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      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 #include "keystore.h"
     18 
     19 #include <dirent.h>
     20 #include <fcntl.h>
     21 
     22 #include <openssl/bio.h>
     23 
     24 #include <utils/String16.h>
     25 
     26 #include <keystore/IKeystoreService.h>
     27 
     28 #include "keystore_utils.h"
     29 #include "permissions.h"
     30 
     31 const char* KeyStore::sOldMasterKey = ".masterkey";
     32 const char* KeyStore::sMetaDataFile = ".metadata";
     33 
     34 const android::String16 KeyStore::sRSAKeyType("RSA");
     35 
     36 KeyStore::KeyStore(Entropy* entropy, keymaster2_device_t* device, keymaster2_device_t* fallback)
     37     : mEntropy(entropy), mDevice(device), mFallbackDevice(fallback) {
     38     memset(&mMetaData, '\0', sizeof(mMetaData));
     39 }
     40 
     41 KeyStore::~KeyStore() {
     42     for (android::Vector<grant_t*>::iterator it(mGrants.begin()); it != mGrants.end(); it++) {
     43         delete *it;
     44     }
     45     mGrants.clear();
     46 
     47     for (android::Vector<UserState*>::iterator it(mMasterKeys.begin()); it != mMasterKeys.end();
     48          it++) {
     49         delete *it;
     50     }
     51     mMasterKeys.clear();
     52 }
     53 
     54 ResponseCode KeyStore::initialize() {
     55     readMetaData();
     56     if (upgradeKeystore()) {
     57         writeMetaData();
     58     }
     59 
     60     return ::NO_ERROR;
     61 }
     62 
     63 ResponseCode KeyStore::initializeUser(const android::String8& pw, uid_t userId) {
     64     UserState* userState = getUserState(userId);
     65     return userState->initialize(pw, mEntropy);
     66 }
     67 
     68 ResponseCode KeyStore::copyMasterKey(uid_t srcUser, uid_t dstUser) {
     69     UserState* userState = getUserState(dstUser);
     70     UserState* initState = getUserState(srcUser);
     71     return userState->copyMasterKey(initState);
     72 }
     73 
     74 ResponseCode KeyStore::writeMasterKey(const android::String8& pw, uid_t userId) {
     75     UserState* userState = getUserState(userId);
     76     return userState->writeMasterKey(pw, mEntropy);
     77 }
     78 
     79 ResponseCode KeyStore::readMasterKey(const android::String8& pw, uid_t userId) {
     80     UserState* userState = getUserState(userId);
     81     return userState->readMasterKey(pw, mEntropy);
     82 }
     83 
     84 /* Here is the encoding of keys. This is necessary in order to allow arbitrary
     85  * characters in keys. Characters in [0-~] are not encoded. Others are encoded
     86  * into two bytes. The first byte is one of [+-.] which represents the first
     87  * two bits of the character. The second byte encodes the rest of the bits into
     88  * [0-o]. Therefore in the worst case the length of a key gets doubled. Note
     89  * that Base64 cannot be used here due to the need of prefix match on keys. */
     90 
     91 static size_t encode_key_length(const android::String8& keyName) {
     92     const uint8_t* in = reinterpret_cast<const uint8_t*>(keyName.string());
     93     size_t length = keyName.length();
     94     for (int i = length; i > 0; --i, ++in) {
     95         if (*in < '0' || *in > '~') {
     96             ++length;
     97         }
     98     }
     99     return length;
    100 }
    101 
    102 static int encode_key(char* out, const android::String8& keyName) {
    103     const uint8_t* in = reinterpret_cast<const uint8_t*>(keyName.string());
    104     size_t length = keyName.length();
    105     for (int i = length; i > 0; --i, ++in, ++out) {
    106         if (*in < '0' || *in > '~') {
    107             *out = '+' + (*in >> 6);
    108             *++out = '0' + (*in & 0x3F);
    109             ++length;
    110         } else {
    111             *out = *in;
    112         }
    113     }
    114     *out = '\0';
    115     return length;
    116 }
    117 
    118 android::String8 KeyStore::getKeyName(const android::String8& keyName) {
    119     char encoded[encode_key_length(keyName) + 1];  // add 1 for null char
    120     encode_key(encoded, keyName);
    121     return android::String8(encoded);
    122 }
    123 
    124 android::String8 KeyStore::getKeyNameForUid(const android::String8& keyName, uid_t uid) {
    125     char encoded[encode_key_length(keyName) + 1];  // add 1 for null char
    126     encode_key(encoded, keyName);
    127     return android::String8::format("%u_%s", uid, encoded);
    128 }
    129 
