fix(auth): wiring Auth/Sessions, нормализация email, GetUserByID для /me, 409 на дубль, timing-guard логина

internal/api/api.go

@@ -61,6 +61,7 @@ type ProviderRegistry interface {
 type AuthStore interface {
 	RegisterUser(ctx context.Context, email, passwordHash string) (store.User, store.Project, error)
 	GetUserByEmail(ctx context.Context, email string) (store.User, error)
+	GetUserByID(ctx context.Context, userID uuid.UUID) (store.User, error)
 	GetUserProject(ctx context.Context, userID uuid.UUID) (store.Project, error)
 }
 

internal/api/auth_handlers.go

@@ -2,17 +2,43 @@ package api
 
 import (
 	"context"
+	"errors"
 	"log"
 	"net/http"
+	"strings"
 	"time"
 
 	"github.com/google/uuid"
 
 	"github.com/vasyakrg/dns-autoresolver/internal/auth"
+	"github.com/vasyakrg/dns-autoresolver/internal/store"
 )
 
 const sessionCookieName = "session"
 
+// dummyPasswordHash is a valid-format argon2 hash with no real matching
+// password. handleLogin runs VerifyPassword against it whenever the email
+// lookup fails, so a login attempt for an unregistered email takes the same
+// wall-clock time as one for a registered email with a wrong password —
+// otherwise the timing difference would let an attacker enumerate which
+// emails are registered.
+var dummyPasswordHash string
+
+func init() {
+	h, err := auth.HashPassword("dns-autoresolver-timing-guard-dummy")
+	if err != nil {
+		panic("api: failed to initialize dummy password hash: " + err.Error())
+	}
+	dummyPasswordHash = h
+}
+
+// normalizeEmail trims surrounding whitespace and lowercases the email so
+// storage and lookup are always consistent regardless of how the client
+// cased or padded the input.
+func normalizeEmail(email string) string {
+	return strings.ToLower(strings.TrimSpace(email))
+}
+
 // ctxKeyUserID is a private context key carrying the authenticated user's ID.
 // Task 4's RequireAuth middleware sets it after validating the session
 // cookie; handleMe reads it back.
@@ -45,7 +71,8 @@ func (a *API) handleRegister(w http.ResponseWriter, r *http.Request) {
 	if !decodeBody(w, r, &req) {
 		return
 	}
-	if req.Email == "" || req.Password == "" {
+	email := normalizeEmail(req.Email)
+	if email == "" || req.Password == "" {
 		writeErr(w, http.StatusBadRequest, "email and password are required")
 		return
 	}
@@ -57,8 +84,12 @@ func (a *API) handleRegister(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	u, p, err := a.Auth.RegisterUser(r.Context(), req.Email, hash)
+	u, p, err := a.Auth.RegisterUser(r.Context(), email, hash)
 	if err != nil {
+		if errors.Is(err, store.ErrEmailTaken) {
+			writeErr(w, http.StatusConflict, "email already registered")
+			return
+		}
 		log.Printf("api: register user failed: %v", err)
 		writeErr(w, http.StatusInternalServerError, "internal error")
 		return
@@ -87,9 +118,14 @@ func (a *API) handleLogin(w http.ResponseWriter, r *http.Request) {
 	if !decodeBody(w, r, &req) {
 		return
 	}
+	email := normalizeEmail(req.Email)
 
-	u, err := a.Auth.GetUserByEmail(r.Context(), req.Email)
+	u, err := a.Auth.GetUserByEmail(r.Context(), email)
 	if err != nil {
+		// No such user: still spend the argon2 verification cost against a
+		// fixed dummy hash (see dummyPasswordHash) so this path isn't
+		// distinguishable by timing from a wrong-password rejection below.
+		_, _ = auth.VerifyPassword(dummyPasswordHash, req.Password)
 		invalidCredentials(w)
 		return
 	}
@@ -131,8 +167,7 @@ func (a *API) handleLogout(w http.ResponseWriter, r *http.Request) {
 // handleMe returns the authenticated caller's identity + default project.
 // The user ID comes from the request context, set by Task 4's RequireAuth
 // middleware after validating the session cookie (tests set it directly via
-// context.WithValue in the interim). AuthStore has no GetUserByID — the
-// email field is intentionally left empty here; see task-3-report.md.
+// context.WithValue in the interim).
 func (a *API) handleMe(w http.ResponseWriter, r *http.Request) {
 	userID, ok := userIDFromContext(r.Context())
 	if !ok {
@@ -140,6 +175,13 @@ func (a *API) handleMe(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	u, err := a.Auth.GetUserByID(r.Context(), userID)
+	if err != nil {
+		log.Printf("api: get user by id failed: %v", err)
+		writeErr(w, http.StatusInternalServerError, "internal error")
+		return
+	}
+
 	p, err := a.Auth.GetUserProject(r.Context(), userID)
 	if err != nil {
 		log.Printf("api: get user project failed: %v", err)
@@ -147,8 +189,5 @@ func (a *API) handleMe(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	writeJSON(w, http.StatusOK, authResponse{
-		User:    userResponse{ID: userID.String()},
-		Project: projectResponse{ID: p.ID.String(), Name: p.Name},
-	})
+	writeJSON(w, http.StatusOK, toAuthResponse(u, p))
 }

