* [refpolicy] [PATCH 1/2]: cpucontrol module updates (stricter policy for CPU microcode updates)
2012-08-29 13:04 ` Christopher J. PeBenito
@ 2012-08-29 15:37 ` Guido Trentalancia
2012-09-08 10:27 ` Guido Trentalancia
1 sibling, 0 replies; 5+ messages in thread
From: Guido Trentalancia @ 2012-08-29 15:37 UTC (permalink / raw)
To: refpolicy
On 29/08/2012 15:04, Christopher J. PeBenito wrote:
> On 08/24/12 10:02, Guido Trentalancia wrote:
>> cpucontrol module updates:
>> - introduce the file contexts according to the standard location
>> of the most common application named microcode_ctl
>> (http://www.urbanmyth.org/microcode);
>> - add file contexts for CPUs from two different vendors, taking
>> into consideration specific customization of the location
>> for one distribution;
>> - add file contexts and declarations for the init script;
>> - introduce the ability to update the CPU microcode as
>> tunable policy, as apparently such operation might
>> modify the original licensing conditions (under some or
>> all circumstances: "personal, non-commercial use only");
>> - create a new device type specifically for the CPU microcode
>> updating functionality and modify the cpucontrol module so
>> that such distinct new type is used for the microcode
>> updating operation, thus leaving an open door for further
>> modifications that distinguish different CPU-related
>> applications/utilities to create further isolation;
>> - modify the interface definitions so that the CPU microcode
>> update utility can only write and not read (unneeded) the
>> corresponding above mentioned device type.
>>
>> Signed-off-by: Guido Trentalancia <guido@trentalancia.com>
>> ---
>> policy/modules/contrib/cpucontrol.fc | 18 +++++++++-
>> policy/modules/contrib/cpucontrol.te | 16 ++++++++-
>> policy/modules/kernel/devices.fc | 3 +
>> policy/modules/kernel/devices.if | 62
>> +++++++++++++++++++++++++++++++----
>> policy/modules/kernel/devices.te | 8 +++-
>> 5 files changed, 96 insertions(+), 11 deletions(-)
>>
>> diff -pruN refpolicy-08082012/policy/modules/contrib/cpucontrol.fc
>> refpolicy-08082012-microcode/policy/modules/contrib/cpucontrol.fc
>> --- refpolicy-08082012/policy/modules/contrib/cpucontrol.fc 2011-09-09
>> 18:29:23.563610858 +0200
>> +++ refpolicy-08082012-microcode/policy/modules/contrib/cpucontrol.fc
>> 2012-08-09 01:13:59.615119168 +0200
>> @@ -1,7 +1,23 @@
>> +/etc/microcode\.dat -- gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/etc/microcode_amd\.bin --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/etc/firmware/microcode\.dat --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/etc/firmware/microcode_amd.bin --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>>
>> -/etc/firmware/.* -- gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/etc/rc\.d/init\.d/microcode --
>> gen_context(system_u:object_r:cpucontrol_initrc_exec_t,s0)
>>
>> +ifdef(`distro_redhat',`
>> +/lib/firmware/intel-ucode(/.*)?
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/lib/firmware/amd-ucode(/.*)?
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/lib/firmware/microcode\.dat --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/lib/firmware/microcode_amd\.bat --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +')
>
> I'm conflicted. I assume that the /etc/microcode and /etc/firmware locations are the default for this app, /lib/firmware seems more appropriate. I suspect this is not a redhat-specific location.
As far as I remember the /etc/firmware location was originally chosen by
one distribution (maybe Fedora, I can't remember exactly the details).
If that is removed, it might break compatibility with previous releases.
Latest location chosen by Fedora should probably be /lib/firmware with
the variants included in the ifdef distro block.
>> +/usr/sbin/microcode_ctl --
>> gen_context(system_u:object_r:cpucontrol_exec_t,s0)
>> +/usr/local/sbin/microcode_ctl --
>> gen_context(system_u:object_r:cpucontrol_exec_t,s0)
>
> The /usr/local label is not necessary, as it will be handled by the file context path substitutions.
I wasn't sure how to proceed, /usr/local/sbin is the original default
location chosen by the unedited application's Makefile...
As for the other vendor, the specific application should be called
"ucodeadm" and I've included that with the /usr/sbin prefix in the next
version of the patch that I am preparing.
>> +ifdef(`distro_redhat',`
>> /sbin/microcode_ctl -- gen_context(system_u:object_r:cpucontrol_exec_t,s0)
>> +')
>
> I also don't think this change is really necessary.
I don't know. It probably got there from some brief research carried out
on recent Fedora builds...
