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Remove HardwareAuthToken support from vold::Keymaster am: e13617100d

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Original change: https://android-review.googlesource.com/c/platform/system/vold/+/1640884

Change-Id: Id8528a10d976e94e8bdb4e308d91107b1afdced6
This commit is contained in:
Satya Tangirala 2021-04-08 00:52:35 +00:00 committed by Automerger Merge Worker
commit 695fadddf3
7 changed files with 71 additions and 126 deletions
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35
FsCrypt.cpp
View file

@ -490,7 +490,7 @@ bool fscrypt_init_user0() {
// If this is a non-FBE device that recently left an emulated mode,
// restore user data directories to known-good state.
if (!fscrypt_is_native() && !fscrypt_is_emulated()) {
fscrypt_unlock_user_key(0, 0, "!", "!");
fscrypt_unlock_user_key(0, 0, "!");
}
// In some scenarios (e.g. userspace reboot) we might unmount userdata
@ -625,14 +625,13 @@ static bool parse_hex(const std::string& hex, std::string* result) {
}
static std::optional<android::vold::KeyAuthentication> authentication_from_hex(
const std::string& token_hex, const std::string& secret_hex) {
std::string token, secret;
if (!parse_hex(token_hex, &token)) return std::optional<android::vold::KeyAuthentication>();
const std::string& secret_hex) {
std::string secret;
if (!parse_hex(secret_hex, &secret)) return std::optional<android::vold::KeyAuthentication>();
if (secret.empty()) {
return kEmptyAuthentication;
} else {
return android::vold::KeyAuthentication(token, secret);
return android::vold::KeyAuthentication(secret);
}
}
@ -658,7 +657,7 @@ static bool read_or_create_volkey(const std::string& misc_path, const std::strin
}
auto key_path = volkey_path(misc_path, volume_uuid);
if (!android::vold::MkdirsSync(key_path, 0700)) return false;
android::vold::KeyAuthentication auth("", secdiscardable_hash);
android::vold::KeyAuthentication auth(secdiscardable_hash);
EncryptionOptions options;
if (!get_volume_file_encryption_options(&options)) return false;
@ -701,22 +700,18 @@ static bool fscrypt_rewrap_user_key(userid_t user_id, int serial,
return true;
}
bool fscrypt_add_user_key_auth(userid_t user_id, int serial, const std::string& token_hex,
const std::string& secret_hex) {
LOG(DEBUG) << "fscrypt_add_user_key_auth " << user_id << " serial=" << serial
<< " token_present=" << (token_hex != "!");
bool fscrypt_add_user_key_auth(userid_t user_id, int serial, const std::string& secret_hex) {
LOG(DEBUG) << "fscrypt_add_user_key_auth " << user_id << " serial=" << serial;
if (!fscrypt_is_native()) return true;
auto auth = authentication_from_hex(token_hex, secret_hex);
auto auth = authentication_from_hex(secret_hex);
if (!auth) return false;
return fscrypt_rewrap_user_key(user_id, serial, kEmptyAuthentication, *auth);
}
bool fscrypt_clear_user_key_auth(userid_t user_id, int serial, const std::string& token_hex,
const std::string& secret_hex) {
LOG(DEBUG) << "fscrypt_clear_user_key_auth " << user_id << " serial=" << serial
<< " token_present=" << (token_hex != "!");
bool fscrypt_clear_user_key_auth(userid_t user_id, int serial, const std::string& secret_hex) {
LOG(DEBUG) << "fscrypt_clear_user_key_auth " << user_id << " serial=" << serial;
if (!fscrypt_is_native()) return true;
auto auth = authentication_from_hex(token_hex, secret_hex);
auto auth = authentication_from_hex(secret_hex);
if (!auth) return false;
return fscrypt_rewrap_user_key(user_id, serial, *auth, kEmptyAuthentication);
}
@ -736,16 +731,14 @@ bool fscrypt_fixate_newest_user_key_auth(userid_t user_id) {
}
// TODO: rename to 'install' for consistency, and take flags to know which keys to install
bool fscrypt_unlock_user_key(userid_t user_id, int serial, const std::string& token_hex,
const std::string& secret_hex) {
LOG(DEBUG) << "fscrypt_unlock_user_key " << user_id << " serial=" << serial
<< " token_present=" << (token_hex != "!");
bool fscrypt_unlock_user_key(userid_t user_id, int serial, const std::string& secret_hex) {
LOG(DEBUG) << "fscrypt_unlock_user_key " << user_id << " serial=" << serial;
if (fscrypt_is_native()) {
if (s_ce_policies.count(user_id) != 0) {
LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id;
return true;
}
auto auth = authentication_from_hex(token_hex, secret_hex);
auto auth = authentication_from_hex(secret_hex);
if (!auth) return false;
if (!read_and_install_user_ce_key(user_id, *auth)) {
LOG(ERROR) << "Couldn't read key for " << user_id;

