79 lines
2.1 KiB
C
79 lines
2.1 KiB
C
/*
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* Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved.
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*
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* Licensed under the OpenSSL license (the "License"). You may not use
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* this file except in compliance with the License. You can obtain a copy
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* in the file LICENSE in the source distribution or at
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* https://www.openssl.org/source/license.html
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*/
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#include "../ssl_local.h"
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#include "record_local.h"
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/* mod 128 saturating subtract of two 64-bit values in big-endian order */
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static int satsub64be(const unsigned char *v1, const unsigned char *v2)
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{
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int64_t ret;
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uint64_t l1, l2;
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n2l8(v1, l1);
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n2l8(v2, l2);
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ret = l1 - l2;
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/* We do not permit wrap-around */
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if (l1 > l2 && ret < 0)
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return 128;
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else if (l2 > l1 && ret > 0)
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return -128;
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if (ret > 128)
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return 128;
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else if (ret < -128)
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return -128;
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else
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return (int)ret;
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}
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int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap)
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{
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int cmp;
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unsigned int shift;
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const unsigned char *seq = s->rlayer.read_sequence;
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cmp = satsub64be(seq, bitmap->max_seq_num);
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if (cmp > 0) {
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SSL3_RECORD_set_seq_num(RECORD_LAYER_get_rrec(&s->rlayer), seq);
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return 1; /* this record in new */
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}
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shift = -cmp;
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if (shift >= sizeof(bitmap->map) * 8)
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return 0; /* stale, outside the window */
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else if (bitmap->map & (1UL << shift))
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return 0; /* record previously received */
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SSL3_RECORD_set_seq_num(RECORD_LAYER_get_rrec(&s->rlayer), seq);
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return 1;
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}
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void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap)
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{
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int cmp;
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unsigned int shift;
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const unsigned char *seq = RECORD_LAYER_get_read_sequence(&s->rlayer);
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cmp = satsub64be(seq, bitmap->max_seq_num);
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if (cmp > 0) {
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shift = cmp;
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if (shift < sizeof(bitmap->map) * 8)
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bitmap->map <<= shift, bitmap->map |= 1UL;
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else
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bitmap->map = 1UL;
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memcpy(bitmap->max_seq_num, seq, SEQ_NUM_SIZE);
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} else {
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shift = -cmp;
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if (shift < sizeof(bitmap->map) * 8)
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bitmap->map |= 1UL << shift;
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}
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}
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