But, if it's unneeded, I'll remove it in the next version that I'll post
as soon as possible with the other required amendments.
>> /usr/sbin/cpufreqd -- gen_context(system_u:object_r:cpuspeed_exec_t,s0)
>> /usr/sbin/cpuspeed -- gen_context(system_u:object_r:cpuspeed_exec_t,s0)
>> diff -pruN refpolicy-08082012/policy/modules/contrib/cpucontrol.te
>> refpolicy-08082012-microcode/policy/modules/contrib/cpucontrol.te
>> --- refpolicy-08082012/policy/modules/contrib/cpucontrol.te 2011-09-09
>> 18:29:23.563610858 +0200
>> +++ refpolicy-08082012-microcode/policy/modules/contrib/cpucontrol.te
>> 2012-08-09 00:23:07.079532236 +0200
>> @@ -5,10 +5,21 @@ policy_module(cpucontrol, 1.3.0)
>> # Declarations
>> #
>>
>> +## <desc>
>> +## <p>
>> +## Allow cpucontrol to upload new microcode
>> +## to the CPU.
>> +## </p>
>> +## </desc>
>> +gen_tunable(cpucontrol_can_upload_cpu_microcode, false)
>> +
>> type cpucontrol_t;
>> type cpucontrol_exec_t;
>> init_system_domain(cpucontrol_t, cpucontrol_exec_t)
>>
>> +type cpucontrol_initrc_exec_t;
>> +init_script_file(cpucontrol_initrc_exec_t)
>> +
>> type cpucontrol_conf_t;
>> files_type(cpucontrol_conf_t)
>>
>> @@ -37,7 +48,6 @@ kernel_read_proc_symlinks(cpucontrol_t)
>> kernel_read_kernel_sysctls(cpucontrol_t)
>>
>> dev_read_sysfs(cpucontrol_t)
>> -dev_rw_cpu_microcode(cpucontrol_t)
>>
>> fs_search_auto_mountpoints(cpucontrol_t)
>>
>> @@ -54,6 +64,10 @@ logging_send_syslog_msg(cpucontrol_t)
>>
>> userdom_dontaudit_use_unpriv_user_fds(cpucontrol_t)
>>
>> +tunable_policy(`cpucontrol_can_upload_cpu_microcode',`
>> + dev_write_cpu_microcode(cpucontrol_t)
>> +')
>
> I don't understand why this is conditional, especially since you removed the read permission on /dev/microcode. The point of the app is to load microcode.
Conditional because not everyone might want that to happen. For example,
one issue might be the licensing one.
It shall add more configurability.
Best regards,
Guido
^ permalink raw reply [flat|nested] 5+ messages in thread
* [refpolicy] [PATCH 1/2]: cpucontrol module updates (stricter policy for CPU microcode updates)
2012-08-29 13:04 ` Christopher J. PeBenito
2012-08-29 15:37 ` Guido Trentalancia
@ 2012-09-08 10:27 ` Guido Trentalancia
2012-09-17 13:28 ` Christopher J. PeBenito
1 sibling, 1 reply; 5+ messages in thread
From: Guido Trentalancia @ 2012-09-08 10:27 UTC (permalink / raw)
To: refpolicy
Hello.
Here is a revised version (1/1) of the patch for the cpucontrol module.
On 29/08/2012 15:04, Christopher J. PeBenito wrote:
> On 08/24/12 10:02, Guido Trentalancia wrote:
>> cpucontrol module updates:
>> - introduce the file contexts according to the standard location
>> of the most common application named microcode_ctl
>> (http://www.urbanmyth.org/microcode);
Dropped as risky. Can be tackled at a later time or by
users/distributions individually.
>> - add file contexts for CPUs from two different vendors, taking
>> into consideration specific customization of the location
>> for one distribution;
Not taking anymore into consideration binary location customizations as
too risky. Only adding generic support for the most likely location of
the application provided by the other manufacturer.
>> - add file contexts and declarations for the init script;
>> - introduce the ability to update the CPU microcode as
>> tunable policy, as apparently such operation might
>> modify the original licensing conditions (under some or
>> all circumstances: "personal, non-commercial use only");
>> - create a new device type specifically for the CPU microcode
>> updating functionality and modify the cpucontrol module so
>> that such distinct new type is used for the microcode
>> updating operation, thus leaving an open door for further
>> modifications that distinguish different CPU-related
>> applications/utilities to create further isolation;
>> - modify the interface definitions so that the CPU microcode
>> update utility can only write and not read (unneeded) the
>> corresponding above mentioned device type.
