[mirror_ubuntu-jammy-kernel.git] / Documentation / ABI / testing / ima_policy

What:		security/ima/policy
Date:		May 2008
Contact:	Mimi Zohar <zohar@us.ibm.com>
Description:
		The Trusted Computing Group(TCG) runtime Integrity
		Measurement Architecture(IMA) maintains a list of hash
		values of executables and other sensitive system files
		loaded into the run-time of this system.  At runtime,
		the policy can be constrained based on LSM specific data.
		Policies are loaded into the securityfs file ima/policy
		by opening the file, writing the rules one at a time and
		then closing the file.  The new policy takes effect after
		the file ima/policy is closed.

		IMA appraisal, if configured, uses these file measurements
		for local measurement appraisal.

		::

		  rule format: action [condition ...]

		  action: measure | dont_measure | appraise | dont_appraise |
			  audit | hash | dont_hash
		  condition:= base | lsm  [option]
			base:	[[func=] [mask=] [fsmagic=] [fsuuid=] [uid=]
				[euid=] [fowner=] [fsname=]]
			lsm:	[[subj_user=] [subj_role=] [subj_type=]
				 [obj_user=] [obj_role=] [obj_type=]]
			option:	[[appraise_type=]] [template=] [permit_directio]
				[appraise_flag=] [keyrings=]
		  base:
			func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK]
			        [FIRMWARE_CHECK]
				[KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
				[KEXEC_CMDLINE] [KEY_CHECK]
			mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
			       [[^]MAY_EXEC]
			fsmagic:= hex value
			fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6)
			uid:= decimal value
			euid:= decimal value
			fowner:= decimal value
		  lsm:  are LSM specific
		  option:
			appraise_type:= [imasig] [imasig|modsig]
			appraise_flag:= [check_blacklist]
			Currently, blacklist check is only for files signed with appended
			signature.
			keyrings:= list of keyrings
			(eg, .builtin_trusted_keys|.ima). Only valid
			when action is "measure" and func is KEY_CHECK.
			template:= name of a defined IMA template type
			(eg, ima-ng). Only valid when action is "measure".
			pcr:= decimal value

		  default policy:
			# PROC_SUPER_MAGIC
			dont_measure fsmagic=0x9fa0
			dont_appraise fsmagic=0x9fa0
			# SYSFS_MAGIC
			dont_measure fsmagic=0x62656572
			dont_appraise fsmagic=0x62656572
			# DEBUGFS_MAGIC
			dont_measure fsmagic=0x64626720
			dont_appraise fsmagic=0x64626720
			# TMPFS_MAGIC
			dont_measure fsmagic=0x01021994
			dont_appraise fsmagic=0x01021994
			# RAMFS_MAGIC
			dont_appraise fsmagic=0x858458f6
			# DEVPTS_SUPER_MAGIC
			dont_measure fsmagic=0x1cd1
			dont_appraise fsmagic=0x1cd1
			# BINFMTFS_MAGIC
			dont_measure fsmagic=0x42494e4d
			dont_appraise fsmagic=0x42494e4d
			# SECURITYFS_MAGIC
			dont_measure fsmagic=0x73636673
			dont_appraise fsmagic=0x73636673
			# SELINUX_MAGIC
			dont_measure fsmagic=0xf97cff8c
			dont_appraise fsmagic=0xf97cff8c
			# CGROUP_SUPER_MAGIC
			dont_measure fsmagic=0x27e0eb
			dont_appraise fsmagic=0x27e0eb
			# NSFS_MAGIC
			dont_measure fsmagic=0x6e736673
			dont_appraise fsmagic=0x6e736673

			measure func=BPRM_CHECK
			measure func=FILE_MMAP mask=MAY_EXEC
			measure func=FILE_CHECK mask=MAY_READ uid=0
			measure func=MODULE_CHECK
			measure func=FIRMWARE_CHECK
			appraise fowner=0

		The default policy measures all executables in bprm_check,
		all files mmapped executable in file_mmap, and all files
		open for read by root in do_filp_open.  The default appraisal
		policy appraises all files owned by root.

