Snap for 4510491 from 0efbf432c1bc5bf52f93c73f8c9ba7476ce4bca7 to pi-release

Change-Id: I0fe811edf05f9ec775bf95ae1102b91a095927b4

1 files changed, 800 insertions, 0 deletions

diff --git a/keystore/KeyStore.cpp b/keystore/KeyStore.cpp
new file mode 100644
index 0000000..6952b54
--- /dev/null
+++ b/keystore/KeyStore.cpp
@@ -0,0 +1,800 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define LOG_TAG "keystore"
+
+#include "KeyStore.h"
+
+#include <dirent.h>
+#include <fcntl.h>
+
+#include <openssl/bio.h>
+
+#include <utils/String16.h>
+#include <utils/String8.h>
+
+#include <android/hardware/keymaster/3.0/IKeymasterDevice.h>
+#include <android/security/IKeystoreService.h>
+
+#include "keystore_utils.h"
+#include "permissions.h"
+#include <keystore/keystore_hidl_support.h>
+
+const char* KeyStore::sOldMasterKey = ".masterkey";
+const char* KeyStore::sMetaDataFile = ".metadata";
+
+const android::String16 KeyStore::sRSAKeyType("RSA");
+
+using namespace keystore;
+using android::String8;
+
+KeyStore::KeyStore(Entropy* entropy, const km_device_t& device, const km_device_t& fallback,
+                   bool allowNewFallback)
+    : mEntropy(entropy), mDevice(device), mFallbackDevice(fallback),
+      mAllowNewFallback(allowNewFallback) {
+    memset(&mMetaData, '\0', sizeof(mMetaData));
+}
+
+KeyStore::~KeyStore() {
+    for (android::Vector<UserState*>::iterator it(mMasterKeys.begin()); it != mMasterKeys.end();
+         it++) {
+        delete *it;
+    }
+    mMasterKeys.clear();
+}
+
+ResponseCode KeyStore::initialize() {
+    readMetaData();
+    if (upgradeKeystore()) {
+        writeMetaData();
+    }
+
+    return ResponseCode::NO_ERROR;
+}
+
+ResponseCode KeyStore::initializeUser(const android::String8& pw, uid_t userId) {
+    UserState* userState = getUserState(userId);
+    return userState->initialize(pw, mEntropy);
+}
+
+ResponseCode KeyStore::copyMasterKey(uid_t srcUser, uid_t dstUser) {
+    UserState* userState = getUserState(dstUser);
+    UserState* initState = getUserState(srcUser);
+    return userState->copyMasterKey(initState);
+}
+
+ResponseCode KeyStore::writeMasterKey(const android::String8& pw, uid_t userId) {
+    UserState* userState = getUserState(userId);
+    return userState->writeMasterKey(pw, mEntropy);
+}
+
+ResponseCode KeyStore::readMasterKey(const android::String8& pw, uid_t userId) {
+    UserState* userState = getUserState(userId);
+    return userState->readMasterKey(pw, mEntropy);
+}
+
+/* Here is the encoding of keys. This is necessary in order to allow arbitrary
+ * characters in keys. Characters in [0-~] are not encoded. Others are encoded
+ * into two bytes. The first byte is one of [+-.] which represents the first
+ * two bits of the character. The second byte encodes the rest of the bits into
+ * [0-o]. Therefore in the worst case the length of a key gets doubled. Note
+ * that Base64 cannot be used here due to the need of prefix match on keys. */
+
+static size_t encode_key_length(const android::String8& keyName) {
+    const uint8_t* in = reinterpret_cast<const uint8_t*>(keyName.string());
+    size_t length = keyName.length();
+    for (int i = length; i > 0; --i, ++in) {
+        if (*in < '0' || *in > '~') {
+            ++length;
+        }
+    }
+    return length;
+}
+
+static int encode_key(char* out, const android::String8& keyName) {
+    const uint8_t* in = reinterpret_cast<const uint8_t*>(keyName.string());
+    size_t length = keyName.length();
+    for (int i = length; i > 0; --i, ++in, ++out) {
+        if (*in < '0' || *in > '~') {
+            *out = '+' + (*in >> 6);
+            *++out = '0' + (*in & 0x3F);
+            ++length;
