1 files changed, 140 insertions, 38 deletions

diff --git a/src/lib/libcrypto/bn/bn_recp.c b/src/lib/libcrypto/bn/bn_recp.c
index 72cd69d3fc..c1b0e230ea 100644
--- a/src/lib/libcrypto/bn/bn_recp.c
+++ b/src/lib/libcrypto/bn/bn_recp.c
@@ -60,66 +60,168 @@
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
-int BN_mod_mul_reciprocal(r, x, y, m, i, nb, ctx)
-BIGNUM *r;
-BIGNUM *x;
-BIGNUM *y;
-BIGNUM *m;
-BIGNUM *i;
-int nb;
-BN_CTX *ctx;
+void BN_RECP_CTX_init(BN_RECP_CTX *recp)
         {
-        int ret=0,j;
-        BIGNUM *a,*b,*c,*d;
+        BN_init(&(recp->N));
+        BN_init(&(recp->Nr));
+        recp->num_bits=0;
+        recp->flags=0;
+        }
+
+BN_RECP_CTX *BN_RECP_CTX_new(void)
+        {
+        BN_RECP_CTX *ret;
+
+        if ((ret=(BN_RECP_CTX *)Malloc(sizeof(BN_RECP_CTX))) == NULL)
+                return(NULL);
+
+        BN_RECP_CTX_init(ret);
+        ret->flags=BN_FLG_MALLOCED;
+        return(ret);
+        }
+
+void BN_RECP_CTX_free(BN_RECP_CTX *recp)
+        {
+        if(recp == NULL)
+            return;
 
-        a=ctx->bn[ctx->tos++];
-        b=ctx->bn[ctx->tos++];
-        c=ctx->bn[ctx->tos++];
-        d=ctx->bn[ctx->tos++];
+        BN_free(&(recp->N));
+        BN_free(&(recp->Nr));
+        if (recp->flags & BN_FLG_MALLOCED)
+                Free(recp);
+        }
 
-        if (x == y)
-                { if (!BN_sqr(a,x,ctx)) goto err; }
+int BN_RECP_CTX_set(BN_RECP_CTX *recp, const BIGNUM *d, BN_CTX *ctx)
+        {
+        BN_copy(&(recp->N),d);
+        BN_zero(&(recp->Nr));
+        recp->num_bits=BN_num_bits(d);
+        recp->shift=0;
+        return(1);
+        }
+
+int BN_mod_mul_reciprocal(BIGNUM *r, BIGNUM *x, BIGNUM *y, BN_RECP_CTX *recp,
+             BN_CTX *ctx)
+        {
+        int ret=0;
+        BIGNUM *a;
+
+        a= &(ctx->bn[ctx->tos++]);
+        if (y != NULL)
+                {
+                if (x == y)
+                        { if (!BN_sqr(a,x,ctx)) goto err; }
+                else
+                        { if (!BN_mul(a,x,y,ctx)) goto err; }
+                }
         else
-                { if (!BN_mul(a,x,y)) goto err; }
-        if (!BN_rshift(d,a,nb)) goto err;
-        if (!BN_mul(b,d,i)) goto err;
-        if (!BN_rshift(c,b,nb)) goto err;
-        if (!BN_mul(b,m,c)) goto err;
-        if (!BN_sub(r,a,b)) goto err;
+                a=x; /* Just do the mod */
+
+        BN_div_recp(NULL,r,a,recp,ctx);
+        ret=1;
+err:
+        ctx->tos--;
+        return(ret);
+        }
+
+int BN_div_recp(BIGNUM *dv, BIGNUM *rem, BIGNUM *m, BN_RECP_CTX *recp,
+             BN_CTX *ctx)
+        {
+        int i,j,tos,ret=0,ex;
+        BIGNUM *a,*b,*d,*r;
+
+        tos=ctx->tos;
+        a= &(ctx->bn[ctx->tos++]);
+        b= &(ctx->bn[ctx->tos++]);
+        if (dv != NULL)
+                d=dv;
+        else
+                d= &(ctx->bn[ctx->tos++]);
+        if (rem != NULL)
+                r=rem;
+        else
+                r= &(ctx->bn[ctx->tos++]);
+
+        if (BN_ucmp(m,&(recp->N)) < 0)
+                {
+                BN_zero(d);
+                BN_copy(r,m);
+                ctx->tos=tos;
+                return(1);
+                }
+
+        /* We want the remainder
+         * Given input of ABCDEF / ab
+         * we need multiply ABCDEF by 3 digests of the reciprocal of ab
+         *
+         */
+        i=BN_num_bits(m);
+
+        j=recp->num_bits*2;
+        if (j > i)
+                {
+                i=j;
+                ex=0;
+                }
+        else
+                {
+                ex=(i-j)/2;
+                }
+
+        j=i/2;
+
+        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_mul(b,a,&(recp->Nr),ctx)) goto err;
+        if (!BN_rshift(d,b,j+ex)) 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;
-        while (BN_cmp(r,m) >= 0)
+#if 1
+        while (BN_ucmp(r,&(recp->N)) >= 0)
                 {
                 if (j++ > 2)
                         {
                         BNerr(BN_F_BN_MOD_MUL_RECIPROCAL,BN_R_BAD_RECIPROCAL);
                         goto err;
                         }
-                if (!BN_sub(r,r,m)) goto err;
+                if (!BN_usub(r,r,&(recp->N))) goto err;
+                if (!BN_add_word(d,1)) goto err;
                 }
+#endif
 
+        r->neg=BN_is_zero(r)?0:m->neg;
+        d->neg=m->neg^recp->N.neg;
         ret=1;
 err:
-        ctx->tos-=4;
+        ctx->tos=tos;
         return(ret);
-        }
+        } 
 
-int BN_reciprocal(r, m,ctx)
-BIGNUM *r;
-BIGNUM *m;
-BN_CTX *ctx;
+/* len is the expected size of the result
+ * We actually calculate with an extra word of precision, so
+ * we can do faster division if the remainder is not required.
+ */
+int BN_reciprocal(BIGNUM *r, BIGNUM *m, int len, BN_CTX *ctx)
         {
-        int nm,ret= -1;
-        BIGNUM *t;
+        int ret= -1;
+        BIGNUM t;
 
-        t=ctx->bn[ctx->tos++];
+        BN_init(&t);
 
-        nm=BN_num_bits(m);
-        if (!BN_lshift(t,BN_value_one(),nm*2)) goto err;
+        BN_zero(&t);
+        if (!BN_set_bit(&t,len)) goto err;
 
-        if (!BN_div(r,NULL,t,m,ctx)) goto err;
-        ret=nm;
+        if (!BN_div(r,NULL,&t,m,ctx)) goto err;
+        ret=len;
 err:
-        ctx->tos--;
+        BN_free(&t);
         return(ret);
         }