9
FsCrypt.h
View file

@ -23,14 +23,11 @@ bool fscrypt_initialize_systemwide_keys();
bool fscrypt_init_user0();
bool fscrypt_vold_create_user_key(userid_t user_id, int serial, bool ephemeral);
bool fscrypt_destroy_user_key(userid_t user_id);
bool fscrypt_add_user_key_auth(userid_t user_id, int serial, const std::string& token,
const std::string& secret);
bool fscrypt_clear_user_key_auth(userid_t user_id, int serial, const std::string& token,
const std::string& secret);
bool fscrypt_add_user_key_auth(userid_t user_id, int serial, const std::string& secret);
bool fscrypt_clear_user_key_auth(userid_t user_id, int serial, const std::string& secret);
bool fscrypt_fixate_newest_user_key_auth(userid_t user_id);
bool fscrypt_unlock_user_key(userid_t user_id, int serial, const std::string& token,
const std::string& secret);
bool fscrypt_unlock_user_key(userid_t user_id, int serial, const std::string& secret);
bool fscrypt_lock_user_key(userid_t user_id);
bool fscrypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_id, int serial,

115
KeyStorage.cpp
View file

@ -57,7 +57,7 @@ extern "C" {
namespace android {
namespace vold {
const KeyAuthentication kEmptyAuthentication{"", ""};
const KeyAuthentication kEmptyAuthentication{""};
static constexpr size_t AES_KEY_BYTES = 32;
static constexpr size_t GCM_NONCE_BYTES = 12;
@ -149,28 +149,15 @@ static bool generateKeymasterKey(Keymaster& keymaster,
return true;
}
static bool generateKeyStorageKey(Keymaster& keymaster, const KeyAuthentication& auth,
const std::string& appId, std::string* key) {
auto paramBuilder = km::AuthorizationSetBuilder()
.AesEncryptionKey(AES_KEY_BYTES * 8)
.GcmModeMinMacLen(GCM_MAC_BYTES * 8)
.Authorization(km::TAG_APPLICATION_ID, km::support::blob2hidlVec(appId));
if (auth.token.empty()) {
LOG(DEBUG) << "Generating \"key storage\" key that doesn't need auth token";
paramBuilder.Authorization(km::TAG_NO_AUTH_REQUIRED);
} else {
LOG(DEBUG) << "Generating \"key storage\" key that needs auth token";
if (auth.token.size() != sizeof(hw_auth_token_t)) {
LOG(ERROR) << "Auth token should be " << sizeof(hw_auth_token_t) << " bytes, was "
<< auth.token.size() << " bytes";
return false;
}
const hw_auth_token_t* at = reinterpret_cast<const hw_auth_token_t*>(auth.token.data());
auto user_id = at->user_id; // Make a copy because at->user_id is unaligned.
paramBuilder.Authorization(km::TAG_USER_SECURE_ID, user_id);
paramBuilder.Authorization(km::TAG_USER_AUTH_TYPE, km::HardwareAuthenticatorType::PASSWORD);
paramBuilder.Authorization(km::TAG_AUTH_TIMEOUT, AUTH_TIMEOUT);
}
static bool generateKeyStorageKey(Keymaster& keymaster, const std::string& appId,
std::string* key) {
auto paramBuilder =
km::AuthorizationSetBuilder()
.AesEncryptionKey(AES_KEY_BYTES * 8)
.GcmModeMinMacLen(GCM_MAC_BYTES * 8)
.Authorization(km::TAG_APPLICATION_ID, km::support::blob2hidlVec(appId))
.Authorization(km::TAG_NO_AUTH_REQUIRED);
LOG(DEBUG) << "Generating \"key storage\" key that doesn't need auth token";
return generateKeymasterKey(keymaster, paramBuilder, key);
}
@ -197,17 +184,10 @@ bool exportWrappedStorageKey(const KeyBuffer& kmKey, KeyBuffer* key) {
return true;
}
static std::pair<km::AuthorizationSet, km::HardwareAuthToken> beginParams(
const KeyAuthentication& auth, const std::string& appId) {
auto paramBuilder = km::AuthorizationSetBuilder()
.GcmModeMacLen(GCM_MAC_BYTES * 8)
.Authorization(km::TAG_APPLICATION_ID, km::support::blob2hidlVec(appId));
km::HardwareAuthToken authToken;
if (!auth.token.empty()) {
LOG(DEBUG) << "Supplying auth token to Keymaster";