    130 android::String8 KeyStore::getKeyNameForUidWithDir(const android::String8& keyName, uid_t uid) {
    131     char encoded[encode_key_length(keyName) + 1];  // add 1 for null char
    132     encode_key(encoded, keyName);
    133     return android::String8::format("%s/%u_%s", getUserStateByUid(uid)->getUserDirName(), uid,
    134                                     encoded);
    135 }
    136 
    137 void KeyStore::resetUser(uid_t userId, bool keepUnenryptedEntries) {
    138     android::String8 prefix("");
    139     android::Vector<android::String16> aliases;
    140     UserState* userState = getUserState(userId);
    141     if (list(prefix, &aliases, userId) != ::NO_ERROR) {
    142         return;
    143     }
    144     for (uint32_t i = 0; i < aliases.size(); i++) {
    145         android::String8 filename(aliases[i]);
    146         filename = android::String8::format("%s/%s", userState->getUserDirName(),
    147                                             getKeyName(filename).string());
    148         bool shouldDelete = true;
    149         if (keepUnenryptedEntries) {
    150             Blob blob;
    151             ResponseCode rc = get(filename, &blob, ::TYPE_ANY, userId);
    152 
    153             /* get can fail if the blob is encrypted and the state is
    154              * not unlocked, only skip deleting blobs that were loaded and
    155              * who are not encrypted. If there are blobs we fail to read for
    156              * other reasons err on the safe side and delete them since we
    157              * can't tell if they're encrypted.
    158              */
    159             shouldDelete = !(rc == ::NO_ERROR && !blob.isEncrypted());
    160         }
    161         if (shouldDelete) {
    162             del(filename, ::TYPE_ANY, userId);
    163         }
    164     }
    165     if (!userState->deleteMasterKey()) {
    166         ALOGE("Failed to delete user %d's master key", userId);
    167     }
    168     if (!keepUnenryptedEntries) {
    169         if (!userState->reset()) {
    170             ALOGE("Failed to remove user %d's directory", userId);
    171         }
    172     }
    173 }
    174 
    175 bool KeyStore::isEmpty(uid_t userId) const {
    176     const UserState* userState = getUserState(userId);
    177     if (userState == NULL) {
    178         return true;
    179     }
    180 
    181     DIR* dir = opendir(userState->getUserDirName());
    182     if (!dir) {
    183         return true;
    184     }
    185 
    186     bool result = true;
    187     struct dirent* file;
    188     while ((file = readdir(dir)) != NULL) {
    189         // We only care about files.
    190         if (file->d_type != DT_REG) {
    191             continue;
    192         }
    193 
    194         // Skip anything that starts with a "."
    195         if (file->d_name[0] == '.') {
    196             continue;
    197         }
    198 
    199         result = false;
    200         break;
    201     }
    202     closedir(dir);
    203     return result;
    204 }
    205 
    206 void KeyStore::lock(uid_t userId) {
    207     UserState* userState = getUserState(userId);
    208     userState->zeroizeMasterKeysInMemory();
    209     userState->setState(STATE_LOCKED);
    210 }
    211 
    212 ResponseCode KeyStore::get(const char* filename, Blob* keyBlob, const BlobType type, uid_t userId) {
    213     UserState* userState = getUserState(userId);
    214     ResponseCode rc =
    215         keyBlob->readBlob(filename, userState->getDecryptionKey(), userState->getState());
    216     if (rc != NO_ERROR) {
    217         return rc;
    218     }
    219 
    220     const uint8_t version = keyBlob->getVersion();
    221     if (version < CURRENT_BLOB_VERSION) {
    222         /* If we upgrade the key, we need to write it to disk again. Then
    223          * it must be read it again since the blob is encrypted each time
    224          * it's written.
    225          */
    226         if (upgradeBlob(filename, keyBlob, version, type, userId)) {
    227             if ((rc = this->put(filename, keyBlob, userId)) != NO_ERROR ||
    228                 (rc = keyBlob->readBlob(filename, userState->getDecryptionKey(),
    229                                         userState->getState())) != NO_ERROR) {
    230                 return rc;
    231             }
    232         }
    233     }
    234 
    235     /*
    236      * This will upgrade software-backed keys to hardware-backed keys when
    237      * the HAL for the device supports the newer key types.
