[FAB-1697] Add chain hashing algorithm config

https://jira.hyperledger.org/browse/FAB-1697

This changeset adds the chain hashing algorithm to the configuration
proto.  It also adds a chain configuration consumer (for configuration
items of chain type) which is capable of processing this message once
embedded in the genesis block.

Actually embedding this and utilizing the chain configuration will come
in later changesets.

Change-Id: I960ce4c6ca73b988840585364876e970cbf99a47
Signed-off-by: Jason Yellick <jyellick@us.ibm.com>

Author: Jason Yellick

common/chainconfig/chainconfig.go

@@ -0,0 +1,120 @@
+/*
+Copyright IBM Corp. 2017 All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+                 http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package chainconfig
+
+import (
+	"fmt"
+
+	"github.com/hyperledger/fabric/common/util"
+	cb "github.com/hyperledger/fabric/protos/common"
+
+	"github.com/golang/protobuf/proto"
+	"github.com/op/go-logging"
+)
+
+// Chain config keys
+const (
+	// HashingAlgorithmKey is the cb.ConfigurationItem type key name for the HashingAlgorithm message
+	HashingAlgorithmKey = "HashingAlgorithm"
+)
+
+// Hashing algorithm types
+const (
+	// SHAKE256 is the algorithm type for the sha3 shake256 hashing algorithm with 512 bits of output
+	SHA3Shake256 = "SHAKE256"
+)
+
+var logger = logging.MustGetLogger("common/chainconfig")
+
+// Descriptor stores the common chain configuration
+// It is intended to be the primary accessor of DescriptorImpl
+// It is intended to discourage use of the other exported DescriptorImpl methods
+// which are used for updating the chain configuration by the configtx.Manager
+type Descriptor interface {
+	// HashingAlgorithm returns the default algorithm to be used when hashing
+	// such as computing block hashes, and CreationPolicy digests
+	HashingAlgorithm() func(input []byte) []byte
+}
+
+type chainConfig struct {
+	hashingAlgorithm func(input []byte) []byte
+}
+
+// DescriptorImpl is an implementation of Manager and configtx.ConfigHandler
+// In general, it should only be referenced as an Impl for the configtx.Manager
+type DescriptorImpl struct {
+	pendingConfig *chainConfig
+	config        *chainConfig
+}
+
+// NewDescriptorImpl creates a new DescriptorImpl with the given CryptoHelper
+func NewDescriptorImpl() *DescriptorImpl {
+	return &DescriptorImpl{
+		config: &chainConfig{},
+	}
+}
+
+// HashingAlgorithm returns a function pointer to the chain hashing algorihtm
+func (pm *DescriptorImpl) HashingAlgorithm() func(input []byte) []byte {
+	return pm.config.hashingAlgorithm
+}
+
+// BeginConfig is used to start a new configuration proposal
+func (pm *DescriptorImpl) BeginConfig() {
+	if pm.pendingConfig != nil {
+		logger.Panicf("Programming error, cannot call begin in the middle of a proposal")
+	}
+	pm.pendingConfig = &chainConfig{}
+}
+
+// RollbackConfig is used to abandon a new configuration proposal
+func (pm *DescriptorImpl) RollbackConfig() {
+	pm.pendingConfig = nil
+}
+
+// CommitConfig is used to commit a new configuration proposal
+func (pm *DescriptorImpl) CommitConfig() {
+	if pm.pendingConfig == nil {
+		logger.Panicf("Programming error, cannot call commit without an existing proposal")
+	}
+	pm.config = pm.pendingConfig
+	pm.pendingConfig = nil
+}
+
+// ProposeConfig is used to add new configuration to the configuration proposal
+func (pm *DescriptorImpl) ProposeConfig(configItem *cb.ConfigurationItem) error {
+	if configItem.Type != cb.ConfigurationItem_Chain {
+		return fmt.Errorf("Expected type of ConfigurationItem_Chain, got %v", configItem.Type)
+	}
+
+	switch configItem.Key {
+	case HashingAlgorithmKey:
+		hashingAlgorithm := &cb.HashingAlgorithm{}
+		if err := proto.Unmarshal(configItem.Value, hashingAlgorithm); err != nil {
+			return fmt.Errorf("Unmarshaling error for HashingAlgorithm: %s", err)
+		}
+		switch hashingAlgorithm.Name {
+		case SHA3Shake256:
+			pm.pendingConfig.hashingAlgorithm = util.ComputeCryptoHash
+		default:
+			return fmt.Errorf("Unknown hashing algorithm type: %s", hashingAlgorithm.Name)
+		}
+	default:
+		logger.Warningf("Uknown Chain configuration item with key %s", configItem.Key)
+	}
+	return nil
+}

