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
22			base:	[[func=] [mask=] [fsmagic=] [uid=] [fowner]]
23			lsm:	[[subj_user=] [subj_role=] [subj_type=]
24				 [obj_user=] [obj_role=] [obj_type=]]
25
26		base: 	func:= [BPRM_CHECK][FILE_MMAP][FILE_CHECK][MODULE_CHECK]
27			mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
28			fsmagic:= hex value
29			uid:= decimal value
30			fowner:=decimal value
31		lsm:  	are LSM specific
32
33		default policy:
34			# PROC_SUPER_MAGIC
35			dont_measure fsmagic=0x9fa0
36			dont_appraise fsmagic=0x9fa0
37			# SYSFS_MAGIC
38			dont_measure fsmagic=0x62656572
39			dont_appraise fsmagic=0x62656572
40			# DEBUGFS_MAGIC
41			dont_measure fsmagic=0x64626720
42			dont_appraise fsmagic=0x64626720
43			# TMPFS_MAGIC
44			dont_measure fsmagic=0x01021994
45			dont_appraise fsmagic=0x01021994
46			# RAMFS_MAGIC
47			dont_measure fsmagic=0x858458f6
48			dont_appraise fsmagic=0x858458f6
49			# SECURITYFS_MAGIC
50			dont_measure fsmagic=0x73636673
51			dont_appraise fsmagic=0x73636673
52
53			measure func=BPRM_CHECK
54			measure func=FILE_MMAP mask=MAY_EXEC
55			measure func=FILE_CHECK mask=MAY_READ uid=0
56			measure func=MODULE_CHECK uid=0
57			appraise fowner=0
58
59		The default policy measures all executables in bprm_check,
60		all files mmapped executable in file_mmap, and all files
61		open for read by root in do_filp_open.  The default appraisal
62		policy appraises all files owned by root.
63
64		Examples of LSM specific definitions:
65
66		SELinux:
67			# SELINUX_MAGIC
68			dont_measure fsmagic=0xf97cff8c
69			dont_appraise fsmagic=0xf97cff8c
70
71			dont_measure obj_type=var_log_t
72			dont_appraise obj_type=var_log_t
73			dont_measure obj_type=auditd_log_t
74			dont_appraise obj_type=auditd_log_t
75			measure subj_user=system_u func=FILE_CHECK mask=MAY_READ
76			measure subj_role=system_r func=FILE_CHECK mask=MAY_READ
77
78		Smack:
79			measure subj_user=_ func=FILE_CHECK mask=MAY_READ
80