Index: head/sys/libkern/iconv.c
===================================================================
--- head/sys/libkern/iconv.c
+++ head/sys/libkern/iconv.c
@@ -413,11 +413,11 @@
 		return EINVAL;
 	if (din.ia_datalen > ICONV_CSMAXDATALEN)
 		return EINVAL;
-	if (strlen(din.ia_from) >= ICONV_CSNMAXLEN)
+	if (strnlen(din.ia_from, sizeof(din.ia_from)) >= ICONV_CSNMAXLEN)
 		return EINVAL;
-	if (strlen(din.ia_to) >= ICONV_CSNMAXLEN)
+	if (strnlen(din.ia_to, sizeof(din.ia_to)) >= ICONV_CSNMAXLEN)
 		return EINVAL;
-	if (strlen(din.ia_converter) >= ICONV_CNVNMAXLEN)
+	if (strnlen(din.ia_converter, sizeof(din.ia_converter)) >= ICONV_CNVNMAXLEN)
 		return EINVAL;
 	if (iconv_lookupconv(din.ia_converter, &dcp) != 0)
 		return EINVAL;