/*
- * Copyright 1995-2018 The OpenSSL Project Authors. All Rights Reserved.
+ * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.
*
- * Licensed under the OpenSSL license (the "License"). You may not use
+ * Licensed under the Apache License 2.0 (the "License"). You may not use
* this file except in compliance with the License. You can obtain a copy
* in the file LICENSE in the source distribution or at
* https://www.openssl.org/source/license.html
*/
#include "internal/cryptlib.h"
-#include "bn_lcl.h"
+#include "bn_local.h"
#define MONT_WORD /* use the faster word-based algorithm */
#ifdef MONT_WORD
-static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont);
+static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont);
#endif
int BN_mod_mul_montgomery(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
BN_MONT_CTX *mont, BN_CTX *ctx)
+{
+ int ret = bn_mul_mont_fixed_top(r, a, b, mont, ctx);
+
+ bn_correct_top(r);
+ bn_check_top(r);
+
+ return ret;
+}
+
+int bn_mul_mont_fixed_top(BIGNUM *r, const BIGNUM *a, const BIGNUM *b,
+ BN_MONT_CTX *mont, BN_CTX *ctx)
{
BIGNUM *tmp;
int ret = 0;
if (bn_mul_mont(r->d, a->d, b->d, mont->N.d, mont->n0, num)) {
r->neg = a->neg ^ b->neg;
r->top = num;
- bn_correct_top(r);
+ r->flags |= BN_FLG_FIXED_TOP;
return 1;
}
}
bn_check_top(tmp);
if (a == b) {
- if (!BN_sqr(tmp, a, ctx))
+ if (!bn_sqr_fixed_top(tmp, a, ctx))
goto err;
} else {
- if (!BN_mul(tmp, a, b, ctx))
+ if (!bn_mul_fixed_top(tmp, a, b, ctx))
goto err;
}
/* reduce from aRR to aR */
#ifdef MONT_WORD
- if (!BN_from_montgomery_word(r, tmp, mont))
+ if (!bn_from_montgomery_word(r, tmp, mont))
goto err;
#else
if (!BN_from_montgomery(r, tmp, mont, ctx))
goto err;
#endif
- bn_check_top(r);
ret = 1;
err:
BN_CTX_end(ctx);
}
#ifdef MONT_WORD
-static int BN_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
+static int bn_from_montgomery_word(BIGNUM *ret, BIGNUM *r, BN_MONT_CTX *mont)
{
BIGNUM *n;
BN_ULONG *ap, *np, *rp, n0, v, carry;
int nl, max, i;
+ unsigned int rtop;
n = &(mont->N);
nl = n->top;
rp = r->d;
/* clear the top words of T */
- i = max - r->top;
- if (i)
- memset(&rp[r->top], 0, sizeof(*rp) * i);
+ for (rtop = r->top, i = 0; i < max; i++) {
+ v = (BN_ULONG)0 - ((i - rtop) >> (8 * sizeof(rtop) - 1));
+ rp[i] &= v;
+ }
r->top = max;
+ r->flags |= BN_FLG_FIXED_TOP;
n0 = mont->n0[0];
/*
if (bn_wexpand(ret, nl) == NULL)
return 0;
ret->top = nl;
+ ret->flags |= BN_FLG_FIXED_TOP;
ret->neg = r->neg;
rp = ret->d;
rp[i] = (carry & ap[i]) | (~carry & rp[i]);
ap[i] = 0;
}
- bn_correct_top(r);
- bn_correct_top(ret);
- bn_check_top(ret);
return 1;
}
int BN_from_montgomery(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
BN_CTX *ctx)
+{
+ int retn;
+
+ retn = bn_from_mont_fixed_top(ret, a, mont, ctx);
+ bn_correct_top(ret);
+ bn_check_top(ret);
+
+ return retn;
+}
+
+int bn_from_mont_fixed_top(BIGNUM *ret, const BIGNUM *a, BN_MONT_CTX *mont,
+ BN_CTX *ctx)
{
int retn = 0;
#ifdef MONT_WORD
BIGNUM *t;
BN_CTX_start(ctx);
- if ((t = BN_CTX_get(ctx)) && BN_copy(t, a))
- retn = BN_from_montgomery_word(ret, t, mont);
+ if ((t = BN_CTX_get(ctx)) && BN_copy(t, a)) {
+ retn = bn_from_montgomery_word(ret, t, mont);
+ }
BN_CTX_end(ctx);
#else /* !MONT_WORD */
BIGNUM *t1, *t2;
return retn;
}
+int bn_to_mont_fixed_top(BIGNUM *r, const BIGNUM *a, BN_MONT_CTX *mont,
+ BN_CTX *ctx)
+{
+ return bn_mul_mont_fixed_top(r, a, &(mont->RR), mont, ctx);
+}
+
BN_MONT_CTX *BN_MONT_CTX_new(void)
{
BN_MONT_CTX *ret;
if ((ret = OPENSSL_malloc(sizeof(*ret))) == NULL) {
- BNerr(BN_F_BN_MONT_CTX_NEW, ERR_R_MALLOC_FAILURE);
+ ERR_raise(ERR_LIB_BN, ERR_R_MALLOC_FAILURE);
return NULL;
}
int BN_MONT_CTX_set(BN_MONT_CTX *mont, const BIGNUM *mod, BN_CTX *ctx)
{
- int ret = 0;
+ int i, ret = 0;
BIGNUM *Ri, *R;
if (BN_is_zero(mod))
if (!BN_mod(&(mont->RR), &(mont->RR), &(mont->N), ctx))
goto err;
+ for (i = mont->RR.top, ret = mont->N.top; i < ret; i++)
+ mont->RR.d[i] = 0;
+ mont->RR.top = ret;
+ mont->RR.flags |= BN_FLG_FIXED_TOP;
+
ret = 1;
err:
BN_CTX_end(ctx);
{
BN_MONT_CTX *ret;
- CRYPTO_THREAD_read_lock(lock);
+ if (!CRYPTO_THREAD_read_lock(lock))
+ return NULL;
ret = *pmont;
CRYPTO_THREAD_unlock(lock);
if (ret)
return ret;
/*
- * We don't want to serialise globally while doing our lazy-init math in
+ * We don't want to serialize globally while doing our lazy-init math in
* BN_MONT_CTX_set. That punishes threads that are doing independent
* things. Instead, punish the case where more than one thread tries to
* lazy-init the same 'pmont', by having each do the lazy-init math work
}
/* The locked compare-and-set, after the local work is done. */
- CRYPTO_THREAD_write_lock(lock);
+ if (!CRYPTO_THREAD_write_lock(lock)) {
+ BN_MONT_CTX_free(ret);
+ return NULL;
+ }
+
if (*pmont) {
BN_MONT_CTX_free(ret);
ret = *pmont;