Two TODO comments taken care of. Nils pointed out that one of them had already
authorGeoff Thorpe <geoff@openssl.org>
Sun, 19 Sep 2004 04:43:46 +0000 (04:43 +0000)
committerGeoff Thorpe <geoff@openssl.org>
Sun, 19 Sep 2004 04:43:46 +0000 (04:43 +0000)
been done, and took care of the other one (which hadn't).

Submitted by: Nils Larsch
Reviewed by: Geoff Thorpe

crypto/bn/bn_ctx.c
crypto/bn/bn_print.c

index 12d8a8c..5bd742a 100644 (file)
  *
  * 1. Check a bunch of "(words+1)" type hacks in various bignum functions and
  * check they can be safely removed.
- *  - BN_bin2bn() looks pretty nasty with the miscellaneous +1 and +2 adjustments.
- *    Needs a full rubber-gloving, me thinks.
  *  - Check +1 and other ugliness in BN_from_montgomery()
- *  - Aspects of BN_bn2dec() also look a bit arbitrary
  *
  * 2. Consider allowing a BN_new_ex() that, at least, lets you specify an
  * appropriate 'block' size that will be honoured by bn_expand_internal() to
index 092322d..5fb8473 100644 (file)
@@ -102,14 +102,19 @@ err:
 /* Must 'OPENSSL_free' the returned data */
 char *BN_bn2dec(const BIGNUM *a)
        {
-       int i=0,num;
+       int i=0,num, ok = 0;
        char *buf=NULL;
        char *p;
        BIGNUM *t=NULL;
        BN_ULONG *bn_data=NULL,*lp;
 
+       /* get an upper bound for the length of the decimal integer
+        * num <= (BN_num_bits(a) + 1) * log(2)
+        *     <= 3 * BN_num_bits(a) * 0.1001 + log(2) + 1     (rounding error)
+        *     <= BN_num_bits(a)/10 + BN_num_bits/1000 + 1 + 1 
+        */
        i=BN_num_bits(a)*3;
-       num=(i/10+i/1000+3)+1;
+       num=(i/10+i/1000+1)+1;
        bn_data=(BN_ULONG *)OPENSSL_malloc((num/BN_DEC_NUM+1)*sizeof(BN_ULONG));
        buf=(char *)OPENSSL_malloc(num+3);
        if ((buf == NULL) || (bn_data == NULL))
@@ -122,7 +127,6 @@ char *BN_bn2dec(const BIGNUM *a)
 #define BUF_REMAIN (num+3 - (size_t)(p - buf))
        p=buf;
        lp=bn_data;
-       if (t->neg) *(p++)='-';
        if (BN_is_zero(t))
                {
                *(p++)='0';
@@ -130,6 +134,9 @@ char *BN_bn2dec(const BIGNUM *a)
                }
        else
                {
+               if (BN_get_sign(t))
+                       *p++ = '-';
+
                i=0;
                while (!BN_is_zero(t))
                        {
@@ -149,9 +156,16 @@ char *BN_bn2dec(const BIGNUM *a)
                        while (*p) p++;
                        }
                }
+       ok = 1;
 err:
        if (bn_data != NULL) OPENSSL_free(bn_data);
        if (t != NULL) BN_free(t);
+       if (!ok && buf)
+               {
+               OPENSSL_free(buf);
+               buf = NULL;
+               }
+
        return(buf);
        }