257 lines
7.0 KiB
C
257 lines
7.0 KiB
C
/* fips_dsa_sign.c */
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/* Written by Dr Stephen N Henson (steve@openssl.org) for the OpenSSL
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* project 2007.
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*/
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/* ====================================================================
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* Copyright (c) 2007 The OpenSSL Project. 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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* 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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*
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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
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* the documentation and/or other materials provided with the
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* distribution.
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*
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* 3. All advertising materials mentioning features or use of this
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* software must display the following acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
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*
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* 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
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* endorse or promote products derived from this software without
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* prior written permission. For written permission, please contact
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* licensing@OpenSSL.org.
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*
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* 5. Products derived from this software may not be called "OpenSSL"
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* nor may "OpenSSL" appear in their names without prior written
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* permission of the OpenSSL Project.
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*
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* 6. Redistributions of any form whatsoever must retain the following
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* acknowledgment:
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* "This product includes software developed by the OpenSSL Project
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* for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
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*
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* THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
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* EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
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* ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* 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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* This product includes cryptographic software written by Eric Young
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* (eay@cryptsoft.com). This product includes software written by Tim
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* Hudson (tjh@cryptsoft.com).
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*
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*/
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#include <string.h>
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#include <openssl/evp.h>
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#include <openssl/dsa.h>
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#include <openssl/err.h>
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#include <openssl/sha.h>
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#include <openssl/bn.h>
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#ifdef OPENSSL_FIPS
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/* FIPS versions of DSA_sign() and DSA_verify().
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* These include a tiny ASN1 encoder/decoder to handle the specific
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* case of a DSA signature.
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*/
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int FIPS_dsa_size(DSA *r)
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{
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int ilen;
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ilen = BN_num_bytes(r->q);
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if (ilen > 20)
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return -1;
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/* If MSB set need padding byte */
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ilen ++;
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/* Also need 2 bytes INTEGER header for r and s plus
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* 2 bytes SEQUENCE header making 6 in total.
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*/
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return ilen * 2 + 6;
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}
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/* Tiny ASN1 encoder for DSA_SIG structure. We can assume r, s smaller than
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* 0x80 octets as by the DSA standards they will be less than 2^160
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*/
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int FIPS_dsa_sig_encode(unsigned char *out, DSA_SIG *sig)
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{
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int rlen, slen, rpad, spad, seqlen;
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rlen = BN_num_bytes(sig->r);
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if (rlen > 20)
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return -1;
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if (BN_num_bits(sig->r) & 0x7)
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rpad = 0;
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else
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rpad = 1;
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slen = BN_num_bytes(sig->s);
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if (slen > 20)
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return -1;
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if (BN_num_bits(sig->s) & 0x7)
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spad = 0;
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else
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spad = 1;
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/* Length of SEQUENCE, (1 tag + 1 len octet) * 2 + content octets */
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seqlen = rlen + rpad + slen + spad + 4;
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/* Actual encoded length: include SEQUENCE header */
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if (!out)
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return seqlen + 2;
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/* Output SEQUENCE header */
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*out++ = V_ASN1_SEQUENCE|V_ASN1_CONSTRUCTED;
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*out++ = (unsigned char)seqlen;
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/* Output r */
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*out++ = V_ASN1_INTEGER;
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*out++ = (unsigned char)(rlen + rpad);
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if (rpad)
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*out++ = 0;
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BN_bn2bin(sig->r, out);
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out += rlen;
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/* Output s */
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*out++ = V_ASN1_INTEGER;
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*out++ = (unsigned char)(slen + spad);
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if (spad)
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*out++ = 0;
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BN_bn2bin(sig->s, out);
