mirror of
https://github.com/cryb-to/cryb-otp.git
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75 lines
2.5 KiB
C
75 lines
2.5 KiB
C
/*-
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* Copyright (c) 2013-2018 The University of Oslo
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* Copyright (c) 2016-2018 Dag-Erling Smørgrav
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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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* 1. 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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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. The name of the author may not be used to endorse or promote
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* products derived from this software without specific prior written
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* permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR 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, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "cryb/impl.h"
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#include <stddef.h>
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#include <stdint.h>
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#include <cryb/assert.h>
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#include <cryb/oath.h>
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#include <cryb/otp.h>
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#include "cryb_otp_impl.h"
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/*
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* Check whether a given response is correct for the given keyfile.
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*/
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int
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otp_verify(oath_key *key, unsigned long response)
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{
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uint64_t prev;
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int ret;
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switch (key->mode) {
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case om_hotp:
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prev = key->counter;
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ret = oath_hotp_match(key, response, HOTP_WINDOW);
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assertf(key->counter >= prev, "counter went backwads");
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if (ret > 0) {
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assertf(key->counter > prev, "counter did not advance");
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ret = key->counter - prev - 1;
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}
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break;
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case om_totp:
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prev = key->lastused;
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ret = oath_totp_match(key, response, TOTP_WINDOW);
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assertf(key->lastused >= prev, "lastused went backwards");
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if (ret > 0) {
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assertf(key->lastused > prev, "lastused did not advance");
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ret = key->lastused - prev / key->timestep;
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}
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break;
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default:
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ret = -1;
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}
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/* oath_*_ret() return -1 on error, 0 on failure, 1 on success */
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return (ret);
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}
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