diff options
Diffstat (limited to 'openssl/crypto/dsa/dsa_ossl.c')
| -rw-r--r-- | openssl/crypto/dsa/dsa_ossl.c | 398 |
1 files changed, 398 insertions, 0 deletions
diff --git a/openssl/crypto/dsa/dsa_ossl.c b/openssl/crypto/dsa/dsa_ossl.c new file mode 100644 index 00000000..a3ddd7d2 --- /dev/null +++ b/openssl/crypto/dsa/dsa_ossl.c @@ -0,0 +1,398 @@ +/* crypto/dsa/dsa_ossl.c */ +/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) + * All rights reserved. + * + * This package is an SSL implementation written + * by Eric Young (eay@cryptsoft.com). + * The implementation was written so as to conform with Netscapes SSL. + * + * This library is free for commercial and non-commercial use as long as + * the following conditions are aheared to. The following conditions + * apply to all code found in this distribution, be it the RC4, RSA, + * lhash, DES, etc., code; not just the SSL code. The SSL documentation + * included with this distribution is covered by the same copyright terms + * except that the holder is Tim Hudson (tjh@cryptsoft.com). + * + * Copyright remains Eric Young's, and as such any Copyright notices in + * the code are not to be removed. + * If this package is used in a product, Eric Young should be given attribution + * as the author of the parts of the library used. + * This can be in the form of a textual message at program startup or + * in documentation (online or textual) provided with the package. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. All advertising materials mentioning features or use of this software + * must display the following acknowledgement: + * "This product includes cryptographic software written by + * Eric Young (eay@cryptsoft.com)" + * The word 'cryptographic' can be left out if the rouines from the library + * being used are not cryptographic related :-). + * 4. If you include any Windows specific code (or a derivative thereof) from + * the apps directory (application code) you must include an acknowledgement: + * "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" + * + * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + * + * The licence and distribution terms for any publically available version or + * derivative of this code cannot be changed. i.e. this code cannot simply be + * copied and put under another distribution licence + * [including the GNU Public Licence.] + */ + +/* Original version from Steven Schoch <schoch@sheba.arc.nasa.gov> */ + +#include <stdio.h> +#include "cryptlib.h" +#include <openssl/bn.h> +#include <openssl/sha.h> +#include <openssl/dsa.h> +#include <openssl/rand.h> +#include <openssl/asn1.h> + +static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa); +static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp); +static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, + DSA *dsa); +static int dsa_init(DSA *dsa); +static int dsa_finish(DSA *dsa); + +static DSA_METHOD openssl_dsa_meth = { +"OpenSSL DSA method", +dsa_do_sign, +dsa_sign_setup, +dsa_do_verify, +NULL, /* dsa_mod_exp, */ +NULL, /* dsa_bn_mod_exp, */ +dsa_init, +dsa_finish, +0, +NULL, +NULL, +NULL +}; + +/* These macro wrappers replace attempts to use the dsa_mod_exp() and + * bn_mod_exp() handlers in the DSA_METHOD structure. We avoid the problem of + * having a the macro work as an expression by bundling an "err_instr". So; + * + * if (!dsa->meth->bn_mod_exp(dsa, r,dsa->g,&k,dsa->p,ctx, + * dsa->method_mont_p)) goto err; + * + * can be replaced by; + * + * DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, &k, dsa->p, ctx, + * dsa->method_mont_p); + */ + +#define DSA_MOD_EXP(err_instr,dsa,rr,a1,p1,a2,p2,m,ctx,in_mont) \ + do { \ + int _tmp_res53; \ + if((dsa)->meth->dsa_mod_exp) \ + _tmp_res53 = (dsa)->meth->dsa_mod_exp((dsa), (rr), (a1), (p1), \ + (a2), (p2), (m), (ctx), (in_mont)); \ + else \ + _tmp_res53 = BN_mod_exp2_mont((rr), (a1), (p1), (a2), (p2), \ + (m), (ctx), (in_mont)); \ + if(!