Subject: bug#40405: System log files are world readable

From: Diego Nicola Barbato <[email-masked]>
Date: Tue, 28 Apr 2020 15:11:47 +0200

Hi,

Ludovic Courtès <[email-masked]> writes:

> Hi,
>
> Ludovic Courtès <[email-masked]> skribis:
>
>> Diego Nicola Barbato <[email-masked]> skribis:
>>
>>>>>From 43c9ded791ce5b480504ce3528ee34578168f90e Mon Sep 17 00:00:00 2001
>>> From: Diego Nicola Barbato <[email-masked]>
>>> Date: Tue, 7 Apr 2020 13:58:28 +0200
>>> Subject: [PATCH 1/2] service: Create log files as non-world-readable.
>>>
>>> * modules/shepherd/service.scm (exec-command): Create log-file with file
>>>   permissions #o640.
>>
>> [...]
>>
>>>>>From e491436967a912e6e7372f582b3bf5c9784b8209 Mon Sep 17 00:00:00 2001
>>> From: Diego Nicola Barbato <[email-masked]>
>>> Date: Tue, 7 Apr 2020 13:38:47 +0200
>>> Subject: [PATCH 2/2] service: Add #:file-creation-mask to
>>>  'make-forkexec-constructor'.
>>>
>>> * modules/shepherd/service.scm (exec-command): Add #:file-creation-mask
>>>   parameter and honor it.
>>>   (fork+exec-command): Add #:file-creation-mask parameter and pass it to
>>>   exec-command.
>>>   (make-forkexec-constructor): Add #:file-creation-mask parameter and pass it
>>>   to fork+exec-command.
>>> * doc/shepherd.texi (Service De- and Constructors): Adjust accordingly.
>>
>> I went ahead and pushed these two patches.
>
> These patches are in Shepherd 0.8.0, which was pushed in Guix master
> commit e3358a831e7d5d9e8dc614340e49ea5aeb11a7ff, so we’re done!

Great!  Now we can simplify the 'start' method of
'syslogd-service-type'.

I did eventually write a test script, which I've attached in case we
want to add it to the Shepherd.  I'm sorry it took so long that I missed
the new Shepherd release.

Regards,

Diego

>From 2e7a0795b3a7080376238ab604c50d2c180f8730 Mon Sep 17 00:00:00 2001
From: Diego Nicola Barbato <[email-masked]>
Date: Mon, 27 Apr 2020 16:57:36 +0200
Subject: [PATCH] tests: Test #:file-creation-mask option of
 'make-forkexec-constructor'.

* tests/file-creation-mask.sh: New file.
---
 tests/file-creation-mask.sh | 79 +++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 tests/file-creation-mask.sh

diff --git a/tests/file-creation-mask.sh b/tests/file-creation-mask.sh
new file mode 100644
index 0000000..9f5f10a
--- /dev/null
+++ b/tests/file-creation-mask.sh
@@ -0,0 +1,79 @@
+# GNU Shepherd --- Test the #:file-creation-mask option of 'make-forkexec-constructor'.
+# Copyright © 2020 Diego N. Barbato <[email-masked]>
+#
+# This file is part of the GNU Shepherd.
+#
+# The GNU Shepherd is free software; you can redistribute it and/or modify it
+# under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or (at
+# your option) any later version.
+#
+# The GNU Shepherd is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with the GNU Shepherd.  If not, see <http://www.gnu.org/licenses/>.
+
+shepherd --version
+herd --version
+
+socket="t-socket-$$"
+conf="t-conf-$$"
+log="t-log-$$"
+pid="t-pid-$$"
+service_log="t-service-log-$$"
+service_new_file="t-service-new-file-$$"
+
+herd="herd -s $socket"
+
+trap "cat $log || true;
+      rm -f $socket $conf $log $service_log $service_new_file;
+      test -f $pid && kill \`cat $pid\` || true; rm -f $pid" EXIT
+
+function wait_for_file
+{
+    i=0
+    while ! test -f "$1" && test $i -lt 20
+    do
+	sleep 0.3
+	i=`expr $i + 1`
+    done
+    test -f "$1"
+}
+
+cat > "$conf"<<EOF
+(define %command
+  '("$SHELL" "-c" "touch $PWD/$service_new_file; echo foo"))
+
+(register-services
+ (make <service>
+   #:provides '(test)
+   #:start (make-forkexec-constructor %command
+                                      #:log-file "$PWD/$service_log"
+                                      ;; Set the umask such that file
+                                      ;; permissions are #o600.
+                                      #:file-creation-mask #o177)
+   #:stop (make-kill-destructor)
+   #:respawn? #f))
+EOF
+
+rm -f "$pid"
+shepherd -I -s "$socket" -c "$conf" -l "$log" --pid="$pid" &
+
+# Wait till it's ready.
+wait_for_file "$pid"
+
+# Start the service.
+$herd start test
+
+# Make sure the log file is created with the right permissions independently
+# of the value of #:file-creation-mask.
+wait_for_file "$service_log"
+test `stat -c %a "$service_log"` -eq 640
+
+# Make sure the service creates files with the right permissions as determined
+# by the value of #:file-creation-mask.
+wait_for_file "$service_new_file"
+test `stat -c %a "$service_new_file"` -eq 600
-- 
2.26.0