authToken = km::support::hidlVec2AuthToken(km::support::blob2hidlVec(auth.token));
}
return {paramBuilder, authToken};
static km::AuthorizationSet beginParams(const std::string& appId) {
return km::AuthorizationSetBuilder()
.GcmModeMacLen(GCM_MAC_BYTES * 8)
.Authorization(km::TAG_APPLICATION_ID, km::support::blob2hidlVec(appId));
}
static bool readFileToString(const std::string& filename, std::string* result) {
@ -343,7 +323,6 @@ static KeymasterOperation BeginKeymasterOp(Keymaster& keymaster, const std::stri
km::KeyPurpose purpose,
const km::AuthorizationSet& keyParams,
const km::AuthorizationSet& opParams,
const km::HardwareAuthToken& authToken,
km::AuthorizationSet* outParams) {
km::AuthorizationSet inParams(keyParams);
inParams.append(opParams.begin(), opParams.end());
@ -365,7 +344,7 @@ static KeymasterOperation BeginKeymasterOp(Keymaster& keymaster, const std::stri
if (!readFileToString(blob_file, &blob)) return KeymasterOperation();
}
auto opHandle = keymaster.begin(purpose, blob, inParams, authToken, outParams);
auto opHandle = keymaster.begin(purpose, blob, inParams, outParams);
if (opHandle) return opHandle;
if (opHandle.errorCode() != km::ErrorCode::KEY_REQUIRES_UPGRADE) return opHandle;
@ -386,17 +365,16 @@ static KeymasterOperation BeginKeymasterOp(Keymaster& keymaster, const std::stri
LOG(INFO) << "Key upgraded: " << blob_file;
}
return keymaster.begin(purpose, blob, inParams, authToken, outParams);
return keymaster.begin(purpose, blob, inParams, outParams);
}
static bool encryptWithKeymasterKey(Keymaster& keymaster, const std::string& dir,
const km::AuthorizationSet& keyParams,
const km::HardwareAuthToken& authToken,
const KeyBuffer& message, std::string* ciphertext) {
km::AuthorizationSet opParams;
km::AuthorizationSet outParams;
auto opHandle = BeginKeymasterOp(keymaster, dir, km::KeyPurpose::ENCRYPT, keyParams, opParams,
authToken, &outParams);
&outParams);
if (!opHandle) return false;
auto nonceBlob = outParams.GetTagValue(km::TAG_NONCE);
if (!nonceBlob.isOk()) {
@ -419,14 +397,13 @@ static bool encryptWithKeymasterKey(Keymaster& keymaster, const std::string& dir
static bool decryptWithKeymasterKey(Keymaster& keymaster, const std::string& dir,
const km::AuthorizationSet& keyParams,
const km::HardwareAuthToken& authToken,
const std::string& ciphertext, KeyBuffer* message) {
auto nonce = ciphertext.substr(0, GCM_NONCE_BYTES);
auto bodyAndMac = ciphertext.substr(GCM_NONCE_BYTES);
auto opParams = km::AuthorizationSetBuilder().Authorization(km::TAG_NONCE,
km::support::blob2hidlVec(nonce));
auto opHandle = BeginKeymasterOp(keymaster, dir, km::KeyPurpose::DECRYPT, keyParams, opParams,
authToken, nullptr);
auto opHandle =
BeginKeymasterOp(keymaster, dir, km::KeyPurpose::DECRYPT, keyParams, opParams, nullptr);
if (!opHandle) return false;
if (!opHandle.updateCompletely(bodyAndMac, message)) return false;
if (!opHandle.finish(nullptr)) return false;
@ -434,22 +411,13 @@ static bool decryptWithKeymasterKey(Keymaster& keymaster, const std::string& dir
}
static std::string getStretching(const KeyAuthentication& auth) {
if (!auth.usesKeymaster()) {
return kStretch_none;
} else if (auth.secret.empty()) {
if (auth.usesKeymaster()) {
return kStretch_nopassword;
} else {
char paramstr[PROPERTY_VALUE_MAX];
property_get(SCRYPT_PROP, paramstr, SCRYPT_DEFAULTS);
return std::string() + kStretchPrefix_scrypt + paramstr;
return kStretch_none;
}
}
static bool stretchingNeedsSalt(const std::string& stretching) {
return stretching != kStretch_nopassword && stretching != kStretch_none;
}
static bool stretchSecret(const std::string& stretching, const std::string& secret,
