From: =?utf-8?b?T25kxZllaiBTdXLDvQ==?= <ondrej@debian.org>
Date: Thu, 14 May 2020 12:24:23 +0200
Subject: CVE-2020-8617

---
 lib/dns/tsig.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/lib/dns/tsig.c b/lib/dns/tsig.c
index a94ec69..ff40b99 100644
--- a/lib/dns/tsig.c
+++ b/lib/dns/tsig.c
@@ -1422,8 +1422,9 @@ dns_tsig_verify(isc_buffer_t *source, dns_message_t *msg,
 			goto cleanup_context;
 		}
 		msg->verified_sig = 1;
-	} else if (tsig.error != dns_tsigerror_badsig &&
-		   tsig.error != dns_tsigerror_badkey) {
+	} else if (!response || (tsig.error != dns_tsigerror_badsig &&
+				 tsig.error != dns_tsigerror_badkey))
+	{
 		tsig_log(msg->tsigkey, 2, "signature was empty");
 		return (DNS_R_TSIGVERIFYFAILURE);
 	}
@@ -1489,7 +1490,7 @@ dns_tsig_verify(isc_buffer_t *source, dns_message_t *msg,
 		}
 	}
 
-	if (tsig.error != dns_rcode_noerror) {
+	if (response && tsig.error != dns_rcode_noerror) {
 		msg->tsigstatus = tsig.error;
 		if (tsig.error == dns_tsigerror_badtime)
 			ret = DNS_R_CLOCKSKEW;