1/*
2 * Copyright (C) 2016 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#define LOG_TAG "keystore"
18
19#include "keystore.h"
20
21#include <dirent.h>
22#include <fcntl.h>
23
24#include <openssl/bio.h>
25
26#include <utils/String16.h>
27#include <utils/String8.h>
28
29#include <keystore/IKeystoreService.h>
30
31#include <android/hardware/keymaster/3.0/IKeymasterDevice.h>
32
33#include "keystore_utils.h"
34#include "permissions.h"
35#include <keystore/keystore_hidl_support.h>
36
37const char* KeyStore::sOldMasterKey = ".masterkey";
38const char* KeyStore::sMetaDataFile = ".metadata";
39
40const android::String16 KeyStore::sRSAKeyType("RSA");
41
42using namespace keystore;
43using android::String8;
44
45KeyStore::KeyStore(Entropy* entropy, const km_device_t& device, const km_device_t& fallback,
46                   bool allowNewFallback)
47    : mEntropy(entropy), mDevice(device), mFallbackDevice(fallback),
48      mAllowNewFallback(allowNewFallback) {
49    memset(&mMetaData, '\0', sizeof(mMetaData));
50}
51
52KeyStore::~KeyStore() {
53    for (android::Vector<UserState*>::iterator it(mMasterKeys.begin()); it != mMasterKeys.end();
54         it++) {
55        delete *it;
56    }
57    mMasterKeys.clear();
58}
59
60ResponseCode KeyStore::initialize() {
61    readMetaData();
62    if (upgradeKeystore()) {
63        writeMetaData();
64    }
65
66    return ResponseCode::NO_ERROR;
67}
68
69ResponseCode KeyStore::initializeUser(const android::String8& pw, uid_t userId) {
70    UserState* userState = getUserState(userId);
71    return userState->initialize(pw, mEntropy);
72}
73
74ResponseCode KeyStore::copyMasterKey(uid_t srcUser, uid_t dstUser) {
75    UserState* userState = getUserState(dstUser);
76    UserState* initState = getUserState(srcUser);
77    return userState->copyMasterKey(initState);
78}
79
80ResponseCode KeyStore::writeMasterKey(const android::String8& pw, uid_t userId) {
81    UserState* userState = getUserState(userId);
82    return userState->writeMasterKey(pw, mEntropy);
83}
84
85ResponseCode KeyStore::readMasterKey(const android::String8& pw, uid_t userId) {
86    UserState* userState = getUserState(userId);
87    return userState->readMasterKey(pw, mEntropy);
88}
89
90/* Here is the encoding of keys. This is necessary in order to allow arbitrary
91 * characters in keys. Characters in [0-~] are not encoded. Others are encoded
92 * into two bytes. The first byte is one of [+-.] which represents the first
93 * two bits of the character. The second byte encodes the rest of the bits into
94 * [0-o]. Therefore in the worst case the length of a key gets doubled. Note
95 * that Base64 cannot be used here due to the need of prefix match on keys. */
96
97static size_t encode_key_length(const android::String8& keyName) {
98    const uint8_t* in = reinterpret_cast<const uint8_t*>(keyName.string());
99    size_t length = keyName.length();
100    for (int i = length; i > 0; --i, ++in) {
101        if (*in < '0' || *in > '~') {
102            ++length;
103        }
104    }
105    return length;
106}
107
108static int encode_key(char* out, const android::String8& keyName) {
109    const uint8_t* in = reinterpret_cast<const uint8_t*>(keyName.string());
110    size_t length = keyName.length();
111    for (int i = length; i > 0; --i, ++in, ++out) {
112        if (*in < '0' || *in > '~') {
113            *out = '+' + (*in >> 6);
114            *++out = '0' + (*in & 0x3F);
115            ++length;
116        } else {
117            *out = *in;
118        }
119    }
120    *out = '\0';
121    return length;
122}
123
124android::String8 KeyStore::getKeyName(const android::String8& keyName, const BlobType type) {
125    std::vector<char> encoded(encode_key_length(keyName) + 1);  // add 1 for null char
126    encode_key(encoded.data(), keyName);
127    if (type == TYPE_KEY_CHARACTERISTICS) {
128        return android::String8::format(".chr_%s", encoded.data());
129    } else {
130        return android::String8(encoded.data());
131    }
132}
133
134android::String8 KeyStore::getKeyNameForUid(
135    const android::String8& keyName, uid_t uid, const BlobType type) {
