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),
       request-key(8)

Linux								    4 May 2006							 KEYCTL_SETPERM(3)