package handler import ( "encoding/xml" "fmt" "net/http" "strconv" "strings" "github.com/nspcc-dev/neofs-s3-gw/api" "github.com/nspcc-dev/neofs-s3-gw/api/errors" "github.com/nspcc-dev/neofs-s3-gw/api/layer" ) type ( // CORSConfiguration stores CORS configuration of a request. CORSConfiguration struct { XMLName xml.Name `xml:"http://s3.amazonaws.com/doc/2006-03-01/ CORSConfiguration" json:"-"` CORSRules []CORSRule `xml:"CORSRule" json:"CORSRules"` } // CORSRule stores rules for CORS in a bucket. CORSRule struct { ID string `xml:"ID,omitempty" json:"ID,omitempty"` AllowedHeaders []string `xml:"AllowedHeader" json:"AllowedHeaders"` AllowedMethods []string `xml:"AllowedMethod" json:"AllowedMethods"` AllowedOrigins []string `xml:"AllowedOrigin" json:"AllowedOrigins"` ExposeHeaders []string `xml:"ExposeHeader" json:"ExposeHeaders"` MaxAgeSeconds int `xml:"MaxAgeSeconds,omitempty" json:"MaxAgeSeconds,omitempty"` } ) const ( // DefaultMaxAge -- default value of Access-Control-Max-Age if this value is not set in a rule. DefaultMaxAge = 600 wildcard = "*" ) var supportedMethods = map[string]struct{}{"GET": {}, "HEAD": {}, "POST": {}, "PUT": {}, "DELETE": {}} func (h *handler) GetBucketCorsHandler(w http.ResponseWriter, r *http.Request) { reqInfo := api.GetReqInfo(r.Context()) bktInfo, err := h.obj.GetBucketInfo(r.Context(), reqInfo.BucketName) if err != nil { h.logAndSendError(w, "could not get bucket info", reqInfo, err) return } if err = checkOwner(bktInfo, r.Header.Get(api.AmzExpectedBucketOwner)); err != nil { h.logAndSendError(w, "expected owner doesn't match", reqInfo, err) return } info, err := h.obj.GetBucketCORS(r.Context(), bktInfo) if err != nil { h.logAndSendError(w, "could not get cors", reqInfo, err) return } api.WriteResponse(w, http.StatusOK, info, api.MimeNone) } func (h *handler) PutBucketCorsHandler(w http.ResponseWriter, r *http.Request) { reqInfo := api.GetReqInfo(r.Context()) bktInfo, err := h.obj.GetBucketInfo(r.Context(), reqInfo.BucketName) if err != nil { h.logAndSendError(w, "could not get bucket info", reqInfo, err) return } if err = checkOwner(bktInfo, r.Header.Get(api.AmzExpectedBucketOwner)); err != nil { h.logAndSendError(w, "expected owner doesn't match", reqInfo, err) return } cors := &CORSConfiguration{} if err := xml.NewDecoder(r.Body).Decode(cors); err != nil { h.logAndSendError(w, "could not parse cors configuration", reqInfo, err) return } if cors.CORSRules == nil { h.logAndSendError(w, "could not parse cors rules", reqInfo, errors.GetAPIError(errors.ErrMalformedXML)) return } if err = checkCORS(cors); err != nil { h.logAndSendError(w, "invalid cors configuration", reqInfo, err) return } xml, err := xml.Marshal(cors) if err != nil { h.logAndSendError(w, "could not encode cors configuration to xml", reqInfo, err) return } p := &layer.PutCORSParams{ BktInfo: bktInfo, CORSConfiguration: xml, } if err = h.obj.PutBucketCORS(r.Context(), p); err != nil { h.logAndSendError(w, "could not put cors configuration", reqInfo, err) return } api.WriteSuccessResponseHeadersOnly(w) } func (h *handler) DeleteBucketCorsHandler(w http.ResponseWriter, r *http.Request) { reqInfo := api.GetReqInfo(r.Context()) bktInfo, err := h.obj.GetBucketInfo(r.Context(), reqInfo.BucketName) if err != nil { h.logAndSendError(w, "could not get bucket info", reqInfo, err) return } if err = checkOwner(bktInfo, r.Header.Get(api.AmzExpectedBucketOwner)); err != nil { h.logAndSendError(w, "expected owner doesn't match", reqInfo, err) return } if err := h.obj.DeleteBucketCORS(r.Context(), bktInfo); err != nil { h.logAndSendError(w, "could not delete cors", reqInfo, err) } w.WriteHeader(http.StatusNoContent) } func (h *handler) AppendCORSHeaders(w http.ResponseWriter, r *http.Request) { if r.Method == http.MethodOptions { return } origin := r.Header.Get(api.Origin) if origin == "" { return } reqInfo := api.GetReqInfo(r.Context()) if