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Merge changes If530edaf,I7f11a135,I28412f24,Ia27a61fa,If221e239 into main

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* changes:
  Revert "fskeyring & userspace reboot: support CE keys"
  Evict adoptable storage CE and DE keys when possible
  Don't erase key from s_new_ce_keys on eviction
  Call fscrypt_destroy_volume_keys() under mCryptLock
  Fold read_and_install_user_ce_key() into fscrypt_unlock_user_key()
This commit is contained in:
Eric Biggers 2023-10-06 19:52:39 +00:00 committed by Gerrit Code Review
commit f15785a54d
6 changed files with 129 additions and 229 deletions
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167
FsCrypt.cpp
View file

@ -106,15 +106,25 @@ std::set<userid_t> s_ephemeral_users;
// New CE keys that haven't been committed to disk yet // New CE keys that haven't been committed to disk yet
std::map<userid_t, KeyBuffer> s_new_ce_keys; std::map<userid_t, KeyBuffer> s_new_ce_keys;
// CE key fixation operations that have been deferred to checkpoint commit
std::map<std::string, std::string> s_deferred_fixations;
// The system DE encryption policy // The system DE encryption policy
EncryptionPolicy s_device_policy; EncryptionPolicy s_device_policy;
// Map user ids to encryption policies // Struct that holds the EncryptionPolicy for each CE or DE key that is currently installed
std::map<userid_t, EncryptionPolicy> s_de_policies; // (added to the kernel) for a particular user
std::map<userid_t, EncryptionPolicy> s_ce_policies; struct UserPolicies {
// Internal storage policy. Exists whenever a user's UserPolicies exists at all, and used
// instead of a map entry keyed by an empty UUID to make this invariant explicit.
EncryptionPolicy internal;
// Adoptable storage policies, indexed by (nonempty) volume UUID
std::map<std::string, EncryptionPolicy> adoptable;
};
// CE key fixation operations that have been deferred to checkpoint commit // The currently installed CE and DE keys for each user. Protected by VolumeManager::mCryptLock.
std::map<std::string, std::string> s_deferred_fixations; std::map<userid_t, UserPolicies> s_ce_policies;
std::map<userid_t, UserPolicies> s_de_policies;
} // namespace } // namespace
@ -316,18 +326,6 @@ static bool get_volume_file_encryption_options(EncryptionOptions* options) {
return true; return true;
} }
static bool read_and_install_user_ce_key(userid_t user_id,
const android::vold::KeyAuthentication& auth) {
if (s_ce_policies.count(user_id) != 0) return true;
KeyBuffer ce_key;
if (!read_and_fixate_user_ce_key(user_id, auth, &ce_key)) return false;
EncryptionPolicy ce_policy;
if (!install_storage_key(DATA_MNT_POINT, s_data_options, ce_key, &ce_policy)) return false;
s_ce_policies[user_id] = ce_policy;
LOG(DEBUG) << "Installed ce key for user " << user_id;
return true;
}
// Prepare a directory without assigning it an encryption policy. The directory // Prepare a directory without assigning it an encryption policy. The directory
// will inherit the encryption policy of its parent directory, or will be // will inherit the encryption policy of its parent directory, or will be
// unencrypted if the parent directory is unencrypted. // unencrypted if the parent directory is unencrypted.
