feat(admin): add administrator sessions

admin/README.md

@@ -0,0 +1,22 @@
+# 采购服务
+
+启动前必须显式设置下列环境变量；服务不提供默认管理员账号、密码或会话密钥。
+
+| 变量 | 要求 |
+| --- | --- |
+| `CMBUYER_ADMIN_USERNAME` | 非空管理员账号。 |
+| `CMBUYER_ADMIN_PASSWORD_BCRYPT` | 非空 bcrypt 密码哈希，不接受明文密码。 |
+| `CMBUYER_SESSION_SECRET` | 至少 32 字节的会话签名密钥。 |
+| `CMBUYER_COOKIE_SECURE` | 可选；存在时只能精确为 `true` 或 `false`。HTTPS 部署应设为 `true`。 |
+
+示例仅展示变量名，不提供可运行凭据：
+
+```powershell
+$env:CMBUYER_ADMIN_USERNAME = '<管理员账号>'
+$env:CMBUYER_ADMIN_PASSWORD_BCRYPT = '<bcrypt 密码哈希>'
+$env:CMBUYER_SESSION_SECRET = '<至少 32 字节的随机密钥>'
+$env:CMBUYER_COOKIE_SECURE = 'true'
+go run ./cmd/server
+```
+
+采购服务会话仅保存在当前进程内；进程重启后既有登录会话会安全失效。

admin/cmd/server/main.go

@@ -5,6 +5,8 @@ import (
 	"log"
 	"net/http"
 
+	"cmbuyer/admin/internal/auth"
+	"cmbuyer/admin/internal/config"
 	"cmbuyer/admin/internal/server"
 )
 
@@ -17,7 +19,21 @@ func main() {
 }
 
 func run() error {
-	err := http.ListenAndServe(listenAddress, server.NewRouter())
+	configuration, err := config.LoadFromEnv()
+	if err != nil {
+		return err
+	}
+
+	router, err := server.NewRouter(server.Options{
+		AdminUsername:       configuration.AdminUsername,
+		AdminPasswordBcrypt: configuration.AdminPasswordBcrypt,
+		Sessions:            auth.NewManager(configuration.SessionSecret, configuration.CookieSecure),
+	})
+	if err != nil {
+		return err
+	}
+
+	err = http.ListenAndServe(listenAddress, router)
 	if errors.Is(err, http.ErrServerClosed) {
 		return nil
 	}

admin/go.mod

@@ -6,6 +6,7 @@ require (
 	github.com/gin-gonic/gin v1.11.0
 	github.com/mattn/go-sqlite3 v1.14.49
 	github.com/pressly/goose/v3 v3.24.0
+	golang.org/x/crypto v0.40.0
 )
 
 require (
@@ -35,7 +36,6 @@ require (
 	go.uber.org/mock v0.5.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/arch v0.20.0 // indirect
-	golang.org/x/crypto v0.40.0 // indirect
 	golang.org/x/mod v0.25.0 // indirect
 	golang.org/x/net v0.42.0 // indirect
 	golang.org/x/sync v0.16.0 // indirect