reqInfo.BucketName == "" { return } bktInfo, err := h.obj.GetBucketInfo(r.Context(), reqInfo.BucketName) if err != nil { return } info, err := h.obj.GetBucketCORS(r.Context(), bktInfo) if err != nil { return } cors := &CORSConfiguration{} if err = xml.Unmarshal(info, cors); err != nil { return } withCredentials := r.Header.Get(api.Authorization) != "" for _, rule := range cors.CORSRules { for _, o := range rule.AllowedOrigins { if o == origin { for _, m := range rule.AllowedMethods { if m == r.Method { w.Header().Set(api.AccessControlAllowOrigin, origin) w.Header().Set(api.AccessControlAllowCredentials, "true") w.Header().Set(api.Vary, api.Origin) return } } } if o == wildcard { for _, m := range rule.AllowedMethods { if m == r.Method { if withCredentials { w.Header().Set(api.AccessControlAllowOrigin, origin) w.Header().Set(api.AccessControlAllowCredentials, "true") w.Header().Set(api.Vary, api.Origin) } else { w.Header().Set(api.AccessControlAllowOrigin, o) } return } } } } } } func (h *handler) Preflight(w http.ResponseWriter, r *http.Request) { reqInfo := api.GetReqInfo(r.Context()) bktInfo, err := h.obj.GetBucketInfo(r.Context(), reqInfo.BucketName) if err != nil { h.logAndSendError(w, "could not get bucket info", reqInfo, err) return } origin := r.Header.Get(api.Origin) if origin == "" { h.logAndSendError(w, "origin request header needed", reqInfo, errors.GetAPIError(errors.ErrBadRequest)) } method := r.Header.Get(api.AccessControlRequestMethod) if method == "" { h.logAndSendError(w, "Access-Control-Request-Method request header needed", reqInfo, errors.GetAPIError(errors.ErrBadRequest)) return } var headers []string requestHeaders := r.Header.Get(api.AccessControlRequestHeaders) if requestHeaders != "" { headers = strings.Split(requestHeaders, ", ") } info, err := h.obj.GetBucketCORS(r.Context(), bktInfo) if err != nil { h.logAndSendError(w, "could not get cors", reqInfo, err) return } cors := &CORSConfiguration{} if err = xml.Unmarshal(info, cors); err != nil { h.logAndSendError(w, "could not parse cors configuration", reqInfo, err) return } for _, rule := range cors.CORSRules { for _, o := range rule.AllowedOrigins { if o == origin || o == wildcard { for _, m := range rule.AllowedMethods { if m == method { if !checkSubslice(rule.AllowedHeaders, headers) { continue } w.Header().Set(api.AccessControlAllowOrigin, o) w.Header().Set(api.AccessControlAllowMethods, strings.Join(rule.AllowedMethods, ", ")) if headers != nil { w.Header().Set(api.AccessControlAllowHeaders, requestHeaders) } if rule.ExposeHeaders != nil { w.Header().Set(api.AccessControlExposeHeaders, strings.Join(rule.ExposeHeaders, ", ")) } if rule.MaxAgeSeconds > 0 || rule.MaxAgeSeconds == -1 { w.Header().Set(api.AccessControlMaxAge, strconv.Itoa(rule.MaxAgeSeconds)) } else { w.Header().Set(api.AccessControlMaxAge, strconv.Itoa(h.cfg.DefaultMaxAge)) } if o != wildcard { w.Header().Set(api.AccessControlAllowCredentials, "true") } api.WriteSuccessResponseHeadersOnly(w) return } } } } } h.logAndSendError(w, "Forbidden", reqInfo, errors.GetAPIError(errors.ErrAccessDenied)) } func checkCORS(cors *CORSConfiguration) error { for _, r := range cors.CORSRules { for _, m := range r.AllowedMethods { if _, ok := supportedMethods[m]; !ok { return fmt.Errorf("unsupported HTTP method in CORS config %s", m) } } for _, h := range r.ExposeHeaders { if h == wildcard { return fmt.Errorf("ExposeHeader \"*\" contains wildcard. We currently do not support wildcard " + "for ExposeHeader") } } } return nil } func checkSubslice(slice []string, subSlice []string) bool { if sliceContains(slice, wildcard) { return true } if len(subSlice) > len(slice) { return false } for _, r := range subSlice { if !sliceContains(slice, r) { return false } } return true } func sliceContains(slice []string, str string) bool { for _, s := range slice { if s == str { return true } } return false }