@ -410,7 +408,7 @@ static bool create_de_key(userid_t user_id, bool ephemeral) {
return false; return false;
EncryptionPolicy de_policy; EncryptionPolicy de_policy;
if (!install_storage_key(DATA_MNT_POINT, s_data_options, de_key, &de_policy)) return false; if (!install_storage_key(DATA_MNT_POINT, s_data_options, de_key, &de_policy)) return false;
s_de_policies[user_id] = de_policy; s_de_policies[user_id].internal = de_policy;
LOG(INFO) << "Created DE key for user " << user_id; LOG(INFO) << "Created DE key for user " << user_id;
return true; return true;
} }
@ -428,21 +426,11 @@ static bool create_ce_key(userid_t user_id, bool ephemeral) {
} }
EncryptionPolicy ce_policy; EncryptionPolicy ce_policy;
if (!install_storage_key(DATA_MNT_POINT, s_data_options, ce_key, &ce_policy)) return false; if (!install_storage_key(DATA_MNT_POINT, s_data_options, ce_key, &ce_policy)) return false;
s_ce_policies[user_id] = ce_policy; s_ce_policies[user_id].internal = ce_policy;
LOG(INFO) << "Created CE key for user " << user_id; LOG(INFO) << "Created CE key for user " << user_id;
return true; return true;
} }
static bool lookup_policy(const std::map<userid_t, EncryptionPolicy>& key_map, userid_t user_id,
EncryptionPolicy* policy) {
auto refi = key_map.find(user_id);
if (refi == key_map.end()) {
return false;
}
*policy = refi->second;
return true;
}
static bool is_numeric(const char* name) { static bool is_numeric(const char* name) {
for (const char* p = name; *p != '\0'; p++) { for (const char* p = name; *p != '\0'; p++) {
if (!isdigit(*p)) return false; if (!isdigit(*p)) return false;
@ -482,8 +470,8 @@ static bool load_all_de_keys() {
} }
EncryptionPolicy de_policy; EncryptionPolicy de_policy;
if (!install_storage_key(DATA_MNT_POINT, s_data_options, de_key, &de_policy)) return false; if (!install_storage_key(DATA_MNT_POINT, s_data_options, de_key, &de_policy)) return false;
auto ret = s_de_policies.insert({user_id, de_policy}); const auto& [existing, is_new] = s_de_policies.insert({user_id, {de_policy, {}}});
if (!ret.second && ret.first->second != de_policy) { if (!is_new && existing->second.internal != de_policy) {
LOG(ERROR) << "DE policy for user" << user_id << " changed"; LOG(ERROR) << "DE policy for user" << user_id << " changed";
return false; return false;
} }
@ -494,17 +482,6 @@ static bool load_all_de_keys() {
return true; return true;
} }
// Attempt to reinstall CE keys for users that we think are unlocked.
static bool try_reload_ce_keys() {
for (const auto& it : s_ce_policies) {
if (!android::vold::reloadKeyFromSessionKeyring(DATA_MNT_POINT, it.second)) {
LOG(ERROR) << "Failed to load CE key from session keyring for user " << it.first;
return false;
}
}
return true;
}
bool fscrypt_initialize_systemwide_keys() { bool fscrypt_initialize_systemwide_keys() {
LOG(INFO) << "fscrypt_initialize_systemwide_keys"; LOG(INFO) << "fscrypt_initialize_systemwide_keys";
@ -561,8 +538,8 @@ static bool prepare_special_dirs() {
// On first boot, we'll be creating /data/data for the first time, and user // On first boot, we'll be creating /data/data for the first time, and user
// 0's CE key will be installed already since it was just created. Take the // 0's CE key will be installed already since it was just created. Take the
// opportunity to also set the encryption policy of /data/data right away. // opportunity to also set the encryption policy of /data/data right away.
EncryptionPolicy ce_policy; if (s_ce_policies.count(0) != 0) {
if (lookup_policy(s_ce_policies, 0, &ce_policy)) { const EncryptionPolicy& ce_policy = s_ce_policies[0].internal;
if (!prepare_dir_with_policy(data_data_dir, 0771, AID_SYSTEM, AID_SYSTEM, ce_policy)) { if (!prepare_dir_with_policy(data_data_dir, 0771, AID_SYSTEM, AID_SYSTEM, ce_policy)) {
// Preparing /data/data failed, yet we had just generated a new CE // Preparing /data/data failed, yet we had just generated a new CE
// key because one wasn't stored. Before erroring out, try deleting // key because one wasn't stored. Before erroring out, try deleting
@ -633,13 +610,6 @@ bool fscrypt_init_user0() {
return false; return false;
} }
// In some scenarios (e.g. userspace reboot) we might unmount userdata
// without doing a hard reboot. If CE keys were stored in fs keyring then
// they will be lost after unmount. Attempt to re-install them.
if (IsFbeEnabled() && android::vold::isFsKeyringSupported()) {
if (!try_reload_ce_keys()) return false;
}
fscrypt_init_user0_done = true; fscrypt_init_user0_done = true;
return true; return true;
} }
@ -683,30 +653,34 @@ static void drop_caches_if_needed() {
} }
} }
static bool evict_ce_key(userid_t user_id) { // Evicts all the user's keys of one type from all volumes (internal and adoptable).