admin/internal/auth/session.go

@@ -0,0 +1,198 @@
+// Package auth 提供内存会话与 CSRF 防护。会话不落库，服务重启会安全地使所有登录失效。
+package auth
+
+import (
+	"crypto/hmac"
+	"crypto/rand"
+	"crypto/sha256"
+	"crypto/subtle"
+	"encoding/base64"
+	"io"
+	"net/http"
+	"strconv"
+	"strings"
+	"sync"
+	"time"
+)
+
+const (
+	CookieName        = "cmbuyer_session"
+	SessionLifetime   = 8 * time.Hour
+	csrfTokenByteSize = 32
+)
+
+type session struct {
+	csrfToken     string
+	authenticated bool
+	expiresAt     time.Time
+}
+
+// Manager 签发、验证并撤销进程内会话。cookie 仅承载经过 HMAC 签名的随机 session ID。
+type Manager struct {
+	secret       []byte
+	cookieSecure bool
+	now          func() time.Time
+	random       io.Reader
+
+	mu       sync.Mutex
+	sessions map[string]session
+}
+
+// NewManager 创建会话管理器。secret 在启动时已由 config 验证为足够长度。
+func NewManager(secret []byte, cookieSecure bool) *Manager {
+	return &Manager{
+		secret:       append([]byte(nil), secret...),
+		cookieSecure: cookieSecure,
+		now:          time.Now,
+		random:       rand.Reader,
+		sessions:     make(map[string]session),
+	}
+}
+
+// Ensure 返回当前有效会话；不存在或过期时签发匿名会话，以保护登录表单本身的 POST。
+func (manager *Manager) Ensure(writer http.ResponseWriter, request *http.Request) (csrfToken string, authenticated bool) {
+	if id, current, ok := manager.current(request); ok {
+		return current.csrfToken, current.authenticated
+	} else if id != "" {
+		manager.delete(id)
+	}
+
+	id, current := manager.create(false)
+	manager.writeCookie(writer, id, current.expiresAt)
+	return current.csrfToken, false
+}
+
+// VerifyCSRF 只接受当前未过期会话中以恒定时间比较匹配的 token。
+func (manager *Manager) VerifyCSRF(request *http.Request, token string) (authenticated bool, ok bool) {
+	_, current, found := manager.current(request)
+	if !found || token == "" {
+		return false, false
+	}
+
+	if subtle.ConstantTimeCompare([]byte(current.csrfToken), []byte(token)) != 1 {
+		return false, false
+	}
+
+	return current.authenticated, true
+}
+
+// RotateAuthenticated 在登录成功后撤销旧会话并签发全新认证会话，避免 session fixation 与 CSRF 复用。
+func (manager *Manager) RotateAuthenticated(writer http.ResponseWriter, request *http.Request) string {
+	if id, _, ok := manager.current(request); ok {
+		manager.delete(id)
+	}
+
+	id, current := manager.create(true)
+	manager.writeCookie(writer, id, current.expiresAt)
+	return current.csrfToken
+}
+
+// Logout 撤销当前会话并立即清除浏览器 cookie。
+func (manager *Manager) Logout(writer http.ResponseWriter, request *http.Request) {
+	if id, _, ok := manager.current(request); ok {
+		manager.delete(id)
+	}
+	http.SetCookie(writer, &http.Cookie{
+		Name:     CookieName,
+		Value:    "",
+		Path:     "/",
+		MaxAge:   -1,
+		HttpOnly: true,
+		Secure:   manager.cookieSecure,
+		SameSite: http.SameSiteLaxMode,
+	})
+}
+
+func (manager *Manager) current(request *http.Request) (string, session, bool) {
+	cookie, err := request.Cookie(CookieName)
+	if err != nil {
+		return "", session{}, false
+	}
+
+	id, expiresAt, ok := manager.verifyCookie(cookie.Value)
+	if !ok || !manager.now().Before(expiresAt) {
+		return id, session{}, false
+	}
+
+	manager.mu.Lock()
+	defer manager.mu.Unlock()
+	current, found := manager.sessions[id]
+	if !found || !manager.now().Before(current.expiresAt) {
+		return id, session{}, false
+	}
+
+	return id, current, true
+}
+
+func (manager *Manager) create(authenticated bool) (string, session) {
+	id := manager.randomToken()
+	current := session{
+		csrfToken:     manager.randomToken(),
+		authenticated: authenticated,
+		expiresAt:     manager.now().Add(SessionLifetime),
+	}
+
+	manager.mu.Lock()
+	manager.sessions[id] = current
+	manager.mu.Unlock()
+	return id, current
+}
+
+func (manager *Manager) delete(id string) {
+	manager.mu.Lock()
+	delete(manager.sessions, id)
+	manager.mu.Unlock()
+}
+
+func (manager *Manager) randomToken() string {
+	bytes := make([]byte, csrfTokenByteSize)
+	if _, err := io.ReadFull(manager.random, bytes); err != nil {
+		panic("crypto/rand failed while creating a session token")
+	}
+	return base64.RawURLEncoding.EncodeToString(bytes)
+}
+
+func (manager *Manager) writeCookie(writer http.ResponseWriter, id string, expiresAt time.Time) {
+	http.SetCookie(writer, &http.Cookie{
+		Name:     CookieName,
+		Value:    manager.signCookie(id, expiresAt),
+		Path:     "/",
+		MaxAge:   int(expiresAt.Sub(manager.now()).Seconds()),
+		Expires:  expiresAt,
+		HttpOnly: true,
+		Secure:   manager.cookieSecure,
+		SameSite: http.SameSiteLaxMode,
+	})
+}
+
+func (manager *Manager) signCookie(id string, expiresAt time.Time) string {
+	payload := id + "." + strconv.FormatInt(expiresAt.Unix(), 10)
+	mac := hmac.New(sha256.New, manager.secret)
+	_, _ = mac.Write([]byte(payload))
+	return payload + "." + base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
+}
+
+func (manager *Manager) verifyCookie(value string) (string, time.Time, bool) {
+	parts := strings.Split(value, ".")
+	if len(parts) != 3 || parts[0] == "" {
+		return "", time.Time{}, false
+	}
+
+	expiresUnix, err := strconv.ParseInt(parts[1], 10, 64)
+	if err != nil {
+		return "", time.Time{}, false
+	}
+	provided, err := base64.RawURLEncoding.DecodeString(parts[2])
+	if err != nil {
+		return "", time.Time{}, false
+	}
+
+	payload := parts[0] + "." + parts[1]
+	mac := hmac.New(sha256.New, manager.secret)
+	_, _ = mac.Write([]byte(payload))
+	if !hmac.Equal(provided, mac.Sum(nil)) {
+		return "", time.Time{}, false
+	}
+
+	return parts[0], time.Unix(expiresUnix, 0), true
+}

admin/internal/auth/session_test.go

@@ -0,0 +1,49 @@
+package auth
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+	"time"
+)
+
+func TestManagerRejectsTamperedAndExpiredCookies(t *testing.T) {
+	manager := NewManager([]byte(strings.Repeat("s", 32)), true)
+	request := httptest.NewRequest(http.MethodGet, "/login", nil)
+	response := httptest.NewRecorder()
+	csrf, authenticated := manager.Ensure(response, request)
+	if csrf == "" || authenticated {
+		t.Fatalf("Ensure = (%q, %t), want anonymous CSRF session", csrf, authenticated)
+	}
+	cookie := response.Result().Cookies()[0]
+	if !cookie.HttpOnly || !cookie.Secure || cookie.SameSite != http.SameSiteLaxMode || cookie.Path != "/" {
+		t.Fatalf("session cookie is missing security attributes: %#v", cookie)
+	}
+
+	tampered := *cookie
+	tampered.Value = flipCookieValue(t, cookie.Value)
+	tamperedRequest := httptest.NewRequest(http.MethodPost, "/login", nil)
+	tamperedRequest.AddCookie(&tampered)
+	if _, ok := manager.VerifyCSRF(tamperedRequest, csrf); ok {
+		t.Fatal("tampered signed cookie passed CSRF verification")
+	}
+
+	manager.now = func() time.Time { return time.Now().Add(9 * time.Hour) }
+	expiredRequest := httptest.NewRequest(http.MethodPost, "/login", nil)
+	expiredRequest.AddCookie(cookie)
+	if _, ok := manager.VerifyCSRF(expiredRequest, csrf); ok {
+		t.Fatal("expired cookie passed CSRF verification")
+	}
+}
+
+func flipCookieValue(t *testing.T, value string) string {
+	t.Helper()
+	if value == "" {
+		t.Fatal("cannot tamper with an empty cookie")
+	}
+	if value[0] == 'A' {
+		return "B" + value[1:]
+	}
+	return "A" + value[1:]
+}

admin/internal/config/config.go

@@ -0,0 +1,84 @@
+// Package config 读取采购服务的启动配置。凭据只允许来自显式环境变量，避免把秘密写入代码或仓库。
+package config
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+const (
+	adminUsernameEnv       = "CMBUYER_ADMIN_USERNAME"
+	adminPasswordBcryptEnv = "CMBUYER_ADMIN_PASSWORD_BCRYPT"
+	sessionSecretEnv       = "CMBUYER_SESSION_SECRET"
+	cookieSecureEnv        = "CMBUYER_COOKIE_SECURE"
+	minimumSecretLength    = 32
+)
+
+// Config 是启动采购服务所需的最小安全配置。
+type Config struct {
+	AdminUsername       string
+	AdminPasswordBcrypt string
+	SessionSecret       []byte
+	CookieSecure        bool
+}
+
+// LoadFromEnv 从进程环境读取配置。错误只指出缺失或非法的变量名，绝不回显秘密。
+func LoadFromEnv() (Config, error) {
+	return Load(os.LookupEnv)
+}
+
+// Load 使用 lookup 读取配置，以便在不污染进程环境的情况下测试启动边界。
+func Load(lookup func(string) (string, bool)) (Config, error) {
+	username, err := required(lookup, adminUsernameEnv)
+	if err != nil {
+		return Config{}, err
+	}
+
+	passwordHash, err := required(lookup, adminPasswordBcryptEnv)
+	if err != nil {
+		return Config{}, err
+	}
+	if _, err := bcrypt.Cost([]byte(passwordHash)); err != nil {
+		return Config{}, fmt.Errorf("%s is not a valid bcrypt hash", adminPasswordBcryptEnv)
+	}
+
+	secret, err := required(lookup, sessionSecretEnv)
+	if err != nil {
+		return Config{}, err
+	}
+	if len([]byte(secret)) < minimumSecretLength {
+		return Config{}, fmt.Errorf("%s must be at least %d bytes", sessionSecretEnv, minimumSecretLength)
+	}
+
+	cookieSecure := false
+	if value, present := lookup(cookieSecureEnv); present {
+		switch value {
+		case "true":
+			cookieSecure = true
+		case "false":
+			cookieSecure = false
+		default:
+			return Config{}, fmt.Errorf("%s must be exactly true or false", cookieSecureEnv)
+		}
+	}
+
+	return Config{
+		AdminUsername:       username,
+		AdminPasswordBcrypt: passwordHash,
+		SessionSecret:       []byte(secret),
+		CookieSecure:        cookieSecure,
+	}, nil
+}
+
+func required(lookup func(string) (string, bool), name string) (string, error) {
+	value, present := lookup(name)
+	if !present || strings.TrimSpace(value) == "" {
+		return "", errors.New(name + " must be set")
+	}
+
+	return value, nil
+}

admin/internal/config/config_test.go

@@ -0,0 +1,82 @@
+package config_test
+
+import (
+	"strings"
+	"testing"
+
+	"cmbuyer/admin/internal/config"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+func TestLoad(t *testing.T) {
+	hash, err := bcrypt.GenerateFromPassword([]byte("test-password"), bcrypt.MinCost)
+	if err != nil {
+		t.Fatalf("generate bcrypt hash: %v", err)
+	}
+
+	values := map[string]string{
+		"CMBUYER_ADMIN_USERNAME":        "admin",
+		"CMBUYER_ADMIN_PASSWORD_BCRYPT": string(hash),
+		"CMBUYER_SESSION_SECRET":        strings.Repeat("s", 32),
+		"CMBUYER_COOKIE_SECURE":         "true",
+	}
+
+	got, err := config.Load(lookup(values))
+	if err != nil {
+		t.Fatalf("Load: %v", err)
+	}
+	if got.AdminUsername != "admin" || !got.CookieSecure {
+		t.Fatalf("Load returned unexpected public configuration: %#v", got)
+	}
+}
+
+func TestLoadRejectsMissingOrInvalidConfiguration(t *testing.T) {
+	hash, err := bcrypt.GenerateFromPassword([]byte("test-password"), bcrypt.MinCost)
+	if err != nil {
+		t.Fatalf("generate bcrypt hash: %v", err)
+	}
+
+	base := map[string]string{
+		"CMBUYER_ADMIN_USERNAME":        "admin",
+		"CMBUYER_ADMIN_PASSWORD_BCRYPT": string(hash),
+		"CMBUYER_SESSION_SECRET":        strings.Repeat("s", 32),
+	}
+
+	tests := []struct {
+		name   string
+		mutate func(map[string]string)
+		want   string
+	}{
+		{"missing username", func(values map[string]string) { delete(values, "CMBUYER_ADMIN_USERNAME") }, "CMBUYER_ADMIN_USERNAME"},
+		{"invalid bcrypt", func(values map[string]string) { values["CMBUYER_ADMIN_PASSWORD_BCRYPT"] = "not-a-bcrypt-hash" }, "CMBUYER_ADMIN_PASSWORD_BCRYPT"},
+		{"short secret", func(values map[string]string) { values["CMBUYER_SESSION_SECRET"] = "short" }, "CMBUYER_SESSION_SECRET"},
+		{"invalid secure flag", func(values map[string]string) { values["CMBUYER_COOKIE_SECURE"] = "1" }, "CMBUYER_COOKIE_SECURE"},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			values := copyValues(base)
+			test.mutate(values)
+			_, err := config.Load(lookup(values))
+			if err == nil || !strings.Contains(err.Error(), test.want) {
+				t.Fatalf("Load error = %v, want mention of %s", err, test.want)
+			}
+		})
+	}
+}
+
+func lookup(values map[string]string) func(string) (string, bool) {
+	return func(key string) (string, bool) {
+		value, ok := values[key]
+		return value, ok
+	}
+}
+
+func copyValues(values map[string]string) map[string]string {
+	copy := make(map[string]string, len(values))
+	for key, value := range values {
+		copy[key] = value
+	}
+	return copy
+}

admin/internal/server/router.go

@@ -2,18 +2,164 @@
 package server
 
 import (
+	"crypto/subtle"
+	"errors"
 	"net/http"
+	"net/url"
+	"strings"
+
+	"cmbuyer/admin/internal/auth"
+	"cmbuyer/admin/internal/transport/webui"
 