internal/api/auth_test.go

@@ -20,6 +20,7 @@ import (
 type mockAuthStore struct {
 	registerUserFn   func(ctx context.Context, email, passwordHash string) (store.User, store.Project, error)
 	getUserByEmailFn func(ctx context.Context, email string) (store.User, error)
+	getUserByIDFn    func(ctx context.Context, userID uuid.UUID) (store.User, error)
 	getUserProjectFn func(ctx context.Context, userID uuid.UUID) (store.Project, error)
 }
 
@@ -31,6 +32,10 @@ func (m *mockAuthStore) GetUserByEmail(ctx context.Context, email string) (store
 	return m.getUserByEmailFn(ctx, email)
 }
 
+func (m *mockAuthStore) GetUserByID(ctx context.Context, userID uuid.UUID) (store.User, error) {
+	return m.getUserByIDFn(ctx, userID)
+}
+
 func (m *mockAuthStore) GetUserProject(ctx context.Context, userID uuid.UUID) (store.Project, error) {
 	return m.getUserProjectFn(ctx, userID)
 }
@@ -125,6 +130,59 @@ func TestAuthRegister_Success(t *testing.T) {
 	}
 }
 
+// TestAuthRegister_NormalizesEmail verifies the fix for the email-consistency
+// gap: a padded/mixed-case email is trimmed+lowercased before it reaches the
+// store, so storage and later lookups are always consistent.
+func TestAuthRegister_NormalizesEmail(t *testing.T) {
+	a, authStore, _ := newTestAuthAPI()
+	userID := uuid.New()
+	var gotEmail string
+	authStore.registerUserFn = func(_ context.Context, email, passwordHash string) (store.User, store.Project, error) {
+		gotEmail = email
+		return store.User{ID: userID, Email: email}, store.Project{ID: uuid.New(), UserID: userID, Name: "default"}, nil
+	}
+
+	router := NewRouter(a)
+	body := `{"email":"  Alice@X.com  ","password":"correct-horse"}`
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/register", strings.NewReader(body))
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status %d, body %s", w.Code, w.Body.String())
+	}
+	if gotEmail != "alice@x.com" {
+		t.Fatalf("expected normalized email passed to RegisterUser, got %q", gotEmail)
+	}
+}
+
+// TestAuthRegister_DuplicateEmailReturns409 verifies the fix for the
+// duplicate-registration gap: RegisterUser reporting store.ErrEmailTaken
+// must surface as 409, not a generic 500.
+func TestAuthRegister_DuplicateEmailReturns409(t *testing.T) {
+	a, authStore, _ := newTestAuthAPI()
+	authStore.registerUserFn = func(context.Context, string, string) (store.User, store.Project, error) {
+		return store.User{}, store.Project{}, store.ErrEmailTaken
+	}
+
+	router := NewRouter(a)
+	body := `{"email":"dup@example.com","password":"correct-horse"}`
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/register", strings.NewReader(body))
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+
+	if w.Code != http.StatusConflict {
+		t.Fatalf("status %d, body %s", w.Code, w.Body.String())
+	}
+	var got map[string]string
+	if err := json.Unmarshal(w.Body.Bytes(), &got); err != nil {
+		t.Fatal(err)
+	}
+	if got["error"] != "email already registered" {
+		t.Fatalf(`expected error "email already registered", got %q`, got["error"])
+	}
+}
+
 // --- login ---
 
 func TestAuthLogin_CorrectPassword(t *testing.T) {
@@ -159,6 +217,40 @@ func TestAuthLogin_CorrectPassword(t *testing.T) {
 	}
 }
 
