1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/netwerk/srtp/src/crypto/kernel/key.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,115 @@
1.4 +/*
1.5 + * key.c
1.6 + *
1.7 + * key usage limits enforcement
1.8 + *
1.9 + * David A. Mcgrew
1.10 + * Cisco Systems, Inc.
1.11 + */
1.12 +/*
1.13 + *
1.14 + * Copyright (c) 2001-2006 Cisco Systems, Inc.
1.15 + * All rights reserved.
1.16 + *
1.17 + * Redistribution and use in source and binary forms, with or without
1.18 + * modification, are permitted provided that the following conditions
1.19 + * are met:
1.20 + *
1.21 + * Redistributions of source code must retain the above copyright
1.22 + * notice, this list of conditions and the following disclaimer.
1.23 + *
1.24 + * Redistributions in binary form must reproduce the above
1.25 + * copyright notice, this list of conditions and the following
1.26 + * disclaimer in the documentation and/or other materials provided
1.27 + * with the distribution.
1.28 + *
1.29 + * Neither the name of the Cisco Systems, Inc. nor the names of its
1.30 + * contributors may be used to endorse or promote products derived
1.31 + * from this software without specific prior written permission.
1.32 + *
1.33 + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
1.34 + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
1.35 + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
1.36 + * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
1.37 + * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
1.38 + * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
1.39 + * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
1.40 + * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
1.41 + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
1.42 + * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
1.43 + * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
1.44 + * OF THE POSSIBILITY OF SUCH DAMAGE.
1.45 + *
1.46 + */
1.47 +
1.48 +#include "key.h"
1.49 +
1.50 +#define soft_limit 0x10000
1.51 +
1.52 +err_status_t
1.53 +key_limit_set(key_limit_t key, const xtd_seq_num_t s) {
1.54 +#ifdef NO_64BIT_MATH
1.55 + if (high32(s) == 0 && low32(s) < soft_limit)
1.56 + return err_status_bad_param;
1.57 +#else
1.58 + if (s < soft_limit)
1.59 + return err_status_bad_param;
1.60 +#endif
1.61 + key->num_left = s;
1.62 + key->state = key_state_normal;
1.63 + return err_status_ok;
1.64 +}
1.65 +
1.66 +err_status_t
1.67 +key_limit_clone(key_limit_t original, key_limit_t *new_key) {
1.68 + if (original == NULL)
1.69 + return err_status_bad_param;
1.70 + *new_key = original;
1.71 + return err_status_ok;
1.72 +}
1.73 +
1.74 +err_status_t
1.75 +key_limit_check(const key_limit_t key) {
1.76 + if (key->state == key_state_expired)
1.77 + return err_status_key_expired;
1.78 + return err_status_ok;
1.79 +}
1.80 +
1.81 +key_event_t
1.82 +key_limit_update(key_limit_t key) {
1.83 +#ifdef NO_64BIT_MATH
1.84 + if (low32(key->num_left) == 0)
1.85 + {
1.86 + // carry
1.87 + key->num_left = make64(high32(key->num_left)-1,low32(key->num_left) - 1);
1.88 + }
1.89 + else
1.90 + {
1.91 + // no carry
1.92 + key->num_left = make64(high32(key->num_left),low32(key->num_left) - 1);
1.93 + }
1.94 + if (high32(key->num_left) != 0 || low32(key->num_left) >= soft_limit) {
1.95 + return key_event_normal; /* we're above the soft limit */
1.96 + }
1.97 +#else
1.98 + key->num_left--;
1.99 + if (key->num_left >= soft_limit) {
1.100 + return key_event_normal; /* we're above the soft limit */
1.101 + }
1.102 +#endif
1.103 + if (key->state == key_state_normal) {
1.104 + /* we just passed the soft limit, so change the state */
1.105 + key->state = key_state_past_soft_limit;
1.106 + }
1.107 +#ifdef NO_64BIT_MATH
1.108 + if (low32(key->num_left) == 0 && high32(key->num_left == 0))
1.109 +#else
1.110 + if (key->num_left < 1)
1.111 +#endif
1.112 + { /* we just hit the hard limit */
1.113 + key->state = key_state_expired;
1.114 + return key_event_hard_limit;
1.115 + }
1.116 + return key_event_soft_limit;
1.117 +}
1.118 +
