From ede71ac5d29c94d04f4cb16a504a61c157cc9add Mon Sep 17 00:00:00 2001
From: Brian Wellington <source@isc.org>
Date: Fri, 16 Feb 2001 00:04:18 +0000
Subject: [PATCH] fix suspicious (yet correct) use of strncat() in
 get_address() [RT #863]

---
 bin/dig/dighost.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/bin/dig/dighost.c b/bin/dig/dighost.c
index 503afcb39f..aa5f642d8a 100644
--- a/bin/dig/dighost.c
+++ b/bin/dig/dighost.c
@@ -15,7 +15,7 @@
  * WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
-/* $Id: dighost.c,v 1.190 2001/02/15 23:44:05 tamino Exp $ */
+/* $Id: dighost.c,v 1.191 2001/02/16 00:04:18 bwelling Exp $ */
 
 /*
  * Notice to programmers:  Do not use this code as an example of how to
@@ -207,6 +207,7 @@ isc_result_t
 get_reverse(char *reverse, char *value, isc_boolean_t nibble) {
 	int adrs[4];
 	char working[MXNAME];
+	int remaining;
 	int i, n;
 	isc_result_t result;
 
@@ -221,12 +222,15 @@ get_reverse(char *reverse, char *value, isc_boolean_t nibble) {
 		if (n == 0) {
 			return (DNS_R_BADDOTTEDQUAD);
 		}
+		reverse[MXNAME - 1] = 0;
 		for (i = n - 1; i >= 0; i--) {
-			snprintf(working, MXNAME/8, "%d.",
+			snprintf(working, sizeof(working), "%d.",
 				 adrs[i]);
-			strncat(reverse, working, MXNAME);
+			remaining = MXNAME - strlen(reverse) - 1;
+			strncat(reverse, working, remaining);
 		}
-		strncat(reverse, "in-addr.arpa.", MXNAME);
+		remaining = MXNAME - strlen(reverse) - 1;
+		strncat(reverse, "in-addr.arpa.", remaining);
 		result = ISC_R_SUCCESS;
 	} else if (strspn(value, "0123456789abcdefABCDEF:") 
 		   == strlen(value)) {