattern;
+import jakarta.validation.constraints.Size;
 import lombok.Builder;
 
+import java.nio.charset.StandardCharsets;
+
 /**
  * No Steam ID: it comes only from "Sign in through Steam", later in the settings.
  */
 @Builder
-public record RegistrationRequest(String email, String password, String inviteCode,
+public record RegistrationRequest(@NotBlank @Email @Size(max = EmailAddress.MAX_LENGTH) String email,
+                                  @NotBlank @Size(min = 8) String password,
+                                  @NotBlank String inviteCode,
                                   @Pattern(regexp = DisplayNameFormat.PATTERN) String displayName) {
+
+    public RegistrationRequest {
+        email = EmailAddress.normalize(email);
+    }
+
+    /**
+     * BCrypt uses only the first 72 bytes and refuses a longer password.
+     */
+    @AssertTrue(message = "The password may have at most 72 bytes")
+    @JsonIgnore
+    public boolean isPasswordShortEnough() {
+        return password == null || password.getBytes(StandardCharsets.UTF_8).length <= 72;
+    }
 }

src/main/java/auth_service/modules/registration/persistence/RegisteredUserRepositoryImpl.java

@@ -1,5 +1,6 @@
 package auth_service.modules.registration.persistence;
 
+import auth_service.shared.account.EmailAddress;
 import auth_service.modules.registration.model.Registration;
 import auth_service.modules.registration.persistence.mapper.EntityMapper;
 import jakarta.persistence.EntityManager;
@@ -18,7 +19,7 @@ public class RegisteredUserRepositoryImpl implements RegisteredUserRepository {
     public boolean existsByEmail(String email) {
         var jpql = "SELECT COUNT(u) FROM UserEntity u WHERE u.email = :email";
         var count = entityManager.createQuery(jpql, Long.class)
-                .setParameter("email", email)
+                .setParameter("email", EmailAddress.normalize(email))
                 .getSingleResult();
 
         return count != null && count > 0;

src/main/java/auth_service/modules/user/persistence/UserRepositoryImpl.java

@@ -1,5 +1,6 @@
 package auth_service.modules.user.persistence;
 
+import auth_service.shared.account.EmailAddress;
 import auth_service.modules.user.exception.UserNotFoundException;
 import auth_service.modules.user.model.Appearance;
 import auth_service.modules.user.model.ProfileStyle;
@@ -36,8 +37,8 @@ public class UserRepositoryImpl implements UserRepository {
         // A LEFT JOIN ensures the user is returned even if no settings exist yet.
         userEntity.fetch("settings", jakarta.persistence.criteria.JoinType.LEFT);
 
-        // Build the query: SELECT u FROM UserEntity u LEFT JOIN FETCH u.settings WHERE u.email = :email
-        userEntityCriteriaQuery.select(userEntity).where(criteriaBuilder.equal(userEntity.get("email"), email));
+        userEntityCriteriaQuery.select(userEntity).where(criteriaBuilder.equal(
+                userEntity.get("email"), EmailAddress.normalize(email)));
 
         TypedQuery<UserEntity> typedQuery = entityManager.createQuery(userEntityCriteriaQuery);
 

src/main/java/auth_service/modules/user/persistence/mapper/EntityMapper.java

@@ -40,9 +40,9 @@ public abstract class EntityMapper {
                     .favoritePlatform(entity.getSettings().getFavoritePlatform())
                     .build();
         } else {
-            // Fallback default settings for users without an entry in the database
+            // No settings row. "" means no language chosen, as in a new row; the frontend keeps its own.
             settingsModel = UserSettings.builder()
-                    .language("en")
+                    .language("")
                     .theme("system")
                     .build();
         }

src/main/java/auth_service/shared/account/EmailAddress.java

@@ -0,0 +1,19 @@
+package auth_service.shared.account;
+
+import java.util.Locale;
+
+/**
+ * One account per address, whatever case the user types: emails are stored and looked up trimmed and in lower case
+ * (V19 has a unique index on lower(email)). Look-ups normalize too: an access token from before V19 still carries
+ * the email as it was typed.
+ */
+public final class EmailAddress {
+    public static final int MAX_LENGTH = 254;
+
+    private EmailAddress() {
+    }
+
+    public static String normalize(String email) {
+        return email == null ? null : email.strip().toLowerCase(Locale.ROOT);
+    }
+}

src/main/resources/db/migration/V19__Email_Lower_Case.sql

@@ -0,0 +1,4 @@
+-- One account per address, whatever case the user types (EmailAddress). Checked on prod before: no two emails
+-- differ only in case, so the update cannot collide.
+UPDATE users SET email = lower(trim(email)) WHERE email <> lower(trim(email));
+CREATE UNIQUE INDEX users_email_lower ON users (lower(email));

src/test/java/auth_service/modules/login/api/LoginControllerTest.java

@@ -13,6 +13,7 @@ import auth_service.shared.security.SessionProperties;
 import jakarta.servlet.http.Cookie;
 import auth_service.shared.test.AbstractWebMvcTest;
 import org.junit.jupiter.api.Test;
+import org.mockito.ArgumentCaptor;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.json.AutoConfigureJsonTesters;
 import org.springframework.boot.test.json.JacksonTester;
@@ -26,6 +27,7 @@ import org.springframework.test.web.servlet.MockMvc;
 
 import java.util.Optional;
 
