Set the maximum size increase the copy operations in a json patch can cause

cmd/kube-apiserver/app/options/options_test.go

@@ -129,6 +129,7 @@ func TestAddFlags(t *testing.T) {
 			MaxMutatingRequestsInFlight: 200,
 			RequestTimeout:              time.Duration(2) * time.Minute,
 			MinRequestTimeout:           1800,
+			JSONPatchMaxCopyBytes:       int64(10 * 1024 * 1024),
 		},
 		Admission: &kubeoptions.AdmissionOptions{
 			GenericAdmission: &apiserveroptions.AdmissionOptions{

staging/src/k8s.io/apiserver/pkg/server/BUILD

@@ -108,6 +108,7 @@ go_library(
         "//staging/src/k8s.io/component-base/logs:go_default_library",
         "//vendor/github.com/coreos/go-systemd/daemon:go_default_library",
         "//vendor/github.com/emicklei/go-restful:go_default_library",
+        "//vendor/github.com/evanphx/json-patch:go_default_library",
         "//vendor/github.com/go-openapi/spec:go_default_library",
         "//vendor/github.com/pborman/uuid:go_default_library",
         "//vendor/golang.org/x/net/http2:go_default_library",

staging/src/k8s.io/apiserver/pkg/server/config.go

@@ -26,8 +26,10 @@ import (
 	"sort"
 	"strconv"
 	"strings"
+	"sync/atomic"
 	"time"
 
+	jsonpatch "github.com/evanphx/json-patch"
 	"github.com/go-openapi/spec"
 	"github.com/pborman/uuid"
 	"k8s.io/klog"
@@ -153,6 +155,10 @@ type Config struct {
 	// If specified, long running requests such as watch will be allocated a random timeout between this value, and
 	// twice this value.  Note that it is up to the request handlers to ignore or honor this timeout. In seconds.
 	MinRequestTimeout int
+	// The limit on the total size increase all "copy" operations in a json
+	// patch may cause.
+	// This affects all places that applies json patch in the binary.
+	JSONPatchMaxCopyBytes int64
 	// MaxRequestsInFlight is the maximum number of parallel non-long-running requests. Every further
 	// request has to wait. Applies only to non-mutating requests.
 	MaxRequestsInFlight int
@@ -257,6 +263,12 @@ func NewConfig(codecs serializer.CodecFactory) *Config {
 		MaxMutatingRequestsInFlight: 200,
 		RequestTimeout:              time.Duration(60) * time.Second,
 		MinRequestTimeout:           1800,
+		// 10MB is the recommended maximum client request size in bytes
+		// the etcd server should accept. Thus, we set it as the limit
+		// on the size increase the "copy" operations in a json patch
+		// can cause.  See
+		// https://github.com/etcd-io/etcd/blob/release-3.3/etcdserver/server.go#L90.
+		JSONPatchMaxCopyBytes:        int64(10 * 1024 * 1024),
 		EnableAPIResponseCompression: utilfeature.DefaultFeatureGate.Enabled(features.APIResponseCompression),
 
 		// Default to treating watch as a long-running operation
@@ -451,6 +463,19 @@ func (c completedConfig) New(name string, delegationTarget DelegationTarget) (*G
 		enableAPIResponseCompression: c.EnableAPIResponseCompression,
 	}
 
+	for {
+		if c.JSONPatchMaxCopyBytes <= 0 {
+			break
+		}
+		existing := atomic.LoadInt64(&jsonpatch.AccumulatedCopySizeLimit)
+		if existing > 0 && existing < c.JSONPatchMaxCopyBytes {
+			break
+		}
+		if atomic.CompareAndSwapInt64(&jsonpatch.AccumulatedCopySizeLimit, existing, c.JSONPatchMaxCopyBytes) {
+			break
+		}
+	}
+
 	for k, v := range delegationTarget.PostStartHooks() {
 		s.postStartHooks[k] = v
 	}

staging/src/k8s.io/apiserver/pkg/server/options/server_run_options.go

@@ -42,6 +42,9 @@ type ServerRunOptions struct {
 	MaxMutatingRequestsInFlight int
 	RequestTimeout              time.Duration
 	MinRequestTimeout           int
+	// We intentionally did not add a flag for this option. Users of the
+	// apiserver library can wire it to a flag.
+	JSONPatchMaxCopyBytes int64
 	TargetRAMMB           int
 }
 
@@ -52,6 +55,7 @@ func NewServerRunOptions() *ServerRunOptions {
 		MaxMutatingRequestsInFlight: defaults.MaxMutatingRequestsInFlight,
 		RequestTimeout:              defaults.RequestTimeout,
 		MinRequestTimeout:           defaults.MinRequestTimeout,
+		JSONPatchMaxCopyBytes:       defaults.JSONPatchMaxCopyBytes,
 	}
 }
 