136    std::vector<char> encoded(encode_key_length(keyName) + 1);  // add 1 for null char
137    encode_key(encoded.data(), keyName);
138    if (type == TYPE_KEY_CHARACTERISTICS) {
139        return android::String8::format(".%u_chr_%s", uid, encoded.data());
140    } else {
141        return android::String8::format("%u_%s", uid, encoded.data());
142    }
143}
144
145android::String8 KeyStore::getKeyNameForUidWithDir(
146    const android::String8& keyName, uid_t uid, const BlobType type) {
147    std::vector<char> encoded(encode_key_length(keyName) + 1);  // add 1 for null char
148    encode_key(encoded.data(), keyName);
149
150    if (type == TYPE_KEY_CHARACTERISTICS) {
151        return android::String8::format("%s/.%u_chr_%s", getUserStateByUid(uid)->getUserDirName(),
152                                        uid, encoded.data());
153    } else {
154        return android::String8::format("%s/%u_%s", getUserStateByUid(uid)->getUserDirName(), uid,
155                                        encoded.data());
156    }
157}
158
159NullOr<android::String8> KeyStore::getBlobFileNameIfExists(const android::String8& alias, uid_t uid,
160                                                          const BlobType type) {
161    android::String8 filepath8(getKeyNameForUidWithDir(alias, uid, type));
162
163    if (!access(filepath8.string(), R_OK | W_OK)) return filepath8;
164
165    // If this is one of the legacy UID->UID mappings, use it.
166    uid_t euid = get_keystore_euid(uid);
167    if (euid != uid) {
168        filepath8 = getKeyNameForUidWithDir(alias, euid, type);
169        if (!access(filepath8.string(), R_OK | W_OK)) return filepath8;
170    }
171
172    // They might be using a granted key.
173    auto grant = mGrants.get(uid, alias.string());
174    if (grant) {
175        filepath8 = String8::format("%s/%s", grant->owner_dir_name_.c_str(),
176                getKeyNameForUid(String8(grant->alias_.c_str()), grant->owner_uid_, type).c_str());
177        if (!access(filepath8.string(), R_OK | W_OK)) return filepath8;
178    }
179    return {};
180}
181
182
183void KeyStore::resetUser(uid_t userId, bool keepUnenryptedEntries) {
184    android::String8 prefix("");
185    android::Vector<android::String16> aliases;
186    UserState* userState = getUserState(userId);
187    if (list(prefix, &aliases, userId) != ResponseCode::NO_ERROR) {
188        return;
189    }
190    for (uint32_t i = 0; i < aliases.size(); i++) {
191        android::String8 filename(aliases[i]);
192        filename = android::String8::format("%s/%s", userState->getUserDirName(),
193                                            getKeyName(filename, TYPE_ANY).string());
194        bool shouldDelete = true;
195        if (keepUnenryptedEntries) {
196            Blob blob;
197            ResponseCode rc = get(filename, &blob, ::TYPE_ANY, userId);
198
199            switch (rc) {
200            case ResponseCode::SYSTEM_ERROR:
201            case ResponseCode::VALUE_CORRUPTED:
202                // If we can't read blobs, delete them.
203                shouldDelete = true;
204                break;
205
206            case ResponseCode::NO_ERROR:
207            case ResponseCode::LOCKED:
208                // Delete encrypted blobs but keep unencrypted blobs and super-encrypted blobs.  We
209                // need to keep super-encrypted blobs so we can report that the user is
210                // unauthenticated if a caller tries to use them, rather than reporting that they
211                // don't exist.
212                shouldDelete = blob.isEncrypted();
213                break;
214
215            default:
216                ALOGE("Got unexpected return code %d from KeyStore::get()", rc);
217                // This shouldn't happen.  To be on the safe side, delete it.
218                shouldDelete = true;
219                break;
220            }
221        }
222        if (shouldDelete) {
223            del(filename, ::TYPE_ANY, userId);
224
225            // del() will fail silently if no cached characteristics are present for this alias.
