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KEYCTL_SETPERM(3)         Linux Key Management Calls         KEYCTL_SETPERM(3)
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)
Linux                             4 May 2006                 KEYCTL_SETPERM(3)