Section: Linux Key Management Calls (2)
Return to Main Contents
add_key - add a key to the kernel's key management facility
key_serial_t add_key(const char *type, const char *description,
const void *payload, size_t plen,
asks the kernel to create or update a key of the given
instantiate it with the
and to attach it to the nominated
and to return its serial number.
The key type may reject the data if it's in the wrong format or in some other
If the destination
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.
serial number may be that of a valid keyring to which the caller has write
permission, or it may be a special keyring ID:
This specifies the caller's thread-specific keyring.
This specifies the caller's process-specific keyring.
This specifies the caller's session-specific keyring.
This specifies the caller's UID-specific keyring.
This specifies the caller's UID-session keyring.
There are a number of key types available in the core key management code, and
these can be specified to this function:
Keys of the user-defined key type may contain a blob of arbitrary data, and the
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
may be empty or NULL for keys of this type.
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
should be specified, and
should be zero.
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.
The keyring doesn't exist.
The keyring has expired.
The keyring has been revoked.
The payload data was invalid.
Insufficient memory to create a key.
The key quota for this user would be exceeded by creating this key or linking
it to the keyring.
The keyring wasn't available for modification by the user.
Although this is a Linux system call, it is not present in
but can be found rather in
should be specified to the linker.
This page is part of release 3.74 of the Linux
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
- KEY TYPES
- RETURN VALUE
- SEE ALSO