Rename RSA_eay_xxx to rsa_ossl_xxx

Final part of flushing out SSLEay API's.

Reviewed-by: Tim Hudson <tjh@openssl.org>

1 files changed, 921 insertions, 0 deletions

diff --git a/crypto/rsa/rsa_ossl.c b/crypto/rsa/rsa_ossl.c
new file mode 100644
index 0000000000..09a65b80b1
--- /dev/null
+++ b/crypto/rsa/rsa_ossl.c
@@ -0,0 +1,921 @@
+/* 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.]
+ */
+/* ====================================================================
+ * Copyright (c) 1998-2006 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 "internal/cryptlib.h"
+#include "internal/bn_int.h"
+#include <openssl/rsa.h>
+#include <openssl/rand.h>
+
+#ifndef RSA_NULL
+
+static int rsa_ossl_public_encrypt(int flen, const unsigned char *from,
+                                  unsigned char *to, RSA *rsa, int padding);
+static int rsa_ossl_private_encrypt(int flen, const unsigned char *from,
+                                   unsigned char *to, RSA *rsa, int padding);
+static int rsa_ossl_public_decrypt(int flen, const unsigned char *from,
+                                  unsigned char *to, RSA *rsa, int padding);
+static int rsa_ossl_private_decrypt(int flen, const unsigned char *from,
+                                   unsigned char *to, RSA *rsa, int padding);
+static int rsa_ossl_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa,
+                           BN_CTX *ctx);
+static int rsa_ossl_init(RSA *rsa);
+static int rsa_ossl_finish(RSA *rsa);
+static RSA_METHOD rsa_pkcs1_ossl_meth = {
+    "OpenSSL PKCS#1 RSA (from Eric Young)",
+    rsa_ossl_public_encrypt,
+    rsa_ossl_public_decrypt,     /* signature verification */
+    rsa_ossl_private_encrypt,    /* signing */
+    rsa_ossl_private_decrypt,
+    rsa_ossl_mod_exp,
+    BN_mod_exp_mont,            /* XXX probably we should not use Montgomery
+                                 * if e == 3 */
+    rsa_ossl_init,
+    rsa_ossl_finish,
+    RSA_FLAG_FIPS_METHOD,       /* flags */
+    NULL,
+    0,                          /* rsa_sign */
+    0,                          /* rsa_verify */
+    NULL                        /* rsa_keygen */
+};
+
+const RSA_METHOD *RSA_PKCS1_OpenSSL(void)
+{
+    return &rsa_pkcs1_ossl_meth;
+}
+
+static int rsa_ossl_public_encrypt(int flen, const unsigned char *from,
+                                  unsigned char *to, RSA *rsa, int padding)
+{
+    BIGNUM *f, *ret;
+    int i, j, k, num = 0, r = -1;
+    unsigned char *buf = NULL;
+    BN_CTX *ctx = NULL;
+
+    if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) {
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_ENCRYPT, RSA_R_MODULUS_TOO_LARGE);
+        return -1;
+    }
+
+    if (BN_ucmp(rsa->n, rsa->e) <= 0) {
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
+        return -1;
+    }
+
+    /* for large moduli, enforce exponent limit */
+    if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) {
+        if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) {
+            RSAerr(RSA_F_RSA_OSSL_PUBLIC_ENCRYPT, RSA_R_BAD_E_VALUE);
+            return -1;
+        }
+    }
+
+    if ((ctx = BN_CTX_new()) == NULL)
+        goto err;
+    BN_CTX_start(ctx);
+    f = BN_CTX_get(ctx);
+    ret = BN_CTX_get(ctx);
+    num = BN_num_bytes(rsa->n);
+    buf = OPENSSL_malloc(num);
+    if (f == NULL || ret == NULL || buf == NULL) {
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_ENCRYPT, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    switch (padding) {
+    case RSA_PKCS1_PADDING:
+        i = RSA_padding_add_PKCS1_type_2(buf, num, from, flen);
+        break;
+    case RSA_PKCS1_OAEP_PADDING:
+        i = RSA_padding_add_PKCS1_OAEP(buf, num, from, flen, NULL, 0);
+        break;
+    case RSA_SSLV23_PADDING:
+        i = RSA_padding_add_SSLv23(buf, num, from, flen);
+        break;
+    case RSA_NO_PADDING:
+        i = RSA_padding_add_none(buf, num, from, flen);
+        break;
+    default:
