From: domg472@gmail.com (Dominick Grift) Date: Thu, 27 Jan 2011 21:42:18 +0100 Subject: [refpolicy] [PATCH/RFC 8/19]: patch set to update the git reference policy In-Reply-To: <1296160570.12677.7.camel@tesla.lan> References: <1295829851.3862.67.camel@tesla.lan> <4D3D8703.8040308@gmail.com> <1295982348.11770.16.camel@tesla.lan> <4D3F2245.9090606@gmail.com> <1296002515.16768.18.camel@tesla.lan> <4D3FD8B5.9030306@gmail.com> <1296062881.3028.18.camel@tesla.lan> <4D405B81.9050608@gmail.com> <1296088632.15344.34.camel@tesla.lan> <4D4137E9.9050805@gmail.com> <1296160570.12677.7.camel@tesla.lan> Message-ID: <4D41D8AA.2020707@gmail.com> To: refpolicy@oss.tresys.com List-Id: refpolicy.oss.tresys.com -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 01/27/2011 09:36 PM, Guido Trentalancia wrote: > Hello Dominick ! > > On Thu, 27/01/2011 at 10.16 +0100, Dominick Grift wrote: >> On 01/27/2011 01:37 AM, Guido Trentalancia wrote: >>> On Wed, 26/01/2011 at 18.36 +0100, Dominick Grift wrote: >>>> On 01/26/2011 06:28 PM, Guido Trentalancia wrote: >>>>> Hello Dominick ! >>>>> >>>>> On Wed, 26/01/2011 at 09.17 +0100, Dominick Grift wrote: >>>>>> On 01/26/2011 01:41 AM, Guido Trentalancia wrote: >>>>>>> On Tue, 25/01/2011 at 20.19 +0100, Dominick Grift wrote: >>>>>>>> On 01/25/2011 08:05 PM, Guido Trentalancia wrote: >>>>>>>>> Hi Dominick, >>>>>>>>> >>>>>>>>> finally I am managing to get into this... >>>>>>>>> >>>>>>>>> On Mon, 24/01/2011 at 15.04 +0100, Dominick Grift wrote: >>>>>>>>>> On 01/24/2011 01:44 AM, Guido Trentalancia wrote: >>>>>>>>>>> --- refpolicy-git-18012011-dbus-messaging/policy/modules/services/dbus.te 2011-01-23 23:13:48.168284256 +0100 >>>>>>>>>>> +++ refpolicy-git-18012011-dbus/policy/modules/services/dbus.te 2011-01-23 23:11:46.430346876 +0100 >>>>>>>>>>> @@ -52,7 +52,7 @@ ifdef(`enable_mls',` >>>>>>>>>>> >>>>>>>>>>> # dac_override: /var/run/dbus is owned by messagebus on Debian >>>>>>>>>>> # cjp: dac_override should probably go in a distro_debian >>>>>>>>>>> -allow system_dbusd_t self:capability { dac_override setgid setpcap setuid }; >>>>>>>>>>> +allow system_dbusd_t self:capability { dac_override setgid setpcap setuid sys_ptrace }; >>>>>>>>>>> dontaudit system_dbusd_t self:capability sys_tty_config; >>>>>>>>>>> allow system_dbusd_t self:process { getattr getsched signal_perms setpgid getcap setcap }; >>>>>>>>>>> allow system_dbusd_t self:fifo_file rw_fifo_file_perms; >>>>>>>>>>> @@ -111,13 +111,20 @@ auth_read_pam_console_data(system_dbusd_ >>>>>>>>>>> corecmd_list_bin(system_dbusd_t) >>>>>>>>>>> corecmd_read_bin_pipes(system_dbusd_t) >>>>>>>>>>> corecmd_read_bin_sockets(system_dbusd_t) >>>>>>>>>>> +# needed for system-tools-backends >>>>>>>>>>> +corecmd_exec_shell(system_dbusd_t) >>>>>>>>>>> >>>>>>>>>>> domain_use_interactive_fds(system_dbusd_t) >>>>>>>>>>> domain_read_all_domains_state(system_dbusd_t) >>>>>>>>>>> >>>>>>>>>>> +files_search_default(system_dbusd_t) >>>>>>>>>> >>>>>>>>>> There should not be able default_t type directories. Thus this shouldnt >>>>>>>>>> be allowed >>>>>>>>> >>>>>>>>> Apparently, I am no longer able to find the relative log. Best thing to >>>>>>>>> do in this case is to remove and test again. >>>>>>>>> >>>>>>>>>>> +files_read_default_files(system_dbusd_t) >>>>>>>>>> >>>>>>>>>> there should not be any default_t type files. Thus this shouldnt be allowed >>>>>>>>> >>>>>>>>> Same as above. Hopefully, we'll be able to get rid of that... >>>>>>>>> >>>>>>>>>>> files_read_etc_files(system_dbusd_t) >>>>>>>>>>> files_list_home(system_dbusd_t) >>>>>>>>>>> -files_read_usr_files(system_dbusd_t) >>>>>>>>>>> +files_exec_bin_files(system_dbusd_t) >>>>>>>>>> >>>>>>>>>> Which bin_t files is it executing? >>>>>>>>> >>>>>>>>> I think dbus-daemon-launch-helper is executing polkitd which is labelled >>>>>>>>> bin_t: >>>>>>>>> >>>>>>>>> type=AVC msg=audit(1294683706.729:33): avc: denied >>>>>>>>> { execute_no_trans } for pid=2718 comm="dbus-daemon-lau" >>>>>>>>> path="/usr/libexec/polkit-1/polkitd" dev=dm-1 ino=396675 >>>>>>>>> scontext=system_u:system_r:system_dbusd_t:s0-s0:c0.c1023 >>>>>>>>> tcontext=system_u:object_r:bin_t:s0 tclass=file >>>>>>>>> >>>>>>>> >>>>>>>> /usr/libexec/polkit-1/polkitd is labelled policykit_exec_t here. Then >>>>>>>> one should decide whether to allow system_dbusd_t to run it in the >>>>>>>> system_dbusd_t domain or to allow it to domain transition to policykit_t >>>>>>> >>>>>>> Yes, that was completely mistaken. Polkitd has now been labeled >>>>>>> correctly and all those weird permissions have been removed from the >>>>>>> dbus module. >>>>>>> >>>>>>> However, I had to create an interface policykit_can_execute() and a call >>>>>>> to it from dbus.te so that dbus can still execute polkitd. >>>>>>> >>>>>>>> This depends on what dbus is doing with policykit >>>>>>> >>>>>>> I think D-Bus is starting polkitd. If that doesn't happen, it would not >>>>>>> be possible to log onto the graphical interface. >>>>>>> polkitd runs in the system_dbusd_t domain. What does refpolicy expect in >>>>>>> this regard from the generic system it targets ? >>>>>>> >>>>>> >>>>>> I guess you need to add this to policykit module: >>>>>> >>>>>> dbus_system_domain(policykit_t, policykit_exec_t) >>>>> >>>>> I am now going to test what you propose as an alternative to using a >>>>> policykit_can_execute() interface. >>>>> >>>>>>>>>>> +files_exec_usr_files(system_dbusd_t) >>>>>>>>>> >>>>>>>>>> Which usr_t files is it executing? >>>>>>>>> >>>>>>>>> It's needed to execute a perl script from system-tools-backends (version >>>>>>>>> 2.10.1) which is located at: >>>>>>>>> >>>>>>>>> /usr/share/system-tools-backends-2.0/scripts/SystemToolsBackends.pl >>>>>>>>> >>>>>>>> >>>>>>>> This could be labelled bin_t. Maybe even write policy for it if >>>>>>>> applicable (probably a good idea so that we do not have to allow >>>>>>>> system_dbusd_t to run bin_t files (corecmd_exec_bin) >>>>>>>> >>>>>>>> What package does this file belong to? >>>>>>> >>>>>>> It belongs to system-tools-backends (version 2.10.1), see above. >>>>>>> >>>>>>> Yes, I could write more policy, but I would first prefer to get this >>>>>>> committed, otherwise it's pointless and too much stuff at the same time >>>>>>> can be confusing and in turn this could lead to mistakes. >>>>>> >>>>>> Yes but if you write policy for this then we may not need to allow dbus >>>>>> access to execute generic bin files. >>>>>> >>>>>> Although eventually we will probably have to allow it that anyways >>>>> >>>>> Yes. The DBus module needs { read open execute } permissions for >>>>> executing python in the system_dbusd_t domain. And that is bin_t:file, >>>>> so there is little it can be done to get around this issue. > > What do you say about the latest issue mentioned above ? Apparently > execute_no_trans in not enough for dbus to execute python. It is also > requiring the execute permission. So I thought domain transition could > help. i do not think dbusd_system_t needs access to either execute bin_t files or shell_exec_t files. I think that issue may or may not be caused when you ran policy kit or system_tools in the dbusd_system_t domain. > But then the corecmd_bin_domtrans() interface mentions that "this is not > suggested". What does that comment mean exactly ? Isn't that still > better than allowing system_dbusd_t bin_t:file execute ? > > Regards, > > Guido > -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.16 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/ iEYEARECAAYFAk1B2KoACgkQMlxVo39jgT9siQCgsErYCcpB3aRwNxytZWBm85bd 0tUAnRl25OMqOu84uAPW2jzOKANh/THQ =OxjA -----END PGP SIGNATURE-----