226            android::String8 chr_filename(aliases[i]);
227            chr_filename = android::String8::format("%s/%s", userState->getUserDirName(),
228                                            getKeyName(chr_filename,
229                                                TYPE_KEY_CHARACTERISTICS).string());
230            del(chr_filename, ::TYPE_KEY_CHARACTERISTICS, userId);
231        }
232    }
233    if (!userState->deleteMasterKey()) {
234        ALOGE("Failed to delete user %d's master key", userId);
235    }
236    if (!keepUnenryptedEntries) {
237        if (!userState->reset()) {
238            ALOGE("Failed to remove user %d's directory", userId);
239        }
240    }
241}
242
243bool KeyStore::isEmpty(uid_t userId) const {
244    const UserState* userState = getUserState(userId);
245    if (userState == NULL) {
246        return true;
247    }
248
249    DIR* dir = opendir(userState->getUserDirName());
250    if (!dir) {
251        return true;
252    }
253
254    bool result = true;
255    struct dirent* file;
256    while ((file = readdir(dir)) != NULL) {
257        // We only care about files.
258        if (file->d_type != DT_REG) {
259            continue;
260        }
261
262        // Skip anything that starts with a "."
263        if (file->d_name[0] == '.') {
264            continue;
265        }
266
267        result = false;
268        break;
269    }
270    closedir(dir);
271    return result;
272}
273
274void KeyStore::lock(uid_t userId) {
275    UserState* userState = getUserState(userId);
276    userState->zeroizeMasterKeysInMemory();
277    userState->setState(STATE_LOCKED);
278}
279
280ResponseCode KeyStore::get(const char* filename, Blob* keyBlob, const BlobType type, uid_t userId) {
281    UserState* userState = getUserState(userId);
282    ResponseCode rc =
283        keyBlob->readBlob(filename, userState->getEncryptionKey(), userState->getState());
284    if (rc != ResponseCode::NO_ERROR) {
285        return rc;
286    }
287
288    const uint8_t version = keyBlob->getVersion();
289    if (version < CURRENT_BLOB_VERSION) {
290        /* If we upgrade the key, we need to write it to disk again. Then
291         * it must be read it again since the blob is encrypted each time
292         * it's written.
293         */
294        if (upgradeBlob(filename, keyBlob, version, type, userId)) {
295            if ((rc = this->put(filename, keyBlob, userId)) != ResponseCode::NO_ERROR ||
296                (rc = keyBlob->readBlob(filename, userState->getEncryptionKey(),
297                                        userState->getState())) != ResponseCode::NO_ERROR) {
298                return rc;
299            }
300        }
301    }
302
303    /*
304     * This will upgrade software-backed keys to hardware-backed keys.
305     */
306    if (rc == ResponseCode::NO_ERROR && type == TYPE_KEY_PAIR && keyBlob->isFallback()) {
307        ResponseCode imported =
308            importKey(keyBlob->getValue(), keyBlob->getLength(), filename, userId,
309                      keyBlob->isEncrypted() ? KEYSTORE_FLAG_ENCRYPTED : KEYSTORE_FLAG_NONE);
310
311        // The HAL allowed the import, reget the key to have the "fresh" version.
312        if (imported == ResponseCode::NO_ERROR) {
313            rc = get(filename, keyBlob, TYPE_KEY_PAIR, userId);
314        }
315    }
316
317    // Keymaster 0.3 keys are valid keymaster 1.0 keys, so silently upgrade.
318    if (keyBlob->getType() == TYPE_KEY_PAIR) {
319        keyBlob->setType(TYPE_KEYMASTER_10);
320        rc = this->put(filename, keyBlob, userId);
321    }
322
323    if (type != TYPE_ANY && keyBlob->getType() != type) {
324        ALOGW("key found but type doesn't match: %d vs %d", keyBlob->getType(), type);
325        return ResponseCode::KEY_NOT_FOUND;
326    }
327
328    return rc;
329}
330
331ResponseCode KeyStore::put(const char* filename, Blob* keyBlob, uid_t userId) {
332    UserState* userState = getUserState(userId);
333    return keyBlob->writeBlob(filename, userState->getEncryptionKey(), userState->getState(),
334                              mEntropy);
335}
336
337static NullOr<std::tuple<uid_t, std::string>> filename2UidAlias(const std::string& filename);
338
339ResponseCode KeyStore::del(const char* filename, const BlobType type, uid_t userId) {
340    Blob keyBlob;
341    auto uidAlias = filename2UidAlias(filename);
342    uid_t uid;
343    std::string alias;
344    if (uidAlias.isOk()) {
345        std::tie(uid, alias) = std::move(uidAlias).value();
346    }
347    ResponseCode rc = get(filename, &keyBlob, type, userId);
348    if (rc == ResponseCode::VALUE_CORRUPTED) {
349        // The file is corrupt, the best we can do is rm it.