@@ -63,6 +67,7 @@ func (s *ServerRunOptions) ApplyTo(c *server.Config) error {
 	c.MaxMutatingRequestsInFlight = s.MaxMutatingRequestsInFlight
 	c.RequestTimeout = s.RequestTimeout
 	c.MinRequestTimeout = s.MinRequestTimeout
+	c.JSONPatchMaxCopyBytes = s.JSONPatchMaxCopyBytes
 	c.PublicAddress = s.AdvertiseAddress
 
 	return nil
@@ -107,10 +112,14 @@ func (s *ServerRunOptions) Validate() []error {
 		errors = append(errors, fmt.Errorf("--min-request-timeout can not be negative value"))
 	}
 
+	if s.JSONPatchMaxCopyBytes < 0 {
+		errors = append(errors, fmt.Errorf("--json-patch-max-copy-bytes can not be negative value"))
+	}
+
 	return errors
 }
 
-// AddFlags adds flags for a specific APIServer to the specified FlagSet
+// AddUniversalFlags adds flags for a specific APIServer to the specified FlagSet
 func (s *ServerRunOptions) AddUniversalFlags(fs *pflag.FlagSet) {
 	// Note: the weird ""+ in below lines seems to be the only way to get gofmt to
 	// arrange these text blocks sensibly. Grrr.

staging/src/k8s.io/apiserver/pkg/server/options/server_run_options_test.go

@@ -40,6 +40,7 @@ func TestServerRunOptionsValidate(t *testing.T) {
 				MaxMutatingRequestsInFlight: 200,
 				RequestTimeout:              time.Duration(2) * time.Minute,
 				MinRequestTimeout:           1800,
+				JSONPatchMaxCopyBytes:       10 * 1024 * 1024,
 				TargetRAMMB:                 -65536,
 			},
 			expectErr: "--target-ram-mb can not be negative value",
@@ -53,6 +54,7 @@ func TestServerRunOptionsValidate(t *testing.T) {
 				MaxMutatingRequestsInFlight: 200,
 				RequestTimeout:              time.Duration(2) * time.Minute,
 				MinRequestTimeout:           1800,
+				JSONPatchMaxCopyBytes:       10 * 1024 * 1024,
 				TargetRAMMB:                 65536,
 			},
 			expectErr: "--max-requests-inflight can not be negative value",
@@ -66,6 +68,7 @@ func TestServerRunOptionsValidate(t *testing.T) {
 				MaxMutatingRequestsInFlight: -200,
 				RequestTimeout:              time.Duration(2) * time.Minute,
 				MinRequestTimeout:           1800,
+				JSONPatchMaxCopyBytes:       10 * 1024 * 1024,
 				TargetRAMMB:                 65536,
 			},
 			expectErr: "--max-mutating-requests-inflight can not be negative value",
@@ -79,6 +82,7 @@ func TestServerRunOptionsValidate(t *testing.T) {
 				MaxMutatingRequestsInFlight: 200,
 				RequestTimeout:              -time.Duration(2) * time.Minute,
 				MinRequestTimeout:           1800,
+				JSONPatchMaxCopyBytes:       10 * 1024 * 1024,
 				TargetRAMMB:                 65536,
 			},
 			expectErr: "--request-timeout can not be negative value",
@@ -92,10 +96,25 @@ func TestServerRunOptionsValidate(t *testing.T) {
 				MaxMutatingRequestsInFlight: 200,
 				RequestTimeout:              time.Duration(2) * time.Minute,
 				MinRequestTimeout:           -1800,
+				JSONPatchMaxCopyBytes:       10 * 1024 * 1024,
 				TargetRAMMB:                 65536,
 			},
 			expectErr: "--min-request-timeout can not be negative value",
 		},
+		{
+			name: "Test when JSONPatchMaxCopyBytes is negative value",
+			testOptions: &ServerRunOptions{
+				AdvertiseAddress:            net.ParseIP("192.168.10.10"),
+				CorsAllowedOriginList:       []string{"10.10.10.100", "10.10.10.200"},
+				MaxRequestsInFlight:         400,
+				MaxMutatingRequestsInFlight: 200,
+				RequestTimeout:              time.Duration(2) * time.Minute,
+				MinRequestTimeout:           1800,
+				JSONPatchMaxCopyBytes:       -10 * 1024 * 1024,
+				TargetRAMMB:                 65536,
+			},
+			expectErr: "--json-patch-max-copy-bytes can not be negative value",
+		},
 		{
 			name: "Test when ServerRunOptions is valid",
 			testOptions: &ServerRunOptions{
@@ -105,6 +124,7 @@ func TestServerRunOptionsValidate(t *testing.T) {
 				MaxMutatingRequestsInFlight: 200,
 				RequestTimeout:              time.Duration(2) * time.Minute,
 				MinRequestTimeout:           1800,
+				JSONPatchMaxCopyBytes:       10 * 1024 * 1024,
 				TargetRAMMB:                 65536,
 			},
 		},