keyctl


SYNOPSIS
       keyctl show
       keyctl add <type> <desc> <data> <keyring>
       keyctl padd <type> <desc> <keyring>
       keyctl request <type> <desc> [<dest_keyring>]
       keyctl request2 <type> <desc> <info> [<dest_keyring>]
       keyctl prequest2 <type> <desc> [<dest_keyring>]
       keyctl update <key> <data>
       keyctl pupdate <key>
       keyctl newring <name> <keyring>
       keyctl revoke <key>
       keyctl clear <keyring>
       keyctl link <key> <keyring>
       keyctl unlink <key> <keyring>
       keyctl search <keyring> <type> <desc> [<dest_keyring>]
       keyctl read <key>
       keyctl pipe <key>
       keyctl print <key>
       keyctl list <keyring>
       keyctl rlist <keyring>
       keyctl describe <keyring>
       keyctl rdescribe <keyring> [sep]
       keyctl chown <key> <uid>
       keyctl chgrp <key> <gid>
       keyctl setperm <key> <mask>
       keyctl session
       keyctl session - [<prog> <arg1> <arg2> ...]
       keyctl session <name> [<prog> <arg1> <arg2> ...]
       keyctl instantiate <key> <data> <keyring>
       keyctl pinstantiate <key> <keyring>
       keyctl negate <key> <timeout> <keyring>
       keyctl reject <key> <timeout> <error> <keyring>
       keyctl timeout <key> <timeout>
       keyctl security <key>
       keyctl reap [-v]
       keyctl purge <type>
       keyctl purge [-i] [-p] <type> <desc>
       keyctl purge -s <type> <desc>

DESCRIPTION
       This  program is used to control the key management facility in various
       ways using a variety of subcommands.

KEY IDENTIFIERS
       The key identifiers passed to or returned from keyctl are, in  general,
       positive integers. There are, however, some special values with special
       meanings that can be passed as arguments:

       (*) No key: 0

       (*) Thread keyring: @t or -1

       Each thread may have its own keyring. This is  searched  first,  before
       Session  keyrings  can  be named and an extant keyring can be joined in
       place of a process's current session keyring.

       (*) User specific keyring: @u or -4

       This keyring is shared between all the processes owned by a  particular
       user.  It  isn't  searched directly, but is normally linked to from the
       session keyring.

       (*) User default session keyring: @us or -5

       This is the default session keyring for a particular user.  Login  pro-
       cesses that change to a particular user will bind to this session until
       another session is set.

       (*) Group specific keyring: @g or -6

       This is a place holder for a group specific keyring, but is  not  actu-
       ally implemented yet in the kernel.

       (*) Assumed request_key authorisation key: @a or -7

       This selects the authorisation key provided to the request_key() helper
       to permit it to access the callers keyrings and instantiate the  target
       key.

COMMAND SYNTAX
       Any  non-ambiguous  shortening of a command name may be used in lieu of
       the full command name. This facility should not be used in scripting as
       new commands may be added in future that then cause ambiguity.

       (*) Show process keyrings

       keyctl show

       This command recursively shows what keyrings a process is subscribed to
       and what keys and keyrings they contain.

       (*) Add a key to a keyring

       keyctl add <type> <desc> <data> <keyring>
       keyctl padd <type> <desc> <keyring>

       This command creates a key  of  the  specified  type  and  description;
       instantiates  it  with  the given data and attaches it to the specified
       keyring. It then prints the new key's ID on stdout:

              testbox>keyctl add user mykey stuff @u
              26

       The padd variant of the command reads the data from stdin  rather  than
       taking it from the command line:

              testbox>echo -n stuff | keyctl padd user mykey @u

       If there is no key, the first command  will  simply  return  the  error
       ENOKEY  and  fail.  The second and third commands will create a partial
       key with the type and description, and call  out  to  /sbin/request-key
       with  that  key  and  the  extra  information  supplied. This will then
       attempt to instantiate the key in some manner, such that a valid key is
       obtained.

       The  third command is like the second, except that the callout informa-
       tion is read from stdin rather than being passed on the command line.

       If a valid key is obtained, the ID will be printed and the key attached
       as if the original search had succeeded.

       If  there wasn't a valid key obtained, a temporary negative key will be
       attached to the destination keyring if given and the  error  "Requested
       key not available" will be given.

              testbox>keyctl request2 user debug:hello wibble
              23
              testbox>echo -n wibble | keyctl prequest2 user debug:hello
              23
              testbox>keyctl request user debug:hello
              23

       (*) Update a key

       keyctl update <key> <data>
       keyctl pupdate <key>

       This  command  replaces  the  data  attached to a key with a new set of
       data. If the type of the key doesn't support update then error  "Opera-
       tion not supported" will be returned.

              testbox>keyctl update 23 zebra

       The  pupdate  variant  of  the command reads the data from stdin rather
       than taking it from the command line:

              testbox>echo -n zebra | keyctl pupdate 23

       (*) Create a keyring

       keyctl newring <name> <keyring>

       This command creates a new keyring of the specified name  and  attaches
       it  to the specified keyring. The ID of the new keyring will be printed
       to stdout if successful.