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
+        goto err;
+    }
+    if (i <= 0)
+        goto err;
+
+    if (BN_bin2bn(buf, num, f) == NULL)
+        goto err;
+
+    if (BN_ucmp(f, rsa->n) >= 0) {
+        /* usually the padding functions would catch this */
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_ENCRYPT,
+               RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+        goto err;
+    }
+
+    if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
+        if (!BN_MONT_CTX_set_locked
+            (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
+            goto err;
+
+    if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx,
+                               rsa->_method_mod_n))
+        goto err;
+
+    /*
+     * put in leading 0 bytes if the number is less than the length of the
+     * modulus
+     */
+    j = BN_num_bytes(ret);
+    i = BN_bn2bin(ret, &(to[num - j]));
+    for (k = 0; k < (num - i); k++)
+        to[k] = 0;
+
+    r = num;
+ err:
+    if (ctx != NULL)
+        BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+    OPENSSL_clear_free(buf, num);
+    return (r);
+}
+
+static BN_BLINDING *rsa_get_blinding(RSA *rsa, int *local, BN_CTX *ctx)
+{
+    BN_BLINDING *ret;
+    int got_write_lock = 0;
+    CRYPTO_THREADID cur;
+
+    CRYPTO_r_lock(CRYPTO_LOCK_RSA);
+
+    if (rsa->blinding == NULL) {
+        CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+        CRYPTO_w_lock(CRYPTO_LOCK_RSA);
+        got_write_lock = 1;
+
+        if (rsa->blinding == NULL)
+            rsa->blinding = RSA_setup_blinding(rsa, ctx);
+    }
+
+    ret = rsa->blinding;
+    if (ret == NULL)
+        goto err;
+
+    CRYPTO_THREADID_current(&cur);
+    if (!CRYPTO_THREADID_cmp(&cur, BN_BLINDING_thread_id(ret))) {
+        /* rsa->blinding is ours! */
+
+        *local = 1;
+    } else {
+        /* resort to rsa->mt_blinding instead */
+
+        /*
+         * instructs rsa_blinding_convert(), rsa_blinding_invert() that the
+         * BN_BLINDING is shared, meaning that accesses require locks, and
+         * that the blinding factor must be stored outside the BN_BLINDING
+         */
+        *local = 0;
+
+        if (rsa->mt_blinding == NULL) {
+            if (!got_write_lock) {
+                CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+                CRYPTO_w_lock(CRYPTO_LOCK_RSA);
+                got_write_lock = 1;
+            }
+
+            if (rsa->mt_blinding == NULL)
+                rsa->mt_blinding = RSA_setup_blinding(rsa, ctx);
+        }
+        ret = rsa->mt_blinding;
+    }
+
+ err:
+    if (got_write_lock)
+        CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
+    else
+        CRYPTO_r_unlock(CRYPTO_LOCK_RSA);
+    return ret;
+}
+
+static int rsa_blinding_convert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
+                                BN_CTX *ctx)
+{
+    if (unblind == NULL)
+        /*
+         * Local blinding: store the unblinding factor in BN_BLINDING.
+         */
+        return BN_BLINDING_convert_ex(f, NULL, b, ctx);
+    else {
+        /*
+         * Shared blinding: store the unblinding factor outside BN_BLINDING.
+         */
+        int ret;
+        CRYPTO_w_lock(CRYPTO_LOCK_RSA_BLINDING);
+        ret = BN_BLINDING_convert_ex(f, unblind, b, ctx);
+        CRYPTO_w_unlock(CRYPTO_LOCK_RSA_BLINDING);
+        return ret;
+    }
+}
+
+static int rsa_blinding_invert(BN_BLINDING *b, BIGNUM *f, BIGNUM *unblind,
+                               BN_CTX *ctx)
+{
+    /*
+     * For local blinding, unblind is set to NULL, and BN_BLINDING_invert_ex
+     * will use the unblinding factor stored in BN_BLINDING. If BN_BLINDING
+     * is shared between threads, unblind must be non-null:
+     * BN_BLINDING_invert_ex will then use the local unblinding factor, and
+     * will only read the modulus from BN_BLINDING. In both cases it's safe
+     * to access the blinding without a lock.