 	"github.com/gin-gonic/gin"
+	"golang.org/x/crypto/bcrypt"
 )
 
-// NewRouter 返回当前服务范围内的完整 HTTP 路由。
-func NewRouter() *gin.Engine {
-	router := gin.New()
+const maxFormBytes = 8 << 10
 
-	router.GET("/healthz", func(context *gin.Context) {
-		context.JSON(http.StatusOK, gin.H{"status": "ok"})
-	})
+// Options 是路由层需要的安全依赖。凭据由启动配置注入，不能在路由中设置默认值。
+type Options struct {
+	AdminUsername       string
+	AdminPasswordBcrypt string
+	Sessions            *auth.Manager
+}
 
-	return router
+// NewRouter 返回当前服务范围内的完整 HTTP 路由。
+func NewRouter(options Options) (*gin.Engine, error) {
+	if options.AdminUsername == "" || options.AdminPasswordBcrypt == "" || options.Sessions == nil {
+		return nil, errors.New("server authentication options are incomplete")
+	}
+
+	router := gin.New()
+	router.Use(gin.Recovery())
+	router.Use(securityHeaders())
+	router.GET("/healthz", healthz)
+	router.GET("/login", loginPage(options))
+	router.POST("/login", login(options))
+	router.POST("/logout", logout(options))
+	router.GET("/tasks", tasksPage(options))
+
+	return router, nil
+}
+
+func healthz(context *gin.Context) {
+	context.JSON(http.StatusOK, gin.H{"status": "ok"})
+}
+
+func securityHeaders() gin.HandlerFunc {
+	return func(context *gin.Context) {
+		context.Header("Cache-Control", "no-store")
+		context.Header("X-Content-Type-Options", "nosniff")
+		context.Header("Referrer-Policy", "no-referrer")
+		context.Header("Content-Security-Policy", "default-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'none'; object-src 'none'; base-uri 'none'; frame-ancestors 'none'; form-action 'self'")
+		context.Next()
+	}
+}
+
+func loginPage(options Options) gin.HandlerFunc {
+	return func(context *gin.Context) {
+		csrfToken, authenticated := options.Sessions.Ensure(context.Writer, context.Request)
+		if authenticated {
+			context.Redirect(http.StatusSeeOther, "/tasks")
+			return
+		}
+
+		renderLogin(context, http.StatusOK, csrfToken, returnTo(context.Query("return_to")), "", "")
+	}
+}
+
+func login(options Options) gin.HandlerFunc {
+	return func(context *gin.Context) {
+		limitFormBody(context)
+		csrfToken := context.PostForm("csrf_token")
+		returnPath := returnTo(context.PostForm("return_to"))
+		username := context.PostForm("username")
+		password := context.PostForm("password")
+
+		if _, ok := options.Sessions.VerifyCSRF(context.Request, csrfToken); !ok {
+			newCSRF, _ := options.Sessions.Ensure(context.Writer, context.Request)
+			renderLogin(context, http.StatusForbidden, newCSRF, returnPath, "", "请求已过期，请重新登录。")
+			return
+		}
+
+		usernameMatches := subtle.ConstantTimeCompare([]byte(options.AdminUsername), []byte(username)) == 1
+		passwordMatches := bcrypt.CompareHashAndPassword([]byte(options.AdminPasswordBcrypt), []byte(password)) == nil
+		if !usernameMatches || !passwordMatches {
+			csrf, _ := options.Sessions.Ensure(context.Writer, context.Request)
+			renderLogin(context, http.StatusUnauthorized, csrf, returnPath, "", "账号或密码不正确，请检查后重试。")
+			return
+		}
+
+		options.Sessions.RotateAuthenticated(context.Writer, context.Request)
+		context.Redirect(http.StatusSeeOther, returnPath)
+	}
+}
+
+func logout(options Options) gin.HandlerFunc {
+	return func(context *gin.Context) {
+		limitFormBody(context)
+		authenticated, ok := options.Sessions.VerifyCSRF(context.Request, context.PostForm("csrf_token"))
+		if !ok || !authenticated {
+			context.Status(http.StatusForbidden)
+			return
+		}
+
+		options.Sessions.Logout(context.Writer, context.Request)
+		context.Redirect(http.StatusSeeOther, "/login")
+	}
+}
+
+func tasksPage(options Options) gin.HandlerFunc {
+	return func(context *gin.Context) {
+		csrfToken, authenticated := options.Sessions.Ensure(context.Writer, context.Request)
+		if !authenticated {
+			context.Redirect(http.StatusSeeOther, "/login?return_to="+url.QueryEscape(context.Request.URL.RequestURI()))
+			return
+		}
+
+		context.Header("Content-Type", "text/html; charset=utf-8")
+		if err := webui.RenderTasks(context.Writer, webui.TasksData{CSRFToken: csrfToken}); err != nil {
+			_ = context.Error(err)
+		}
+	}
+}
+
+func renderLogin(context *gin.Context, status int, csrfToken, returnPath, username, message string) {
+	context.Header("Content-Type", "text/html; charset=utf-8")
+	context.Status(status)
+	if err := webui.RenderLogin(context.Writer, webui.LoginData{
+		CSRFToken: csrfToken,
+		ReturnTo:  returnPath,
+		Username:  username,
+		Error:     message,
+	}); err != nil {
+		_ = context.Error(err)
+	}
+}
+
+func limitFormBody(context *gin.Context) {
+	context.Request.Body = http.MaxBytesReader(context.Writer, context.Request.Body, maxFormBytes)
+}
+
+func returnTo(value string) string {
+	if value == "/tasks" || strings.HasPrefix(value, "/tasks/") || strings.HasPrefix(value, "/tasks?") {
+		if strings.Contains(value, "\\") || strings.Contains(value, "%") || strings.HasPrefix(value, "//") {
+			return "/tasks"
+		}
+		parsed, err := url.ParseRequestURI(value)
+		if err == nil && parsed.IsAbs() == false && parsed.Host == "" && hasSafeTaskPath(parsed.Path) {
+			return value
+		}
+	}
+
+	return "/tasks"
+}
+
+func hasSafeTaskPath(path string) bool {
+	for _, segment := range strings.Split(path, "/") {
+		if segment == "." || segment == ".." {
+			return false
+		}
+	}
+	return true
 }

