Merge pull request #88 from matrix-org/manuroe/sas_pksigning

OLMKit: add Short Authentication String verification

1 files changed, 174 insertions, 0 deletions

diff --git a/xcode/OLMKit/OLMSAS.m b/xcode/OLMKit/OLMSAS.m
new file mode 100644
index 0000000..fed370b
--- /dev/null
+++ b/xcode/OLMKit/OLMSAS.m
@@ -0,0 +1,174 @@
+/*
+ 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 "OLMSAS.h"
+
+#include "olm/olm.h"
+#include "olm/sas.h"
+#include "OLMUtility.h"
+
+@interface OLMSAS () {
+    void *olmSASbuffer;
+    OlmSAS *olmSAS;
+}
+@end
+
+@implementation OLMSAS
+
+- (void)dealloc {
+    olm_clear_sas(olmSAS);
+    free(olmSASbuffer);
+}
+
+- (instancetype)init {
+    self = [super init];
+    if (self) {
+        olmSASbuffer = malloc(olm_sas_size());
+        olmSAS = olm_sas(olmSASbuffer);
+
+        size_t randomLength = olm_create_sas_random_length(olmSAS);
+        NSMutableData *random = [OLMUtility randomBytesOfLength:randomLength];
+        if (!random) {
+            return nil;
+        }
+
+        olm_create_sas(olmSAS, random.mutableBytes, randomLength);
+
+        [random resetBytesInRange:NSMakeRange(0, randomLength)];
+    }
+    return self;
+}
+
+- (NSString * _Nullable)publicKey {
+    size_t publicKeyLength = olm_sas_pubkey_length(olmSAS);
+    NSMutableData *publicKeyData = [NSMutableData dataWithLength:publicKeyLength];
+    if (!publicKeyData) {
+        return nil;
+    }
+
+    size_t result = olm_sas_get_pubkey(olmSAS, publicKeyData.mutableBytes, publicKeyLength);
+    if (result == olm_error()) {
+        const char *olm_error = olm_sas_last_error(olmSAS);
+        NSLog(@"[OLMSAS] publicKey: olm_sas_get_pubkey error: %s", olm_error);
+        return nil;
+    }
+
+    NSString *publicKey = [[NSString alloc] initWithData:publicKeyData encoding:NSUTF8StringEncoding];
+    return publicKey;
+}
+
+- (NSError * _Nullable)setTheirPublicKey:(NSString*)theirPublicKey {
+    NSMutableData *theirPublicKeyData = [theirPublicKey dataUsingEncoding:NSUTF8StringEncoding].mutableCopy;
+
+    size_t result = olm_sas_set_their_key(olmSAS, theirPublicKeyData.mutableBytes, theirPublicKeyData.length);
+    if (result == olm_error()) {
+        const char *olm_error = olm_sas_last_error(olmSAS);
+        NSLog(@"[OLMSAS] setTheirPublicKey: olm_sas_set_their_key error: %s", olm_error);
+
+        NSString *errorString = [NSString stringWithUTF8String:olm_error];
+        if (olm_error && errorString) {
+            return [NSError errorWithDomain:OLMErrorDomain
+                                       code:0
+                                   userInfo:@{
+                                              NSLocalizedDescriptionKey: errorString,
+                                              NSLocalizedFailureReasonErrorKey: [NSString stringWithFormat:@"olm_sas_set_their_key error: %@", errorString]
+                                              }];
+        }
+    }
+
+    return nil;
+}
+
+- (NSData *)generateBytes:(NSString *)info length:(NSUInteger)length {
+    NSData *infoData = [info dataUsingEncoding:NSUTF8StringEncoding];
+
+    NSMutableData *bytes = [NSMutableData dataWithLength:length];
+    if (!bytes) {
+        return nil;
+    }
+
+    olm_sas_generate_bytes(olmSAS, infoData.bytes, infoData.length, bytes.mutableBytes, length);
+    return bytes;
+}
+
+- (NSString *)calculateMac:(NSString *)input info:(NSString *)info error:(NSError *__autoreleasing  _Nullable *)error {
+    NSMutableData *inputData = [input dataUsingEncoding:NSUTF8StringEncoding].mutableCopy;
+    NSData *infoData = [info dataUsingEncoding:NSUTF8StringEncoding];
+
+    size_t macLength = olm_sas_mac_length(olmSAS);
+    NSMutableData *macData = [NSMutableData dataWithLength:macLength];
+    if (!macData) {
+        return nil;
+    }
+
+    size_t result = olm_sas_calculate_mac(olmSAS,
+                                          inputData.mutableBytes, inputData.length,
+                                          infoData.bytes, infoData.length,
+                                          macData.mutableBytes, macLength);
+    if (result == olm_error()) {
+        const char *olm_error = olm_sas_last_error(olmSAS);
+        NSLog(@"[OLMSAS] calculateMac: olm_sas_calculate_mac 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_sas_calculate_mac error: %@", errorString]
+                                                }];
+        }
+        return nil;
+    }
+
+    NSString *mac = [[NSString alloc] initWithData:macData encoding:NSUTF8StringEncoding];
+    return mac;
+}
+
+- (NSString *)calculateMacLongKdf:(NSString *)input info:(NSString *)info error:(NSError *__autoreleasing  _Nullable *)error {
+    NSMutableData *inputData = [input dataUsingEncoding:NSUTF8StringEncoding].mutableCopy;
+    NSData *infoData = [info dataUsingEncoding:NSUTF8StringEncoding];
+
+    size_t macLength = olm_sas_mac_length(olmSAS);
+    NSMutableData *macData = [NSMutableData dataWithLength:macLength];
+    if (!macData) {
+        return nil;
+    }
+
+    size_t result = olm_sas_calculate_mac_long_kdf(olmSAS,
+                                                   inputData.mutableBytes, inputData.length,
+                                                   infoData.bytes, infoData.length,
+                                                   macData.mutableBytes, macLength);
+    if (result == olm_error()) {
+        const char *olm_error = olm_sas_last_error(olmSAS);
+        NSLog(@"[OLMSAS] calculateMacLongKdf: olm_sas_calculate_mac 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_sas_calculate_mac_long_kdf error: %@", errorString]
+                                                }];
+        }
+        return nil;
+    }
+
+    NSString *mac = [[NSString alloc] initWithData:macData encoding:NSUTF8StringEncoding];
+    return mac;
+}
+
+@end