FsCrypt update: support fscrypt policies v1 and v2
This patchset introduces support decryption for Android 11. In this update we deprecate ext4crypt. To specify the policy version to use, use TW_USE_FSCRYPT_POLICY := 1 or TW_USE_FSCRYPT_POLICY := 2. By default policy version will be set to 2 if this variable is omitted. Change-Id: I62a29c1bef36c259ec4b11259f71be613d20a112
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bigbiff
@@ -16,10 +16,10 @@
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#include "KeyStorage.h"
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#include "Checkpoint.h"
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#include "Keymaster.h"
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#include "ScryptParameters.h"
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#include "Utils.h"
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#include "Checkpoint.h"
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#include <thread>
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#include <vector>
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@@ -37,23 +37,20 @@
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#include <android-base/file.h>
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#include <android-base/logging.h>
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#include <android-base/unique_fd.h>
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#include <android-base/properties.h>
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#include <android-base/unique_fd.h>
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#include <cutils/properties.h>
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#include <hardware/hw_auth_token.h>
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#include <keymasterV4_0/authorization_set.h>
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#include <keymasterV4_0/keymaster_utils.h>
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#include <keymasterV4_1/authorization_set.h>
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#include <keymasterV4_1/keymaster_utils.h>
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extern "C" {
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#include "crypto_scrypt.h"
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}
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namespace android {
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namespace vold {
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const KeyAuthentication kEmptyAuthentication{"", ""};
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static constexpr size_t AES_KEY_BYTES = 32;
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@@ -64,7 +61,6 @@ static constexpr size_t SECDISCARDABLE_BYTES = 1 << 14;
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static constexpr size_t STRETCHED_BYTES = 1 << 6;
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static constexpr uint32_t AUTH_TIMEOUT = 30; // Seconds
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constexpr int EXT4_AES_256_XTS_KEY_SIZE = 64;
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static const char* kCurrentVersion = "1";
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static const char* kRmPath = "/system/bin/rm";
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@@ -123,70 +119,42 @@ static bool generateKeymasterKey(Keymaster& keymaster, const KeyAuthentication&
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return false;
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}
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const hw_auth_token_t* at = reinterpret_cast<const hw_auth_token_t*>(auth.token.data());
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paramBuilder.Authorization(km::TAG_USER_SECURE_ID, at->user_id);
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auto user_id = at->user_id; // Make a copy because at->user_id is unaligned.
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paramBuilder.Authorization(km::TAG_USER_SECURE_ID, user_id);
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paramBuilder.Authorization(km::TAG_USER_AUTH_TYPE, km::HardwareAuthenticatorType::PASSWORD);
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paramBuilder.Authorization(km::TAG_AUTH_TIMEOUT, AUTH_TIMEOUT);
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}
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return keymaster.generateKey(paramBuilder, key);
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auto paramsWithRollback = paramBuilder;
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paramsWithRollback.Authorization(km::TAG_ROLLBACK_RESISTANCE);
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// Generate rollback-resistant key if possible.
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return keymaster.generateKey(paramsWithRollback, key) ||
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keymaster.generateKey(paramBuilder, key);
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}
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bool generateWrappedKey(userid_t user_id, KeyType key_type,
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KeyBuffer* key) {
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bool generateWrappedStorageKey(KeyBuffer* key) {
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Keymaster keymaster;
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if (!keymaster) return false;
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*key = KeyBuffer(EXT4_AES_256_XTS_KEY_SIZE);
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std::string key_temp;
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auto paramBuilder = km::AuthorizationSetBuilder()
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.AesEncryptionKey(AES_KEY_BYTES * 8)
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.GcmModeMinMacLen(GCM_MAC_BYTES * 8)
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.Authorization(km::TAG_USER_ID, user_id);
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km::KeyParameter param1;
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param1.tag = (km::Tag) (android::hardware::keymaster::V4_0::KM_TAG_FBE_ICE);
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param1.f.boolValue = true;
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paramBuilder.push_back(param1);
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km::KeyParameter param2;
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if ((key_type == KeyType::DE_USER) || (key_type == KeyType::DE_SYS || (key_type == KeyType::ME))) {
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param2.tag = (km::Tag) (android::hardware::keymaster::V4_0::KM_TAG_KEY_TYPE);
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param2.f.integer = 0;
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} else if (key_type == KeyType::CE_USER) {
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param2.tag = (km::Tag) (android::hardware::keymaster::V4_0::KM_TAG_KEY_TYPE);
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param2.f.integer = 1;
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}
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paramBuilder.push_back(param2);
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auto paramBuilder = km::AuthorizationSetBuilder().AesEncryptionKey(AES_KEY_BYTES * 8);
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paramBuilder.Authorization(km::TAG_ROLLBACK_RESISTANCE);
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paramBuilder.Authorization(km::TAG_STORAGE_KEY);
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if (!keymaster.generateKey(paramBuilder, &key_temp)) return false;
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*key = KeyBuffer(key_temp.size());
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memcpy(reinterpret_cast<void*>(key->data()), key_temp.c_str(), key->size());
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return true;
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}
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bool getEphemeralWrappedKey(km::KeyFormat format, KeyBuffer& kmKey, KeyBuffer* key) {
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std::string key_temp;
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bool exportWrappedStorageKey(const KeyBuffer& kmKey, KeyBuffer* key) {
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Keymaster keymaster;
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if (!keymaster) return false;
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std::string key_temp;
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//Export once, if upgrade needed, upgrade and export again
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bool export_again = true;
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while (export_again) {
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export_again = false;
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auto ret = keymaster.exportKey(format, kmKey, "!", "!", &key_temp);
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if (ret == km::ErrorCode::OK) {
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*key = KeyBuffer(key_temp.size());
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memcpy(reinterpret_cast<void*>(key->data()), key_temp.c_str(), key->size());
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return true;
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}
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if (ret != km::ErrorCode::KEY_REQUIRES_UPGRADE) return false;