// This evicts either CE keys or DE keys, depending on which map is passed.
static bool evict_user_keys(std::map<userid_t, UserPolicies>& policy_map, userid_t user_id) {
bool success = true; bool success = true;
EncryptionPolicy policy; auto it = policy_map.find(user_id);
// If we haven't loaded the CE key, no need to evict it. if (it != policy_map.end()) {
if (lookup_policy(s_ce_policies, user_id, &policy)) { const UserPolicies& policies = it->second;
success &= android::vold::evictKey(DATA_MNT_POINT, policy); success &= android::vold::evictKey(BuildDataPath(""), policies.internal);
for (const auto& [volume_uuid, policy] : policies.adoptable) {
success &= android::vold::evictKey(BuildDataPath(volume_uuid), policy);
}
policy_map.erase(it);
drop_caches_if_needed(); drop_caches_if_needed();
} }
s_ce_policies.erase(user_id);
s_new_ce_keys.erase(user_id);
return success; return success;
} }
// Evicts and destroys all CE and DE keys for a user. This is called when the user is removed.
bool fscrypt_destroy_user_key(userid_t user_id) { bool fscrypt_destroy_user_key(userid_t user_id) {
LOG(DEBUG) << "fscrypt_destroy_user_key(" << user_id << ")"; LOG(DEBUG) << "fscrypt_destroy_user_key(" << user_id << ")";
if (!IsFbeEnabled()) { if (!IsFbeEnabled()) {
return true; return true;
} }
bool success = true; bool success = true;
success &= evict_ce_key(user_id);
EncryptionPolicy de_policy; success &= evict_user_keys(s_ce_policies, user_id);
success &= lookup_policy(s_de_policies, user_id, &de_policy) && success &= evict_user_keys(s_de_policies, user_id);
android::vold::evictKey(DATA_MNT_POINT, de_policy);
s_de_policies.erase(user_id);
if (!s_ephemeral_users.erase(user_id)) { if (!s_ephemeral_users.erase(user_id)) {
auto ce_path = get_ce_key_directory_path(user_id); auto ce_path = get_ce_key_directory_path(user_id);
if (!s_new_ce_keys.erase(user_id)) { if (!s_new_ce_keys.erase(user_id)) {
@ -759,7 +733,7 @@ static std::string volume_secdiscardable_path(const std::string& volume_uuid) {
} }
static bool read_or_create_volkey(const std::string& misc_path, const std::string& volume_uuid, static bool read_or_create_volkey(const std::string& misc_path, const std::string& volume_uuid,
EncryptionPolicy* policy) { UserPolicies& user_policies, EncryptionPolicy* policy) {
auto secdiscardable_path = volume_secdiscardable_path(volume_uuid); auto secdiscardable_path = volume_secdiscardable_path(volume_uuid);
std::string secdiscardable_hash; std::string secdiscardable_hash;
if (android::vold::pathExists(secdiscardable_path)) { if (android::vold::pathExists(secdiscardable_path)) {
@ -780,6 +754,7 @@ static bool read_or_create_volkey(const std::string& misc_path, const std::strin
if (!retrieveOrGenerateKey(key_path, key_path + "_tmp", auth, makeGen(options), &key)) if (!retrieveOrGenerateKey(key_path, key_path + "_tmp", auth, makeGen(options), &key))
return false; return false;
if (!install_storage_key(BuildDataPath(volume_uuid), options, key, policy)) return false; if (!install_storage_key(BuildDataPath(volume_uuid), options, key, policy)) return false;
user_policies.adoptable[volume_uuid] = *policy;
return true; return true;
} }
@ -887,37 +862,38 @@ void fscrypt_deferred_fixate_ce_keys() {
std::vector<int> fscrypt_get_unlocked_users() { std::vector<int> fscrypt_get_unlocked_users() {
std::vector<int> user_ids; std::vector<int> user_ids;
for (const auto& it : s_ce_policies) { for (const auto& [user_id, user_policies] : s_ce_policies) {
user_ids.push_back(it.first); user_ids.push_back(user_id);
} }
return user_ids; return user_ids;
} }
// TODO: rename to 'install' for consistency, and take flags to know which keys to install // Unlocks internal CE storage for the given user. This only unlocks internal storage, since
// fscrypt_prepare_user_storage() has to be called for each adoptable storage volume anyway (since
// the volume might have been absent when the user was created), and that handles the unlocking.
