On Tue, 15 Jan 2008 14:53:18 -0500 Daniel J Walsh dwalsh@redhat.com wrote:
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Paul Howarth wrote:
Daniel J Walsh wrote:
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Paul Howarth wrote:
Daniel J Walsh wrote:
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Paul Howarth wrote:
Hi Dan,
Daniel J Walsh wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Paul Howarth wrote: >> Paul Howarth wrote: >>> Since upgrading my mail server from Fedora 7 to Fedora 8, >>> I've come across some problems with the sockets used for >>> communication between >>> sendmail and two of the "milter" plugins I'm using with it, >>> namely milter-regex and spamass-milter. It's very likely >>> that other milters >>> will have similar issues. >>> >>> The sockets used are created when the milter starts, as >>> follows: >>> >>> milter-regex: >>> /var/spool/milter-regex/sock (var_spool_t, inherited from >>> parent directory) >>> >>> spamass-milter: >>> /var/run/spamass-milter/spamass-milter.sock >>> (spamd_var_run_t, in policy) >>> >>> These are pretty well the upstream locations, though I'm >>> open to moving the milter-regex socket from /var/spool >>> to /var/run or elsewhere for consistency. >>> >>> Since moving to Fedora 8, I've had to add the following to >>> local policy to get these milters working: >>> >>> allow sendmail_t spamd_var_run_t:dir { search getattr }; >>> allow sendmail_t spamd_var_run_t:sock_file { getattr write }; >>> allow sendmail_t var_spool_t:sock_file { getattr write }; >>> allow sendmail_t initrc_t:unix_stream_socket { read write >>> connectto }; >>> >>> The last of these is the strangest, and relates to Bug >>> #425958 >>> (https://bugzilla.redhat.com/show_bug.cgi?id=425958). Whilst >>> the socket file itself has the context listed above, the >>> unix domain socket that sendmail connects to is still >>> initrc_t, as can be seen from the output of "netstat -lpZ": >>> >>> ... >>> unix 2 [ ACC ] STREAM LISTENING 14142 >>> 5853/spamass-milter system_u:system_r:initrc_t:s0 >>> /var/run/spamass-milter/spamass-milter.sock >>> unix 2 [ ACC ] STREAM LISTENING 13794 >>> 5779/milter-regex system_u:system_r:initrc_t:s0 >>> /var/spool/milter-regex/sock >>> ... >>> >>> So, my questions are: >>> >>> 1. Why are the sockets still initrc_t? >>> 2. Is this a kernel issue or a userspace issue that should be >>> fixed in >>> the milters? >>> 3. Should there be a standard place for milter sockets to >>> live, and if >>> so, where? >>> 4. How come this worked OK in Fedora 7 and previous releases? >> Looking at the source code for these applications, I see that >> both of >> them use the smfi_setconn() function in the sendmail milter >> library to >> set up the sockets. It's therefore likely that this problem is >> common to >> all milter applications that use unix domain sockets. >> >> I'm now of the opinion that moving the directory locations >> for these sockets is a bad idea - it would need corresponding >> changes in people's >> sendmail configuration files, which would lead to problems for >> people >> doing package updates, or installing from upstream sources. >> Setting different context types for the directories (e.g. make >> /var/spool/milter-regex spamd_var_run_t) would seem a better >> option, along with policy tweaks to allow sendmail to do the >> permissions checks >> and write to the sockets). >> >> I'm still confused about the initrc_t sockets though. >> >> Paul. >> >> -- >> fedora-selinux-list mailing list >> fedora-selinux-list@redhat.com >> https://www.redhat.com/mailman/listinfo/fedora-selinux-list > Ok I will add this to the next update. What exactly is "this"? The 4 "allow" rules mentioned above, the context type change for /var/spool/milter-regex mentioned later, both?
Cheers, Paul.
Context change for /var/spool/milter-regex to spamd_var_run_t. sendmail can already use sockets in this directory.
So that includes the:
allow sendmail_t initrc_t:unix_stream_socket { read write connectto }
?
Cheers, Paul.
Nope. I don't know what is running as initrc_t and I would bet this is a leaked file descriptor. Or at least a redirectiron of stdin/stdout.
