From f4bdf5b37dab0d9f494ccf4cbe6a5abae6fdac6d Mon Sep 17 00:00:00 2001
From: Thomas Waldmann <tw@waldmann-edv.de>
Date: Sun, 14 Apr 2019 21:53:35 +0200
Subject: [PATCH] fix crash / add logging for reverse lookup on invalid ip
 address string

---
 src/nsupdate/main/dnstools.py | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/src/nsupdate/main/dnstools.py b/src/nsupdate/main/dnstools.py
index 431add9..fa10b3e 100644
--- a/src/nsupdate/main/dnstools.py
+++ b/src/nsupdate/main/dnstools.py
@@ -285,6 +285,10 @@ def rev_lookup(ipaddr):
             try:
                 return socket.gethostbyaddr(ipaddr)[0]
             except socket.error as err:
+                if err.errno in (-5, 4):
+                    # -5 / 4 == no address associated with hostname (invalid ip?)
+                    logger.warning("errno -5 when trying to reverse lookup %r" % ipaddr)
+                    break
                 if err.errno in (errno.EPERM, ):
                     # EPERM == 1 == unknown host
                     break