admin/internal/server/router_test.go

@@ -3,26 +3,291 @@ package server_test
 import (
 	"net/http"
 	"net/http/httptest"
+	"net/url"
+	"regexp"
+	"strings"
 	"testing"
 
+	"cmbuyer/admin/internal/auth"
 	"cmbuyer/admin/internal/server"
+
+	"github.com/gin-gonic/gin"
+	"golang.org/x/crypto/bcrypt"
 )
 
-func TestHealthz(t *testing.T) {
+var csrfPattern = regexp.MustCompile(`name="csrf_token" value="([^"]+)"`)
+
+func TestHealthzIsPublic(t *testing.T) {
+	router, _ := newRouter(t)
 	request := httptest.NewRequest(http.MethodGet, "/healthz", nil)
 	response := httptest.NewRecorder()
 
-	server.NewRouter().ServeHTTP(response, request)
+	router.ServeHTTP(response, request)
 
 	if response.Code != http.StatusOK {
 		t.Fatalf("healthz status = %d, want %d", response.Code, http.StatusOK)
 	}
-
 	if contentType := response.Header().Get("Content-Type"); contentType != "application/json; charset=utf-8" {
 		t.Fatalf("healthz content type = %q, want application/json; charset=utf-8", contentType)
 	}
-
 	if body := response.Body.String(); body != "{\"status\":\"ok\"}" {
 		t.Fatalf("healthz body = %q, want {\"status\":\"ok\"}", body)
 	}
+	assertSecurityHeaders(t, response)
+}
+
+func TestTasksRequiresLoginAndBlocksOpenRedirects(t *testing.T) {
+	router, _ := newRouter(t)
+
+	tasks := serve(router, http.MethodGet, "/tasks", nil, nil)
+	if tasks.Code != http.StatusSeeOther {
+		t.Fatalf("GET /tasks status = %d, want %d", tasks.Code, http.StatusSeeOther)
+	}
+	if location := tasks.Header().Get("Location"); location != "/login?return_to=%2Ftasks" {
+		t.Fatalf("GET /tasks location = %q, want login return path", location)
+	}
+
+	for _, target := range []string{"https://example.invalid", "//example.invalid", `\\example.invalid`, "/other", "/tasks/..", "/tasks/../other", "/tasks/%2e%2e", "%2F%2Fevil.invalid", "%252F%252Fevil.invalid"} {
+		response := serve(router, http.MethodGet, "/login?return_to="+url.QueryEscape(target), nil, nil)
+		if response.Code != http.StatusOK {
+			t.Fatalf("GET /login return_to=%q status = %d, want 200", target, response.Code)
+		}
+		if strings.Contains(response.Body.String(), target) || !strings.Contains(response.Body.String(), `name="return_to" value="/tasks"`) {
+			t.Fatalf("GET /login accepted unsafe return_to %q", target)
+		}
+	}
+
+	encodedPath := serve(router, http.MethodGet, "/login?return_to=%2Ftasks%252F..", nil, nil)
+	if !strings.Contains(encodedPath.Body.String(), `name="return_to" value="/tasks"`) {
+		t.Fatal("encoded parent path was accepted as return_to")
+	}
+	encodedQuery := serve(router, http.MethodGet, "/login?return_to=%2Ftasks%3Fnext%3D%252Ftasks%252F..", nil, nil)
+	if !strings.Contains(encodedQuery.Body.String(), `name="return_to" value="/tasks"`) {
+		t.Fatal("encoded query bypass was accepted as return_to")
+	}
+}
+
+func TestLoginRotatesSessionAndCSRF(t *testing.T) {
+	router, _ := newRouter(t)
+	initial := serve(router, http.MethodGet, "/login?return_to=%2Ftasks%3Fview%3Dmine", nil, nil)
+	oldCookie := sessionCookie(t, initial)
+	oldCSRF := csrfToken(t, initial.Body.String())
+
+	login := serve(router, http.MethodPost, "/login", url.Values{
+		"csrf_token": {oldCSRF},
+		"return_to":  {"/tasks?view=mine"},
+		"username":   {"admin"},
+		"password":   {"test-password"},
+	}, oldCookie)
+	if login.Code != http.StatusSeeOther || login.Header().Get("Location") != "/tasks?view=mine" {
+		t.Fatalf("successful login = (%d, %q), want 303 /tasks?view=mine", login.Code, login.Header().Get("Location"))
+	}
+	newCookie := sessionCookie(t, login)
+	if newCookie.Value == oldCookie.Value {
+		t.Fatal("successful login reused the anonymous session cookie")
+	}
+
+	tasks := serve(router, http.MethodGet, "/tasks", nil, newCookie)
+	if tasks.Code != http.StatusOK {
+		t.Fatalf("GET /tasks after login status = %d, want 200", tasks.Code)
+	}
+	if newCSRF := csrfToken(t, tasks.Body.String()); newCSRF == oldCSRF {
+		t.Fatal("successful login reused the anonymous CSRF token")
+	}
+	for _, forbidden := range []string{"建单", "试选", "拼多多", "规格", "单价", "证据"} {
+		if strings.Contains(tasks.Body.String(), forbidden) {
+			t.Fatalf("task shell must not expose deferred feature content %q", forbidden)
+		}
+	}
+	assertSecurityHeaders(t, initial)
+	assertSecurityHeaders(t, tasks)
+}
+
+func TestLoginPageIncludesAccessibleFormBasics(t *testing.T) {
+	router, _ := newRouter(t)
+	page := serve(router, http.MethodGet, "/login", nil, nil)
+	body := page.Body.String()
+	for _, want := range []string{
+		`<label for="username">`,
+		`<label for="password">`,
+		`autocomplete="username"`,
+		`autocomplete="current-password"`,
+		`min-height:44px`,
+		`:focus-visible`,
+		`prefers-reduced-motion`,
+	} {
+		if !strings.Contains(body, want) {
+			t.Fatalf("login page is missing %q", want)
+		}
+	}
+	if strings.Contains(body, "http://") || strings.Contains(body, "https://") || strings.Contains(body, "<script") {
+		t.Fatal("login page must not load external resources or require client-side JavaScript")
+	}
+
+	failure := serve(router, http.MethodPost, "/login", url.Values{
+		"csrf_token": {csrfToken(t, body)},
+		"username":   {"admin"},
+		"password":   {"wrong"},
+	}, sessionCookie(t, page))
+	if !strings.Contains(failure.Body.String(), `role="alert"`) {
+		t.Fatal("login failure must announce its error")
+	}
+}
+
+func TestLoginCSRFAndCredentialFailuresAreSafe(t *testing.T) {
+	router, _ := newRouter(t)