>>
>> Signed-off-by: Guido Trentalancia <guido@trentalancia.com>
>> ---
>> policy/modules/contrib/cpucontrol.fc | 18 +++++++++-
>> policy/modules/contrib/cpucontrol.te | 16 ++++++++-
>> policy/modules/kernel/devices.fc | 3 +
>> policy/modules/kernel/devices.if | 62
>> +++++++++++++++++++++++++++++++----
>> policy/modules/kernel/devices.te | 8 +++-
>> 5 files changed, 96 insertions(+), 11 deletions(-)
>>
>> diff -pruN refpolicy-08082012/policy/modules/contrib/cpucontrol.fc
>> refpolicy-08082012-microcode/policy/modules/contrib/cpucontrol.fc
>> --- refpolicy-08082012/policy/modules/contrib/cpucontrol.fc 2011-09-09
>> 18:29:23.563610858 +0200
>> +++ refpolicy-08082012-microcode/policy/modules/contrib/cpucontrol.fc
>> 2012-08-09 01:13:59.615119168 +0200
>> @@ -1,7 +1,23 @@
>> +/etc/microcode\.dat -- gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/etc/microcode_amd\.bin --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/etc/firmware/microcode\.dat --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/etc/firmware/microcode_amd.bin --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>>
>> -/etc/firmware/.* -- gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/etc/rc\.d/init\.d/microcode --
>> gen_context(system_u:object_r:cpucontrol_initrc_exec_t,s0)
>>
>> +ifdef(`distro_redhat',`
>> +/lib/firmware/intel-ucode(/.*)?
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/lib/firmware/amd-ucode(/.*)?
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/lib/firmware/microcode\.dat --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +/lib/firmware/microcode_amd\.bat --
>> gen_context(system_u:object_r:cpucontrol_conf_t,s0)
>> +')
>
> I'm conflicted. I assume that the /etc/microcode and /etc/firmware locations are the default for this app, /lib/firmware seems more appropriate. I suspect this is not a redhat-specific location.
>
>> +/usr/sbin/microcode_ctl --
>> gen_context(system_u:object_r:cpucontrol_exec_t,s0)
>> +/usr/local/sbin/microcode_ctl --
>> gen_context(system_u:object_r:cpucontrol_exec_t,s0)
>
> The /usr/local label is not necessary, as it will be handled by the file context path substitutions.
>
>> +ifdef(`distro_redhat',`
>> /sbin/microcode_ctl -- gen_context(system_u:object_r:cpucontrol_exec_t,s0)
>> +')
>
> I also don't think this change is really necessary.
>
>> /usr/sbin/cpufreqd -- gen_context(system_u:object_r:cpuspeed_exec_t,s0)
>> /usr/sbin/cpuspeed -- gen_context(system_u:object_r:cpuspeed_exec_t,s0)
>> diff -pruN refpolicy-08082012/policy/modules/contrib/cpucontrol.te
>> refpolicy-08082012-microcode/policy/modules/contrib/cpucontrol.te
>> --- refpolicy-08082012/policy/modules/contrib/cpucontrol.te 2011-09-09
>> 18:29:23.563610858 +0200
>> +++ refpolicy-08082012-microcode/policy/modules/contrib/cpucontrol.te
>> 2012-08-09 00:23:07.079532236 +0200
>> @@ -5,10 +5,21 @@ policy_module(cpucontrol, 1.3.0)
>> # Declarations
>> #
>>
>> +## <desc>
>> +## <p>
>> +## Allow cpucontrol to upload new microcode
>> +## to the CPU.
>> +## </p>
>> +## </desc>
>> +gen_tunable(cpucontrol_can_upload_cpu_microcode, false)
>> +
>> type cpucontrol_t;
>> type cpucontrol_exec_t;
>> init_system_domain(cpucontrol_t, cpucontrol_exec_t)
>>
>> +type cpucontrol_initrc_exec_t;
>> +init_script_file(cpucontrol_initrc_exec_t)
>> +
>> type cpucontrol_conf_t;
>> files_type(cpucontrol_conf_t)
>>
>> @@ -37,7 +48,6 @@ kernel_read_proc_symlinks(cpucontrol_t)
>> kernel_read_kernel_sysctls(cpucontrol_t)
>>
>> dev_read_sysfs(cpucontrol_t)
>> -dev_rw_cpu_microcode(cpucontrol_t)
>>
>> fs_search_auto_mountpoints(cpucontrol_t)
>>
>> @@ -54,6 +64,10 @@ logging_send_syslog_msg(cpucontrol_t)
>>
>> userdom_dontaudit_use_unpriv_user_fds(cpucontrol_t)
>>
>> +tunable_policy(`cpucontrol_can_upload_cpu_microcode',`
>> + dev_write_cpu_microcode(cpucontrol_t)
>> +')
>
> I don't understand why this is conditional, especially since you removed the read permission on /dev/microcode. The point of the app is to load microcode.
