1 files changed, 190 insertions, 24 deletions

diff --git a/src/lib/libcrypto/bn/bn_sqr.c b/src/lib/libcrypto/bn/bn_sqr.c
index a8464610e5..c1d0cca438 100644
--- a/src/lib/libcrypto/bn/bn_sqr.c
+++ b/src/lib/libcrypto/bn/bn_sqr.c
@@ -62,35 +62,105 @@
 
 /* r must not be a */
 /* I've just gone over this and it is now %20 faster on x86 - eay - 27 Jun 96 */
-int BN_sqr(r, a, ctx)
-BIGNUM *r;
-BIGNUM *a;
-BN_CTX *ctx;
+int BN_sqr(BIGNUM *r, const BIGNUM *a, BN_CTX *ctx)
         {
-        int i,j,max,al;
-        BIGNUM *tmp;
-        BN_ULONG *ap,*rp;
+        int max,al;
+        int ret = 0;
+        BIGNUM *tmp,*rr;
 
-        tmp=ctx->bn[ctx->tos];
+#ifdef BN_COUNT
+        fprintf(stderr,"BN_sqr %d * %d\n",a->top,a->top);
+#endif
+        bn_check_top(a);
 
         al=a->top;
-        if (al == 0)
+        if (al <= 0)
                 {
                 r->top=0;
                 return(1);
                 }
 
-        max=(al*2);
-        if (bn_wexpand(r,1+max) == NULL) return(0);
-        if (bn_wexpand(tmp,1+max) == NULL) return(0);
+        BN_CTX_start(ctx);
+        rr=(a != r) ? r : BN_CTX_get(ctx);
+        tmp=BN_CTX_get(ctx);
+        if (tmp == NULL) goto err;
 
-        r->neg=0;
+        max=(al+al);
+        if (bn_wexpand(rr,max+1) == NULL) goto err;
 
-        ap=a->d;
-        rp=r->d;
+        if (al == 4)
+                {
+#ifndef BN_SQR_COMBA
+                BN_ULONG t[8];
+                bn_sqr_normal(rr->d,a->d,4,t);
+#else
+                bn_sqr_comba4(rr->d,a->d);
+#endif
+                }
+        else if (al == 8)
+                {
+#ifndef BN_SQR_COMBA
+                BN_ULONG t[16];
+                bn_sqr_normal(rr->d,a->d,8,t);
+#else
+                bn_sqr_comba8(rr->d,a->d);
+#endif
+                }
+        else 
+                {
+#if defined(BN_RECURSION)
+                if (al < BN_SQR_RECURSIVE_SIZE_NORMAL)
+                        {
+                        BN_ULONG t[BN_SQR_RECURSIVE_SIZE_NORMAL*2];
+                        bn_sqr_normal(rr->d,a->d,al,t);
+                        }
+                else
+                        {
+                        int j,k;
+
+                        j=BN_num_bits_word((BN_ULONG)al);
+                        j=1<<(j-1);
+                        k=j+j;
+                        if (al == j)
+                                {
+                                if (bn_wexpand(tmp,k*2) == NULL) goto err;
+                                bn_sqr_recursive(rr->d,a->d,al,tmp->d);
+                                }
+                        else
+                                {
+                                if (bn_wexpand(tmp,max) == NULL) goto err;
+                                bn_sqr_normal(rr->d,a->d,al,tmp->d);
+                                }
+                        }
+#else
+                if (bn_wexpand(tmp,max) == NULL) goto err;
+                bn_sqr_normal(rr->d,a->d,al,tmp->d);
+#endif
+                }
+
+        rr->top=max;
+        rr->neg=0;
+        if ((max > 0) && (rr->d[max-1] == 0)) rr->top--;
+        if (rr != r) BN_copy(r,rr);
+        ret = 1;
+ err:
+        BN_CTX_end(ctx);
+        return(ret);
+        }
+
+/* tmp must have 2*n words */
+void bn_sqr_normal(BN_ULONG *r, const BN_ULONG *a, int n, BN_ULONG *tmp)
+        {
+        int i,j,max;
+        const BN_ULONG *ap;
+        BN_ULONG *rp;
+
+        max=n*2;
+        ap=a;
+        rp=r;
         rp[0]=rp[max-1]=0;
         rp++;
-        j=al;
+        j=n;
 
         if (--j > 0)
                 {
@@ -99,7 +169,7 @@ BN_CTX *ctx;
                 rp+=2;
                 }
 