350        if (uidAlias.isOk()) {
351            // remove possible grants
352            mGrants.removeAllGrantsToKey(uid, alias);
353        }
354        return (unlink(filename) && errno != ENOENT) ?
355                ResponseCode::SYSTEM_ERROR : ResponseCode::NO_ERROR;
356    }
357    if (rc != ResponseCode::NO_ERROR) {
358        return rc;
359    }
360
361    auto& dev = getDevice(keyBlob);
362
363    if (keyBlob.getType() == ::TYPE_KEY_PAIR || keyBlob.getType() == ::TYPE_KEYMASTER_10) {
364        auto ret = KS_HANDLE_HIDL_ERROR(dev->deleteKey(blob2hidlVec(keyBlob)));
365
366        // A device doesn't have to implement delete_key.
367        if (ret != ErrorCode::OK && ret != ErrorCode::UNIMPLEMENTED)
368            return ResponseCode::SYSTEM_ERROR;
369    }
370
371    rc = (unlink(filename) && errno != ENOENT) ?
372            ResponseCode::SYSTEM_ERROR : ResponseCode::NO_ERROR;
373
374    if (rc == ResponseCode::NO_ERROR && keyBlob.getType() != ::TYPE_KEY_CHARACTERISTICS) {
375        // now that we have successfully deleted a key, let's make sure there are no stale grants
376        if (uidAlias.isOk()) {
377            mGrants.removeAllGrantsToKey(uid, alias);
378        }
379    }
380    return rc;
381}
382
383/*
384 * Converts from the "escaped" format on disk to actual name.
385 * This will be smaller than the input string.
386 *
387 * Characters that should combine with the next at the end will be truncated.
388 */
389static size_t decode_key_length(const char* in, size_t length) {
390    size_t outLength = 0;
391
392    for (const char* end = in + length; in < end; in++) {
393        /* This combines with the next character. */
394        if (*in < '0' || *in > '~') {
395            continue;
396        }
397
398        outLength++;
399    }
400    return outLength;
401}
402
403static void decode_key(char* out, const char* in, size_t length) {
404    for (const char* end = in + length; in < end; in++) {
405        if (*in < '0' || *in > '~') {
406            /* Truncate combining characters at the end. */
407            if (in + 1 >= end) {
408                break;
409            }
410
411            *out = (*in++ - '+') << 6;
412            *out++ |= (*in - '0') & 0x3F;
413        } else {
414            *out++ = *in;
415        }
416    }
417    *out = '\0';
418}
419
420static NullOr<std::tuple<uid_t, std::string>> filename2UidAlias(const std::string& filepath) {
421    auto filenamebase = filepath.find_last_of('/');
422    std::string filename = filenamebase == std::string::npos ? filepath :
423            filepath.substr(filenamebase + 1);
424
425    if (filename[0] == '.') return {};
426
427    auto sep = filename.find('_');
428    if (sep == std::string::npos) return {};
429
430    std::stringstream s(filename.substr(0, sep));
431    uid_t uid;
432    s >> uid;
433    if (!s) return {};
434
435    auto alias = filename.substr(sep + 1);
436
437    std::vector<char> alias_buffer(decode_key_length(alias.c_str(), alias.size()) + 1);
438
439    decode_key(alias_buffer.data(), alias.c_str(), alias.size());
440    return std::tuple<uid_t, std::string>(uid, alias_buffer.data());
441}
442
443ResponseCode KeyStore::list(const android::String8& prefix,
444                            android::Vector<android::String16>* matches, uid_t userId) {
445
446    UserState* userState = getUserState(userId);
447    size_t n = prefix.length();
448
449    DIR* dir = opendir(userState->getUserDirName());
450    if (!dir) {
451        ALOGW("can't open directory for user: %s", strerror(errno));
452        return ResponseCode::SYSTEM_ERROR;
453    }
454
455    struct dirent* file;
456    while ((file = readdir(dir)) != NULL) {
457        // We only care about files.
458        if (file->d_type != DT_REG) {
459            continue;
460        }
461
462        // Skip anything that starts with a "."