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return seqlen + 2;
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}
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/* Companion DSA_SIG decoder */
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int FIPS_dsa_sig_decode(DSA_SIG *sig, const unsigned char *in, int inlen)
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{
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int seqlen, rlen, slen;
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const unsigned char *rbin;
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/* Sanity check */
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/* Need SEQUENCE tag */
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if (*in++ != (V_ASN1_SEQUENCE|V_ASN1_CONSTRUCTED))
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return 0;
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/* Get length octet */
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seqlen = *in++;
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/* Check sensible length value */
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if (seqlen < 4 || seqlen > 0x7F)
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return 0;
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/* Check INTEGER tag */
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if (*in++ != V_ASN1_INTEGER)
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return 0;
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rlen = *in++;
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seqlen -= 2 + rlen;
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/* Check sensible seqlen value */
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if (seqlen < 2)
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return 0;
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rbin = in;
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in += rlen;
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/* Check INTEGER tag */
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if (*in++ != V_ASN1_INTEGER)
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return 0;
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slen = *in++;
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/* Remaining bytes of SEQUENCE should exactly match
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* encoding of s
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*/
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if (seqlen != (slen + 2))
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return 0;
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if (!sig->r && !(sig->r = BN_new()))
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return 0;
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if (!sig->s && !(sig->s = BN_new()))
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return 0;
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if (!BN_bin2bn(rbin, rlen, sig->r))
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return 0;
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if (!BN_bin2bn(in, slen, sig->s))
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return 0;
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return 1;
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}
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static int fips_dsa_sign(int type, const unsigned char *x, int y,
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unsigned char *sig, unsigned int *siglen, EVP_MD_SVCTX *sv)
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{
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DSA *dsa = sv->key;
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unsigned char dig[EVP_MAX_MD_SIZE];
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unsigned int dlen;
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DSA_SIG *s;
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EVP_DigestFinal_ex(sv->mctx, dig, &dlen);
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s=dsa->meth->dsa_do_sign(dig,dlen,dsa);
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OPENSSL_cleanse(dig, dlen);
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if (s == NULL)
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{
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*siglen=0;
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return 0;
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}
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*siglen= FIPS_dsa_sig_encode(sig, s);
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DSA_SIG_free(s);
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if (*siglen < 0)
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return 0;
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return 1;
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}
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static int fips_dsa_verify(int type, const unsigned char *x, int y,
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const unsigned char *sigbuf, unsigned int siglen, EVP_MD_SVCTX *sv)
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{
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DSA *dsa = sv->key;
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DSA_SIG *s;
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int ret=-1;
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unsigned char dig[EVP_MAX_MD_SIZE];
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unsigned int dlen;
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s = DSA_SIG_new();
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if (s == NULL)
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return ret;
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if (!FIPS_dsa_sig_decode(s,sigbuf,siglen))
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goto err;
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EVP_DigestFinal_ex(sv->mctx, dig, &dlen);
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ret=dsa->meth->dsa_do_verify(dig,dlen,s,dsa);
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OPENSSL_cleanse(dig, dlen);
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err:
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DSA_SIG_free(s);
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return ret;
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}
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static int init(EVP_MD_CTX *ctx)
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{ return SHA1_Init(ctx->md_data); }
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static int update(EVP_MD_CTX *ctx,const void *data,size_t count)
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{ return SHA1_Update(ctx->md_data,data,count); }
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static int final(EVP_MD_CTX *ctx,unsigned char *md)
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{ return SHA1_Final(md,ctx->md_data); }
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static const EVP_MD dss1_md=
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{
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NID_dsa,
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NID_dsaWithSHA1,
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SHA_DIGEST_LENGTH,
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EVP_MD_FLAG_FIPS|EVP_MD_FLAG_SVCTX,
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init,
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update,
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final,
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NULL,
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NULL,
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(evp_sign_method *)fips_dsa_sign,
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(evp_verify_method *)fips_dsa_verify,
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{EVP_PKEY_DSA,EVP_PKEY_DSA2,EVP_PKEY_DSA3, EVP_PKEY_DSA4,0},
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SHA_CBLOCK,
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sizeof(EVP_MD *)+sizeof(SHA_CTX),
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};
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const EVP_MD *EVP_dss1(void)
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{
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return(&dss1_md);
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}
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#endif
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