+	page := serve(router, http.MethodGet, "/login", nil, nil)
+	cookie := sessionCookie(t, page)
+
+	withoutCSRF := serve(router, http.MethodPost, "/login", url.Values{
+		"username": {"admin"},
+		"password": {"test-password"},
+	}, cookie)
+	if withoutCSRF.Code != http.StatusForbidden || !strings.Contains(withoutCSRF.Body.String(), "请求已过期") {
+		t.Fatalf("login without CSRF = (%d, %q), want rejected form", withoutCSRF.Code, withoutCSRF.Body.String())
+	}
+
+	page = serve(router, http.MethodGet, "/login", nil, cookie)
+	badCredentials := serve(router, http.MethodPost, "/login", url.Values{
+		"csrf_token": {csrfToken(t, page.Body.String())},
+		"username":   {"unknown"},
+		"password":   {"wrong"},
+	}, cookie)
+	if badCredentials.Code != http.StatusUnauthorized {
+		t.Fatalf("login with invalid credentials status = %d, want 401", badCredentials.Code)
+	}
+	if body := badCredentials.Body.String(); !strings.Contains(body, "账号或密码不正确") || strings.Contains(body, "unknown") {
+		t.Fatalf("invalid login leaked account detail: %q", body)
+	}
+}
+
+func TestTamperedCookieCannotAccessTasks(t *testing.T) {
+	router, _ := newRouter(t)
+	page := serve(router, http.MethodGet, "/login", nil, nil)
+	cookie := sessionCookie(t, page)
+
+	tampered := *cookie
+	tampered.Value = flipCookieValue(t, cookie.Value)
+	response := serve(router, http.MethodGet, "/tasks", nil, &tampered)
+	if response.Code != http.StatusSeeOther {
+		t.Fatalf("tampered cookie status = %d, want 303", response.Code)
+	}
+
+}
+
+func assertSecurityHeaders(t *testing.T, response *httptest.ResponseRecorder) {
+	t.Helper()
+	want := map[string]string{
+		"Cache-Control":           "no-store",
+		"X-Content-Type-Options":  "nosniff",
+		"Referrer-Policy":         "no-referrer",
+		"Content-Security-Policy": "default-src 'self'; style-src 'self' 'unsafe-inline'; script-src 'none'; object-src 'none'; base-uri 'none'; frame-ancestors 'none'; form-action 'self'",
+	}
+	for name, expected := range want {
+		if got := response.Header().Get(name); got != expected {
+			t.Fatalf("%s = %q, want %q", name, got, expected)
+		}
+	}
+}
+
+func flipCookieValue(t *testing.T, value string) string {
+	t.Helper()
+	if value == "" {
+		t.Fatal("cannot tamper with an empty cookie")
+	}
+	if value[0] == 'A' {
+		return "B" + value[1:]
+	}
+	return "A" + value[1:]
+}
+
+func TestLogoutRequiresCSRFAndRevokesSession(t *testing.T) {
+	router, _ := newRouter(t)
+	loginPage := serve(router, http.MethodGet, "/login", nil, nil)
+	loginCookie := sessionCookie(t, loginPage)
+	login := serve(router, http.MethodPost, "/login", url.Values{
+		"csrf_token": {csrfToken(t, loginPage.Body.String())},
+		"username":   {"admin"},
+		"password":   {"test-password"},
+	}, loginCookie)
+	authenticatedCookie := sessionCookie(t, login)
+
+	missingCSRF := serve(router, http.MethodPost, "/logout", url.Values{}, authenticatedCookie)
+	if missingCSRF.Code != http.StatusForbidden {
+		t.Fatalf("logout without CSRF status = %d, want 403", missingCSRF.Code)
+	}
+
+	tasks := serve(router, http.MethodGet, "/tasks", nil, authenticatedCookie)
+	logout := serve(router, http.MethodPost, "/logout", url.Values{
+		"csrf_token": {csrfToken(t, tasks.Body.String())},
+	}, authenticatedCookie)
+	if logout.Code != http.StatusSeeOther || logout.Header().Get("Location") != "/login" {
+		t.Fatalf("logout = (%d, %q), want 303 /login", logout.Code, logout.Header().Get("Location"))
+	}
+	if cookie := sessionCookie(t, logout); cookie.MaxAge >= 0 {
+		t.Fatalf("logout cookie MaxAge = %d, want a deletion cookie", cookie.MaxAge)
+	}
+
+	reused := serve(router, http.MethodGet, "/tasks", nil, authenticatedCookie)
+	if reused.Code != http.StatusSeeOther {
+		t.Fatalf("revoked session status = %d, want 303", reused.Code)
+	}
+}
+
+func newRouter(t *testing.T) (*gin.Engine, *auth.Manager) {
+	t.Helper()
+	gin.SetMode(gin.TestMode)
+	hash, err := bcrypt.GenerateFromPassword([]byte("test-password"), bcrypt.MinCost)
+	if err != nil {
+		t.Fatalf("generate bcrypt hash: %v", err)
+	}
+	manager := auth.NewManager([]byte(strings.Repeat("s", 32)), false)
+	router, err := server.NewRouter(server.Options{
+		AdminUsername:       "admin",
+		AdminPasswordBcrypt: string(hash),
+		Sessions:            manager,
+	})
+	if err != nil {
+		t.Fatalf("NewRouter: %v", err)
+	}
+	return router, manager
+}
+
+func serve(router http.Handler, method, target string, form url.Values, cookie *http.Cookie) *httptest.ResponseRecorder {
+	var body *strings.Reader
+	if form == nil {
+		body = strings.NewReader("")
+	} else {
+		body = strings.NewReader(form.Encode())
+	}
+	request := httptest.NewRequest(method, target, body)
+	if form != nil {
+		request.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	}
+	if cookie != nil {
+		request.AddCookie(cookie)
+	}
+	response := httptest.NewRecorder()
+	router.ServeHTTP(response, request)
+	return response
+}
+
+func sessionCookie(t *testing.T, response *httptest.ResponseRecorder) *http.Cookie {
+	t.Helper()
+	for _, cookie := range response.Result().Cookies() {
+		if cookie.Name == auth.CookieName {
+			return cookie
+		}
+	}
+	t.Fatalf("response did not set %s cookie", auth.CookieName)
+	return nil
+}
+
+func csrfToken(t *testing.T, body string) string {
+	t.Helper()
+	matches := csrfPattern.FindStringSubmatch(body)
+	if len(matches) != 2 || matches[1] == "" {
+		t.Fatalf("no CSRF token in response body: %q", body)
+	}
+	return matches[1]
 }

