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
|
// 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 standardstek
import (
"log"
"sync"
"time"
"github.com/caddyserver/caddy/v2"
"github.com/caddyserver/caddy/v2/modules/caddytls"
)
func init() {
caddy.RegisterModule(standardSTEKProvider{})
}
type standardSTEKProvider struct {
stekConfig *caddytls.SessionTicketService
timer *time.Timer
}
// CaddyModule returns the Caddy module information.
func (standardSTEKProvider) CaddyModule() caddy.ModuleInfo {
return caddy.ModuleInfo{
ID: "tls.stek.standard",
New: func() caddy.Module { return new(standardSTEKProvider) },
}
}
// Initialize sets the configuration for s and returns the starting keys.
func (s *standardSTEKProvider) Initialize(config *caddytls.SessionTicketService) ([][32]byte, error) {
// keep a reference to the config; we'll need it when rotating keys
s.stekConfig = config
itvl := time.Duration(s.stekConfig.RotationInterval)
mutex.Lock()
defer mutex.Unlock()
// if this is our first rotation or we are overdue
// for one, perform a rotation immediately; otherwise,
// we assume that the keys are non-empty and fresh
since := time.Since(lastRotation)
if lastRotation.IsZero() || since > itvl {
var err error
keys, err = s.stekConfig.RotateSTEKs(keys)
if err != nil {
return nil, err
}
since = 0 // since this is overdue or is the first rotation, use full interval
lastRotation = time.Now()
}
// create timer for the remaining time on the interval;
// this timer is cleaned up only when Next() returns
s.timer = time.NewTimer(itvl - since)
return keys, nil
}
// Next returns a channel which transmits the latest session ticket keys.
func (s *standardSTEKProvider) Next(doneChan <-chan struct{}) <-chan [][32]byte {
keysChan := make(chan [][32]byte)
go s.rotate(doneChan, keysChan)
return keysChan
}
// rotate rotates keys on a regular basis, sending each updated set of
// keys down keysChan, until doneChan is closed.
func (s *standardSTEKProvider) rotate(doneChan <-chan struct{}, keysChan chan<- [][32]byte) {
for {
select {
case now := <-s.timer.C:
// copy the slice header to avoid races
mutex.RLock()
keysCopy := keys
mutex.RUnlock()
// generate a new key, rotating old ones
var err error
keysCopy, err = s.stekConfig.RotateSTEKs(keysCopy)
if err != nil {
// TODO: improve this handling
log.Printf("[ERROR] Generating STEK: %v", err)
continue
}
// replace keys slice with updated value and
// record the timestamp of rotation
mutex.Lock()
keys = keysCopy
lastRotation = now
mutex.Unlock()
// send the updated keys to the service
keysChan <- keysCopy
// timer channel is already drained, so reset directly (see godoc)
s.timer.Reset(time.Duration(s.stekConfig.RotationInterval))
case <-doneChan:
// again, see godocs for why timer is stopped this way
if !s.timer.Stop() {
<-s.timer.C
}
return
}
}
}
var (
lastRotation time.Time
keys [][32]byte
mutex sync.RWMutex // protects keys and lastRotation
)
// Interface guard
var _ caddytls.STEKProvider = (*standardSTEKProvider)(nil)
|
