-/* crypto/dsa/dsa_ossl.c */
-/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
- * All rights reserved.
+/*
+ * Copyright 1995-2016 The OpenSSL Project Authors. 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.]
+ * Licensed under the OpenSSL license (the "License"). You may not use
+ * this file except in compliance with the License. You can obtain a copy
+ * in the file LICENSE in the source distribution or at
+ * https://www.openssl.org/source/license.html
*/
-/* Original version from Steven Schoch <schoch@sheba.arc.nasa.gov> */
-
-#define OPENSSL_FIPSAPI
-
#include <stdio.h>
-#include "cryptlib.h"
+#include "internal/cryptlib.h"
#include <openssl/bn.h>
#include <openssl/sha.h>
-#include <openssl/dsa.h>
-#include <openssl/rand.h>
+#include "dsa_locl.h"
#include <openssl/asn1.h>
-#ifdef OPENSSL_FIPS
-#include <openssl/fips.h>
-#endif
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_sign_setup_no_digest(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp,
+ BIGNUM **rp);
+static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in, BIGNUM **kinvp,
+ BIGNUM **rp, const unsigned char *dgst, int dlen);
+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,
-DSA_FLAG_FIPS_METHOD,
-NULL,
-NULL,
-NULL
+ "OpenSSL DSA method",
+ dsa_do_sign,
+ dsa_sign_setup_no_digest,
+ dsa_do_verify,
+ NULL, /* dsa_mod_exp, */
+ NULL, /* dsa_bn_mod_exp, */
+ dsa_init,
+ dsa_finish,
+ DSA_FLAG_FIPS_METHOD,
+ 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);
- */
+static const DSA_METHOD *default_DSA_method = &openssl_dsa_meth;
-#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)
+void DSA_set_default_method(const DSA_METHOD *meth)
+{
+ default_DSA_method = meth;
+}
+
+const DSA_METHOD *DSA_get_default_method(void)
+{
+ return default_DSA_method;
+}
const DSA_METHOD *DSA_OpenSSL(void)
{
- return &openssl_dsa_meth;
+ 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;
-
-#ifdef OPENSSL_FIPS
- if(FIPS_selftest_failed())
- {
- FIPSerr(FIPS_F_DSA_DO_SIGN,FIPS_R_FIPS_SELFTEST_FAILED);
- return NULL;
- }
-
- if (FIPS_mode() && !(dsa->flags & DSA_FLAG_NON_FIPS_ALLOW)
- && (BN_num_bits(dsa->p) < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
- {
- DSAerr(DSA_F_DSA_DO_SIGN, DSA_R_KEY_SIZE_TOO_SMALL);
- return NULL;
- }
- if (!fips_check_dsa_prng(dsa, 0, 0))
- goto err;
-#endif
-
- 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->meth->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;
- ret=DSA_SIG_new();
- if (ret == NULL) 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->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;
- }
-
-#ifdef OPENSSL_FIPS
- if(FIPS_selftest_failed())
- {
- FIPSerr(FIPS_F_DSA_DO_VERIFY,FIPS_R_FIPS_SELFTEST_FAILED);
- return -1;
- }
-
- if (FIPS_mode() && (BN_num_bits(dsa->p) < OPENSSL_DSA_FIPS_MIN_MODULUS_BITS))
- {
- DSAerr(DSA_F_DSA_DO_VERIFY, DSA_R_KEY_SIZE_TOO_SMALL);
- return -1;
- }
-#endif
-
- 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);
- }
+{
+ BIGNUM *kinv = NULL;
+ BIGNUM *m;
+ BIGNUM *xr;
+ BN_CTX *ctx = NULL;
+ int reason = ERR_R_BN_LIB;
+ DSA_SIG *ret = NULL;
+ int rv = 0;
+
+ m = BN_new();
+ xr = BN_new();
+ if (m == NULL || xr == NULL)
+ goto err;
+
+ if (!dsa->p || !dsa->q || !dsa->g) {
+ reason = DSA_R_MISSING_PARAMETERS;
+ goto err;
+ }
+
+ ret = DSA_SIG_new();
+ if (ret == NULL)
+ goto err;
+ ret->r = BN_new();
+ ret->s = BN_new();
+ if (ret->r == NULL || ret->s == NULL)
+ goto err;
+
+ ctx = BN_CTX_new();
+ if (ctx == NULL)
+ goto err;
+ redo:
+ if (!dsa_sign_setup(dsa, ctx, &kinv, &ret->r, dgst, dlen))
+ goto err;
+
+ 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, ret->r, dsa->q, ctx))
+ goto err; /* s = xr */
+ if (!BN_add(ret->s, xr, m))
+ goto err; /* s = m + xr */
+ if (BN_cmp(ret->s, dsa->q) > 0)
+ if (!BN_sub(ret->s, ret->s, dsa->q))
+ goto err;
+ if (!BN_mod_mul(ret->s, ret->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(ret->r) || BN_is_zero(ret->s))
+ goto redo;
+
+ rv = 1;
+
+ err:
+ if (rv == 0) {
+ DSAerr(DSA_F_DSA_DO_SIGN, reason);
+ DSA_SIG_free(ret);
+ ret = NULL;
+ }
+ BN_CTX_free(ctx);
+ BN_clear_free(m);
+ BN_clear_free(xr);
+ BN_clear_free(kinv);
+ return ret;
+}
+
+static int dsa_sign_setup_no_digest(DSA *dsa, BN_CTX *ctx_in,
+ BIGNUM **kinvp, BIGNUM **rp)
+{
+ return dsa_sign_setup(dsa, ctx_in, kinvp, rp, NULL, 0);
+}
+
+static int dsa_sign_setup(DSA *dsa, BN_CTX *ctx_in,
+ BIGNUM **kinvp, BIGNUM **rp,
+ const unsigned char *dgst, int dlen)
+{
+ BN_CTX *ctx = NULL;
+ BIGNUM *k, *kinv = NULL, *r = *rp;
+ BIGNUM *l, *m;
+ int ret = 0;
+ int q_bits;
+
+ if (!dsa->p || !dsa->q || !dsa->g) {
+ DSAerr(DSA_F_DSA_SIGN_SETUP, DSA_R_MISSING_PARAMETERS);
+ return 0;
+ }
+
+ k = BN_new();
+ l = BN_new();
+ m = BN_new();
+ if (k == NULL || l == NULL || m == NULL)
+ goto err;
+
+ if (ctx_in == NULL) {
+ if ((ctx = BN_CTX_new()) == NULL)
+ goto err;
+ } else
+ ctx = ctx_in;
+
+ /* Preallocate space */
+ q_bits = BN_num_bits(dsa->q);
+ if (!BN_set_bit(k, q_bits)
+ || !BN_set_bit(l, q_bits)
+ || !BN_set_bit(m, q_bits))
+ goto err;
+
+ /* Get random k */
+ do {
+ if (dgst != NULL) {
+ /*
+ * We calculate k from SHA512(private_key + H(message) + random).
