From fe271c5672afdb136edb15d1717b54f60c315992 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Marczykowski-G=C3=B3recki?=
 <marmarek@invisiblethingslab.com>
Date: Mon, 19 Feb 2018 02:26:02 +0100
Subject: [PATCH] qubespolicy: use '@' instead of '$' for policy keywords

Using '$' is easy to misuse in shell scripts, shell commands etc. After
all this years, lets abandon this dangerous character and move to
something safer: '@'. The choice was made after reviewing specifications
of various shells on different operating systems and this is the
character that have no special meaning in none of them.

To preserve compatibility, automatically translate '$' to '@' when
loading policy files.
---
 qrexec/qrexec-policy | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/qrexec/qrexec-policy b/qrexec/qrexec-policy
index 15921f7..db6dde4 100755
--- a/qrexec/qrexec-policy
+++ b/qrexec/qrexec-policy
@@ -63,6 +63,7 @@ def read_policy_file(service_name):
     f = open(policy_file)
     fcntl.flock(f, fcntl.LOCK_SH)
     for iter in f.readlines():
+        iter = iter.replace('$', '@')
         dict = line_to_dict(iter)
         if dict is not None:
             policy_list.append(dict)
@@ -70,7 +71,7 @@ def read_policy_file(service_name):
     return policy_list
 
 def is_match(item, config_term):
-    return (item != "dom0" and config_term == "$anyvm") or item == config_term
+    return (item != "dom0" and config_term == "@anyvm") or item == config_term
 
 def get_default_policy():
     dict={}
@@ -89,7 +90,7 @@ def find_policy(policy, domain, target):
 
 def validate_target(target):
     # special targets
-    if target in ['$dispvm']:
+    if target in ['@dispvm']:
         return True
 
     qc = QubesVmCollection()
@@ -110,7 +111,7 @@ def spawn_target_if_necessary(vm):
     null.close()
 
 def do_execute(domain, target, user, service_name, process_ident, vm=None):
-    if target == "$dispvm":
+    if target == "@dispvm":
         cmd = "/usr/lib/qubes/qfile-daemon-dvm " + service_name + " " + domain + " " +user
         os.execl(QREXEC_CLIENT, "qrexec-client",
                 "-d", "dom0", "-c", process_ident, cmd)
@@ -179,11 +180,11 @@ def create_policy(service_name):
     policyFile = "/etc/qubes-rpc/policy/"+service_name
     policy = open(policyFile, "w")
     policy.write("## Note that policy parsing stops at the first match,\n")
-    policy.write("## so adding anything below \"$anyvm $anyvm action\" line will have no effect\n")
+    policy.write("## so adding anything below \"@anyvm @anyvm action\" line will have no effect\n")
     policy.write("\n")
     policy.write("## Please use a single # to start your custom comments\n")
     policy.write("\n")
-    policy.write("$anyvm  $anyvm  ask\n")
+    policy.write("@anyvm  @anyvm  ask\n")
     policy.close()
 
 def main():