I don't think it's a leaked file descriptor - that would be dontaudit-able, right? By not allowing communications with the initrc_t:unix_stream_socket, the milter fails to work:
==> /var/log/audit/audit.log <== type=AVC msg=audit(1200408212.783:142453): avc: denied { connectto } for pid=7805 comm="sendmail" path="/var/spool/milter-regex/sock" scontext=system_u:system_r:sendmail_t:s0 tcontext=system_u:system_r:initrc_t:s0 tclass=unix_stream_socket type=SYSCALL msg=audit(1200408212.783:142453): arch=40000003 syscall=102 success=no exit=-13 a0=3 a1=bfd9f600 a2=b7f79bd4 a3=0 items=0 ppid=7764 pid=7805 auid=0 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=51 sgid=51 fsgid=51 tty=(none) comm="sendmail" exe="/usr/sbin/sendmail.sendmail" subj=system_u:system_r:sendmail_t:s0 key=(null)
==> /var/log/maillog <== Jan 15 14:43:32 goalkeeper sendmail[7805]: NOQUEUE: connect from ard120.neoplus.adsl.tpnet.pl [83.26.189.120] Jan 15 14:43:32 goalkeeper sendmail[7805]: AUTH: available mech=CRAM-MD5 DIGEST-MD5, allowed mech=CRAM-MD5 DIGEST-MD5 LOGIN PLAIN Jan 15 14:43:32 goalkeeper sendmail[7805]: m0FEhW21007805: Milter (milter-regex): error connecting to filter: Permission denied Jan 15 14:43:32 goalkeeper sendmail[7805]: m0FEhW21007805: Milter (milter-regex): to error state Jan 15 14:43:32 goalkeeper sendmail[7805]: m0FEhW21007805: Milter: initialization failed, temp failing commands Jan 15 14:43:32 goalkeeper sendmail[7805]: m0FEhW21007805: SMTP MAIL command (pathrusim@zombanewmedia.com) from ard120.neoplus.adsl.tpnet.pl [83.26.189.120] tempfailed (due to previous checks)
The initrc_t type shows up in netstat but not in ls: # netstat -aZp | grep initrc tcp 0 0 goalkeeper.intra.:bacula-fd *:* LISTEN 5864/bacula-fd system_u:system_r:initrc_t:s0 udp 0 0 rbldns.intra.cit:domain *:* 5885/rbldnsd system_u:system_r:initrc_t:s0 unix 2 [ ACC ] STREAM LISTENING 14142 5853/spamass-milter system_u:system_r:initrc_t:s0 /var/run/spamass-milter/spamass-milter.sock unix 2 [ ACC ] STREAM LISTENING 13794 5779/milter-regex system_u:system_r:initrc_t:s0 /var/spool/milter-regex/sock unix 2 [ ] DGRAM 2150436 5779/milter-regex system_u:system_r:initrc_t:s0 unix 2 [ ] DGRAM 14141 5853/spamass-milter system_u:system_r:initrc_t:s0 # ls -lZ /var/run/spamass-milter/spamass-milter.sock /var/spool/milter-regex/sock srwxr-xr-x sa-milt sa-milt system_u:object_r:spamd_var_run_t:s0 /var/run/spamass-milter/spamass-milter.sock srw------- mregex mregex system_u:object_r:spamd_var_run_t:s0 /var/spool/milter-regex/sock
Paul.
Ok then I guess we need to label
chcon -t spamd_exec_t /usr/sbin/spamass-milter
And then build policy off of that.
Whilst that might result in a solution for spamass-milter, it's not going to help milter-regex or potentially any other milter (they're all likely to use the same libmilter [sendmail] API for setting up the sockets).
There seems to be something odd about sockets in general; the netstat output quoted above shows a couple of network-listening sockets with type initrc_t too, from a further two non-milter programs, namely bacula and rbldnsd. I also see the same issue with nasd and rpc.quotad. though I can also see a bunch of listening sockets with system_u:system_r:unconfined_t on my desktop.
Why might some of these apps transition to unconfined_t and others not?
And why does "ls" show a different type than "netstat"?
Paul.