2019-06-30 17:07:58 -05:00
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// Copyright 2015 Matthew Holt and The Caddy Authors
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//
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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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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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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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2019-05-30 00:11:46 -05:00
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package standardstek
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import (
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"log"
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"sync"
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"time"
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2019-07-02 13:37:06 -05:00
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"github.com/caddyserver/caddy/v2"
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"github.com/caddyserver/caddy/v2/modules/caddytls"
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2019-05-30 00:11:46 -05:00
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)
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func init() {
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2019-08-21 11:46:35 -05:00
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caddy.RegisterModule(standardSTEKProvider{})
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2019-05-30 00:11:46 -05:00
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}
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type standardSTEKProvider struct {
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stekConfig *caddytls.SessionTicketService
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timer *time.Timer
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}
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2019-08-21 11:46:35 -05:00
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// CaddyModule returns the Caddy module information.
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func (standardSTEKProvider) CaddyModule() caddy.ModuleInfo {
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return caddy.ModuleInfo{
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2019-12-10 15:36:46 -05:00
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ID: "tls.stek.standard",
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New: func() caddy.Module { return new(standardSTEKProvider) },
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2019-08-21 11:46:35 -05:00
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}
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}
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2019-05-30 00:11:46 -05:00
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// Initialize sets the configuration for s and returns the starting keys.
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func (s *standardSTEKProvider) Initialize(config *caddytls.SessionTicketService) ([][32]byte, error) {
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2019-06-03 16:35:14 -05:00
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// keep a reference to the config; we'll need it when rotating keys
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2019-05-30 00:11:46 -05:00
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s.stekConfig = config
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itvl := time.Duration(s.stekConfig.RotationInterval)
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mutex.Lock()
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defer mutex.Unlock()
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// if this is our first rotation or we are overdue
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// for one, perform a rotation immediately; otherwise,
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// we assume that the keys are non-empty and fresh
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since := time.Since(lastRotation)
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if lastRotation.IsZero() || since > itvl {
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var err error
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keys, err = s.stekConfig.RotateSTEKs(keys)
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if err != nil {
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return nil, err
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}
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since = 0 // since this is overdue or is the first rotation, use full interval
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lastRotation = time.Now()
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}
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// create timer for the remaining time on the interval;
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// this timer is cleaned up only when Next() returns
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s.timer = time.NewTimer(itvl - since)
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return keys, nil
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}
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// Next returns a channel which transmits the latest session ticket keys.
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func (s *standardSTEKProvider) Next(doneChan <-chan struct{}) <-chan [][32]byte {
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keysChan := make(chan [][32]byte)
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go s.rotate(doneChan, keysChan)
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return keysChan
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}
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// rotate rotates keys on a regular basis, sending each updated set of
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// keys down keysChan, until doneChan is closed.
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func (s *standardSTEKProvider) rotate(doneChan <-chan struct{}, keysChan chan<- [][32]byte) {
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for {
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select {
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case now := <-s.timer.C:
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// copy the slice header to avoid races
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mutex.RLock()
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keysCopy := keys
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mutex.RUnlock()
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// generate a new key, rotating old ones
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var err error
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keysCopy, err = s.stekConfig.RotateSTEKs(keysCopy)
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if err != nil {
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// TODO: improve this handling
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log.Printf("[ERROR] Generating STEK: %v", err)
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continue
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}
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// replace keys slice with updated value and
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// record the timestamp of rotation
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mutex.Lock()
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keys = keysCopy
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lastRotation = now
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mutex.Unlock()
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// send the updated keys to the service
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keysChan <- keysCopy
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// timer channel is already drained, so reset directly (see godoc)
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s.timer.Reset(time.Duration(s.stekConfig.RotationInterval))
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case <-doneChan:
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// again, see godocs for why timer is stopped this way
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if !s.timer.Stop() {
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<-s.timer.C
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}
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return
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}
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}
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}
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var (
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lastRotation time.Time
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keys [][32]byte
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mutex sync.RWMutex // protects keys and lastRotation
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)
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// Interface guard
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var _ caddytls.STEKProvider = (*standardSTEKProvider)(nil)
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