-
Notifications
You must be signed in to change notification settings - Fork 38
/
timestamp.go
190 lines (165 loc) · 6.04 KB
/
timestamp.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
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
// Copyright 2022 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 api
import (
"bytes"
"crypto"
"encoding/asn1"
"encoding/base64"
"encoding/json"
"fmt"
"io"
"math/big"
"net/http"
"strconv"
"strings"
"time"
"github.com/digitorus/timestamp"
"github.com/go-openapi/runtime/middleware"
"github.com/pkg/errors"
ts "github.com/sigstore/timestamp-authority/pkg/generated/restapi/operations/timestamp"
"github.com/sigstore/timestamp-authority/pkg/verification"
)
type JSONRequest struct {
ArtifactHash string `json:"artifactHash"`
Certificates bool `json:"certificates"`
HashAlgorithm string `json:"hashAlgorithm"`
Nonce *big.Int `json:"nonce"`
TSAPolicyOID string `json:"tsaPolicyOID"`
}
func getHashAlg(alg string) (crypto.Hash, string, error) {
lowercaseAlg := strings.ToLower(alg)
switch lowercaseAlg {
case "sha256":
return crypto.SHA256, "", nil
case "sha384":
return crypto.SHA384, "", nil
case "sha512":
return crypto.SHA512, "", nil
case "sha1":
return 0, WeakHashAlgorithmTimestampRequest, verification.ErrWeakHashAlg
default:
return 0, failedToGenerateTimestampResponse, fmt.Errorf("unsupported hash algorithm: %s", alg)
}
}
// ParseJSONRequest parses a JSON request into a timestamp.Request struct
func ParseJSONRequest(reqBytes []byte) (*timestamp.Request, string, error) {
// unmarshal the request bytes into a JSONRequest struct
var req JSONRequest
if err := json.Unmarshal(reqBytes, &req); err != nil {
return nil, failedToGenerateTimestampResponse, fmt.Errorf("failed to parse JSON into request: %v", err)
}
// after unmarshalling, parse the JSONRequest.Artifact into a Reader and parse the remaining
// fields into a a timestamp.RequestOptions struct
hashAlgo, errMsg, err := getHashAlg(req.HashAlgorithm)
if err != nil {
return nil, errMsg, fmt.Errorf("failed to parse hash algorithm: %v", err)
}
var oidInts []int
if req.TSAPolicyOID == "" {
oidInts = nil
} else {
for _, v := range strings.Split(req.TSAPolicyOID, ".") {
i, _ := strconv.Atoi(v)
oidInts = append(oidInts, i)
}
}
// decode the base64 encoded artifact hash
decoded, err := base64.StdEncoding.DecodeString(req.ArtifactHash)
if err != nil {
return nil, failedToGenerateTimestampResponse, fmt.Errorf("failed to decode base64 encoded artifact hash: %v", err)
}
// create a timestamp request from the request's JSON body
tsReq := timestamp.Request{
HashAlgorithm: hashAlgo,
HashedMessage: decoded,
Certificates: req.Certificates,
Nonce: req.Nonce,
TSAPolicyOID: oidInts,
}
return &tsReq, "", nil
}
func parseDERRequest(reqBytes []byte) (*timestamp.Request, string, error) {
parsed, err := timestamp.ParseRequest(reqBytes)
if err != nil {
return nil, failedToGenerateTimestampResponse, err
}
// verify that the request's hash algorithm is supported
if err := verification.VerifyRequest(parsed); err != nil {
return nil, WeakHashAlgorithmTimestampRequest, err
}
return parsed, "", nil
}
func getContentType(r *http.Request) (string, error) {
contentTypeHeader := r.Header.Get("Content-Type")
splitHeader := strings.Split(contentTypeHeader, "application/")
if len(splitHeader) != 2 {
return "", errors.New("expected header value to be split into two pieces")
}
return splitHeader[1], nil
}
func requestBodyToTimestampReq(reqBytes []byte, contentType string) (*timestamp.Request, string, error) {
switch contentType {
case "json":
return ParseJSONRequest(reqBytes)
case "timestamp-query":
return parseDERRequest(reqBytes)
default:
return nil, failedToGenerateTimestampResponse, fmt.Errorf("unsupported content type")
}
}
func TimestampResponseHandler(params ts.GetTimestampResponseParams) middleware.Responder {
requestBytes, err := io.ReadAll(params.Request)
if err != nil {
return handleTimestampAPIError(params, http.StatusBadRequest, err, failedToGenerateTimestampResponse)
}
contentType, err := getContentType(params.HTTPRequest)
if err != nil {
return handleTimestampAPIError(params, http.StatusUnsupportedMediaType, err, failedToGenerateTimestampResponse)
}
req, errMsg, err := requestBodyToTimestampReq(requestBytes, contentType)
if err != nil {
return handleTimestampAPIError(params, http.StatusBadRequest, err, errMsg)
}
policyID := req.TSAPolicyOID
if policyID.String() == "" {
policyID = asn1.ObjectIdentifier{1, 3, 6, 1, 4, 1, 57264, 2}
}
duration, _ := time.ParseDuration("1s")
tsStruct := timestamp.Timestamp{
HashAlgorithm: req.HashAlgorithm,
HashedMessage: req.HashedMessage,
// The field here is going to be serialized as a GeneralizedTime, and RFC5280
// states that the GeneralizedTime values MUST be expressed in Greenwich Mean Time.
// However, go asn1/marshal will happily accept other formats. So we force it directly here.
// https://datatracker.ietf.org/doc/html/rfc5280#section-4.1.2.5.2
Time: time.Now().UTC(),
Nonce: req.Nonce,
Policy: policyID,
Ordering: false,
Accuracy: duration,
// Not qualified for the european directive
Qualified: false,
AddTSACertificate: req.Certificates,
ExtraExtensions: req.Extensions,
}
resp, err := tsStruct.CreateResponseWithOpts(api.certChain[0], api.tsaSigner, api.tsaSignerHash)
if err != nil {
return handleTimestampAPIError(params, http.StatusInternalServerError, err, failedToGenerateTimestampResponse)
}
return ts.NewGetTimestampResponseCreated().WithPayload(io.NopCloser(bytes.NewReader(resp)))
}
func GetTimestampCertChainHandler(_ ts.GetTimestampCertChainParams) middleware.Responder {
return ts.NewGetTimestampCertChainOK().WithPayload(api.certChainPem)
}