+        } else {
+            *out = *in;
+        }
+    }
+    *out = '\0';
+    return length;
+}
+
+android::String8 KeyStore::getKeyName(const android::String8& keyName, const BlobType type) {
+    std::vector<char> encoded(encode_key_length(keyName) + 1);  // add 1 for null char
+    encode_key(encoded.data(), keyName);
+    if (type == TYPE_KEY_CHARACTERISTICS) {
+        return android::String8::format(".chr_%s", encoded.data());
+    } else {
+        return android::String8(encoded.data());
+    }
+}
+
+android::String8 KeyStore::getKeyNameForUid(const android::String8& keyName, uid_t uid,
+                                            const BlobType type) {
+    std::vector<char> encoded(encode_key_length(keyName) + 1);  // add 1 for null char
+    encode_key(encoded.data(), keyName);
+    if (type == TYPE_KEY_CHARACTERISTICS) {
+        return android::String8::format(".%u_chr_%s", uid, encoded.data());
+    } else {
+        return android::String8::format("%u_%s", uid, encoded.data());
+    }
+}
+
+android::String8 KeyStore::getKeyNameForUidWithDir(const android::String8& keyName, uid_t uid,
+                                                   const BlobType type) {
+    std::vector<char> encoded(encode_key_length(keyName) + 1);  // add 1 for null char
+    encode_key(encoded.data(), keyName);
+
+    if (type == TYPE_KEY_CHARACTERISTICS) {
+        return android::String8::format("%s/.%u_chr_%s", getUserStateByUid(uid)->getUserDirName(),
+                                        uid, encoded.data());
+    } else {
+        return android::String8::format("%s/%u_%s", getUserStateByUid(uid)->getUserDirName(), uid,
+                                        encoded.data());
+    }
+}
+
+NullOr<android::String8> KeyStore::getBlobFileNameIfExists(const android::String8& alias, uid_t uid,
+                                                           const BlobType type) {
+    android::String8 filepath8(getKeyNameForUidWithDir(alias, uid, type));
+
+    if (!access(filepath8.string(), R_OK | W_OK)) return filepath8;
+
+    // If this is one of the legacy UID->UID mappings, use it.
+    uid_t euid = get_keystore_euid(uid);
+    if (euid != uid) {
+        filepath8 = getKeyNameForUidWithDir(alias, euid, type);
+        if (!access(filepath8.string(), R_OK | W_OK)) return filepath8;
+    }
+
+    // They might be using a granted key.
+    auto grant = mGrants.get(uid, alias.string());
+    if (grant) {
+        filepath8 = String8::format(
+            "%s/%s", grant->owner_dir_name_.c_str(),
+            getKeyNameForUid(String8(grant->alias_.c_str()), grant->owner_uid_, type).c_str());
+        if (!access(filepath8.string(), R_OK | W_OK)) return filepath8;
+    }
+    return {};
+}
+
+void KeyStore::resetUser(uid_t userId, bool keepUnenryptedEntries) {
+    android::String8 prefix("");
+    android::Vector<android::String16> aliases;
+    UserState* userState = getUserState(userId);
+    if (list(prefix, &aliases, userId) != ResponseCode::NO_ERROR) {
+        return;
+    }
+    for (uint32_t i = 0; i < aliases.size(); i++) {
+        android::String8 filename(aliases[i]);
+        filename = android::String8::format("%s/%s", userState->getUserDirName(),
+                                            getKeyName(filename, TYPE_ANY).string());
+        bool shouldDelete = true;
+        if (keepUnenryptedEntries) {
+            Blob blob;
+            ResponseCode rc = get(filename, &blob, ::TYPE_ANY, userId);
+
+            switch (rc) {
+            case ResponseCode::SYSTEM_ERROR:
+            case ResponseCode::VALUE_CORRUPTED:
+                // If we can't read blobs, delete them.
