openssl/crypto/rsa/rsa_eay.c
Geoff Thorpe 46ef873f0b By adding a BN_CTX parameter to the 'rsa_mod_exp' callback, private key
operations no longer require two distinct BN_CTX structures. This may put
more "strain" on the current BN_CTX implementation (which has a fixed limit
to the number of variables it will hold), but so far this limit is not
triggered by any of the tests pass and I will be changing BN_CTX in the
near future to avoid this problem anyway.

This also changes the default RSA implementation code to use the BN_CTX in
favour of initialising some of its variables locally in each function.
2004-03-25 02:52:04 +00:00

684 lines
19 KiB
C

/* crypto/rsa/rsa_eay.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.]
*/
#include <stdio.h>
#include "cryptlib.h"
#include <openssl/bn.h>
#include <openssl/rsa.h>
#include <openssl/rand.h>
#ifndef RSA_NULL
static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa,int padding);
static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa,int padding);
static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa,int padding);
static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa,int padding);
static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *i, RSA *rsa, BN_CTX *ctx);
static int RSA_eay_init(RSA *rsa);
static int RSA_eay_finish(RSA *rsa);
static RSA_METHOD rsa_pkcs1_eay_meth={
"Eric Young's PKCS#1 RSA",
RSA_eay_public_encrypt,
RSA_eay_public_decrypt, /* signature verification */
RSA_eay_private_encrypt, /* signing */
RSA_eay_private_decrypt,
RSA_eay_mod_exp,
BN_mod_exp_mont, /* XXX probably we should not use Montgomery if e == 3 */
RSA_eay_init,
RSA_eay_finish,
0, /* flags */
NULL,
0, /* rsa_sign */
0, /* rsa_verify */
NULL /* rsa_keygen */
};
const RSA_METHOD *RSA_PKCS1_SSLeay(void)
{
return(&rsa_pkcs1_eay_meth);
}
/* Static helper to reduce oodles of code duplication. As a slight
* optimisation, the "MONT_HELPER() macro must be used as front-end to this
* function, to prevent unnecessary function calls - there is an initial test
* that is performed by the macro-generated code. */
static int rsa_eay_mont_helper(BN_MONT_CTX **ptr, const BIGNUM *modulus, BN_CTX *ctx)
{
BN_MONT_CTX *bn_mont_ctx;
if((bn_mont_ctx = BN_MONT_CTX_new()) == NULL)
return 0;
if(!BN_MONT_CTX_set(bn_mont_ctx, modulus, ctx))
{
BN_MONT_CTX_free(bn_mont_ctx);
return 0;
}
if (*ptr == NULL) /* other thread may have finished first */
{
CRYPTO_w_lock(CRYPTO_LOCK_RSA);
if (*ptr == NULL) /* check again in the lock to stop races */
{
*ptr = bn_mont_ctx;
bn_mont_ctx = NULL;
}
CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
}
if (bn_mont_ctx)
BN_MONT_CTX_free(bn_mont_ctx);
return 1;
}
/* Usage example;
* MONT_HELPER(rsa, bn_ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
*/
#define MONT_HELPER(rsa, ctx, m, pre_cond, err_instr) \
if((pre_cond) && ((rsa)->_method_mod_##m == NULL) && \
!rsa_eay_mont_helper(&((rsa)->_method_mod_##m), \
(rsa)->m, (ctx))) \
err_instr
static int RSA_eay_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 ((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 || !ret || !buf)
{
RSAerr(RSA_F_RSA_EAY_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;
#ifndef OPENSSL_NO_SHA
case RSA_PKCS1_OAEP_PADDING:
i=RSA_padding_add_PKCS1_OAEP(buf,num,from,flen,NULL,0);
break;
#endif
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_EAY_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_EAY_PUBLIC_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
goto err;
}
MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, 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);
}
if (buf != NULL)
