Move ECDSA implementation to crypto/ec

Reviewed-by: Richard Levitte <levitte@openssl.org>

1 files changed, 468 insertions, 0 deletions

diff --git a/crypto/ec/ecdsa_ossl.c b/crypto/ec/ecdsa_ossl.c
new file mode 100644
index 0000000000..bff80f9e11
--- /dev/null
+++ b/crypto/ec/ecdsa_ossl.c
@@ -0,0 +1,468 @@
+/* crypto/ecdsa/ecs_ossl.c */
+/*
+ * Written by Nils Larsch for the OpenSSL project
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2004 The OpenSSL Project.  All rights reserved.
+ *
+ * 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 above 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 acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit. (http://www.OpenSSL.org/)"
+ *
+ * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
+ *    endorse or promote products derived from this software without
+ *    prior written permission. For written permission, please contact
+ *    openssl-core@OpenSSL.org.
+ *
+ * 5. Products derived from this software may not be called "OpenSSL"
+ *    nor may "OpenSSL" appear in their names without prior written
+ *    permission of the OpenSSL Project.
+ *
+ * 6. Redistributions of any form whatsoever must retain the following
+ *    acknowledgment:
+ *    "This product includes software developed by the OpenSSL Project
+ *    for use in the OpenSSL Toolkit (http://www.OpenSSL.org/)"
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
+ * EXPRESSED 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 OpenSSL PROJECT OR
+ * ITS 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.
+ * ====================================================================
+ *
+ * This product includes cryptographic software written by Eric Young
+ * (eay@cryptsoft.com).  This product includes software written by Tim
+ * Hudson (tjh@cryptsoft.com).
+ *
+ */
+
+#include "ecs_locl.h"
+#include <openssl/err.h>
+#include <openssl/obj_mac.h>
+#include <openssl/bn.h>
+#include <openssl/rand.h>
+
+static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dlen,
+                                const BIGNUM *, const BIGNUM *,
+                                EC_KEY *eckey);
+static int ecdsa_sign_setup_no_digest(EC_KEY *eckey, BN_CTX *ctx_in,
+                                      BIGNUM **kinvp, BIGNUM **rp);
+static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in, BIGNUM **kinvp,
+                            BIGNUM **rp, const unsigned char *dgst, int dlen);
+static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
+                           const ECDSA_SIG *sig, EC_KEY *eckey);
+
+static ECDSA_METHOD openssl_ecdsa_meth = {
+    "OpenSSL ECDSA method",
+    ecdsa_do_sign,
+    ecdsa_sign_setup_no_digest,
+    ecdsa_do_verify,
+    ECDSA_FLAG_FIPS_METHOD,     /* flags */
+    NULL                        /* app_data */
+};
+
+const ECDSA_METHOD *ECDSA_OpenSSL(void)
+{
+    return &openssl_ecdsa_meth;
+}
+
+static int ecdsa_sign_setup_no_digest(EC_KEY *eckey,
+                                      BN_CTX *ctx_in, BIGNUM **kinvp,
+                                      BIGNUM **rp)
+{
+    return ecdsa_sign_setup(eckey, ctx_in, kinvp, rp, NULL, 0);
+}
+
+static int ecdsa_sign_setup(EC_KEY *eckey, BN_CTX *ctx_in,
+                            BIGNUM **kinvp, BIGNUM **rp,
+                            const unsigned char *dgst, int dlen)
+{
+    BN_CTX *ctx = NULL;
+    BIGNUM *k = NULL, *r = NULL, *order = NULL, *X = NULL;
+    EC_POINT *tmp_point = NULL;
+    const EC_GROUP *group;
+    int ret = 0;
+
+    if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL) {
+        ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_PASSED_NULL_PARAMETER);
+        return 0;
+    }
+
+    if (ctx_in == NULL) {
+        if ((ctx = BN_CTX_new()) == NULL) {
+            ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
+            return 0;
+        }
+    } else
+        ctx = ctx_in;
+
+    k = BN_new();               /* this value is later returned in *kinvp */
+    r = BN_new();               /* this value is later returned in *rp */
+    order = BN_new();
+    X = BN_new();
+    if (k == NULL || r == NULL || order == NULL || X == NULL) {
+        ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+    if ((tmp_point = EC_POINT_new(group)) == NULL) {
+        ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
+        goto err;
+    }
+    if (!EC_GROUP_get_order(group, order, ctx)) {
+        ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
+        goto err;
+    }
+
+    do {
+        /* get random k */
+        do
+            if (dgst != NULL) {
+                if (!BN_generate_dsa_nonce
+                    (k, order, EC_KEY_get0_private_key(eckey), dgst, dlen,
+                     ctx)) {
+                    ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
+                             ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
+                    goto err;
+                }
+            } else {
+                if (!BN_rand_range(k, order)) {
+                    ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP,
+                             ECDSA_R_RANDOM_NUMBER_GENERATION_FAILED);
+                    goto err;
+                }
+            }
+        while (BN_is_zero(k));
+
+        /*
+         * 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.