+                shouldDelete = true;
+                break;
+
+            case ResponseCode::NO_ERROR:
+            case ResponseCode::LOCKED:
+                // Delete encrypted blobs but keep unencrypted blobs and super-encrypted blobs.  We
+                // need to keep super-encrypted blobs so we can report that the user is
+                // unauthenticated if a caller tries to use them, rather than reporting that they
+                // don't exist.
+                shouldDelete = blob.isEncrypted();
+                break;
+
+            default:
+                ALOGE("Got unexpected return code %d from KeyStore::get()", rc);
+                // This shouldn't happen.  To be on the safe side, delete it.
+                shouldDelete = true;
+                break;
+            }
+        }
+        if (shouldDelete) {
+            del(filename, ::TYPE_ANY, userId);
+
+            // del() will fail silently if no cached characteristics are present for this alias.
+            android::String8 chr_filename(aliases[i]);
+            chr_filename = android::String8::format(
+                "%s/%s", userState->getUserDirName(),
+                getKeyName(chr_filename, TYPE_KEY_CHARACTERISTICS).string());
+            del(chr_filename, ::TYPE_KEY_CHARACTERISTICS, userId);
+        }
+    }
+    if (!userState->deleteMasterKey()) {
+        ALOGE("Failed to delete user %d's master key", userId);
+    }
+    if (!keepUnenryptedEntries) {
+        if (!userState->reset()) {
+            ALOGE("Failed to remove user %d's directory", userId);
+        }
+    }
+}
+
+bool KeyStore::isEmpty(uid_t userId) const {
+    const UserState* userState = getUserState(userId);
+    if (userState == NULL) {
+        return true;
+    }
+
+    DIR* dir = opendir(userState->getUserDirName());
+    if (!dir) {
+        return true;
+    }
+
+    bool result = true;
+    struct dirent* file;
+    while ((file = readdir(dir)) != NULL) {
+        // We only care about files.
+        if (file->d_type != DT_REG) {
+            continue;
+        }
+
+        // Skip anything that starts with a "."
+        if (file->d_name[0] == '.') {
+            continue;
+        }
+
+        result = false;
+        break;
+    }
+    closedir(dir);
+    return result;
+}
+
+void KeyStore::lock(uid_t userId) {
+    UserState* userState = getUserState(userId);
+    userState->zeroizeMasterKeysInMemory();
+    userState->setState(STATE_LOCKED);
+}
+
+ResponseCode KeyStore::get(const char* filename, Blob* keyBlob, const BlobType type, uid_t userId) {
+    UserState* userState = getUserState(userId);
+    ResponseCode rc =
+        keyBlob->readBlob(filename, userState->getEncryptionKey(), userState->getState());
+    if (rc != ResponseCode::NO_ERROR) {
+        return rc;
+    }
+
+    const uint8_t version = keyBlob->getVersion();
+    if (version < CURRENT_BLOB_VERSION) {
+        /* If we upgrade the key, we need to write it to disk again. Then
+         * it must be read it again since the blob is encrypted each time
+         * it's written.
+         */
+        if (upgradeBlob(filename, keyBlob, version, type, userId)) {
+            if ((rc = this->put(filename, keyBlob, userId)) != ResponseCode::NO_ERROR ||
+                (rc = keyBlob->readBlob(filename, userState->getEncryptionKey(),
+                                        userState->getState())) != ResponseCode::NO_ERROR) {
+                return rc;
+            }
+        }
+    }
+
+    /*
+     * This will upgrade software-backed keys to hardware-backed keys.