common/chainconfig/chainconfig_test.go

@@ -0,0 +1,104 @@
+/*
+Copyright IBM Corp. 2017 All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+                 http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package chainconfig
+
+import (
+	"testing"
+
+	cb "github.com/hyperledger/fabric/protos/common"
+	"github.com/hyperledger/fabric/protos/utils"
+
+	logging "github.com/op/go-logging"
+)
+
+func init() {
+	logging.SetLevel(logging.DEBUG, "")
+}
+
+func TestDoubleBegin(t *testing.T) {
+	defer func() {
+		if err := recover(); err == nil {
+			t.Fatalf("Should have panicked on multiple begin configs")
+		}
+	}()
+
+	m := NewDescriptorImpl()
+	m.BeginConfig()
+	m.BeginConfig()
+}
+
+func TestCommitWithoutBegin(t *testing.T) {
+	defer func() {
+		if err := recover(); err == nil {
+			t.Fatalf("Should have panicked on multiple begin configs")
+		}
+	}()
+
+	m := NewDescriptorImpl()
+	m.CommitConfig()
+}
+
+func TestRollback(t *testing.T) {
+	m := NewDescriptorImpl()
+	m.pendingConfig = &chainConfig{}
+	m.RollbackConfig()
+	if m.pendingConfig != nil {
+		t.Fatalf("Should have cleared pending config on rollback")
+	}
+}
+
+func TestHashingAlgorithm(t *testing.T) {
+	invalidMessage :=
+		&cb.ConfigurationItem{
+			Type:  cb.ConfigurationItem_Chain,
+			Key:   HashingAlgorithmKey,
+			Value: []byte("Garbage Data"),
+		}
+	invalidAlgorithm := &cb.ConfigurationItem{
+		Type:  cb.ConfigurationItem_Chain,
+		Key:   HashingAlgorithmKey,
+		Value: utils.MarshalOrPanic(&cb.HashingAlgorithm{Name: "MD5"}),
+	}
+	validAlgorithm := &cb.ConfigurationItem{
+		Type:  cb.ConfigurationItem_Chain,
+		Key:   HashingAlgorithmKey,
+		Value: utils.MarshalOrPanic(&cb.HashingAlgorithm{Name: SHA3Shake256}),
+	}
+	m := NewDescriptorImpl()
+	m.BeginConfig()
+
+	err := m.ProposeConfig(invalidMessage)
+	if err == nil {
+		t.Fatalf("Should have failed on invalid message")
+	}
+
+	err = m.ProposeConfig(invalidAlgorithm)
+	if err == nil {
+		t.Fatalf("Should have failed on invalid algorithm")
+	}
+
+	err = m.ProposeConfig(validAlgorithm)
+	if err != nil {
+		t.Fatalf("Error applying valid config: %s", err)
+	}
+
+	m.CommitConfig()
+
+	if m.HashingAlgorithm() == nil {
+		t.Fatalf("Should have set default hashing algorithm")
+	}
+}

protos/common/common.pb.go

@@ -116,3 +116,11 @@ message SignaturePolicy {
         NOutOf From = 2;
     }
 }
+
+
+// HashingAlgorithm is encoded into the configuration transaction as  a configuration item of type CHAIN
+// with a Key of "HashingAlgorithm" as marshaled protobuf bytes
+message HashingAlgorithm {
+    // Currently supported algorithms are: SHAKE256
+    string name = 1;
+}