admin/internal/transport/webui/templates/login.html

@@ -0,0 +1,63 @@
+{{define "login.html"}}
+<!doctype html>
+<html lang="zh-CN">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>登录 · 采购服务</title>
+  <style>
+    :root { color-scheme: light; --bg:#f4f7fb; --surface:#fff; --text:#172033; --muted:#526079; --border:#cfd8e6; --primary:#155eef; --primary-hover:#0b4ed1; --primary-soft:#eaf1ff; --danger:#b42318; --danger-soft:#fef3f2; --focus:#ffbf47; --shadow:0 12px 30px rgba(23,32,51,.1); font-family:"Segoe UI","Microsoft YaHei UI",system-ui,sans-serif; }
+    * { box-sizing:border-box; }
+    html { min-width:320px; background:var(--bg); }
+    body { min-height:100dvh; margin:0; color:var(--text); background:var(--bg); font-size:16px; line-height:1.55; }
+    button,input { font:inherit; }
+    :focus-visible { outline:3px solid var(--focus); outline-offset:3px; }
+    .skip-link { position:fixed; z-index:10; top:8px; left:8px; padding:10px 14px; color:#fff; background:var(--text); transform:translateY(-160%); }
+    .skip-link:focus { transform:translateY(0); }
+    main { display:grid; min-height:100dvh; place-items:center; padding:24px 16px; }
+    .card { width:min(100%,440px); padding:32px; border:1px solid var(--border); border-radius:14px; background:var(--surface); box-shadow:var(--shadow); }
+    .brand { display:flex; align-items:center; gap:10px; margin:0 0 24px; font-size:1rem; font-weight:700; }
+    .brand-mark { display:grid; width:32px; height:32px; place-items:center; border-radius:8px; color:#fff; background:var(--primary); font-size:.82rem; }
+    h1 { margin:0; font-size:clamp(1.6rem,5vw,2rem); line-height:1.25; }
+    .intro { margin:8px 0 24px; color:var(--muted); }
+    .field { margin-top:16px; }
+    label { display:block; margin-bottom:6px; font-weight:700; }
+    input { width:100%; min-height:44px; padding:10px 12px; border:1px solid #9ba9bc; border-radius:8px; color:var(--text); background:#fff; }
+    input[aria-invalid="true"] { border-color:var(--danger); box-shadow:0 0 0 1px var(--danger); }
+    .hint { margin:5px 0 0; color:var(--muted); font-size:.875rem; }
+    .error { margin:0 0 18px; padding:12px 14px; border-left:4px solid var(--danger); border-radius:6px; color:var(--danger); background:var(--danger-soft); font-weight:650; }
+    .submit { width:100%; min-height:44px; margin-top:24px; padding:10px 16px; border:1px solid transparent; border-radius:8px; color:#fff; background:var(--primary); font-weight:700; cursor:pointer; transition:background-color 180ms ease-out; }
+    .submit:hover { background:var(--primary-hover); }
+    .notice { margin:20px 0 0; padding:12px 14px; border:1px solid #b9cffc; border-radius:8px; color:#29466f; background:var(--primary-soft); font-size:.9rem; }
+    @media (max-width:420px) { main { padding-inline:12px; } .card { padding:24px 16px; } }
+    @media (prefers-reduced-motion:reduce) { *,*::before,*::after { transition-duration:.01ms !important; animation-duration:.01ms !important; } }
+  </style>
+</head>
+<body>
+  <a class="skip-link" href="#main">跳到主要内容</a>
+  <main id="main">
+    <section class="card" aria-labelledby="login-title">
+      <p class="brand"><span class="brand-mark" aria-hidden="true">采</span><span>采购服务</span></p>
+      <h1 id="login-title">管理端登录</h1>
+      <p class="intro">登录后进入采购任务工作台。设备身份不能使用此入口。</p>
+      {{if .Error}}<p class="error" role="alert">{{.Error}}</p>{{end}}
+      <form method="post" action="/login">
+        <input type="hidden" name="csrf_token" value="{{.CSRFToken}}">
+        <input type="hidden" name="return_to" value="{{.ReturnTo}}">
+        <div class="field">
+          <label for="username">账号</label>
+          <input id="username" name="username" type="text" value="{{.Username}}" autocomplete="username" required aria-invalid="{{if .Error}}true{{else}}false{{end}}" aria-describedby="username-hint">
+          <p class="hint" id="username-hint">使用采购管理员账号登录。</p>
+        </div>
+        <div class="field">
+          <label for="password">密码</label>
+          <input id="password" name="password" type="password" autocomplete="current-password" required aria-invalid="{{if .Error}}true{{else}}false{{end}}">
+        </div>
+        <button class="submit" type="submit">登录并继续</button>
+      </form>
+      <p class="notice">系统只创建待付款订单，付款始终由人完成。</p>
+    </section>
+  </main>
+</body>
+</html>
+{{end}}