    238      */
    239     if (rc == NO_ERROR && type == TYPE_KEY_PAIR &&
    240         mDevice->common.module->module_api_version >= KEYMASTER_MODULE_API_VERSION_0_2 &&
    241         keyBlob->isFallback()) {
    242         ResponseCode imported =
    243             importKey(keyBlob->getValue(), keyBlob->getLength(), filename, userId,
    244                       keyBlob->isEncrypted() ? KEYSTORE_FLAG_ENCRYPTED : KEYSTORE_FLAG_NONE);
    245 
    246         // The HAL allowed the import, reget the key to have the "fresh"
    247         // version.
    248         if (imported == NO_ERROR) {
    249             rc = get(filename, keyBlob, TYPE_KEY_PAIR, userId);
    250         }
    251     }
    252 
    253     // Keymaster 0.3 keys are valid keymaster 1.0 keys, so silently upgrade.
    254     if (keyBlob->getType() == TYPE_KEY_PAIR) {
    255         keyBlob->setType(TYPE_KEYMASTER_10);
    256         rc = this->put(filename, keyBlob, userId);
    257     }
    258 
    259     if (type != TYPE_ANY && keyBlob->getType() != type) {
    260         ALOGW("key found but type doesn't match: %d vs %d", keyBlob->getType(), type);
    261         return KEY_NOT_FOUND;
    262     }
    263 
    264     return rc;
    265 }
    266 
    267 ResponseCode KeyStore::put(const char* filename, Blob* keyBlob, uid_t userId) {
    268     UserState* userState = getUserState(userId);
    269     return keyBlob->writeBlob(filename, userState->getEncryptionKey(), userState->getState(),
    270                               mEntropy);
    271 }
    272 
    273 ResponseCode KeyStore::del(const char* filename, const BlobType type, uid_t userId) {
    274     Blob keyBlob;
    275     ResponseCode rc = get(filename, &keyBlob, type, userId);
    276     if (rc == ::VALUE_CORRUPTED) {
    277         // The file is corrupt, the best we can do is rm it.
    278         return (unlink(filename) && errno != ENOENT) ? ::SYSTEM_ERROR : ::NO_ERROR;
    279     }
    280     if (rc != ::NO_ERROR) {
    281         return rc;
    282     }
    283 
    284     if (keyBlob.getType() == ::TYPE_KEY_PAIR) {
    285         // A device doesn't have to implement delete_key.
    286         if (mDevice->delete_key != NULL && !keyBlob.isFallback()) {
    287             keymaster_key_blob_t blob = {keyBlob.getValue(),
    288                                          static_cast<size_t>(keyBlob.getLength())};
    289             if (mDevice->delete_key(mDevice, &blob)) {
    290                 rc = ::SYSTEM_ERROR;
    291             }
    292         }
    293     }
    294     if (keyBlob.getType() == ::TYPE_KEYMASTER_10) {
    295         auto* dev = getDeviceForBlob(keyBlob);
    296         if (dev->delete_key) {
    297             keymaster_key_blob_t blob;
    298             blob.key_material = keyBlob.getValue();
    299             blob.key_material_size = keyBlob.getLength();
    300             dev->delete_key(dev, &blob);
    301         }
    302     }
    303     if (rc != ::NO_ERROR) {
    304         return rc;
    305     }
    306 
    307     return (unlink(filename) && errno != ENOENT) ? ::SYSTEM_ERROR : ::NO_ERROR;
    308 }
    309 
    310 /*
    311  * Converts from the "escaped" format on disk to actual name.
    312  * This will be smaller than the input string.
    313  *
    314  * Characters that should combine with the next at the end will be truncated.
