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/*
* 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 "error/s2n_errno.h"
#include "tls/s2n_crypto.h"
#include "utils/s2n_blob.h"
#define SEQUENCE_NUMBER_POWER 8
int s2n_increment_sequence_number(struct s2n_blob *sequence_number)
{
for (uint32_t j = sequence_number->size; j > 0; j--) {
uint32_t i = j - 1;
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)
{
POSIX_ENSURE_REF(sequence_number);
uint8_t shift = 0;
*output = 0;
for (uint32_t i = sequence_number->size; i > 0; i--) {
*output += ((uint64_t) sequence_number->data[i - 1]) << shift;
shift += SEQUENCE_NUMBER_POWER;
}
return S2N_SUCCESS;
}
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