bool fscrypt_unlock_user_key(userid_t user_id, int serial, const std::string& secret_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; LOG(DEBUG) << "fscrypt_unlock_user_key " << user_id << " serial=" << serial;
if (IsFbeEnabled()) { if (!IsFbeEnabled()) return true;
if (s_ce_policies.count(user_id) != 0) { if (s_ce_policies.count(user_id) != 0) {
LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id; LOG(WARNING) << "Tried to unlock already-unlocked key for user " << user_id;
return true; return true;
} }
auto auth = authentication_from_hex(secret_hex); auto auth = authentication_from_hex(secret_hex);
if (!auth) return false; if (!auth) return false;
if (!read_and_install_user_ce_key(user_id, *auth)) { KeyBuffer ce_key;
LOG(ERROR) << "Couldn't read key for " << user_id; if (!read_and_fixate_user_ce_key(user_id, *auth, &ce_key)) return false;
return false; EncryptionPolicy ce_policy;
} if (!install_storage_key(DATA_MNT_POINT, s_data_options, ce_key, &ce_policy)) return false;
} s_ce_policies[user_id].internal = ce_policy;
LOG(DEBUG) << "Installed ce key for user " << user_id;
return true; return true;
} }
// TODO: rename to 'evict' for consistency // Locks CE storage for the given user. This locks both internal and adoptable storage.
bool fscrypt_lock_user_key(userid_t user_id) { bool fscrypt_lock_user_key(userid_t user_id) {
LOG(DEBUG) << "fscrypt_lock_user_key " << user_id; LOG(DEBUG) << "fscrypt_lock_user_key " << user_id;
if (IsFbeEnabled()) { if (!IsFbeEnabled()) return true;
return evict_ce_key(user_id); return evict_user_keys(s_ce_policies, user_id);
}
return true;
} }
static bool prepare_subdirs(const std::string& action, const std::string& volume_uuid, static bool prepare_subdirs(const std::string& action, const std::string& volume_uuid,
@ -967,14 +943,18 @@ bool fscrypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_
auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id); auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id);
if (IsFbeEnabled()) { if (IsFbeEnabled()) {
if (volume_uuid.empty()) { auto it = s_de_policies.find(user_id);
if (!lookup_policy(s_de_policies, user_id, &de_policy)) { if (it == s_de_policies.end()) {
LOG(ERROR) << "Cannot find DE policy for user " << user_id; LOG(ERROR) << "Cannot find DE policy for user " << user_id;
return false; return false;
} }
UserPolicies& user_de_policies = it->second;
if (volume_uuid.empty()) {
de_policy = user_de_policies.internal;
} else { } else {
auto misc_de_empty_volume_path = android::vold::BuildDataMiscDePath("", user_id); auto misc_de_empty_volume_path = android::vold::BuildDataMiscDePath("", user_id);
if (!read_or_create_volkey(misc_de_empty_volume_path, volume_uuid, &de_policy)) { if (!read_or_create_volkey(misc_de_empty_volume_path, volume_uuid, user_de_policies,
&de_policy)) {
return false; return false;
} }
} }
@ -1011,14 +991,18 @@ bool fscrypt_prepare_user_storage(const std::string& volume_uuid, userid_t user_
auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id); auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id);
if (IsFbeEnabled()) { if (IsFbeEnabled()) {
if (volume_uuid.empty()) { auto it = s_ce_policies.find(user_id);
if (!lookup_policy(s_ce_policies, user_id, &ce_policy)) { if (it == s_ce_policies.end()) {
LOG(ERROR) << "Cannot find CE policy for user " << user_id; LOG(ERROR) << "Cannot find CE policy for user " << user_id;
return false; return false;
} }
UserPolicies& user_ce_policies = it->second;
if (volume_uuid.empty()) {
ce_policy = user_ce_policies.internal;
} else { } else {
auto misc_ce_empty_volume_path = android::vold::BuildDataMiscCePath("", user_id); auto misc_ce_empty_volume_path = android::vold::BuildDataMiscCePath("", user_id);
if (!read_or_create_volkey(misc_ce_empty_volume_path, volume_uuid, &ce_policy)) { if (!read_or_create_volkey(misc_ce_empty_volume_path, volume_uuid, user_ce_policies,
&ce_policy)) {
return false; return false;
} }
} }
@ -1148,12 +1132,27 @@ static bool destroy_volume_keys(const std::string& directory_path, const std::st
return res; return res;
} }
static void erase_volume_policies(std::map<userid_t, UserPolicies>& policy_map,
const std::string& volume_uuid) {
for (auto& [user_id, user_policies] : policy_map) {
user_policies.adoptable.erase(volume_uuid);
}
}
// Destroys all CE and DE keys for an adoptable storage volume that is permanently going away.
