121 lines
3.7 KiB
C
121 lines
3.7 KiB
C
/*
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* key.c
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*
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* key usage limits enforcement
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*
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* David A. Mcgrew
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* Cisco Systems, Inc.
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*/
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/*
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*
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* Copyright (c) 2001-2017 Cisco Systems, Inc.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above
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* copyright notice, this list of conditions and the following
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* disclaimer in the documentation and/or other materials provided
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* with the distribution.
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*
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* Neither the name of the Cisco Systems, Inc. nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
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* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
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* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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* SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
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* OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include "key.h"
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#define soft_limit 0x10000
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srtp_err_status_t srtp_key_limit_set (srtp_key_limit_t key, const srtp_xtd_seq_num_t s)
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{
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#ifdef NO_64BIT_MATH
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if (high32(s) == 0 && low32(s) < soft_limit) {
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return srtp_err_status_bad_param;
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}
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#else
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if (s < soft_limit) {
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return srtp_err_status_bad_param;
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}
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#endif
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key->num_left = s;
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key->state = srtp_key_state_normal;
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return srtp_err_status_ok;
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}
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srtp_err_status_t srtp_key_limit_clone (srtp_key_limit_t original, srtp_key_limit_t *new_key)
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{
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if (original == NULL) {
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return srtp_err_status_bad_param;
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}
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*new_key = original;
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return srtp_err_status_ok;
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}
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srtp_err_status_t srtp_key_limit_check (const srtp_key_limit_t key)
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{
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if (key->state == srtp_key_state_expired) {
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return srtp_err_status_key_expired;
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}
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return srtp_err_status_ok;
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}
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srtp_key_event_t srtp_key_limit_update (srtp_key_limit_t key)
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{
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#ifdef NO_64BIT_MATH
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if (low32(key->num_left) == 0) {
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// carry
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key->num_left = make64(high32(key->num_left) - 1, low32(key->num_left) - 1);
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}else {
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// no carry
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key->num_left = make64(high32(key->num_left), low32(key->num_left) - 1);
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}
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if (high32(key->num_left) != 0 || low32(key->num_left) >= soft_limit) {
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return srtp_key_event_normal; /* we're above the soft limit */
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}
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#else
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key->num_left--;
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if (key->num_left >= soft_limit) {
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return srtp_key_event_normal; /* we're above the soft limit */
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}
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#endif
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if (key->state == srtp_key_state_normal) {
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/* we just passed the soft limit, so change the state */
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key->state = srtp_key_state_past_soft_limit;
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}
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#ifdef NO_64BIT_MATH
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if (low32(key->num_left) == 0 && high32(key->num_left == 0))
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#else
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if (key->num_left < 1)
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#endif
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{ /* we just hit the hard limit */
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key->state = srtp_key_state_expired;
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return srtp_key_event_hard_limit;
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}
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return srtp_key_event_soft_limit;
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}
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