    315  */
    316 static size_t decode_key_length(const char* in, size_t length) {
    317     size_t outLength = 0;
    318 
    319     for (const char* end = in + length; in < end; in++) {
    320         /* This combines with the next character. */
    321         if (*in < '0' || *in > '~') {
    322             continue;
    323         }
    324 
    325         outLength++;
    326     }
    327     return outLength;
    328 }
    329 
    330 static void decode_key(char* out, const char* in, size_t length) {
    331     for (const char* end = in + length; in < end; in++) {
    332         if (*in < '0' || *in > '~') {
    333             /* Truncate combining characters at the end. */
    334             if (in + 1 >= end) {
    335                 break;
    336             }
    337 
    338             *out = (*in++ - '+') << 6;
    339             *out++ |= (*in - '0') & 0x3F;
    340         } else {
    341             *out++ = *in;
    342         }
    343     }
    344     *out = '\0';
    345 }
    346 
    347 ResponseCode KeyStore::list(const android::String8& prefix,
    348                             android::Vector<android::String16>* matches, uid_t userId) {
    349 
    350     UserState* userState = getUserState(userId);
    351     size_t n = prefix.length();
    352 
    353     DIR* dir = opendir(userState->getUserDirName());
    354     if (!dir) {
    355         ALOGW("can't open directory for user: %s", strerror(errno));
    356         return ::SYSTEM_ERROR;
    357     }
    358 
    359     struct dirent* file;
    360     while ((file = readdir(dir)) != NULL) {
    361         // We only care about files.
    362         if (file->d_type != DT_REG) {
    363             continue;
    364         }
    365 
    366         // Skip anything that starts with a "."
    367         if (file->d_name[0] == '.') {
    368             continue;
    369         }
    370 
    371         if (!strncmp(prefix.string(), file->d_name, n)) {
    372             const char* p = &file->d_name[n];
    373             size_t plen = strlen(p);
    374 
    375             size_t extra = decode_key_length(p, plen);
    376             char* match = (char*)malloc(extra + 1);
    377             if (match != NULL) {
    378                 decode_key(match, p, plen);
    379                 matches->push(android::String16(match, extra));
    380                 free(match);
    381             } else {
    382                 ALOGW("could not allocate match of size %zd", extra);
    383             }
    384         }
    385     }
    386     closedir(dir);
    387     return ::NO_ERROR;
    388 }
    389 
    390 void KeyStore::addGrant(const char* filename, uid_t granteeUid) {
    391     const grant_t* existing = getGrant(filename, granteeUid);
    392     if (existing == NULL) {
    393         grant_t* grant = new grant_t;
    394         grant->uid = granteeUid;
    395         grant->filename = reinterpret_cast<const uint8_t*>(strdup(filename));
    396         mGrants.add(grant);
    397     }
    398 }
    399 
    400 bool KeyStore::removeGrant(const char* filename, uid_t granteeUid) {
    401     for (android::Vector<grant_t*>::iterator it(mGrants.begin()); it != mGrants.end(); it++) {
    402         grant_t* grant = *it;
    403         if (grant->uid == granteeUid &&
    404             !strcmp(reinterpret_cast<const char*>(grant->filename), filename)) {
    405             mGrants.erase(it);
    406             return true;
    407         }
    408     }
    409     return false;
    410 }
    411 
    412 ResponseCode KeyStore::importKey(const uint8_t* key, size_t keyLen, const char* filename,
    413                                  uid_t userId, int32_t flags) {
    414     Unique_PKCS8_PRIV_KEY_INFO pkcs8(d2i_PKCS8_PRIV_KEY_INFO(NULL, &key, keyLen));
    415     if (!pkcs8.get()) {
    416         return ::SYSTEM_ERROR;
    417     }
    418     Unique_EVP_PKEY pkey(EVP_PKCS82PKEY(pkcs8.get()));
    419     if (!pkey.get()) {
    420         return ::SYSTEM_ERROR;
    421     }
    422     int type = EVP_PKEY_type(pkey->type);
    423     android::KeymasterArguments params;
    424     add_legacy_key_authorizations(type, &params.params);
    425     switch (type) {
    426     case EVP_PKEY_RSA:
    427         params.params.push_back(keymaster_param_enum(KM_TAG_ALGORITHM, KM_ALGORITHM_RSA));
    428         break;
    429     case EVP_PKEY_EC:
    430         params.params.push_back(keymaster_param_enum(KM_TAG_ALGORITHM, KM_ALGORITHM_EC));
    431         break;
    432     default:
    433         ALOGW("Unsupported key type %d", type);
    434         return ::SYSTEM_ERROR;
    435     }
    436 
    437     std::vector<keymaster_key_param_t> opParams(params.params);
    438     const keymaster_key_param_set_t inParams = {opParams.data(), opParams.size()};
    439     keymaster_blob_t input = {key, keyLen};
    440     keymaster_key_blob_t blob = {nullptr, 0};
    441     bool isFallback = false;
    442     keymaster_error_t error = mDevice->import_key(mDevice, &inParams, KM_KEY_FORMAT_PKCS8, &input,
    443                                                   &blob, NULL /* characteristics */);
    444     if (error != KM_ERROR_OK) {
    445         ALOGE("Keymaster error %d importing key pair, falling back", error);
    446 
    447         /*
    448          * There should be no way to get here.  Fallback shouldn't ever really happen
    449          * because the main device may be many (SW, KM0/SW hybrid, KM1/SW hybrid), but it must
    450          * provide full support of the API.  In any case, we'll do the fallback just for
    451          * consistency... and I suppose to cover for broken HW implementations.