// Requires VolumeManager::mCryptLock.
bool fscrypt_destroy_volume_keys(const std::string& volume_uuid) { bool fscrypt_destroy_volume_keys(const std::string& volume_uuid) {
if (!IsFbeEnabled()) return true;
bool res = true; bool res = true;
LOG(DEBUG) << "fscrypt_destroy_volume_keys for volume " << escape_empty(volume_uuid); LOG(DEBUG) << "fscrypt_destroy_volume_keys for volume " << escape_empty(volume_uuid);
auto secdiscardable_path = volume_secdiscardable_path(volume_uuid); auto secdiscardable_path = volume_secdiscardable_path(volume_uuid);
res &= android::vold::runSecdiscardSingle(secdiscardable_path); res &= android::vold::runSecdiscardSingle(secdiscardable_path);
res &= destroy_volume_keys("/data/misc_ce", volume_uuid); res &= destroy_volume_keys("/data/misc_ce", volume_uuid);
res &= destroy_volume_keys("/data/misc_de", volume_uuid); res &= destroy_volume_keys("/data/misc_de", volume_uuid);
// Drop the CE and DE policies stored in memory, as they are not needed anymore. Note that it's
// not necessary to also evict the corresponding keys from the kernel, as that happens
// automatically as a result of the volume being unmounted.
erase_volume_policies(s_ce_policies, volume_uuid);
erase_volume_policies(s_de_policies, volume_uuid);
return res; return res;
} }

125
KeyUtil.cpp
View file

@ -164,7 +164,7 @@ static bool fscryptKeyring(key_serial_t* device_keyring) {
return true; return true;
} }
// Add an encryption key of type "logon" to the global session keyring. // Add an encryption key to the legacy global session keyring.
static bool installKeyLegacy(const KeyBuffer& key, const std::string& raw_ref) { static bool installKeyLegacy(const KeyBuffer& key, const std::string& raw_ref) {
// Place fscrypt_key into automatically zeroing buffer. // Place fscrypt_key into automatically zeroing buffer.
KeyBuffer fsKeyBuffer(sizeof(fscrypt_key)); KeyBuffer fsKeyBuffer(sizeof(fscrypt_key));
@ -187,32 +187,6 @@ static bool installKeyLegacy(const KeyBuffer& key, const std::string& raw_ref) {
return true; return true;
} }
// Installs fscrypt-provisioning key into session level kernel keyring.
// This allows for the given key to be installed back into filesystem keyring.
// For more context see reloadKeyFromSessionKeyring.
static bool installProvisioningKey(const KeyBuffer& key, const std::string& ref,
const fscrypt_key_specifier& key_spec) {
key_serial_t device_keyring;
if (!fscryptKeyring(&device_keyring)) return false;
// Place fscrypt_provisioning_key_payload into automatically zeroing buffer.
KeyBuffer buf(sizeof(fscrypt_provisioning_key_payload) + key.size(), 0);
fscrypt_provisioning_key_payload& provisioning_key =
*reinterpret_cast<fscrypt_provisioning_key_payload*>(buf.data());
memcpy(provisioning_key.raw, key.data(), key.size());
provisioning_key.type = key_spec.type;
key_serial_t key_id = add_key("fscrypt-provisioning", ref.c_str(), (void*)&provisioning_key,
buf.size(), device_keyring);
if (key_id == -1) {
PLOG(ERROR) << "Failed to insert fscrypt-provisioning key for " << ref
<< " into session keyring";
return false;
}
LOG(DEBUG) << "Added fscrypt-provisioning key for " << ref << " to session keyring";
return true;
}
// Build a struct fscrypt_key_specifier for use in the key management ioctls. // Build a struct fscrypt_key_specifier for use in the key management ioctls.
static bool buildKeySpecifier(fscrypt_key_specifier* spec, const EncryptionPolicy& policy) { static bool buildKeySpecifier(fscrypt_key_specifier* spec, const EncryptionPolicy& policy) {
switch (policy.options.version) { switch (policy.options.version) {
@ -240,34 +214,6 @@ static bool buildKeySpecifier(fscrypt_key_specifier* spec, const EncryptionPolic
} }
} }
// Installs key into keyring of a filesystem mounted on |mountpoint|.
