Files
nidus/internal/auth/middleware.go
T
arnefandCopilot b4644bc590 Fix WebDAV/CalDAV/CardDAV bugs, drop username from URLs, harden concurrency
- Root handler now only serves the welcome page for GET/HEAD; all other
  methods (e.g. OPTIONS, PROPFIND) return 405 with an Allow header instead
  of always returning 200, fixing client capability probes and PROPFIND
  misbehavior.
- Mount /files/ properly and cache one xwebdav.Handler per authenticated
  user so its LockSystem persists across requests instead of being
  recreated per-request (which broke LOCK/UNLOCK).
- Remove the username segment from all DAV URLs (/cal/, /card/, /files/
  are now identical for every account; the acting user is always resolved
  via Basic Auth, never the path).
- Reintroduce a fixed literal "home" path segment (/cal/home/,
  /card/home/) to preserve the URL segment depth that go-webdav's
  caldav/carddav server relies on to classify resources (principal vs.
  home-set vs. collection vs. object). Removing the username had
  collapsed this depth, silently misclassifying requests and returning
  empty <multistatus> responses (DAVx5 "no resources found").
- Replace the store's single global mutex with per-user sharded locks so
  different users' requests no longer serialize against each other.
- Add auth.NewContext test helper, WebDAV handler tests
  (per-user isolation, lock persistence across requests), and a
  concurrent multi-user store test.
- Update README and copilot-instructions to document the new URL scheme
  and the go-webdav path-depth classification quirk.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-08-18 12:49:57 +02:00

110 lines
3.0 KiB
Go

package auth
import (
"context"
"log/slog"
"net/http"
"github.com/yourusername/caldav-server/internal/config"
"golang.org/x/crypto/bcrypt"
)
type contextKey string
const userContextKey contextKey = "authenticated_user"
// Middleware wraps an http.Handler with HTTP Basic Auth enforcement.
type Middleware struct {
cfg *config.Config
logger *slog.Logger
}
func NewMiddleware(cfg *config.Config, logger *slog.Logger) *Middleware {
return &Middleware{cfg: cfg, logger: logger}
}
// Wrap returns an http.Handler that requires valid Basic Auth credentials
// before delegating to next.
func (m *Middleware) Wrap(next http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
username, password, ok := r.BasicAuth()
if !ok {
m.challenge(w)
return
}
user, err := m.authenticate(username, password)
if err != nil {
m.logger.Warn("authentication failed",
"username", username,
"remote_addr", r.RemoteAddr,
"error", err)
m.challenge(w)
return
}
m.logger.Debug("authenticated request",
"username", username,
"method", r.Method,
"path", r.URL.Path)
ctx := context.WithValue(r.Context(), userContextKey, &Principal{
Username: username,
DisplayName: user.DisplayName,
Email: user.Email,
})
next.ServeHTTP(w, r.WithContext(ctx))
})
}
// challenge sends a 401 response requesting Basic Auth.
func (m *Middleware) challenge(w http.ResponseWriter) {
w.Header().Set("WWW-Authenticate", `Basic realm="`+m.cfg.Auth.Realm+`"`)
w.Header().Set("Content-Type", "text/plain; charset=utf-8")
w.WriteHeader(http.StatusUnauthorized)
_, _ = w.Write([]byte("Unauthorized"))
}
// authenticate validates username/password against config.
func (m *Middleware) authenticate(username, password string) (*config.UserConfig, error) {
user, ok := m.cfg.Users[username]
if !ok {
// constant-time comparison to avoid timing attacks
_ = bcrypt.CompareHashAndPassword([]byte("$2b$12$invalid"), []byte(password))
return nil, errUnauthorized
}
if err := bcrypt.CompareHashAndPassword([]byte(user.Password), []byte(password)); err != nil {
return nil, errUnauthorized
}
return &user, nil
}
// Principal holds the authenticated user's identity.
type Principal struct {
Username string
DisplayName string
Email string
}
// FromContext extracts the Principal from a request context.
// Returns nil if the request was not authenticated.
func FromContext(ctx context.Context) *Principal {
p, _ := ctx.Value(userContextKey).(*Principal)
return p
}
// NewContext returns a copy of ctx carrying p, retrievable via FromContext.
// This is primarily useful for tests of downstream packages that need an
// authenticated context without going through the Basic Auth handshake.
func NewContext(ctx context.Context, p *Principal) context.Context {
return context.WithValue(ctx, userContextKey, p)
}
var errUnauthorized = &authError{msg: "invalid credentials"}
type authError struct{ msg string }
func (e *authError) Error() string { return e.msg }