const std::string& salt, std::string* stretched) {
if (stretching == kStretch_nopassword) {
@ -460,22 +428,6 @@ static bool stretchSecret(const std::string& stretching, const std::string& secr
stretched->clear();
} else if (stretching == kStretch_none) {
*stretched = secret;
} else if (std::equal(kStretchPrefix_scrypt.begin(), kStretchPrefix_scrypt.end(),
stretching.begin())) {
int Nf, rf, pf;
if (!parse_scrypt_parameters(stretching.substr(kStretchPrefix_scrypt.size()).c_str(), &Nf,
&rf, &pf)) {
LOG(ERROR) << "Unable to parse scrypt params in stretching: " << stretching;
return false;
}
stretched->assign(STRETCHED_BYTES, '\0');
if (crypto_scrypt(reinterpret_cast<const uint8_t*>(secret.data()), secret.size(),
reinterpret_cast<const uint8_t*>(salt.data()), salt.size(), 1 << Nf,
1 << rf, 1 << pf, reinterpret_cast<uint8_t*>(&(*stretched)[0]),
stretched->size()) != 0) {
LOG(ERROR) << "scrypt failed with params: " << stretching;
return false;
}
} else {
LOG(ERROR) << "Unknown stretching type: " << stretching;
return false;
@ -623,13 +575,6 @@ bool storeKey(const std::string& dir, const KeyAuthentication& auth, const KeyBu
std::string stretching = getStretching(auth);
if (!writeStringToFile(stretching, dir + "/" + kFn_stretching)) return false;
std::string salt;
if (stretchingNeedsSalt(stretching)) {
if (ReadRandomBytes(SALT_BYTES, salt) != OK) {
LOG(ERROR) << "Random read failed";
return false;
}
if (!writeStringToFile(salt, dir + "/" + kFn_salt)) return false;
}
std::string appId;
if (!generateAppId(auth, stretching, salt, secdiscardable_hash, &appId)) return false;
std::string encryptedKey;
@ -637,13 +582,10 @@ bool storeKey(const std::string& dir, const KeyAuthentication& auth, const KeyBu
Keymaster keymaster;
if (!keymaster) return false;
std::string kmKey;
if (!generateKeyStorageKey(keymaster, auth, appId, &kmKey)) return false;
if (!generateKeyStorageKey(keymaster, appId, &kmKey)) return false;
if (!writeStringToFile(kmKey, dir + "/" + kFn_keymaster_key_blob)) return false;
km::AuthorizationSet keyParams;
km::HardwareAuthToken authToken;
std::tie(keyParams, authToken) = beginParams(auth, appId);
if (!encryptWithKeymasterKey(keymaster, dir, keyParams, authToken, key, &encryptedKey))
return false;
km::AuthorizationSet keyParams = beginParams(appId);
if (!encryptWithKeymasterKey(keymaster, dir, keyParams, key, &encryptedKey)) return false;
} else {
if (!encryptWithoutKeymaster(appId, key, &encryptedKey)) return false;
}
@ -684,9 +626,6 @@ bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffe
std::string stretching;
if (!readFileToString(dir + "/" + kFn_stretching, &stretching)) return false;
std::string salt;
if (stretchingNeedsSalt(stretching)) {
if (!readFileToString(dir + "/" + kFn_salt, &salt)) return false;
}
std::string appId;
if (!generateAppId(auth, stretching, salt, secdiscardable_hash, &appId)) return false;
std::string encryptedMessage;
@ -694,10 +633,8 @@ bool retrieveKey(const std::string& dir, const KeyAuthentication& auth, KeyBuffe
if (auth.usesKeymaster()) {
Keymaster keymaster;
if (!keymaster) return false;
km::AuthorizationSet keyParams;
km::HardwareAuthToken authToken;
std::tie(keyParams, authToken) = beginParams(auth, appId);
if (!decryptWithKeymasterKey(keymaster, dir, keyParams, authToken, encryptedMessage, key))
km::AuthorizationSet keyParams = beginParams(appId);
if (!decryptWithKeymasterKey(keymaster, dir, keyParams, encryptedMessage, key))
return false;
} else {
if (!decryptWithoutKeymaster(appId, encryptedMessage, key)) return false;

