keyrings(7) Miscellaneous Information Manual keyrings(7) keyrings - . add_key(2) request_key(2) keyctl(2). . keyctl(1) keyctl(3) keyutils(7) . : () . . key_serial_t. Type . . () ( ) . . () . . request_key(2). . . UNIX () ( ). . . . EKEYEXPIRED. ( ) ENOKEY. . (keyrings) . . : "keyring" ( ) . . () ('.') . "user" . . . 32,767 . ( "afs:mykey"). "logon" ( 3.3) "user" ( KEYCTL_READ keyctl(2)) . . "logon" . ( "user" ). "big_key" ( 3.13) "user" 1 . (Kerberos). tmpfs . ( . tmpfs.) 4.8 tmpfs (swap). . ('.') . ( ). . UNIX . ( ) : . . . . . . . . keyctl_clear(3) keyctl_link(3) keyctl_search(3) keyctl_unlink(3) . . : . . . . . . : session-keyring(7) ( ) process-keyring(7) ( ) thread-keyring(7) ( ). add_key(2) keyctl(2) request_key(2) KEY_SPEC_SESSION_KEYRING KEY_SPEC_PROCESS_KEYRING KEY_SPEC_THREAD_KEYRING . (UID) : user-keyring(7) user-session-keyring(7). UID . add_key(2) keyctl(2) request_key(2) KEY_SPEC_USER_KEYRING KEY_SPEC_USER_SESSION_KEYRING . pam_keyinit(8) . persistent-keyring(7) UID . UID . cron(8) . . . system keyring ( ) . . " " (GID) . KEY_SPEC_GROUP_KEYRING . . : (1) . (2) session-keyring(7) process-keyring(7) thread-keyring(7) . (3) . (4) (3) . (5) ( request_key(2)) (1) . . set-user-ID . UID GID. pam_keyinit(8) user-keyring(7) . : o o o o . . . : user . group . other . : possessor . . : view . ( ). read : . : () . write . ( ) search ( ): . : . link . . setattr . (LSM) . LSM keyctl_get_security(3). keyctl_chown(3) keyctl_describe(3) keyctl_get_security(3) keyctl_setperm(3) selinux(8) . . request_key(2) . ( .) : (1) : thread-keyring(7) process-keyring(7) session-keyring(7) user-session-keyring(7) . (2) upcall request_key(2) request_key(2) . (3) : . (4) . (5) . (6) ENOKEY. (3) (6) . request_key(2) keyctl_search(3) . request_key(2) callout_info upcall . . request-key(8) . . . request_key(2) keyctl_assume_authority(3) keyctl_instantiate(3) keyctl_negate(3) keyctl_reject(3) request-key(8) request-key.conf(5) . . : - DNS upcall upcall DNS . AF_RXRPC kAFS - AF_RXRPC AFS . AF_RXRPC kAFS. NFS - NFS . CIFS - CIFS . . . : MIT Kerberos 5 (libkrb5) cron(8) . /proc . /proc/keys ( 2.6.10) view . . view ( ). LSM . ( ) : (1) (2) (3)(4) (5) (6) (7) (8) (9) 009a2028 I--Q--- 1 perm 3f010000 1000 1000 user krb_ccache:primary: 12 1806c4ba I--Q--- 1 perm 3f010000 1000 1000 keyring _pid: 2 25d3a08f I--Q--- 1 perm 1f3f0000 1000 65534 keyring _uid_ses.1000: 1 28576bd8 I--Q--- 3 perm 3f010000 1000 1000 keyring _krb: 1 2c546d21 I--Q--- 190 perm 3f030000 1000 1000 keyring _ses: 2 30a4e0be I------ 4 2d 1f030000 1000 65534 keyring _persistent.1000: 1 32100fab I--Q--- 4 perm 1f3f0000 1000 65534 keyring _uid.1000: 2 32a387ea I--Q--- 1 perm 3f010000 1000 1000 keyring _pid: 2 3ce56aea I--Q--- 5 perm 3f030000 1000 1000 keyring _ses: 1 : (1) ( ) . (2) : I . R . D ( ). ( ). Q . U request-key(2). N . i . (3) (: ). (4) ( ). perm ( ). expd . (5) . : 0x01 view 0x02 read 0x04 write 0x08 search 0x10 link 0x20 setattr UID (6) . GID (7) . -1 . (8) ( .) (9) (). . name[: extra-info] name (). extra-info . : "user" "logon" ( ). "keyring" empty . "big_key" [file] tmpfs(5) ( ) [buff] . ".request_key_auth" ( request_key(2)) : key:c9a9b19 pid:28880 ci:10 : key . pid (PID) . ci ( ). /proc/key-users ( 2.6.10) . : 0: 10 9/9 2/1000000 22/25000000 42: 9 9/9 8/200 106/20000 1000: 11 11/11 10/200 271/20000 : uid . usage . nkeys/nikeys . qnkeys/maxkeys . qnbytes/maxbytes . /proc/sys/kernel/keys/gc_delay ( 2.6.32) . (EKEYREVOKED EKEYEXPIRED ) . 300 ( 5 ). /proc/sys/kernel/keys/persistent_keyring_expiry ( 3.13) ( keyctl_get_persistent(3) KEYCTL_GET_PERSISTENT keyctl(2).) 259200 ( 3 ). ( ) (quotas) : /proc/sys/kernel/keys/maxbytes ( 2.6.26) (nonroot) . 20,000. /proc/sys/kernel/keys/maxkeys ( 2.6.26) (nonroot). 200. /proc/sys/kernel/keys/root_maxbytes ( 2.6.26) (root) ( 0 ) . 25,000,000 ( 20,000 3.17). /proc/sys/kernel/keys/root_maxkeys ( 2.6.26) (root) ( 0 ). 1,000,000 ( 200 3.17). 4 . keyctl(1), add_key(2), keyctl(2), request_key(2), keyctl(3), keyutils(7), persistent-keyring(7), process-keyring(7), session-keyring(7), thread-keyring(7), user-keyring(7), user-session-keyring(7), pam_keyinit(8), request-key(8) linux.git/Documentation/crypto/asymmetric-keys.rst linux.git/Documentation/security/keys/ 3 . . : . 6.18 8 2026 keyrings(7)