1What:		security/ima/policy
2Date:		May 2008
3Contact:	Mimi Zohar <zohar@us.ibm.com>
4Description:
5		The Trusted Computing Group(TCG) runtime Integrity
6		Measurement Architecture(IMA) maintains a list of hash
7		values of executables and other sensitive system files
8		loaded into the run-time of this system.  At runtime,
9		the policy can be constrained based on LSM specific data.
10		Policies are loaded into the securityfs file ima/policy
11		by opening the file, writing the rules one at a time and
12		then closing the file.  The new policy takes effect after
13		the file ima/policy is closed.
14
15		IMA appraisal, if configured, uses these file measurements
16		for local measurement appraisal.
17
18		rule format: action [condition ...]
19
20		action: measure | dont_measure | appraise | dont_appraise | audit
21		condition:= base | lsm  [option]
22			base:	[[func=] [mask=] [fsmagic=] [fsuuid=] [uid=]
23				 [fowner]]
24			lsm:	[[subj_user=] [subj_role=] [subj_type=]
25				 [obj_user=] [obj_role=] [obj_type=]]
26			option:	[[appraise_type=]] [permit_directio]
27
28		base: 	func:= [BPRM_CHECK][MMAP_CHECK][FILE_CHECK][MODULE_CHECK]
29				[FIRMWARE_CHECK]
30			mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
31			fsmagic:= hex value
32			fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6)
33			uid:= decimal value
34			fowner:=decimal value
35		lsm:  	are LSM specific
36		option:	appraise_type:= [imasig]
37
38		default policy:
39			# PROC_SUPER_MAGIC
40			dont_measure fsmagic=0x9fa0
41			dont_appraise fsmagic=0x9fa0
42			# SYSFS_MAGIC
43			dont_measure fsmagic=0x62656572
44			dont_appraise fsmagic=0x62656572
45			# DEBUGFS_MAGIC
46			dont_measure fsmagic=0x64626720
47			dont_appraise fsmagic=0x64626720
48			# TMPFS_MAGIC
49			dont_measure fsmagic=0x01021994
50			dont_appraise fsmagic=0x01021994
51			# RAMFS_MAGIC
52			dont_measure fsmagic=0x858458f6
53			dont_appraise fsmagic=0x858458f6
54			# SECURITYFS_MAGIC
55			dont_measure fsmagic=0x73636673
56			dont_appraise fsmagic=0x73636673
57
58			measure func=BPRM_CHECK
59			measure func=FILE_MMAP mask=MAY_EXEC
60			measure func=FILE_CHECK mask=MAY_READ uid=0
61			measure func=MODULE_CHECK
62			measure func=FIRMWARE_CHECK
63			appraise fowner=0
64
65		The default policy measures all executables in bprm_check,
66		all files mmapped executable in file_mmap, and all files
67		open for read by root in do_filp_open.  The default appraisal
68		policy appraises all files owned by root.
69
70		Examples of LSM specific definitions:
71
72		SELinux:
73			# SELINUX_MAGIC
74			dont_measure fsmagic=0xf97cff8c
75			dont_appraise fsmagic=0xf97cff8c
76
77			dont_measure obj_type=var_log_t
78			dont_appraise obj_type=var_log_t
79			dont_measure obj_type=auditd_log_t
80			dont_appraise obj_type=auditd_log_t
81			measure subj_user=system_u func=FILE_CHECK mask=MAY_READ
82			measure subj_role=system_r func=FILE_CHECK mask=MAY_READ
83
84		Smack:
85			measure subj_user=_ func=FILE_CHECK mask=MAY_READ
86