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By adding a BN_CTX parameter to the 'rsa_mod_exp' callback, private key

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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.
This commit is contained in:
Geoff Thorpe
2004-03-25 02:52:04 +00:00
parent 2d2a5ba32a
commit 46ef873f0b
9 changed files with 112 additions and 125 deletions
Download Patch File Download Diff File Expand all files Collapse all files

181
crypto/rsa/rsa_eay.c
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@@ -72,7 +72,7 @@ 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);
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={
@@ -137,16 +137,18 @@ static int rsa_eay_mont_helper(BN_MONT_CTX **ptr, const BIGNUM *modulus, BN_CTX
static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa, int padding)
{
BIGNUM f,ret;
BIGNUM *f,*ret;
int i,j,k,num=0,r= -1;
unsigned char *buf=NULL;
BN_CTX *ctx=NULL;
BN_init(&f);
BN_init(&ret);
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);
if ((buf=(unsigned char *)OPENSSL_malloc(num)) == NULL)
buf = OPENSSL_malloc(num);
if (!f || !ret || !buf)
{
RSAerr(RSA_F_RSA_EAY_PUBLIC_ENCRYPT,ERR_R_MALLOC_FAILURE);
goto err;
@@ -174,9 +176,9 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
}
if (i <= 0) goto err;
if (BN_bin2bn(buf,num,&f) == NULL) goto err;
if (BN_bin2bn(buf,num,f) == NULL) goto err;
if (BN_ucmp(&f, rsa->n) >= 0)
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);
@@ -185,21 +187,23 @@ static int RSA_eay_public_encrypt(int flen, const unsigned char *from,
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,
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]));
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_free(ctx);
BN_clear_free(&f);
BN_clear_free(&ret);
if (ctx != NULL)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (buf != NULL)
{
OPENSSL_cleanse(buf,num);
@@ -265,19 +269,20 @@ err:
static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa, int padding)
{
BIGNUM f,ret;
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;
BN_init(&f);
BN_init(&ret);
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);
if ((buf=(unsigned char *)OPENSSL_malloc(num)) == NULL)
buf = OPENSSL_malloc(num);
if(!f || !ret || !buf)
{
RSAerr(RSA_F_RSA_EAY_PRIVATE_ENCRYPT,ERR_R_MALLOC_FAILURE);
goto err;
@@ -298,9 +303,9 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
}
if (i <= 0) goto err;
if (BN_bin2bn(buf,num,&f) == NULL) goto err;
if (BN_bin2bn(buf,num,f) == NULL) goto err;
if (BN_ucmp(&f, rsa->n) >= 0)
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);
@@ -339,7 +344,7 @@ static int RSA_eay_private_encrypt(int flen, const unsigned char *from,
}
if (blinding)
if (!BN_BLINDING_convert(&f, blinding, ctx)) goto err;
if (!BN_BLINDING_convert(f, blinding, ctx)) goto err;
if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
((rsa->p != NULL) &&
@@ -347,29 +352,31 @@ 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)) goto err; }
{ 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,
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;
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]));
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_free(ctx);
BN_clear_free(&ret);
BN_clear_free(&f);
if (ctx != NULL)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (local_blinding)
BN_BLINDING_free(blinding);
if (buf != NULL)
@@ -383,7 +390,7 @@ err:
static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa, int padding)
{
BIGNUM f,ret;
BIGNUM *f,*ret;
int j,num=0,r= -1;
unsigned char *p;
unsigned char *buf=NULL;
@@ -391,14 +398,13 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
int local_blinding = 0;
BN_BLINDING *blinding = NULL;
BN_init(&f);
BN_init(&ret);
ctx=BN_CTX_new();
if (ctx == NULL) goto err;
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);
if ((buf=(unsigned char *)OPENSSL_malloc(num)) == NULL)
buf = OPENSSL_malloc(num);
if(!f || !ret || !buf)
{
