Fix math in BN_bn2dec comment.

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

diff --git a/crypto/bn/bn_print.c b/crypto/bn/bn_print.c
index 8672c7e3b32036f9b9b0b4eaac3aa16c295c7427..39fb03412e5569eb77400129ce4670dbee7afb82 100644 (file)
--- a/crypto/bn/bn_print.c
+++ b/crypto/bn/bn_print.c
@@ -62,16 +62,18 @@ char *BN_bn2dec(const BIGNUM *a)
     char *p;
     BIGNUM *t = NULL;
     BN_ULONG *bn_data = NULL, *lp;
+    int bn_data_num;
 
     /*-
      * 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
+     *     <= 3 * BN_num_bits(a) * 0.101 + log(2) + 1     (rounding error)
+     *     <= 3 * BN_num_bits(a) / 10 + 3 * BN_num_bits / 1000 + 1 + 1
      */
     i = BN_num_bits(a) * 3;
     num = (i / 10 + i / 1000 + 1) + 1;
-    bn_data = OPENSSL_malloc((num / BN_DEC_NUM + 1) * sizeof(BN_ULONG));
+    bn_data_num = num / BN_DEC_NUM + 1;
+    bn_data = OPENSSL_malloc(bn_data_num * sizeof(BN_ULONG));
     buf = OPENSSL_malloc(num + 3);
     if ((buf == NULL) || (bn_data == NULL)) {
         BNerr(BN_F_BN_BN2DEC, ERR_R_MALLOC_FAILURE);
@@ -90,9 +92,12 @@ char *BN_bn2dec(const BIGNUM *a)
         if (BN_is_negative(t))
             *p++ = '-';
 
-        i = 0;
         while (!BN_is_zero(t)) {
+            if (lp - bn_data >= bn_data_num)
+                goto err;
             *lp = BN_div_word(t, BN_DEC_CONV);
+            if (*lp == (BN_ULONG)-1)
+                goto err;
             lp++;
         }
         lp--;