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//
// OLMSession.m
// olm
//
// Created by Chris Ballinger on 4/8/16.
//
//
#import "OLMSession.h"
#import "OLMUtility.h"
#import "OLMAccount_Private.h"
#import "OLMSession_Private.h"
#include "olm/olm.h"
@implementation OLMSession
- (void) dealloc {
olm_clear_session(_session);
free(_session);
}
- (BOOL) initializeSessionMemory {
size_t size = olm_session_size();
_session = malloc(size);
NSParameterAssert(_session != nil);
if (!_session) {
return NO;
}
_session = olm_session(_session);
NSParameterAssert(_session != nil);
if (!_session) {
return NO;
}
return YES;
}
- (instancetype) init {
self = [super init];
if (!self) {
return nil;
}
BOOL success = [self initializeSessionMemory];
if (!success) {
return nil;
}
return self;
}
- (instancetype) initWithAccount:(OLMAccount*)account {
self = [self init];
if (!self) {
return nil;
}
NSParameterAssert(account != nil && account.account != NULL);
if (account == nil || account.account == NULL) {
return nil;
}
_account = account;
return self;
}
- (instancetype) initOutboundSessionWithAccount:(OLMAccount*)account theirIdentityKey:(NSString*)theirIdentityKey theirOneTimeKey:(NSString*)theirOneTimeKey {
self = [self initWithAccount:account];
if (!self) {
return nil;
}
NSMutableData *random = [OLMUtility randomBytesOfLength:olm_create_outbound_session_random_length(_session)];
NSData *idKey = [theirIdentityKey dataUsingEncoding:NSUTF8StringEncoding];
NSData *otKey = [theirOneTimeKey dataUsingEncoding:NSUTF8StringEncoding];
size_t result = olm_create_outbound_session(_session, account.account, idKey.bytes, idKey.length, otKey.bytes, otKey.length, random.mutableBytes, random.length);
if (result == olm_error()) {
const char *error = olm_session_last_error(_session);
NSAssert(NO, @"olm_create_outbound_session error: %s", error);
return nil;
}
return self;
}
- (instancetype) initInboundSessionWithAccount:(OLMAccount*)account oneTimeKeyMessage:(NSString*)oneTimeKeyMessage {
self = [self initWithAccount:account];
if (!self) {
return nil;
}
NSMutableData *otk = [NSMutableData dataWithData:[oneTimeKeyMessage dataUsingEncoding:NSUTF8StringEncoding]];
size_t result = olm_create_inbound_session(_session, account.account, otk.mutableBytes, oneTimeKeyMessage.length);
if (result == olm_error()) {
const char *error = olm_session_last_error(_session);
NSAssert(NO, @"olm_create_inbound_session error: %s", error);
return nil;
}
return self;
}
- (instancetype) initInboundSessionWithAccount:(OLMAccount*)account theirIdentityKey:(NSString*)theirIdentityKey oneTimeKeyMessage:(NSString*)oneTimeKeyMessage {
self = [self initWithAccount:account];
if (!self) {
return nil;
}
NSData *idKey = [theirIdentityKey dataUsingEncoding:NSUTF8StringEncoding];
NSMutableData *otk = [NSMutableData dataWithData:[oneTimeKeyMessage dataUsingEncoding:NSUTF8StringEncoding]];
size_t result = olm_create_inbound_session_from(_session, account.account, idKey.bytes, idKey.length, otk.mutableBytes, otk.length);
if (result == olm_error()) {
const char *error = olm_session_last_error(_session);
NSAssert(NO, @"olm_create_inbound_session_from error: %s", error);
return nil;
}
return self;
}
- (NSString*) sessionIdentifier {
size_t length = olm_session_id_length(_session);
NSMutableData *idData = [NSMutableData dataWithLength:length];
if (!idData) {
return nil;
}
size_t result = olm_session_id(_session, idData.mutableBytes, idData.length);
if (result == olm_error()) {
const char *error = olm_session_last_error(_session);
NSAssert(NO, @"olm_session_id error: %s", error);
return nil;
}
NSString *idString = [[NSString alloc] initWithData:idData encoding:NSUTF8StringEncoding];
return idString;
}
- (OLMMessage*) encryptMessage:(NSString*)message {
size_t messageType = olm_encrypt_message_type(_session);
size_t randomLength = olm_encrypt_random_length(_session);
NSMutableData *random = [OLMUtility randomBytesOfLength:randomLength];
NSData *plaintextData = [message dataUsingEncoding:NSUTF8StringEncoding];
size_t ciphertextLength = olm_encrypt_message_length(_session, plaintextData.length);
NSMutableData *ciphertext = [NSMutableData dataWithLength:ciphertextLength];
if (!ciphertext) {
return nil;
}
size_t result = olm_encrypt(_session, plaintextData.bytes, plaintextData.length, random.mutableBytes, random.length, ciphertext.mutableBytes, ciphertext.length);
if (result == olm_error()) {
const char *error = olm_session_last_error(_session);