+         */
+
+        if (!BN_add(k, k, order))
+            goto err;
+        if (BN_num_bits(k) <= BN_num_bits(order))
+            if (!BN_add(k, k, order))
+                goto err;
+
+        /* compute r the x-coordinate of generator * k */
+        if (!EC_POINT_mul(group, tmp_point, k, NULL, NULL, ctx)) {
+            ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
+            goto err;
+        }
+        if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
+            NID_X9_62_prime_field) {
+            if (!EC_POINT_get_affine_coordinates_GFp
+                (group, tmp_point, X, NULL, ctx)) {
+                ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
+                goto err;
+            }
+        }
+#ifndef OPENSSL_NO_EC2M
+        else {                  /* NID_X9_62_characteristic_two_field */
+
+            if (!EC_POINT_get_affine_coordinates_GF2m(group,
+                                                      tmp_point, X, NULL,
+                                                      ctx)) {
+                ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_EC_LIB);
+                goto err;
+            }
+        }
+#endif
+        if (!BN_nnmod(r, X, order, ctx)) {
+            ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
+            goto err;
+        }
+    }
+    while (BN_is_zero(r));
+
+    /* compute the inverse of k */
+    if (EC_GROUP_get_mont_data(group) != NULL) {
+        /*
+         * We want inverse in constant time, therefore we utilize the fact
+         * order must be prime and use Fermats Little Theorem instead.
+         */
+        if (!BN_set_word(X, 2)) {
+            ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
+            goto err;
+        }
+        if (!BN_mod_sub(X, order, X, order, ctx)) {
+            ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
+            goto err;
+        }
+        BN_set_flags(X, BN_FLG_CONSTTIME);
+        if (!BN_mod_exp_mont_consttime
+            (k, k, X, order, ctx, EC_GROUP_get_mont_data(group))) {
+            ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
+            goto err;
+        }
+    } else {
+        if (!BN_mod_inverse(k, k, order, ctx)) {
+            ECDSAerr(ECDSA_F_ECDSA_SIGN_SETUP, ERR_R_BN_LIB);
+            goto err;
+        }
+    }
+
+    /* clear old values if necessary */
+    BN_clear_free(*rp);
+    BN_clear_free(*kinvp);
+    /* save the pre-computed values  */
+    *rp = r;
+    *kinvp = k;
+    ret = 1;
+ err:
+    if (!ret) {
+        BN_clear_free(k);
+        BN_clear_free(r);
+    }
+    if (ctx != ctx_in)
+        BN_CTX_free(ctx);
+    BN_free(order);
+    EC_POINT_free(tmp_point);
+    BN_clear_free(X);
+    return (ret);
+}
+
+static ECDSA_SIG *ecdsa_do_sign(const unsigned char *dgst, int dgst_len,
+                                const BIGNUM *in_kinv, const BIGNUM *in_r,
+                                EC_KEY *eckey)
+{
+    int ok = 0, i;
+    BIGNUM *kinv = NULL, *s, *m = NULL, *tmp = NULL, *order = NULL;
+    const BIGNUM *ckinv;
+    BN_CTX *ctx = NULL;
+    const EC_GROUP *group;
+    ECDSA_SIG *ret;
+    ECDSA_DATA *ecdsa;
+    const BIGNUM *priv_key;
+
+    ecdsa = ecdsa_check(eckey);
+    group = EC_KEY_get0_group(eckey);
+    priv_key = EC_KEY_get0_private_key(eckey);
+
+    if (group == NULL || priv_key == NULL || ecdsa == NULL) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_PASSED_NULL_PARAMETER);
+        return NULL;
+    }
+
+    ret = ECDSA_SIG_new();
+    if (ret == NULL) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
+        return NULL;
+    }
+    s = ret->s;
+
+    if ((ctx = BN_CTX_new()) == NULL || (order = BN_new()) == NULL ||
+        (tmp = BN_new()) == NULL || (m = BN_new()) == NULL) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    if (!EC_GROUP_get_order(group, order, ctx)) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_EC_LIB);
+        goto err;
+    }
+    i = BN_num_bits(order);
+    /*
+     * Need to truncate digest if it is too long: first truncate whole bytes.
