go_study/fabric-main/common/deliver/binding.go

68 lines
2.2 KiB
Go

/*
Copyright IBM Corp. All Rights Reserved.
SPDX-License-Identifier: Apache-2.0
*/
package deliver
import (
"bytes"
"context"
"github.com/golang/protobuf/proto"
"github.com/hyperledger/fabric/common/util"
"github.com/pkg/errors"
)
// BindingInspector receives as parameters a gRPC context and an Envelope,
// and verifies whether the message contains an appropriate binding to the context
type BindingInspector func(context.Context, proto.Message) error
// CertHashExtractor extracts a certificate from a proto.Message message
type CertHashExtractor func(proto.Message) []byte
// NewBindingInspector returns a BindingInspector according to whether
// mutualTLS is configured or not, and according to a function that extracts
// TLS certificate hashes from proto messages
func NewBindingInspector(mutualTLS bool, extractTLSCertHash CertHashExtractor) BindingInspector {
if extractTLSCertHash == nil {
panic(errors.New("extractTLSCertHash parameter is nil"))
}
inspectMessage := mutualTLSBinding
if !mutualTLS {
inspectMessage = noopBinding
}
return func(ctx context.Context, msg proto.Message) error {
if msg == nil {
return errors.New("message is nil")
}
return inspectMessage(ctx, extractTLSCertHash(msg))
}
}
// mutualTLSBinding enforces the client to send its TLS cert hash in the message,
// and then compares it to the computed hash that is derived
// from the gRPC context.
// In case they don't match, or the cert hash is missing from the request or
// there is no TLS certificate to be excavated from the gRPC context,
// an error is returned.
func mutualTLSBinding(ctx context.Context, claimedTLScertHash []byte) error {
if len(claimedTLScertHash) == 0 {
return errors.Errorf("client didn't include its TLS cert hash")
}
actualTLScertHash := util.ExtractCertificateHashFromContext(ctx)
if len(actualTLScertHash) == 0 {
return errors.Errorf("client didn't send a TLS certificate")
}
if !bytes.Equal(actualTLScertHash, claimedTLScertHash) {
return errors.Errorf("claimed TLS cert hash is %v but actual TLS cert hash is %v", claimedTLScertHash, actualTLScertHash)
}
return nil
}
// noopBinding is a BindingInspector that always returns nil
func noopBinding(_ context.Context, _ []byte) error {
return nil
}