+     */
+    if (rc == ResponseCode::NO_ERROR && type == TYPE_KEY_PAIR && keyBlob->isFallback()) {
+        ResponseCode imported =
+            importKey(keyBlob->getValue(), keyBlob->getLength(), filename, userId,
+                      keyBlob->isEncrypted() ? KEYSTORE_FLAG_ENCRYPTED : KEYSTORE_FLAG_NONE);
+
+        // The HAL allowed the import, reget the key to have the "fresh" version.
+        if (imported == ResponseCode::NO_ERROR) {
+            rc = get(filename, keyBlob, TYPE_KEY_PAIR, userId);
+        }
+    }
+
+    // Keymaster 0.3 keys are valid keymaster 1.0 keys, so silently upgrade.
+    if (keyBlob->getType() == TYPE_KEY_PAIR) {
+        keyBlob->setType(TYPE_KEYMASTER_10);
+        rc = this->put(filename, keyBlob, userId);
+    }
+
+    if (type != TYPE_ANY && keyBlob->getType() != type) {
+        ALOGW("key found but type doesn't match: %d vs %d", keyBlob->getType(), type);
+        return ResponseCode::KEY_NOT_FOUND;
+    }
+
+    return rc;
+}
+
+ResponseCode KeyStore::put(const char* filename, Blob* keyBlob, uid_t userId) {
+    UserState* userState = getUserState(userId);
+    return keyBlob->writeBlob(filename, userState->getEncryptionKey(), userState->getState(),
+                              mEntropy);
+}
+
+static NullOr<std::tuple<uid_t, std::string>> filename2UidAlias(const std::string& filename);
+
+ResponseCode KeyStore::del(const char* filename, const BlobType type, uid_t userId) {
+    Blob keyBlob;
+    auto uidAlias = filename2UidAlias(filename);
+    uid_t uid;
+    std::string alias;
+    if (uidAlias.isOk()) {
+        std::tie(uid, alias) = std::move(uidAlias).value();
+    }
+    ResponseCode rc = get(filename, &keyBlob, type, userId);
+    if (rc == ResponseCode::VALUE_CORRUPTED) {
+        // The file is corrupt, the best we can do is rm it.
+        if (uidAlias.isOk()) {
+            // remove possible grants
+            mGrants.removeAllGrantsToKey(uid, alias);
+        }
+        return (unlink(filename) && errno != ENOENT) ? ResponseCode::SYSTEM_ERROR
+                                                     : ResponseCode::NO_ERROR;
+    }
+    if (rc != ResponseCode::NO_ERROR) {
+        return rc;
+    }
+
+    auto& dev = getDevice(keyBlob);
+
+    if (keyBlob.getType() == ::TYPE_KEY_PAIR || keyBlob.getType() == ::TYPE_KEYMASTER_10) {
+        auto ret = KS_HANDLE_HIDL_ERROR(dev->deleteKey(blob2hidlVec(keyBlob)));
+
+        // A device doesn't have to implement delete_key.
+        if (ret != ErrorCode::OK && ret != ErrorCode::UNIMPLEMENTED)
+            return ResponseCode::SYSTEM_ERROR;
+    }
+
+    rc =
+        (unlink(filename) && errno != ENOENT) ? ResponseCode::SYSTEM_ERROR : ResponseCode::NO_ERROR;
+
+    if (rc == ResponseCode::NO_ERROR && keyBlob.getType() != ::TYPE_KEY_CHARACTERISTICS) {
+        // now that we have successfully deleted a key, let's make sure there are no stale grants
+        if (uidAlias.isOk()) {
+            mGrants.removeAllGrantsToKey(uid, alias);
+        }
+    }
+    return rc;
+}
+
+/*
+ * Converts from the "escaped" format on disk to actual name.
+ * This will be smaller than the input string.
+ *
+ * Characters that should combine with the next at the end will be truncated.
