Gentoo Archives: gentoo-hardened

From: petre rodan <kaiowas@g.o>
To: Andy Dustman <farcepest@×××××.com>
Cc: gentoo-hardened@l.g.o
Subject: Re: [gentoo-hardened] Re: Sysadmin clues needed for SELinux
Date: Tue, 16 Nov 2004 06:09:49
Message-Id: 4199A06A.8060501@gentoo.org
In Reply to: [gentoo-hardened] Re: Sysadmin clues needed for SELinux by Andy Dustman
1 Hi Andy,
2
3 Andy Dustman wrote:
4 > I had to tweak the apache2 policy a little bit so that SSL would work
5 > properl. The stock policy has:
6 >
7 > /var/cache/ssl.*\.sem -- system_u:object_r:httpd_cache_t
8 >
9 > I had to add:
10 >
11 > /var/cache/apache2 system_u:object_r:httpd_cache_t
12 > /var/cache/apache2/ssl.*\.sem system_u:object_r:httpd_cache_t
13
14 this is fixed in selinux-apache-20040925 (currently ~x86)
15
16 > /var/lib/ntp/ntp.drift wasn't being labelled correctly; I looks like
17 > this is fixed in the testing policy. I expect apache is probably fixed
18 > that way too.
19
20 yup. fixed in selinux-ntp-20041014.
21
22 > Of course, /root is not relabeled for root being a normal user. But
23 > then, if you do relabel it, it's has a context of
24 > system_u:object_r:default_t, which is not right either. su without the
25 > - works fine.
26
27 /root(/.*)? should end up root:object_r:sysadm_home_t, not default_t.
28
29 you should have in your users file a line like:
30 user root roles { sysadm_r staff_r };
31
32 if you recreate the file contexts
33 make -C /etc/security/selinux/src/policy reload contexts
34
35 you should end up with these 2 lines in /etc/security/selinux/src/policy/file_contexts/file_contexts:
36 /root -d root:object_r:sysadm_home_dir_t
37 /root/.+ root:object_r:sysadm_home_t
38
39 > However I suspect there is some more locking down to do
40 > to keep root from doing bad things like various denial-of-service
41 > attacks. Just as a example:
42 >
43 > # dd if=/dev/zero of=/tmp/foo
44
45 other then filling up the /tmp fs, I don't see what else it can do.
46
47 > This actually seems to lock up the machine in a bad way: An oops and a
48 > kernel panic: Fatal Exception in Interrupt Handler, starring Sharon
49 > Stone.
50
51 I can't reproduce this on my ext3 fs
52
53 > I have a separate XFS /tmp filesystem, running
54 > hardened-dev-sources. I could probably reproduce this, but won't...
55
56 > Maybe there should be a guest_r role (or punk_r) for users we really
57 > don't want to do anything?
58
59 if they are not permitted to do anything, they shouldn't have received an account in the first place. :)
60
61 bye,
62 peter
63
64 --
65 petre rodan
66 <kaiowas@g.o>
67 Developer,
68 Hardened Gentoo Linux

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Re: [gentoo-hardened] Re: Sysadmin clues needed for SELinux Andy Dustman <farcepest@×××××.com>