+// TestAuthLogin_NormalizesEmail verifies that a login for a padded/mixed-case
+// email reaches GetUserByEmail already trimmed+lowercased — the same
+// normalization applied on register, so "Alice@X.com" at registration and
+// "alice@x.com" at login resolve to the same account.
+func TestAuthLogin_NormalizesEmail(t *testing.T) {
+	a, authStore, _ := newTestAuthAPI()
+	hash, err := auth.HashPassword("correct-horse")
+	if err != nil {
+		t.Fatal(err)
+	}
+	userID := uuid.New()
+	var gotEmail string
+	authStore.getUserByEmailFn = func(_ context.Context, email string) (store.User, error) {
+		gotEmail = email
+		return store.User{ID: userID, Email: email, PasswordHash: hash}, nil
+	}
+	authStore.getUserProjectFn = func(_ context.Context, uid uuid.UUID) (store.Project, error) {
+		return store.Project{ID: uuid.New(), UserID: uid, Name: "default"}, nil
+	}
+
+	router := NewRouter(a)
+	body := `{"email":"  Alice@X.com  ","password":"correct-horse"}`
+	req := httptest.NewRequest(http.MethodPost, "/api/v1/auth/login", strings.NewReader(body))
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status %d, body %s", w.Code, w.Body.String())
+	}
+	if gotEmail != "alice@x.com" {
+		t.Fatalf("expected normalized email passed to GetUserByEmail, got %q", gotEmail)
+	}
+}
+
 func TestAuthLogin_WrongPassword(t *testing.T) {
 	a, authStore, _ := newTestAuthAPI()
 	hash, err := auth.HashPassword("correct-horse")
@@ -240,6 +332,46 @@ func TestAuthLogout_ClearsSessionAndDestroys(t *testing.T) {
 	}
 }
 
+// --- me ---
+
+// TestAuthMe_ReturnsRealEmail verifies the fix for the /me gap: the handler
+// now resolves the authenticated user via GetUserByID and returns their real
+// email, instead of leaving it blank.
+func TestAuthMe_ReturnsRealEmail(t *testing.T) {
+	a, authStore, _ := newTestAuthAPI()
+	userID := uuid.New()
+	projectID := uuid.New()
+	authStore.getUserByIDFn = func(_ context.Context, id uuid.UUID) (store.User, error) {
+		if id != userID {
+			t.Fatalf("unexpected user id: %s", id)
+		}
+		return store.User{ID: userID, Email: "me@example.com"}, nil
+	}
+	authStore.getUserProjectFn = func(_ context.Context, uid uuid.UUID) (store.Project, error) {
+		return store.Project{ID: projectID, UserID: uid, Name: "default"}, nil
+	}
+
+	router := NewRouter(a)
+	req := httptest.NewRequest(http.MethodGet, "/api/v1/auth/me", nil)
+	req = req.WithContext(context.WithValue(req.Context(), ctxKeyUserID{}, userID))
+	w := httptest.NewRecorder()
+	router.ServeHTTP(w, req)
+
+	if w.Code != http.StatusOK {
+		t.Fatalf("status %d, body %s", w.Code, w.Body.String())
+	}
+	var got authResponse
+	if err := json.Unmarshal(w.Body.Bytes(), &got); err != nil {
+		t.Fatal(err)
+	}
+	if got.User.ID != userID.String() || got.User.Email != "me@example.com" {
+		t.Fatalf("unexpected user in /me response: %+v", got.User)
+	}
+	if got.Project.ID != projectID.String() {
+		t.Fatalf("unexpected project in /me response: %+v", got.Project)
+	}
+}
+
 // errNoRowsForTest stands in for a "not found" error a real store would
 // return (e.g. pgx.ErrNoRows) — handlers must not distinguish it from any
 // other GetUserByEmail failure in the response they send.

internal/store/auth_test.go

@@ -1,6 +1,7 @@
 package store
 
 import (
+	"errors"
 	"testing"
 	"time"
 
@@ -57,6 +58,41 @@ func TestGetUserByEmail_FindsRegisteredUser(t *testing.T) {
 	}
 }
 