+     */
+    return BN_BLINDING_invert_ex(f, unblind, b, ctx);
+}
+
+/* signing */
+static int rsa_ossl_private_encrypt(int flen, const unsigned char *from,
+                                   unsigned char *to, RSA *rsa, int padding)
+{
+    BIGNUM *f, *ret, *res;
+    int i, j, k, num = 0, r = -1;
+    unsigned char *buf = NULL;
+    BN_CTX *ctx = NULL;
+    int local_blinding = 0;
+    /*
+     * Used only if the blinding structure is shared. A non-NULL unblind
+     * instructs rsa_blinding_convert() and rsa_blinding_invert() to store
+     * the unblinding factor outside the blinding structure.
+     */
+    BIGNUM *unblind = NULL;
+    BN_BLINDING *blinding = NULL;
+
+    if ((ctx = BN_CTX_new()) == NULL)
+        goto err;
+    BN_CTX_start(ctx);
+    f = BN_CTX_get(ctx);
+    ret = BN_CTX_get(ctx);
+    num = BN_num_bytes(rsa->n);
+    buf = OPENSSL_malloc(num);
+    if (f == NULL || ret == NULL || buf == NULL) {
+        RSAerr(RSA_F_RSA_OSSL_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    switch (padding) {
+    case RSA_PKCS1_PADDING:
+        i = RSA_padding_add_PKCS1_type_1(buf, num, from, flen);
+        break;
+    case RSA_X931_PADDING:
+        i = RSA_padding_add_X931(buf, num, from, flen);
+        break;
+    case RSA_NO_PADDING:
+        i = RSA_padding_add_none(buf, num, from, flen);
+        break;
+    case RSA_SSLV23_PADDING:
+    default:
+        RSAerr(RSA_F_RSA_OSSL_PRIVATE_ENCRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
+        goto err;
+    }
+    if (i <= 0)
+        goto err;
+
+    if (BN_bin2bn(buf, num, f) == NULL)
+        goto err;
+
+    if (BN_ucmp(f, rsa->n) >= 0) {
+        /* usually the padding functions would catch this */
+        RSAerr(RSA_F_RSA_OSSL_PRIVATE_ENCRYPT,
+               RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+        goto err;
+    }
+
+    if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) {
+        blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
+        if (blinding == NULL) {
+            RSAerr(RSA_F_RSA_OSSL_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
+    }
+
+    if (blinding != NULL) {
+        if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) {
+            RSAerr(RSA_F_RSA_OSSL_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
+            goto err;
+        }
+        if (!rsa_blinding_convert(blinding, f, unblind, ctx))
+            goto err;
+    }
+
+    if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
+        ((rsa->p != NULL) &&
+         (rsa->q != NULL) &&
+         (rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) {
+        if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx))
+            goto err;
+    } else {
+        BIGNUM *d = NULL, *local_d = NULL;
+
+        if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+            local_d = d = BN_new();
+            if (d == NULL) {
+                RSAerr(RSA_F_RSA_OSSL_PRIVATE_ENCRYPT, ERR_R_MALLOC_FAILURE);
+                goto err;
+            }
+            BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
+        } else
+            d = rsa->d;
+
+        if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
+            if (!BN_MONT_CTX_set_locked
+                (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx)) {
+                BN_free(local_d);
+                goto err;
+            }
+
+        if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx,
+                                   rsa->_method_mod_n)) {
+            BN_free(local_d);
+            goto err;
+        }
+        BN_free(local_d);
+    }
+
+    if (blinding)
+        if (!rsa_blinding_invert(blinding, ret, unblind, ctx))
+            goto err;
+
+    if (padding == RSA_X931_PADDING) {
+        BN_sub(f, rsa->n, ret);
+        if (BN_cmp(ret, f) > 0)
+            res = f;
+        else
+            res = ret;
+    } else
+        res = ret;
+
+    /*
+     * put in leading 0 bytes if the number is less than the length of the
+     * modulus
+     */
+    j = BN_num_bytes(res);
+    i = BN_bn2bin(res, &(to[num - j]));
+    for (k = 0; k < (num - i); k++)
+        to[k] = 0;
+
+    r = num;
+ err:
+    if (ctx != NULL)
+        BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+    OPENSSL_clear_free(buf, num);
+    return (r);
+}
+
+static int rsa_ossl_private_decrypt(int flen, const unsigned char *from,
+                                   unsigned char *to, RSA *rsa, int padding)
+{
+    BIGNUM *f, *ret;
+    int j, num = 0, r = -1;
+    unsigned char *p;
+    unsigned char *buf = NULL;
+    BN_CTX *ctx = NULL;
+    int local_blinding = 0;
+    /*
+     * Used only if the blinding structure is shared. A non-NULL unblind
+     * instructs rsa_blinding_convert() and rsa_blinding_invert() to store
+     * the unblinding factor outside the blinding structure.
