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Migrate CSRF, web templates, session cookies, and snapshot to mcdsl

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CSRF: Replace local csrfProtect with mcdsl/csrf.Protect. Delete
internal/webserver/csrf.go.

Web: Replace renderTemplate with web.RenderTemplate + csrf.TemplateFunc.
Replace extractCookie with web.GetSessionToken. Replace manual session
cookie SetCookie with web.SetSessionCookie.

Snapshot: Replace local sqliteBackup with mcdsl/db.Snapshot.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
This commit is contained in:
Kyle Isom
2026-03-26 14:14:11 -07:00
parent 2a927e5359
commit 806f63957b
6 changed files with 41 additions and 228 deletions
Download Patch File Download Diff File Expand all files Collapse all files

2
internal/webserver/cert_detail_test.go
View File

@@ -307,7 +307,7 @@ func newTestWebServer(t *testing.T, vault vaultBackend) *WebServer {
vault: vault,
logger: slog.Default(),
staticFS: staticFS,
csrf: newCSRFProtect(),
csrf: newTestCSRF(t),
}
}

119
internal/webserver/csrf.go
View File

@@ -1,119 +0,0 @@
package webserver
import (
"crypto/hmac"
"crypto/rand"
"crypto/sha256"
"encoding/base64"
"fmt"
"net/http"
"strings"
"sync"
)
const (
csrfCookieName = "metacrypt_csrf"
csrfFieldName = "csrf_token"
csrfTokenLen = 32
)
// csrfProtect provides CSRF protection using the signed double-submit cookie
// pattern. A random secret is generated at startup. CSRF tokens are an HMAC of
// a random nonce, sent as both a cookie and a hidden form field. On POST the
// middleware verifies that the form field matches the cookie's HMAC.
type csrfProtect struct {
secret []byte
once sync.Once
}
func newCSRFProtect() *csrfProtect {
secret := make([]byte, 32)
if _, err := rand.Read(secret); err != nil {
panic("csrf: failed to generate secret: " + err.Error())
}
return &csrfProtect{secret: secret}
}
// generateToken creates a new CSRF token: base64(nonce) + "." + base64(hmac(nonce)).
func (c *csrfProtect) generateToken() (string, error) {
nonce := make([]byte, csrfTokenLen)
if _, err := rand.Read(nonce); err != nil {
return "", fmt.Errorf("csrf: generate nonce: %w", err)
}
nonceB64 := base64.RawURLEncoding.EncodeToString(nonce)
mac := hmac.New(sha256.New, c.secret)
mac.Write(nonce)
sigB64 := base64.RawURLEncoding.EncodeToString(mac.Sum(nil))
return nonceB64 + "." + sigB64, nil
}
// validToken checks that a token has a valid HMAC signature.
func (c *csrfProtect) validToken(token string) bool {
parts := strings.SplitN(token, ".", 2)
if len(parts) != 2 {
return false
}
nonce, err := base64.RawURLEncoding.DecodeString(parts[0])
if err != nil || len(nonce) != csrfTokenLen {
return false
}
sig, err := base64.RawURLEncoding.DecodeString(parts[1])
if err != nil {
return false
}
mac := hmac.New(sha256.New, c.secret)
mac.Write(nonce)
return hmac.Equal(mac.Sum(nil), sig)
}
// setToken generates a new CSRF token, sets it as a cookie, and returns it
// for embedding in a form.
func (c *csrfProtect) setToken(w http.ResponseWriter) string {
token, err := c.generateToken()
if err != nil {
return ""
}
http.SetCookie(w, &http.Cookie{
Name: csrfCookieName,
Value: token,
Path: "/",
HttpOnly: true,
Secure: true,
SameSite: http.SameSiteStrictMode,
})
return token
}
// middleware returns an HTTP middleware that enforces CSRF validation on
// mutation requests (POST, PUT, PATCH, DELETE). GET/HEAD/OPTIONS are passed
// through. The HTMX hx-post for /v1/seal is excluded since it hits the API
// server directly and uses token auth, not cookies.
func (c *csrfProtect) middleware(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
switch r.Method {
case http.MethodGet, http.MethodHead, http.MethodOptions:
next.ServeHTTP(w, r)
return
}
// Read token from form field (works for both regular forms and
// multipart forms since ParseForm/ParseMultipartForm will have
// been called or the field is available via FormValue).
formToken := r.FormValue(csrfFieldName)
// Read token from cookie.
cookie, err := r.Cookie(csrfCookieName)
if err != nil || cookie.Value == "" {
http.Error(w, "CSRF validation failed", http.StatusForbidden)
return
}
// Both tokens must be present, match each other, and be validly signed.
if formToken == "" || formToken != cookie.Value || !c.validToken(formToken) {
http.Error(w, "CSRF validation failed", http.StatusForbidden)
return
}
next.ServeHTTP(w, r)
})
}

