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
|
package stfe
import (
"context"
"fmt"
"reflect"
"sync"
"github.com/golang/glog"
"github.com/google/certificate-transparency-go/schedule"
"github.com/google/trillian"
"github.com/google/trillian/types"
)
// SthSource provides access to the log's STHs.
type SthSource interface {
// Latest returns the most reccent signed_tree_head_v*.
Latest(context.Context) (*StItem, error)
// Stable returns the most recent signed_tree_head_v* that is stable for
// some period of time, e.g., 10 minutes.
Stable(context.Context) (*StItem, error)
// Cosigned returns the most recent cosigned_tree_head_v*.
Cosigned(context.Context) (*StItem, error)
// AddCosignature attempts to add a cosignature to the stable STH. The
// passed cosigned_tree_head_v* must have a single verified cosignature.
AddCosignature(context.Context, *StItem) error
// Run keeps the STH source updated until cancelled
Run(context.Context)
}
// ActiveSthSource implements the SthSource interface for an STFE instance that
// accepts new logging requests, i.e., the log is running in read+write mode.
type ActiveSthSource struct {
client trillian.TrillianLogClient
logParameters *LogParameters
currCosth *StItem // current cosigned_tree_head_v1 (already finalized)
nextCosth *StItem // next cosigned_tree_head_v1 (under preparation)
cosignatureFrom map[string]bool // track who we got cosignatures from in nextCosth
mutex sync.RWMutex
}
// NewActiveSthSource returns an initialized ActiveSthSource
func NewActiveSthSource(cli trillian.TrillianLogClient, lp *LogParameters) (*ActiveSthSource, error) {
s := ActiveSthSource{
client: cli,
logParameters: lp,
}
ctx, _ := context.WithTimeout(context.Background(), lp.Deadline)
sth, err := s.Latest(ctx)
if err != nil {
return nil, fmt.Errorf("Latest: %v", err)
}
// TODO: load persisted cosigned STH?
s.currCosth = NewCosignedTreeHeadV1(sth.SignedTreeHeadV1, nil)
s.nextCosth = NewCosignedTreeHeadV1(sth.SignedTreeHeadV1, nil)
s.cosignatureFrom = make(map[string]bool)
return &s, nil
}
func (s *ActiveSthSource) Run(ctx context.Context) {
schedule.Every(ctx, s.logParameters.Interval, func(ctx context.Context) {
// get the next stable sth
ictx, _ := context.WithTimeout(ctx, s.logParameters.Deadline)
sth, err := s.Latest(ictx)
if err != nil {
glog.Warningf("cannot rotate without new sth: Latest: %v", err)
return
}
// rotate
s.mutex.Lock()
defer s.mutex.Unlock()
s.rotate(sth)
// TODO: persist cosigned STH?
})
}
func (s *ActiveSthSource) Latest(ctx context.Context) (*StItem, error) {
trsp, err := s.client.GetLatestSignedLogRoot(ctx, &trillian.GetLatestSignedLogRootRequest{
LogId: s.logParameters.TreeId,
})
var lr types.LogRootV1
if errInner := checkGetLatestSignedLogRoot(s.logParameters, trsp, err, &lr); errInner != nil {
return nil, fmt.Errorf("invalid signed log root response: %v", errInner)
}
return s.logParameters.genV1Sth(NewTreeHeadV1(&lr))
}
func (s *ActiveSthSource) Stable(_ context.Context) (*StItem, error) {
s.mutex.RLock()
defer s.mutex.RUnlock()
if s.nextCosth == nil {
return nil, fmt.Errorf("no stable sth available")
}
return &StItem{
Format: StFormatSignedTreeHeadV1,
SignedTreeHeadV1: &s.nextCosth.CosignedTreeHeadV1.SignedTreeHeadV1,
}, nil
}
func (s *ActiveSthSource) Cosigned(_ context.Context) (*StItem, error) {
s.mutex.RLock()
defer s.mutex.RUnlock()
if s.currCosth == nil || len(s.currCosth.CosignedTreeHeadV1.SignatureV1) == 0 {
return nil, fmt.Errorf("no cosigned sth available")
}
return s.currCosth, nil
}
func (s *ActiveSthSource) AddCosignature(_ context.Context, costh *StItem) error {
s.mutex.Lock()
defer s.mutex.Unlock()
if !reflect.DeepEqual(s.nextCosth.CosignedTreeHeadV1.SignedTreeHeadV1, costh.CosignedTreeHeadV1.SignedTreeHeadV1) {
return fmt.Errorf("cosignature covers a different tree head")
}
witness := costh.CosignedTreeHeadV1.SignatureV1[0].Namespace.String()
if _, ok := s.cosignatureFrom[witness]; ok {
return nil // duplicate
}
s.cosignatureFrom[witness] = true
s.nextCosth.CosignedTreeHeadV1.SignatureV1 = append(s.nextCosth.CosignedTreeHeadV1.SignatureV1, costh.CosignedTreeHeadV1.SignatureV1[0])
return nil
}
// rotate rotates the log's cosigned and stable STH. The caller must aquire the
// source's read-write lock if there are concurrent reads and/or writes.
func (s *ActiveSthSource) rotate(fixedSth *StItem) {
// rotate stable -> cosigned
if reflect.DeepEqual(&s.currCosth.CosignedTreeHeadV1.SignedTreeHeadV1, &s.nextCosth.CosignedTreeHeadV1.SignedTreeHeadV1) {
for _, sigv1 := range s.currCosth.CosignedTreeHeadV1.SignatureV1 {
witness := sigv1.Namespace.String()
if _, ok := s.cosignatureFrom[witness]; !ok {
s.cosignatureFrom[witness] = true
s.nextCosth.CosignedTreeHeadV1.SignatureV1 = append(s.nextCosth.CosignedTreeHeadV1.SignatureV1, sigv1)
}
}
}
s.currCosth.CosignedTreeHeadV1.SignedTreeHeadV1 = s.nextCosth.CosignedTreeHeadV1.SignedTreeHeadV1
s.currCosth.CosignedTreeHeadV1.SignatureV1 = make([]SignatureV1, len(s.nextCosth.CosignedTreeHeadV1.SignatureV1))
copy(s.currCosth.CosignedTreeHeadV1.SignatureV1, s.nextCosth.CosignedTreeHeadV1.SignatureV1)
// rotate new stable -> stable
if !reflect.DeepEqual(&s.nextCosth.CosignedTreeHeadV1.SignedTreeHeadV1, fixedSth.SignedTreeHeadV1) {
s.nextCosth = NewCosignedTreeHeadV1(fixedSth.SignedTreeHeadV1, nil)
s.cosignatureFrom = make(map[string]bool)
}
}
|