+     */
+    BIGNUM *unblind = NULL;
+    BN_BLINDING *blinding = NULL;
+
+    if ((ctx = BN_CTX_new()) == NULL)
+        goto err;
+    BN_CTX_start(ctx);
+    f = BN_CTX_get(ctx);
+    ret = BN_CTX_get(ctx);
+    num = BN_num_bytes(rsa->n);
+    buf = OPENSSL_malloc(num);
+    if (f == NULL || ret == NULL || buf == NULL) {
+        RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    /*
+     * This check was for equality but PGP does evil things and chops off the
+     * top '0' bytes
+     */
+    if (flen > num) {
+        RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT,
+               RSA_R_DATA_GREATER_THAN_MOD_LEN);
+        goto err;
+    }
+
+    /* make data into a big number */
+    if (BN_bin2bn(from, (int)flen, f) == NULL)
+        goto err;
+
+    if (BN_ucmp(f, rsa->n) >= 0) {
+        RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT,
+               RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+        goto err;
+    }
+
+    if (!(rsa->flags & RSA_FLAG_NO_BLINDING)) {
+        blinding = rsa_get_blinding(rsa, &local_blinding, ctx);
+        if (blinding == NULL) {
+            RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
+            goto err;
+        }
+    }
+
+    if (blinding != NULL) {
+        if (!local_blinding && ((unblind = BN_CTX_get(ctx)) == NULL)) {
+            RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
+            goto err;
+        }
+        if (!rsa_blinding_convert(blinding, f, unblind, ctx))
+            goto err;
+    }
+
+    /* do the decrypt */
+    if ((rsa->flags & RSA_FLAG_EXT_PKEY) ||
+        ((rsa->p != NULL) &&
+         (rsa->q != NULL) &&
+         (rsa->dmp1 != NULL) && (rsa->dmq1 != NULL) && (rsa->iqmp != NULL))) {
+        if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx))
+            goto err;
+    } else {
+        BIGNUM *d = NULL, *local_d = NULL;
+
+        if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+            local_d = d = BN_new();
+            if (d == NULL) {
+                RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, ERR_R_MALLOC_FAILURE);
+                goto err;
+            }
+            BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
+        } else
+            d = rsa->d;
+
+        if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
+            if (!BN_MONT_CTX_set_locked
+                (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx)) {
+                BN_free(local_d);
+                goto err;
+            }
+        if (!rsa->meth->bn_mod_exp(ret, f, d, rsa->n, ctx,
+                                   rsa->_method_mod_n)) {
+            BN_free(local_d);
+            goto err;
+        }
+        BN_free(local_d);
+    }
+
+    if (blinding)
+        if (!rsa_blinding_invert(blinding, ret, unblind, ctx))
+            goto err;
+
+    p = buf;
+    j = BN_bn2bin(ret, p);      /* j is only used with no-padding mode */
+
+    switch (padding) {
+    case RSA_PKCS1_PADDING:
+        r = RSA_padding_check_PKCS1_type_2(to, num, buf, j, num);
+        break;
+    case RSA_PKCS1_OAEP_PADDING:
+        r = RSA_padding_check_PKCS1_OAEP(to, num, buf, j, num, NULL, 0);
+        break;
+    case RSA_SSLV23_PADDING:
+        r = RSA_padding_check_SSLv23(to, num, buf, j, num);
+        break;
