KEYCTL_SETPERM(2const) - Linux manual page (original) (raw)

KEYCTLSETPERM(2const) KEYCTLSETPERM(2const)

NAME top

   KEYCTL_SETPERM - change the permissions mask on a key

LIBRARY top

   Standard C library (_libc_, _-lc_)

SYNOPSIS top

   **#include <linux/keyctl.h>** /* Definition of **KEY*** constants */
   **#include <sys/syscall.h>** /* Definition of **SYS_*** constants */
   **#include <unistd.h>**

   **long syscall(SYS_keyctl, KEYCTL_SETPERM, key_serial_t** _key_**,**
                **key_perm_t** _perms_**);**

DESCRIPTION top

   Change the permissions of the key with the ID provided in the _key_
   argument to the permissions provided in the _perms_ argument.

   If the caller doesn't have the **CAP_SYS_ADMIN** capability, it can
   change permissions only for the keys it owns.  (More precisely:
   the caller's filesystem UID must match the UID of the key.)

   The key must grant _setattr_ permission to the caller _regardless_ of
   the caller's capabilities.

   The permissions in _perms_ specify masks of available operations for
   each of the following user categories:

   _possessor_ (since Linux 2.6.14)
          This is the permission granted to a process that possesses
          the key (has it attached searchably to one of the process's
          keyrings); see [keyrings(7)](../man7/keyrings.7.html).

   _user_   This is the permission granted to a process whose
          filesystem UID matches the UID of the key.

   _group_  This is the permission granted to a process whose
          filesystem GID or any of its supplementary GIDs matches the
          GID of the key.

   _other_  This is the permission granted to other processes that do
          not match the _user_ and _group_ categories.

   The _user_, _group_, and _other_ categories are exclusive: if a process
   matches the _user_ category, it will not receive permissions granted
   in the _group_ category; if a process matches the _user_ or _group_
   category, then it will not receive permissions granted in the
   _other_ category.

   The _possessor_ category grants permissions that are cumulative with
   the grants from the _user_, _group_, or _other_ category.

   Each permission mask is eight bits in size, with only six bits
   currently used.  The available permissions are:

   _view_   This permission allows reading attributes of a key.

          This permission is required for the [KEYCTL_DESCRIBE(2const)](../man2/KEYCTL%5FDESCRIBE.2const.html)
          operation.

   The permission bits for each category are:

          **KEY_POS_VIEW**
          **KEY_USR_VIEW**
          **KEY_GRP_VIEW**
          **KEY_OTH_VIEW**

   _read_   This permission allows reading a key's payload.

          This permission is required for the [KEYCTL_READ(2const)](../man2/KEYCTL%5FREAD.2const.html)
          operation.

          The permission bits for each category are

          **KEY_POS_READ**
          **KEY_USR_READ**
          **KEY_GRP_READ**
          **KEY_OTH_READ**

   _write_  This permission allows update or instantiation of a key's
          payload.  For a keyring, it allows keys to be linked and
          unlinked from the keyring,

          This permission is required for the [KEYCTL_UPDATE(2const)](../man2/KEYCTL%5FUPDATE.2const.html),
          [KEYCTL_REVOKE(2const)](../man2/KEYCTL%5FREVOKE.2const.html), [KEYCTL_CLEAR(2const)](../man2/KEYCTL%5FCLEAR.2const.html),
          [KEYCTL_LINK(2const)](../man2/KEYCTL%5FLINK.2const.html), and [KEYCTL_UNLINK(2const)](../man2/KEYCTL%5FUNLINK.2const.html) operations.

          The permission bits for each category are:

          **KEY_POS_WRITE**
          **KEY_USR_WRITE**
          **KEY_GRP_WRITE**
          **KEY_OTH_WRITE**

   _search_ This permission allows keyrings to be searched and keys to
          be found.  Searches can recurse only into nested keyrings
          that have _search_ permission set.

          This permission is required for the
          [KEYCTL_GET_KEYRING_ID(2const)](../man2/KEYCTL%5FGET%5FKEYRING%5FID.2const.html),
          [KEYCTL_JOIN_SESSION_KEYRING(2const)](../man2/KEYCTL%5FJOIN%5FSESSION%5FKEYRING.2const.html), [KEYCTL_SEARCH(2const)](../man2/KEYCTL%5FSEARCH.2const.html),
          and **KEYCTL_INVALIDATE (2const)** operations.

          The permission bits for each category are:

          **KEY_POS_SEARCH**
          **KEY_USR_SEARCH**
          **KEY_GRP_SEARCH**
          **KEY_OTH_SEARCH**

   _link_   This permission allows a key or keyring to be linked to.

          This permission is required for the [KEYCTL_LINK(2const)](../man2/KEYCTL%5FLINK.2const.html) and
          [KEYCTL_SESSION_TO_PARENT(2const)](../man2/KEYCTL%5FSESSION%5FTO%5FPARENT.2const.html) operations.

          The permission bits for each category are:

          **KEY_POS_LINK**
          **KEY_USR_LINK**
          **KEY_GRP_LINK**
          **KEY_OTH_LINK**

   _setattr_ (since Linux 2.6.15)
          This permission allows a key's UID, GID, and permissions
          mask to be changed.

          This permission is required for the [KEYCTL_REVOKE(2const)](../man2/KEYCTL%5FREVOKE.2const.html),
          [KEYCTL_CHOWN(2const)](../man2/KEYCTL%5FCHOWN.2const.html), and **KEYCTL_SETPERM (2const)**
          operations.

          The permission bits for each category are:

          **KEY_POS_SETATTR**
          **KEY_USR_SETATTR**
          **KEY_GRP_SETATTR**
          **KEY_OTH_SETATTR**

   As a convenience, the following macros are defined as masks for
   all of the permission bits in each of the user categories:

          **KEY_POS_ALL**
          **KEY_USR_ALL**
          **KEY_GRP_ALL**
          **KEY_OTH_ALL**

RETURN VALUE top

   On success, 0 is returned.

   On error, -1 is returned, and _[errno](../man3/errno.3.html)_ is set to indicate the error.

ERRORS top

   **EINVAL** _operation_ was **KEYCTL_SETPERM** and an invalid permission bit
          was specified in _perms_.

VERSIONS top

   A wrapper is provided in the _libkeyutils_ library:
   [keyctl_setperm(3)](../man3/keyctl%5Fsetperm.3.html).

STANDARDS top

   Linux.

HISTORY top

   Linux 2.6.10.

SEE ALSO top

   [keyctl(2)](../man2/keyctl.2.html), [keyctl_setperm(3)](../man3/keyctl%5Fsetperm.3.html)

COLOPHON top

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Linux man-pages 6.10 2024-08-21 KEYCTLSETPERM(2const)

Pages that refer to this page:keyctl(2)