[Feature] Shared cache grants check option

cache/async_cache.go

@@ -20,8 +20,9 @@ type AsyncCache struct {
 
 	graceTime time.Duration
 
-	MaxPayloadSize     config.ByteSize
-	SharedWithAllUsers bool
+	MaxPayloadSize            config.ByteSize
+	SharedWithAllUsers        bool
+	CheckGrantsForSharedCache bool
 }
 
 func (c *AsyncCache) Close() error {
@@ -109,10 +110,11 @@ func NewAsyncCache(cfg config.Cache, maxExecutionTime time.Duration) (*AsyncCach
 	maxPayloadSize := cfg.MaxPayloadSize
 
 	return &AsyncCache{
-		Cache:               cache,
-		TransactionRegistry: transaction,
-		graceTime:           graceTime,
-		MaxPayloadSize:      maxPayloadSize,
-		SharedWithAllUsers:  cfg.SharedWithAllUsers,
+		Cache:                     cache,
+		TransactionRegistry:       transaction,
+		graceTime:                 graceTime,
+		MaxPayloadSize:            maxPayloadSize,
+		SharedWithAllUsers:        cfg.SharedWithAllUsers,
+		CheckGrantsForSharedCache: cfg.CheckGrantsForSharedCache,
 	}, nil
 }

config/README.md

@@ -100,6 +100,10 @@ max_payload_size: <byte_size>
 
 # Whether a query cached by a user can be used by another user
 shared_with_all_users: <bool> | default = false [optional]
+
+# Whether `shared_with_all_users` option is enabled
+# check permissions for cached query used by another user
+check_grants_for_shared_cache: <bool> | default = false [optional]
 ```
 
 ### <distributed_cache_config>

config/config.go

@@ -938,6 +938,10 @@ type Cache struct {
 
 	// Whether a query cached by a user could be used by another user
 	SharedWithAllUsers bool `yaml:"shared_with_all_users,omitempty"`
+
+	// Whether `shared_with_all_users` option is enabled
+	// check permissions for cached query used by another user
+	CheckGrantsForSharedCache bool `yaml:"check_grants_for_shared_cache,omitempty"`
 }
 
 func (c *Cache) setDefaults() {

io.go

@@ -177,3 +177,49 @@ func (crc *cachedReadCloser) String() string {
 	crc.bLock.Unlock()
 	return s
 }
+
+var _ ResponseWriterWithCode = &checkGrantsResponseWriter{}
+
+type checkGrantsResponseWriter struct {
+	http.ResponseWriter
+
+	statusCode int
+}
+
+func (rw *checkGrantsResponseWriter) SetStatusCode(code int) {
+	rw.statusCode = code
+	rw.ResponseWriter.WriteHeader(rw.statusCode)
+}
+
+func (rw *checkGrantsResponseWriter) StatusCode() int {
+	if rw.statusCode == 0 {
+		return http.StatusOK
+	}
+
+	return rw.statusCode
+}
+
+func (rw *checkGrantsResponseWriter) WriteHeader(statusCode int) {
+	// cache statusCode to keep the opportunity to change it in further
+	rw.statusCode = statusCode
+	rw.SetStatusCode(statusCode)
+}
+
+func (rw *checkGrantsResponseWriter) Write(b []byte) (int, error) {
+	if rw.statusCode == http.StatusOK {
+		return 0, nil
+	}
+
+	n, err := rw.ResponseWriter.Write(b)
+	return n, err
+}
+
+// CloseNotify implements http.CloseNotifier
+func (rw *checkGrantsResponseWriter) CloseNotify() <-chan bool {
+	// The rw.ResponseWriter must implement http.CloseNotifier
+	rwc, ok := rw.ResponseWriter.(http.CloseNotifier)
+	if !ok {
+		panic("BUG: the wrapped ResponseWriter must implement http.CloseNotifier")
+	}
+	return rwc.CloseNotify()
+}

proxy.go

@@ -85,7 +85,7 @@
 	}
 }
 
 func (rp *reverseProxy) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 	startTime := time.Now()
 	s, status, err := rp.getScope(req)
 	if err != nil {
@@ -146,6 +146,25 @@
 	}
 
 	if shouldReturnFromCache {
+		// if cache shared between all users
+		// try to check if cached query is allowed for current user
+		if s.user.cache != nil && s.user.cache.SharedWithAllUsers && s.user.cache.CheckGrantsForSharedCache {
+			checkReq, checkQuery, _ := s.createCheckGrantsRequest(req)
+
+			srwCheck := &checkGrantsResponseWriter{
+				ResponseWriter: srw.ResponseWriter,
+			}
+
+			rp.proxyRequest(s, srwCheck, srw, checkReq)
+
+			if srwCheck.statusCode == http.StatusOK {
+				log.Debugf("%s: check grants for shared cached query request success; query: %q; Method: %s; URL: %q", s, checkQuery, checkReq.Method, checkReq.URL.String())
+			} else {
+				log.Debugf("%s: check grants for shared cached query request failure: non-200 status code %d; query: %q; Method: %s; URL: %q", s, srwCheck.statusCode, checkQuery, checkReq.Method, checkReq.URL.String())
+				return
+			}
+		}
+
 		rp.serveFromCache(s, srw, req, origParams, q)
 	} else {
 		rp.proxyRequest(s, srw, srw, req)
@@ -925,3 +944,40 @@
 	s.requestPacketSize = len(q)
 	return s, 0, nil
 }
+
+// create a new request based on proxied one
+// with query wrapped to fetch result types like:
+// 'DESC ({original_query})'
+// along with query parsed and analyzed for return types (which is fast)
+// ClickHouse check permissions to execute this query for the user
+func (s *scope) createCheckGrantsRequest(originalReq *http.Request) (*http.Request, string, error) {
+	originalQuery := originalReq.URL.Query().Get("query")
+	checkQuery := fmt.Sprintf("DESC (%s);", strings.TrimRight(originalQuery, ";"))
+
+	newURL := *originalReq.URL
+
+	queryParams, err := url.ParseQuery(newURL.RawQuery)
+	if err != nil {
+		return nil, checkQuery, err
+	}
+
+	queryParams.Set("query", checkQuery)
+
+	newURL.RawQuery = queryParams.Encode()
+
+	req := &http.Request{
+		Method:        originalReq.Method,
+		URL:           &newURL,
+		Proto:         originalReq.Proto,
+		ProtoMajor:    originalReq.ProtoMajor,
+		ProtoMinor:    originalReq.ProtoMinor,
+		Header:        originalReq.Header.Clone(),
+		Body:          originalReq.Body,
+		Host:          originalReq.Host,
+		ContentLength: originalReq.ContentLength,
+		Close:         originalReq.Close,
+		TLS:           originalReq.TLS,
+	}
+
+	return req, checkQuery, nil
+}