_tmp_res53) err_instr; \ + } while(0) +#define DSA_BN_MOD_EXP(err_instr,dsa,r,a,p,m,ctx,m_ctx) \ + do { \ + int _tmp_res53; \ + if((dsa)->meth->bn_mod_exp) \ + _tmp_res53 = (dsa)->meth->bn_mod_exp((dsa), (r), (a), (p), \ + (m), (ctx), (m_ctx)); \ + else \ + _tmp_res53 = BN_mod_exp_mont((r), (a), (p), (m), (ctx), (m_ctx)); \ + if(!_tmp_res53) err_instr; \ + } while(0) + +const DSA_METHOD *DSA_OpenSSL(void) +{ + return &openssl_dsa_meth; +} + +static DSA_SIG *dsa_do_sign(const unsigned char *dgst, int dlen, DSA *dsa) + { + BIGNUM *kinv=NULL,*r=NULL,*s=NULL; + BIGNUM m; + BIGNUM xr; + BN_CTX *ctx=NULL; + int reason=ERR_R_BN_LIB; + DSA_SIG *ret=NULL; + + BN_init(&m); + BN_init(&xr); + + if (!dsa->p || !dsa->q || !dsa->g) + { + reason=DSA_R_MISSING_PARAMETERS; + goto err; + } + + s=BN_new(); + if (s == NULL) goto err; + ctx=BN_CTX_new(); + if (ctx == NULL) goto err; + + if ((dsa->kinv == NULL) || (dsa->r == NULL)) + { + if (!DSA_sign_setup(dsa,ctx,&kinv,&r)) goto err; + } + else + { + kinv=dsa->kinv; + dsa->kinv=NULL; + r=dsa->r; + dsa->r=NULL; + } + + + if (dlen > BN_num_bytes(dsa->q)) + /* if the digest length is greater than the size of q use the + * BN_num_bits(dsa->q) leftmost bits of the digest, see + * fips 186-3, 4.2 */ + dlen = BN_num_bytes(dsa->q); + if (BN_bin2bn(dgst,dlen,&m) == NULL) + goto err; + + /* Compute s = inv(k) (m + xr) mod q */ + if (!BN_mod_mul(&xr,dsa->priv_key,r,dsa->q,ctx)) goto err;/* s = xr */ + if (!BN_add(s, &xr, &m)) goto err; /* s = m + xr */ + if (BN_cmp(s,dsa->q) > 0) + if (!BN_sub(s,s,dsa->q)) goto err; + if (!BN_mod_mul(s,s,kinv,dsa->q,ctx)) goto err; + + ret=DSA_SIG_new(); + if (ret == NULL) goto err; + ret->r = r; + ret->s = s; + +err: + if (!ret) + { + DSAerr(DSA_F_DSA_DO_SIGN,reason); + BN_free(r); + BN_free(s); + } + if (ctx != NULL) BN_CTX_free(ctx); + BN_clear_free(&m); + BN_clear_free(&xr); + if (kinv != NULL) /* dsa->kinv is NULL now if we used it */ + BN_clear_free(kinv); + return(ret); + } + +static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp, BIGNUM **rp) + { + BN_CTX *ctx; + BIGNUM k,kq,*K,*kinv=NULL,*r=NULL; + int ret=0; + + if (!dsa->p || !dsa->q || !dsa->g) + { + DSAerr(DSA_F_DSA_SIGN_SETUP,DSA_R_MISSING_PARAMETERS); + return 0; + } + + BN_init(&k); + BN_init(&kq); + + if (ctx_in == NULL) + { + if ((ctx=BN_CTX_new()) == NULL) goto err; + } + else + ctx=ctx_in; + + if ((r=BN_new()) == NULL) goto err; + + /* Get random k */ + do + if (!BN_rand_range(&k, dsa->q)) goto err; + while (BN_is_zero(&k)); + if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) + { + BN_set_flags(&k, BN_FLG_CONSTTIME); + } + + if (dsa->flags & DSA_FLAG_CACHE_MONT_P) + { + if (!BN_MONT_CTX_set_locked(&dsa->method_mont_p, + CRYPTO_LOCK_DSA, + dsa->p, ctx)) + goto err; + } + + /* Compute r = (g^k mod p) mod q */ + + if ((dsa->flags & DSA_FLAG_NO_EXP_CONSTTIME) == 0) + { + if (!BN_copy(&kq, &k)) goto err; + + /* We do not want timing information to leak the length of k, + * so we compute g^k using an equivalent