[FAB-8006] Check for reserved fields in Json

This CR adds a check during simulation for the presence
of reserved fields in the JSON that a chaincode writes via
PutState function.

Change-Id: If91e090fbb835446cb3a081456098e2870965a16
Signed-off-by: manish <manish.sethi@gmail.com>

Author: manish-sethi

core/ledger/kvledger/txmgmt/statedb/statecouchdb/statecouchdb.go

@@ -30,12 +30,15 @@ import (
 
 var logger = flogging.MustGetLogger("statecouchdb")
 
-const binaryWrapper = "valueBytes"
+const (
+	binaryWrapper = "valueBytes"
+	idField       = "_id"
+	revField      = "_rev"
+	versionField  = "~version"
+	deletedField  = "_deleted"
+)
 
-const idField = "_id"
-const revField = "_rev"
-const versionField = "~version"
-const deletedField = "_deleted"
+var reservedFields = []string{idField, revField, versionField, deletedField}
 
 // querySkip is implemented for future use by query paging
 // currently defaulted to 0 and is not used
@@ -234,11 +237,18 @@ func (vdb *VersionedDB) Close() {
 	// no need to close db since a shared couch instance is used
 }
 
-// ValidateKey implements method in VersionedDB interface
-func (vdb *VersionedDB) ValidateKey(key string) error {
+// ValidateKeyValue implements method in VersionedDB interface
+func (vdb *VersionedDB) ValidateKeyValue(key string, value []byte) error {
 	if !utf8.ValidString(key) {
 		return fmt.Errorf("Key should be a valid utf8 string: [%x]", key)
 	}
+	var jsonMap map[string]interface{}
+	err := json.Unmarshal([]byte(value), &jsonMap)
+	if err == nil {
+		// the value is a proper json and hence perform a check that this json does not contain reserved field
+		// if error is not nil then the value will be treated as a binary attachement.
+		return checkReservedFieldsNotUsed(jsonMap)
+	}
 	return nil
 }
 
@@ -992,24 +1002,8 @@ func createCouchdbDocJSON(id, revision string, value []byte, version *version.He
 		}
 	}
 
-	// verify the version field was not included
-	if _, fieldFound := jsonMap[versionField]; fieldFound {
-		return nil, fmt.Errorf("The reserved field %s was found", versionField)
-	}
-
-	// verify the _id field was not included
-	if _, fieldFound := jsonMap[idField]; fieldFound {
-		return nil, fmt.Errorf("The reserved field %s was found", idField)
-	}
-
-	// verify the revision field was not included
-	if _, fieldFound := jsonMap[revField]; fieldFound {
-		return nil, fmt.Errorf("The reserved field %s was found", revField)
-	}
-
-	// verify the deleted field was not included
-	if _, fieldFound := jsonMap[deletedField]; fieldFound {
-		return nil, fmt.Errorf("The reserved field %s was found", deletedField)
+	if err := checkReservedFieldsNotUsed(jsonMap); err != nil {
+		return nil, err
 	}
 
 	// add the version
@@ -1040,6 +1034,16 @@ func createCouchdbDocJSON(id, revision string, value []byte, version *version.He
 
 }
 
+// checkReservedFieldsNotUsed verifies that the reserve field was not included
+func checkReservedFieldsNotUsed(jsonMap map[string]interface{}) error {
+	for _, fieldName := range reservedFields {
+		if _, fieldFound := jsonMap[fieldName]; fieldFound {
+			return fmt.Errorf("The reserved field %s was found", fieldName)
+		}
+	}
+	return nil
+}
+
 // removeJSONRevision removes the "_rev" if this is a JSON
 func removeJSONRevision(jsonValue *[]byte) error {
 

core/ledger/kvledger/txmgmt/statedb/statecouchdb/statecouchdb_test.go

@@ -19,6 +19,7 @@ package statecouchdb
 import (
 	"archive/tar"
 	"bytes"
+	"fmt"
 	"log"
 	"os"
 	"testing"
@@ -196,14 +197,21 @@ func TestUtilityFunctions(t *testing.T) {
 	byteKeySupported := db.BytesKeySuppoted()
 	testutil.AssertEquals(t, byteKeySupported, false)
 
