From d24d241e099ad37804b26063ffdcf77427e32a50 Mon Sep 17 00:00:00 2001
Message-Id: <d24d241e099ad37804b26063ffdcf77427e32a50.1714023569.git.mdw@distorted.org.uk>
From: Mark Wooding <mdw@chiark.greenend.org.uk>
Date: Wed, 6 Feb 2013 00:28:38 +0000
Subject: [PATCH] bin/update: Check that the hostname is actually plausibly
 formed.
Organization: Straylight/Edgeware

From: Mark Wooding <mdw@distorted.org.uk>

I'm going to assume that nsupdate or something will complain if the DNS
length limits or whatever are exceeded.
---
 bin/update | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/bin/update b/bin/update
index a9c2716..957df07 100755
--- a/bin/update
+++ b/bin/update
@@ -31,6 +31,13 @@ doneargs='case $# in 0) ;; *) fail_usage ;; esac'
 checkhost () {
   host=$1
 
+  case "$host" in
+    *..* | .* | *. | *[!-_.a-zA-Z0-9]*)
+      echo >&2 "$0: invalid hostname"
+      exit 2
+      ;;
+  esac
+
   matchp=nil
   for pat in $DYNDNS_HOST; do
     case "$host" in $pat) matchp=t ;; esac
-- 
[mdw]