Implement fixed-window exponentiation to mitigate hyper-threading
[openssl.git] / crypto / rsa / rsa_eay.c
index 21755c0e2fc5959461321b1414eb4ef143026a5d..175ab8a789d8afd846a0cf5f3422073569a412fb 100644 (file)
  * copied and put under another distribution licence
  * [including the GNU Public Licence.]
  */
+/* ====================================================================
+ * Copyright (c) 1998-2005 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 <stdio.h>
 #include "cryptlib.h"
@@ -320,11 +373,25 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
                (rsa->dmp1 != NULL) &&
                (rsa->dmq1 != NULL) &&
                (rsa->iqmp != NULL)) )
-               { if (!rsa->meth->rsa_mod_exp(ret,f,rsa,ctx)) goto err; }
+               { 
+               if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
+               }
        else
                {
+               BIGNUM local_d;
+               BIGNUM *d = NULL;
+               
+               if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+                       {
+                       d = &local_d;
+                       BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
+                       }
+               else
+                       d = rsa->d;
+
                MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
-               if (!rsa->meth->bn_mod_exp(ret,f,rsa->d,rsa->n,ctx,
+
+               if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
                                rsa->_method_mod_n)) goto err;
                }
 
@@ -416,13 +483,26 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
                (rsa->dmp1 != NULL) &&
                (rsa->dmq1 != NULL) &&
                (rsa->iqmp != NULL)) )
-               { if (!rsa->meth->rsa_mod_exp(ret,f,rsa,ctx)) goto err; }
+               {
+               if (!rsa->meth->rsa_mod_exp(ret, f, rsa, ctx)) goto err;
+               }
        else
                {
+               BIGNUM local_d;
+               BIGNUM *d = NULL;
+               
+               if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+                       {
+                       d = &local_d;
+                       BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
+                       }
+               else
+                       d = rsa->d;
+
                MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
-               if (!rsa->meth->bn_mod_exp(ret,f,rsa->d,rsa->n,ctx,
+               if (!rsa->meth->bn_mod_exp(ret,f,d,rsa->n,ctx,
                                rsa->_method_mod_n))
-                       goto err;
+                 goto err;
                }
 
        if (blinding)
@@ -547,6 +627,8 @@ err:
 static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
        {
        BIGNUM *r1,*m1,*vrfy;
+       BIGNUM local_dmp1, local_dmq1;
+       BIGNUM *dmp1, *dmq1;
        int ret=0;
 
        BN_CTX_start(ctx);
@@ -559,11 +641,25 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
        MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
 
        if (!BN_mod(r1,I,rsa->q,ctx)) goto err;
-       if (!rsa->meth->bn_mod_exp(m1,r1,rsa->dmq1,rsa->q,ctx,
+       if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+               {
+               dmq1 = &local_dmq1;
+               BN_with_flags(dmq1, rsa->dmq1, BN_FLG_EXP_CONSTTIME);
+               }
+       else
+               dmq1 = rsa->dmq1;
+       if (!rsa->meth->bn_mod_exp(m1,r1,dmq1,rsa->q,ctx,
                rsa->_method_mod_q)) goto err;
 
        if (!BN_mod(r1,I,rsa->p,ctx)) goto err;
-       if (!rsa->meth->bn_mod_exp(r0,r1,rsa->dmp1,rsa->p,ctx,
+       if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+               {
+               dmp1 = &local_dmp1;
+               BN_with_flags(dmp1, rsa->dmp1, BN_FLG_EXP_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;
@@ -598,11 +694,24 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
                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. */
-                       if (!rsa->meth->bn_mod_exp(r0,I,rsa->d,rsa->n,ctx,
-                                       rsa->_method_mod_n)) goto err;
+
+                       BIGNUM local_d;
+                       BIGNUM *d = NULL;
+               
+                       if (!(rsa->flags & RSA_FLAG_NO_EXP_CONSTTIME))
+                               {
+                               d = &local_d;
+                               BN_with_flags(d, rsa->d, BN_FLG_EXP_CONSTTIME);
+                               }
+                       else
+                               d = rsa->d;
+                       if (!rsa->meth->bn_mod_exp(r0,I,d,rsa->n,ctx,
+                                                  rsa->_method_mod_n)) goto err;
+                       }
                }
        ret=1;
 err: