150 lines
4.4 KiB
C
150 lines
4.4 KiB
C
/* $OpenBSD: rsa.c,v 1.28 2006/08/03 03:34:42 deraadt Exp $ */
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/*
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* Author: Tatu Ylonen <ylo@cs.hut.fi>
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* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
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* All rights reserved
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*
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* As far as I am concerned, the code I have written for this software
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* can be used freely for any purpose. Any derived versions of this
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* software must be clearly marked as such, and if the derived work is
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* incompatible with the protocol description in the RFC file, it must be
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* called by a name other than "ssh" or "Secure Shell".
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*
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*
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* Copyright (c) 1999 Niels Provos. 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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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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*
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* Description of the RSA algorithm can be found e.g. from the following
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* sources:
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*
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* Bruce Schneier: Applied Cryptography. John Wiley & Sons, 1994.
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*
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* Jennifer Seberry and Josed Pieprzyk: Cryptography: An Introduction to
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* Computer Security. Prentice-Hall, 1989.
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*
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* Man Young Rhee: Cryptography and Secure Data Communications. McGraw-Hill,
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* 1994.
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*
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* R. Rivest, A. Shamir, and L. M. Adleman: Cryptographic Communications
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* System and Method. US Patent 4,405,829, 1983.
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*
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* Hans Riesel: Prime Numbers and Computer Methods for Factorization.
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* Birkhauser, 1994.
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*
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* The RSA Frequently Asked Questions document by RSA Data Security,
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* Inc., 1995.
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*
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* RSA in 3 lines of perl by Adam Back <aba@atlax.ex.ac.uk>, 1995, as
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* included below:
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*
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* [gone - had to be deleted - what a pity]
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*/
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#include "includes.h"
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#include <sys/types.h>
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#include <stdarg.h>
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#include <string.h>
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#include "xmalloc.h"
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#include "rsa.h"
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#include "log.h"
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void
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rsa_public_encrypt(BIGNUM *out, BIGNUM *in, RSA *key)
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{
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u_char *inbuf, *outbuf;
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int len, ilen, olen;
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if (BN_num_bits(key->e) < 2 || !BN_is_odd(key->e))
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fatal("rsa_public_encrypt() exponent too small or not odd");
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olen = BN_num_bytes(key->n);
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outbuf = xmalloc(olen);
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ilen = BN_num_bytes(in);
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inbuf = xmalloc(ilen);
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BN_bn2bin(in, inbuf);
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if ((len = RSA_public_encrypt(ilen, inbuf, outbuf, key,
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RSA_PKCS1_PADDING)) <= 0)
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fatal("rsa_public_encrypt() failed");
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BN_bin2bn(outbuf, len, out);
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memset(outbuf, 0, olen);
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memset(inbuf, 0, ilen);
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xfree(outbuf);
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xfree(inbuf);
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}
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int
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rsa_private_decrypt(BIGNUM *out, BIGNUM *in, RSA *key)
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{
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u_char *inbuf, *outbuf;
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int len, ilen, olen;
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olen = BN_num_bytes(key->n);
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outbuf = xmalloc(olen);
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ilen = BN_num_bytes(in);
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inbuf = xmalloc(ilen);
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BN_bn2bin(in, inbuf);
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if ((len = RSA_private_decrypt(ilen, inbuf, outbuf, key,
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RSA_PKCS1_PADDING)) <= 0) {
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error("rsa_private_decrypt() failed");
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} else {
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BN_bin2bn(outbuf, len, out);
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}
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memset(outbuf, 0, olen);
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memset(inbuf, 0, ilen);
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xfree(outbuf);
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xfree(inbuf);
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return len;
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}
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/* calculate p-1 and q-1 */
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void
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rsa_generate_additional_parameters(RSA *rsa)
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{
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BIGNUM *aux;
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BN_CTX *ctx;
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if ((aux = BN_new()) == NULL)
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fatal("rsa_generate_additional_parameters: BN_new failed");
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if ((ctx = BN_CTX_new()) == NULL)
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fatal("rsa_generate_additional_parameters: BN_CTX_new failed");
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BN_sub(aux, rsa->q, BN_value_one());
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BN_mod(rsa->dmq1, rsa->d, aux, ctx);
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BN_sub(aux, rsa->p, BN_value_one());
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BN_mod(rsa->dmp1, rsa->d, aux, ctx);
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BN_clear_free(aux);
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BN_CTX_free(ctx);
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}
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