fixed carry error on array add in HashDRBG

2014-11-13 18:08:23 -08:00
parent 6c2a238c9b
commit 2c85756130
1 changed files with 6 additions and 2 deletions
--- a/ctaocrypt/src/random.c
+++ b/ctaocrypt/src/random.c
@ -279,8 +279,12 @@ static INLINE void array_add(byte* d, word32 dLen, const byte* s, word32 sLen)
            d[dIdx] = carry;
            carry >>= 8;
        }
-        if (dIdx > 0)
-            d[dIdx] += carry;
+
+        for (; carry != 0 && dIdx >= 0; dIdx--) {
+            carry += d[dIdx];
+            d[dIdx] = carry;
+            carry >>= 8;
+        }
    }
 }