diff -pruN
refpolicy-09082012-git-master/policy/modules/contrib/cpucontrol.fc
refpolicy-09082012-microcode-v3/policy/modules/contrib/cpucontrol.fc
--- refpolicy-09082012-git-master/policy/modules/contrib/cpucontrol.fc
Thu Aug 23 19:22:59 2012
+++
refpolicy-09082012-microcode-v3/policy/modules/contrib/cpucontrol.fc Sat
Sep 8 10:16:21 2012
@@ -1,7 +1,12 @@
-
/etc/firmware/.* -- gen_context(system_u:object_r:cpucontrol_conf_t,s0)
+/etc/rc\.d/init\.d/microcode --
gen_context(system_u:object_r:cpucontrol_conf_t,s0)
+
+# Intel(R) devices supporting application
/sbin/microcode_ctl -- gen_context(system_u:object_r:cpucontrol_exec_t,s0)
+
+# AMD(tm) devices application
+/sbin/ucodeadm -- gen_context(system_u:object_r:cpucontrol_exec_t,s0)
/usr/sbin/cpufreqd -- gen_context(system_u:object_r:cpuspeed_exec_t,s0)
/usr/sbin/cpuspeed -- gen_context(system_u:object_r:cpuspeed_exec_t,s0)
diff -pruN
refpolicy-09082012-git-master/policy/modules/contrib/cpucontrol.te
refpolicy-09082012-microcode-v3/policy/modules/contrib/cpucontrol.te
--- refpolicy-09082012-git-master/policy/modules/contrib/cpucontrol.te
Thu Aug 23 19:22:59 2012
+++
refpolicy-09082012-microcode-v3/policy/modules/contrib/cpucontrol.te Sat
Sep 8 10:10:55 2012
@@ -5,10 +5,21 @@ policy_module(cpucontrol, 1.3.0)
# Declarations
#
+## <desc>
+## <p>
+## Allow cpucontrol to upload new microcode
+## to the CPU.
+## </p>
+## </desc>
+gen_tunable(cpucontrol_can_upload_cpu_microcode, false)
+
type cpucontrol_t;
type cpucontrol_exec_t;
init_system_domain(cpucontrol_t, cpucontrol_exec_t)
+type cpucontrol_initrc_exec_t;
+init_script_file(cpucontrol_initrc_exec_t)
+
type cpucontrol_conf_t;
files_type(cpucontrol_conf_t)
@@ -37,7 +48,6 @@ kernel_read_proc_symlinks(cpucontrol_t)
kernel_read_kernel_sysctls(cpucontrol_t)
dev_read_sysfs(cpucontrol_t)
-dev_rw_cpu_microcode(cpucontrol_t)
fs_search_auto_mountpoints(cpucontrol_t)
@@ -53,6 +63,10 @@ init_use_script_ptys(cpucontrol_t)
logging_send_syslog_msg(cpucontrol_t)
userdom_dontaudit_use_unpriv_user_fds(cpucontrol_t)
+
+tunable_policy(`cpucontrol_can_upload_cpu_microcode',`
+ dev_write_cpu_microcode(cpucontrol_t)
+')
optional_policy(`
nscd_socket_use(cpucontrol_t)
diff -pruN
refpolicy-09082012-git-master/policy/modules/kernel/devices.fc
refpolicy-09082012-microcode-v3/policy/modules/kernel/devices.fc
--- refpolicy-09082012-git-master/policy/modules/kernel/devices.fc Thu
Sep 6 10:50:18 2012
+++ refpolicy-09082012-microcode-v3/policy/modules/kernel/devices.fc Sat
Sep 8 10:10:55 2012
@@ -65,7 +65,7 @@
/dev/mergemem -c
gen_context(system_u:object_r:memory_device_t,mls_systemhigh)
/dev/mga_vid.* -c gen_context(system_u:object_r:xserver_misc_device_t,s0)
/dev/mice -c gen_context(system_u:object_r:mouse_device_t,s0)
-/dev/microcode -c gen_context(system_u:object_r:cpu_device_t,s0)
+/dev/microcode -c gen_context(system_u:object_r:cpu_microcode_device_t,s0)
/dev/midi.* -c gen_context(system_u:object_r:sound_device_t,s0)
/dev/misc/dlm.* -c gen_context(system_u:object_r:dlm_control_device_t,s0)
/dev/mixer.* -c gen_context(system_u:object_r:sound_device_t,s0)
@@ -139,6 +139,7 @@ ifdef(`distro_suse', `
/dev/cpu_dma_latency -c
gen_context(system_u:object_r:netcontrol_device_t,s0)
/dev/cpu.* -c gen_context(system_u:object_r:cpu_device_t,s0)
+/dev/cpu/microcode -c
gen_context(system_u:object_r:cpu_microcode_device_t,s0)
/dev/cpu/mtrr -c gen_context(system_u:object_r:mtrr_device_t,s0)
/dev/biometric/sensor.* -c
gen_context(system_u:object_r:event_device_t,s0)
diff -pruN
refpolicy-09082012-git-master/policy/modules/kernel/devices.if
refpolicy-09082012-microcode-v3/policy/modules/kernel/devices.if
--- refpolicy-09082012-git-master/policy/modules/kernel/devices.if Thu
Aug 23 19:16:55 2012
+++ refpolicy-09082012-microcode-v3/policy/modules/kernel/devices.if Sat
Sep 8 10:10:55 2012
@@ -1664,7 +1664,7 @@ interface(`dev_filetrans_cardmgr',`
########################################
## <summary>
## Get the attributes of the CPU
-## microcode and id interfaces.
