Procmail battles

Gregory P. Ennis PoMec at PoMec.Net
Mon May 15 13:56:31 UTC 2006


On Mon, 2006-05-15 at 10:35 +0100, Paul Howarth wrote:
> Gregory P. Ennis wrote:
> > On Sun, 2006-05-14 at 12:52 +0100, Paul Howarth wrote:
> >> On Sat, 2006-05-13 at 20:52 -0500, Gregory P. Ennis wrote:
> >>> On Sat, 2006-05-13 at 21:42 -0400, Paul Michael Reilly wrote:
> >>>> Les Mikesell <lesmikesell at gmail.com> writes:
> >>>>
> >>>>  > On Sat, 2006-05-13 at 14:48, Paul Michael Reilly wrote:
> >>>>  > 
> >>>>  > > LOGFILE=/root/procmail.log
> >>>>  > > LOGABSTRACT=yes
> >>>>  > > VERBOSE=1
> >>>>  > > 
> >>>>  > > and send mail to "root" then I actually see an abstract appended to
> >>>>  > > /root/procmail.log which is consistent with the procmail man page in
> >>>>  > > that it says $HOME/.procmailrc will get processed.  I leaped,
> >>>>  > > incorrectly it would appear, to the conclusion that $HOME referred to
> >>>>  > > the mail target.  It must be referring to the User running procmail,
> >>>>  > > i.e. "root" on a stock Fedora Core system, which makes considerable
> >>>>  > > sense.  This, I believe, is the crux of my battles.
> >>>>  > 
> >>>>  > $HOME is the expansion of the environment variable HOME, which
> >>>>  > is set to the 6th field of the user's /etc/passwd file entry,
> >>>>  > i.e. their home directory.  This happens in a straightforward
> >>>>  > way during logins and is emulated in procmail runs. 
> >>>>  > 
> >>>>  > > So that raises the question: how does one configure mail (sendmail or
> >>>>  > > otherwise) on a stock Fedora Core system so that ~User/.procmailrc
> >>>>  > > will be processed for all User's on the system?
> >>>>  > 
> >>>>  > ~user is expanded in a shell to the same thing as $HOME would be for
> >>>>  > that user.  Sendmail should, by default, use procmail for everyone
> >>>>  > which should then process their .procmailrc but it will not trust
> >>>>  > files where the permissions allow write access by others.
> >>>>
> >>>> Excellent.  This insight has led to the real culprit: selinux.
> >>>> Disabling selinux leads to FC4 level behavior so it is a safe bet that
> >>>> a more stringent FC5 selinux setting is what is ailing me.  Now,
> >>>> ideally, I should be able to google FC5, selinux and mail and get some
> >>>> insight.  Not so.  Anyone have a reference where I can learn what
> >>>> FC5 now expects from sendmail/procmail to make selinux happy?  The
> >>>> entries in /var/log/messages are not exactly real informative:
> >>>>
> >>>> May 13 21:22:04 roamer kernel: audit(1147569724.815:39): avc:  denied  { search } for  pid=26417 comm="procmail" name="log" dev=dm-0 ino=4128796 scontext=system_u:system_r:procmail_t:s0 tcontext=system_u:object_r:var_log_t:s0 tclass=dir
> >>>>
> >>>>
> >>>> -pmr
> >>>>
> >>> I am having the same problem with FC5 and selinux.  My system worked
> >>> fine with FC4 but is failing with FC5.  I am using procmail to store
> >>> spam in created directory ie /savedrwxr-xr-x  root     mail     root:object_r:root_t             .
> > 
> > 
> >> /home/$USER/Mail/spam.  When I turn
> >>> selinux off I can get procmail to work perfectly, but when I turn
> >>> selinux back on it fails to be able to write in this directory.  I know
> >>> very little about selinux and would appreciate some references as to
> >>> changes from FC4 to FC5 as well.
> >> The out-of-the-box selinux policy for FC5 was somewhat broken for
> >> procmail, particularly if you wanted to forward mail as an action.
> >>
> >> Paul, what log files are you trying to write, and what the the "adv:
> >> denial" messages you see in /var/log/messages when procmail tries to
> >> write to this log?
> >>
> >> Gregory, is /save/home/$USER the home directory for $USER?
> >> What's the output of:
> >> $ ls -laZ /save/home
> >>
> >> Paul.
> >>
> >>
> > Paul,
> > 
> > Thanks for your help.  Is there a way to modify the procmail policy in
> > selinux?
> > 
> > The above directory is not the home directory of the user.  When I
> > originally designed the software I created a directory system outside of
> > the /home, but $USER does represent the name of the user.  Here is a
> > partial listing of ls -laZ /save/home
> > 
> > drwxr-xr-x  root     root     root:object_r:root_t             ..
> > drwxr-xr-x  bkgrndch bkgrndch root:object_r:root_t             bkgrndchk
> > drwxr-xr-x  claire   claire   root:object_r:root_t             claire
> > drwxr-xr-x  clamav   clamav   root:object_r:root_t             clamav
> > drwxr-xr-x  greg     greg     root:object_r:root_t             greg
> > drwxr-xr-x  jesse    jesse    root:object_r:root_t             jesse
> > drwxr-xr-x  mail     mail     root:object_r:root_t             lost
> > +found
> > drwxr-xr-x  mailwoma mailwoma root:object_r:root_t             mailwoman
> > drwxr-xr-x  melissa  melissa  root:object_r:root_t             melissa
> > 
> > Thanks again for your help!
> 
> You can probably fix this with file context changes rather than policy 
> changes. Try this:
> 
> # chcon -Rh -t user_home_t /save/home/*
> # chcon -h -t user_home_dir_t /save/home/*
> 
> Paul.
> 
Everyone,

Thanks for all of your help.  This is becoming a good exercise to
understand selinux.  Paul... I will try your suggestion and let you
know.

Thanks again,

Greg




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