463        if (file->d_name[0] == '.') {
464            continue;
465        }
466
467        if (!strncmp(prefix.string(), file->d_name, n)) {
468            const char* p = &file->d_name[n];
469            size_t plen = strlen(p);
470
471            size_t extra = decode_key_length(p, plen);
472            char* match = (char*)malloc(extra + 1);
473            if (match != NULL) {
474                decode_key(match, p, plen);
475                matches->push(android::String16(match, extra));
476                free(match);
477            } else {
478                ALOGW("could not allocate match of size %zd", extra);
479            }
480        }
481    }
482    closedir(dir);
483    return ResponseCode::NO_ERROR;
484}
485
486std::string KeyStore::addGrant(const char* alias, uid_t granterUid, uid_t granteeUid) {
487    return mGrants.put(granteeUid, alias, getUserStateByUid(granterUid)->getUserDirName(),
488                       granterUid);
489}
490
491bool KeyStore::removeGrant(const char* alias, const uid_t granterUid, const uid_t granteeUid) {
492    return mGrants.removeByFileAlias(granteeUid, granterUid, alias);
493}
494void KeyStore::removeAllGrantsToUid(const uid_t granteeUid) {
495    mGrants.removeAllGrantsToUid(granteeUid);
496}
497
498ResponseCode KeyStore::importKey(const uint8_t* key, size_t keyLen, const char* filename,
499                                 uid_t userId, int32_t flags) {
500    Unique_PKCS8_PRIV_KEY_INFO pkcs8(d2i_PKCS8_PRIV_KEY_INFO(NULL, &key, keyLen));
501    if (!pkcs8.get()) {
502        return ResponseCode::SYSTEM_ERROR;
503    }
504    Unique_EVP_PKEY pkey(EVP_PKCS82PKEY(pkcs8.get()));
505    if (!pkey.get()) {
506        return ResponseCode::SYSTEM_ERROR;
507    }
508    int type = EVP_PKEY_type(pkey->type);
509    AuthorizationSet params;
510    add_legacy_key_authorizations(type, &params);
511    switch (type) {
512    case EVP_PKEY_RSA:
513        params.push_back(TAG_ALGORITHM, Algorithm::RSA);
514        break;
515    case EVP_PKEY_EC:
516        params.push_back(TAG_ALGORITHM, Algorithm::EC);
517        break;
518    default:
519        ALOGW("Unsupported key type %d", type);
520        return ResponseCode::SYSTEM_ERROR;
521    }
522
523    AuthorizationSet opParams(params);
524    hidl_vec<uint8_t> blob;
525
526    ErrorCode error;
527    auto hidlCb = [&] (ErrorCode ret, const hidl_vec<uint8_t>& keyBlob,
528            const KeyCharacteristics& /* ignored */) {
529        error = ret;
530        if (error != ErrorCode::OK) return;
531        blob = keyBlob;
532    };
533    auto input = blob2hidlVec(key, keyLen);
534
535    ErrorCode rc = KS_HANDLE_HIDL_ERROR(
536            mDevice->importKey(params.hidl_data(), KeyFormat::PKCS8, input, hidlCb));
537    if (rc != ErrorCode::OK) return ResponseCode::SYSTEM_ERROR;
538    if (error != ErrorCode::OK) {
539        ALOGE("Keymaster error %d importing key pair", error);
540        return ResponseCode::SYSTEM_ERROR;
541    }
542
543    Blob keyBlob(&blob[0], blob.size(), NULL, 0, TYPE_KEYMASTER_10);
544
545    keyBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
546    keyBlob.setFallback(false);
547
548    return put(filename, &keyBlob, userId);
549}
550
551bool KeyStore::isHardwareBacked(const android::String16& /*keyType*/) const {
552    using ::android::hardware::hidl_string;
553    if (mDevice == NULL) {
554        ALOGW("can't get keymaster device");
555        return false;
556    }
557
558    bool isSecure = false;
559    auto hidlcb = [&] (bool _isSecure, bool, bool, bool, bool, const hidl_string&,
560                       const hidl_string&) {
561        isSecure = _isSecure;
562    };
563    auto rc = mDevice->getHardwareFeatures(hidlcb);
564    if (!rc.isOk()) {
565        ALOGE("Communication with keymaster HAL failed while retrieving hardware features (%s)",
566                rc.description().c_str());
567        return false;
568    }
569    return isSecure;
570}
571
572ResponseCode KeyStore::getKeyForName(Blob* keyBlob, const android::String8& keyName,
573                                     const uid_t uid, const BlobType type) {
574    auto filepath8 = getBlobFileNameIfExists(keyName, uid, type);
575    uid_t userId = get_user_id(uid);
576
577    if (filepath8.isOk())
578        return get(filepath8.value().string(), keyBlob, type, userId);
579
580    return ResponseCode::KEY_NOT_FOUND;
581}
582
583UserState* KeyStore::getUserState(uid_t userId) {
584    for (android::Vector<UserState*>::iterator it(mMasterKeys.begin()); it != mMasterKeys.end();
585         it++) {
586        UserState* state = *it;
587        if (state->getUserId() == userId) {
588            return state;
589        }
590    }
591
592    UserState* userState = new UserState(userId);
593    if (!userState->initialize()) {
594        /* There's not much we can do if initialization fails. Trying to
595         * unlock the keystore for that user will fail as well, so any
596         * subsequent request for this user will just return SYSTEM_ERROR.
