Newer
Older
package irmago
import (
"encoding/json"
"io/ioutil"
"os"
"strconv"
"crypto/rand"
"encoding/hex"
"math/big"
"path"
)
// Filenames in which we store stuff
const (
skFile = "sk"
attributesFile = "attrs"
kssFile = "kss"
paillierFile = "paillier"
signaturesDir = "sigs"
func PathExists(path string) (bool, error) {
_, err := os.Stat(path)
if err == nil {
return true, nil
}
if os.IsNotExist(err) {
return false, nil
}
return true, err
}
// Init deserializes the credentials from storage.
func (cm *CredentialManager) Init(path string, keyshareHandler KeyshareHandler) (err error) {
cm.storagePath = path
err = cm.ensureStorageExists()
if err != nil {
return err
}
cm.secretkey, err = cm.loadSecretKey()
if err != nil {
return
}
cm.attributes, err = cm.loadAttributes()
if err != nil {
return
}
cm.paillierKeyCache, err = cm.loadPaillierKeys()
if err != nil {
return
}
cm.keyshareServers, err = cm.loadKeyshareServers()
if err != nil {
return
}
unenrolled := cm.unenrolledKeyshareServers()
switch len(unenrolled) {
case 0:
return
case 1:
if keyshareHandler == nil {
return errors.New("Keyshare server found but no KeyshareHandler was given")
keyshareHandler.StartKeyshareRegistration(unenrolled[0], func(email, pin string) {
cm.KeyshareEnroll(unenrolled[0].Identifier(), email, pin)
})
default:
return errors.New("Too many keyshare servers")
}
return nil
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
}
// ParseAndroidStorage parses an Android cardemu.xml shared preferences file
// from the old Android IRMA app, parsing its credentials into the current instance,
// and saving them to storage.
// CAREFUL: this method overwrites any existing secret keys and attributes on storage.
func (cm *CredentialManager) ParseAndroidStorage() (err error) {
exists, err := PathExists(cm.path(cardemuXML))
if err != nil || !exists {
return
}
bytes, err := ioutil.ReadFile(cm.path(cardemuXML))
parsedxml := struct {
Strings []struct {
Name string `xml:"name,attr"`
Content string `xml:",chardata"`
} `xml:"string"`
}{}
xml.Unmarshal(bytes, &parsedxml)
parsedjson := make(map[string][]*gabi.Credential)
parsedksses := make(map[string]*keyshareServer)
for _, xmltag := range parsedxml.Strings {
if xmltag.Name == "credentials" {
jsontag := html.UnescapeString(xmltag.Content)
if err = json.Unmarshal([]byte(jsontag), &parsedjson); err != nil {
return
}
}
if xmltag.Name == "keyshare" {
jsontag := html.UnescapeString(xmltag.Content)
if err = json.Unmarshal([]byte(jsontag), &parsedksses); err != nil {
return
}
}
if xmltag.Name == "KeyshareKeypairs" {
jsontag := html.UnescapeString(xmltag.Content)
keys := make([]*paillierPrivateKey, 0, 3)
if err = json.Unmarshal([]byte(jsontag), &keys); err != nil {
return
}
cm.paillierKeyCache = keys[0]
}
}
for name, kss := range parsedksses {
cm.keyshareServers[NewSchemeManagerIdentifier(name)] = kss
}
for _, list := range parsedjson {
cm.secretkey = list[0].Attributes[0]
for i, gabicred := range list {
cred := newCredential(gabicred)
if cred.CredentialType() == nil {
return errors.New("cannot add unknown credential type")
}
cm.addCredential(cred)
err = cm.storeSignature(cred, i)
if err != nil {
return err
}
}
}
if len(cm.credentials) > 0 {
err = cm.storeAttributes()
if err != nil {
return err
}
err = cm.storeSecretKey(cm.secretkey)
if err != nil {
return err
}
}
if len(cm.keyshareServers) > 0 {
err = cm.storeKeyshareServers()
if err != nil {
return err
}
}
err = cm.storePaillierKeys()
if err != nil {
return err
}
if cm.paillierKeyCache == nil {
cm.paillierKey() // trigger calculating a new one
}
return
}
func (cm *CredentialManager) path(file string) string {
return cm.storagePath + "/" + file
}
func (cm *CredentialManager) signatureFilename(id string, counter int) string {
return cm.path(signaturesDir) + "/" + id + "-" + strconv.Itoa(counter)
}
// ensureStorageExists initializes the credential storage folder,
// ensuring that it is in a usable state.
// NOTE: we do not create the folder if it does not exist!