+ */
+static size_t decode_key_length(const char* in, size_t length) {
+    size_t outLength = 0;
+
+    for (const char* end = in + length; in < end; in++) {
+        /* This combines with the next character. */
+        if (*in < '0' || *in > '~') {
+            continue;
+        }
+
+        outLength++;
+    }
+    return outLength;
+}
+
+static void decode_key(char* out, const char* in, size_t length) {
+    for (const char* end = in + length; in < end; in++) {
+        if (*in < '0' || *in > '~') {
+            /* Truncate combining characters at the end. */
+            if (in + 1 >= end) {
+                break;
+            }
+
+            *out = (*in++ - '+') << 6;
+            *out++ |= (*in - '0') & 0x3F;
+        } else {
+            *out++ = *in;
+        }
+    }
+    *out = '\0';
+}
+
+static NullOr<std::tuple<uid_t, std::string>> filename2UidAlias(const std::string& filepath) {
+    auto filenamebase = filepath.find_last_of('/');
+    std::string filename =
+        filenamebase == std::string::npos ? filepath : filepath.substr(filenamebase + 1);
+
+    if (filename[0] == '.') return {};
+
+    auto sep = filename.find('_');
+    if (sep == std::string::npos) return {};
+
+    std::stringstream s(filename.substr(0, sep));
+    uid_t uid;
+    s >> uid;
+    if (!s) return {};
+
+    auto alias = filename.substr(sep + 1);
+
+    std::vector<char> alias_buffer(decode_key_length(alias.c_str(), alias.size()) + 1);
+
+    decode_key(alias_buffer.data(), alias.c_str(), alias.size());
+    return std::tuple<uid_t, std::string>(uid, alias_buffer.data());
+}
+
+ResponseCode KeyStore::list(const android::String8& prefix,
+                            android::Vector<android::String16>* matches, uid_t userId) {
+
+    UserState* userState = getUserState(userId);
+    size_t n = prefix.length();
+
+    DIR* dir = opendir(userState->getUserDirName());
+    if (!dir) {
+        ALOGW("can't open directory for user: %s", strerror(errno));
+        return ResponseCode::SYSTEM_ERROR;
+    }
+
+    struct dirent* file;
+    while ((file = readdir(dir)) != NULL) {
+        // We only care about files.
+        if (file->d_type != DT_REG) {
+            continue;
+        }
+
+        // Skip anything that starts with a "."
+        if (file->d_name[0] == '.') {
+            continue;
+        }
+
+        if (!strncmp(prefix.string(), file->d_name, n)) {
+            const char* p = &file->d_name[n];
+            size_t plen = strlen(p);
+
+            size_t extra = decode_key_length(p, plen);
+            char* match = (char*)malloc(extra + 1);
+            if (match != NULL) {
+                decode_key(match, p, plen);
+                matches->push(android::String16(match, extra));
+                free(match);
+            } else {
+                ALOGW("could not allocate match of size %zd", extra);
+            }
+        }
+    }
+    closedir(dir);
+    return ResponseCode::NO_ERROR;
+}
+
+std::string KeyStore::addGrant(const char* alias, uid_t granterUid, uid_t granteeUid) {
+    return mGrants.put(granteeUid, alias, getUserStateByUid(granterUid)->getUserDirName(),
+                       granterUid);
+}
+
+bool KeyStore::removeGrant(const char* alias, const uid_t granterUid, const uid_t granteeUid) {
+    return mGrants.removeByFileAlias(granteeUid, granterUid, alias);
+}
+void KeyStore::removeAllGrantsToUid(const uid_t granteeUid) {
+    mGrants.removeAllGrantsToUid(granteeUid);
+}
+