5
KeyStorage.h
View file

@ -33,11 +33,10 @@ namespace vold {
// If only "secret" is nonempty, it is used to decrypt in a non-Keymaster process.
class KeyAuthentication {
public:
KeyAuthentication(const std::string& t, const std::string& s) : token{t}, secret{s} {};
KeyAuthentication(const std::string& s) : secret{s} {};
bool usesKeymaster() const { return !token.empty() || secret.empty(); };
bool usesKeymaster() const { return secret.empty(); };
const std::string token;
const std::string secret;
};

6
Keymaster.cpp
View file

@ -198,7 +198,6 @@ bool Keymaster::upgradeKey(const std::string& oldKey, const km::AuthorizationSet
KeymasterOperation Keymaster::begin(km::KeyPurpose purpose, const std::string& key,
const km::AuthorizationSet& inParams,
const km::HardwareAuthToken& authToken,
km::AuthorizationSet* outParams) {
auto keyBlob = km::support::blob2hidlVec(key);
uint64_t mOpHandle;
@ -212,7 +211,8 @@ KeymasterOperation Keymaster::begin(km::KeyPurpose purpose, const std::string& k
mOpHandle = operationHandle;
};
auto error = mDevice->begin(purpose, keyBlob, inParams.hidl_data(), authToken, hidlCb);
auto error =
mDevice->begin(purpose, keyBlob, inParams.hidl_data(), km::HardwareAuthToken(), hidlCb);
if (!error.isOk()) {
LOG(ERROR) << "begin failed: " << error.description();
return KeymasterOperation(km::ErrorCode::UNKNOWN_ERROR);
@ -343,7 +343,7 @@ KeymasterSignResult keymaster_sign_object_for_cryptfs_scrypt(
auto paramBuilder = km::AuthorizationSetBuilder().NoDigestOrPadding();
while (true) {
op = dev.begin(km::KeyPurpose::SIGN, key, paramBuilder, km::HardwareAuthToken(), &outParams);
op = dev.begin(km::KeyPurpose::SIGN, key, paramBuilder, &outParams);
if (op.errorCode() == km::ErrorCode::KEY_RATE_LIMIT_EXCEEDED) {
sleep(ratelimit);
continue;

1
Keymaster.h
View file

@ -124,7 +124,6 @@ class Keymaster {
// Begin a new cryptographic operation, collecting output parameters if pointer is non-null
KeymasterOperation begin(km::KeyPurpose purpose, const std::string& key,
const km::AuthorizationSet& inParams,
const km::HardwareAuthToken& authToken,
km::AuthorizationSet* outParams);
bool isSecure();

26
VoldNativeService.cpp
View file

@ -724,13 +724,22 @@ binder::Status VoldNativeService::destroyUserKey(int32_t userId) {
return translateBool(fscrypt_destroy_user_key(userId));
}
static bool token_empty(const std::string& token) {
return token.size() == 0 || token == "!";
}
binder::Status VoldNativeService::addUserKeyAuth(int32_t userId, int32_t userSerial,
const std::string& token,
const std::string& secret) {
ENFORCE_SYSTEM_OR_ROOT;
ACQUIRE_CRYPT_LOCK;
return translateBool(fscrypt_add_user_key_auth(userId, userSerial, token, secret));
if (!token_empty(token)) {
LOG(ERROR) << "Vold doesn't use auth tokens, but non-empty token passed to addUserKeyAuth.";
return binder::Status::fromServiceSpecificError(-EINVAL);
}
return translateBool(fscrypt_add_user_key_auth(userId, userSerial, secret));
}
binder::Status VoldNativeService::clearUserKeyAuth(int32_t userId, int32_t userSerial,
@ -739,7 +748,13 @@ binder::Status VoldNativeService::clearUserKeyAuth(int32_t userId, int32_t userS
ENFORCE_SYSTEM_OR_ROOT;
ACQUIRE_CRYPT_LOCK;
return translateBool(fscrypt_clear_user_key_auth(userId, userSerial, token, secret));
if (!token_empty(token)) {
LOG(ERROR)
<< "Vold doesn't use auth tokens, but non-empty token passed to clearUserKeyAuth.";
return binder::Status::fromServiceSpecificError(-EINVAL);
}
return translateBool(fscrypt_clear_user_key_auth(userId, userSerial, secret));
}
binder::Status VoldNativeService::fixateNewestUserKeyAuth(int32_t userId) {
@ -755,7 +770,12 @@ binder::Status VoldNativeService::unlockUserKey(int32_t userId, int32_t userSeri
ENFORCE_SYSTEM_OR_ROOT;
ACQUIRE_CRYPT_LOCK;
return translateBool(fscrypt_unlock_user_key(userId, userSerial, token, secret));
if (!token_empty(token)) {
LOG(ERROR) << "Vold doesn't use auth tokens, but non-empty token passed to unlockUserKey.";
return binder::Status::fromServiceSpecificError(-EINVAL);
}
return translateBool(fscrypt_unlock_user_key(userId, userSerial, secret));
}
binder::Status VoldNativeService::lockUserKey(int32_t userId) {