* bignum.c (bigtrunc): RBIGNUM(x)->len may be zero. out of bound

  access.  [ruby-dev:31404]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_1_8@13069 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 1 insertions, 0 deletions

diff --git a/bignum.c b/bignum.c
index e49a18b118..e6ecb3933b 100644
--- a/bignum.c
+++ b/bignum.c
@@ -104,6 +104,7 @@ bigtrunc(x)
     long len = RBIGNUM(x)->len;
     BDIGIT *ds = BDIGITS(x);
 
+    if (len == 0) return x;
     while (--len && !ds[len]);
     RBIGNUM(x)->len = ++len;
     return x;