+    case RSA_NO_PADDING:
+        r = RSA_padding_check_none(to, num, buf, j, num);
+        break;
+    default:
+        RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
+        goto err;
+    }
+    if (r < 0)
+        RSAerr(RSA_F_RSA_OSSL_PRIVATE_DECRYPT, RSA_R_PADDING_CHECK_FAILED);
+
+ err:
+    if (ctx != NULL)
+        BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+    OPENSSL_clear_free(buf, num);
+    return (r);
+}
+
+/* signature verification */
+static int rsa_ossl_public_decrypt(int flen, const unsigned char *from,
+                                  unsigned char *to, RSA *rsa, int padding)
+{
+    BIGNUM *f, *ret;
+    int i, num = 0, r = -1;
+    unsigned char *p;
+    unsigned char *buf = NULL;
+    BN_CTX *ctx = NULL;
+
+    if (BN_num_bits(rsa->n) > OPENSSL_RSA_MAX_MODULUS_BITS) {
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_DECRYPT, RSA_R_MODULUS_TOO_LARGE);
+        return -1;
+    }
+
+    if (BN_ucmp(rsa->n, rsa->e) <= 0) {
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
+        return -1;
+    }
+
+    /* for large moduli, enforce exponent limit */
+    if (BN_num_bits(rsa->n) > OPENSSL_RSA_SMALL_MODULUS_BITS) {
+        if (BN_num_bits(rsa->e) > OPENSSL_RSA_MAX_PUBEXP_BITS) {
+            RSAerr(RSA_F_RSA_OSSL_PUBLIC_DECRYPT, RSA_R_BAD_E_VALUE);
+            return -1;
+        }
+    }
+
+    if ((ctx = BN_CTX_new()) == NULL)
+        goto err;
+    BN_CTX_start(ctx);
+    f = BN_CTX_get(ctx);
+    ret = BN_CTX_get(ctx);
+    num = BN_num_bytes(rsa->n);
+    buf = OPENSSL_malloc(num);
+    if (f == NULL || ret == NULL || buf == NULL) {
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_DECRYPT, ERR_R_MALLOC_FAILURE);
+        goto err;
+    }
+
+    /*
+     * This check was for equality but PGP does evil things and chops off the
+     * top '0' bytes
+     */
+    if (flen > num) {
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_DECRYPT, RSA_R_DATA_GREATER_THAN_MOD_LEN);
+        goto err;
+    }
+
+    if (BN_bin2bn(from, flen, f) == NULL)
+        goto err;
+
+    if (BN_ucmp(f, rsa->n) >= 0) {
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_DECRYPT,
+               RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
+        goto err;
+    }
+
+    if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
+        if (!BN_MONT_CTX_set_locked
+            (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
+            goto err;
+
+    if (!rsa->meth->bn_mod_exp(ret, f, rsa->e, rsa->n, ctx,
+                               rsa->_method_mod_n))
+        goto err;
+
+    if ((padding == RSA_X931_PADDING) && ((bn_get_words(ret)[0] & 0xf) != 12))
+        if (!BN_sub(ret, rsa->n, ret))
+            goto err;
+
+    p = buf;
+    i = BN_bn2bin(ret, p);
+
+    switch (padding) {
+    case RSA_PKCS1_PADDING:
+        r = RSA_padding_check_PKCS1_type_1(to, num, buf, i, num);
+        break;
+    case RSA_X931_PADDING:
+        r = RSA_padding_check_X931(to, num, buf, i, num);
+        break;
+    case RSA_NO_PADDING:
+        r = RSA_padding_check_none(to, num, buf, i, num);
+        break;
+    default:
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_DECRYPT, RSA_R_UNKNOWN_PADDING_TYPE);
+        goto err;
+    }
+    if (r < 0)
+        RSAerr(RSA_F_RSA_OSSL_PUBLIC_DECRYPT, RSA_R_PADDING_CHECK_FAILED);
