aboutsummaryrefslogtreecommitdiffstats
path: root/contrib/restricted/aws/s2n/crypto/s2n_sequence.c
blob: 1deac1b522cbdac7af2782c96cd4894f1fa8db93 (plain) (blame)
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
/* 
 * Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved. 
 * 
 * Licensed under the Apache License, Version 2.0 (the "License"). 
 * You may not use this file except in compliance with the License. 
 * A copy of the License is located at 
 * 
 *  http://aws.amazon.com/apache2.0 
 * 
 * or in the "license" file accompanying this file. This file 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. 
 */ 
 
#include "crypto/s2n_sequence.h" 
 
#include "tls/s2n_crypto.h" 
 
#include "error/s2n_errno.h" 
 
#include "utils/s2n_blob.h" 
 
#define SEQUENCE_NUMBER_POWER 8 
 
int s2n_increment_sequence_number(struct s2n_blob *sequence_number) 
{ 
    for (int i = sequence_number->size - 1; i >= 0; i--) { 
        sequence_number->data[i] += 1; 
        if (sequence_number->data[i]) { 
            break; 
        } 
 
        /* RFC 5246 6.1: If a TLS implementation would need to wrap a sequence number, it must 
         * renegotiate instead. We don't support renegotiation. Caller needs to create a new session. 
         * This condition is very unlikely. It requires 2^64 - 1 records to be sent. 
         */ 
        S2N_ERROR_IF(i == 0, S2N_ERR_RECORD_LIMIT); 
 
        /* seq[i] wrapped, so let it carry */ 
    } 
 
    return 0; 
} 
 
int s2n_sequence_number_to_uint64(struct s2n_blob *sequence_number, uint64_t *output) 
{ 
    notnull_check(sequence_number); 
 
    uint8_t shift = 0; 
    *output = 0; 
 
    for (int i = sequence_number->size - 1; i >= 0; i--) { 
        *output += ((uint64_t) sequence_number->data[i]) << shift; 
        shift += SEQUENCE_NUMBER_POWER; 
    } 
    return S2N_SUCCESS; 
}