[linux-2.6-block.git] / security / keys / Kconfig

# SPDX-License-Identifier: GPL-2.0-only
#
# Key management configuration
#

config KEYS
	bool "Enable access key retention support"
	select ASSOCIATIVE_ARRAY
	help
	  This option provides support for retaining authentication tokens and
	  access keys in the kernel.

	  It also includes provision of methods by which such keys might be
	  associated with a process so that network filesystems, encryption
	  support and the like can find them.

	  Furthermore, a special type of key is available that acts as keyring:
	  a searchable sequence of keys. Each process is equipped with access
	  to five standard keyrings: UID-specific, GID-specific, session,
	  process and thread.

	  If you are unsure as to whether this is required, answer N.

config KEYS_REQUEST_CACHE
	bool "Enable temporary caching of the last request_key() result"
	depends on KEYS
	help
	  This option causes the result of the last successful request_key()
	  call that didn't upcall to the kernel to be cached temporarily in the
	  task_struct.  The cache is cleared by exit and just prior to the
	  resumption of userspace.

	  This allows the key used for multiple step processes where each step
	  wants to request a key that is likely the same as the one requested
	  by the last step to save on the searching.

	  An example of such a process is a pathwalk through a network
	  filesystem in which each method needs to request an authentication
	  key.  Pathwalk will call multiple methods for each dentry traversed
	  (permission, d_revalidate, lookup, getxattr, getacl, ...).

config PERSISTENT_KEYRINGS
	bool "Enable register of persistent per-UID keyrings"
	depends on KEYS
	help
	  This option provides a register of persistent per-UID keyrings,
	  primarily aimed at Kerberos key storage.  The keyrings are persistent
	  in the sense that they stay around after all processes of that UID
	  have exited, not that they survive the machine being rebooted.

	  A particular keyring may be accessed by either the user whose keyring
	  it is or by a process with administrative privileges.  The active
	  LSMs gets to rule on which admin-level processes get to access the
	  cache.

	  Keyrings are created and added into the register upon demand and get
	  removed if they expire (a default timeout is set upon creation).

config BIG_KEYS
	bool "Large payload keys"
	depends on KEYS
	depends on TMPFS
	depends on CRYPTO_LIB_CHACHA20POLY1305 = y
	help
	  This option provides support for holding large keys within the kernel
	  (for example Kerberos ticket caches).  The data may be stored out to
	  swapspace by tmpfs.

	  If you are unsure as to whether this is required, answer N.

config TRUSTED_KEYS
	tristate "TRUSTED KEYS"
	depends on KEYS && TCG_TPM
	select CRYPTO
	select CRYPTO_HMAC
	select CRYPTO_SHA1
	select CRYPTO_HASH_INFO
	select ASN1_ENCODER
	select OID_REGISTRY
	select ASN1
	help
	  This option provides support for creating, sealing, and unsealing
	  keys in the kernel. Trusted keys are random number symmetric keys,
	  generated and RSA-sealed by the TPM. The TPM only unseals the keys,
	  if the boot PCRs and other criteria match.  Userspace will only ever
	  see encrypted blobs.

	  If you are unsure as to whether this is required, answer N.

config ENCRYPTED_KEYS
	tristate "ENCRYPTED KEYS"
	depends on KEYS
	select CRYPTO
	select CRYPTO_HMAC
	select CRYPTO_AES
	select CRYPTO_CBC
	select CRYPTO_SHA256
	select CRYPTO_RNG
	help
	  This option provides support for create/encrypting/decrypting keys
	  in the kernel.  Encrypted keys are kernel generated random numbers,
	  which are encrypted/decrypted with a 'master' symmetric key. The
	  'master' key can be either a trusted-key or user-key type.
	  Userspace only ever sees/stores encrypted blobs.

	  If you are unsure as to whether this is required, answer N.

config KEY_DH_OPERATIONS
       bool "Diffie-Hellman operations on retained keys"
       depends on KEYS
       select CRYPTO
       select CRYPTO_HASH
       select CRYPTO_DH
       help
	 This option provides support for calculating Diffie-Hellman
	 public keys and shared secrets using values stored as keys
	 in the kernel.

	 If you are unsure as to whether this is required, answer N.

