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			mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
30			fsmagic:= hex value
31			fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6)
32			uid:= decimal value
33			fowner:=decimal value
34		lsm:  	are LSM specific
35		option:	appraise_type:= [imasig]
36
37		default policy:
38			# PROC_SUPER_MAGIC
39			dont_measure fsmagic=0x9fa0
40			dont_appraise fsmagic=0x9fa0
41			# SYSFS_MAGIC
42			dont_measure fsmagic=0x62656572
43			dont_appraise fsmagic=0x62656572
44			# DEBUGFS_MAGIC
45			dont_measure fsmagic=0x64626720
46			dont_appraise fsmagic=0x64626720
47			# TMPFS_MAGIC
48			dont_measure fsmagic=0x01021994
49			dont_appraise fsmagic=0x01021994
50			# RAMFS_MAGIC
51			dont_measure fsmagic=0x858458f6
52			dont_appraise fsmagic=0x858458f6
53			# SECURITYFS_MAGIC
54			dont_measure fsmagic=0x73636673
55			dont_appraise fsmagic=0x73636673
56
57			measure func=BPRM_CHECK
58			measure func=FILE_MMAP mask=MAY_EXEC
59			measure func=FILE_CHECK mask=MAY_READ uid=0
60			measure func=MODULE_CHECK uid=0
61			appraise fowner=0
62
63		The default policy measures all executables in bprm_check,
64		all files mmapped executable in file_mmap, and all files
65		open for read by root in do_filp_open.  The default appraisal
66		policy appraises all files owned by root.
67
68		Examples of LSM specific definitions:
69
70		SELinux:
71			# SELINUX_MAGIC
72			dont_measure fsmagic=0xf97cff8c
73			dont_appraise fsmagic=0xf97cff8c
74
75			dont_measure obj_type=var_log_t
76			dont_appraise obj_type=var_log_t
77			dont_measure obj_type=auditd_log_t
78			dont_appraise obj_type=auditd_log_t
79			measure subj_user=system_u func=FILE_CHECK mask=MAY_READ
80			measure subj_role=system_r func=FILE_CHECK mask=MAY_READ
81
82		Smack:
83			measure subj_user=_ func=FILE_CHECK mask=MAY_READ
84