//
// It's callers responsibility to fill key specifier, and either arg->raw or arg->key_id.
//
// In case arg->key_spec.type equals to FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER
// arg->key_spec.u.identifier will be populated with raw key reference generated
// by kernel.
//
// For documentation on difference between arg->raw and arg->key_id see
// https://www.kernel.org/doc/html/latest/filesystems/fscrypt.html#fs-ioc-add-encryption-key
static bool installFsKeyringKey(const std::string& mountpoint, const EncryptionOptions& options,
fscrypt_add_key_arg* arg) {
if (options.use_hw_wrapped_key) arg->__flags |= __FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED;
android::base::unique_fd fd(open(mountpoint.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC));
if (fd == -1) {
PLOG(ERROR) << "Failed to open " << mountpoint << " to install key";
return false;
}
if (ioctl(fd, FS_IOC_ADD_ENCRYPTION_KEY, arg) != 0) {
PLOG(ERROR) << "Failed to install fscrypt key to " << mountpoint;
return false;
}
return true;
}
bool installKey(const std::string& mountpoint, const EncryptionOptions& options, bool installKey(const std::string& mountpoint, const EncryptionOptions& options,
const KeyBuffer& key, EncryptionPolicy* policy) { const KeyBuffer& key, EncryptionPolicy* policy) {
const std::lock_guard<std::mutex> lock(fscrypt_keyring_mutex); const std::lock_guard<std::mutex> lock(fscrypt_keyring_mutex);
@ -304,24 +250,33 @@ bool installKey(const std::string& mountpoint, const EncryptionOptions& options,
return false; return false;
} }
if (options.use_hw_wrapped_key) arg->__flags |= __FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED;
// Provide the raw key.
arg->raw_size = key.size(); arg->raw_size = key.size();
memcpy(arg->raw, key.data(), key.size()); memcpy(arg->raw, key.data(), key.size());
if (!installFsKeyringKey(mountpoint, options, arg)) return false; android::base::unique_fd fd(open(mountpoint.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC));
if (fd == -1) {
PLOG(ERROR) << "Failed to open " << mountpoint << " to install key";
return false;
}
if (ioctl(fd, FS_IOC_ADD_ENCRYPTION_KEY, arg) != 0) {
PLOG(ERROR) << "Failed to install fscrypt key to " << mountpoint;
return false;
}
if (arg->key_spec.type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) { if (arg->key_spec.type == FSCRYPT_KEY_SPEC_TYPE_IDENTIFIER) {
// Retrieve the key identifier that the kernel computed. // Retrieve the key identifier that the kernel computed.
policy->key_raw_ref = policy->key_raw_ref =
std::string((char*)arg->key_spec.u.identifier, FSCRYPT_KEY_IDENTIFIER_SIZE); std::string((char*)arg->key_spec.u.identifier, FSCRYPT_KEY_IDENTIFIER_SIZE);
} }
std::string ref = keyrefstring(policy->key_raw_ref); LOG(DEBUG) << "Installed fscrypt key with ref " << keyrefstring(policy->key_raw_ref) << " to "
LOG(DEBUG) << "Installed fscrypt key with ref " << ref << " to " << mountpoint; << mountpoint;
if (!installProvisioningKey(key, ref, arg->key_spec)) return false;
return true; return true;
} }
// Remove an encryption key of type "logon" from the global session keyring. // Remove an encryption key from the legacy global session keyring.
