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[bug#44549] [PATCH] etc: updates for the guix-daemon SELinux policy
From: |
Marius Bakke |
Subject: |
[bug#44549] [PATCH] etc: updates for the guix-daemon SELinux policy |
Date: |
Fri, 13 Nov 2020 15:52:52 +0100 |
Daniel Brooks <db48x@db48x.net> writes:
>>>> + (allow guix_daemon_t
>>>> + guix_daemon_socket_t
>>>> + (sock_file (unlink)))
>>>
>>> That shouldn't be a problem, though we don't have any other rules for
>>> guix_daemon_socket_t. Possibly that is because my socket file is labeled
>>> guix_daemon_conf_t, for unknown reasons. Perhaps it was not labeled
>>> correctly when created, and hasn't been relabeled since.
>>
>> It could also be an artifact from my ancient experiments with Guix and
>> SELinux on this system. Perhaps we should test on a "clean" system to
>> verify, I can do that next week.
>
> Ok, I figured this one out. When the socket file is created it is
> labeled at guix_daemon_conf_t, but the filecon rules will cause that to
> be relabeled to guix_daemon_socket_t at some point in the future. When
> the guix-daemon process stops it tries to delete the socket file, but
> can't. I'll go ahead and include the rule.
OK.
>> As a side note, I've seen a couple other audit messages from
>> guix-daemon, although though they don't seem to cause a problem in
>> practice.
>>
>> type=AVC msg=audit(1605189801.627:8637388): avc: denied { read } for
>> pid=2312896 comm="guix-daemon" path="socket:[74336318]" dev="sockfs"
>> ino=74336318 scontext=system_u:system_r:guix_daemon.guix_daemon_t:s0
>> tcontext=system_u:system_r:init_t:s0 tclass=unix_stream_socket
>> permissive=0
>> type=AVC msg=audit(1605189801.627:8637388): avc: denied { read } for
>> pid=2312896 comm="guix-daemon" path="socket:[74336318]" dev="sockfs"
>> ino=74336318 scontext=system_u:system_r:guix_daemon.guix_daemon_t:s0
>> tcontext=system_u:system_r:init_t:s0 tclass=unix_stream_socket
>> permissive=0
>> type=AVC msg=audit(1605189801.627:8637388): avc: denied { siginh } for
>> pid=2312896 comm="guix-daemon" scontext=system_u:system_r:init_t:s0
>> tcontext=system_u:system_r:guix_daemon.guix_daemon_t:s0 tclass=process
>> permissive=0
>
> The first two are already covered by the new policy, and the third is
> inconsequential. The kernel checks on our behalf to see if our child
> processes are allowed to inherit our signal state. That's usually
> disallowed, so that rule is marked 'dontaudit' so that it doesn't spam
> the logs; you probably had that disabled. I'm not going to add a rule
> allowing that one; It would just cause accidents.
Thanks for investigating.
Interestingly, after updating the system (both RHEL8 and Guix) and
rebooting, I got new SELinux troubles!
I had to add these additional rules to make guix-daemon start again:
diff --git a/etc/guix-daemon.cil.in b/etc/guix-daemon.cil.in
index 47fd12a214..3e254a2187 100644
--- a/etc/guix-daemon.cil.in
+++ b/etc/guix-daemon.cil.in
@@ -86,12 +86,15 @@
(allow init_t
guix_daemon_t
(process (transition)))
+ (allow init_t
+ self
+ (process (execmem)))
(allow init_t
guix_store_content_t
(lnk_file (read)))
(allow init_t
guix_store_content_t
- (file (open read execute)))
+ (file (open read execute execute_no_trans map)))
;; guix-daemon needs to know the names of users
(allow guix_daemon_t
Do these look sane to you? I can squash them into the commit if so.
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[bug#44549] [PATCH v2] etc: updates for the guix-daemon SELinux policy, Daniel Brooks, 2020/11/12
[bug#44549] [PATCH v3] etc: updates for the guix-daemon SELinux policy, Daniel Brooks, 2020/11/12
[bug#44549] [PATCH v4] etc: updates for the guix-daemon SELinux policy, Daniel Brooks, 2020/11/14
[bug#44549] [PATCH v4] doc: add a note about relabling after upgrades to the guix deamon, Daniel Brooks, 2020/11/14