+// TestRegisterUser_DuplicateEmailReturnsErrEmailTaken verifies the fix for
+// the duplicate-registration gap: a second RegisterUser call for an
+// already-taken email must fail with the ErrEmailTaken sentinel (mapped from
+// the UNIQUE constraint violation on users.email), not a generic pgx error.
+func TestRegisterUser_DuplicateEmailReturnsErrEmailTaken(t *testing.T) {
+	s, ctx := newStore(t)
+
+	if _, _, err := s.RegisterUser(ctx, "dup@example.com", "argon2-hash"); err != nil {
+		t.Fatal(err)
+	}
+
+	if _, _, err := s.RegisterUser(ctx, "dup@example.com", "argon2-hash"); !errors.Is(err, ErrEmailTaken) {
+		t.Fatalf("expected ErrEmailTaken, got %v", err)
+	}
+}
+
+// TestGetUserByID_ReturnsUser verifies the fix for the /me gap: GetUserByID
+// returns the same user created by RegisterUser, including their real email.
+func TestGetUserByID_ReturnsUser(t *testing.T) {
+	s, ctx := newStore(t)
+
+	u, _, err := s.RegisterUser(ctx, "gina@example.com", "argon2-hash")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	got, err := s.GetUserByID(ctx, u.ID)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if got.ID != u.ID || got.Email != "gina@example.com" {
+		t.Fatalf("unexpected user: %+v", got)
+	}
+}
+
 // TestSessionLifecycle_CreateGetDelete verifies CreateSession + GetSessionUser
 // round-trips to the owning user ID, an expired session is excluded from
 // GetSessionUser, and DeleteSession removes the session.

internal/store/db/users.sql.go

@@ -48,3 +48,19 @@ func (q *Queries) GetUserByEmail(ctx context.Context, email string) (User, error
 	)
 	return i, err
 }
+
+const getUserByID = `-- name: GetUserByID :one
+SELECT id, email, created_at, password_hash FROM users WHERE id = $1
+`
+
+func (q *Queries) GetUserByID(ctx context.Context, id uuid.UUID) (User, error) {
+	row := q.db.QueryRow(ctx, getUserByID, id)
+	var i User
+	err := row.Scan(
+		&i.ID,
+		&i.Email,
+		&i.CreatedAt,
+		&i.PasswordHash,
+	)
+	return i, err
+}

internal/store/queries/users.sql

@@ -3,3 +3,6 @@ INSERT INTO users (id, email, password_hash) VALUES ($1, $2, $3) RETURNING *;
 
 -- name: GetUserByEmail :one
 SELECT * FROM users WHERE email = $1;
+
+-- name: GetUserByID :one
+SELECT * FROM users WHERE id = $1;

internal/store/tenant.go

@@ -7,6 +7,7 @@ import (
 
 	"github.com/google/uuid"
 	"github.com/jackc/pgx/v5"
+	"github.com/jackc/pgx/v5/pgconn"
 	"github.com/jackc/pgx/v5/pgtype"
 
 	"github.com/vasyakrg/dns-autoresolver/internal/provider"
@@ -14,6 +15,11 @@ import (
 	"github.com/vasyakrg/dns-autoresolver/internal/store/dto"
 )
 
+// ErrEmailTaken is returned by RegisterUser when the email is already
+// registered — a UNIQUE constraint violation (pgerrcode 23505) on
+// users.email.
+var ErrEmailTaken = errors.New("store: email already registered")
+
 // Account/Template/Domain are provider-neutral domain structs returned by the
 // thin wrappers below, so callers (internal/api) never need to import
 // internal/store/db directly.
@@ -279,6 +285,17 @@ func (s *Store) GetUserByEmail(ctx context.Context, email string) (User, error)
 	return toUser(u), nil
 }
 
+// GetUserByID looks up a user by primary key — used by handleMe (Task 3
+// hardening) to return the authenticated caller's real email instead of
+// leaving it blank.
+func (s *Store) GetUserByID(ctx context.Context, id uuid.UUID) (User, error) {
+	u, err := s.q.GetUserByID(ctx, id)
+	if err != nil {
+		return User{}, err
+	}
+	return toUser(u), nil
+}
+
 func (s *Store) CreateProjectForUser(ctx context.Context, userID uuid.UUID, name string) (Project, error) {
 	p, err := s.q.CreateProject(ctx, db.CreateProjectParams{ID: uuid.New(), UserID: userID, Name: name})
 	if err != nil {
@@ -337,6 +354,10 @@ func (s *Store) RegisterUser(ctx context.Context, email, passwordHash string) (U
 	uid := uuid.New()
 	dbu, err := q.CreateUser(ctx, db.CreateUserParams{ID: uid, Email: email, PasswordHash: ptr(passwordHash)})
 	if err != nil {
+		var pgErr *pgconn.PgError
+		if errors.As(err, &pgErr) && pgErr.Code == "23505" {
+			return User{}, Project{}, ErrEmailTaken
+		}
 		return User{}, Project{}, err
 	}
 	dbp, err := q.CreateProject(ctx, db.CreateProjectParams{ID: uuid.New(), UserID: uid, Name: "default"})