+
+ err:
+    if (ctx != NULL)
+        BN_CTX_end(ctx);
+    BN_CTX_free(ctx);
+    OPENSSL_clear_free(buf, num);
+    return (r);
+}
+
+static int rsa_ossl_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
+{
+    BIGNUM *r1, *m1, *vrfy;
+    BIGNUM *local_dmp1, *local_dmq1, *local_c, *local_r1;
+    BIGNUM *dmp1, *dmq1, *c, *pr1;
+    int ret = 0;
+
+    BN_CTX_start(ctx);
+
+    local_dmp1 = BN_new();
+    local_dmq1 = BN_new();
+    local_c = BN_new();
+    local_r1 = BN_new();
+    if (local_dmp1 == NULL
+            || local_dmq1 == NULL || local_c == NULL || local_r1 == NULL)
+        goto err;
+
+    r1 = BN_CTX_get(ctx);
+    m1 = BN_CTX_get(ctx);
+    vrfy = BN_CTX_get(ctx);
+
+    {
+        BIGNUM *local_p = NULL, *local_q = NULL;
+        BIGNUM *p = NULL, *q = NULL;
+
+        /*
+         * Make sure BN_mod_inverse in Montgomery intialization uses the
+         * BN_FLG_CONSTTIME flag (unless RSA_FLAG_NO_CONSTTIME is set)
+         */
+        if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+            local_p = p = BN_new();
+            if (p == NULL)
+                goto err;
+            BN_with_flags(p, rsa->p, BN_FLG_CONSTTIME);
+
+            local_q = q = BN_new();
+            if (q == NULL) {
+                BN_free(local_p);
+                goto err;
+            }
+            BN_with_flags(q, rsa->q, BN_FLG_CONSTTIME);
+        } else {
+            p = rsa->p;
+            q = rsa->q;
+        }
+
+        if (rsa->flags & RSA_FLAG_CACHE_PRIVATE) {
+            if (!BN_MONT_CTX_set_locked
+                (&rsa->_method_mod_p, CRYPTO_LOCK_RSA, p, ctx)
+                || !BN_MONT_CTX_set_locked(&rsa->_method_mod_q,
+                                           CRYPTO_LOCK_RSA, q, ctx)) {
+                BN_free(local_p);
+                BN_free(local_q);
+                goto err;
+            }
+        }
+        BN_free(local_p);
+        BN_free(local_q);
+    }
+
+    if (rsa->flags & RSA_FLAG_CACHE_PUBLIC)
+        if (!BN_MONT_CTX_set_locked
+            (&rsa->_method_mod_n, CRYPTO_LOCK_RSA, rsa->n, ctx))
+            goto err;
+
+    /* compute I mod q */
+    if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+        c = local_c;
+        BN_with_flags(c, I, BN_FLG_CONSTTIME);
+        if (!BN_mod(r1, c, rsa->q, ctx))
+            goto err;
+    } else {
+        if (!BN_mod(r1, I, rsa->q, ctx))
+            goto err;
+    }
+
+    /* compute r1^dmq1 mod q */
+    if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+        dmq1 = local_dmq1;
+        BN_with_flags(dmq1, rsa->dmq1, BN_FLG_CONSTTIME);
+    } else
+        dmq1 = rsa->dmq1;
+    if (!rsa->meth->bn_mod_exp(m1, r1, dmq1, rsa->q, ctx, rsa->_method_mod_q))
+        goto err;
+
+    /* compute I mod p */
+    if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+        c = local_c;
+        BN_with_flags(c, I, BN_FLG_CONSTTIME);
+        if (!BN_mod(r1, c, rsa->p, ctx))
+            goto err;
+    } else {
+        if (!BN_mod(r1, I, rsa->p, ctx))
+            goto err;
+    }
+
+    /* compute r1^dmp1 mod p */
+    if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+        dmp1 = local_dmp1;
+        BN_with_flags(dmp1, rsa->dmp1, BN_FLG_CONSTTIME);
+    } else
+        dmp1 = rsa->dmp1;
+    if (!rsa->meth->bn_mod_exp(r0, r1, dmp1, rsa->p, ctx, rsa->_method_mod_p))
