-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 02/20/2011 06:31 AM, Scott Gifford wrote: > On Mon, Jan 17, 2011 at 11:27 PM, Scott Gifford > <sgifford@xxxxxxxxxxxxxxxx>wrote: > >> On Mon, Jan 17, 2011 at 2:45 PM, Daniel J Walsh <dwalsh@xxxxxxxxxx> wrote: >> [ ... ] >> >>> > Third, since my main goal here is to prevent processes from interacting >>> with >>>> each other inappropriately, I would like to prevent each HTTP worker >>> from >>>> reading any information from "/proc" for other HTTP workers. Currently >>> they >>>> are allowed to do this, because they all run in the same domain. Is >>> there >>>> any way to prevent this? >>>> >>> >>> libvirt and sandbox use MCS separation for this. Basically they grab >>> random MCS labels to separate the processes. I would suggest using two >>> Categories, s0:c0-c1023,c0-1023 and make sure they are never the same. >>> >>> s0:c1,c43 >>> s0:c2,c43 >>> >>> Is fine. >>> >>> s0:c1,c1 is not >>> >>> Then just set that context and you should get separation. if you need >>> the processes to handle data it might get a little more complicated. >>> >> >> Thanks! I think I will need to learn a little more about this feature >> before I can use it. I will need a way to generate a unique category number >> (maybe from the PID?), and the processes will need to handle some shared >> data and code, so I will need to figure that out as well. >> > > OK, so I have started experimenting with this, but /proc is not behaving how > I expect so far. > > So I open up two shells. In the first I run: > > runcon -l s0-s0:c0,c1 bash > > > and in the second: > > runcon -l s0-s0:c0,c2 bash > > > So both should have access to c1, but only the first will have access to c1 > and only the second will have access to c2. s0-s0:c0,c2 should not have access to c1 but s0-s0:c0,c2 should > When I try this on files, it works: > > shell1$ *id -Z* > user_u:system_r:unconfined_t:-s0:c0,c1 > shell1$ *ls -lZ test.c1 test.c2* > -rw-rw-r-- sgifford sgifford user_u:object_r:user_home_t:s0:c1 test.c1 > -rw-rw-r-- sgifford sgifford user_u:object_r:user_home_t:s0:c2 test.c2 > shell1$ *head -1 test.c1 test.c2* > ==> test.c1 <== > Category 1 > head: cannot open `test.c2' for reading: Permission denied > > > But on /proc files it does not: > > shell1$ *id -Z* > user_u:system_r:unconfined_t:-s0:c0,c1 > shell1$ *ls -lZ /proc/10961/maps* > -r--r--r-- sgifford sgifford user_u:system_r:unconfined_t:-s0:c0,c2 > /proc/10961/maps > shell1$ *head -1 /proc/10961/maps* > 002ac000-002ad000 r-xp 002ac000 00:00 0 [vdso] from /policy/mcs: # Note: # - getattr on dirs/files is not constrained. # - /proc/pid operations are not constrained. so that explains the above > > That is, even though "ls -lZ" indicates that the maps file for PID 10961 > requires c2 and my shell does not have c2, still I am allowed to read this > file. > > I must be misunderstanding something here. Any thoughts or hints? > > Thanks! > > -----Scott. > > > > > -- > selinux mailing list > selinux@xxxxxxxxxxxxxxxxxxxxxxx > https://admin.fedoraproject.org/mailman/listinfo/selinux -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/ iEYEARECAAYFAk1hSIMACgkQMlxVo39jgT/QQwCdHdLejp+yQNogRF/3v7AcxjX8 Mj8AnirFnUpfJqXVJOHsCZb37o3rtYU6 =DEMM -----END PGP SIGNATURE----- -- selinux mailing list selinux@xxxxxxxxxxxxxxxxxxxxxxx https://admin.fedoraproject.org/mailman/listinfo/selinux
