mirror of https://github.com/perkeep/perkeep.git
143 lines
4.1 KiB
Go
143 lines
4.1 KiB
Go
/*
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Copyright 2013 The Perkeep Authors
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package schema
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import (
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"context"
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"errors"
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"fmt"
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"io"
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"io/ioutil"
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"os"
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"strings"
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"time"
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"perkeep.org/pkg/blob"
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"perkeep.org/pkg/jsonsign"
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"golang.org/x/crypto/openpgp"
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)
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// A Signer signs the JSON schema blobs that require signing, such as claims
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// and permanodes.
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type Signer struct {
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keyID string // short one; 8 capital hex digits
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pubref blob.Ref
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privEntity *openpgp.Entity
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// baseSigReq is the prototype signing request used with the jsonsig
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// package.
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baseSigReq jsonsign.SignRequest
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}
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func (s *Signer) String() string {
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return fmt.Sprintf("[*schema.Signer for key=%s pubkey=%s]", s.keyID, s.pubref)
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}
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// KeyID returns the short (8 digit) capital hex GPG key ID.
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func (s *Signer) KeyID() string {
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return s.keyID
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}
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// KeyIDLong returns the long (16 digit) capital hex GPG key ID.
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func (s *Signer) KeyIDLong() string {
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return s.privEntity.PrivateKey.KeyIdString()
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}
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// Entity returns the signer's entity, which includes its public and private keys.
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func (s *Signer) Entity() *openpgp.Entity {
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return s.privEntity
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}
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// NewSigner returns an Signer given an armored public key's blobref,
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// its armored content, and its associated private key entity.
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// The privateKeySource must be either an *openpgp.Entity or a string filename to a secret key.
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func NewSigner(pubKeyRef blob.Ref, armoredPubKey io.Reader, privateKeySource interface{}) (*Signer, error) {
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hash := pubKeyRef.Hash()
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keyID, armoredPubKeyString, err := jsonsign.ParseArmoredPublicKey(io.TeeReader(armoredPubKey, hash))
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if err != nil {
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return nil, err
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}
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if !pubKeyRef.HashMatches(hash) {
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return nil, fmt.Errorf("pubkey ref of %v doesn't match provided armored public key", pubKeyRef)
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}
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var privateKey *openpgp.Entity
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switch v := privateKeySource.(type) {
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case *openpgp.Entity:
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privateKey = v
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case string:
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privateKey, err = jsonsign.EntityFromSecring(keyID, v)
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if err != nil {
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return nil, err
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}
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default:
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return nil, fmt.Errorf("invalid privateKeySource type %T", v)
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}
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if privateKey == nil {
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return nil, errors.New("nil privateKey")
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}
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return &Signer{
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keyID: keyID,
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pubref: pubKeyRef,
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privEntity: privateKey,
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baseSigReq: jsonsign.SignRequest{
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ServerMode: true, // shouldn't matter, since we're supplying the rest of the fields
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Fetcher: memoryBlobFetcher{
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pubKeyRef: func() (uint32, io.ReadCloser) {
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return uint32(len(armoredPubKeyString)), ioutil.NopCloser(strings.NewReader(armoredPubKeyString))
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},
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},
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EntityFetcher: entityFetcherFunc(func(wantKeyId string) (*openpgp.Entity, error) {
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if privateKey.PrivateKey.KeyIdString() != wantKeyId &&
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privateKey.PrivateKey.KeyIdShortString() != wantKeyId {
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return nil, fmt.Errorf("jsonsign code unexpectedly requested keyID %q; only have %q",
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wantKeyId, keyID)
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}
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return privateKey, nil
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}),
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},
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}, nil
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}
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// SignJSON signs the provided json at the optional time t.
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// If t is the zero Time, the current time is used.
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func (s *Signer) SignJSON(ctx context.Context, json string, t time.Time) (string, error) {
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sr := s.baseSigReq
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sr.UnsignedJSON = json
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sr.SignatureTime = t
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return sr.Sign(ctx)
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}
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type memoryBlobFetcher map[blob.Ref]func() (size uint32, rc io.ReadCloser)
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func (m memoryBlobFetcher) Fetch(ctx context.Context, br blob.Ref) (file io.ReadCloser, size uint32, err error) {
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fn, ok := m[br]
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if !ok {
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return nil, 0, os.ErrNotExist
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}
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size, file = fn()
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return
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}
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type entityFetcherFunc func(keyID string) (*openpgp.Entity, error)
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func (f entityFetcherFunc) FetchEntity(keyID string) (*openpgp.Entity, error) {
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return f(keyID)
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}
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