+        goto err;
+
+    if (!BN_sub(r0, r0, m1))
+        goto err;
+    /*
+     * This will help stop the size of r0 increasing, which does affect the
+     * multiply if it optimised for a power of 2 size
+     */
+    if (BN_is_negative(r0))
+        if (!BN_add(r0, r0, rsa->p))
+            goto err;
+
+    if (!BN_mul(r1, r0, rsa->iqmp, ctx))
+        goto err;
+
+    /* Turn BN_FLG_CONSTTIME flag on before division operation */
+    if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+        pr1 = local_r1;
+        BN_with_flags(pr1, r1, BN_FLG_CONSTTIME);
+    } else
+        pr1 = r1;
+    if (!BN_mod(r0, pr1, rsa->p, ctx))
+        goto err;
+
+    /*
+     * If p < q it is occasionally possible for the correction of adding 'p'
+     * if r0 is negative above to leave the result still negative. This can
+     * break the private key operations: the following second correction
+     * should *always* correct this rare occurrence. This will *never* happen
+     * with OpenSSL generated keys because they ensure p > q [steve]
+     */
+    if (BN_is_negative(r0))
+        if (!BN_add(r0, r0, rsa->p))
+            goto err;
+    if (!BN_mul(r1, r0, rsa->q, ctx))
+        goto err;
+    if (!BN_add(r0, r1, m1))
+        goto err;
+
+    if (rsa->e && rsa->n) {
+        if (!rsa->meth->bn_mod_exp(vrfy, r0, rsa->e, rsa->n, ctx,
+                                   rsa->_method_mod_n))
+            goto err;
+        /*
+         * If 'I' was greater than (or equal to) rsa->n, the operation will
+         * be equivalent to using 'I mod n'. However, the result of the
+         * verify will *always* be less than 'n' so we don't check for
+         * absolute equality, just congruency.
+         */
+        if (!BN_sub(vrfy, vrfy, I))
+            goto err;
+        if (!BN_mod(vrfy, vrfy, rsa->n, ctx))
+            goto err;
+        if (BN_is_negative(vrfy))
+            if (!BN_add(vrfy, vrfy, rsa->n))
+                goto err;
+        if (!BN_is_zero(vrfy)) {
+            /*
+             * 'I' and 'vrfy' aren't congruent mod n. Don't leak
+             * miscalculated CRT output, just do a raw (slower) mod_exp and
+             * return that instead.
+             */
+
+            BIGNUM *local_d = NULL;
+            BIGNUM *d = NULL;
+
+            if (!(rsa->flags & RSA_FLAG_NO_CONSTTIME)) {
+                local_d = d = BN_new();
+                if (d == NULL)
+                    goto err;
+                BN_with_flags(d, rsa->d, BN_FLG_CONSTTIME);
+            } else
+                d = rsa->d;
+            if (!rsa->meth->bn_mod_exp(r0, I, d, rsa->n, ctx,
+                                       rsa->_method_mod_n)) {
+                BN_free(local_d);
+                goto err;
+            }
+
+            BN_free(local_d);
+        }
+    }
+    ret = 1;
+ err:
+    BN_free(local_dmp1);
+    BN_free(local_dmq1);
+    BN_free(local_c);
+    BN_free(local_r1);
+    BN_CTX_end(ctx);
+    return (ret);
+}
+
+static int rsa_ossl_init(RSA *rsa)
+{
+    rsa->flags |= RSA_FLAG_CACHE_PUBLIC | RSA_FLAG_CACHE_PRIVATE;
+    return (1);
+}
+
+static int rsa_ossl_finish(RSA *rsa)
+{
+    BN_MONT_CTX_free(rsa->_method_mod_n);
+    BN_MONT_CTX_free(rsa->_method_mod_p);
+    BN_MONT_CTX_free(rsa->_method_mod_q);
+    return (1);
+}
+
+#endif