1 # SPDX-License-Identifier: GPL-2.0-only
3 # Key management configuration
7 bool "Enable access key retention support"
8 select ASSOCIATIVE_ARRAY
10 This option provides support for retaining authentication tokens and
11 access keys in the kernel.
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.
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,
22 If you are unsure as to whether this is required, answer N.
24 config KEYS_REQUEST_CACHE
25 bool "Enable temporary caching of the last request_key() result"
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.
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.
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, ...).
42 config PERSISTENT_KEYRINGS
43 bool "Enable register of persistent per-UID keyrings"
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.
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
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).
60 bool "Large payload keys"
63 depends on CRYPTO_LIB_CHACHA20POLY1305 = y
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
69 If you are unsure as to whether this is required, answer N.
72 tristate "TRUSTED KEYS"
73 depends on KEYS && TCG_TPM
77 select CRYPTO_HASH_INFO
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
88 If you are unsure as to whether this is required, answer N.
91 tristate "ENCRYPTED KEYS"
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.
106 If you are unsure as to whether this is required, answer N.
108 config KEY_DH_OPERATIONS
109 bool "Diffie-Hellman operations on retained keys"
115 This option provides support for calculating Diffie-Hellman
116 public keys and shared secrets using values stored as keys
119 If you are unsure as to whether this is required, answer N.
121 config KEY_NOTIFICATIONS
122 bool "Provide key/keyring change notifications"
123 depends on KEYS && WATCH_QUEUE
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.