diff --git a/ChangeLog b/ChangeLog
index 02e1c31d6b..c78e65df2c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Fri Feb 15 15:23:12 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/iconv/iconv.c (iconv_convert): check upper bound.  a patch from
+	  Daniel Luz at [ruby-Bugs-17910].
+
 Fri Feb 15 10:35:54 2008  Nobuyoshi Nakada  <nobu@ruby-lang.org>
 
 	* re.c (rb_reg_quote): set US-ACII for ASCII-only string.
diff --git a/ext/iconv/iconv.c b/ext/iconv/iconv.c
index ed46234077..9f4c23b435 100644
--- a/ext/iconv/iconv.c
+++ b/ext/iconv/iconv.c
@@ -380,8 +380,11 @@ iconv_convert(iconv_t cd, VALUE str, int start, int length, int toidx, struct ic
 	    length = 0;
 	else if ((length -= start) < 0)
 	    length = 0;
-	else
+	else {
 	    inptr += start;
+	    if (length > slen)
+		length = slen;
+	}
     }
     instart = inptr;
     inlen = length;