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,ERR_R_MALLOC_FAILURE);
goto err;
@@ -413,9 +419,9 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
}
/* make data into a big number */
if (BN_bin2bn(from,(int)flen,&f) == NULL) goto err;
if (BN_bin2bn(from,(int)flen,f) == NULL) goto err;
if (BN_ucmp(&f, rsa->n) >= 0)
if (BN_ucmp(f, rsa->n) >= 0)
{
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
goto err;
@@ -453,7 +459,7 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
}
if (blinding)
if (!BN_BLINDING_convert(&f, blinding, ctx)) goto err;
if (!BN_BLINDING_convert(f, blinding, ctx)) goto err;
/* do the decrypt */
if ( (rsa->flags & RSA_FLAG_EXT_PKEY) ||
@@ -462,20 +468,20 @@ 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)) goto err; }
{ 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,
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;
if (!BN_BLINDING_invert(ret, blinding, ctx)) goto err;
p=buf;
j=BN_bn2bin(&ret,p); /* j is only used with no-padding mode */
j=BN_bn2bin(ret,p); /* j is only used with no-padding mode */
switch (padding)
{
@@ -501,9 +507,11 @@ static int RSA_eay_private_decrypt(int flen, const unsigned char *from,
RSAerr(RSA_F_RSA_EAY_PRIVATE_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
err:
if (ctx != NULL) BN_CTX_free(ctx);
BN_clear_free(&f);
BN_clear_free(&ret);
if (ctx != NULL)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (local_blinding)
BN_BLINDING_free(blinding);
if (buf != NULL)
@@ -518,20 +526,19 @@ err:
static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa, int padding)
{
BIGNUM f,ret;
BIGNUM *f,*ret;
int i,num=0,r= -1;
unsigned char *p;
unsigned char *buf=NULL;
BN_CTX *ctx=NULL;
BN_init(&f);
BN_init(&ret);
ctx=BN_CTX_new();
if (ctx == NULL) goto err;
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=(unsigned char *)OPENSSL_malloc(num);
if (buf == NULL)
buf = OPENSSL_malloc(num);
if(!f || !ret || !buf)
{
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,ERR_R_MALLOC_FAILURE);
goto err;
@@ -545,9 +552,9 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
goto err;
}
if (BN_bin2bn(from,flen,&f) == NULL) goto err;
if (BN_bin2bn(from,flen,f) == NULL) goto err;
if (BN_ucmp(&f, rsa->n) >= 0)
if (BN_ucmp(f, rsa->n) >= 0)
{
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_DATA_TOO_LARGE_FOR_MODULUS);
goto err;
@@ -555,11 +562,11 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
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,
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);
i=BN_bn2bin(ret,p);
switch (padding)
{
@@ -577,9 +584,11 @@ static int RSA_eay_public_decrypt(int flen, const unsigned char *from,
RSAerr(RSA_F_RSA_EAY_PUBLIC_DECRYPT,RSA_R_PADDING_CHECK_FAILED);
err:
if (ctx != NULL) BN_CTX_free(ctx);
BN_clear_free(&f);
BN_clear_free(&ret);
if (ctx != NULL)
{
BN_CTX_end(ctx);
BN_CTX_free(ctx);
}
if (buf != NULL)
{
OPENSSL_cleanse(buf,num);
@@ -588,37 +597,36 @@ err:
return(r);
}
static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa, BN_CTX *ctx)
{
BIGNUM r1,m1,vrfy;
BIGNUM *r1,*m1,*vrfy;
int ret=0;
BN_CTX *ctx;
BN_init(&m1);
BN_init(&r1);
BN_init(&vrfy);
if ((ctx=BN_CTX_new()) == NULL) goto err;
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,
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,
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;
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 (!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
@@ -628,21 +636,21 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
*/
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 (!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 (!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))
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. */
@@ -651,10 +659,7 @@ static int RSA_eay_mod_exp(BIGNUM *r0, const BIGNUM *I, RSA *rsa)
}
ret=1;
err:
BN_clear_free(&m1);
BN_clear_free(&r1);
BN_clear_free(&vrfy);
BN_CTX_free(ctx);
BN_CTX_end(ctx);
return(ret);
}