static bool evictKeyLegacy(const std::string& raw_ref) { static bool evictKeyLegacy(const std::string& raw_ref) {
key_serial_t device_keyring; key_serial_t device_keyring;
if (!fscryptKeyring(&device_keyring)) return false; if (!fscryptKeyring(&device_keyring)) return false;
@ -344,26 +299,6 @@ static bool evictKeyLegacy(const std::string& raw_ref) {
return success; return success;
} }
static bool evictProvisioningKey(const std::string& ref) {
key_serial_t device_keyring;
if (!fscryptKeyring(&device_keyring)) {
return false;
}
auto key_serial = keyctl_search(device_keyring, "fscrypt-provisioning", ref.c_str(), 0);
if (key_serial == -1 && errno != ENOKEY) {
PLOG(ERROR) << "Error searching session keyring for fscrypt-provisioning key for " << ref;
return false;
}
if (key_serial != -1 && keyctl_unlink(key_serial, device_keyring) != 0) {
PLOG(ERROR) << "Failed to unlink fscrypt-provisioning key for " << ref
<< " from session keyring";
return false;
}
return true;
}
static void waitForBusyFiles(const struct fscrypt_key_specifier key_spec, const std::string ref, static void waitForBusyFiles(const struct fscrypt_key_specifier key_spec, const std::string ref,
const std::string mountpoint) { const std::string mountpoint) {
android::base::unique_fd fd(open(mountpoint.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC)); android::base::unique_fd fd(open(mountpoint.c_str(), O_RDONLY | O_DIRECTORY | O_CLOEXEC));
@ -462,8 +397,6 @@ bool evictKey(const std::string& mountpoint, const EncryptionPolicy& policy) {
std::thread busyFilesThread(waitForBusyFiles, arg.key_spec, ref, mountpoint); std::thread busyFilesThread(waitForBusyFiles, arg.key_spec, ref, mountpoint);
busyFilesThread.detach(); busyFilesThread.detach();
} }
if (!evictProvisioningKey(ref)) return false;
return true; return true;
} }
@ -485,31 +418,5 @@ bool retrieveOrGenerateKey(const std::string& key_path, const std::string& tmp_p
return true; return true;
} }
bool reloadKeyFromSessionKeyring(const std::string& mountpoint, const EncryptionPolicy& policy) {
key_serial_t device_keyring;
if (!fscryptKeyring(&device_keyring)) {
return false;
}
std::string ref = keyrefstring(policy.key_raw_ref);
auto key_serial = keyctl_search(device_keyring, "fscrypt-provisioning", ref.c_str(), 0);
if (key_serial == -1) {
PLOG(ERROR) << "Failed to find fscrypt-provisioning key for " << ref
<< " in session keyring";
return false;
}
LOG(DEBUG) << "Installing fscrypt-provisioning key for " << ref << " back into " << mountpoint
<< " fs-keyring";
struct fscrypt_add_key_arg arg;
memset(&arg, 0, sizeof(arg));
if (!buildKeySpecifier(&arg.key_spec, policy)) return false;
arg.key_id = key_serial;
if (!installFsKeyringKey(mountpoint, policy.options, &arg)) return false;
return true;
}
} // namespace vold } // namespace vold
} // namespace android } // namespace android

18
KeyUtil.h
View file

@ -49,16 +49,11 @@ bool isFsKeyringSupported(void);
// on the specified filesystem using the specified encryption policy version. // on the specified filesystem using the specified encryption policy version.
// //
// For v1 policies, we use FS_IOC_ADD_ENCRYPTION_KEY if the kernel supports it. // For v1 policies, we use FS_IOC_ADD_ENCRYPTION_KEY if the kernel supports it.
// Otherwise we add the key to the global session keyring as a "logon" key. // Otherwise we add the key to the legacy global session keyring.
// //
// For v2 policies, we always use FS_IOC_ADD_ENCRYPTION_KEY; it's the only way // For v2 policies, we always use FS_IOC_ADD_ENCRYPTION_KEY; it's the only way
// the kernel supports. // the kernel supports.
// //
// If kernel supports FS_IOC_ADD_ENCRYPTION_KEY, also installs key of
// fscrypt-provisioning type to the global session keyring. This makes it
// possible to unmount and then remount mountpoint without losing the file-based
// key.
//
// Returns %true on success, %false on failure. On success also sets *policy // Returns %true on success, %false on failure. On success also sets *policy
// to the EncryptionPolicy used to refer to this key. // to the EncryptionPolicy used to refer to this key.
bool installKey(const std::string& mountpoint, const android::fscrypt::EncryptionOptions& options, bool installKey(const std::string& mountpoint, const android::fscrypt::EncryptionOptions& options,
@ -66,10 +61,10 @@ bool installKey(const std::string& mountpoint, const android::fscrypt::Encryptio
// Evict a file-based encryption key from the kernel. // Evict a file-based encryption key from the kernel.
// //
// This undoes the effect of installKey(). // We use FS_IOC_REMOVE_ENCRYPTION_KEY if the kernel supports it. Otherwise we
// remove the key from the legacy global session keyring.
