-
Notifications
You must be signed in to change notification settings - Fork 503
/
attestor.go
89 lines (75 loc) · 2.49 KB
/
attestor.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
// Copyright 2021 The Sigstore Authors.
//
// 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 payload
import (
"context"
"crypto"
"encoding/base64"
"encoding/json"
"io"
"github.com/secure-systems-lab/go-securesystemslib/dsse"
"github.com/sigstore/cosign/v2/internal/pkg/cosign"
"github.com/sigstore/cosign/v2/pkg/oci"
"github.com/sigstore/cosign/v2/pkg/oci/static"
"github.com/sigstore/cosign/v2/pkg/types"
"github.com/sigstore/sigstore/pkg/signature"
)
type payloadAttestor struct {
signer payloadSigner
payloadType string
}
var _ cosign.DSSEAttestor = (*payloadAttestor)(nil)
// Attest implements `cosign.DSSEAttestor`
func (pa *payloadAttestor) DSSEAttest(ctx context.Context, payload io.Reader) (oci.Signature, crypto.PublicKey, error) {
p, err := io.ReadAll(payload)
if err != nil {
return nil, nil, err
}
pb := dsse.PAE(pa.payloadType, p)
sig, err := pa.signer.signPayload(ctx, pb)
if err != nil {
return nil, nil, err
}
pk, err := pa.signer.publicKey(ctx)
if err != nil {
return nil, nil, err
}
envelope := dsse.Envelope{
PayloadType: pa.payloadType,
Payload: base64.StdEncoding.EncodeToString(pb),
Signatures: []dsse.Signature{{
Sig: base64.StdEncoding.EncodeToString(sig),
}},
}
envelopeJSON, err := json.Marshal(envelope)
if err != nil {
return nil, nil, err
}
opts := []static.Option{static.WithLayerMediaType(types.DssePayloadType)}
att, err := static.NewAttestation(envelopeJSON, opts...)
if err != nil {
return nil, nil, err
}
return att, pk, nil
}
// NewDSSEAttestor returns a `cosign.DSSEAttestor` which uses the given `signature.Signer` to sign and create a DSSE attestation of given payloads.
// Option types other than `signature.SignOption` and `signature.PublicKeyOption` cause a runtime panic.
func NewDSSEAttestor(payloadType string,
s signature.Signer,
signAndPublicKeyOptions ...interface{}) cosign.DSSEAttestor {
return &payloadAttestor{
signer: newSigner(s, signAndPublicKeyOptions...),
payloadType: payloadType,
}
}