session-ios/SignalServiceKit/src/Storage/OWSStorage.m
2018-02-09 10:31:29 -05:00

700 lines
22 KiB
Objective-C

//
// Copyright (c) 2018 Open Whisper Systems. All rights reserved.
//
#import "OWSStorage.h"
#import "AppContext.h"
#import "NSData+Base64.h"
#import "NSNotificationCenter+OWS.h"
#import "OWSFileSystem.h"
#import "OWSStorage+Subclass.h"
#import "TSAttachmentStream.h"
#import "TSStorageManager.h"
#import <Curve25519Kit/Randomness.h>
#import <SAMKeychain/SAMKeychain.h>
#import <YapDatabase/YapDatabase.h>
#import <YapDatabase/YapDatabaseCryptoUtils.h>
NS_ASSUME_NONNULL_BEGIN
NSString *const StorageIsReadyNotification = @"StorageIsReadyNotification";
NSString *const OWSStorageExceptionName_DatabasePasswordInaccessibleWhileBackgrounded
= @"OWSStorageExceptionName_DatabasePasswordInaccessibleWhileBackgrounded";
NSString *const OWSStorageExceptionName_DatabasePasswordUnwritable
= @"OWSStorageExceptionName_DatabasePasswordUnwritable";
NSString *const OWSStorageExceptionName_NoDatabase = @"OWSStorageExceptionName_NoDatabase";
NSString *const OWSResetStorageNotification = @"OWSResetStorageNotification";
static NSString *keychainService = @"TSKeyChainService";
static NSString *keychainDBLegacyPassphrase = @"TSDatabasePass";
static NSString *keychainDBCipherKeySpec = @"OWSDatabaseCipherKeySpec";
const NSUInteger kDatabasePasswordLength = 30;
typedef NSData *_Nullable (^LoadDatabaseMetadataBlock)(NSError **_Nullable);
typedef NSData *_Nullable (^CreateDatabaseMetadataBlock)(void);
#pragma mark -
@interface YapDatabaseConnection ()
- (id)initWithDatabase:(YapDatabase *)database;
@end
#pragma mark -
@implementation OWSDatabaseConnection
- (id)initWithDatabase:(YapDatabase *)database delegate:(id<OWSDatabaseConnectionDelegate>)delegate
{
self = [super initWithDatabase:database];
if (!self) {
return self;
}
OWSAssert(delegate);
_delegate = delegate;
return self;
}
// Assert that the database is in a ready state (specifically that any sync database
// view registrations have completed and any async registrations have been started)
// before creating write transactions.
//
// Creating write transactions before the _sync_ database views are registered
// causes YapDatabase to rebuild all of our database views, which is catastrophic.
// Specifically, it causes YDB's "view version" checks to fail.
- (void)readWriteWithBlock:(void (^)(YapDatabaseReadWriteTransaction *transaction))block
{
id<OWSDatabaseConnectionDelegate> delegate = self.delegate;
OWSAssert(delegate);
OWSAssert(delegate.areAllRegistrationsComplete || self.canWriteBeforeStorageReady);
[super readWriteWithBlock:block];
}
- (void)asyncReadWriteWithBlock:(void (^)(YapDatabaseReadWriteTransaction *transaction))block
{
[self asyncReadWriteWithBlock:block completionQueue:NULL completionBlock:NULL];
}
- (void)asyncReadWriteWithBlock:(void (^)(YapDatabaseReadWriteTransaction *transaction))block
completionBlock:(nullable dispatch_block_t)completionBlock
{
[self asyncReadWriteWithBlock:block completionQueue:NULL completionBlock:completionBlock];
}
- (void)asyncReadWriteWithBlock:(void (^)(YapDatabaseReadWriteTransaction *transaction))block
completionQueue:(nullable dispatch_queue_t)completionQueue
completionBlock:(nullable dispatch_block_t)completionBlock
{
id<OWSDatabaseConnectionDelegate> delegate = self.delegate;
OWSAssert(delegate);
OWSAssert(delegate.areAllRegistrationsComplete || self.canWriteBeforeStorageReady);
[super asyncReadWriteWithBlock:block completionQueue:completionQueue completionBlock:completionBlock];
}
@end
#pragma mark -
// This class is only used in DEBUG builds.