exponent of fixed length. + * + * (This is a kludge that we need because the BN_mod_exp_mont() + * does not let us specify the desired timing behaviour.) */ + + if (!BN_add(&kq, &kq, dsa->q)) goto err; + if (BN_num_bits(&kq) <= BN_num_bits(dsa->q)) + { + if (!BN_add(&kq, &kq, dsa->q)) goto err; + } + + K = &kq; + } + else + { + K = &k; + } + DSA_BN_MOD_EXP(goto err, dsa, r, dsa->g, K, dsa->p, ctx, + dsa->method_mont_p); + if (!BN_mod(r,r,dsa->q,ctx)) goto err; + + /* Compute part of 's = inv(k) (m + xr) mod q' */ + if ((kinv=BN_mod_inverse(NULL,&k,dsa->q,ctx)) == NULL) goto err; + + if (*kinvp != NULL) BN_clear_free(*kinvp); + *kinvp=kinv; + kinv=NULL; + if (*rp != NULL) BN_clear_free(*rp); + *rp=r; + ret=1; +err: + if (!ret) + { + DSAerr(DSA_F_DSA_SIGN_SETUP,ERR_R_BN_LIB); + if (r != NULL) + BN_clear_free(r); + } + if (ctx_in == NULL) BN_CTX_free(ctx); + BN_clear_free(&k); + BN_clear_free(&kq); + return(ret); + } + +static int dsa_do_verify(const unsigned char *dgst, int dgst_len, DSA_SIG *sig, + DSA *dsa) + { + BN_CTX *ctx; + BIGNUM u1,u2,t1; + BN_MONT_CTX *mont=NULL; + int ret = -1, i; + if (!dsa->p || !dsa->q || !dsa->g) + { + DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MISSING_PARAMETERS); + return -1; + } + + i = BN_num_bits(dsa->q); + /* fips 186-3 allows only different sizes for q */ + if (i != 160 && i != 224 && i != 256) + { + DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_BAD_Q_VALUE); + return -1; + } + + if (BN_num_bits(dsa->p) > OPENSSL_DSA_MAX_MODULUS_BITS) + { + DSAerr(DSA_F_DSA_DO_VERIFY,DSA_R_MODULUS_TOO_LARGE); + return -1; + } + BN_init(&u1); + BN_init(&u2); + BN_init(&t1); + + if ((ctx=BN_CTX_new()) == NULL) goto err; + + if (BN_is_zero(sig->r) || BN_is_negative(sig->r) || + BN_ucmp(sig->r, dsa->q) >= 0) + { + ret = 0; + goto err; + } + if (BN_is_zero(sig->s) || BN_is_negative(sig->s) || + BN_ucmp(sig->s, dsa->q) >= 0) + { + ret = 0; + goto err; + } + + /* Calculate W = inv(S) mod Q + * save W in u2 */ + if ((BN_mod_inverse(&u2,sig->s,dsa->q,ctx)) == NULL) goto err; + + /* save M in u1 */ + if (dgst_len > (i >> 3)) + /* if the digest length is greater than the size of q use the + * BN_num_bits(dsa->q) leftmost bits of the digest, see + * fips 186-3, 4.2 */ + dgst_len = (i >> 3); + if (BN_bin2bn(dgst,dgst_len,&u1) == NULL) goto err; + + /* u1 = M * w mod q */ + if (!BN_mod_mul(&u1,&u1,&u2,dsa->q,ctx)) goto err; + + /* u2 = r * w mod q */ + if (!BN_mod_mul(&u2,sig->r,&u2,dsa->q,ctx)) goto err; + + + if (dsa->flags & DSA_FLAG_CACHE_MONT_P) + { + mont = BN_MONT_CTX_set_locked(&dsa->method_mont_p, + CRYPTO_LOCK_DSA, dsa->p, ctx); + if (!mont) + goto err; + } + + + DSA_MOD_EXP(goto err, dsa, &t1, dsa->g, &u1, dsa->pub_key, &u2, dsa->p, ctx, mont); + /* BN_copy(&u1,&t1); */ + /* let u1 = u1 mod q */ + if (!BN_mod(&u1,&t1,dsa->q,ctx)) goto err; + + /* V is now in u1. If the signature is correct, it will be + * equal to R. */ + ret=(BN_ucmp(&u1, sig->r) == 0); + + err: + /* XXX: surely this is wrong - if ret is 0, it just didn't verify; + there is no error in BN. Test should be ret == -1 (Ben) */ + if (ret != 1) DSAerr(DSA_F_DSA_DO_VERIFY,ERR_R_BN_LIB); + if (ctx != NULL) BN_CTX_free(ctx); + BN_free(&u1); + BN_free(&u2); + BN_free(&t1); + return(ret); + } + +static int dsa_init(DSA *dsa) +{ + dsa->flags|=DSA_FLAG_CACHE_MONT_P; + return(1); +} + +static int dsa_finish(DSA *dsa) +{ + if(dsa->method_mont_p) + BN_MONT_CTX_free(dsa->method_mont_p); + return(1); +} + |