// Setting it up in a properly protected location (e.g., with automatic
// backups to iCloud/Google disabled) is the responsibility of the user.
func (cm *CredentialManager) ensureStorageExists() (err error) {
exist, err := PathExists(cm.storagePath)
if err != nil {
return
}
if !exist {
return errors.New("credential storage path does not exist")
}
exist, err = PathExists(cm.path(signaturesDir))
if err != nil {
return err
}
if !exist {
err = os.Mkdir(cm.path(signaturesDir), 0700)
}
return
}
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
func (cm *CredentialManager) storeSecretKey(sk *big.Int) error {
return ioutil.WriteFile(cm.path(skFile), sk.Bytes(), 0600)
}
// Save the filecontents at the specified path atomically:
// - first save the content in a temp file with a random filename in the same dir
// - then rename the temp file to the specified filepath, overwriting the old file
func (cm *CredentialManager) saveFile(filepath string, content []byte) (err error) {
dir := path.Dir(filepath)
// Read random data for filename and convert to hex
randBytes := make([]byte, 16)
_, err = rand.Read(randBytes)
if err != nil {
return
}
tempfilename := hex.EncodeToString(randBytes)
// Create temp file
err = ioutil.WriteFile(dir+"/"+tempfilename, content, 0600)
if err != nil {
return
}
// Rename, overwriting old file
return os.Rename(dir+"/"+tempfilename, filepath)
func (cm *CredentialManager) storeSignature(cred *credential, counter int) (err error) {
if cred.CredentialType() == nil {
return errors.New("cannot add unknown credential type")
}
credbytes, err := json.Marshal(cred.Signature)
if err != nil {
return err
}
// TODO existence check
filename := cm.signatureFilename(cred.CredentialType().Identifier().String(), counter)
err = ioutil.WriteFile(filename, credbytes, 0600)
return
}
func (cm *CredentialManager) storeAttributes() (err error) {
// Unfortunately, the type of cm.attributes (map[CredentialTypeIdentifier][]*AttributeList)
// cannot be passed directly to json.Marshal(), so we copy it into a temp list.
temp := make(map[string][]*AttributeList)
for credid, list := range cm.attributes {
temp[credid.String()] = list
}
attrbytes, err := json.Marshal(temp)
if err != nil {
return err
}
// TODO existence check
err = ioutil.WriteFile(cm.path(attributesFile), attrbytes, 0600)
return
}
func (cm *CredentialManager) storeKeyshareServers() (err error) {
temp := make(map[string]*keyshareServer)
for name, kss := range cm.keyshareServers {
temp[name.String()] = kss
}
bts, err := json.Marshal(temp)
if err != nil {
return
}
err = ioutil.WriteFile(cm.path(kssFile), bts, 0600)
return
}
func (cm *CredentialManager) storePaillierKeys() (err error) {
bts, err := json.Marshal(cm.paillierKeyCache)
if err != nil {
return
}
err = ioutil.WriteFile(cm.path(paillierFile), bts, 0600)
return
}
func (cm *CredentialManager) loadSignature(id CredentialTypeIdentifier, counter int) (signature *gabi.CLSignature, err error) {
sigpath := cm.signatureFilename(id.String(), counter)
exists, err := PathExists(sigpath)
if err != nil {
return
}
signature = new(gabi.CLSignature)
err = json.Unmarshal(bytes, signature)
return
}
// loadSecretKey retrieves and returns the secret key from storage, or if no secret key
// was found in storage, it generates, saves, and returns a new secret key.
func (cm *CredentialManager) loadSecretKey() (*big.Int, error) {
exists, err := PathExists(cm.path(skFile))
if err != nil {
return nil, err
}
if exists {
var bytes []byte
if bytes, err = ioutil.ReadFile(cm.path(skFile)); err == nil {
return new(big.Int).SetBytes(bytes), nil
sk, err := cm.generateSecretKey()
if err != nil {
return nil, err
}
err = cm.storeSecretKey(sk)
if err != nil {
return nil, err
}
return sk, nil
func (cm *CredentialManager) loadAttributes() (list map[CredentialTypeIdentifier][]*AttributeList, err error) {
list = make(map[CredentialTypeIdentifier][]*AttributeList)
temp := make(map[string][]*AttributeList)
exists, err := PathExists(cm.path(attributesFile))
if err != nil || !exists {
return
}
bytes, err := ioutil.ReadFile(cm.path(attributesFile))
if err != nil {
return nil, err
}
err = json.Unmarshal(bytes, &temp)
if err != nil {
return nil, err
}
for credid, attrs := range temp {
list[NewCredentialTypeIdentifier(credid)] = attrs
}
return list, nil
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
func (cm *CredentialManager) loadKeyshareServers() (ksses map[SchemeManagerIdentifier]*keyshareServer, err error) {
ksses = make(map[SchemeManagerIdentifier]*keyshareServer)
temp := make(map[string]*keyshareServer)
exists, err := PathExists(cm.path(kssFile))
if err != nil || !exists {
return
}
bytes, err := ioutil.ReadFile(cm.path(kssFile))
if err != nil {
return nil, err
}
err = json.Unmarshal(bytes, &temp)
if err != nil {
return nil, err
}
for name, kss := range temp {
ksses[NewSchemeManagerIdentifier(name)] = kss
}
return
}
func (cm *CredentialManager) loadPaillierKeys() (key *paillierPrivateKey, err error) {
exists, err := PathExists(cm.path(paillierFile))
if err != nil || !exists {
return
}
bytes, err := ioutil.ReadFile(cm.path(paillierFile))
if err != nil {
return nil, err
}
key = new(paillierPrivateKey)
err = json.Unmarshal(bytes, key)
if err != nil {
return nil, err
}
return
}