@interface YapDatabase ()
- (void)addConnection:(YapDatabaseConnection *)connection;
- (YapDatabaseConnection *)registrationConnection;
@end
#pragma mark -
@interface OWSDatabase : YapDatabase
@property (atomic, weak) id<OWSDatabaseConnectionDelegate> delegate;
@property (atomic, nullable) YapDatabaseConnection *registrationConnectionCached;
- (instancetype)init NS_UNAVAILABLE;
- (id)initWithPath:(NSString *)inPath
serializer:(nullable YapDatabaseSerializer)inSerializer
deserializer:(YapDatabaseDeserializer)inDeserializer
options:(YapDatabaseOptions *)inOptions
delegate:(id<OWSDatabaseConnectionDelegate>)delegate NS_DESIGNATED_INITIALIZER;
@end
#pragma mark -
@implementation OWSDatabase
- (id)initWithPath:(NSString *)inPath
serializer:(nullable YapDatabaseSerializer)inSerializer
deserializer:(YapDatabaseDeserializer)inDeserializer
options:(YapDatabaseOptions *)inOptions
delegate:(id<OWSDatabaseConnectionDelegate>)delegate
{
self = [super initWithPath:inPath serializer:inSerializer deserializer:inDeserializer options:inOptions];
if (!self) {
return self;
}
OWSAssert(delegate);
_delegate = delegate;
return self;
}
// This clobbers the superclass implementation to include asserts which
// ensure that the database is in a ready state before creating write transactions.
//
// See comments in OWSDatabaseConnection.
- (YapDatabaseConnection *)newConnection
{
id<OWSDatabaseConnectionDelegate> delegate = self.delegate;
OWSAssert(delegate);
OWSDatabaseConnection *connection = [[OWSDatabaseConnection alloc] initWithDatabase:self delegate:delegate];
[self addConnection:connection];
return connection;
}
- (YapDatabaseConnection *)registrationConnection
{
@synchronized(self)
{
if (!self.registrationConnectionCached) {
YapDatabaseConnection *connection = [super registrationConnection];
#ifdef DEBUG
// Flag the registration connection as such.
OWSAssert([connection isKindOfClass:[OWSDatabaseConnection class]]);
((OWSDatabaseConnection *)connection).canWriteBeforeStorageReady = YES;
#endif
self.registrationConnectionCached = connection;
}
return self.registrationConnectionCached;
}
}
@end
#pragma mark -
@interface OWSUnknownDBObject : NSObject <NSCoding>
@end
#pragma mark -
/**
* A default object to return when we can't deserialize an object from YapDB. This can prevent crashes when
* old objects linger after their definition file is removed. The danger is that, the objects can lay in wait
* until the next time a DB extension is added and we necessarily enumerate the entire DB.
*/
@implementation OWSUnknownDBObject
- (nullable instancetype)initWithCoder:(NSCoder *)aDecoder
{
return nil;
}
- (void)encodeWithCoder:(NSCoder *)aCoder
{
}
@end
#pragma mark -
@interface OWSUnarchiverDelegate : NSObject <NSKeyedUnarchiverDelegate>
@end
#pragma mark -
@implementation OWSUnarchiverDelegate
- (nullable Class)unarchiver:(NSKeyedUnarchiver *)unarchiver
cannotDecodeObjectOfClassName:(NSString *)name
originalClasses:(NSArray<NSString *> *)classNames
{
DDLogError(@"%@ Could not decode object: %@", self.logTag, name);
OWSProdError([OWSAnalyticsEvents storageErrorCouldNotDecodeClass]);
return [OWSUnknownDBObject class];
}
@end
#pragma mark -
@interface OWSStorage () <OWSDatabaseConnectionDelegate>
@property (atomic, nullable) YapDatabase *database;
@end
#pragma mark -
@implementation OWSStorage
- (instancetype)initStorage
{
self = [super init];
if (self) {
if (![self tryToLoadDatabase]) {
// Failing to load the database is catastrophic.
//
// The best we can try to do is to discard the current database
// and behave like a clean install.
OWSFail(@"%@ Could not load database", self.logTag);
OWSProdCritical([OWSAnalyticsEvents storageErrorCouldNotLoadDatabase]);
// Try to reset app by deleting all databases.
//
// TODO: Possibly clean up all app files.
// [OWSStorage deleteDatabaseFiles];
if (![self tryToLoadDatabase]) {
OWSFail(@"%@ Could not load database (second try)", self.logTag);
OWSProdCritical([OWSAnalyticsEvents storageErrorCouldNotLoadDatabaseSecondAttempt]);
// Sleep to give analytics events time to be delivered.