+ * This protects the private key from a weak PRNG.
+ */
+ if (!BN_generate_dsa_nonce(k, dsa->q, dsa->priv_key, dgst,
+ dlen, ctx))
+ goto err;
+ } else if (!BN_priv_rand_range(k, dsa->q))
+ goto err;
+ } while (BN_is_zero(k));
+
+ 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,
+ dsa->lock, dsa->p, ctx))
+ goto err;
+ }
+
+ /* Compute r = (g^k mod p) mod q */
+
+ /*
+ * We do not want timing information to leak the length of k, so we
+ * compute G^k using an equivalent scalar of fixed bit-length.
+ *
+ * We unconditionally perform both of these additions to prevent a
+ * small timing information leakage. We then choose the sum that is
+ * one bit longer than the modulus.
+ *
+ * TODO: revisit the BN_copy aiming for a memory access agnostic
+ * conditional copy.
+ */
+ if (!BN_add(l, k, dsa->q)
+ || !BN_add(m, l, dsa->q)
+ || !BN_copy(k, BN_num_bits(l) > q_bits ? l : m))
+ goto err;
+
+ if ((dsa)->meth->bn_mod_exp != NULL) {
+ if (!dsa->meth->bn_mod_exp(dsa, r, dsa->g, k, dsa->p, ctx,
+ dsa->method_mont_p))
+ goto err;
+ } else {
+ if (!BN_mod_exp_mont(r, dsa->g, k, dsa->p, ctx, dsa->method_mont_p))
+ goto err;
+ }
+
+ 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;
+
+ BN_clear_free(*kinvp);
+ *kinvp = kinv;
+ kinv = NULL;
+ ret = 1;
+ err:
+ if (!ret)
+ DSAerr(DSA_F_DSA_SIGN_SETUP, ERR_R_BN_LIB);
+ if (ctx != ctx_in)
+ BN_CTX_free(ctx);
+ BN_clear_free(k);
+ BN_clear_free(l);
+ BN_clear_free(m);
+ 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;
+ const BIGNUM *r, *s;
+ 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;
+ }
+ u1 = BN_new();
+ u2 = BN_new();
+ t1 = BN_new();
+ ctx = BN_CTX_new();
+ if (u1 == NULL || u2 == NULL || t1 == NULL || ctx == NULL)
+ goto err;
+
+ DSA_SIG_get0(sig, &r, &s);
+
+ if (BN_is_zero(r) || BN_is_negative(r) ||
+ BN_ucmp(r, dsa->q) >= 0) {
+ ret = 0;
+ goto err;
+ }
+ if (BN_is_zero(s) || BN_is_negative(s) ||
+ BN_ucmp(s, dsa->q) >= 0) {
+ ret = 0;
+ goto err;
+ }
+
+ /*
+ * Calculate W = inv(S) mod Q save W in u2
+ */
+ if ((BN_mod_inverse(u2, 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, 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,
+ dsa->lock, dsa->p, ctx);
+ if (!mont)
+ goto err;
+ }
+
+ if (dsa->meth->dsa_mod_exp != NULL) {
+ if (!dsa->meth->dsa_mod_exp(dsa, t1, dsa->g, u1, dsa->pub_key, u2,
+ dsa->p, ctx, mont))
+ goto err;
+ } else {
+ if (!BN_mod_exp2_mont(t1, dsa->g, u1, dsa->pub_key, u2, dsa->p, ctx,
+ mont))
+ goto err;
+ }
+
+ /* 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, r) == 0);
+
+ err:
+ if (ret < 0)
+ DSAerr(DSA_F_DSA_DO_VERIFY, ERR_R_BN_LIB);
+ 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);
+ 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);
+ BN_MONT_CTX_free(dsa->method_mont_p);
+ return 1;
}
-
projects / openssl.git / blobdiff