On 7/29/19 9:48 PM, Sugar, David wrote:
On 7/29/19 8:49 PM, Chris PeBenito wrote:
On 7/25/19 10:43 AM, Sugar, David wrote:
Signed-off-by: Dave Sugar <dsugar@xxxxxxxxxx>
---
policy/modules/services/tpm2_abrmd.fc | 3 ++
policy/modules/services/tpm2_abrmd.if | 58 +++++++++++++++++++++++++++
policy/modules/services/tpm2_abrmd.te | 29 ++++++++++++++
3 files changed, 90 insertions(+)
create mode 100644 policy/modules/services/tpm2_abrmd.fc
create mode 100644 policy/modules/services/tpm2_abrmd.if
create mode 100644 policy/modules/services/tpm2_abrmd.te
I think my only question is about the module name. Why not tpm2? I'm
not well versed on the Linux TPM stack, but isn't there other components
that potentially could need policy, like tss or totp?
I used this name because the only SELinux policy needed was for the
daemon 'tpm2-abrmd'. The processes that interact with the daemon to
actually use the tpm are using default bin_t label and don't seem to
need any additional permissions. In my case I'm using /bin/tpm2_* and
/bin/clevis.
I see a tss package but it is only adding libraries. I don't see a
package for totp. I'm working on RHEL7.6 so there could be additional
binaries on other distributions that will need labeling.
I'm happy to go either way here. I don't have a strong feeling if other
tpm2 related stuff should get grouped into a single module or if they
should be separate.
I'm pretty sure anything using a tpm2 will need to use abrmd to access
the TPM. I just don't have enough insight to know if those other
binaries will need labeling and policy.
If the decision is made to use tpm2.{fc,if,te} would any of the policy
change? I feel like the fc and te files are still correct. Interface
names might be changed slightly, but also might be OK as is.
I think we should go with just tpm.*. Renaming modules is painful for
backwards compat. The interface names would change, e.g.
tpm2_enabledisable_abrmd, otherwise it seems ok.
Dave
diff --git a/policy/modules/services/tpm2_abrmd.fc
b/policy/modules/services/tpm2_abrmd.fc
new file mode 100644
index 00000000..4ccf2f25
--- /dev/null
+++ b/policy/modules/services/tpm2_abrmd.fc
@@ -0,0 +1,3 @@
+/usr/sbin/tpm2-abrmd --
gen_context(system_u:object_r:tpm2_abrmd_exec_t,s0)
+
+/usr/lib/systemd/system/[^/]*tpm2-abrmd\.service --
gen_context(system_u:object_r:tpm2_abrmd_unit_t,s0)
diff --git a/policy/modules/services/tpm2_abrmd.if
b/policy/modules/services/tpm2_abrmd.if
new file mode 100644
index 00000000..dabb4a65
--- /dev/null
+++ b/policy/modules/services/tpm2_abrmd.if
@@ -0,0 +1,58 @@
+## <summary>TPM2 Access Broker and Resource Management daemon.</summary>
+
+########################################
+## <summary>
+## Allow specified domain to enable/disable tpm2-abrmd unit
+## </summary>
+## <param name="domain">
+## <summary>
+## Domain allowed access.
+## </summary>
+## </param>
+#
+interface(`tpm2_abrmd_enabledisable',`
+ gen_require(`
+ type tpm2_abrmd_unit_t;
+ class service { enable disable };
+ ')
+
+ allow $1 tpm2_abrmd_unit_t:service { enable disable };
+')
+
+########################################
+## <summary>
+## Allow specified domain to start/stop tpm2-abrmd unit
+## </summary>
+## <param name="domain">
+## <summary>
+## Domain allowed access.
+## </summary>
+## </param>
+#
+interface(`tpm2_abrmd_startstop',`
+ gen_require(`
+ type tpm2_abrmd_unit_t;
+ class service { start stop };
+ ')
+
+ allow $1 tpm2_abrmd_unit_t:service { start stop };
+')
+
+########################################
+## <summary>
+## Allow specified domain to get status of tpm2-abrmd unit
+## </summary>
+## <param name="domain">
+## <summary>
+## Domain allowed access.
+## </summary>
+## </param>
+#
+interface(`tpm2_abrmd_status',`
+ gen_require(`
+ type tpm2_abrmd_unit_t;
+ class service status;
+ ')
+
+ allow $1 tpm2_abrmd_unit_t:service status;
+')
diff --git a/policy/modules/services/tpm2_abrmd.te
b/policy/modules/services/tpm2_abrmd.te
new file mode 100644
index 00000000..8a8ba5f0
--- /dev/null
+++ b/policy/modules/services/tpm2_abrmd.te
@@ -0,0 +1,29 @@
+policy_module(tpm2_abrmd, 1.0.0)
+
+########################################
+#
+# Declarations
+#
+
+type tpm2_abrmd_t;
+type tpm2_abrmd_exec_t;
+init_daemon_domain(tpm2_abrmd_t, tpm2_abrmd_exec_t)
+
+type tpm2_abrmd_unit_t;
+init_unit_file(tpm2_abrmd_unit_t)
+
+########################################
+#
+# Local policy
+#
+
+allow tpm2_abrmd_t self:process signal;
+allow tpm2_abrmd_t self:unix_stream_socket create_socket_perms;
+
+dev_rw_tpm(tpm2_abrmd_t)
+
+kernel_read_crypto_sysctls(tpm2_abrmd_t)
+kernel_read_system_state(tpm2_abrmd_t)
+
+dbus_system_bus_client(tpm2_abrmd_t)
+dbus_connect_system_bus(tpm2_abrmd_t)
--
Chris PeBenito
