INSIST rdata.length < 65536 before using it in a call to isc_buffer_putuint16.

I was not entirely sure that all paths to the places where the INSISTS are
would have guaranteed that the unsigned int rdata.length was in the range
of an unsigned short.

lib/dns/dnssec.c

@@ -16,7 +16,7 @@
  */
 
 /*
- * $Id: dnssec.c,v 1.9 1999/10/11 15:15:38 bwelling Exp $
+ * $Id: dnssec.c,v 1.10 1999/10/17 21:33:03 tale Exp $
  * Principal Author: Brian Wellington
  */
 
@@ -335,7 +335,8 @@ dns_dnssec_sign(dns_name_t *name, dns_rdataset_t *set, dst_key_t *key,
 		/* Digest the length of the rdata */
 		isc_buffer_init(&lenbuf, &len, sizeof(len),
 				ISC_BUFFERTYPE_BINARY);
-		isc_buffer_putuint16(&lenbuf, rdatas[i].length);
+		INSIST(rdatas[i].length < 65536);
+		isc_buffer_putuint16(&lenbuf, (isc_uint16_t)rdatas[i].length);
 		isc_buffer_used(&lenbuf, &lenr);
 		ret = dst_sign(DST_SIGMODE_UPDATE, key, &ctx, &lenr, NULL);
 		if (ret != ISC_R_SUCCESS)
@@ -472,7 +473,8 @@ dns_dnssec_verify(dns_name_t *name, dns_rdataset_t *set, dst_key_t *key,
 		/* Digest the rdata length */
 		isc_buffer_init(&lenbuf, &len, sizeof(len),
 				ISC_BUFFERTYPE_BINARY);
-		isc_buffer_putuint16(&lenbuf, rdatas[i].length);
+		INSIST(rdatas[i].length < 65536);
+		isc_buffer_putuint16(&lenbuf, (isc_uint16_t)rdatas[i].length);
 		isc_buffer_used(&lenbuf, &lenr);
 
 		/* Digest the rdata */