{
OPENSSL_cleanse(buf,num);
OPENSSL_free(buf);
}
return(r);
}
static int rsa_eay_blinding(RSA *rsa, BN_CTX *ctx)
{
int ret = 1;
CRYPTO_w_lock(CRYPTO_LOCK_RSA);
/* Check again inside the lock - the macro's check is racey */
if(rsa->blinding == NULL)
ret = RSA_blinding_on(rsa, ctx);
CRYPTO_w_unlock(CRYPTO_LOCK_RSA);
return ret;
}
#define BLINDING_HELPER(rsa, ctx, err_instr) \
do { \
if((!((rsa)->flags & RSA_FLAG_NO_BLINDING)) && \
((rsa)->blinding == NULL) && \
!rsa_eay_blinding(rsa, ctx)) \
err_instr \
} while(0)
static BN_BLINDING *setup_blinding(RSA *rsa, BN_CTX *ctx)
{
BIGNUM *A, *Ai;
BN_BLINDING *ret = NULL;
/* added in OpenSSL 0.9.6j and 0.9.7b */
/* NB: similar code appears in RSA_blinding_on (rsa_lib.c);
* this should be placed in a new function of its own, but for reasons
* of binary compatibility can't */
BN_CTX_start(ctx);
A = BN_CTX_get(ctx);
if ((RAND_status() == 0) && rsa->d != NULL && rsa->d->d != NULL)
{
/* if PRNG is not properly seeded, resort to secret exponent as unpredictable seed */
RAND_add(rsa->d->d, rsa->d->dmax * sizeof rsa->d->d[0], 0.0);
if (!BN_pseudo_rand_range(A,rsa->n)) goto err;
}
else
{
if (!BN_rand_range(A,rsa->n)) goto err;
}
if ((Ai=BN_mod_inverse(NULL,A,rsa->n,ctx)) == NULL) goto err;
if (!rsa->meth->bn_mod_exp(A,A,rsa->e,rsa->n,ctx,rsa->_method_mod_n))
goto err;
ret = BN_BLINDING_new(A,Ai,rsa->n);
BN_free(Ai);
err:
BN_CTX_end(ctx);
return ret;
}
/* signing */
static int RSA_eay_private_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;
int local_blinding = 0;
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 || !ret || !buf)
{
RSAerr(RSA_F_RSA_EAY_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_NO_PADDING:
i=RSA_padding_add_none(buf,num,from,flen);
break;
case RSA_SSLV23_PADDING:
default:
RSAerr(RSA_F_RSA_EAY_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_EAY_PRIVATE_ENCRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
goto err;
}
BLINDING_HELPER(rsa, ctx, goto err;);
blinding = rsa->blinding;
/* Now unless blinding is disabled, 'blinding' is non-NULL.
* But the BN_BLINDING object may be owned by some other thread
* (we don't want to keep it constant and we don't want to use
* lots of locking to avoid race conditions, so only a single
* thread can use it; other threads have to use local blinding
* factors) */
if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
{
if (blinding == NULL)
{
RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT, ERR_R_INTERNAL_ERROR);
goto err;
}
}
if (blinding != NULL)
{
if (blinding->thread_id != CRYPTO_thread_id())
{
/* we need a local one-time blinding factor */
blinding = setup_blinding(rsa, ctx);
if (blinding == NULL)
goto err;
local_blinding = 1;
}
}
if (blinding)
if (!BN_BLINDING_convert(f, blinding, 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
{
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,
rsa->_method_mod_n)) goto err;
}
if (blinding)
if (!BN_BLINDING_invert(ret, blinding, ctx)) 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);
}
if (local_blinding)
BN_BLINDING_free(blinding);
if (buf != NULL)
{
OPENSSL_cleanse(buf,num);
OPENSSL_free(buf);
}
return(r);
}
static int RSA_eay_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;
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 || !ret || !buf)
{
RSAerr(RSA_F_RSA_EAY_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_EAY_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_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
goto err;
}
BLINDING_HELPER(rsa, ctx, goto err;);
blinding = rsa->blinding;
/* Now unless blinding is disabled, 'blinding' is non-NULL.