              testbox>keyctl newring squelch @us
              27

       (*) Revoke a key

       keyctl clear <keyring>

       This command unlinks all the keys attached to  the  specified  keyring.
       Error  "Not a directory" will be returned if the key specified is not a
       keyring.

              testbox>keyctl clear 27

       (*) Link a key to a keyring

       keyctl link <key> <keyring>

       This command makes a link from the key to the keyring if there's enough
       capacity to do so. Error "Not a directory" will be returned if the des-
       tination is not a keyring. Error "Permission denied" will  be  returned
       if  the  key  doesn't  have link permission or the keyring doesn't have
       write permission. Error "File table overflow" will be returned  if  the
       keyring  is full. Error "Resource deadlock avoided" will be returned if
       an attempt was made to introduce a recursive link.

              testbox>keyctl link 23 27
              testbox>keyctl link 27 27
              keyctl_link: Resource deadlock avoided

       (*) Unlink a key from a keyring or the session keyring tree

       keyctl unlink <key> [<keyring>]

       If the keyring is specified, this command removes a  link  to  the  key
       from  the keyring. Error "Not a directory" will be returned if the des-
       tination is not a keyring. Error "Permission denied" will  be  returned
       if  the  keyring  doesn't have write permission. Error "No such file or
       directory" will be returned if the key is not linked to by the keyring.

       If the keyring is not specified, this command  performs  a  depth-first
       search  of  the  session  keyring tree and removes all the links to the
       nominated key that it finds (and that it is permitted to  remove).   It
       prints the number of successful unlinks before exiting.

              testbox>keyctl unlink 23 27

       (*) Search a keyring

       keyctl search <keyring> <type> <desc> [<dest_keyring>]

       This command non-recursively searches a keyring for a key of a particu-
       lar type and description. If found, the ID of the key will  be  printed
       on  stdout  and  the key will be attached to the destination keyring if
       present. Error "Requested key not available" will be  returned  if  the
       key is not found.

              testbox>keyctl search @us user debug:hello
              23
              testbox>keyctl search @us user debug:bye

       If the key type does not support reading of  the  payload,  then  error
       "Operation not supported" will be returned.

              testbox>keyctl read 26
              1 bytes of data in key:
              62
              testbox>keyctl print 26
              b
              testbox>keyctl pipe 26
              btestbox>

       (*) List a keyring

       keyctl list <keyring>
       keyctl rlist <keyring>

       These  commands  list the contents of a key as a keyring. "list" pretty
       prints the contents and "rlist" just produces a space-separated list of
       key IDs.

       No attempt is made to check that the specified keyring is a keyring.

              testbox>keyctl list @us
              2 keys in keyring:
                     22: vrwsl----------  4043    -1 keyring: _uid.4043
                     23: vrwsl----------  4043  4043 user: debug:hello
              testbox>keyctl rlist @us
              22 23

       (*) Describe a key

       keyctl describe <keyring>
       keyctl rdescribe <keyring> [sep]

       These  commands  fetch  a  description  of a keyring. "describe" pretty
       prints the description in the same fashion as the "list" command; "rde-
       scribe" prints the raw data returned from the kernel.

              testbox>keyctl describe @us
                     -5:  vrwsl----------   4043     -1 keyring: _uid_ses.4043
              testbox>keyctl                   rdescribe                   @us
              keyring;4043;-1;3f1f0000;_uid_ses.4043

       The raw string is "<type>;<uid>;<gid>;<perms>;<description>", where uid
       and gid are the decimal user and group IDs, perms  is  the  permissions
       mask  in  hex,  type  and description are the type name and description
       strings (neither of which will contain semicolons).

       (*) Change the access controls on a key

       keyctl chown <key> <uid>
       keyctl chgrp <key> <gid>

              keyctl_chown: Operation not supported
              testbox>sudo keyctl chgrp 27 0

       (*) Set the permissions mask on a key

       keyctl setperm <key> <mask>

       This command changes the permission control mask on a key. The mask may
       be specified as a hex number if it begins "0x", an octal number  if  it
       begins "0" or a decimal number otherwise.

       The hex numbers are a combination of:

              Possessor UID       GID       Other     Permission Granted
              ========  ========  ========  ========  ==================
              01000000  00010000  00000100  00000001  View
              02000000  00020000  00000200  00000002  Read
              04000000  00040000  00000400  00000004  Write
              08000000  00080000  00000800  00000008  Search
              10000000  00100000  00001000  00000010  Link
              20000000  00200000  00002000  00000020  Set Attribute
              3f000000  003f0000  00003f00  0000003f  All

       View  permits the type, description and other parameters of a key to be
       viewed.

       Read permits the payload (or keyring list) to be read if  supported  by
       the type.

       Write permits the payload (or keyring list) to be modified or updated.

       Search  on  a  key permits it to be found when a keyring to which it is
       linked is searched.

       Link permits a key to be linked to a keyring.

       Set Attribute permits a key to have its owner, group  membership,  per-
       missions mask and timeout changed.

              testbox>keyctl setperm 27 0x1f1f1f00

       (*) Start a new session with fresh keyrings

       keyctl session
       keyctl session - [<prog> <arg1> <arg2> ...]
       keyctl session <name> [<prog> <arg1> <arg2> ...]

