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 133