From: Alex Dehnert <adehnert@mit.edu>
Date: Fri, 17 May 2013 06:31:04 +0000 (-0400)
Subject: krbroot: harden the shell settings
X-Git-Url: https://www.dehnerts.com/gitweb/?p=user%2Falex%2Fsoftware%2Fmy-snippets.git;a=commitdiff_plain;h=feda579ec7b7e241708573a22d8c66e571a6cafe

krbroot: harden the shell settings

See https://sipb.mit.edu/doc/safe-shell/ for the logic.
---

diff --git a/krbroot b/krbroot
index 5f0515d..37e0429 100755
--- a/krbroot
+++ b/krbroot
@@ -1,5 +1,7 @@
 #!/bin/sh
 
+set -euf
+
 usage="Usage: $0 [-i instance] [-p principal] [-a addrend] subcommand [args]"
 
 principal="$ATHENA_USER/root@ATHENA.MIT.EDU"
@@ -23,7 +25,7 @@ init () {
     kinit -F -5 -l15m "$principal" "$@"
 }
 
-case $1 in
+case ${1:-} in
     init)
         shift;
         exec kinit -F -5 -l15m "$principal" "$@"