// //
// If the kernel doesn't support the filesystem-level keyring, the caller is // In the latter case, the caller is responsible for dropping caches.
// responsible for dropping caches.
bool evictKey(const std::string& mountpoint, const android::fscrypt::EncryptionPolicy& policy); bool evictKey(const std::string& mountpoint, const android::fscrypt::EncryptionPolicy& policy);
// Retrieves the key from the named directory, or generates it if it doesn't // Retrieves the key from the named directory, or generates it if it doesn't
@ -78,11 +73,6 @@ bool retrieveOrGenerateKey(const std::string& key_path, const std::string& tmp_p
const KeyAuthentication& key_authentication, const KeyGeneration& gen, const KeyAuthentication& key_authentication, const KeyGeneration& gen,
KeyBuffer* key); KeyBuffer* key);
// Re-installs a file-based encryption key of fscrypt-provisioning type from the
// global session keyring back into fs keyring of the mountpoint.
bool reloadKeyFromSessionKeyring(const std::string& mountpoint,
const android::fscrypt::EncryptionPolicy& policy);
} // namespace vold } // namespace vold
} // namespace android } // namespace android

14
VoldNativeService.cpp
View file

@ -256,9 +256,19 @@ binder::Status VoldNativeService::forgetPartition(const std::string& partGuid,
ENFORCE_SYSTEM_OR_ROOT; ENFORCE_SYSTEM_OR_ROOT;
CHECK_ARGUMENT_HEX(partGuid); CHECK_ARGUMENT_HEX(partGuid);
CHECK_ARGUMENT_HEX(fsUuid); CHECK_ARGUMENT_HEX(fsUuid);
ACQUIRE_LOCK; bool success = true;
return translate(VolumeManager::Instance()->forgetPartition(partGuid, fsUuid)); {
ACQUIRE_LOCK;
success &= VolumeManager::Instance()->forgetPartition(partGuid, fsUuid);
}
{
ACQUIRE_CRYPT_LOCK;
success &= fscrypt_destroy_volume_keys(fsUuid);
}
return translateBool(success);
} }
binder::Status VoldNativeService::mount( binder::Status VoldNativeService::mount(

14
VolumeManager.cpp
View file

@ -349,25 +349,19 @@ void VolumeManager::listVolumes(android::vold::VolumeBase::Type type,
} }
} }
int VolumeManager::forgetPartition(const std::string& partGuid, const std::string& fsUuid) { bool VolumeManager::forgetPartition(const std::string& partGuid, const std::string& fsUuid) {
std::string normalizedGuid; std::string normalizedGuid;
if (android::vold::NormalizeHex(partGuid, normalizedGuid)) { if (android::vold::NormalizeHex(partGuid, normalizedGuid)) {
LOG(WARNING) << "Invalid GUID " << partGuid; LOG(WARNING) << "Invalid GUID " << partGuid;
return -1; return false;
} }
bool success = true;
std::string keyPath = android::vold::BuildKeyPath(normalizedGuid); std::string keyPath = android::vold::BuildKeyPath(normalizedGuid);
if (unlink(keyPath.c_str()) != 0) { if (unlink(keyPath.c_str()) != 0) {
LOG(ERROR) << "Failed to unlink " << keyPath; LOG(ERROR) << "Failed to unlink " << keyPath;
success = false; return false;
} }
if (IsFbeEnabled()) { return true;
if (!fscrypt_destroy_volume_keys(fsUuid)) {
success = false;
}
}
return success ? 0 : -1;
} }
void VolumeManager::destroyEmulatedVolumesForUser(userid_t userId) { void VolumeManager::destroyEmulatedVolumesForUser(userid_t userId) {

2
VolumeManager.h
View file

@ -106,7 +106,7 @@ class VolumeManager {
userid_t getSharedStorageUser(userid_t userId); userid_t getSharedStorageUser(userid_t userId);
int forgetPartition(const std::string& partGuid, const std::string& fsUuid); bool forgetPartition(const std::string& partGuid, const std::string& fsUuid);
int onUserAdded(userid_t userId, int userSerialNumber, userid_t cloneParentUserId); int onUserAdded(userid_t userId, int userSerialNumber, userid_t cloneParentUserId);
int onUserRemoved(userid_t userId); int onUserRemoved(userid_t userId);