spam.m4: Quote the arguments to the Userv service properly.

The Exim specification lies about how ${run ...} works.  We have to fix
this in post-production.

diff --git a/spam.m4 b/spam.m4
index 5d72365..c26abcf 100644 (file)
--- a/spam.m4
+++ b/spam.m4
@@ -25,6 +25,15 @@ DIVERT(null)
 ###--------------------------------------------------------------------------
 ### Spam filtering.
 
+## The Exim documentation tells lies.
+##
+## : *${run{*<_command_>* *<_args_>*}{*<_string1_>*}{*<_string2_>*}}*
+## :     The command and its arguments are first expanded separately, [...]
+##
+## They aren't.  The whole command-and-args are expanded together, and then
+## split at unquoted spaces.  This unpleasant hack sorts out the mess.
+m4_define(<:SHQUOTE:>, <:"${rxquote:$1}":>)
+
 SECTION(global, policy)m4_dnl
 spamd_address = CONF_spamd_address CONF_spamd_port
 
@@ -59,12 +68,12 @@ fetch_spam_limit:
                ${if and {{!eq{$acl_c_mode}{submission}} \
                          {exists {CONF_userconf_dir/spam-limit.userv}}} \
                     {${run {timeout 5s -- \
-                               userv $local_part exim-spam-limit \
-                                       $sender_address \
-                                       $local_part_prefix \
-                                       $local_part \
-                                       $local_part_suffix \
-                                       @$domain} \
+                               userv SHQUOTE($local_part) exim-spam-limit \
+                                       SHQUOTE($sender_address) \
+                                       SHQUOTE($local_part_prefix) \
+                                       SHQUOTE($local_part) \
+                                       SHQUOTE($local_part_suffix) \
+                                       SHQUOTE(@$domain)} \
                            {${if match{$value}{\N^-?[0-9]+$\N} \
                                  {spam_limit=$value} \
                                  {}}} \