		Examples of LSM specific definitions:

		SELinux::

			dont_measure obj_type=var_log_t
			dont_appraise obj_type=var_log_t
			dont_measure obj_type=auditd_log_t
			dont_appraise obj_type=auditd_log_t
			measure subj_user=system_u func=FILE_CHECK mask=MAY_READ
			measure subj_role=system_r func=FILE_CHECK mask=MAY_READ

		Smack::

			measure subj_user=_ func=FILE_CHECK mask=MAY_READ

		Example of measure rules using alternate PCRs::

			measure func=KEXEC_KERNEL_CHECK pcr=4
			measure func=KEXEC_INITRAMFS_CHECK pcr=5

		Example of appraise rule allowing modsig appended signatures:

			appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig|modsig

		Example of measure rule using KEY_CHECK to measure all keys:

			measure func=KEY_CHECK

		Example of measure rule using KEY_CHECK to only measure
		keys added to .builtin_trusted_keys or .ima keyring:

			measure func=KEY_CHECK keyrings=.builtin_trusted_keys|.ima
Commit	Line	Data
4af4662f MZ	1	What: security/ima/policy
	2	Date: May 2008
	3	Contact: Mimi Zohar <zohar@us.ibm.com>
	4	Description:
	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
07f6a794 MZ	15	IMA appraisal, if configured, uses these file measurements
	16	for local measurement appraisal.
	17
34433332	18	::
4af4662f	19
34433332 MCC	20	rule format: action [condition ...]
	21
	22	action: measure \| dont_measure \| appraise \| dont_appraise \|
	23	audit \| hash \| dont_hash
	24	condition:= base \| lsm [option]
85865c1f	25	base: [[func=] [mask=] [fsmagic=] [fsuuid=] [uid=]
f1b08bbc	26	[euid=] [fowner=] [fsname=]]
4af4662f MZ	27	lsm: [[subj_user=] [subj_role=] [subj_type=]
4af4662f MZ	28	[obj_user=] [obj_role=] [obj_type=]]
19453ce0	29	option: [[appraise_type=]] [template=] [permit_directio]
e9085e0a	30	[appraise_flag=] [keyrings=]
34433332	31	base:
c418eed8	32	func:= [BPRM_CHECK][MMAP_CHECK][CREDS_CHECK][FILE_CHECK][MODULE_CHECK]
34433332	33	[FIRMWARE_CHECK]
d9ddf077	34	[KEXEC_KERNEL_CHECK] [KEXEC_INITRAMFS_CHECK]
5808611c	35	[KEXEC_CMDLINE] [KEY_CHECK]
4351c294 MZ	36	mask:= [[^]MAY_READ] [[^]MAY_WRITE] [[^]MAY_APPEND]
4351c294 MZ	37	[[^]MAY_EXEC]
4af4662f	38	fsmagic:= hex value
85865c1f	39	fsuuid:= file system UUID (e.g 8bcbe394-4f13-4144-be8e-5aa9ea2ce2f6)
4af4662f	40	uid:= decimal value
139069ef	41	euid:= decimal value
fc26bd50	42	fowner:= decimal value
34433332 MCC	43	lsm: are LSM specific
	44	option:
	45	appraise_type:= [imasig] [imasig\|modsig]
273df864 NJ	46	appraise_flag:= [check_blacklist]
	47	Currently, blacklist check is only for files signed with appended
	48	signature.
e9085e0a LR	49	keyrings:= list of keyrings
	50	(eg, .builtin_trusted_keys\|.ima). Only valid
	51	when action is "measure" and func is KEY_CHECK.
19453ce0 MG	52	template:= name of a defined IMA template type
19453ce0 MG	53	(eg, ima-ng). Only valid when action is "measure".
fc26bd50	54	pcr:= decimal value
4af4662f	55
34433332	56	default policy:
4af4662f MZ	57	# PROC_SUPER_MAGIC
