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
191
192
193
194
195
196
197
198
199
200
201
202
203
204
|
// Copyright 2015 Matthew Holt and The Caddy 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 caddytls
import (
"bytes"
"context"
"crypto/x509"
"encoding/pem"
"time"
"github.com/caddyserver/certmagic"
"github.com/smallstep/certificates/authority/provisioner"
"go.uber.org/zap"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/caddyconfig/caddyfile"
"github.com/caddyserver/caddy/v2/modules/caddypki"
)
func init() {
caddy.RegisterModule(InternalIssuer{})
}
// InternalIssuer is a certificate issuer that generates
// certificates internally using a locally-configured
// CA which can be customized using the `pki` app.
type InternalIssuer struct {
// The ID of the CA to use for signing. The default
// CA ID is "local". The CA can be configured with the
// `pki` app.
CA string `json:"ca,omitempty"`
// The validity period of certificates.
Lifetime caddy.Duration `json:"lifetime,omitempty"`
// If true, the root will be the issuer instead of
// the intermediate. This is NOT recommended and should
// only be used when devices/clients do not properly
// validate certificate chains.
SignWithRoot bool `json:"sign_with_root,omitempty"`
ca *caddypki.CA
logger *zap.Logger
}
// CaddyModule returns the Caddy module information.
func (InternalIssuer) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "tls.issuance.internal",
New: func() caddy.Module { return new(InternalIssuer) },
}
}
// Provision sets up the issuer.
func (iss *InternalIssuer) Provision(ctx caddy.Context) error {
iss.logger = ctx.Logger()
// set some defaults
if iss.CA == "" {
iss.CA = caddypki.DefaultCAID
}
// get a reference to the configured CA
appModule, err := ctx.App("pki")
if err != nil {
return err
}
pkiApp := appModule.(*caddypki.PKI)
ca, err := pkiApp.GetCA(ctx, iss.CA)
if err != nil {
return err
}
iss.ca = ca
// set any other default values
if iss.Lifetime == 0 {
iss.Lifetime = caddy.Duration(defaultInternalCertLifetime)
}
return nil
}
// IssuerKey returns the unique issuer key for the
// confgured CA endpoint.
func (iss InternalIssuer) IssuerKey() string {
return iss.ca.ID
}
// Issue issues a certificate to satisfy the CSR.
func (iss InternalIssuer) Issue(ctx context.Context, csr *x509.CertificateRequest) (*certmagic.IssuedCertificate, error) {
// prepare the signing authority
authCfg := caddypki.AuthorityConfig{
SignWithRoot: iss.SignWithRoot,
}
auth, err := iss.ca.NewAuthority(authCfg)
if err != nil {
return nil, err
}
// get the cert (public key) that will be used for signing
var issuerCert *x509.Certificate
if iss.SignWithRoot {
issuerCert = iss.ca.RootCertificate()
} else {
issuerCert = iss.ca.IntermediateCertificate()
}
// ensure issued certificate does not expire later than its issuer
lifetime := time.Duration(iss.Lifetime)
if time.Now().Add(lifetime).After(issuerCert.NotAfter) {
lifetime = time.Until(issuerCert.NotAfter)
iss.logger.Warn("cert lifetime would exceed issuer NotAfter, clamping lifetime",
zap.Duration("orig_lifetime", time.Duration(iss.Lifetime)),
zap.Duration("lifetime", lifetime),
zap.Time("not_after", issuerCert.NotAfter),
)
}
certChain, err := auth.Sign(csr, provisioner.SignOptions{}, customCertLifetime(caddy.Duration(lifetime)))
if err != nil {
return nil, err
}
var buf bytes.Buffer
for _, cert := range certChain {
err := pem.Encode(&buf, &pem.Block{Type: "CERTIFICATE", Bytes: cert.Raw})
if err != nil {
return nil, err
}
}
return &certmagic.IssuedCertificate{
Certificate: buf.Bytes(),
}, nil
}
// UnmarshalCaddyfile deserializes Caddyfile tokens into iss.
//
// ... internal {
// ca <name>
// lifetime <duration>
// sign_with_root
// }
func (iss *InternalIssuer) UnmarshalCaddyfile(d *caddyfile.Dispenser) error {
d.Next() // consume issuer name
for d.NextBlock(0) {
switch d.Val() {
case "ca":
if !d.AllArgs(&iss.CA) {
return d.ArgErr()
}
case "lifetime":
if !d.NextArg() {
return d.ArgErr()
}
dur, err := caddy.ParseDuration(d.Val())
if err != nil {
return err
}
iss.Lifetime = caddy.Duration(dur)
case "sign_with_root":
if d.NextArg() {
return d.ArgErr()
}
iss.SignWithRoot = true
}
}
return nil
}
// customCertLifetime allows us to customize certificates that are issued
// by Smallstep libs, particularly the NotBefore & NotAfter dates.
type customCertLifetime time.Duration
func (d customCertLifetime) Modify(cert *x509.Certificate, _ provisioner.SignOptions) error {
cert.NotBefore = time.Now()
cert.NotAfter = cert.NotBefore.Add(time.Duration(d))
return nil
}
const defaultInternalCertLifetime = 12 * time.Hour
// Interface guards
var (
_ caddy.Provisioner = (*InternalIssuer)(nil)
_ certmagic.Issuer = (*InternalIssuer)(nil)
_ provisioner.CertificateModifier = (*customCertLifetime)(nil)
)
|