config KEY_NOTIFICATIONS
	bool "Provide key/keyring change notifications"
	depends on KEYS && WATCH_QUEUE
	help
	  This option provides support for getting change notifications
	  on keys and keyrings on which the caller has View permission.
	  This makes use of pipes to handle the notification buffer and
	  provides KEYCTL_WATCH_KEY to enable/disable watches.
Commit	Line	Data
ec8f24b7	1	# SPDX-License-Identifier: GPL-2.0-only
f0894940 DH	2	#
	3	# Key management configuration
	4	#
	5
	6	config KEYS
	7	bool "Enable access key retention support"
b2a4df20	8	select ASSOCIATIVE_ARRAY
f0894940 DH	9	help
	10	This option provides support for retaining authentication tokens and
	11	access keys in the kernel.
	12
	13	It also includes provision of methods by which such keys might be
	14	associated with a process so that network filesystems, encryption
	15	support and the like can find them.
	16
	17	Furthermore, a special type of key is available that acts as keyring:
	18	a searchable sequence of keys. Each process is equipped with access
	19	to five standard keyrings: UID-specific, GID-specific, session,
	20	process and thread.
	21
	22	If you are unsure as to whether this is required, answer N.
	23
7743c48e DH	24	config KEYS_REQUEST_CACHE
	25	bool "Enable temporary caching of the last request_key() result"
	26	depends on KEYS
	27	help
	28	This option causes the result of the last successful request_key()
	29	call that didn't upcall to the kernel to be cached temporarily in the
	30	task_struct. The cache is cleared by exit and just prior to the
	31	resumption of userspace.
	32
	33	This allows the key used for multiple step processes where each step
	34	wants to request a key that is likely the same as the one requested
	35	by the last step to save on the searching.
	36
	37	An example of such a process is a pathwalk through a network
	38	filesystem in which each method needs to request an authentication
	39	key. Pathwalk will call multiple methods for each dentry traversed
	40	(permission, d_revalidate, lookup, getxattr, getacl, ...).
	41
f36f8c75 DH	42	config PERSISTENT_KEYRINGS
	43	bool "Enable register of persistent per-UID keyrings"
	44	depends on KEYS
	45	help
	46	This option provides a register of persistent per-UID keyrings,
	47	primarily aimed at Kerberos key storage. The keyrings are persistent
	48	in the sense that they stay around after all processes of that UID
	49	have exited, not that they survive the machine being rebooted.
	50
	51	A particular keyring may be accessed by either the user whose keyring
	52	it is or by a process with administrative privileges. The active
	53	LSMs gets to rule on which admin-level processes get to access the
	54	cache.
	55
	56	Keyrings are created and added into the register upon demand and get
	57	removed if they expire (a default timeout is set upon creation).
	58
ab3c3587	59	config BIG_KEYS
2eaf6b5d	60	bool "Large payload keys"
ab3c3587 DH	61	depends on KEYS
ab3c3587 DH	62	depends on TMPFS
521fd61c	63	depends on CRYPTO_LIB_CHACHA20POLY1305 = y
ab3c3587 DH	64	help
	65	This option provides support for holding large keys within the kernel
	66	(for example Kerberos ticket caches). The data may be stored out to
	67	swapspace by tmpfs.
	68
	69	If you are unsure as to whether this is required, answer N.
	70
f0894940 DH	71	config TRUSTED_KEYS
	72	tristate "TRUSTED KEYS"
	73	depends on KEYS && TCG_TPM
	74	select CRYPTO
	75	select CRYPTO_HMAC
	76	select CRYPTO_SHA1
5ca4c20c	77	select CRYPTO_HASH_INFO
f2219745 JB	78	select ASN1_ENCODER
	79	select OID_REGISTRY
	80	select ASN1
f0894940 DH	81	help
	82	This option provides support for creating, sealing, and unsealing
	83	keys in the kernel. Trusted keys are random number symmetric keys,
	84	generated and RSA-sealed by the TPM. The TPM only unseals the keys,
	85	if the boot PCRs and other criteria match. Userspace will only ever
	86	see encrypted blobs.
	87
	88	If you are unsure as to whether this is required, answer N.
	89
	90	config ENCRYPTED_KEYS
	91	tristate "ENCRYPTED KEYS"
	92	depends on KEYS
	93	select CRYPTO
	94	select CRYPTO_HMAC
	95	select CRYPTO_AES
	96	select CRYPTO_CBC
	97	select CRYPTO_SHA256
	98	select CRYPTO_RNG
	99	help
	100	This option provides support for create/encrypting/decrypting keys
	101	in the kernel. Encrypted keys are kernel generated random numbers,
	102	which are encrypted/decrypted with a 'master' symmetric key. The
	103	'master' key can be either a trusted-key or user-key type.
	104	Userspace only ever sees/stores encrypted blobs.
	105
	106	If you are unsure as to whether this is required, answer N.
ddbb4114 MM	107
	108	config KEY_DH_OPERATIONS
	109	bool "Diffie-Hellman operations on retained keys"
	110	depends on KEYS
4cd4ca7c	111	select CRYPTO
f1c316a3	112	select CRYPTO_HASH
7cbe0932	113	select CRYPTO_DH
ddbb4114 MM	114	help
	115	This option provides support for calculating Diffie-Hellman
	116	public keys and shared secrets using values stored as keys
	117	in the kernel.
	118
	119	If you are unsure as to whether this is required, answer N.
f7e47677 DH	120
	121	config KEY_NOTIFICATIONS
	122	bool "Provide key/keyring change notifications"
	123	depends on KEYS && WATCH_QUEUE
	124	help
8fe62e0c GKB	125	This option provides support for getting change notifications
	126	on keys and keyrings on which the caller has View permission.
	127	This makes use of pipes to handle the notification buffer and
	128	provides KEYCTL_WATCH_KEY to enable/disable watches.