+     */
+    if (8 * dgst_len > i)
+        dgst_len = (i + 7) / 8;
+    if (!BN_bin2bn(dgst, dgst_len, m)) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
+        goto err;
+    }
+    /* If still too long truncate remaining bits with a shift */
+    if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
+        goto err;
+    }
+    do {
+        if (in_kinv == NULL || in_r == NULL) {
+            if (!ecdsa_sign_setup(eckey, ctx, &kinv, &ret->r, dgst, dgst_len)) {
+                ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_ECDSA_LIB);
+                goto err;
+            }
+            ckinv = kinv;
+        } else {
+            ckinv = in_kinv;
+            if (BN_copy(ret->r, in_r) == NULL) {
+                ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_MALLOC_FAILURE);
+                goto err;
+            }
+        }
+
+        if (!BN_mod_mul(tmp, priv_key, ret->r, order, ctx)) {
+            ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
+            goto err;
+        }
+        if (!BN_mod_add_quick(s, tmp, m, order)) {
+            ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
+            goto err;
+        }
+        if (!BN_mod_mul(s, s, ckinv, order, ctx)) {
+            ECDSAerr(ECDSA_F_ECDSA_DO_SIGN, ERR_R_BN_LIB);
+            goto err;
+        }
+        if (BN_is_zero(s)) {
+            /*
+             * if kinv and r have been supplied by the caller don't to
+             * generate new kinv and r values
+             */
+            if (in_kinv != NULL && in_r != NULL) {
+                ECDSAerr(ECDSA_F_ECDSA_DO_SIGN,
+                         ECDSA_R_NEED_NEW_SETUP_VALUES);
+                goto err;
+            }
+        } else
+            /* s != 0 => we have a valid signature */
+            break;
+    }
+    while (1);
+
+    ok = 1;
+ err:
+    if (!ok) {
+        ECDSA_SIG_free(ret);
+        ret = NULL;
+    }
+    BN_CTX_free(ctx);
+    BN_clear_free(m);
+    BN_clear_free(tmp);
+    BN_free(order);
+    BN_clear_free(kinv);
+    return ret;
+}
+
+static int ecdsa_do_verify(const unsigned char *dgst, int dgst_len,
+                           const ECDSA_SIG *sig, EC_KEY *eckey)
+{
+    int ret = -1, i;
+    BN_CTX *ctx;
+    BIGNUM *order, *u1, *u2, *m, *X;
+    EC_POINT *point = NULL;
+    const EC_GROUP *group;
+    const EC_POINT *pub_key;
+
+    /* check input values */
+    if (eckey == NULL || (group = EC_KEY_get0_group(eckey)) == NULL ||
+        (pub_key = EC_KEY_get0_public_key(eckey)) == NULL || sig == NULL) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_MISSING_PARAMETERS);
+        return -1;
+    }
+
+    ctx = BN_CTX_new();
+    if (ctx == NULL) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE);
+        return -1;
+    }
+    BN_CTX_start(ctx);
+    order = BN_CTX_get(ctx);
+    u1 = BN_CTX_get(ctx);
+    u2 = BN_CTX_get(ctx);
+    m = BN_CTX_get(ctx);
+    X = BN_CTX_get(ctx);
+    if (!X) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
+        goto err;
+    }
+
+    if (!EC_GROUP_get_order(group, order, ctx)) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
+        goto err;
+    }
+
+    if (BN_is_zero(sig->r) || BN_is_negative(sig->r) ||
+        BN_ucmp(sig->r, order) >= 0 || BN_is_zero(sig->s) ||
+        BN_is_negative(sig->s) || BN_ucmp(sig->s, order) >= 0) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ECDSA_R_BAD_SIGNATURE);
+        ret = 0;                /* signature is invalid */
+        goto err;
+    }
+    /* calculate tmp1 = inv(S) mod order */
+    if (!BN_mod_inverse(u2, sig->s, order, ctx)) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
+        goto err;
+    }
+    /* digest -> m */
+    i = BN_num_bits(order);
+    /*
+     * Need to truncate digest if it is too long: first truncate whole bytes.
+     */
+    if (8 * dgst_len > i)
+        dgst_len = (i + 7) / 8;
+    if (!BN_bin2bn(dgst, dgst_len, m)) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
+        goto err;
+    }
+    /* If still too long truncate remaining bits with a shift */
+    if ((8 * dgst_len > i) && !BN_rshift(m, m, 8 - (i & 0x7))) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
+        goto err;
+    }
+    /* u1 = m * tmp mod order */
+    if (!BN_mod_mul(u1, m, u2, order, ctx)) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
+        goto err;
+    }
+    /* u2 = r * w mod q */
+    if (!BN_mod_mul(u2, sig->r, u2, order, ctx)) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
+        goto err;
+    }
+
+    if ((point = EC_POINT_new(group)) == NULL) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+    if (!EC_POINT_mul(group, point, u1, pub_key, u2, ctx)) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
+        goto err;
+    }
+    if (EC_METHOD_get_field_type(EC_GROUP_method_of(group)) ==
+        NID_X9_62_prime_field) {
+        if (!EC_POINT_get_affine_coordinates_GFp(group, point, X, NULL, ctx)) {
+            ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
+            goto err;
+        }
+    }
+#ifndef OPENSSL_NO_EC2M
+    else {                      /* NID_X9_62_characteristic_two_field */
+
+        if (!EC_POINT_get_affine_coordinates_GF2m(group, point, X, NULL, ctx)) {
+            ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_EC_LIB);
+            goto err;
+        }
+    }
+#endif
+    if (!BN_nnmod(u1, X, order, ctx)) {
+        ECDSAerr(ECDSA_F_ECDSA_DO_VERIFY, ERR_R_BN_LIB);
+        goto err;
+    }
+    /*  if the signature is correct u1 is equal to sig->r */
+    ret = (BN_ucmp(u1, sig->r) == 0);
+ err:
+    BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+    EC_POINT_free(point);
+    return ret;
+}