/
verify.go
180 lines (158 loc) · 4.88 KB
/
verify.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
package signed
import (
"errors"
"strings"
"time"
"github.com/Sirupsen/logrus"
"github.com/endophage/gotuf/data"
"github.com/endophage/gotuf/keys"
"github.com/jfrazelle/go/canonical/json"
)
// Various basic signing errors
var (
ErrMissingKey = errors.New("tuf: missing key")
ErrNoSignatures = errors.New("tuf: data has no signatures")
ErrInvalid = errors.New("tuf: signature verification failed")
ErrWrongMethod = errors.New("tuf: invalid signature type")
ErrUnknownRole = errors.New("tuf: unknown role")
ErrWrongType = errors.New("tuf: meta file has wrong type")
)
// VerifyRoot checks if a given root file is valid against a known set of keys.
// Threshold is always assumed to be 1
func VerifyRoot(s *data.Signed, minVersion int, keys map[string]data.PublicKey) error {
if len(s.Signatures) == 0 {
return ErrNoSignatures
}
var decoded map[string]interface{}
if err := json.Unmarshal(s.Signed, &decoded); err != nil {
return err
}
msg, err := json.MarshalCanonical(decoded)
if err != nil {
return err
}
for _, sig := range s.Signatures {
// method lookup is consistent due to Unmarshal JSON doing lower case for us.
method := sig.Method
verifier, ok := Verifiers[method]
if !ok {
logrus.Debugf("continuing b/c signing method is not supported for verify root: %s\n", sig.Method)
continue
}
key, ok := keys[sig.KeyID]
if !ok {
logrus.Debugf("continuing b/c signing key isn't present in keys: %s\n", sig.KeyID)
continue
}
if err := verifier.Verify(key, sig.Signature, msg); err != nil {
logrus.Debugf("continuing b/c signature was invalid\n")
continue
}
// threshold of 1 so return on first success
return verifyMeta(s, "root", minVersion)
}
return ErrRoleThreshold{}
}
// Verify checks the signatures and metadata (expiry, version) for the signed role
// data
func Verify(s *data.Signed, role string, minVersion int, db *keys.KeyDB) error {
if err := VerifySignatures(s, role, db); err != nil {
return err
}
return verifyMeta(s, role, minVersion)
}
func verifyMeta(s *data.Signed, role string, minVersion int) error {
sm := &data.SignedCommon{}
if err := json.Unmarshal(s.Signed, sm); err != nil {
return err
}
if !data.ValidTUFType(sm.Type, role) {
return ErrWrongType
}
if IsExpired(sm.Expires) {
logrus.Errorf("Metadata for %s expired", role)
return ErrExpired{Role: role, Expired: sm.Expires.Format("Mon Jan 2 15:04:05 MST 2006")}
}
if sm.Version < minVersion {
return ErrLowVersion{sm.Version, minVersion}
}
return nil
}
// IsExpired checks if the given time passed before the present time
func IsExpired(t time.Time) bool {
return t.Before(time.Now())
}
// VerifySignatures checks the we have sufficient valid signatures for the given role
func VerifySignatures(s *data.Signed, role string, db *keys.KeyDB) error {
if len(s.Signatures) == 0 {
return ErrNoSignatures
}
roleData := db.GetRole(role)
if roleData == nil {
return ErrUnknownRole
}
if roleData.Threshold < 1 {
return ErrRoleThreshold{}
}
logrus.Debugf("%s role has key IDs: %s", role, strings.Join(roleData.KeyIDs, ","))
var decoded map[string]interface{}
if err := json.Unmarshal(s.Signed, &decoded); err != nil {
return err
}
msg, err := json.MarshalCanonical(decoded)
if err != nil {
return err
}
valid := make(map[string]struct{})
for _, sig := range s.Signatures {
logrus.Debug("verifying signature for key ID: ", sig.KeyID)
if !roleData.ValidKey(sig.KeyID) {
logrus.Debugf("continuing b/c keyid was invalid: %s for roledata %s\n", sig.KeyID, roleData)
continue
}
key := db.GetKey(sig.KeyID)
if key == nil {
logrus.Debugf("continuing b/c keyid lookup was nil: %s\n", sig.KeyID)
continue
}
// method lookup is consistent due to Unmarshal JSON doing lower case for us.
method := sig.Method
verifier, ok := Verifiers[method]
if !ok {
logrus.Debugf("continuing b/c signing method is not supported: %s\n", sig.Method)
continue
}
if err := verifier.Verify(key, sig.Signature, msg); err != nil {
logrus.Debugf("continuing b/c signature was invalid\n")
continue
}
valid[sig.KeyID] = struct{}{}
}
if len(valid) < roleData.Threshold {
return ErrRoleThreshold{}
}
return nil
}
// Unmarshal unmarshals and verifys the raw bytes for a given role's metadata
func Unmarshal(b []byte, v interface{}, role string, minVersion int, db *keys.KeyDB) error {
s := &data.Signed{}
if err := json.Unmarshal(b, s); err != nil {
return err
}
if err := Verify(s, role, minVersion, db); err != nil {
return err
}
return json.Unmarshal(s.Signed, v)
}
// UnmarshalTrusted unmarshals and verifies signatures only, not metadata, for a
// given role's metadata
func UnmarshalTrusted(b []byte, v interface{}, role string, db *keys.KeyDB) error {
s := &data.Signed{}
if err := json.Unmarshal(b, s); err != nil {
return err
}
if err := VerifySignatures(s, role, db); err != nil {
return err
}
return json.Unmarshal(s.Signed, v)
}