78
internal/webserver/csrf_test.go
View File

@@ -1,44 +1,28 @@
package webserver
import (
"crypto/rand"
"net/http"
"net/http/httptest"
"net/url"
"strings"
"testing"
"git.wntrmute.dev/kyle/mcdsl/csrf"
)
func TestCSRFTokenGenerateAndValidate(t *testing.T) {
c := newCSRFProtect()
token, err := c.generateToken()
if err != nil {
t.Fatalf("generateToken: %v", err)
}
if !c.validToken(token) {
t.Fatal("valid token rejected")
}
}
func TestCSRFTokenInvalidFormats(t *testing.T) {
c := newCSRFProtect()
for _, bad := range []string{"", "nodot", "a.b.c", "abc.def"} {
if c.validToken(bad) {
t.Errorf("should reject %q", bad)
}
}
}
func TestCSRFTokenCrossSecret(t *testing.T) {
c1 := newCSRFProtect()
c2 := newCSRFProtect()
token, _ := c1.generateToken()
if c2.validToken(token) {
t.Fatal("token from different secret should be rejected")
func newTestCSRF(t *testing.T) *csrf.Protect {
t.Helper()
secret := make([]byte, 32)
if _, err := rand.Read(secret); err != nil {
t.Fatal(err)
}
return csrf.New(secret, "metacrypt_csrf", "csrf_token")
}
func TestCSRFMiddlewareAllowsGET(t *testing.T) {
c := newCSRFProtect()
handler := c.middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
c := newTestCSRF(t)
handler := c.Middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
}))
req := httptest.NewRequest(http.MethodGet, "/", nil)
@@ -50,8 +34,8 @@ func TestCSRFMiddlewareAllowsGET(t *testing.T) {
}
func TestCSRFMiddlewareBlocksPOSTWithoutToken(t *testing.T) {
c := newCSRFProtect()
handler := c.middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
c := newTestCSRF(t)
handler := c.Middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
}))
req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader("foo=bar"))
@@ -64,17 +48,20 @@ func TestCSRFMiddlewareBlocksPOSTWithoutToken(t *testing.T) {
}
func TestCSRFMiddlewareAllowsPOSTWithValidToken(t *testing.T) {
c := newCSRFProtect()
token, _ := c.generateToken()
c := newTestCSRF(t)
handler := c.middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
// Generate a token via SetToken (writes cookie to response).
rec := httptest.NewRecorder()
token := c.SetToken(rec)
handler := c.Middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
}))
body := csrfFieldName + "=" + token
body := "csrf_token=" + url.QueryEscape(token)
req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(body))
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
req.AddCookie(&http.Cookie{Name: csrfCookieName, Value: token})
req.AddCookie(&http.Cookie{Name: "metacrypt_csrf", Value: token})
w := httptest.NewRecorder()
handler.ServeHTTP(w, req)
@@ -82,24 +69,3 @@ func TestCSRFMiddlewareAllowsPOSTWithValidToken(t *testing.T) {
t.Fatalf("POST with valid CSRF token should pass, got %d", w.Code)
}
}
func TestCSRFMiddlewareRejectsMismatch(t *testing.T) {
c := newCSRFProtect()
token1, _ := c.generateToken()
token2, _ := c.generateToken()
handler := c.middleware(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.WriteHeader(http.StatusOK)
}))
body := csrfFieldName + "=" + token1
req := httptest.NewRequest(http.MethodPost, "/", strings.NewReader(body))
req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
req.AddCookie(&http.Cookie{Name: csrfCookieName, Value: token2})
w := httptest.NewRecorder()
handler.ServeHTTP(w, req)
if w.Code != http.StatusForbidden {
t.Fatalf("POST with mismatched tokens should be forbidden, got %d", w.Code)
}
}

