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				[euid=] [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]
31			       [[^]MAY_EXEC]
32			fsmagic:= hex value
33			fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6)
34			uid:= decimal value
35			euid:= decimal value
36			fowner:=decimal value
37		lsm:  	are LSM specific
38		option:	appraise_type:= [imasig]
39
40		default policy:
41			# PROC_SUPER_MAGIC
42			dont_measure fsmagic=0x9fa0
43			dont_appraise fsmagic=0x9fa0
44			# SYSFS_MAGIC
45			dont_measure fsmagic=0x62656572
46			dont_appraise fsmagic=0x62656572
47			# DEBUGFS_MAGIC
48			dont_measure fsmagic=0x64626720
49			dont_appraise fsmagic=0x64626720
50			# TMPFS_MAGIC
51			dont_measure fsmagic=0x01021994
52			dont_appraise fsmagic=0x01021994
53			# RAMFS_MAGIC
54			dont_appraise fsmagic=0x858458f6
55			# DEVPTS_SUPER_MAGIC
56			dont_measure fsmagic=0x1cd1
57			dont_appraise fsmagic=0x1cd1
58			# BINFMTFS_MAGIC
59			dont_measure fsmagic=0x42494e4d
60			dont_appraise fsmagic=0x42494e4d
61			# SECURITYFS_MAGIC
62			dont_measure fsmagic=0x73636673
63			dont_appraise fsmagic=0x73636673
64			# SELINUX_MAGIC
65			dont_measure fsmagic=0xf97cff8c
66			dont_appraise fsmagic=0xf97cff8c
67			# CGROUP_SUPER_MAGIC
68			dont_measure fsmagic=0x27e0eb
69			dont_appraise fsmagic=0x27e0eb
70			# NSFS_MAGIC
71			dont_measure fsmagic=0x6e736673
72			dont_appraise fsmagic=0x6e736673
73
74			measure func=BPRM_CHECK
75			measure func=FILE_MMAP mask=MAY_EXEC
76			measure func=FILE_CHECK mask=MAY_READ uid=0
77			measure func=MODULE_CHECK
78			measure func=FIRMWARE_CHECK
79			appraise fowner=0
80
81		The default policy measures all executables in bprm_check,
82		all files mmapped executable in file_mmap, and all files
83		open for read by root in do_filp_open.  The default appraisal
84		policy appraises all files owned by root.
85
86		Examples of LSM specific definitions:
87
88		SELinux:
89			dont_measure obj_type=var_log_t
90			dont_appraise obj_type=var_log_t
91			dont_measure obj_type=auditd_log_t
92			dont_appraise obj_type=auditd_log_t
93			measure subj_user=system_u func=FILE_CHECK mask=MAY_READ
94			measure subj_role=system_r func=FILE_CHECK mask=MAY_READ
95
96		Smack:
97			measure subj_user=_ func=FILE_CHECK mask=MAY_READ
98