Circumvent bug in SC5 without patch #107357-01.

[openssl.git] / crypto / bn / bn_div.c

diff --git a/crypto/bn/bn_div.c b/crypto/bn/bn_div.c
index 2263bdc7da083a7ce998e1d405b6c2a187a6b8c3..defcf90c8223d282b36306aa3737dc3b22ca7460 100644 (file)
--- a/crypto/bn/bn_div.c
+++ b/crypto/bn/bn_div.c
@@ -57,21 +57,19 @@
  */
 
 #include <stdio.h>
+#include <openssl/bn.h>
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
 /* The old slow way */
 #if 0
-int BN_div(dv, rem, m, d,ctx)
-BIGNUM *dv;
-BIGNUM *rem;
-BIGNUM *m;
-BIGNUM *d;
-BN_CTX *ctx;
+int BN_div(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BIGNUM *d, BN_CTX *ctx)
        {
        int i,nm,nd;
        BIGNUM *D;
 
+       bn_check_top(m);
+       bn_check_top(d);
        if (BN_is_zero(d))
                {
                BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
@@ -86,9 +84,9 @@ BN_CTX *ctx;
                return(1);
                }
 
-       D=ctx->bn[ctx->tos];
-       if (dv == NULL) dv=ctx->bn[ctx->tos+1];
-       if (rem == NULL) rem=ctx->bn[ctx->tos+2];
+       D= &(ctx->bn[ctx->tos]);
+       if (dv == NULL) dv= &(ctx->bn[ctx->tos+1]);
+       if (rem == NULL) rem= &(ctx->bn[ctx->tos+2]);
 
        nd=BN_num_bits(d);
        nm=BN_num_bits(m);
@@ -98,6 +96,7 @@ BN_CTX *ctx;
        /* The next 2 are needed so we can do a dv->d[0]|=1 later
         * since BN_lshift1 will only work once there is a value :-) */
        BN_zero(dv);
+       bn_wexpand(dv,1);
        dv->top=1;
 
        if (!BN_lshift(D,D,nm-nd)) return(0);
@@ -107,7 +106,7 @@ BN_CTX *ctx;
                if (BN_ucmp(rem,D) >= 0)
                        {
                        dv->d[0]|=1;
-                       bn_qsub(rem,rem,D);
+                       if (!BN_usub(rem,rem,D)) return(0);
                        }
 /* CAN IMPROVE (and have now :=) */
                if (!BN_rshift1(D,D)) return(0);
@@ -119,12 +118,8 @@ BN_CTX *ctx;
 
 #else
 
-int BN_div(dv, rm, num, divisor,ctx)
-BIGNUM *dv;
-BIGNUM *rm;
-BIGNUM *num;
-BIGNUM *divisor;
-BN_CTX *ctx;
+int BN_div(BIGNUM *dv, BIGNUM *rm, const BIGNUM *num, const BIGNUM *divisor,
+          BN_CTX *ctx)
        {
        int norm_shift,i,j,loop;
        BIGNUM *tmp,wnum,*snum,*sdiv,*res;
@@ -132,6 +127,9 @@ BN_CTX *ctx;
        BN_ULONG d0,d1;
        int num_n,div_n;
 
+       bn_check_top(num);
+       bn_check_top(divisor);
+
        if (BN_is_zero(divisor))
                {
                BNerr(BN_F_BN_DIV,BN_R_DIV_BY_ZERO);
@@ -146,12 +144,12 @@ BN_CTX *ctx;
                return(1);
                }
 
-       tmp=ctx->bn[ctx->tos]; 
+       tmp= &(ctx->bn[ctx->tos]);
        tmp->neg=0;
-       snum=ctx->bn[ctx->tos+1];
-       sdiv=ctx->bn[ctx->tos+2];
+       snum= &(ctx->bn[ctx->tos+1]);
+       sdiv= &(ctx->bn[ctx->tos+2]);
        if (dv == NULL)
-               res=ctx->bn[ctx->tos+3];
+               res= &(ctx->bn[ctx->tos+3]);
        else    res=dv;
 
        /* First we normalise the numbers */
@@ -168,10 +166,10 @@ BN_CTX *ctx;
        /* Lets setup a 'window' into snum
         * This is the part that corresponds to the current
         * 'area' being divided */
+       BN_init(&wnum);
        wnum.d=  &(snum->d[loop]);
        wnum.top= div_n;
-       wnum.max= snum->max; /* a bit of a lie */
-       wnum.neg= 0;
+       wnum.max= snum->max+1; /* a bit of a lie */
 
        /* Get the top 2 words of sdiv */
        /* i=sdiv->top; */
@@ -183,8 +181,8 @@ BN_CTX *ctx;
 
        /* Setup to 'res' */
        res->neg= (num->neg^divisor->neg);
-       res->top=loop;
        if (!bn_wexpand(res,(loop+1))) goto err;
+       res->top=loop;
        resp= &(res->d[loop-1]);
 
        /* space for temp */
@@ -192,7 +190,7 @@ BN_CTX *ctx;
 
        if (BN_ucmp(&wnum,sdiv) >= 0)
                {
-               bn_qsub(&wnum,&wnum,sdiv);
+               if (!BN_usub(&wnum,&wnum,sdiv)) goto err;
                *resp=1;
                res->d[res->top-1]=1;
                }
@@ -211,17 +209,17 @@ BN_CTX *ctx;
                if (n0 == d0)
                        q=BN_MASK2;
                else
-                       q=bn_div64(n0,n1,d0);
+                       q=bn_div_words(n0,n1,d0);
                {
 #ifdef BN_LLONG
                BN_ULLONG t1,t2,rem;
                t1=((BN_ULLONG)n0<<BN_BITS2)|n1;
                for (;;)
                        {
-                       t2=(BN_ULLONG)d1*q;
                        rem=t1-(BN_ULLONG)q*d0;
-                       if ((rem>>BN_BITS2) ||
-                               (t2 <= ((BN_ULLONG)(rem<<BN_BITS2)+wnump[-2])))
+                       t2=(BN_ULLONG)d1*q;
+                        if ((rem>>BN_BITS2) ||
+                               (t2 <= ((rem<<BN_BITS2)|wnump[-2])))
                                break;
                        q--;
                        }
@@ -284,3 +282,35 @@ err:
        }
 
 #endif
+
+/* rem != m */
+int BN_mod(BIGNUM *rem, const BIGNUM *m, const BIGNUM *d, BN_CTX *ctx)
+       {
+#if 0 /* The old slow way */
+       int i,nm,nd;
+       BIGNUM *dv;
+
+       if (BN_ucmp(m,d) < 0)
+               return((BN_copy(rem,m) == NULL)?0:1);
+
+       dv= &(ctx->bn[ctx->tos]);
+
+       if (!BN_copy(rem,m)) return(0);
+
+       nm=BN_num_bits(rem);
+       nd=BN_num_bits(d);
+       if (!BN_lshift(dv,d,nm-nd)) return(0);
+       for (i=nm-nd; i>=0; i--)
+               {
+               if (BN_cmp(rem,dv) >= 0)
+                       {
+                       if (!BN_sub(rem,rem,dv)) return(0);
+                       }
+               if (!BN_rshift1(dv,dv)) return(0);
+               }
+       return(1);
+#else
+       return(BN_div(NULL,rem,m,d,ctx));
+#endif
+       }
+