sftpgo-mirror/webdavd/server.go
2021-02-04 19:09:43 +01:00

346 lines
11 KiB
Go

package webdavd
import (
"context"
"crypto/tls"
"crypto/x509"
"errors"
"fmt"
"log"
"net/http"
"path"
"path/filepath"
"runtime/debug"
"strings"
"time"
"github.com/go-chi/chi/middleware"
"github.com/rs/cors"
"github.com/rs/xid"
"golang.org/x/net/webdav"
"github.com/drakkan/sftpgo/common"
"github.com/drakkan/sftpgo/dataprovider"
"github.com/drakkan/sftpgo/logger"
"github.com/drakkan/sftpgo/metrics"
"github.com/drakkan/sftpgo/utils"
)
var (
err401 = errors.New("Unauthorized")
xForwardedFor = http.CanonicalHeaderKey("X-Forwarded-For")
xRealIP = http.CanonicalHeaderKey("X-Real-IP")
)
type webDavServer struct {
config *Configuration
binding Binding
}
func (s *webDavServer) listenAndServe(compressor *middleware.Compressor) error {
handler := compressor.Handler(s)
httpServer := &http.Server{
Addr: s.binding.GetAddress(),
ReadHeaderTimeout: 30 * time.Second,
IdleTimeout: 120 * time.Second,
MaxHeaderBytes: 1 << 16, // 64KB
ErrorLog: log.New(&logger.StdLoggerWrapper{Sender: logSender}, "", 0),
}
if s.config.Cors.Enabled {
c := cors.New(cors.Options{
AllowedOrigins: s.config.Cors.AllowedOrigins,
AllowedMethods: s.config.Cors.AllowedMethods,
AllowedHeaders: s.config.Cors.AllowedHeaders,
ExposedHeaders: s.config.Cors.ExposedHeaders,
MaxAge: s.config.Cors.MaxAge,
AllowCredentials: s.config.Cors.AllowCredentials,
OptionsPassthrough: true,
})
handler = c.Handler(handler)
}
httpServer.Handler = handler
if certMgr != nil && s.binding.EnableHTTPS {
serviceStatus.Bindings = append(serviceStatus.Bindings, s.binding)
httpServer.TLSConfig = &tls.Config{
GetCertificate: certMgr.GetCertificateFunc(),
MinVersion: tls.VersionTLS12,
}
if s.binding.ClientAuthType == 1 {
httpServer.TLSConfig.ClientCAs = certMgr.GetRootCAs()
httpServer.TLSConfig.ClientAuth = tls.RequireAndVerifyClientCert
httpServer.TLSConfig.VerifyConnection = s.verifyTLSConnection
}
logger.Info(logSender, "", "starting HTTPS serving, binding: %v", s.binding.GetAddress())
return httpServer.ListenAndServeTLS("", "")
}
s.binding.EnableHTTPS = false
serviceStatus.Bindings = append(serviceStatus.Bindings, s.binding)
logger.Info(logSender, "", "starting HTTP serving, binding: %v", s.binding.GetAddress())
return httpServer.ListenAndServe()
}
func (s *webDavServer) verifyTLSConnection(state tls.ConnectionState) error {
if certMgr != nil {
var clientCrt *x509.Certificate
var clientCrtName string
if len(state.PeerCertificates) > 0 {
clientCrt = state.PeerCertificates[0]
clientCrtName = clientCrt.Subject.String()
}
if len(state.VerifiedChains) == 0 {
logger.Warn(logSender, "", "TLS connection cannot be verified: unable to get verification chain")
return errors.New("TLS connection cannot be verified: unable to get verification chain")
}
for _, verifiedChain := range state.VerifiedChains {
var caCrt *x509.Certificate
if len(verifiedChain) > 0 {
caCrt = verifiedChain[len(verifiedChain)-1]
}
if certMgr.IsRevoked(clientCrt, caCrt) {
logger.Debug(logSender, "", "tls handshake error, client certificate %#v has been revoked", clientCrtName)
return common.ErrCrtRevoked
}
}
}
return nil
}
// returns true if we have to handle a HEAD response, for a directory, ourself
func (s *webDavServer) checkRequestMethod(ctx context.Context, r *http.Request, connection *Connection) bool {
// see RFC4918, section 9.4
if r.Method == http.MethodGet || r.Method == http.MethodHead {
p := path.Clean(r.URL.Path)
info, err := connection.Stat(ctx, p)
if err == nil && info.IsDir() {
if r.Method == http.MethodHead {
return true
}
r.Method = "PROPFIND"
if r.Header.Get("Depth") == "" {
r.Header.Add("Depth", "1")
}
}
}
return false
}
// ServeHTTP implements the http.Handler interface