+## id interfaces.
## </summary>
## <param name="domain">
## <summary>
@@ -1682,8 +1682,27 @@ interface(`dev_getattr_cpu_dev',`
########################################
## <summary>
+## Get the attributes of the CPU
+## microcode interface.
+## </summary>
+## <param name="domain">
+## <summary>
+## Domain allowed access.
+## </summary>
+## </param>
+#
+interface(`dev_getattr_cpu_microcode_dev',`
+ gen_require(`
+ type device_t, cpu_microcode_device_t;
+ ')
+
+ getattr_chr_files_pattern($1, device_t, cpu_microcode_device_t)
+')
+
+########################################
+## <summary>
## Set the attributes of the CPU
-## microcode and id interfaces.
+## id interfaces.
## </summary>
## <param name="domain">
## <summary>
@@ -1701,6 +1720,25 @@ interface(`dev_setattr_cpu_dev',`
########################################
## <summary>
+## Set the attributes of the CPU
+## id interfaces.
+## </summary>
+## <param name="domain">
+## <summary>
+## Domain allowed access.
+## </summary>
+## </param>
+#
+interface(`dev_setattr_cpu_microcode_dev',`
+ gen_require(`
+ type device_t, cpu_microcode_device_t;
+ ')
+
+ setattr_chr_files_pattern($1, device_t, cpu_microcode_device_t)
+')
+
+########################################
+## <summary>
## Read the CPU identity.
## </summary>
## <param name="domain">
@@ -1719,21 +1757,31 @@ interface(`dev_read_cpuid',`
########################################
## <summary>
-## Read and write the the CPU microcode device. This
-## is required to load CPU microcode.
+## Write the CPU microcode device. This
+## is required to upload the CPU microcode.
## </summary>
+## <desc>
+## <p>
+## Write the CPU microcode device.
+## This interface can be used to upload the
+## CPU microcode.
+## </p>
+## <p>
+## There might be license modifications.
+## </p>
+## </desc>
## <param name="domain">
## <summary>
## Domain allowed access.
## </summary>
## </param>
#
-interface(`dev_rw_cpu_microcode',`
+interface(`dev_write_cpu_microcode',`
gen_require(`
- type device_t, cpu_device_t;
+ type device_t, cpu_microcode_device_t;
')
- rw_chr_files_pattern($1, device_t, cpu_device_t)
+ write_chr_files_pattern($1, device_t, cpu_microcode_device_t)
')
########################################
diff -pruN
refpolicy-09082012-git-master/policy/modules/kernel/devices.te
refpolicy-09082012-microcode-v3/policy/modules/kernel/devices.te
--- refpolicy-09082012-git-master/policy/modules/kernel/devices.te Thu
Sep 6 10:50:18 2012
+++ refpolicy-09082012-microcode-v3/policy/modules/kernel/devices.te Sat
Sep 8 10:10:55 2012
@@ -51,10 +51,16 @@ type clock_device_t;
dev_node(clock_device_t)
#
-# cpu control devices /dev/cpu/0/*
+# cpu control devices /dev/cpu/?/*
#
type cpu_device_t;
dev_node(cpu_device_t)
+
+#
+# cpu microcode device /dev/cpu/microcode
+#
+type cpu_microcode_device_t;
+dev_node(cpu_microcode_device_t)
#
# Type for /dev/crash
^ permalink raw reply [flat|nested] 5+ messages in thread