tequilaOS/platform_system_vold
2
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

Revert "fskeyring & userspace reboot: support CE keys"

Browse source 
Userspace reboot turned out to be a dead end and is no longer supported.
Therefore, remove the code from vold that handled keeping CE storage
unlocked past the userdata filesystem being unmounted and mounted.

This is a revert of commit 1c6731c649 (https://r.android.com/1254615)
with various conflicts resolved.

Bug: 292469129
Change-Id: If530edaf7c1566dd3bd8b1322f935f38a2e66beb
Merged-In: If530edaf7c1566dd3bd8b1322f935f38a2e66beb
(cherry picked from commit 2b97a88ba4)
This commit is contained in:
Eric Biggers 2023-08-07 19:35:01 +00:00
parent 1eddb7cb6d
commit 01604fb13f
3 changed files with 20 additions and 141 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

18
FsCrypt.cpp
View file

@ -482,17 +482,6 @@ static bool load_all_de_keys() {
return true;
}
// Attempt to reinstall CE keys for users that we think are unlocked.
static bool try_reload_ce_keys() {
for (const auto& [user_id, user_policies] : s_ce_policies) {
if (!android::vold::reloadKeyFromSessionKeyring(DATA_MNT_POINT, user_policies.internal)) {
LOG(ERROR) << "Failed to load CE key from session keyring for user " << user_id;
return false;
}
}
return true;
}
bool fscrypt_initialize_systemwide_keys() {
LOG(INFO) << "fscrypt_initialize_systemwide_keys";
@ -621,13 +610,6 @@ bool fscrypt_init_user0() {
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;
return true;
}

125
KeyUtil.cpp
View file

@ -164,7 +164,7 @@ static bool fscryptKeyring(key_serial_t* device_keyring) {
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) {
// Place fscrypt_key into automatically zeroing buffer.
KeyBuffer fsKeyBuffer(sizeof(fscrypt_key));
@ -187,32 +187,6 @@ static bool installKeyLegacy(const KeyBuffer& key, const std::string& raw_ref) {
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.
static bool buildKeySpecifier(fscrypt_key_specifier* spec, const EncryptionPolicy& policy) {
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,
const KeyBuffer& key, EncryptionPolicy* policy) {
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;
}
if (options.use_hw_wrapped_key) arg->__flags |= __FSCRYPT_ADD_KEY_FLAG_HW_WRAPPED;
// Provide the raw key.
arg->raw_size = 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) {
// Retrieve the key identifier that the kernel computed.
policy->key_raw_ref =
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 " << ref << " to " << mountpoint;
if (!installProvisioningKey(key, ref, arg->key_spec)) return false;
LOG(DEBUG) << "Installed fscrypt key with ref " << keyrefstring(policy->key_raw_ref) << " to "
<< mountpoint;
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) {
key_serial_t device_keyring;
if (!fscryptKeyring(&device_keyring)) return false;
@ -344,26 +299,6 @@ static bool evictKeyLegacy(const std::string& raw_ref) {
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,
const std::string mountpoint) {
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);
busyFilesThread.detach();
}
if (!evictProvisioningKey(ref)) return false;
return true;
}
@ -485,31 +418,5 @@ bool retrieveOrGenerateKey(const std::string& key_path, const std::string& tmp_p
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 android

18
KeyUtil.h
View file

@ -49,16 +49,11 @@ bool isFsKeyringSupported(void);
// 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.
// 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
// 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
// to the EncryptionPolicy used to refer to this key.
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.
//
// 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
// responsible for dropping caches.
// In the latter case, the caller is responsible for dropping caches.
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
@ -78,11 +73,6 @@ bool retrieveOrGenerateKey(const std::string& key_path, const std::string& tmp_p
const KeyAuthentication& key_authentication, const KeyGeneration& gen,
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 android