NAME

       keyctl_setperm - change the permissions mask on a key

SYNOPSIS

       #include <keyutils.h>

       long keyctl_setperm(key_serial_t key, key_perm_t perm);

DESCRIPTION

       keyctl_setperm() changes the permissions mask on a key.

       A  process  that  does not have the SysAdmin capability may not change the permissions mask on a key that
       doesn't have the same UID as the caller.

       The caller must have setattr permission on a key to be able change its permissions mask.

       The permissions mask is a bitwise-OR of the following flags:

       KEY_xxx_VIEW
              Grant permission to view the attributes of a key.

       KEY_xxx_READ
              Grant permission to read the payload of a key or to list a keyring.

       KEY_xxx_WRITE
              Grant permission to modify the payload of a key or to add or remove links to/from a keyring.

       KEY_xxx_SEARCH
              Grant permission to find a key or to search a keyring.

       KEY_xxx_LINK
              Grant permission to make links to a key.

       KEY_xxx_SETATTR
              Grant permission to change the ownership and permissions attributes of a key.

       KEY_xxx_ALL
              Grant all the above.

       The 'xxx' in the above should be replaced by one of:

       POS    Grant the permission to a process that possesses the key (has it attached searchably to one of the
              process's keyrings).

       USR    Grant the permission to a process with the same UID as the key.

       GRP    Grant  the permission to a process with the same GID as the key, or with a match for the key's GID
              amongst that process's Groups list.

       OTH    Grant the permission to any other process.

       Examples include: KEY_POS_VIEW, KEY_USR_READ, KEY_GRP_SEARCH and KEY_OTH_ALL.

       User, group and other grants are exclusive: if a process qualifies in the 'user' category,  it  will  not
       qualify  in  the  'groups' category; and if a process qualifies in either 'user' or 'groups' then it will
       not qualify in the 'other' category.

       Possessor grants are cumulative with the grants from the 'user', 'groups' and 'other' categories.

RETURN VALUE

       On success keyctl_setperm() returns 0 .  On error, the value -1 will be returned and errno will have been
       set to an appropriate error.

ERRORS

       ENOKEY The specified key does not exist.

       EKEYEXPIRED
              The specified key has expired.

       EKEYREVOKED
              The specified key has been revoked.

       EACCES The named key exists, but does not grant setattr permission to the calling process.

LINKING

       This  is  a  library  function  that  can  be  found  in libkeyutils.  When linking, -lkeyutils should be
       specified to the linker.

SEE ALSO

       keyctl(1), add_key(2), keyctl(2), request_key(2), keyctl(3), keyrings(7), keyutils(7)