Linux kernel mirror (for testing)
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linux
1# SPDX-License-Identifier: GPL-2.0-only
2#
3# Key management configuration
4#
5
6menuconfig KEYS
7 bool "Enable access key retention support"
8 select ASSOCIATIVE_ARRAY
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
24if KEYS
25
26config KEYS_REQUEST_CACHE
27 bool "Enable temporary caching of the last request_key() result"
28 help
29 This option causes the result of the last successful request_key()
30 call that didn't upcall to the kernel to be cached temporarily in the
31 task_struct. The cache is cleared by exit and just prior to the
32 resumption of userspace.
33
34 This allows the key used for multiple step processes where each step
35 wants to request a key that is likely the same as the one requested
36 by the last step to save on the searching.
37
38 An example of such a process is a pathwalk through a network
39 filesystem in which each method needs to request an authentication
40 key. Pathwalk will call multiple methods for each dentry traversed
41 (permission, d_revalidate, lookup, getxattr, getacl, ...).
42
43config PERSISTENT_KEYRINGS
44 bool "Enable register of persistent per-UID keyrings"
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
59config BIG_KEYS
60 bool "Large payload keys"
61 depends on TMPFS
62 select CRYPTO_LIB_CHACHA20POLY1305
63 help
64 This option provides support for holding large keys within the kernel
65 (for example Kerberos ticket caches). The data may be stored out to
66 swapspace by tmpfs.
67
68 If you are unsure as to whether this is required, answer N.
69
70config TRUSTED_KEYS
71 tristate "TRUSTED KEYS"
72 help
73 This option provides support for creating, sealing, and unsealing
74 keys in the kernel. Trusted keys are random number symmetric keys,
75 generated and sealed by a trust source selected at kernel boot-time.
76 Userspace will only ever see encrypted blobs.
77
78 If you are unsure as to whether this is required, answer N.
79
80if TRUSTED_KEYS
81source "security/keys/trusted-keys/Kconfig"
82endif
83
84config ENCRYPTED_KEYS
85 tristate "ENCRYPTED KEYS"
86 select CRYPTO
87 select CRYPTO_AES
88 select CRYPTO_CBC
89 select CRYPTO_LIB_SHA256
90 select CRYPTO_RNG
91 help
92 This option provides support for create/encrypting/decrypting keys
93 in the kernel. Encrypted keys are instantiated using kernel
94 generated random numbers or provided decrypted data, and are
95 encrypted/decrypted with a 'master' symmetric key. The 'master'
96 key can be either a trusted-key or user-key type. Only encrypted
97 blobs are ever output to Userspace.
98
99 If you are unsure as to whether this is required, answer N.
100
101config USER_DECRYPTED_DATA
102 bool "Allow encrypted keys with user decrypted data"
103 depends on ENCRYPTED_KEYS
104 help
105 This option provides support for instantiating encrypted keys using
106 user-provided decrypted data. The decrypted data must be hex-ascii
107 encoded.
108
109 If you are unsure as to whether this is required, answer N.
110
111config KEY_DH_OPERATIONS
112 bool "Diffie-Hellman operations on retained keys"
113 select CRYPTO
114 select CRYPTO_KDF800108_CTR
115 select CRYPTO_DH
116 help
117 This option provides support for calculating Diffie-Hellman
118 public keys and shared secrets using values stored as keys
119 in the kernel.
120
121 If you are unsure as to whether this is required, answer N.
122
123config KEY_NOTIFICATIONS
124 bool "Provide key/keyring change notifications"
125 depends on WATCH_QUEUE
126 help
127 This option provides support for getting change notifications
128 on keys and keyrings on which the caller has View permission.
129 This makes use of pipes to handle the notification buffer and
130 provides KEYCTL_WATCH_KEY to enable/disable watches.
131
132endif # KEYS