func (s *webDavServer) ServeHTTP(w http.ResponseWriter, r *http.Request) {
defer func() {
if r := recover(); r != nil {
logger.Error(logSender, "", "panic in ServeHTTP: %#v stack strace: %v", r, string(debug.Stack()))
http.Error(w, common.ErrGenericFailure.Error(), http.StatusInternalServerError)
}
}()
if !common.Connections.IsNewConnectionAllowed() {
logger.Log(logger.LevelDebug, common.ProtocolFTP, "", "connection refused, configured limit reached")
http.Error(w, common.ErrConnectionDenied.Error(), http.StatusServiceUnavailable)
return
}
checkRemoteAddress(r)
ipAddr := utils.GetIPFromRemoteAddress(r.RemoteAddr)
if common.IsBanned(ipAddr) {
http.Error(w, common.ErrConnectionDenied.Error(), http.StatusForbidden)
return
}
if err := common.Config.ExecutePostConnectHook(ipAddr, common.ProtocolWebDAV); err != nil {
http.Error(w, common.ErrConnectionDenied.Error(), http.StatusForbidden)
return
}
user, _, lockSystem, err := s.authenticate(r, ipAddr)
if err != nil {
w.Header().Set("WWW-Authenticate", "Basic realm=\"SFTPGo WebDAV\"")
http.Error(w, err401.Error(), http.StatusUnauthorized)
return
}
connectionID, err := s.validateUser(&user, r)
if err != nil {
updateLoginMetrics(&user, ipAddr, err)
http.Error(w, err.Error(), http.StatusForbidden)
return
}
fs, err := user.GetFilesystem(connectionID)
if err != nil {
updateLoginMetrics(&user, ipAddr, err)
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
updateLoginMetrics(&user, ipAddr, err)
ctx := context.WithValue(r.Context(), requestIDKey, connectionID)
ctx = context.WithValue(ctx, requestStartKey, time.Now())
connection := &Connection{
BaseConnection: common.NewBaseConnection(connectionID, common.ProtocolWebDAV, user, fs),
request: r,
}
common.Connections.Add(connection)
defer common.Connections.Remove(connection.GetID())
dataprovider.UpdateLastLogin(user) //nolint:errcheck
if s.checkRequestMethod(ctx, r, connection) {
w.Header().Set("Content-Type", "text/xml; charset=utf-8")
w.WriteHeader(http.StatusMultiStatus)
w.Write([]byte("")) //nolint:errcheck
return
}
handler := webdav.Handler{
FileSystem: connection,
LockSystem: lockSystem,
Logger: writeLog,
}
handler.ServeHTTP(w, r.WithContext(ctx))
}
func (s *webDavServer) authenticate(r *http.Request, ip string) (dataprovider.User, bool, webdav.LockSystem, error) {
var user dataprovider.User
var err error
username, password, ok := r.BasicAuth()
if !ok {
return user, false, nil, err401
}
result, ok := dataprovider.GetCachedWebDAVUser(username)
if ok {
cachedUser := result.(*dataprovider.CachedUser)
if cachedUser.IsExpired() {
dataprovider.RemoveCachedWebDAVUser(username)
} else {
if password != "" && cachedUser.Password == password {
return cachedUser.User, true, cachedUser.LockSystem, nil
}
updateLoginMetrics(&cachedUser.User, ip, dataprovider.ErrInvalidCredentials)
return user, false, nil, dataprovider.ErrInvalidCredentials
}
}
user, err = dataprovider.CheckUserAndPass(username, password, ip, common.ProtocolWebDAV)
if err != nil {
user.Username = username
updateLoginMetrics(&user, ip, err)
return user, false, nil, err
}
lockSystem := webdav.NewMemLS()
if password != "" {
cachedUser := &dataprovider.CachedUser{
User: user,
Password: password,
LockSystem: lockSystem,
}
if s.config.Cache.Users.ExpirationTime > 0 {
cachedUser.Expiration = time.Now().Add(time.Duration(s.config.Cache.Users.ExpirationTime) * time.Minute)
}
dataprovider.CacheWebDAVUser(cachedUser, s.config.Cache.Users.MaxSize)
if user.FsConfig.Provider != dataprovider.SFTPFilesystemProvider {
// for sftp fs check root path does nothing so don't open a useless SFTP connection
tempFs, err := user.GetFilesystem("temp")
if err == nil {
tempFs.CheckRootPath(user.Username, user.UID, user.GID)
