From: guido@trentalancia.com (Guido Trentalancia) Date: Wed, 26 Jan 2011 18:28:01 +0100 Subject: [refpolicy] [PATCH/RFC 8/19]: patch set to update the git reference policy In-Reply-To: <4D3FD8B5.9030306@gmail.com> 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> Message-ID: <1296062881.3028.18.camel@tesla.lan> To: refpolicy@oss.tresys.com List-Id: refpolicy.oss.tresys.com 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. > >>> and this is the log: > >>> > >>> type=AVC msg=audit(1294879948.810:42): avc: denied { execute } for > >>> pid=2966 comm="dbus-daemon-lau" name="SystemToolsBackends.pl" dev=dm-1 > >>> ino=442334 scontext=system_u:system_r:system_dbusd_t:s0-s0:c0.c1023 > >>> tcontext=system_u:object_r:usr_t:s0 tclass=file > >>> > >>> for the moment I have just written a comment in the TE file. Otherwise, > >>> we should relabel the perl script. What do you suggest ? > >>> > >>>>> +files_read_var_lib_files(system_dbusd_t) > >>>>> +files_var_log_append(system_dbusd_t) > >>>> > >>>> Which log is it appending to? > >>> > >>> Can't find the logs. Again, I can remove and test again, so we might get > >>> a better insight. Will let you know shortly. > > > > In any case, I had re-invented the wheel with those files_*_var_log_* > > interfaces. They are already available in the logging module, so all of > > them have now disappeared. > > Still question remains, which log files is it appending? That is not showing up anymore since I had removed it. So at the moment I can't tell you anything more. There is something new in another module (devicekit): fs_getattr_xattr_fs permissions needed both in devicekit_{disk,power}_t. That was [9/19] for reference and I also wrote a short note in that thread. So, we have almost finished tidying up things. What's next ? Regards, Guido