+ResponseCode KeyStore::importKey(const uint8_t* key, size_t keyLen, const char* filename,
+                                 uid_t userId, int32_t flags) {
+    Unique_PKCS8_PRIV_KEY_INFO pkcs8(d2i_PKCS8_PRIV_KEY_INFO(NULL, &key, keyLen));
+    if (!pkcs8.get()) {
+        return ResponseCode::SYSTEM_ERROR;
+    }
+    Unique_EVP_PKEY pkey(EVP_PKCS82PKEY(pkcs8.get()));
+    if (!pkey.get()) {
+        return ResponseCode::SYSTEM_ERROR;
+    }
+    int type = EVP_PKEY_type(pkey->type);
+    AuthorizationSet params;
+    add_legacy_key_authorizations(type, &params);
+    switch (type) {
+    case EVP_PKEY_RSA:
+        params.push_back(TAG_ALGORITHM, Algorithm::RSA);
+        break;
+    case EVP_PKEY_EC:
+        params.push_back(TAG_ALGORITHM, Algorithm::EC);
+        break;
+    default:
+        ALOGW("Unsupported key type %d", type);
+        return ResponseCode::SYSTEM_ERROR;
+    }
+
+    AuthorizationSet opParams(params);
+    hidl_vec<uint8_t> blob;
+
+    ErrorCode error;
+    auto hidlCb = [&](ErrorCode ret, const hidl_vec<uint8_t>& keyBlob,
+                      const KeyCharacteristics& /* ignored */) {
+        error = ret;
+        if (error != ErrorCode::OK) return;
+        blob = keyBlob;
+    };
+    auto input = blob2hidlVec(key, keyLen);
+
+    ErrorCode rc = KS_HANDLE_HIDL_ERROR(
+        mDevice->importKey(params.hidl_data(), KeyFormat::PKCS8, input, hidlCb));
+    if (rc != ErrorCode::OK) return ResponseCode::SYSTEM_ERROR;
+    if (error != ErrorCode::OK) {
+        ALOGE("Keymaster error %d importing key pair", error);
+        return ResponseCode::SYSTEM_ERROR;
+    }
+
+    Blob keyBlob(&blob[0], blob.size(), NULL, 0, TYPE_KEYMASTER_10);
+
+    keyBlob.setEncrypted(flags & KEYSTORE_FLAG_ENCRYPTED);
+    keyBlob.setFallback(false);
+
+    return put(filename, &keyBlob, userId);
+}
+
+bool KeyStore::isHardwareBacked(const android::String16& /*keyType*/) const {
+    using ::android::hardware::hidl_string;
+    if (mDevice == NULL) {
+        ALOGW("can't get keymaster device");
+        return false;
+    }
+
+    bool isSecure = false;
+    auto hidlcb = [&](bool _isSecure, bool, bool, bool, bool, const hidl_string&,
+                      const hidl_string&) { isSecure = _isSecure; };
+    auto rc = mDevice->getHardwareFeatures(hidlcb);
+    if (!rc.isOk()) {
+        ALOGE("Communication with keymaster HAL failed while retrieving hardware features (%s)",
+              rc.description().c_str());
+        return false;
+    }
+    return isSecure;
+}
+
+ResponseCode KeyStore::getKeyForName(Blob* keyBlob, const android::String8& keyName,
+                                     const uid_t uid, const BlobType type) {
+    auto filepath8 = getBlobFileNameIfExists(keyName, uid, type);
+    uid_t userId = get_user_id(uid);
+
+    if (filepath8.isOk()) return get(filepath8.value().string(), keyBlob, type, userId);
+
+    return ResponseCode::KEY_NOT_FOUND;
+}
+
+UserState* KeyStore::getUserState(uid_t userId) {
+    for (android::Vector<UserState*>::iterator it(mMasterKeys.begin()); it != mMasterKeys.end();
+         it++) {
+        UserState* state = *it;
+        if (state->getUserId() == userId) {
+            return state;
+        }
+    }
+
+    UserState* userState = new UserState(userId);
+    if (!userState->initialize()) {
+        /* There's not much we can do if initialization fails. Trying to
+         * unlock the keystore for that user will fail as well, so any
+         * subsequent request for this user will just return SYSTEM_ERROR.
