PR: 2111

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

diff --git a/crypto/bn/bn_mul.c b/crypto/bn/bn_mul.c
index fd598b8b3d61fd1212890bcc583a1a98f3f2ce8f..a0e9ec3b4694cb896a565f2953c56f53eef1da1c 100644 (file)
--- a/crypto/bn/bn_mul.c
+++ b/crypto/bn/bn_mul.c
@@ -66,7 +66,7 @@
 #include "cryptlib.h"
 #include "bn_lcl.h"
 
-#if defined(OPENSSL_NO_ASM) || !(defined(__i386) || defined(__i386__))/* Assembler implementation exists only for x86 */
+#if defined(OPENSSL_NO_ASM) || !defined(OPENSSL_BN_ASM_PART_WORDS)
 /* Here follows specialised variants of bn_add_words() and
    bn_sub_words().  They have the property performing operations on
    arrays of different sizes.  The sizes of those arrays is expressed through
@@ -389,6 +389,7 @@ BN_ULONG bn_add_part_words(BN_ULONG *r,
  * a[0]*b[0]+a[1]*b[1]+(a[0]-a[1])*(b[1]-b[0])
  * a[1]*b[1]
  */
+/* dnX may not be positive, but n2/2+dnX has to be */
 void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
        int dna, int dnb, BN_ULONG *t)
        {
@@ -398,7 +399,7 @@ void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
        BN_ULONG ln,lo,*p;
 
 # ifdef BN_COUNT
-       fprintf(stderr," bn_mul_recursive %d * %d\n",n2,n2);
+       fprintf(stderr," bn_mul_recursive %d%+d * %d%+d\n",n2,dna,n2,dnb);
 # endif
 # ifdef BN_MUL_COMBA
 #  if 0
@@ -545,16 +546,17 @@ void bn_mul_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n2,
 
 /* n+tn is the word length
  * t needs to be n*4 is size, as does r */
+/* tnX may not be negative but less than n */
 void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n,
             int tna, int tnb, BN_ULONG *t)
        {
        int i,j,n2=n*2;
-       unsigned int c1,c2,neg,zero;
+       int c1,c2,neg,zero;
        BN_ULONG ln,lo,*p;
 
 # ifdef BN_COUNT
-       fprintf(stderr," bn_mul_part_recursive (%d+%d) * (%d+%d)\n",
-               tna, n, tnb, n);
+       fprintf(stderr," bn_mul_part_recursive (%d%+d) * (%d%+d)\n",
+               n, tna, n, tnb);
 # endif
        if (n < 8)
                {
@@ -655,14 +657,17 @@ void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n,
                                for (;;)
                                        {
                                        i/=2;
-                                       if (i < tna && i < tnb)
+                                       /* these simplified conditions work
+                                        * exclusively because difference
+                                        * between tna and tnb is 1 or 0 */
+                                       if (i < tna || i < tnb)
                                                {
                                                bn_mul_part_recursive(&(r[n2]),
                                                        &(a[n]),&(b[n]),
                                                        i,tna-i,tnb-i,p);
                                                break;
                                                }
-                                       else if (i <= tna && i <= tnb)
+                                       else if (i == tna || i == tnb)
                                                {
                                                bn_mul_recursive(&(r[n2]),
                                                        &(a[n]),&(b[n]),
@@ -706,7 +711,7 @@ void bn_mul_part_recursive(BN_ULONG *r, BN_ULONG *a, BN_ULONG *b, int n,
 
                /* The overflow will stop before we over write
                 * words we should not overwrite */
-               if (ln < c1)
+               if (ln < (BN_ULONG)c1)
                        {
                        do      {
                                p++;
@@ -964,7 +969,7 @@ int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
 
        if ((al == 0) || (bl == 0))
                {
-               if (!BN_zero(r)) goto err;
+               BN_zero(r);
                return(1);
                }
        top=al+bl;
@@ -1023,17 +1028,19 @@ int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
                        assert(j <= al || j <= bl);
                        k = j+j;
                        t = BN_CTX_get(ctx);
+                       if (t == NULL)
+                               goto err;
                        if (al > j || bl > j)
                                {
-                               bn_wexpand(t,k*4);
-                               bn_wexpand(rr,k*4);
+                               if (bn_wexpand(t,k*4) == NULL) goto err;
+                               if (bn_wexpand(rr,k*4) == NULL) goto err;
                                bn_mul_part_recursive(rr->d,a->d,b->d,
                                        j,al-j,bl-j,t->d);
                                }
                        else    /* al <= j || bl <= j */
                                {
-                               bn_wexpand(t,k*2);
-                               bn_wexpand(rr,k*2);
+                               if (bn_wexpand(t,k*2) == NULL) goto err;
+                               if (bn_wexpand(rr,k*2) == NULL) goto err;
                                bn_mul_recursive(rr->d,a->d,b->d,
                                        j,al-j,bl-j,t->d);
                                }
@@ -1090,10 +1097,11 @@ int BN_mul(BIGNUM *r, const BIGNUM *a, const BIGNUM *b, BN_CTX *ctx)
 #if defined(BN_MUL_COMBA) || defined(BN_RECURSION)
 end:
 #endif
-       bn_fix_top(rr);
+       bn_correct_top(rr);
        if (r != rr) BN_copy(r,rr);
        ret=1;
 err:
+       bn_check_top(r);
        BN_CTX_end(ctx);
        return(ret);
        }