diff options
Diffstat (limited to 'openssl/crypto/dsa/dsa_ossl.c')
| -rw-r--r-- | openssl/crypto/dsa/dsa_ossl.c | 427 |
1 files changed, 427 insertions, 0 deletions
diff --git a/openssl/crypto/dsa/dsa_ossl.c b/openssl/crypto/dsa/dsa_ossl.c new file mode 100644 index 0000000..58013a4 --- /dev/null +++ b/openssl/crypto/dsa/dsa_ossl.c @@ -0,0 +1,427 @@ +/* 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; + int noredo = 0; + + 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; + redo: + 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; + noredo = 1; + } + + 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; + + /* + * Redo if r or s is zero as required by FIPS 186-3: this is very + * unlikely. + */ + if (BN_is_zero(r) || BN_is_zero(s)) { + if (noredo) { + reason = DSA_R_NEED_NEW_SETUP_VALUES; + goto err; + } + goto redo; + } + ret = DSA_SIG_new(); + if (ret == NULL) + goto err; + ret->r = r; + ret->s = s; + + err: + if (ret == NULL) { + 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; + + BN_set_flags(&kq, BN_FLG_CONSTTIME); + + /* + * 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: + if (ret < 0) + 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); +} |