Minimise the amount of code dependent on BN_DEBUG_RAND. In particular,

redefine bn_clear_top2max() to be a NOP in the non-debugging case, and
remove some unnecessary usages in bn_nist.c.

Submitted by: Nils Larsch
Reviewed by: Geoff Thorpe, Ulf Möller

diff --git a/crypto/bn/bn_div.c b/crypto/bn/bn_div.c
index 2f464b31d1131b5493807a0c23a361587b6b0606..556fcda1e3686d88745550a8099b501ed81be154 100644 (file)
--- a/crypto/bn/bn_div.c
+++ b/crypto/bn/bn_div.c
@@ -232,10 +232,8 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
        wnum.neg   = 0;
        wnum.d     = &(snum->d[loop]);
        wnum.top   = div_n;
-#ifdef BN_DEBUG_RAND
        /* only needed when BN_ucmp messes up the values between top and max */
        wnum.dmax  = snum->dmax - loop; /* so we don't step out of bounds */
-#endif
 
        /* Get the top 2 words of sdiv */
        /* div_n=sdiv->top; */
@@ -256,12 +254,10 @@ int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
 
        if (BN_ucmp(&wnum,sdiv) >= 0)
                {
-#ifdef BN_DEBUG_RAND
                /* If BN_DEBUG_RAND is defined BN_ucmp changes (via
                 * bn_pollute) the const bignum arguments =>
                 * clean the values between top and max again */
                bn_clear_top2max(&wnum);
-#endif
                bn_sub_words(wnum.d, wnum.d, sdiv->d, div_n);
                *resp=1;
                }
@@ -384,13 +380,13 @@ X) -> 0x%08X\n",
                /* store part of the result */
                *resp = q;
                }
+       bn_correct_top(snum);
        if (rm != NULL)
                {
                /* Keep a copy of the neg flag in num because if rm==num
                 * BN_rshift() will overwrite it.
                 */
                int neg = num->neg;
-               bn_correct_top(snum);
                BN_rshift(rm,snum,norm_shift);
                if (!BN_is_zero(rm))
                        rm->neg = neg;

diff --git a/crypto/bn/bn_lcl.h b/crypto/bn/bn_lcl.h
index 18960f191ba5d11ac68666d3ea2c53305756e8d8..45e19221aafe2280bcb57432ca8d87ad077b8b4a 100644 (file)
--- a/crypto/bn/bn_lcl.h
+++ b/crypto/bn/bn_lcl.h
@@ -240,7 +240,7 @@ extern "C" {
 #define Lw(t)    (((BN_ULONG)(t))&BN_MASK2)
 #define Hw(t)    (((BN_ULONG)((t)>>BN_BITS2))&BN_MASK2)
 
-
+#ifdef BN_DEBUG_RAND
 #define bn_clear_top2max(a) \
        { \
        int      ind = (a)->dmax - (a)->top; \
@@ -248,6 +248,9 @@ extern "C" {
        for (; ind != 0; ind--) \
                *(++ftl) = 0x0; \
        }
+#else
+#define bn_clear_top2max(a)
+#endif
 
 #ifdef BN_LLONG
 #define mul_add(r,a,w,c) { \

diff --git a/crypto/bn/bn_nist.c b/crypto/bn/bn_nist.c
index f30f6c65d1692acb9cb643652ca489544c1b7876..a29503be25e9ae47c3a167a2c6e77acd7193a4e7 100644 (file)
--- a/crypto/bn/bn_nist.c
+++ b/crypto/bn/bn_nist.c
@@ -359,12 +359,7 @@ int BN_nist_mod_192(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
                        --carry; 
                }
        r->top = BN_NIST_192_TOP;
-
-#if 1
-       bn_clear_top2max(r);
-#endif
        bn_correct_top(r);
-
        if (BN_ucmp(r, field) >= 0)
                {
                bn_sub_words(r_d, r_d, _nist_p_192, BN_NIST_192_TOP);
@@ -453,11 +448,7 @@ int BN_nist_mod_224(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
                        }
 
        r->top = BN_NIST_224_TOP;
-#if 1
-       bn_clear_top2max(r);
-#endif
        bn_correct_top(r);
-
        if (BN_ucmp(r, field) >= 0)
                {
                bn_sub_words(r_d, r_d, _nist_p_224, BN_NIST_224_TOP);
@@ -612,11 +603,7 @@ int BN_nist_mod_256(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
                }
 
        r->top = BN_NIST_256_TOP;
-#if 1
-       bn_clear_top2max(r);
-#endif
        bn_correct_top(r);
-
        if (BN_ucmp(r, field) >= 0)
                {
                bn_sub_words(r_d, r_d, _nist_p_256, BN_NIST_256_TOP);
@@ -781,11 +768,7 @@ int BN_nist_mod_384(BIGNUM *r, const BIGNUM *a, const BIGNUM *field,
                }
 
        r->top = BN_NIST_384_TOP;
-#if 1
-       bn_clear_top2max(r);
-#endif
        bn_correct_top(r);
-
        if (BN_ucmp(r, field) >= 0)
                {
                bn_sub_words(r_d, r_d, _nist_p_384, BN_NIST_384_TOP);