Merge "fskeyring & userspace reboot: support CE keys" into rvc-dev
diff --git a/FsCrypt.cpp b/FsCrypt.cpp
index d43bc08..d8af6f4 100644
--- a/FsCrypt.cpp
+++ b/FsCrypt.cpp
@@ -378,6 +378,17 @@
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() {
LOG(INFO) << "fscrypt_initialize_systemwide_keys";
@@ -444,6 +455,13 @@
fscrypt_unlock_user_key(0, 0, "!", "!");
}
+ // 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 (fscrypt_is_native() && android::vold::isFsKeyringSupported()) {
+ if (!try_reload_ce_keys()) return false;
+ }
+
return true;
}
diff --git a/KeyUtil.cpp b/KeyUtil.cpp
index 6200c42..3359699 100644
--- a/KeyUtil.cpp
+++ b/KeyUtil.cpp
@@ -155,7 +155,7 @@
return true;
}
-// Add an encryption key to the legacy global session keyring.
+// Add an encryption key of type "logon" to the 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));
@@ -178,6 +178,32 @@
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) {
@@ -205,6 +231,34 @@
}
}
+// 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_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) {
policy->options = options;
@@ -240,33 +294,24 @@
return false;
}
- if (options.use_hw_wrapped_key) arg->flags |= FSCRYPT_ADD_KEY_FLAG_WRAPPED;
- // Provide the raw key.
arg->raw_size = key.size();
memcpy(arg->raw, key.data(), key.size());
- 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 (!installFsKeyringKey(mountpoint, options, arg)) 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);
}
- LOG(DEBUG) << "Installed fscrypt key with ref " << keyrefstring(policy->key_raw_ref) << " to "
- << mountpoint;
+ 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;
return true;
}
-// Remove an encryption key from the legacy global session keyring.
+// Remove an encryption key of type "logon" from the global session keyring.
static bool evictKeyLegacy(const std::string& raw_ref) {
key_serial_t device_keyring;
if (!fscryptKeyring(&device_keyring)) return false;
@@ -289,6 +334,26 @@
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;
+}
+
bool evictKey(const std::string& mountpoint, const EncryptionPolicy& policy) {
if (policy.options.version == 1 && !isFsKeyringSupported()) {
return evictKeyLegacy(policy.key_raw_ref);
@@ -322,6 +387,8 @@
LOG(ERROR) << "Files still open after removing key with ref " << ref
<< ". These files were not locked!";
}
+
+ if (!evictProvisioningKey(ref)) return false;
return true;
}
@@ -343,5 +410,31 @@
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 dcb1dc7..23278c1 100644
--- a/KeyUtil.h
+++ b/KeyUtil.h
@@ -51,11 +51,16 @@
// 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 legacy global session keyring.
+// Otherwise we add the key to the global session keyring as a "logon" key.
//
// 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 EncryptionOptions& options,
@@ -63,16 +68,20 @@
// Evict a file-based encryption key from the kernel.
//
-// We use FS_IOC_REMOVE_ENCRYPTION_KEY if the kernel supports it. Otherwise we
-// remove the key from the legacy global session keyring.
+// This undoes the effect of installKey().
//
-// In the latter case, the caller is responsible for dropping caches.
+// If the kernel doesn't support the filesystem-level keyring, the caller is
+// responsible for dropping caches.
bool evictKey(const std::string& mountpoint, const EncryptionPolicy& policy);
bool retrieveOrGenerateKey(const std::string& key_path, const std::string& tmp_path,
const KeyAuthentication& key_authentication, const KeyGeneration& gen,
KeyBuffer* key, bool keepOld = true);
+// 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 EncryptionPolicy& policy);
+
} // namespace vold
} // namespace android
diff --git a/fscrypt_uapi.h b/fscrypt_uapi.h
index 08592e0..3cda96e 100644
--- a/fscrypt_uapi.h
+++ b/fscrypt_uapi.h
@@ -9,11 +9,19 @@
struct sys_fscrypt_add_key_arg {
struct fscrypt_key_specifier key_spec;
__u32 raw_size;
- __u32 __reserved[8];
+ __u32 key_id;
+ __u32 __reserved[7];
__u32 flags;
__u8 raw[];
};
+struct sys_fscrypt_provisioning_key_payload {
+ __u32 type;
+ __u32 __reserved;
+ __u8 raw[];
+};
+
#define fscrypt_add_key_arg sys_fscrypt_add_key_arg
+#define fscrypt_provisioning_key_payload sys_fscrypt_provisioning_key_payload
#endif //_UAPI_LINUX_FSCRYPT_VOLD_H