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				[KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
31			mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
32			       [[^]MAY_EXEC]
33			fsmagic:= hex value
34			fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6)
35			uid:= decimal value
36			euid:= decimal value
37			fowner:=decimal value
38		lsm:  	are LSM specific
39		option:	appraise_type:= [imasig]
40
41		default policy:
42			# PROC_SUPER_MAGIC
43			dont_measure fsmagic=0x9fa0
44			dont_appraise fsmagic=0x9fa0
45			# SYSFS_MAGIC
46			dont_measure fsmagic=0x62656572
47			dont_appraise fsmagic=0x62656572
48			# DEBUGFS_MAGIC
49			dont_measure fsmagic=0x64626720
50			dont_appraise fsmagic=0x64626720
51			# TMPFS_MAGIC
52			dont_measure fsmagic=0x01021994
53			dont_appraise fsmagic=0x01021994
54			# RAMFS_MAGIC
55			dont_appraise fsmagic=0x858458f6
56			# DEVPTS_SUPER_MAGIC
57			dont_measure fsmagic=0x1cd1
58			dont_appraise fsmagic=0x1cd1
59			# BINFMTFS_MAGIC
60			dont_measure fsmagic=0x42494e4d
61			dont_appraise fsmagic=0x42494e4d
62			# SECURITYFS_MAGIC
63			dont_measure fsmagic=0x73636673
64			dont_appraise fsmagic=0x73636673
65			# SELINUX_MAGIC
66			dont_measure fsmagic=0xf97cff8c
67			dont_appraise fsmagic=0xf97cff8c
68			# CGROUP_SUPER_MAGIC
69			dont_measure fsmagic=0x27e0eb
70			dont_appraise fsmagic=0x27e0eb
71			# NSFS_MAGIC
72			dont_measure fsmagic=0x6e736673
73			dont_appraise fsmagic=0x6e736673
74
75			measure func=BPRM_CHECK
76			measure func=FILE_MMAP mask=MAY_EXEC
77			measure func=FILE_CHECK mask=MAY_READ uid=0
78			measure func=MODULE_CHECK
79			measure func=FIRMWARE_CHECK
80			appraise fowner=0
81
82		The default policy measures all executables in bprm_check,
83		all files mmapped executable in file_mmap, and all files
84		open for read by root in do_filp_open.  The default appraisal
85		policy appraises all files owned by root.
86
87		Examples of LSM specific definitions:
88
89		SELinux:
90			dont_measure obj_type=var_log_t
91			dont_appraise obj_type=var_log_t
92			dont_measure obj_type=auditd_log_t
93			dont_appraise obj_type=auditd_log_t
94			measure subj_user=system_u func=FILE_CHECK mask=MAY_READ
95			measure subj_role=system_r func=FILE_CHECK mask=MAY_READ
96
97		Smack:
98			measure subj_user=_ func=FILE_CHECK mask=MAY_READ
99