       These  commands  join  or  create a new keyring and then run a shell or
       other program with that keyring as the session key.

       The variation with no  arguments  just  creates  an  anonymous  session
       keyring  and  attaches  that  as  the  session  keyring; it then exec's
       $SHELL.

              Joined session keyring: 28
              testbox>keyctl rdescribe @s
              keyring;4043;4043;3f1f0000;_ses.24082

              testbox>keyctl session -
              Joined session keyring: 29
              testbox>keyctl rdescribe @s
              keyring;4043;4043;3f1f0000;_ses.24139

              testbox>keyctl session - keyctl rdescribe @s
              Joined session keyring: 30
              keyring;4043;4043;3f1f0000;_ses.24185

              testbox>keyctl session fish
              Joined session keyring: 34
              testbox>keyctl rdescribe @s
              keyring;4043;4043;3f1f0000;fish

              testbox>keyctl session fish keyctl rdesc @s
              Joined session keyring: 35
              keyring;4043;4043;3f1f0000;fish

       (*) Instantiate a key

       keyctl instantiate <key> <data> <keyring>
       keyctl pinstantiate <key> <keyring>
       keyctl negate <key> <timeout> <keyring>
       keyctl reject <key> <timeout> <error> <keyring>

       These commands are used to attach data to a partially set  up  key  (as
       created  by the kernel and passed to /sbin/request-key).  "instantiate"
       marks a key as being valid  and  attaches  the  data  as  the  payload.
       "negate" and "reject" mark a key as invalid and sets a timeout on it so
       that it'll go away after a while.   This  prevents  a  lot  of  quickly
       sequential requests from slowing the system down overmuch when they all
       fail, as all subsequent requests will then fail with  error  "Requested
       key  not found" (if negated) or the specified error (if rejected) until
       the negative key has expired.

       Reject's error argument can either be a UNIX error  number  or  one  of
       'rejected', 'expired' or 'revoked'.

       The newly instantiated key will be attached to the specified keyring.

       These  commands may only be run from the program run by request-key - a
       special authorisation key is set up by the kernel and attached  to  the
       request-key's session keyring. This special key is revoked once the key
       to which it refers has been instantiated one way or another.

              testbox>keyctl instantiate $1 "Debug $3" $4
              testbox>keyctl negate $1 30 $4
              testbox>keyctl reject $1 30 64 $4

       The pinstantiate variant of the  command  reads  the  data  from  stdin
              testbox>keyctl timeout $1 45

       (*) Retrieve a key's security context

       keyctl security <key>

       This  command  is  used  to retrieve a key's LSM security context.  The
       label is printed on stdout.

              testbox>keyctl security @s
              unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023

       (*) Give the parent process a new session keyring

       keyctl new_session

       This command is used to give the invoking process (typically a shell) a
       new session keyring, discarding its old session keyring.

              testbox> keyctl session foo
              Joined session keyring: 723488146
              testbox> keyctl show
              Session Keyring
                     -3 --alswrv      0     0  keyring: foo
              testbox> keyctl new_session
              490511412
              testbox> keyctl show
              Session Keyring
                     -3 --alswrv      0     0  keyring: _ses

       Note  that this affects the parent of the process that invokes the sys-
       tem call, and so may only affect processes with  matching  credentials.
       Furthermore,  the  change  does not take effect till the parent process
       next transitions from kernel space to user space - typically  when  the
       wait() system call returns.

       (*) Remove dead keys from the session keyring tree

       keyctl reap

       This  command  performs  a  depth-first  search of the caller's session
       keyring tree and attempts to unlink any key that it finds that is inac-
       cessible due to expiry, revocation, rejection or negation.  It does not
       attempt to remove live keys that are unavailable simply due to  a  lack
       of granted permission.

       A  key  that is designated reapable will only be removed from a keyring
       if the caller has Write permission on that keyring, and  only  keyrings
       that grant Search permission to the caller will be searched.

       The  command  prints the number of keys reaped before it exits.  If the
       -v flag is passed then the reaped keys  are  listed  as  they're  being
       reaped, together with the success or failure of the unlink.

       Keys can only be removed from keyrings that grant Write permission.

       The first variant purges all keys of the specified type.

       The  second  variant  purges  all  keys of the specified type that also
       match the given description literally.  The -i flag allows a case-inde-
       pendent match and the -p flag allows a prefix match.

       The  third  variant  purges all keys of the specified type and matching
       description using the key type's comparator in the kernel to match  the
       description.   This  permits the key type to match a key with a variety
       of descriptions.

ERRORS
       There are a number of common errors returned by this program:

       "Not a directory" - a key wasn't a keyring.

       "Requested key not found" - the looked for key isn't available.

       "Key has been revoked" - a revoked key was accessed.

       "Key has expired" - an expired key was accessed.

       "Permission denied" - permission was denied by a UID/GID/mask  combina-
       tion.


SEE ALSO
       keyctl(1), request-key.conf(5)



Linux                             17 Nov 2005                        KEYCTL(1)
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