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LOG(DEBUG) << "Upgrading key";
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std::string kmKeyStr(reinterpret_cast<const char*>(kmKey.data()), kmKey.size());
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std::string newKey;
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if (!keymaster.upgradeKey(kmKeyStr, km::AuthorizationSet(), &newKey)) return false;
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memcpy(reinterpret_cast<void*>(kmKey.data()), newKey.c_str(), kmKey.size());
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LOG(INFO) << "Key upgraded";
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export_again = true;
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}
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//Should never come here
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return false;
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if (!keymaster.exportKey(kmKey, &key_temp)) return false;
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*key = KeyBuffer(key_temp.size());
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memcpy(reinterpret_cast<void*>(key->data()), key_temp.c_str(), key->size());
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return true;
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}
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static std::pair<km::AuthorizationSet, km::HardwareAuthToken> beginParams(
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@@ -212,7 +180,7 @@ static bool readFileToString(const std::string& filename, std::string* result) {
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static bool readRandomBytesOrLog(size_t count, std::string* out) {
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auto status = ReadRandomBytes(count, *out);
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if (status != OK) {
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if (status != android::OK) {
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LOG(ERROR) << "Random read failed with status: " << status;
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return false;
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}
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@@ -234,27 +202,26 @@ bool readSecdiscardable(const std::string& filename, std::string* hash) {
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return true;
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}
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// static void deferedKmDeleteKey(const std::string& kmkey) {
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// while (!android::base::WaitForProperty("vold.checkpoint_committed", "1")) {
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// LOG(ERROR) << "Wait for boot timed out";
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// }
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// Keymaster keymaster;
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// if (!keymaster || !keymaster.deleteKey(kmkey)) {
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// LOG(ERROR) << "Defered Key deletion failed during upgrade";
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// }
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// }
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static void deferedKmDeleteKey(const std::string& kmkey) {
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while (!android::base::WaitForProperty("vold.checkpoint_committed", "1")) {
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LOG(ERROR) << "Wait for boot timed out";
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}
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Keymaster keymaster;
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if (!keymaster || !keymaster.deleteKey(kmkey)) {
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LOG(ERROR) << "Defered Key deletion failed during upgrade";
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}
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}
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bool kmDeleteKey(Keymaster& keymaster, const std::string& kmKey) {
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return true;
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// bool needs_cp = cp_needsCheckpoint();
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bool needs_cp = cp_needsCheckpoint();
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// if (needs_cp) {
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// std::thread(deferedKmDeleteKey, kmKey).detach();
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// LOG(INFO) << "Deferring Key deletion during upgrade";
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// return true;
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// } else {
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// return keymaster.deleteKey(kmKey);
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// }
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if (needs_cp) {
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std::thread(deferedKmDeleteKey, kmKey).detach();
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LOG(INFO) << "Deferring Key deletion during upgrade";
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return true;
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} else {
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return keymaster.deleteKey(kmKey);
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}
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}
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static KeymasterOperation begin(Keymaster& keymaster, const std::string& dir,
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@@ -283,7 +250,7 @@ static KeymasterOperation begin(Keymaster& keymaster, const std::string& dir,
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// PLOG(ERROR) << "Unable to move upgraded key to location: " << kmKeyPath;
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// return KeymasterOperation();
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// }
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// if (!android::vold::FsyncDirectory(dir)) {
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// if (!::FsyncDirectory(dir)) {
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// LOG(ERROR) << "Key dir sync failed: " << dir;
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// return KeymasterOperation();
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// }
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@@ -292,7 +259,7 @@ static KeymasterOperation begin(Keymaster& keymaster, const std::string& dir,
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// }
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// }
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kmKey = newKey;
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LOG(INFO) << "Key upgraded in memory: " << dir;
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LOG(INFO) << "Key upgraded: " << dir;
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}
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}
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@@ -522,7 +489,7 @@ bool storeKey(const std::string& dir, const KeyAuthentication& auth, const KeyBu
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if (!writeStringToFile(stretching, dir + "/" + kFn_stretching)) return false;
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std::string salt;
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if (stretchingNeedsSalt(stretching)) {
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if (ReadRandomBytes(SALT_BYTES, salt) != OK) {
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if (ReadRandomBytes(SALT_BYTES, salt) != android::OK) {
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LOG(ERROR) << "Random read failed";
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return false;
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}
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@@ -561,7 +528,7 @@ bool storeKeyAtomically(const std::string& key_path, const std::string& tmp_path
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LOG(DEBUG) << "Already exists, destroying: " << tmp_path;
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destroyKey(tmp_path); // May be partially created so ignore errors
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}
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if (!storeKey(tmp_path, auth, key)) return false;
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if (!::storeKey(tmp_path, auth, key)) return false;
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if (rename(tmp_path.c_str(), key_path.c_str()) != 0) {
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PLOG(ERROR) << "Unable to move new key to location: " << key_path;
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return false;
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@@ -653,6 +620,3 @@ bool destroyKey(const std::string& dir) {
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success &= recursiveDeleteKey(dir);
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return success;
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}
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} // namespace vold
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} // namespace android
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