    452          */
    453         error = mFallbackDevice->import_key(mFallbackDevice, &inParams, KM_KEY_FORMAT_PKCS8, &input,
    454                                             &blob, NULL /* characteristics */);
    455         isFallback = true;
    456 
    457         if (error) {
    458             ALOGE("Keymaster error while importing key pair with fallback: %d", error);
    459             return SYSTEM_ERROR;
    460         }
    461     }
    462 
    463     Blob keyBlob(blob.key_material, blob.key_material_size, NULL, 0, TYPE_KEYMASTER_10);
    464     free(const_cast<uint8_t*>(blob.key_material));
    465 
    466     keyBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
    467     keyBlob.setFallback(isFallback);
    468 
    469     return put(filename, &keyBlob, userId);
    470 }
    471 
    472 bool KeyStore::isHardwareBacked(const android::String16& keyType) const {
    473     if (mDevice == NULL) {
    474         ALOGW("can't get keymaster device");
    475         return false;
    476     }
    477 
    478     if (sRSAKeyType == keyType) {
    479         return (mDevice->flags & KEYMASTER_SOFTWARE_ONLY) == 0;
    480     } else {
    481         return (mDevice->flags & KEYMASTER_SOFTWARE_ONLY) == 0 &&
    482                (mDevice->common.module->module_api_version >= KEYMASTER_MODULE_API_VERSION_0_2);
    483     }
    484 }
    485 
    486 ResponseCode KeyStore::getKeyForName(Blob* keyBlob, const android::String8& keyName,
    487                                      const uid_t uid, const BlobType type) {
    488     android::String8 filepath8(getKeyNameForUidWithDir(keyName, uid));
    489     uid_t userId = get_user_id(uid);
    490 
    491     ResponseCode responseCode = get(filepath8.string(), keyBlob, type, userId);
    492     if (responseCode == NO_ERROR) {
    493         return responseCode;
    494     }
    495 
    496     // If this is one of the legacy UID->UID mappings, use it.
    497     uid_t euid = get_keystore_euid(uid);
    498     if (euid != uid) {
    499         filepath8 = getKeyNameForUidWithDir(keyName, euid);
    500         responseCode = get(filepath8.string(), keyBlob, type, userId);
    501         if (responseCode == NO_ERROR) {
    502             return responseCode;
    503         }
    504     }
    505 
    506     // They might be using a granted key.
    507     android::String8 filename8 = getKeyName(keyName);
    508     char* end;
    509     strtoul(filename8.string(), &end, 10);
    510     if (end[0] != '_' || end[1] == 0) {
    511         return KEY_NOT_FOUND;
    512     }
    513     filepath8 = android::String8::format("%s/%s", getUserState(userId)->getUserDirName(),
    514                                          filename8.string());
    515     if (!hasGrant(filepath8.string(), uid)) {
    516         return responseCode;
    517     }
    518 
    519     // It is a granted key. Try to load it.
    520     return get(filepath8.string(), keyBlob, type, userId);
    521 }
    522 
    523 UserState* KeyStore::getUserState(uid_t userId) {
    524     for (android::Vector<UserState*>::iterator it(mMasterKeys.begin()); it != mMasterKeys.end();
    525          it++) {
    526         UserState* state = *it;
    527         if (state->getUserId() == userId) {
    528             return state;
    529         }
    530     }
    531 
    532     UserState* userState = new UserState(userId);
    533     if (!userState->initialize()) {
    534         /* There's not much we can do if initialization fails. Trying to
    535          * unlock the keystore for that user will fail as well, so any
    536          * subsequent request for this user will just return SYSTEM_ERROR.
