NAME

       add_key - add a key to the kernel's key management facility

SYNOPSIS

       #include <keyutils.h>

       key_serial_t add_key(const char *type, const char *description,
                            const void *payload, size_t plen,
                            key_serial_t keyring);

DESCRIPTION

       add_key()  asks  the  kernel  to create or update a key of the given type and description,
       instantiate it with the payload of length plen, and to attach it to the nominated  keyring
       and to return its serial number.

       The key type may reject the data if it's in the wrong format or in some other way invalid.

       If  the  destination  keyring  already  contains a key that matches the specified type and
       description, then, if the key type supports it, that key will be updated rather than a new
       key  being created; if not, a new key will be created and it will displace the link to the
       extant key from the keyring.

       The destination keyring serial number may be that of a valid keyring to which  the  caller
       has write permission, or it may be a special keyring ID:

       KEY_SPEC_THREAD_KEYRING
              This specifies the caller's thread-specific keyring.

       KEY_SPEC_PROCESS_KEYRING
              This specifies the caller's process-specific keyring.

       KEY_SPEC_SESSION_KEYRING
              This specifies the caller's session-specific keyring.

       KEY_SPEC_USER_KEYRING
              This specifies the caller's UID-specific keyring.

       KEY_SPEC_USER_SESSION_KEYRING
              This specifies the caller's UID-session keyring.

KEY TYPES

       There  are  a number of key types available in the core key management code, and these can
       be specified to this function:

       “user” Keys of the user-defined key type may contain a blob of  arbitrary  data,  and  the
              description may be any valid string, though it is preferred that the description be
              prefixed with a string representing the service to which the key is of interest and
              a  colon  (for instance “afs:mykey”).  The payload may be empty or NULL for keys of
              this type.

       “keyring”
              Keyrings are special key types that may contain links to sequences of other keys of
              any  type.   If  this  interface  is  used to create a keyring, then a NULL payload
              should be specified, and plen should be zero.

RETURN VALUE

       On success add_key() returns the serial number of the  key  it  created  or  updated.   On
       error, the value -1 will be returned and errno will have been set to an appropriate error.

ERRORS

       ENOKEY The keyring doesn't exist.

       EKEYEXPIRED
              The keyring has expired.

       EKEYREVOKED
              The keyring has been revoked.

       EINVAL The payload data was invalid.

       ENOMEM Insufficient memory to create a key.

       EDQUOT The key quota for this user would be exceeded by creating this key or linking it to
              the keyring.

       EACCES The keyring wasn't available for modification by the user.

LINKING

       Although this is a Linux system call, it is not present in libc but can be found rather in
       libkeyutils.  When linking, -lkeyutils should be specified to the linker.

SEE ALSO

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

COLOPHON

       This  page  is  part of release 4.04 of the Linux man-pages project.  A description of the
       project, information about reporting bugs, and the latest version of  this  page,  can  be
       found at http://www.kernel.org/doc/man-pages/.