-	// ValidateKey should return nil for a valid key
-	err = db.ValidateKey("testKey")
+	// ValidateKeyValue should return nil for a valid key and value
+	err = db.ValidateKeyValue("testKey", []byte("Some random bytes"))
 	testutil.AssertNil(t, err)
 
 	// ValidateKey should return an error for an invalid key
-	err = db.ValidateKey(string([]byte{0xff, 0xfe, 0xfd}))
+	err = db.ValidateKeyValue(string([]byte{0xff, 0xfe, 0xfd}), []byte("Some random bytes"))
 	testutil.AssertError(t, err, "ValidateKey should have thrown an error for an invalid utf-8 string")
 
+	// ValidateKey should return an error for a json value that already contains one of the reserved fields
+	for _, reservedField := range reservedFields {
+		testVal := fmt.Sprintf(`{"%s":"dummyVal"}`, reservedField)
+		err = db.ValidateKeyValue("testKey", []byte(testVal))
+		testutil.AssertError(t, err, fmt.Sprintf(
+			"ValidateKey should have thrown an error for a json value %s, as contains one of the rserved fields", testVal))
+	}
 }
 
 // TestInvalidJSONFields tests for invalid JSON fields

core/ledger/kvledger/txmgmt/statedb/statedb.go

@@ -42,9 +42,9 @@ type VersionedDB interface {
 	// GetLatestSavePoint returns the height of the highest transaction upto which
 	// the state db is consistent
 	GetLatestSavePoint() (*version.Height, error)
-	// ValidateKey tests whether the key is supported by the db implementation.
+	// ValidateKeyValue tests whether the key and value is supported by the db implementation.
 	// For instance, leveldb supports any bytes for the key while the couchdb supports only valid utf-8 string
-	ValidateKey(key string) error
+	ValidateKeyValue(key string, value []byte) error
 	// BytesKeySuppoted returns true if the implementation (underlying db) supports the any bytes to be used as key.
 	// For instance, leveldb supports any bytes for the key while the couchdb supports only valid utf-8 string
 	BytesKeySuppoted() bool

core/ledger/kvledger/txmgmt/statedb/stateleveldb/stateleveldb.go

@@ -68,8 +68,8 @@ func (vdb *versionedDB) Close() {
 	// do nothing because shared db is used
 }
 
-// ValidateKey implements method in VersionedDB interface
-func (vdb *versionedDB) ValidateKey(key string) error {
+// ValidateKeyValue implements method in VersionedDB interface
+func (vdb *versionedDB) ValidateKeyValue(key string, value []byte) error {
 	return nil
 }
 

core/ledger/kvledger/txmgmt/statedb/stateleveldb/stateleveldb_test.go

@@ -127,7 +127,6 @@ func TestUtilityFunctions(t *testing.T) {
 	byteKeySupported := db.BytesKeySuppoted()
 	testutil.AssertEquals(t, byteKeySupported, true)
 
-	// ValidateKey should return nil for a valid key
-	validKey := db.ValidateKey("testKey")
-	testutil.AssertNil(t, validKey)
+	// ValidateKeyValue should return nil for a valid key and value
+	testutil.AssertNoError(t, db.ValidateKeyValue("testKey", []byte("testValue")), "leveldb should accept all key-values")
 }

core/ledger/kvledger/txmgmt/txmgr/lockbasedtxmgr/lockbased_tx_simulator.go

@@ -54,7 +54,7 @@ func (s *lockBasedTxSimulator) SetState(ns string, key string, value []byte) err
 	if err := s.checkBeforeWrite(); err != nil {
 		return err
 	}
-	if err := s.helper.txmgr.db.ValidateKey(key); err != nil {
+	if err := s.helper.txmgr.db.ValidateKeyValue(key, value); err != nil {
 		return err
 	}
 	s.rwsetBuilder.AddToWriteSet(ns, key, value)
@@ -84,7 +84,7 @@ func (s *lockBasedTxSimulator) SetPrivateData(ns, coll, key string, value []byte
 	if err := s.checkBeforeWrite(); err != nil {
 		return err
 	}
-	if err := s.helper.txmgr.db.ValidateKey(key); err != nil {
+	if err := s.helper.txmgr.db.ValidateKeyValue(key, value); err != nil {
 		return err
 	}
 	s.writePerformed = true