Revert "fskeyring & userspace reboot: support CE keys"
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 1c6731c64972 (https://r.android.com/1254615)
with various conflicts resolved.
Bug: 292469129
Change-Id: If530edaf7c1566dd3bd8b1322f935f38a2e66beb
Merged-In: If530edaf7c1566dd3bd8b1322f935f38a2e66beb
(cherry picked from commit 2b97a88ba4f29b98efd8b31ce6f2f36a2334acaf)
diff --git a/FsCrypt.cpp b/FsCrypt.cpp
index ecb3c81..45b062d 100644
--- a/FsCrypt.cpp
+++ b/FsCrypt.cpp
@@ -482,17 +482,6 @@
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 @@
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;
}
diff --git a/KeyUtil.cpp b/KeyUtil.cpp
index 5a8b550..9e8920d 100644
--- a/KeyUtil.cpp
+++ b/KeyUtil.cpp
@@ -164,7 +164,7 @@
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 @@
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 @@
}
}
-// 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 @@
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 @@
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 @@
std::thread busyFilesThread(waitForBusyFiles, arg.key_spec, ref, mountpoint);
busyFilesThread.detach();
}
-
- if (!evictProvisioningKey(ref)) return false;
return true;
}
@@ -485,31 +418,5 @@
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
diff --git a/KeyUtil.h b/KeyUtil.h
index 5940b8a..17a234e 100644
--- a/KeyUtil.h
+++ b/KeyUtil.h
@@ -49,16 +49,11 @@
// 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 @@
// 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 @@
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