tempFs.Close()
}
}
}
return user, false, lockSystem, nil
}
func (s *webDavServer) validateUser(user *dataprovider.User, r *http.Request) (string, error) {
connID := xid.New().String()
connectionID := fmt.Sprintf("%v_%v", common.ProtocolWebDAV, connID)
if !filepath.IsAbs(user.HomeDir) {
logger.Warn(logSender, connectionID, "user %#v has an invalid home dir: %#v. Home dir must be an absolute path, login not allowed",
user.Username, user.HomeDir)
return connID, fmt.Errorf("cannot login user with invalid home dir: %#v", user.HomeDir)
}
if utils.IsStringInSlice(common.ProtocolWebDAV, user.Filters.DeniedProtocols) {
logger.Debug(logSender, connectionID, "cannot login user %#v, protocol DAV is not allowed", user.Username)
return connID, fmt.Errorf("Protocol DAV is not allowed for user %#v", user.Username)
}
if !user.IsLoginMethodAllowed(dataprovider.LoginMethodPassword, nil) {
logger.Debug(logSender, connectionID, "cannot login user %#v, password login method is not allowed", user.Username)
return connID, fmt.Errorf("Password login method is not allowed for user %#v", user.Username)
}
if user.MaxSessions > 0 {
activeSessions := common.Connections.GetActiveSessions(user.Username)
if activeSessions >= user.MaxSessions {
logger.Debug(logSender, connID, "authentication refused for user: %#v, too many open sessions: %v/%v", user.Username,
activeSessions, user.MaxSessions)
return connID, fmt.Errorf("too many open sessions: %v", activeSessions)
}
}
if dataprovider.GetQuotaTracking() > 0 && user.HasOverlappedMappedPaths() {
logger.Debug(logSender, connectionID, "cannot login user %#v, overlapping mapped folders are allowed only with quota tracking disabled",
user.Username)
return connID, errors.New("overlapping mapped folders are allowed only with quota tracking disabled")
}
if !user.IsLoginFromAddrAllowed(r.RemoteAddr) {
logger.Debug(logSender, connectionID, "cannot login user %#v, remote address is not allowed: %v", user.Username, r.RemoteAddr)
return connID, fmt.Errorf("Login for user %#v is not allowed from this address: %v", user.Username, r.RemoteAddr)
}
return connID, nil
}
func writeLog(r *http.Request, err error) {
scheme := "http"
if r.TLS != nil {
scheme = "https"
}
fields := map[string]interface{}{
"remote_addr": r.RemoteAddr,
"proto": r.Proto,
"method": r.Method,
"user_agent": r.UserAgent(),
"uri": fmt.Sprintf("%s://%s%s", scheme, r.Host, r.RequestURI)}
if reqID, ok := r.Context().Value(requestIDKey).(string); ok {
fields["request_id"] = reqID
}
if reqStart, ok := r.Context().Value(requestStartKey).(time.Time); ok {
fields["elapsed_ms"] = time.Since(reqStart).Nanoseconds() / 1000000
}
logger.GetLogger().Info().
Timestamp().
Str("sender", logSender).
Fields(fields).
Err(err).
Send()
}
func checkRemoteAddress(r *http.Request) {
if common.Config.ProxyProtocol != 0 {
return
}
var ip string
if xrip := r.Header.Get(xRealIP); xrip != "" {
ip = xrip
} else if xff := r.Header.Get(xForwardedFor); xff != "" {
i := strings.Index(xff, ", ")
if i == -1 {
i = len(xff)
}
ip = strings.TrimSpace(xff[:i])
}
if len(ip) > 0 {
r.RemoteAddr = ip
}
}
func updateLoginMetrics(user *dataprovider.User, ip string, err error) {
metrics.AddLoginAttempt(dataprovider.LoginMethodPassword)
if err != nil {
logger.ConnectionFailedLog(user.Username, ip, dataprovider.LoginMethodPassword, common.ProtocolWebDAV, err.Error())
event := common.HostEventLoginFailed
if _, ok := err.(*dataprovider.RecordNotFoundError); ok {
event = common.HostEventUserNotFound
}
common.AddDefenderEvent(ip, event)
}
metrics.AddLoginResult(dataprovider.LoginMethodPassword, err)
dataprovider.ExecutePostLoginHook(user, dataprovider.LoginMethodPassword, ip, common.ProtocolWebDAV, err)
}