aboutsummaryrefslogtreecommitdiff
path: root/xcode/OLMKit/OLMInboundGroupSession.m
blob: 6ef51c3ed4d5a685979111c522170bc2178dba02 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
/*
 Copyright 2016 OpenMarket Ltd
 Copyright 2016 Vector Creations 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 "OLMInboundGroupSession.h"

#import "OLMUtility.h"
#include "olm/olm.h"

@interface OLMInboundGroupSession ()
{
    OlmInboundGroupSession *session;
}
@end


@implementation OLMInboundGroupSession

- (void)dealloc {
    olm_clear_inbound_group_session(session);
    free(session);
}

- (instancetype)init {
    self = [super init];
    if (self)
    {
        session = malloc(olm_inbound_group_session_size());
        if (session) {
            session = olm_inbound_group_session(session);
        }

        if (!session) {
            return nil;
        }
    }
    return self;
}

- (instancetype)initInboundGroupSessionWithSessionKey:(NSString *)sessionKey error:(NSError**)error {
    self = [self init];
    if (self) {
        NSData *sessionKeyData = [sessionKey dataUsingEncoding:NSUTF8StringEncoding];
        size_t result = olm_init_inbound_group_session(session, sessionKeyData.bytes, sessionKeyData.length);
        if (result == olm_error())   {
            const char *olm_error = olm_inbound_group_session_last_error(session);

            NSString *errorString = [NSString stringWithUTF8String:olm_error];
            NSLog(@"olm_init_inbound_group_session error: %@", errorString);

            if (error && olm_error && errorString) {
                *error = [NSError errorWithDomain:OLMErrorDomain
                                             code:0
                                         userInfo:@{
                                                    NSLocalizedDescriptionKey: errorString,
                                                    NSLocalizedFailureReasonErrorKey: [NSString stringWithFormat:@"olm_init_inbound_group_session error: %@", errorString]
                                                    }];
            }

            return nil;
        }
    }
    return self;
}

- (NSString *)sessionIdentifier {
    size_t length = olm_inbound_group_session_id_length(session);
    NSMutableData *idData = [NSMutableData dataWithLength:length];
    if (!idData) {
        return nil;
    }
    size_t result = olm_inbound_group_session_id(session, idData.mutableBytes, idData.length);
    if (result == olm_error()) {
        const char *error = olm_inbound_group_session_last_error(session);
        NSLog(@"olm_inbound_group_session_id error: %s", error);
        return nil;
    }
    NSString *idString = [[NSString alloc] initWithData:idData encoding:NSUTF8StringEncoding];
    return idString;
}

- (NSString *)decryptMessage:(NSString *)message messageIndex:(NSUInteger*)messageIndex error:(NSError**)error
{
    NSParameterAssert(message != nil);
    NSData *messageData = [message dataUsingEncoding:NSUTF8StringEncoding];
    if (!messageData) {
        return nil;
    }
    NSMutableData *mutMessage = messageData.mutableCopy;
    size_t maxPlaintextLength = olm_group_decrypt_max_plaintext_length(session, mutMessage.mutableBytes, mutMessage.length);
    if (maxPlaintextLength == olm_error()) {
        const char *olm_error = olm_inbound_group_session_last_error(session);

        NSString *errorString = [NSString stringWithUTF8String:olm_error];
        NSLog(@"olm_group_decrypt_max_plaintext_length error: %@", errorString);

        if (error && olm_error && errorString) {
            *error = [NSError errorWithDomain:OLMErrorDomain
                                         code:0
                                     userInfo:@{
                                                NSLocalizedDescriptionKey: errorString,
                                                NSLocalizedFailureReasonErrorKey: [NSString stringWithFormat:@"olm_group_decrypt_max_plaintext_length error: %@", errorString]
                                                }];
        }
        
        return nil;
    }
    // message buffer is destroyed by olm_group_decrypt_max_plaintext_length
    mutMessage = messageData.mutableCopy;
    NSMutableData *plaintextData = [NSMutableData dataWithLength:maxPlaintextLength];

    uint32_t message_index;
    size_t plaintextLength = olm_group_decrypt(session, mutMessage.mutableBytes, mutMessage.length, plaintextData.mutableBytes, plaintextData.length, &message_index);
    if (plaintextLength == olm_error()) {
        const char *olm_error = olm_inbound_group_session_last_error(session);

        NSString *errorString = [NSString stringWithUTF8String:olm_error];
        NSLog(@"olm_group_decrypt error: %@", errorString);

        if (error && olm_error && errorString) {
            *error = [NSError errorWithDomain:OLMErrorDomain
                                         code:0
                                     userInfo:@{
                                                NSLocalizedDescriptionKey: errorString,
                                                NSLocalizedFailureReasonErrorKey: [NSString stringWithFormat:@"olm_group_decrypt error: %@", errorString]
                                                }];
        }

        return nil;
    }
    plaintextData.length = plaintextLength;
    NSString *plaintext = [[NSString alloc] initWithData:plaintextData encoding:NSUTF8StringEncoding];
    [plaintextData resetBytesInRange:NSMakeRange(0, plaintextData.length)];

    if (messageIndex)
    {
        *messageIndex = message_index;
    }

    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;
    }
    NSMutableData *pickle = [serializedData dataUsingEncoding:NSUTF8StringEncoding].mutableCopy;
    size_t result = olm_unpickle_inbound_group_session(session, key.bytes, key.length, pickle.mutableBytes, pickle.length);
    if (result == olm_error()) {
        const char *olm_error = olm_inbound_group_session_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_inbound_group_session_length(session);
    NSMutableData *pickled = [NSMutableData dataWithLength:length];
    size_t result = olm_pickle_inbound_group_session(session, key.bytes, key.length, pickled.mutableBytes, pickled.length);
    if (result == olm_error()) {
        const char *olm_error = olm_inbound_group_session_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];
    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