IMA: Add TCB policy as an example for ima_measurements.sh

ima_policy=tcb specification taken from IMA docs [1], with updating
tmpfs policy to limit dont_measure to func=FILE_CHECK. This allows to do
extra measurements, e.g. kexec boot command line, see kernel commit

7eef7c8bac9a ("ima: limit the builtin 'tcb' dont_measure tmpfs policy rule")

[1] https://ima-doc.readthedocs.io/en/latest/ima-policy.html#ima-policy-tcb

Link: https://lore.kernel.org/ltp/[email protected]/
Reviewed-by: Mimi Zohar <[email protected]>
Signed-off-by: Petr Vorel <[email protected]>

Author: pevik

testcases/kernel/security/integrity/ima/datafiles/Makefile

@@ -1,5 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-or-later
-# Copyright (c) Linux Test Project, 2019-2020
+# Copyright (c) Linux Test Project, 2019-2025
 # Copyright (c) 2020 Microsoft Corporation
 # Copyright (C) 2009, Cisco Systems Inc.
 # Ngie Cooper, July 2009
@@ -8,6 +8,6 @@ top_srcdir	?= ../../../../../..
 
 include	$(top_srcdir)/include/mk/env_pre.mk
 
-SUBDIRS	:= ima_kexec ima_keys ima_policy ima_selinux
+SUBDIRS	:= ima_kexec ima_keys ima_measurements ima_policy ima_selinux
 
 include $(top_srcdir)/include/mk/generic_trunk_target.mk

testcases/kernel/security/integrity/ima/datafiles/ima_measurements/Makefile

@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (c) Linux Test Project, 2025
+
+top_srcdir	?= ../../../../../../..
+
+include	$(top_srcdir)/include/mk/env_pre.mk
+
+INSTALL_DIR		:= testcases/data/ima_measurements
+INSTALL_TARGETS	:= *.policy
+
+include $(top_srcdir)/include/mk/generic_leaf_target.mk

testcases/kernel/security/integrity/ima/datafiles/ima_measurements/tcb.policy

@@ -0,0 +1,20 @@
+dont_measure fsmagic=0x9fa0
+dont_measure fsmagic=0x62656572
+dont_measure fsmagic=0x64626720
+dont_measure fsmagic=0x1021994 func=FILE_CHECK
+dont_measure fsmagic=0x1cd1
+dont_measure fsmagic=0x42494e4d
+dont_measure fsmagic=0x73636673
+dont_measure fsmagic=0xf97cff8c
+dont_measure fsmagic=0x43415d53
+dont_measure fsmagic=0x27e0eb
+dont_measure fsmagic=0x63677270
+dont_measure fsmagic=0x6e736673
+dont_measure fsmagic=0xde5e81e4
+measure func=MMAP_CHECK mask=MAY_EXEC
+measure func=BPRM_CHECK mask=MAY_EXEC
+measure func=FILE_CHECK mask=^MAY_READ euid=0
+measure func=FILE_CHECK mask=^MAY_READ uid=0
+measure func=MODULE_CHECK
+measure func=FIRMWARE_CHECK
+measure func=POLICY_CHECK