* But the BN_BLINDING object may be owned by some other thread
* (we don't want to keep it constant and we don't want to use
* lots of locking to avoid race conditions, so only a single
* thread can use it; other threads have to use local blinding
* factors) */
if (!(rsa->flags & RSA_FLAG_NO_BLINDING))
{
if (blinding == NULL)
{
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT, ERR_R_INTERNAL_ERROR);
goto err;
}
}
if (blinding != NULL)
{
if (blinding->thread_id != CRYPTO_thread_id())
{
/* we need a local one-time blinding factor */
blinding = setup_blinding(rsa, ctx);
if (blinding == NULL)
goto err;
local_blinding = 1;
}
}
if (blinding)
if (!BN_BLINDING_convert(f, blinding, 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
{
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,
rsa->_method_mod_n))
goto err;
}
if (blinding)
if (!BN_BLINDING_invert(ret, blinding, 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;
#ifndef OPENSSL_NO_SHA
case RSA_PKCS1_OAEP_PADDING:
r=RSA_padding_check_PKCS1_OAEP(to,num,buf,j,num,NULL,0);
break;
#endif
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_EAY_PRIVATE_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
goto err;
}
if (r < 0)
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
err:
if (ctx != NULL)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (local_blinding)
BN_BLINDING_free(blinding);
if (buf != NULL)
{
OPENSSL_cleanse(buf,num);
OPENSSL_free(buf);
}
return(r);
}
/* signature verification */
static int RSA_eay_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((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 || !ret || !buf)
{
RSAerr(RSA_F_RSA_EAY_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_EAY_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_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
goto err;
}
MONT_HELPER(rsa, ctx, n, rsa->flags & RSA_FLAG_CACHE_PUBLIC, goto err);
if (!rsa->meth->bn_mod_exp(ret,f,rsa->e,rsa->n,ctx,
rsa->_method_mod_n)) 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_NO_PADDING:
r=RSA_padding_check_none(to,num,buf,i,num);
break;
default:
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_UNKNOWN_PADDING_TYPE);
goto err;
}
if (r < 0)
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
err:
if (ctx != NULL)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (buf != NULL)
{
OPENSSL_cleanse(buf,num);
OPENSSL_free(buf);
}
return(r);
}
static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
{
BIGNUM *r1,*m1,*vrfy;
int ret=0;
BN_CTX_start(ctx);
r1 = BN_CTX_get(ctx);
m1 = BN_CTX_get(ctx);
vrfy = BN_CTX_get(ctx);
MONT_HELPER(rsa, ctx, p, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
MONT_HELPER(rsa, ctx, q, rsa->flags & RSA_FLAG_CACHE_PRIVATE, goto err);
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,
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,
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_get_sign(r0))
if (!BN_add(r0,r0,rsa->p)) goto err;
if (!BN_mul(r1,r0,rsa->iqmp,ctx)) goto err;
if (!BN_mod(r0,r1,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_get_sign(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_get_sign(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;
}
ret=1;
err:
BN_CTX_end(ctx);
return(ret);
}
static int RSA_eay_init(RSA *rsa)
{
rsa->flags|=RSA_FLAG_CACHE_PUBLIC|RSA_FLAG_CACHE_PRIVATE;
return(1);
}
static int RSA_eay_finish(RSA *rsa)
{
if (rsa->_method_mod_n != NULL)
BN_MONT_CTX_free(rsa->_method_mod_n);
if (rsa->_method_mod_p != NULL)
BN_MONT_CTX_free(rsa->_method_mod_p);
if (rsa->_method_mod_q != NULL)
BN_MONT_CTX_free(rsa->_method_mod_q);
return(1);
}
#endif