-        for (i=2; i<al; i++)
+        for (i=n-2; i>0; i--)
                 {
                 j--;
                 ap++;
@@ -107,16 +177,112 @@ BN_CTX *ctx;
                 rp+=2;
                 }
 
-        bn_add_words(r->d,r->d,r->d,max);
+        bn_add_words(r,r,r,max);
 
         /* There will not be a carry */
 
-        bn_sqr_words(tmp->d,a->d,al);
+        bn_sqr_words(tmp,a,n);
 
-        bn_add_words(r->d,r->d,tmp->d,max);
-
-        r->top=max;
-        if (r->d[max-1] == 0) r->top--;
-        return(1);
+        bn_add_words(r,r,tmp,max);
         }
 
+#ifdef BN_RECURSION
+/* r is 2*n words in size,
+ * a and b are both n words in size.    (There's not actually a 'b' here ...)
+ * n must be a power of 2.
+ * We multiply and return the result.
+ * t must be 2*n words in size
+ * We calculate
+ * a[0]*b[0]
+ * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
+ * a[1]*b[1]
+ */
+void bn_sqr_recursive(BN_ULONG *r, const BN_ULONG *a, int n2, BN_ULONG *t)
+        {
+        int n=n2/2;
+        int zero,c1;
+        BN_ULONG ln,lo,*p;
+
+#ifdef BN_COUNT
+        fprintf(stderr," bn_sqr_recursive %d * %d\n",n2,n2);
+#endif
+        if (n2 == 4)
+                {
+#ifndef BN_SQR_COMBA
+                bn_sqr_normal(r,a,4,t);
+#else
+                bn_sqr_comba4(r,a);
+#endif
+                return;
+                }
+        else if (n2 == 8)
+                {
+#ifndef BN_SQR_COMBA
+                bn_sqr_normal(r,a,8,t);
+#else
+                bn_sqr_comba8(r,a);
+#endif
+                return;
+                }
+        if (n2 < BN_SQR_RECURSIVE_SIZE_NORMAL)
+                {
+                bn_sqr_normal(r,a,n2,t);
+                return;
+                }
+        /* r=(a[0]-a[1])*(a[1]-a[0]) */
+        c1=bn_cmp_words(a,&(a[n]),n);
+        zero=0;
+        if (c1 > 0)
+                bn_sub_words(t,a,&(a[n]),n);
+        else if (c1 < 0)
+                bn_sub_words(t,&(a[n]),a,n);
+        else
+                zero=1;
+
+        /* The result will always be negative unless it is zero */
+        p= &(t[n2*2]);
+
+        if (!zero)
+                bn_sqr_recursive(&(t[n2]),t,n,p);
+        else
+                memset(&(t[n2]),0,n2*sizeof(BN_ULONG));
+        bn_sqr_recursive(r,a,n,p);
+        bn_sqr_recursive(&(r[n2]),&(a[n]),n,p);
+
+        /* t[32] holds (a[0]-a[1])*(a[1]-a[0]), it is negative or zero
+         * r[10] holds (a[0]*b[0])
+         * r[32] holds (b[1]*b[1])
+         */
+
+        c1=(int)(bn_add_words(t,r,&(r[n2]),n2));
+
+        /* t[32] is negative */
+        c1-=(int)(bn_sub_words(&(t[n2]),t,&(t[n2]),n2));
+
+        /* t[32] holds (a[0]-a[1])*(a[1]-a[0])+(a[0]*a[0])+(a[1]*a[1])
+         * r[10] holds (a[0]*a[0])
+         * r[32] holds (a[1]*a[1])
+         * c1 holds the carry bits
+         */
+        c1+=(int)(bn_add_words(&(r[n]),&(r[n]),&(t[n2]),n2));
+        if (c1)
+                {
+                p= &(r[n+n2]);
+                lo= *p;
+                ln=(lo+c1)&BN_MASK2;
+                *p=ln;
+
+                /* The overflow will stop before we over write
+                 * words we should not overwrite */
+                if (ln < (BN_ULONG)c1)
+                        {
+                        do      {
+                                p++;
+                                lo= *p;
+                                ln=(lo+1)&BN_MASK2;
+                                *p=ln;
+                                } while (ln == 0);
+                        }
+                }
+        }
+#endif