597         */
598        ALOGE("User initialization failed for %u; subsuquent operations will fail", userId);
599    }
600    mMasterKeys.add(userState);
601    return userState;
602}
603
604UserState* KeyStore::getUserStateByUid(uid_t uid) {
605    uid_t userId = get_user_id(uid);
606    return getUserState(userId);
607}
608
609const UserState* KeyStore::getUserState(uid_t userId) const {
610    for (android::Vector<UserState*>::const_iterator it(mMasterKeys.begin());
611         it != mMasterKeys.end(); it++) {
612        UserState* state = *it;
613        if (state->getUserId() == userId) {
614            return state;
615        }
616    }
617
618    return NULL;
619}
620
621const UserState* KeyStore::getUserStateByUid(uid_t uid) const {
622    uid_t userId = get_user_id(uid);
623    return getUserState(userId);
624}
625
626bool KeyStore::upgradeBlob(const char* filename, Blob* blob, const uint8_t oldVersion,
627                           const BlobType type, uid_t userId) {
628    bool updated = false;
629    uint8_t version = oldVersion;
630
631    /* From V0 -> V1: All old types were unknown */
632    if (version == 0) {
633        ALOGV("upgrading to version 1 and setting type %d", type);
634
635        blob->setType(type);
636        if (type == TYPE_KEY_PAIR) {
637            importBlobAsKey(blob, filename, userId);
638        }
639        version = 1;
640        updated = true;
641    }
642
643    /* From V1 -> V2: All old keys were encrypted */
644    if (version == 1) {
645        ALOGV("upgrading to version 2");
646
647        blob->setEncrypted(true);
648        version = 2;
649        updated = true;
650    }
651
652    /*
653     * If we've updated, set the key blob to the right version
654     * and write it.
655     */
656    if (updated) {
657        ALOGV("updated and writing file %s", filename);
658        blob->setVersion(version);
659    }
660
661    return updated;
662}
663
664struct BIO_Delete {
665    void operator()(BIO* p) const { BIO_free(p); }
666};
667typedef std::unique_ptr<BIO, BIO_Delete> Unique_BIO;
668
669ResponseCode KeyStore::importBlobAsKey(Blob* blob, const char* filename, uid_t userId) {
670    // We won't even write to the blob directly with this BIO, so const_cast is okay.