    537          */
    538         ALOGE("User initialization failed for %u; subsuquent operations will fail", userId);
    539     }
    540     mMasterKeys.add(userState);
    541     return userState;
    542 }
    543 
    544 UserState* KeyStore::getUserStateByUid(uid_t uid) {
    545     uid_t userId = get_user_id(uid);
    546     return getUserState(userId);
    547 }
    548 
    549 const UserState* KeyStore::getUserState(uid_t userId) const {
    550     for (android::Vector<UserState*>::const_iterator it(mMasterKeys.begin());
    551          it != mMasterKeys.end(); it++) {
    552         UserState* state = *it;
    553         if (state->getUserId() == userId) {
    554             return state;
    555         }
    556     }
    557 
    558     return NULL;
    559 }
    560 
    561 const UserState* KeyStore::getUserStateByUid(uid_t uid) const {
    562     uid_t userId = get_user_id(uid);
    563     return getUserState(userId);
    564 }
    565 
    566 const grant_t* KeyStore::getGrant(const char* filename, uid_t uid) const {
    567     for (android::Vector<grant_t*>::const_iterator it(mGrants.begin()); it != mGrants.end(); it++) {
    568         grant_t* grant = *it;
    569         if (grant->uid == uid &&
    570             !strcmp(reinterpret_cast<const char*>(grant->filename), filename)) {
    571             return grant;
    572         }
    573     }
    574     return NULL;
    575 }
    576 
    577 bool KeyStore::upgradeBlob(const char* filename, Blob* blob, const uint8_t oldVersion,
    578                            const BlobType type, uid_t uid) {
    579     bool updated = false;
    580     uint8_t version = oldVersion;
    581 
    582     /* From V0 -> V1: All old types were unknown */
    583     if (version == 0) {
    584         ALOGV("upgrading to version 1 and setting type %d", type);
    585 
    586         blob->setType(type);
    587         if (type == TYPE_KEY_PAIR) {
    588             importBlobAsKey(blob, filename, uid);
    589         }
    590         version = 1;
    591         updated = true;
    592     }
    593 
    594     /* From V1 -> V2: All old keys were encrypted */
    595     if (version == 1) {
    596         ALOGV("upgrading to version 2");
    597 
    598         blob->setEncrypted(true);
    599         version = 2;
    600         updated = true;
    601     }
    602 
    603     /*
    604      * If we've updated, set the key blob to the right version
    605      * and write it.
    606      */
    607     if (updated) {
    608         ALOGV("updated and writing file %s", filename);
    609         blob->setVersion(version);
    610     }
    611 
    612     return updated;
    613 }
    614 
    615 struct BIO_Delete {
    616     void operator()(BIO* p) const { BIO_free(p); }
    617 };
    618 typedef UniquePtr<BIO, BIO_Delete> Unique_BIO;
    619 
    620 ResponseCode KeyStore::importBlobAsKey(Blob* blob, const char* filename, uid_t uid) {
    621     // We won't even write to the blob directly with this BIO, so const_cast is okay.