+         */
+        ALOGE("User initialization failed for %u; subsuquent operations will fail", userId);
+    }
+    mMasterKeys.add(userState);
+    return userState;
+}
+
+UserState* KeyStore::getUserStateByUid(uid_t uid) {
+    uid_t userId = get_user_id(uid);
+    return getUserState(userId);
+}
+
+const UserState* KeyStore::getUserState(uid_t userId) const {
+    for (android::Vector<UserState*>::const_iterator it(mMasterKeys.begin());
+         it != mMasterKeys.end(); it++) {
+        UserState* state = *it;
+        if (state->getUserId() == userId) {
+            return state;
+        }
+    }
+
+    return NULL;
+}
+
+const UserState* KeyStore::getUserStateByUid(uid_t uid) const {
+    uid_t userId = get_user_id(uid);
+    return getUserState(userId);
+}
+
+bool KeyStore::upgradeBlob(const char* filename, Blob* blob, const uint8_t oldVersion,
+                           const BlobType type, uid_t userId) {
+    bool updated = false;
+    uint8_t version = oldVersion;
+
+    /* From V0 -> V1: All old types were unknown */
+    if (version == 0) {
+        ALOGV("upgrading to version 1 and setting type %d", type);
+
+        blob->setType(type);
+        if (type == TYPE_KEY_PAIR) {
+            importBlobAsKey(blob, filename, userId);
+        }
+        version = 1;
+        updated = true;
+    }
+
+    /* From V1 -> V2: All old keys were encrypted */
+    if (version == 1) {
+        ALOGV("upgrading to version 2");
+
+        blob->setEncrypted(true);
+        version = 2;
+        updated = true;
+    }
+
+    /*
+     * If we've updated, set the key blob to the right version
+     * and write it.
+     */
+    if (updated) {
+        ALOGV("updated and writing file %s", filename);
+        blob->setVersion(version);
+    }
+
+    return updated;
+}
+
+struct BIO_Delete {
+    void operator()(BIO* p) const { BIO_free(p); }
+};
+typedef std::unique_ptr<BIO, BIO_Delete> Unique_BIO;
+
+ResponseCode KeyStore::importBlobAsKey(Blob* blob, const char* filename, uid_t userId) {
+    // We won't even write to the blob directly with this BIO, so const_cast is okay.
+    Unique_BIO b(BIO_new_mem_buf(const_cast<uint8_t*>(blob->getValue()), blob->getLength()));
+    if (b.get() == NULL) {
+        ALOGE("Problem instantiating BIO");
+        return ResponseCode::SYSTEM_ERROR;
+    }
+
+    Unique_EVP_PKEY pkey(PEM_read_bio_PrivateKey(b.get(), NULL, NULL, NULL));
+    if (pkey.get() == NULL) {
+        ALOGE("Couldn't read old PEM file");
+        return ResponseCode::SYSTEM_ERROR;
+    }
+
+    Unique_PKCS8_PRIV_KEY_INFO pkcs8(EVP_PKEY2PKCS8(pkey.get()));
+    int len = i2d_PKCS8_PRIV_KEY_INFO(pkcs8.get(), NULL);
+    if (len < 0) {
+        ALOGE("Couldn't measure PKCS#8 length");
+        return ResponseCode::SYSTEM_ERROR;
+    }
+
+    std::unique_ptr<unsigned char[]> pkcs8key(new unsigned char[len]);
+    uint8_t* tmp = pkcs8key.get();
+    if (i2d_PKCS8_PRIV_KEY_INFO(pkcs8.get(), &tmp) != len) {
+        ALOGE("Couldn't convert to PKCS#8");
+        return ResponseCode::SYSTEM_ERROR;
+    }
+
+    ResponseCode rc = importKey(pkcs8key.get(), len, filename, userId,
+                                blob->isEncrypted() ? KEYSTORE_FLAG_ENCRYPTED : KEYSTORE_FLAG_NONE);
+    if (rc != ResponseCode::NO_ERROR) {
+        return rc;
+    }
+
+    return get(filename, blob, TYPE_KEY_PAIR, userId);