[NSThread sleepForTimeInterval:15.0f];
OWSRaiseException(OWSStorageExceptionName_NoDatabase, @"Failed to initialize database.");
}
}
[[NSNotificationCenter defaultCenter] addObserver:self
selector:@selector(resetStorage)
name:OWSResetStorageNotification
object:nil];
}
return self;
}
- (void)dealloc
{
[[NSNotificationCenter defaultCenter] removeObserver:self];
}
- (nullable id)dbNotificationObject
{
OWSAssert(self.database);
return self.database;
}
- (BOOL)areAsyncRegistrationsComplete
{
OWS_ABSTRACT_METHOD();
return NO;
}
- (BOOL)areSyncRegistrationsComplete
{
OWS_ABSTRACT_METHOD();
return NO;
}
- (BOOL)areAllRegistrationsComplete
{
return self.areSyncRegistrationsComplete && self.areAsyncRegistrationsComplete;
}
- (void)runSyncRegistrations
{
OWS_ABSTRACT_METHOD();
}
- (void)runAsyncRegistrationsWithCompletion:(void (^_Nonnull)(void))completion
{
OWS_ABSTRACT_METHOD();
}
+ (NSArray<OWSStorage *> *)allStorages
{
return @[
TSStorageManager.sharedManager,
];
}
+ (void)setupStorage
{
for (OWSStorage *storage in self.allStorages) {
[storage runSyncRegistrations];
}
for (OWSStorage *storage in self.allStorages) {
[storage runAsyncRegistrationsWithCompletion:^{
[self postRegistrationCompleteNotificationIfPossible];
((OWSDatabase *)storage.database).registrationConnectionCached = nil;
}];
}
}
- (YapDatabaseConnection *)registrationConnection
{
return self.database.registrationConnection;
}
+ (void)postRegistrationCompleteNotificationIfPossible
{
if (!self.isStorageReady) {
return;
}
static dispatch_once_t onceToken;
dispatch_once(&onceToken, ^{
[[NSNotificationCenter defaultCenter] postNotificationNameAsync:StorageIsReadyNotification
object:nil
userInfo:nil];
});
}
+ (BOOL)isStorageReady
{
for (OWSStorage *storage in self.allStorages) {
if (!storage.areAllRegistrationsComplete) {
return NO;
}
}
return YES;
}
- (BOOL)tryToLoadDatabase
{
YapDatabaseOptions *options = [[YapDatabaseOptions alloc] init];
options.corruptAction = YapDatabaseCorruptAction_Fail;
options.enableMultiProcessSupport = YES;
options.cipherKeySpecBlock = ^{
// Rather than compute this once and capture the value of the key
// in the closure, we prefer to fetch the key from the keychain multiple times
// in order to keep the key out of application memory.
NSData *databaseKeySpec = [self databaseKeySpec];
OWSAssert(databaseKeySpec.length == kSQLCipherKeySpecLength);
return databaseKeySpec;
};
// We leave a portion of the header decrypted so that iOS will recognize the file
// as a SQLite database. Otherwise, because the database lives in a shared data container,
// and our usage of sqlite's write-ahead logging retains a lock on the database, the OS
// would kill the app/share extension as soon as it is backgrounded.
options.cipherUnencryptedHeaderLength = kSqliteHeaderLength;
// If any of these asserts fails, we need to verify and update
// OWSDatabaseConverter which assumes the values of these options.
OWSAssert(options.cipherDefaultkdfIterNumber == 0);
OWSAssert(options.kdfIterNumber == 0);
OWSAssert(options.cipherPageSize == 0);
OWSAssert(options.pragmaPageSize == 0);
OWSAssert(options.pragmaJournalSizeLimit == 0);
OWSAssert(options.pragmaMMapSize == 0);
// Sanity checking elsewhere asserts we should only regenerate key specs when
// there is no existing database, so rather than lazily generate in the cipherKeySpecBlock
// we must ensure the keyspec exists before we create the database.
[self ensureDatabaseKeySpecExists];
OWSDatabase *database = [[OWSDatabase alloc] initWithPath:[self databaseFilePath]
serializer:nil
deserializer:[[self class] logOnFailureDeserializer]
options:options
delegate:self];
if (!database) {
return NO;
}
_database = database;
return YES;
}
/**
* NSCoding sometimes throws exceptions killing our app. We want to log that exception.
**/
+ (YapDatabaseDeserializer)logOnFailureDeserializer
{
OWSUnarchiverDelegate *unarchiverDelegate = [OWSUnarchiverDelegate new];
return ^id(NSString __unused *collection, NSString __unused *key, NSData *data) {
if (!data || data.length <= 0) {
return nil;
}
@try {
NSKeyedUnarchiver *unarchiver = [[NSKeyedUnarchiver alloc] initForReadingWithData:data];
unarchiver.delegate = unarchiverDelegate;
return [unarchiver decodeObjectForKey:@"root"];
} @catch (NSException *exception) {
// Sync log in case we bail.