11
internal/webserver/routes.go
View File

@@ -16,6 +16,8 @@ import (
"github.com/go-chi/chi/v5"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
"git.wntrmute.dev/kyle/mcdsl/web"
)
// splitLines splits a newline-delimited string into non-empty trimmed lines.
@@ -224,14 +226,7 @@ func (ws *WebServer) handleLogin(w http.ResponseWriter, r *http.Request) {
ws.renderTemplate(w, "login.html", map[string]interface{}{"Error": "Invalid credentials"})
return
}
http.SetCookie(w, &http.Cookie{
Name: "metacrypt_token",
Value: token,
Path: "/",
HttpOnly: true,
Secure: true,
SameSite: http.SameSiteStrictMode,
})
web.SetSessionCookie(w, "metacrypt_token", token)
http.Redirect(w, r, "/dashboard", http.StatusFound)
default:
http.Error(w, "method not allowed", http.StatusMethodNotAllowed)

46
internal/webserver/server.go
View File

@@ -4,9 +4,9 @@ package webserver
import (
"context"
"crypto/rand"
"crypto/tls"
"fmt"
"html/template"
"io/fs"
"log/slog"
"net/http"
@@ -16,6 +16,8 @@ import (
"github.com/go-chi/chi/v5"
mcdslauth "git.wntrmute.dev/kyle/mcdsl/auth"
"git.wntrmute.dev/kyle/mcdsl/csrf"
"git.wntrmute.dev/kyle/mcdsl/web"
"git.wntrmute.dev/kyle/metacrypt/internal/config"
webui "git.wntrmute.dev/kyle/metacrypt/web"
)
@@ -116,7 +118,7 @@ type WebServer struct {
logger *slog.Logger
httpSrv *http.Server
staticFS fs.FS
csrf *csrfProtect
csrf *csrf.Protect
tgzCache sync.Map // key: UUID string → *tgzEntry
userCache sync.Map // key: UUID string → *cachedUsername
}
@@ -154,12 +156,17 @@ func New(cfg *config.Config, logger *slog.Logger) (*WebServer, error) {
return nil, fmt.Errorf("webserver: static FS: %w", err)
}
secret := make([]byte, 32)
if _, err := rand.Read(secret); err != nil {
return nil, fmt.Errorf("webserver: generate CSRF secret: %w", err)
}
ws := &WebServer{
cfg: cfg,
vault: vault,
logger: logger,
staticFS: staticFS,
csrf: newCSRFProtect(),
csrf: csrf.New(secret, "metacrypt_csrf", "csrf_token"),
}
if tok := cfg.MCIAS.ServiceToken; tok != "" {
@@ -220,7 +227,7 @@ func (lw *loggingResponseWriter) Unwrap() http.ResponseWriter {
func (ws *WebServer) Start() error {
r := chi.NewRouter()
r.Use(ws.loggingMiddleware)
r.Use(ws.csrf.middleware)
r.Use(ws.csrf.Middleware)
ws.registerRoutes(r)
ws.httpSrv = &http.Server{
@@ -259,36 +266,9 @@ func (ws *WebServer) Shutdown(ctx context.Context) error {
}
func (ws *WebServer) renderTemplate(w http.ResponseWriter, name string, data interface{}) {
csrfToken := ws.csrf.setToken(w)
funcMap := template.FuncMap{
"csrfField": func() template.HTML {
return template.HTML(fmt.Sprintf(
`<input type="hidden" name="%s" value="%s">`,
csrfFieldName, template.HTMLEscapeString(csrfToken),
))
},
}
tmpl, err := template.New("").Funcs(funcMap).ParseFS(webui.FS,
"templates/layout.html",
"templates/"+name,
)
if err != nil {
ws.logger.Error("parse template", "name", name, "error", err)
http.Error(w, "internal server error", http.StatusInternalServerError)
return
}
w.Header().Set("Content-Type", "text/html; charset=utf-8")
if err := tmpl.ExecuteTemplate(w, "layout", data); err != nil {
ws.logger.Error("execute template", "name", name, "error", err)
}
web.RenderTemplate(w, webui.FS, name, data, ws.csrf.TemplateFunc(w))
}
func extractCookie(r *http.Request) string {
c, err := r.Cookie("metacrypt_token")
if err != nil {
return ""
}
return c.Value
return web.GetSessionToken(r, "metacrypt_token")
}