admin/internal/transport/webui/templates/tasks.html

@@ -0,0 +1,27 @@
+{{define "tasks.html"}}
+<!doctype html>
+<html lang="zh-CN">
+<head>
+  <meta charset="utf-8">
+  <meta name="viewport" content="width=device-width, initial-scale=1">
+  <title>采购任务 · 采购服务</title>
+  <style>
+    :root { color-scheme:light; --bg:#f4f7fb; --surface:#fff; --text:#172033; --muted:#526079; --border:#cfd8e6; --primary:#155eef; --focus:#ffbf47; font-family:"Segoe UI","Microsoft YaHei UI",system-ui,sans-serif; }
+    * { box-sizing:border-box; } body { min-height:100dvh; margin:0; color:var(--text); background:var(--bg); font-size:16px; line-height:1.55; } button { font:inherit; } :focus-visible { outline:3px solid var(--focus); outline-offset:3px; }
+    .skip-link { position:fixed; z-index:10; top:8px; left:8px; padding:10px 14px; color:#fff; background:var(--text); transform:translateY(-160%); } .skip-link:focus { transform:translateY(0); }
+    header { display:flex; min-height:64px; align-items:center; justify-content:space-between; gap:16px; padding:10px clamp(16px,4vw,40px); border-bottom:1px solid var(--border); background:var(--surface); }
+    .brand { display:flex; align-items:center; gap:10px; font-weight:700; } .brand-mark { display:grid; width:32px; height:32px; place-items:center; border-radius:8px; color:#fff; background:var(--primary); font-size:.82rem; }
+    .logout { min-height:44px; padding:8px 14px; border:1px solid var(--border); border-radius:8px; color:var(--text); background:var(--surface); font-weight:700; cursor:pointer; }
+    main { width:min(100% - 32px,760px); margin:48px auto; padding:32px; border:1px solid var(--border); border-radius:14px; background:var(--surface); }
+    h1 { margin:0; font-size:clamp(1.5rem,5vw,2rem); } p { color:var(--muted); } .notice { margin-top:24px; padding:14px; border-left:4px solid var(--primary); border-radius:6px; background:#eaf1ff; color:#29466f; }
+    @media (max-width:420px) { main { width:calc(100% - 24px); margin:24px auto; padding:24px 16px; } }
+    @media (prefers-reduced-motion:reduce) { *,*::before,*::after { transition-duration:.01ms !important; animation-duration:.01ms !important; } }
+  </style>
+</head>
+<body>
+  <a class="skip-link" href="#main">跳到主要内容</a>
+  <header><div class="brand"><span class="brand-mark" aria-hidden="true">采</span><span>采购服务</span></div><form method="post" action="/logout"><input type="hidden" name="csrf_token" value="{{.CSRFToken}}"><button class="logout" type="submit">退出登录</button></form></header>
+  <main id="main"><h1>采购任务</h1><p>任务功能正在准备中。</p><p class="notice">当前页面仅用于验证管理员会话。</p></main>
+</body>
+</html>
+{{end}}

admin/internal/transport/webui/webui.go

@@ -0,0 +1,36 @@
+// Package webui 渲染采购服务当前可用的服务端页面。
+package webui
+
+import (
+	"embed"
+	"html/template"
+	"io"
+)
+
+//go:embed templates/*.html
+var templateFiles embed.FS
+
+var templates = template.Must(template.New("webui").ParseFS(templateFiles, "templates/*.html"))
+
+// LoginData 是登录页面所需的非敏感展示数据。
+type LoginData struct {
+	CSRFToken string
+	ReturnTo  string
+	Username  string
+	Error     string
+}
+
+// TasksData 是当前受保护任务空壳所需的数据。任务字段将在后续任务实现。
+type TasksData struct {
+	CSRFToken string
+}
+
+// RenderLogin 写入登录页。
+func RenderLogin(writer io.Writer, data LoginData) error {
+	return templates.ExecuteTemplate(writer, "login.html", data)
+}
+
+// RenderTasks 写入登录后的受保护空壳。
+func RenderTasks(writer io.Writer, data TasksData) error {
+	return templates.ExecuteTemplate(writer, "tasks.html", data)
+}