1# 2# Key management configuration 3# 4 5config KEYS 6 bool "Enable access key retention support" 7 select ASSOCIATIVE_ARRAY 8 help 9 This option provides support for retaining authentication tokens and 10 access keys in the kernel. 11 12 It also includes provision of methods by which such keys might be 13 associated with a process so that network filesystems, encryption 14 support and the like can find them. 15 16 Furthermore, a special type of key is available that acts as keyring: 17 a searchable sequence of keys. Each process is equipped with access 18 to five standard keyrings: UID-specific, GID-specific, session, 19 process and thread. 20 21 If you are unsure as to whether this is required, answer N. 22 23config PERSISTENT_KEYRINGS 24 bool "Enable register of persistent per-UID keyrings" 25 depends on KEYS 26 help 27 This option provides a register of persistent per-UID keyrings, 28 primarily aimed at Kerberos key storage. The keyrings are persistent 29 in the sense that they stay around after all processes of that UID 30 have exited, not that they survive the machine being rebooted. 31 32 A particular keyring may be accessed by either the user whose keyring 33 it is or by a process with administrative privileges. The active 34 LSMs gets to rule on which admin-level processes get to access the 35 cache. 36 37 Keyrings are created and added into the register upon demand and get 38 removed if they expire (a default timeout is set upon creation). 39 40config BIG_KEYS 41 bool "Large payload keys" 42 depends on KEYS 43 depends on TMPFS 44 help 45 This option provides support for holding large keys within the kernel 46 (for example Kerberos ticket caches). The data may be stored out to 47 swapspace by tmpfs. 48 49 If you are unsure as to whether this is required, answer N. 50 51config TRUSTED_KEYS 52 tristate "TRUSTED KEYS" 53 depends on KEYS && TCG_TPM 54 select CRYPTO 55 select CRYPTO_HMAC 56 select CRYPTO_SHA1 57 help 58 This option provides support for creating, sealing, and unsealing 59 keys in the kernel. Trusted keys are random number symmetric keys, 60 generated and RSA-sealed by the TPM. The TPM only unseals the keys, 61 if the boot PCRs and other criteria match. Userspace will only ever 62 see encrypted blobs. 63 64 If you are unsure as to whether this is required, answer N. 65 66config ENCRYPTED_KEYS 67 tristate "ENCRYPTED KEYS" 68 depends on KEYS 69 select CRYPTO 70 select CRYPTO_HMAC 71 select CRYPTO_AES 72 select CRYPTO_CBC 73 select CRYPTO_SHA256 74 select CRYPTO_RNG 75 help 76 This option provides support for create/encrypting/decrypting keys 77 in the kernel. Encrypted keys are kernel generated random numbers, 78 which are encrypted/decrypted with a 'master' symmetric key. The 79 'master' key can be either a trusted-key or user-key type. 80 Userspace only ever sees/stores encrypted blobs. 81 82 If you are unsure as to whether this is required, answer N. 83 84config KEYS_DEBUG_PROC_KEYS 85 bool "Enable the /proc/keys file by which keys may be viewed" 86 depends on KEYS 87 help 88 This option turns on support for the /proc/keys file - through which 89 can be listed all the keys on the system that are viewable by the 90 reading process. 91 92 The only keys included in the list are those that grant View 93 permission to the reading process whether or not it possesses them. 94 Note that LSM security checks are still performed, and may further 95 filter out keys that the current process is not authorised to view. 96 97 Only key attributes are listed here; key payloads are not included in 98 the resulting table. 99 100 If you are unsure as to whether this is required, answer N. 101