4af4662f MZ	58	dont_measure fsmagic=0x9fa0
07f6a794	59	dont_appraise fsmagic=0x9fa0
4af4662f MZ	60	# SYSFS_MAGIC
4af4662f MZ	61	dont_measure fsmagic=0x62656572
07f6a794	62	dont_appraise fsmagic=0x62656572
4af4662f MZ	63	# DEBUGFS_MAGIC
4af4662f MZ	64	dont_measure fsmagic=0x64626720
07f6a794	65	dont_appraise fsmagic=0x64626720
4af4662f MZ	66	# TMPFS_MAGIC
4af4662f MZ	67	dont_measure fsmagic=0x01021994
07f6a794 MZ	68	dont_appraise fsmagic=0x01021994
07f6a794 MZ	69	# RAMFS_MAGIC
07f6a794	70	dont_appraise fsmagic=0x858458f6
6438de9f RS	71	# DEVPTS_SUPER_MAGIC
	72	dont_measure fsmagic=0x1cd1
	73	dont_appraise fsmagic=0x1cd1
	74	# BINFMTFS_MAGIC
	75	dont_measure fsmagic=0x42494e4d
	76	dont_appraise fsmagic=0x42494e4d
4af4662f MZ	77	# SECURITYFS_MAGIC
4af4662f MZ	78	dont_measure fsmagic=0x73636673
07f6a794	79	dont_appraise fsmagic=0x73636673
6438de9f RS	80	# SELINUX_MAGIC
	81	dont_measure fsmagic=0xf97cff8c
	82	dont_appraise fsmagic=0xf97cff8c
	83	# CGROUP_SUPER_MAGIC
	84	dont_measure fsmagic=0x27e0eb
	85	dont_appraise fsmagic=0x27e0eb
cd025f7f MZ	86	# NSFS_MAGIC
	87	dont_measure fsmagic=0x6e736673
	88	dont_appraise fsmagic=0x6e736673
4af4662f MZ	89
	90	measure func=BPRM_CHECK
	91	measure func=FILE_MMAP mask=MAY_EXEC
1e93d005	92	measure func=FILE_CHECK mask=MAY_READ uid=0
5a9196d7 MZ	93	measure func=MODULE_CHECK
5a9196d7 MZ	94	measure func=FIRMWARE_CHECK
07f6a794	95	appraise fowner=0
4af4662f MZ	96
	97	The default policy measures all executables in bprm_check,
	98	all files mmapped executable in file_mmap, and all files
07f6a794 MZ	99	open for read by root in do_filp_open. The default appraisal
07f6a794 MZ	100	policy appraises all files owned by root.
4af4662f MZ	101
	102	Examples of LSM specific definitions:
	103
34433332 MCC	104	SELinux::
34433332 MCC	105
4af4662f	106	dont_measure obj_type=var_log_t
07f6a794	107	dont_appraise obj_type=var_log_t
4af4662f	108	dont_measure obj_type=auditd_log_t
07f6a794	109	dont_appraise obj_type=auditd_log_t
1e93d005 MZ	110	measure subj_user=system_u func=FILE_CHECK mask=MAY_READ
1e93d005 MZ	111	measure subj_role=system_r func=FILE_CHECK mask=MAY_READ
4af4662f	112
34433332 MCC	113	Smack::
34433332 MCC	114
1e93d005	115	measure subj_user=_ func=FILE_CHECK mask=MAY_READ
fc26bd50	116
34433332	117	Example of measure rules using alternate PCRs::
fc26bd50 ER	118
	119	measure func=KEXEC_KERNEL_CHECK pcr=4
	120	measure func=KEXEC_INITRAMFS_CHECK pcr=5
9044d627 TJB	121
	122	Example of appraise rule allowing modsig appended signatures:
	123
	124	appraise func=KEXEC_KERNEL_CHECK appraise_type=imasig\|modsig
5808611c LR	125
	126	Example of measure rule using KEY_CHECK to measure all keys:
	127
	128	measure func=KEY_CHECK
e9085e0a LR	129
	130	Example of measure rule using KEY_CHECK to only measure
	131	keys added to .builtin_trusted_keys or .ima keyring:
	132
	133	measure func=KEY_CHECK keyrings=.builtin_trusted_keys\|.ima