OWSProdError([OWSAnalyticsEvents storageErrorDeserialization]);
@throw exception;
}
};
}
- (YapDatabaseConnection *)newDatabaseConnection
{
YapDatabaseConnection *dbConnection = self.database.newConnection;
OWSRaiseException(
@"OWSStorageExceptionName_CouldNotOpenConnection", @"Storage could not open new database connection.");
return dbConnection;
}
- (BOOL)registerExtension:(YapDatabaseExtension *)extension withName:(NSString *)extensionName
{
return [self.database registerExtension:extension withName:extensionName];
}
- (void)asyncRegisterExtension:(YapDatabaseExtension *)extension
withName:(NSString *)extensionName
{
[self.database asyncRegisterExtension:extension
withName:extensionName
completionBlock:^(BOOL ready) {
if (!ready) {
OWSFail(@"%@ asyncRegisterExtension failed: %@", self.logTag, extensionName);
} else {
DDLogVerbose(@"%@ asyncRegisterExtension succeeded: %@", self.logTag, extensionName);
}
}];
}
- (nullable id)registeredExtension:(NSString *)extensionName
{
return [self.database registeredExtension:extensionName];
}
#pragma mark - Password
+ (void)deleteDatabaseFiles
{
[OWSFileSystem deleteFile:[TSStorageManager databaseFilePath]];
}
- (void)deleteDatabaseFile
{
[OWSFileSystem deleteFile:[self databaseFilePath]];
}
- (void)resetStorage
{
self.database = nil;
[self deleteDatabaseFile];
}
+ (void)resetAllStorage
{
[[NSNotificationCenter defaultCenter] postNotificationName:OWSResetStorageNotification object:nil];
// This might be redundant but in the spirit of thoroughness...
[self deleteDatabaseFiles];
[self deleteDBKeys];
if (CurrentAppContext().isMainApp) {
[TSAttachmentStream deleteAttachments];
}
// TODO: Delete Profiles on Disk?
}
#pragma mark - Password
- (NSString *)databaseFilePath
{
OWS_ABSTRACT_METHOD();
return @"";
}
#pragma mark - Keychain
+ (BOOL)isDatabasePasswordAccessible
{
NSError *error;
NSData *cipherKeySpec = [self tryToLoadDatabaseCipherKeySpec:&error];
if (cipherKeySpec && !error) {
return YES;
}
if (error) {
DDLogWarn(@"Database key couldn't be accessed: %@", error.localizedDescription);
}
return NO;
}
+ (nullable NSData *)tryToLoadDatabaseLegacyPassphrase:(NSError **)errorHandle
{
return [self tryToLoadKeyChainValue:keychainDBLegacyPassphrase errorHandle:errorHandle];
}
+ (nullable NSData *)tryToLoadDatabaseCipherKeySpec:(NSError **)errorHandle
{
NSData *_Nullable data = [self tryToLoadKeyChainValue:keychainDBCipherKeySpec errorHandle:errorHandle];
OWSAssert(!data || data.length == kSQLCipherKeySpecLength);
return data;
}
+ (void)storeDatabaseCipherKeySpec:(NSData *)cipherKeySpecData
{
OWSAssert(cipherKeySpecData.length == kSQLCipherKeySpecLength);
[self storeKeyChainValue:cipherKeySpecData keychainKey:keychainDBCipherKeySpec];
}
+ (void)removeLegacyPassphrase
{
DDLogInfo(@"%@ removing legacy passphrase", self.logTag);
[SAMKeychain deletePasswordForService:keychainService account:keychainDBLegacyPassphrase];
}
- (void)ensureDatabaseKeySpecExists
{
NSError *error;
NSData *_Nullable keySpec = [[self class] tryToLoadDatabaseCipherKeySpec:&error];
if (error || (keySpec.length != kSQLCipherKeySpecLength)) {
// Because we use kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly,
// the keychain will be inaccessible after device restart until
// device is unlocked for the first time. If the app receives
// a push notification, we won't be able to access the keychain to
// process that notification, so we should just terminate by throwing
// an uncaught exception.