671    Unique_BIO b(BIO_new_mem_buf(const_cast<uint8_t*>(blob->getValue()), blob->getLength()));
672    if (b.get() == NULL) {
673        ALOGE("Problem instantiating BIO");
674        return ResponseCode::SYSTEM_ERROR;
675    }
676
677    Unique_EVP_PKEY pkey(PEM_read_bio_PrivateKey(b.get(), NULL, NULL, NULL));
678    if (pkey.get() == NULL) {
679        ALOGE("Couldn't read old PEM file");
680        return ResponseCode::SYSTEM_ERROR;
681    }
682
683    Unique_PKCS8_PRIV_KEY_INFO pkcs8(EVP_PKEY2PKCS8(pkey.get()));
684    int len = i2d_PKCS8_PRIV_KEY_INFO(pkcs8.get(), NULL);
685    if (len < 0) {
686        ALOGE("Couldn't measure PKCS#8 length");
687        return ResponseCode::SYSTEM_ERROR;
688    }
689
690    std::unique_ptr<unsigned char[]> pkcs8key(new unsigned char[len]);
691    uint8_t* tmp = pkcs8key.get();
692    if (i2d_PKCS8_PRIV_KEY_INFO(pkcs8.get(), &tmp) != len) {
693        ALOGE("Couldn't convert to PKCS#8");
694        return ResponseCode::SYSTEM_ERROR;
695    }
696
697    ResponseCode rc = importKey(pkcs8key.get(), len, filename, userId,
698                                blob->isEncrypted() ? KEYSTORE_FLAG_ENCRYPTED : KEYSTORE_FLAG_NONE);
699    if (rc != ResponseCode::NO_ERROR) {
700        return rc;
701    }
702
703    return get(filename, blob, TYPE_KEY_PAIR, userId);
704}
705
706void KeyStore::readMetaData() {
707    int in = TEMP_FAILURE_RETRY(open(sMetaDataFile, O_RDONLY));
708    if (in < 0) {
709        return;
710    }
711    size_t fileLength = readFully(in, (uint8_t*)&mMetaData, sizeof(mMetaData));
712    if (fileLength != sizeof(mMetaData)) {
713        ALOGI("Metadata file is %zd bytes (%zd experted); upgrade?", fileLength, sizeof(mMetaData));
714    }
715    close(in);
716}
717
718void KeyStore::writeMetaData() {
719    const char* tmpFileName = ".metadata.tmp";
720    int out =
721        TEMP_FAILURE_RETRY(open(tmpFileName, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR));
722    if (out < 0) {
723        ALOGE("couldn't write metadata file: %s", strerror(errno));
724        return;
725    }
726    size_t fileLength = writeFully(out, (uint8_t*)&mMetaData, sizeof(mMetaData));
727    if (fileLength != sizeof(mMetaData)) {
728        ALOGI("Could only write %zd bytes to metadata file (%zd expected)", fileLength,
729              sizeof(mMetaData));
730    }
731    close(out);
732    rename(tmpFileName, sMetaDataFile);
733}
734
735bool KeyStore::upgradeKeystore() {
736    bool upgraded = false;
737
738    if (mMetaData.version == 0) {
739        UserState* userState = getUserStateByUid(0);
740
741        // Initialize first so the directory is made.
742        userState->initialize();
743
744        // Migrate the old .masterkey file to user 0.
745        if (access(sOldMasterKey, R_OK) == 0) {
746            if (rename(sOldMasterKey, userState->getMasterKeyFileName()) < 0) {
747                ALOGE("couldn't migrate old masterkey: %s", strerror(errno));
748                return false;
749            }
750        }
751
752        // Initialize again in case we had a key.
753        userState->initialize();
754
755        // Try to migrate existing keys.
756        DIR* dir = opendir(".");
757        if (!dir) {
758            // Give up now; maybe we can upgrade later.
759            ALOGE("couldn't open keystore's directory; something is wrong");
760            return false;
761        }
762
763        struct dirent* file;
764        while ((file = readdir(dir)) != NULL) {
765            // We only care about files.
766            if (file->d_type != DT_REG) {
767                continue;
768            }
769
770            // Skip anything that starts with a "."
771            if (file->d_name[0] == '.') {
772                continue;
773            }
774
775            // Find the current file's user.
776            char* end;
777            unsigned long thisUid = strtoul(file->d_name, &end, 10);
778            if (end[0] != '_' || end[1] == 0) {
779                continue;
780            }
781            UserState* otherUser = getUserStateByUid(thisUid);
782            if (otherUser->getUserId() != 0) {
783                unlinkat(dirfd(dir), file->d_name, 0);
784            }
785
786            // Rename the file into user directory.
787            DIR* otherdir = opendir(otherUser->getUserDirName());
788            if (otherdir == NULL) {
789                ALOGW("couldn't open user directory for rename");
790                continue;
791            }
792            if (renameat(dirfd(dir), file->d_name, dirfd(otherdir), file->d_name) < 0) {
793                ALOGW("couldn't rename blob: %s: %s", file->d_name, strerror(errno));
794            }
795            closedir(otherdir);
796        }
797        closedir(dir);
798
799        mMetaData.version = 1;
800        upgraded = true;
801    }
802
803    return upgraded;
804}
805