[331] | 1 | /*
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| 2 | * Copyright 2005-2016 The OpenSSL Project Authors. All Rights Reserved.
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| 3 | *
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| 4 | * Licensed under the OpenSSL license (the "License"). You may not use
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| 5 | * this file except in compliance with the License. You can obtain a copy
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| 6 | * in the file LICENSE in the source distribution or at
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| 7 | * https://www.openssl.org/source/license.html
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| 8 | */
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| 9 |
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| 10 | #include "../ssl_locl.h"
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| 11 | #include "record_locl.h"
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| 12 |
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| 13 | /* mod 128 saturating subtract of two 64-bit values in big-endian order */
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| 14 | static int satsub64be(const unsigned char *v1, const unsigned char *v2)
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| 15 | {
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| 16 | int64_t ret;
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| 17 | uint64_t l1, l2;
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| 18 |
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| 19 | n2l8(v1, l1);
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| 20 | n2l8(v2, l2);
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| 21 |
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| 22 | ret = l1 - l2;
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| 23 |
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| 24 | /* We do not permit wrap-around */
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| 25 | if (l1 > l2 && ret < 0)
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| 26 | return 128;
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| 27 | else if (l2 > l1 && ret > 0)
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| 28 | return -128;
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| 29 |
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| 30 | if (ret > 128)
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| 31 | return 128;
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| 32 | else if (ret < -128)
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| 33 | return -128;
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| 34 | else
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| 35 | return (int)ret;
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| 36 | }
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| 37 |
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| 38 | int dtls1_record_replay_check(SSL *s, DTLS1_BITMAP *bitmap)
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| 39 | {
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| 40 | int cmp;
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| 41 | unsigned int shift;
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| 42 | const unsigned char *seq = s->rlayer.read_sequence;
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| 43 |
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| 44 | cmp = satsub64be(seq, bitmap->max_seq_num);
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| 45 | if (cmp > 0) {
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| 46 | SSL3_RECORD_set_seq_num(RECORD_LAYER_get_rrec(&s->rlayer), seq);
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| 47 | return 1; /* this record in new */
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| 48 | }
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| 49 | shift = -cmp;
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| 50 | if (shift >= sizeof(bitmap->map) * 8)
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| 51 | return 0; /* stale, outside the window */
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| 52 | else if (bitmap->map & (1UL << shift))
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| 53 | return 0; /* record previously received */
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| 54 |
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| 55 | SSL3_RECORD_set_seq_num(RECORD_LAYER_get_rrec(&s->rlayer), seq);
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| 56 | return 1;
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| 57 | }
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| 58 |
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| 59 | void dtls1_record_bitmap_update(SSL *s, DTLS1_BITMAP *bitmap)
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| 60 | {
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| 61 | int cmp;
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| 62 | unsigned int shift;
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| 63 | const unsigned char *seq = RECORD_LAYER_get_read_sequence(&s->rlayer);
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| 64 |
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| 65 | cmp = satsub64be(seq, bitmap->max_seq_num);
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| 66 | if (cmp > 0) {
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| 67 | shift = cmp;
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| 68 | if (shift < sizeof(bitmap->map) * 8)
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| 69 | bitmap->map <<= shift, bitmap->map |= 1UL;
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| 70 | else
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| 71 | bitmap->map = 1UL;
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| 72 | memcpy(bitmap->max_seq_num, seq, SEQ_NUM_SIZE);
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| 73 | } else {
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| 74 | shift = -cmp;
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| 75 | if (shift < sizeof(bitmap->map) * 8)
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| 76 | bitmap->map |= 1UL << shift;
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| 77 | }
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| 78 | }
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