    622     Unique_BIO b(BIO_new_mem_buf(const_cast<uint8_t*>(blob->getValue()), blob->getLength()));
    623     if (b.get() == NULL) {
    624         ALOGE("Problem instantiating BIO");
    625         return SYSTEM_ERROR;
    626     }
    627 
    628     Unique_EVP_PKEY pkey(PEM_read_bio_PrivateKey(b.get(), NULL, NULL, NULL));
    629     if (pkey.get() == NULL) {
    630         ALOGE("Couldn't read old PEM file");
    631         return SYSTEM_ERROR;
    632     }
    633 
    634     Unique_PKCS8_PRIV_KEY_INFO pkcs8(EVP_PKEY2PKCS8(pkey.get()));
    635     int len = i2d_PKCS8_PRIV_KEY_INFO(pkcs8.get(), NULL);
    636     if (len < 0) {
    637         ALOGE("Couldn't measure PKCS#8 length");
    638         return SYSTEM_ERROR;
    639     }
    640 
    641     UniquePtr<unsigned char[]> pkcs8key(new unsigned char[len]);
    642     uint8_t* tmp = pkcs8key.get();
    643     if (i2d_PKCS8_PRIV_KEY_INFO(pkcs8.get(), &tmp) != len) {
    644         ALOGE("Couldn't convert to PKCS#8");
    645         return SYSTEM_ERROR;
    646     }
    647 
    648     ResponseCode rc = importKey(pkcs8key.get(), len, filename, get_user_id(uid),
    649                                 blob->isEncrypted() ? KEYSTORE_FLAG_ENCRYPTED : KEYSTORE_FLAG_NONE);
    650     if (rc != NO_ERROR) {
    651         return rc;
    652     }
    653 
    654     return get(filename, blob, TYPE_KEY_PAIR, uid);
    655 }
    656 
    657 void KeyStore::readMetaData() {
    658     int in = TEMP_FAILURE_RETRY(open(sMetaDataFile, O_RDONLY));
    659     if (in < 0) {
    660         return;
    661     }
    662     size_t fileLength = readFully(in, (uint8_t*)&mMetaData, sizeof(mMetaData));
    663     if (fileLength != sizeof(mMetaData)) {
    664         ALOGI("Metadata file is %zd bytes (%zd experted); upgrade?", fileLength, sizeof(mMetaData));
    665     }
    666     close(in);
    667 }
    668 
    669 void KeyStore::writeMetaData() {
    670     const char* tmpFileName = ".metadata.tmp";
    671     int out =
    672         TEMP_FAILURE_RETRY(open(tmpFileName, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR));
    673     if (out < 0) {
    674         ALOGE("couldn't write metadata file: %s", strerror(errno));
    675         return;
    676     }
    677     size_t fileLength = writeFully(out, (uint8_t*)&mMetaData, sizeof(mMetaData));
    678     if (fileLength != sizeof(mMetaData)) {
    679         ALOGI("Could only write %zd bytes to metadata file (%zd expected)", fileLength,
    680               sizeof(mMetaData));
    681     }
    682     close(out);
    683     rename(tmpFileName, sMetaDataFile);
    684 }
    685 
    686 bool KeyStore::upgradeKeystore() {
    687     bool upgraded = false;
    688 
    689     if (mMetaData.version == 0) {
    690         UserState* userState = getUserStateByUid(0);
    691 
    692         // Initialize first so the directory is made.
    693         userState->initialize();
    694 
    695         // Migrate the old .masterkey file to user 0.
    696         if (access(sOldMasterKey, R_OK) == 0) {
    697             if (rename(sOldMasterKey, userState->getMasterKeyFileName()) < 0) {
    698                 ALOGE("couldn't migrate old masterkey: %s", strerror(errno));
    699                 return false;
    700             }
    701         }
    702 
    703         // Initialize again in case we had a key.
    704         userState->initialize();
    705 
    706         // Try to migrate existing keys.
    707         DIR* dir = opendir(".");
    708         if (!dir) {
    709             // Give up now; maybe we can upgrade later.
    710             ALOGE("couldn't open keystore's directory; something is wrong");
    711             return false;
    712         }
    713 
    714         struct dirent* file;
    715         while ((file = readdir(dir)) != NULL) {
    716             // We only care about files.
    717             if (file->d_type != DT_REG) {
    718                 continue;
    719             }
    720 
    721             // Skip anything that starts with a "."
    722             if (file->d_name[0] == '.') {
    723                 continue;
    724             }
    725 
    726             // Find the current file's user.
    727             char* end;
    728             unsigned long thisUid = strtoul(file->d_name, &end, 10);
    729             if (end[0] != '_' || end[1] == 0) {
    730                 continue;
    731             }
    732             UserState* otherUser = getUserStateByUid(thisUid);
    733             if (otherUser->getUserId() != 0) {
    734                 unlinkat(dirfd(dir), file->d_name, 0);
    735             }
    736 
    737             // Rename the file into user directory.
    738             DIR* otherdir = opendir(otherUser->getUserDirName());
    739             if (otherdir == NULL) {
    740                 ALOGW("couldn't open user directory for rename");
    741                 continue;
    742             }
    743             if (renameat(dirfd(dir), file->d_name, dirfd(otherdir), file->d_name) < 0) {
    744                 ALOGW("couldn't rename blob: %s: %s", file->d_name, strerror(errno));
    745             }
    746             closedir(otherdir);
    747         }
    748         closedir(dir);
    749 
    750         mMetaData.version = 1;
    751         upgraded = true;
    752     }
    753 
    754     return upgraded;
    755 }
    756