From 9510dbb57b8626a756d1b78ec763105c695460c3 Mon Sep 17 00:00:00 2001
From: Darren 'Tadgy' Austin <darren@afterdark.org.uk>
Date: Tue, 17 Nov 2020 23:26:45 +0000
Subject: Clean up syntax of host+domain entry and add some basic validation.

---
 netconfig | 70 ++++++++++++++++++++++++++++++++++++++-------------------------
 1 file changed, 42 insertions(+), 28 deletions(-)

diff --git a/netconfig b/netconfig
index 210c8a4..bad070e 100644
--- a/netconfig
+++ b/netconfig
@@ -425,47 +425,61 @@ PREFIX6=64
 
 # Main loop:
 while [ 0 ]; do
-cat << EOF > $TMP/tempmsg
+  cat << EOF > $TMP/tempmsg
 First, we'll need the name you'd like to give your host.
-Only the base hostname is needed right now. (not the domain)
+Only the base hostname is needed right now - not the domain.
+For example:  darkstar
 
 Enter hostname:
 EOF
- dialog --title "ENTER HOSTNAME" --inputbox "`cat $TMP/tempmsg`" 11 65 \
- $HOSTNM 2> $TMP/SeThost
- if [ $? = 1 -o $? = 255 ]; then
+  dialog --title "ENTER HOSTNAME" --inputbox "`cat $TMP/tempmsg`" 12 64 \
+      $HOSTNM 2> $TMP/SeThost
+  if [ $? = 1 -o $? = 255 ]; then
+    rm -f $TMP/SeThost $TMP/tempmsg
+    exit
+  fi
+  HOSTNM="`cat $TMP/SeThost`"
   rm -f $TMP/SeThost $TMP/tempmsg
-  exit
- fi
- HOSTNM="`cat $TMP/SeThost`"
- rm -f $TMP/SeThost $TMP/tempmsg
- if [ ! "$HOSTNM" = "" ]; then
-  break;
- fi
+  if [ "$HOSTNM" = "" ] || [[ ! "$HOSTNM" =~ ^[[:alnum:]]+(-)*[[:alnum:]]+$ ]]; then
+    dialog --title "HOSTNAME" --ok-button "Back" --msgbox \
+      "That doesn't appear to be a valid hostname.\n
+Hostnames can only contain letters, numbers and hyphens." 6 60
+    if [ $? = 1 -o $? = 255 ]; then
+      exit
+    fi
+  else
+    break
+  fi
 done
 
 while [ 0 ]; do
-cat << EOF > $TMP/tempmsg
+  cat << EOF > $TMP/tempmsg
 Now, we need the domain name for this machine, such as:
-
-example.org
-
+  example.org
 Do not supply a leading '.'
 
 Enter domain name for $HOSTNM: 
 EOF
- dialog --title "ENTER DOMAINNAME FOR '$HOSTNM'" --inputbox \
+  dialog --title "ENTER DOMAINNAME FOR '$HOSTNM'" --inputbox \
 "`cat $TMP/tempmsg`" \
-14 64 $DOMAIN 2> $TMP/SeTdom
- if [ $? = 1 -o $? = 255 ]; then
+12 59 $DOMAIN 2> $TMP/SeTdom
+  if [ $? = 1 -o $? = 255 ]; then
+    rm -f $TMP/SeTdom $TMP/tempmsg
+    exit
+  fi
+  DOMAIN="`cat $TMP/SeTdom`"
   rm -f $TMP/SeTdom $TMP/tempmsg
-  exit
- fi
- DOMAIN="`cat $TMP/SeTdom`"
- rm -f $TMP/SeTdom $TMP/tempmsg
- if [ ! "$DOMAIN" = "" ]; then
-  break;
- fi
+  # This regex doesn't catch everything, just basic syntax mistakes.
+  if [ "$DOMAIN" = "" ] || [[ ! "$DOMAIN" =~ ^([[:alnum:]]+[-.]*[[:alnum:]]+)+$ ]]; then
+    dialog --title "DOMAINNAME" --ok-button "Back" --msgbox \
+      "That doesn't appear to be a valid domain name.\n
+Domain names can only contain letters, numbers hyphens and dots." 6 68
+    if [ $? = 1 -o $? = 255 ]; then
+      exit
+    fi
+  else
+    break
+  fi
 done
 
 # Write the hostname with domain to /etc/HOSTNAME:
@@ -478,8 +492,8 @@ echo $HOSTNM.$DOMAIN > etc/HOSTNAME
 
 dialog --title "CONNECT VIA VLAN" --defaultno --yesno \
 "Some advanced networking set ups require a VLAN ID in order to \
-connect to the network.  Do you wish to configure a VLAN now? \n\n\
-Unless you are sure you require a VLAN, select 'No'." 8 68
+connect to the network.  Do you wish to configure a VLAN ID now?\n\n\
+Unless you are sure you require a VLAN ID, select 'No'." 8 68
 ERRNO="$?"
 if [ "$ERRNO" = "255" ]; then
   exit
-- 
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