+import static org.junit.jupiter.api.Assertions.assertEquals;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.verify;
@@ -183,4 +185,18 @@ class LoginControllerTest extends AbstractWebMvcTest {
 
         verify(refreshTokenService).revoke("the-refresh");
     }
+
+    @Test
+    void login_Email_IsTrimmedAndLowerCase() throws Exception {
+        when(loginService.login(any(User.class), any(), any())).thenReturn(new Session("mock-access", "mock-refresh"));
+
+        mockMvc.perform(post("/api/auth/login")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(loginRequestJson.write(new LoginRequest(" Bob@Example.COM ", "password")).getJson()))
+                .andExpect(status().isOk());
+
+        ArgumentCaptor<User> user = ArgumentCaptor.forClass(User.class);
+        verify(loginService).login(user.capture(), any(), any());
+        assertEquals("bob@example.com", user.getValue().getEmail());
+    }
 }

src/test/java/auth_service/modules/login/persistence/MinimalUserRepositoryTest.java

@@ -57,4 +57,13 @@ class MinimalUserRepositoryTest extends AbstractPersistenceTest {
         var updated = entityManager.find(MinimalUserEntity.class, entity.getId());
         assertNotNull(updated.getLastLoginDate());
     }
+
+    // An access token from before V19 still carries the email as it was typed.
+    @Test
+    void findByEmail_IgnoresCase() {
+        entityManager.persist(MinimalUserEntity.builder().email("case@example.com").password("password").enabled(true).build());
+        entityManager.flush();
+
+        assertTrue(minimalUserRepository.findByEmail("Case@Example.com").isPresent());
+    }
 }

src/test/java/auth_service/modules/registration/api/RegistrationControllerTest.java

@@ -9,6 +9,8 @@ import auth_service.modules.registration.model.Registration;
 import auth_service.modules.registration.service.RegistrationService;
 import auth_service.shared.test.AbstractWebMvcTest;
 import org.junit.jupiter.api.Test;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.CsvSource;
 import org.mockito.ArgumentCaptor;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.boot.test.autoconfigure.json.AutoConfigureJsonTesters;
@@ -187,4 +189,53 @@ class RegistrationControllerTest extends AbstractWebMvcTest {
                 .andExpect(header().string("Retry-After", "900"))
                 .andExpect(jsonPath("$.code").value("TOO_MANY_ATTEMPTS"));
     }
+
+    @ParameterizedTest
+    @CsvSource(delimiter = '|', value = {
+            " |SuperSecret123!|code",
+            "no-at-sign|SuperSecret123!|code",
+            "test@example.com| |code",
+            "test@example.com|short|code",
+            "test@example.com|SuperSecret123!| ",
+    })
+    void register_InvalidInput_Is400WithoutRegistering(String email, String password, String inviteCode) throws Exception {
+        var request = RegistrationRequest.builder().email(email).password(password).inviteCode(inviteCode).build();
+
+        mockMvc.perform(post("/api/registration/new")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(registrationRequestJson.write(request).getJson()))
+                .andExpect(status().isBadRequest());
+
+        verifyNoInteractions(registrationService);
+    }
+
+    // BCrypt uses only 72 bytes: a longer password would mostly be ignored, or refused with a 500.
+    @Test
+    void register_PasswordOver72Bytes_Is400() throws Exception {
+        var request = RegistrationRequest.builder().email("test@example.com").password("é".repeat(37))
+                .inviteCode("code").build();
+
+        mockMvc.perform(post("/api/registration/new")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(registrationRequestJson.write(request).getJson()))
+                .andExpect(status().isBadRequest());
+
+        verifyNoInteractions(registrationService);
+    }
+
+    @Test
+    void register_Email_IsTrimmedAndLowerCase() throws Exception {
+        var request = RegistrationRequest.builder().email(" Bob@Example.COM ").password("SuperSecret123!")
+                .inviteCode("code").build();
+        when(registrationService.register(any(Registration.class), any())).thenReturn(1L);
+
+        mockMvc.perform(post("/api/registration/new")
+                        .contentType(MediaType.APPLICATION_JSON)
+                        .content(registrationRequestJson.write(request).getJson()))
+                .andExpect(status().isOk());
+
+        ArgumentCaptor<Registration> registration = ArgumentCaptor.forClass(Registration.class);
+        verify(registrationService).register(registration.capture(), any());
+        assertEquals("bob@example.com", registration.getValue().getEmail());
+    }
 }

src/test/java/auth_service/modules/registration/persistence/RegisteredUserRepositoryTest.java

@@ -54,4 +54,19 @@ class RegisteredUserRepositoryTest extends AbstractPersistenceTest {
         assertNotNull(saved);
         assertEquals("save@example.com", saved.getEmail());
     }
+
+    // V19: a second account under the same email in other case is refused by the database too.
+    @Test
+    void emailsThatDifferOnlyInCase_AreOneAccount() {
+        entityManager.persist(RegisteredUserEntity.builder().email("dup@example.com").password("password")
+                .enabled(true).registrationDate(java.time.LocalDateTime.now()).build());
+        entityManager.flush();
+
+        assertTrue(registeredUserRepository.existsByEmail("Dup@Example.com"));
+        assertThrows(org.hibernate.exception.ConstraintViolationException.class, () -> {
+            entityManager.persist(RegisteredUserEntity.builder().email("Dup@example.com").password("password")
+                    .enabled(true).registrationDate(java.time.LocalDateTime.now()).build());
+            entityManager.flush();
+        });
+    }
 }

src/test/java/auth_service/modules/user/persistence/mapper/EntityMapperTest.java

@@ -0,0 +1,16 @@
+package auth_service.modules.user.persistence.mapper;
+
+import auth_service.modules.user.persistence.entities.UserEntity;
+import org.junit.jupiter.api.Test;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+class EntityMapperTest {
+
+    @Test
+    void mapToModel_UserWithoutSettingsRow_HasNoLanguage() {
+        UserEntity entity = UserEntity.builder().id(1L).email("a@b.c").role("USER").build();
+
+        assertThat(EntityMapper.mapToModel(entity).getSettings().getLanguage()).isEmpty();
+    }
+}