NSString *errorDescription = [NSString
stringWithFormat:@"CipherKeySpec inaccessible. New install or no unlock since device restart? Error: %@",
error];
if (CurrentAppContext().isMainApp) {
UIApplicationState applicationState = CurrentAppContext().mainApplicationState;
errorDescription =
[errorDescription stringByAppendingFormat:@", ApplicationState: %d", (int)applicationState];
}
DDLogError(@"%@ %@", self.logTag, errorDescription);
[DDLog flushLog];
if (CurrentAppContext().isMainApp) {
if (CurrentAppContext().isInBackground) {
// TODO: Rather than crash here, we should detect the situation earlier
// and exit gracefully - (in the app delegate?). See the `
// This is a last ditch effort to avoid blowing away the user's database.
[self raiseKeySpecInaccessibleExceptionWithErrorDescription:errorDescription];
}
} else {
[self raiseKeySpecInaccessibleExceptionWithErrorDescription:@"CipherKeySpec inaccessible; not main app."];
}
// At this point, either this is a new install so there's no existing password to retrieve
// or the keychain has become corrupt. Either way, we want to get back to a
// "known good state" and behave like a new install.
BOOL doesDBExist = [NSFileManager.defaultManager fileExistsAtPath:[self databaseFilePath]];
if (doesDBExist) {
OWSFail(@"%@ Could not load database metadata", self.logTag);
OWSProdCritical([OWSAnalyticsEvents storageErrorCouldNotLoadDatabaseSecondAttempt]);
}
// Try to reset app by deleting database.
[OWSStorage resetAllStorage];
keySpec = [Randomness generateRandomBytes:(int)kSQLCipherKeySpecLength];
[[self class] storeDatabaseCipherKeySpec:keySpec];
}
}
- (NSData *)databaseKeySpec
{
NSError *error;
NSData *_Nullable keySpec = [[self class] tryToLoadDatabaseCipherKeySpec:&error];
if (error) {
DDLogError(@"%@ failed to fetch databaseKeySpec with error: %@", self.logTag, error);
[self raiseKeySpecInaccessibleExceptionWithErrorDescription:@"CipherKeySpec inaccessible"];
}
if (keySpec.length != kSQLCipherKeySpecLength) {
DDLogError(@"%@ keyspec had length: %lu", self.logTag, (unsigned long)keySpec.length);
[self raiseKeySpecInaccessibleExceptionWithErrorDescription:@"CipherKeySpec invalid"];
}
return keySpec;
}
- (void)raiseKeySpecInaccessibleExceptionWithErrorDescription:(NSString *)errorDescription
{
OWSAssert(CurrentAppContext().isMainApp && CurrentAppContext().isInBackground);
// Sleep to give analytics events time to be delivered.
[NSThread sleepForTimeInterval:5.0f];
// Presumably this happened in response to a push notification. It's possible that the keychain is corrupted
// but it could also just be that the user hasn't yet unlocked their device since our password is
// kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly
OWSRaiseException(OWSStorageExceptionName_DatabasePasswordInaccessibleWhileBackgrounded, @"%@", errorDescription);
}
+ (void)deleteDBKeys
{
[SAMKeychain deletePasswordForService:keychainService account:keychainDBLegacyPassphrase];
[SAMKeychain deletePasswordForService:keychainService account:keychainDBCipherKeySpec];
}
- (unsigned long long)databaseFileSize
{
return [OWSFileSystem fileSizeOfPath:self.databaseFilePath].unsignedLongLongValue;
}
+ (nullable NSData *)tryToLoadKeyChainValue:(NSString *)keychainKey errorHandle:(NSError **)errorHandle
{
OWSAssert(keychainKey.length > 0);
OWSAssert(errorHandle);
return [SAMKeychain passwordDataForService:keychainService account:keychainKey error:errorHandle];
}
+ (void)storeKeyChainValue:(NSData *)data keychainKey:(NSString *)keychainKey
{
OWSAssert(keychainKey.length > 0);
OWSAssert(data.length > 0);
NSError *error;
[SAMKeychain setAccessibilityType:kSecAttrAccessibleAfterFirstUnlockThisDeviceOnly];
BOOL success = [SAMKeychain setPasswordData:data forService:keychainService account:keychainKey error:&error];
if (!success || error) {
OWSFail(@"%@ Could not store database metadata", self.logTag);
OWSProdCritical([OWSAnalyticsEvents storageErrorCouldNotStoreKeychainValue]);
// Sleep to give analytics events time to be delivered.
[NSThread sleepForTimeInterval:15.0f];
OWSRaiseException(
OWSStorageExceptionName_DatabasePasswordUnwritable, @"Setting keychain value failed with error: %@", error);
} else {
DDLogWarn(@"Successfully set new keychain value.");
}
}
@end
NS_ASSUME_NONNULL_END