+}
+
+void KeyStore::readMetaData() {
+    int in = TEMP_FAILURE_RETRY(open(sMetaDataFile, O_RDONLY));
+    if (in < 0) {
+        return;
+    }
+    size_t fileLength = readFully(in, (uint8_t*)&mMetaData, sizeof(mMetaData));
+    if (fileLength != sizeof(mMetaData)) {
+        ALOGI("Metadata file is %zd bytes (%zd experted); upgrade?", fileLength, sizeof(mMetaData));
+    }
+    close(in);
+}
+
+void KeyStore::writeMetaData() {
+    const char* tmpFileName = ".metadata.tmp";
+    int out =
+        TEMP_FAILURE_RETRY(open(tmpFileName, O_WRONLY | O_TRUNC | O_CREAT, S_IRUSR | S_IWUSR));
+    if (out < 0) {
+        ALOGE("couldn't write metadata file: %s", strerror(errno));
+        return;
+    }
+    size_t fileLength = writeFully(out, (uint8_t*)&mMetaData, sizeof(mMetaData));
+    if (fileLength != sizeof(mMetaData)) {
+        ALOGI("Could only write %zd bytes to metadata file (%zd expected)", fileLength,
+              sizeof(mMetaData));
+    }
+    close(out);
+    rename(tmpFileName, sMetaDataFile);
+}
+
+bool KeyStore::upgradeKeystore() {
+    bool upgraded = false;
+
+    if (mMetaData.version == 0) {
+        UserState* userState = getUserStateByUid(0);
+
+        // Initialize first so the directory is made.
+        userState->initialize();
+
+        // Migrate the old .masterkey file to user 0.
+        if (access(sOldMasterKey, R_OK) == 0) {
+            if (rename(sOldMasterKey, userState->getMasterKeyFileName()) < 0) {
+                ALOGE("couldn't migrate old masterkey: %s", strerror(errno));
+                return false;
+            }
+        }
+
+        // Initialize again in case we had a key.
+        userState->initialize();
+
+        // Try to migrate existing keys.
+        DIR* dir = opendir(".");
+        if (!dir) {
+            // Give up now; maybe we can upgrade later.
+            ALOGE("couldn't open keystore's directory; something is wrong");
+            return false;
+        }
+
+        struct dirent* file;
+        while ((file = readdir(dir)) != NULL) {
+            // We only care about files.
+            if (file->d_type != DT_REG) {
+                continue;
+            }
+
+            // Skip anything that starts with a "."
+            if (file->d_name[0] == '.') {
+                continue;
+            }
+
+            // Find the current file's user.
+            char* end;
+            unsigned long thisUid = strtoul(file->d_name, &end, 10);
+            if (end[0] != '_' || end[1] == 0) {
+                continue;
+            }
+            UserState* otherUser = getUserStateByUid(thisUid);
+            if (otherUser->getUserId() != 0) {
+                unlinkat(dirfd(dir), file->d_name, 0);
+            }
+
+            // Rename the file into user directory.
+            DIR* otherdir = opendir(otherUser->getUserDirName());
+            if (otherdir == NULL) {
+                ALOGW("couldn't open user directory for rename");
+                continue;
+            }
+            if (renameat(dirfd(dir), file->d_name, dirfd(otherdir), file->d_name) < 0) {
+                ALOGW("couldn't rename blob: %s: %s", file->d_name, strerror(errno));
+            }
+            closedir(otherdir);
+        }
+        closedir(dir);
+
+        mMetaData.version = 1;
+        upgraded = true;
+    }
+
+    return upgraded;
+}