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Diffstat (limited to 'xcode/OLMKit/OLMPkDecryption.m')
| -rw-r--r-- | xcode/OLMKit/OLMPkDecryption.m | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/xcode/OLMKit/OLMPkDecryption.m b/xcode/OLMKit/OLMPkDecryption.m new file mode 100644 index 0000000..75fe5f2 --- /dev/null +++ b/xcode/OLMKit/OLMPkDecryption.m @@ -0,0 +1,295 @@ +/* + Copyright 2018 New Vector Ltd + + Licensed under the Apache License, Version 2.0 (the "License"); + you may not use this file except in compliance with the License. + You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + + Unless required by applicable law or agreed to in writing, software + distributed under the License is distributed on an "AS IS" BASIS, + WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + See the License for the specific language governing permissions and + limitations under the License. + */ + +#import "OLMPkDecryption.h" + +#include "olm/olm.h" +#include "olm/pk.h" +#include "OLMUtility.h" + +@interface OLMPkDecryption () +{ + OlmPkDecryption *session; +} +@end + +@implementation OLMPkDecryption + +- (void)dealloc { + olm_clear_pk_decryption(session); + free(session); +} + +- (instancetype)init { + self = [super init]; + if (self) { + session = (OlmPkDecryption *)malloc(olm_pk_decryption_size()); + olm_pk_decryption(session); + } + return self; +} + +- (NSString *)setPrivateKey:(NSData *)privateKey error:(NSError *__autoreleasing _Nullable *)error { + size_t publicKeyLength = olm_pk_key_length(); + NSMutableData *publicKeyData = [NSMutableData dataWithLength:publicKeyLength]; + if (!publicKeyData) { + return nil; + } + + size_t result = olm_pk_key_from_private(session, + publicKeyData.mutableBytes, publicKeyLength, + (void*)privateKey.bytes, privateKey.length); + if (result == olm_error()) { + const char *olm_error = olm_pk_decryption_last_error(session); + NSLog(@"[OLMPkDecryption] setPrivateKey: olm_pk_key_from_private error: %s", olm_error); + + NSString *errorString = [NSString stringWithUTF8String:olm_error]; + if (error && olm_error && errorString) { + *error = [NSError errorWithDomain:OLMErrorDomain + code:0 + userInfo:@{ + NSLocalizedDescriptionKey: errorString, + NSLocalizedFailureReasonErrorKey: [NSString stringWithFormat:@"olm_pk_key_from_private error: %@", errorString] + }]; + } + return nil; + } + + NSString *publicKey = [[NSString alloc] initWithData:publicKeyData encoding:NSUTF8StringEncoding]; + return publicKey; +} + +- (NSString *)generateKey:(NSError *__autoreleasing _Nullable *)error { + size_t randomLength = olm_pk_private_key_length(); + NSMutableData *random = [OLMUtility randomBytesOfLength:randomLength]; + if (!random) { + return nil; + } + + size_t publicKeyLength = olm_pk_key_length(); + NSMutableData *publicKeyData = [NSMutableData dataWithLength:publicKeyLength]; + if (!publicKeyData) { + return nil; + } + + size_t result = olm_pk_key_from_private(session, + publicKeyData.mutableBytes, publicKeyData.length, + random.mutableBytes, randomLength); + [random resetBytesInRange:NSMakeRange(0, randomLength)]; + if (result == olm_error()) { + const char *olm_error = olm_pk_decryption_last_error(session); + NSLog(@"[OLMPkDecryption] generateKey: olm_pk_key_from_private error: %s", olm_error); + + NSString *errorString = [NSString stringWithUTF8String:olm_error]; + if (error && olm_error && errorString) { + *error = [NSError errorWithDomain:OLMErrorDomain + code:0 + userInfo:@{ + NSLocalizedDescriptionKey: errorString, + NSLocalizedFailureReasonErrorKey: [NSString stringWithFormat:@"olm_pk_key_from_private error: %@", errorString] + }]; + } + return nil; + } + + NSString *publicKey = [[NSString alloc] initWithData:publicKeyData encoding:NSUTF8StringEncoding]; + return publicKey; +} + +- (NSData *)privateKey { + size_t privateKeyLength = olm_pk_private_key_length(); + NSMutableData *privateKeyData = [NSMutableData dataWithLength:privateKeyLength]; + if (!privateKeyData) { + return nil; + } + + size_t result = olm_pk_get_private_key(session, + privateKeyData.mutableBytes, privateKeyLength); + if (result == olm_error()) { + const char *olm_error = olm_pk_decryption_last_error(session); + NSLog(@"[OLMPkDecryption] privateKey: olm_pk_get_private_key