[refpolicy] Debian: ldd /sbin/udevd, need to use interactive fds

[martin@martinorr.name (Martin Orr)]

On 02/09/08 14:19, Christopher J. PeBenito wrote:
> On Mon, 2008-09-01 at 19:12 +0200, V?clav Ovs?k wrote:
>> I am running Debian unstable (Sid) with latest refpolicy packaged by
>> Russel Coker (2:0.0.20080702-6) with unconfined module (permissive
>> mode). I have caught problem with running update-initramfs under
>> unconfined user (system initrd image generation). The hook script udev
>> is trying to discover libraries used by udev running command "ldd
>> /sbin/udev", which emits:
>>
>> [  180.506850] type=1400 audit(1219673765.136:5): avc:  denied  { use } for  pid=1944 comm="udevd" path="/dev/tty1" dev=tmpfs ino=998 scontext=unconfined_u:system_r:udev_t:s0-s0:c0.c1023 tcontext=system_u:system_r:getty_t:s0 tclass=fd
>> [  180.534524] type=1300 audit(1219673765.136:5): arch=40000003 syscall=11 success=yes exit=0 a0=8f93ee8 a1=8f93e68 a2=8f7d008 a3=0 items=0 ppid=1936 pid=1944 auid=4294967295 uid=0 gid=0 euid=0 suid=0 fsuid=0 egid=0 sgid=0 fsgid=0 tty=tty1 ses=4294967295 comm="udevd" exe="/sbin/udevd" subj=unconfined_u:system_r:udev_t:s0-s0:c0.c1023 key=(null)
>>
>> One wants to see output from udevd --help e.g. also...
>> So attached is a patch.
> 
> The denials aren't consistent with 'ldd /sbin/udev', otherwise comm=
> would be ldd.  I also can't reproduce this type of denial while using
> ldd.  As for 'ldd --help', there shouldn't really be a transition.  In
> fact I think Dan may have suggested removing the domain transition from
> DIRECT_INITRC and just leave a role transition.

ldd is just a shell script, which does "LD_TRACE_LOADED_OBJECTS=1 $cmd" (you
can run that on the command line if you want).  Setting
LD_TRACE_LOADED_OBJECTS causes the dynamic linker to link the program and
output the objects it has linked but then exit without calling main().

Since $cmd is never properly executed, it doesn't make sense to be
transitioning to its domain.  So I think ldd should have a domain of its
own, which has no privileges except to write to the terminal and to
execute_no_trans everything.

-- 
Martin Orr