github.com/leonlxy/hyperledger@v1.0.0-alpha.0.20170427033203-34922035d248/common/cauthdsl/policy.go (about)

     1  /*
     2  Copyright IBM Corp. 2016 All Rights Reserved.
     3  
     4  Licensed under the Apache License, Version 2.0 (the "License");
     5  you may not use this file except in compliance with the License.
     6  You may obtain a copy of the License at
     7  
     8                   http://www.apache.org/licenses/LICENSE-2.0
     9  
    10  Unless required by applicable law or agreed to in writing, software
    11  distributed under the License is distributed on an "AS IS" BASIS,
    12  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    13  See the License for the specific language governing permissions and
    14  limitations under the License.
    15  */
    16  
    17  package cauthdsl
    18  
    19  import (
    20  	"errors"
    21  	"fmt"
    22  
    23  	"github.com/hyperledger/fabric/common/policies"
    24  	cb "github.com/hyperledger/fabric/protos/common"
    25  
    26  	"github.com/golang/protobuf/proto"
    27  	"github.com/hyperledger/fabric/msp"
    28  )
    29  
    30  type provider struct {
    31  	deserializer msp.IdentityDeserializer
    32  }
    33  
    34  // NewProviderImpl provides a policy generator for cauthdsl type policies
    35  func NewPolicyProvider(deserializer msp.IdentityDeserializer) policies.Provider {
    36  	return &provider{
    37  		deserializer: deserializer,
    38  	}
    39  }
    40  
    41  // NewPolicy creates a new policy based on the policy bytes
    42  func (pr *provider) NewPolicy(data []byte) (policies.Policy, proto.Message, error) {
    43  	sigPolicy := &cb.SignaturePolicyEnvelope{}
    44  	if err := proto.Unmarshal(data, sigPolicy); err != nil {
    45  		return nil, nil, fmt.Errorf("Error unmarshaling to SignaturePolicy: %s", err)
    46  	}
    47  
    48  	if sigPolicy.Version != 0 {
    49  		return nil, nil, fmt.Errorf("This evaluator only understands messages of version 0, but version was %d", sigPolicy.Version)
    50  	}
    51  
    52  	compiled, err := compile(sigPolicy.Policy, sigPolicy.Identities, pr.deserializer)
    53  	if err != nil {
    54  		return nil, nil, err
    55  	}
    56  
    57  	return &policy{
    58  		evaluator: compiled,
    59  	}, sigPolicy, nil
    60  
    61  }
    62  
    63  type policy struct {
    64  	evaluator func([]*cb.SignedData, []bool) bool
    65  }
    66  
    67  // Evaluate takes a set of SignedData and evaluates whether this set of signatures satisfies the policy
    68  func (p *policy) Evaluate(signatureSet []*cb.SignedData) error {
    69  	if p == nil {
    70  		return fmt.Errorf("No such policy")
    71  	}
    72  
    73  	ok := p.evaluator(signatureSet, make([]bool, len(signatureSet)))
    74  	if !ok {
    75  		return errors.New("Failed to authenticate policy")
    76  	}
    77  	return nil
    78  }