error: %s", olm_error); + return nil; + } + + NSData *privateKey = [privateKeyData copy]; + [privateKeyData resetBytesInRange:NSMakeRange(0, privateKeyData.length)]; + + return privateKey; +} + +-(NSString *)decryptMessage:(OLMPkMessage *)message error:(NSError *__autoreleasing _Nullable *)error { + NSData *messageData = [message.ciphertext dataUsingEncoding:NSUTF8StringEncoding]; + NSData *macData = [message.mac dataUsingEncoding:NSUTF8StringEncoding]; + NSData *ephemeralKeyData = [message.ephemeralKey dataUsingEncoding:NSUTF8StringEncoding]; + if (!messageData || !macData || !ephemeralKeyData) { + return nil; + } + + NSMutableData *mutMessage = messageData.mutableCopy; + size_t maxPlaintextLength = olm_pk_max_plaintext_length(session, mutMessage.length); + if (maxPlaintextLength == olm_error()) { + const char *olm_error = olm_pk_decryption_last_error(session); + + NSString *errorString = [NSString stringWithUTF8String:olm_error]; + NSLog(@"[OLMPkDecryption] decryptMessage: olm_pk_max_plaintext_length error: %@", errorString); + + if (error && olm_error && errorString) { + *error = [NSError errorWithDomain:OLMErrorDomain + code:0 + userInfo:@{ + NSLocalizedDescriptionKey: errorString, + NSLocalizedFailureReasonErrorKey: [NSString stringWithFormat:@"olm_pk_max_plaintext_length error: %@", errorString] + }]; + } + + return nil; + } + + mutMessage = messageData.mutableCopy; + NSMutableData *plaintextData = [NSMutableData dataWithLength:maxPlaintextLength]; + size_t plaintextLength = olm_pk_decrypt(session, + ephemeralKeyData.bytes, ephemeralKeyData.length, + macData.bytes, macData.length, + mutMessage.mutableBytes, mutMessage.length, + plaintextData.mutableBytes, plaintextData.length); + if (plaintextLength == olm_error()) { + const char *olm_error = olm_pk_decryption_last_error(session); + + NSString *errorString = [NSString stringWithUTF8String:olm_error]; + NSLog(@"[OLMPkDecryption] decryptMessage: olm_pk_decrypt error: %@", errorString); + + if (error && olm_error && errorString) { + *error = [NSError errorWithDomain:OLMErrorDomain + code:0 + userInfo:@{ + NSLocalizedDescriptionKey: errorString, + NSLocalizedFailureReasonErrorKey: [NSString stringWithFormat:@"olm_decrypt error: %@", errorString] + }]; + } + + return nil; + } + + plaintextData.length = plaintextLength; + NSString *plaintext = [[NSString alloc] initWithData:plaintextData encoding:NSUTF8StringEncoding]; + [plaintextData resetBytesInRange:NSMakeRange(0, plaintextData.length)]; + 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 *__autoreleasing *)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:OLMErrorDomain code:0 userInfo:@{NSLocalizedDescriptionKey: @"Bad length."}]; + } + return nil; + } + + size_t ephemeralLength = olm_pk_key_length(); + NSMutableData *ephemeralBuffer = [NSMutableData dataWithLength:ephemeralLength]; + + NSMutableData *pickle = [serializedData dataUsingEncoding:NSUTF8StringEncoding].mutableCopy; + size_t result = olm_unpickle_pk_decryption(session, + key.bytes, key.length, + pickle.mutableBytes, pickle.length, + ephemeralBuffer.mutableBytes, ephemeralLength); + [pickle resetBytesInRange:NSMakeRange(0, pickle.length)]; + if (result == olm_error()) { + const char *olm_error = olm_pk_decryption_last_error(session); + NSString *errorString = [NSString stringWithUTF8String:olm_error]; + if (error && errorString) { + *error = [NSError errorWithDomain:OLMErrorDomain 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_pk_decryption_length(session); + NSMutableData *pickled = [NSMutableData dataWithLength:length]; + + size_t result = olm_pickle_pk_decryption(session, + key.bytes, key.length, + pickled.mutableBytes, pickled.length); + if (result == olm_error()) { + const char *olm_error = olm_pk_decryption_last_error(session); + NSString *errorString = [NSString stringWithUTF8String:olm_error]; + if (error && errorString) { + *error = [NSError errorWithDomain:OLMErrorDomain code:0 userInfo:@{NSLocalizedDescriptionKey: errorString}]; + } + return nil; + } + + NSString *pickleString = [[NSString alloc] initWithData:pickled encoding:NSUTF8StringEncoding]; + [pickled resetBytesInRange:NSMakeRange(0, pickled.length)]; + + 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 |