From 58d622d96dcb1a1d0b9a212782d329e60e24d1c3 Mon Sep 17 00:00:00 2001
From: Mark Andrews <marka@isc.org>
Date: Thu, 8 Sep 2016 11:34:19 +1000
Subject: [PATCH] 4462.   [bug]           Don't describe a returned EDNS COOKIE
 as "good"                         when there isn't a valid server cookie. [RT
 #43167]

---
 CHANGES           |  3 +++
 lib/dns/message.c | 15 ++++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/CHANGES b/CHANGES
index 0d3ff0dc35..56120a310d 100644
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,6 @@
+4462.	[bug]		Don't describe a returned EDNS COOKIE as "good"
+			when there isn't a valid server cookie. [RT #43167]
+
 4461.	[bug]		win32: not all external data was properly marked
 			as external data for windows dll. [RT #43161]
 
diff --git a/lib/dns/message.c b/lib/dns/message.c
index a4f52ea2e3..96f1bcb723 100644
--- a/lib/dns/message.c
+++ b/lib/dns/message.c
@@ -3426,8 +3426,21 @@ dns_message_pseudosectiontotext(dns_message_t *msg,
 				isc_buffer_forward(&optbuf, optlen);
 
 				if (optcode == DNS_OPT_COOKIE) {
-					if (msg->cc_ok)
+					/*
+					 * Valid server cookie?
+					 */
+					if (msg->cc_ok && optlen >= 16)
 						ADD_STRING(target, " (good)");
+					/*
+					 * Server cookie is not valid but
+					 * we had our cookie echoed back.
+					 */
+					if (msg->cc_ok && optlen < 16)
+						ADD_STRING(target, " (echoed)");
+					/*
+					 * We didn't get our cookie echoed
+					 * back.
+					 */
 					if (msg->cc_bad)
 						ADD_STRING(target, " (bad)");
 					ADD_STRING(target, "\n");