NSAssert(NO, @"olm_encrypt error: %s", error);
return nil;
}
NSString *ciphertextString = [[NSString alloc] initWithData:ciphertext encoding:NSUTF8StringEncoding];
OLMMessage *encryptedMessage = [[OLMMessage alloc] initWithCiphertext:ciphertextString type:messageType];
return encryptedMessage;
}
- (NSString*) decryptMessage:(OLMMessage*)message {
NSParameterAssert(message != nil);
NSData *messageData = [message.ciphertext dataUsingEncoding:NSUTF8StringEncoding];
if (!messageData) {
return nil;
}
NSMutableData *mutMessage = messageData.mutableCopy;
size_t maxPlaintextLength = olm_decrypt_max_plaintext_length(_session, message.type, mutMessage.mutableBytes, mutMessage.length);
if (maxPlaintextLength == olm_error()) {
const char *error = olm_session_last_error(_session);
NSAssert(NO, @"olm_decrypt_max_plaintext_length error: %s", error);
return nil;
}
// message buffer is destroyed by olm_decrypt_max_plaintext_length
mutMessage = messageData.mutableCopy;
NSMutableData *plaintextData = [NSMutableData dataWithLength:maxPlaintextLength];
size_t plaintextLength = olm_decrypt(_session, message.type, mutMessage.mutableBytes, mutMessage.length, plaintextData.mutableBytes, plaintextData.length);
if (plaintextLength == olm_error()) {
const char *error = olm_session_last_error(_session);
NSAssert(NO, @"olm_decrypt error: %s", error);
return nil;
}
plaintextData.length = plaintextLength;
NSString *plaintext = [[NSString alloc] initWithData:plaintextData encoding:NSUTF8StringEncoding];
return plaintext;
}
#pragma mark OLMSerializable
/** Initializes from encrypted serialized data. Will throw error if invalid key or invalid base64. */
- (instancetype) initWithSerializedData:(NSString*)serializedData key:(NSData*)key error:(NSError**)error {
self = [self init];
if (!self) {
return nil;
}
NSParameterAssert(key.length > 0);
NSParameterAssert(serializedData.length > 0);
if (key.length == 0 || serializedData.length == 0) {
if (error) {
*error = [NSError errorWithDomain:@"org.matrix.olm" code:0 userInfo:@{NSLocalizedDescriptionKey: @"Bad length."}];
}
return nil;
}
NSMutableData *pickle = [serializedData dataUsingEncoding:NSUTF8StringEncoding].mutableCopy;
size_t result = olm_unpickle_session(_session, key.bytes, key.length, pickle.mutableBytes, pickle.length);
if (result == olm_error()) {
const char *olm_error = olm_session_last_error(_session);
NSString *errorString = [NSString stringWithUTF8String:olm_error];
if (error && errorString) {
*error = [NSError errorWithDomain:@"org.matrix.olm" code:0 userInfo:@{NSLocalizedDescriptionKey: errorString}];
}
return nil;
}
return self;
}
/** Serializes and encrypts object data, outputs base64 blob */
- (NSString*) serializeDataWithKey:(NSData*)key error:(NSError**)error {
NSParameterAssert(key.length > 0);
size_t length = olm_pickle_session_length(_session);
NSMutableData *pickled = [NSMutableData dataWithLength:length];
size_t result = olm_pickle_session(_session, key.bytes, key.length, pickled.mutableBytes, pickled.length);
if (result == olm_error()) {
const char *olm_error = olm_session_last_error(_session);
NSString *errorString = [NSString stringWithUTF8String:olm_error];
if (error && errorString) {
*error = [NSError errorWithDomain:@"org.matrix.olm" code:0 userInfo:@{NSLocalizedDescriptionKey: errorString}];
}
return nil;
}
NSString *pickleString = [[NSString alloc] initWithData:pickled encoding:NSUTF8StringEncoding];
return pickleString;
}
#pragma mark NSSecureCoding
+ (BOOL) supportsSecureCoding {
return YES;
}
#pragma mark NSCoding
- (id)initWithCoder:(NSCoder *)decoder {
NSString *version = [decoder decodeObjectOfClass:[NSString class] forKey:@"version"];
NSError *error = nil;
if ([version isEqualToString:@"1"]) {
NSString *pickle = [decoder decodeObjectOfClass:[NSString class] forKey:@"pickle"];
NSData *key = [decoder decodeObjectOfClass:[NSData class] forKey:@"key"];
self = [self initWithSerializedData:pickle key:key error:&error];
}
NSParameterAssert(error == nil);
NSParameterAssert(self != nil);
if (!self) {
return nil;
}
return self;
}
- (void)encodeWithCoder:(NSCoder *)encoder {
NSData *key = [OLMUtility randomBytesOfLength:32];
NSError *error = nil;
NSString *pickle = [self serializeDataWithKey:key error:&error];
NSParameterAssert(pickle.length > 0 && error == nil);
[encoder encodeObject:pickle forKey:@"pickle"];
[encoder encodeObject:key forKey:@"key"];
[encoder encodeObject:@"1" forKey:@"version"];
}
@end
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