BN_div_recp fix. I've ran divtest for 10 mins and it didn't exhibit a

single fault:-) Needless to mention that bnbug.c posted couple of days
ago passes as well...

diff --git a/crypto/bn/bn_recp.c b/crypto/bn/bn_recp.c
index 20a6da4efd9186a8dcc03e28d03c86a9c7199817..a6d7900a3cc9710b2c4d53c3bd42e580846856c5 100644 (file)
--- a/crypto/bn/bn_recp.c
+++ b/crypto/bn/bn_recp.c
@@ -128,7 +128,7 @@ err:
 int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BN_RECP_CTX *recp,
             BN_CTX *ctx)
        {
-       int i,j,ret=0,ex;
+       int i,j,ret=0;
        BIGNUM *a,*b,*d,*r;
 
        BN_CTX_start(ctx);
@@ -158,40 +158,30 @@ int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BN_RECP_CTX *recp,
         *
         */
        i=BN_num_bits(m);
-       if (i%2) i--;
 
-       j=recp->num_bits*2;
-       if (j > i)
-               {
-               i=j;
-               ex=0;
-               }
-       else
-               {
-               ex=(i-j)/2;
-               }
-
-       j=i/2;
+       j=recp->num_bits<<1;
+       if (j>i) i=j;
+       j>>=1;
 
        if (i != recp->shift)
                recp->shift=BN_reciprocal(&(recp->Nr),&(recp->N),
                        i,ctx);
 
-       if (!BN_rshift(a,m,j-ex)) goto err;
+       if (!BN_rshift(a,m,j)) goto err;
        if (!BN_mul(b,a,&(recp->Nr),ctx)) goto err;
-       if (!BN_rshift(d,b,j+ex)) goto err;
+       if (!BN_rshift(d,b,i-j)) goto err;
        d->neg=0;
        if (!BN_mul(b,&(recp->N),d,ctx)) goto err;
        if (!BN_usub(r,m,b)) goto err;
        r->neg=0;
 
-       j=0;
 #if 1
+       j=0;
        while (BN_ucmp(r,&(recp->N)) >= 0)
                {
                if (j++ > 2)
                        {
-#if 1
+#if 0
                        /* work around some bug:
                           -1CC0E177F93042B29D309839F8019DB93404D7A395F1E162
                           5383BF622A20B17E1BAA999336988B82B93F5FB77B55B4B68