Skip to main content

DNS Custom Logs and selinux

If you google "named custom logs selinux" you will find quite a bit of chatter about setting up custom logs outside of /var/log for DNS (named). These posts are interesting, but they tend to be run on posts about learning selinux and becoming an expert on named.

What you need to know? If you have setup custom logging locations in your /etc/named.conf file, such as:

    channel default_file {
        file "/var/log/named/default.log" versions 3 size 5m;
        severity dynamic;
        print-time yes;
    };

Then you will likely see errors like this in /var/log/messages:

Oct 26 11:41:13 namedsvr setroubleshoot: SELinux is preventing /usr/sbin/named from write access on the directory /var/named/chroot/var/log/named. For complete SELinux messages. run sealert -l 6eab4aaf-e615-4ade-9e88-4efdc789eaf2

Then you run the sealert command as suggested by the very friendly selinux audit log and you are told:

#============= named_t ==============
#!!!! The source type 'named_t' can write to a 'dir' of the following types:
# tmp_t, named_cache_t, var_log_t, var_run_t, named_var_run_t, named_log_t, named_tmp_t, cluster_var_lib_t, cluster_var_run_t, root_t, cluster_conf_t

This is important information because your custom log locations are not labeled correctly, as in:

[root@namedsvr log]# ls -Z /var/named/chroot/var/log
drwxr-xr-x. named named unconfined_u:object_r:named_conf_t:s0 named

This named_conf_t type is very critical here. What you want to do now is change this type to be named_log_t:

chcon -t named_log_t /var/named/chroot/var/log/named

Restart named and error messages should go away.

Where did this named_conf_t type come from?

> more /etc/selinux/targeted/contexts/files/file_contexts

Run that more command see look at all of those labels. You want to find the named "chroot" labels and eventually work your way down to the /var/named/chroot/var/log paths. Then you want to add your own rule for the var/log/named path so that it sets the proper type to named_log_t. That way this change will survive reboot and restorecon, which is also very important.

A good place to start learning selinux:


Popular posts from this blog

Number of Primes

Anderson's Theorem (a) The number of primes in [1,n] is no more than 2+floor(n/2). The probability of n being prime when n is not prime is 1/2 - see Dasgupta,Papadimitriou,Vazirani "Algorithms" page 26. Therefore, the E(pi(n)) is n/2. (b) There does not exist another set of adjacent primes other than {1,2,3} 5: 2 + floor(5/2) = 2 + 2 = 4:=> {1,2,3,5} : 4 <= 4 7: 2 + floor(7/2) = 2 + 3 = 5 => {1,2,3,5,7} : 5 <= 5 11: 2 + floor(11/2) = 2 + 5 = 7 => {1,2,3,5,7,11} 6 <= 7 26: 2 + floor(26/2) = 15 => {1,2,3,5,7,11,13,17,19,23} : 10 <= 15 Lagrange's Theorem is Inaccurate Lagrange's theorem about primes states that pi(x) is the number of primes <= x. The pi(x) is approximately x/ln(x). He postulated that the lim of pi(x)/(x/lnx) as x-> infinity was 1. This is incorrect. if the number of primes is bounded by n/2 then refactoring and reducing Lagrange's Theorem results in the lim of ln(x) as x approaches infinity. This is alwa...
Read more

How To Cancel ATT Uverse

I was a subscriber to the AT&T Uverse service for a little over 2 years. In that time, we had experienced good service for the first year, and then it sucked. After 12 months, or there in, the service degraded quickly, and would stop working all together at times. At first it would die for a short period of time, usually when we were not home. Then it would get progressively worst, until there was an entire week of no service. We had technicians at the house trying to fix the service, but it would repeat the behavior quite consistently. On January 15th we finally gave up and switched to a lesser service, COX TV and Internet. In the past we had cable service and it was always reliable, but not as good as the AT&T digital service. COX doesn't have nearly as many HD channels, but that's not enough. We needed internet to be reliable, and AT&T couldn't deliver that. Cancelling the AT&T service was a nightmare. Try to find anything about such things on their web s...
Read more

AI or AI, Which Is It?

Artificial Intelligence, a noun that has become a household term. Most refer to it as AI, which is less of a mouthful. Where and when did this term become real? [1] Apparently John McCarthy coined this phrase in 1956 at a conference.  Vannevar Bush and Alan Turing both mused about computers being intelligence and being able to enhance human intelligence or even simulate human-like thinking. Is this thinking really "artificial" though? To suggest it being artificial would imply that there is a non-artificial type of intelligence. Otherwise, there is just intelligence, or thinking, or cognition.  The famous Turing Test may be the source of this "artificial" notion. If there is an intelligent series of responses to a human interaction, and those responses are created using a computer program, then that is considered artificial.  On a philosophical note, though, the programs are written by humans. Those programs, using rules given by humans, are creating responses that ...
Read more