man7/process-keyring.7

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.TH PROCESS-KEYRING 7 2020-08-13 Linux "Linux Programmer's Manual"
.SH NAME
process-keyring \- per-process shared keyring
.SH DESCRIPTION
The process keyring is a keyring used to anchor keys on behalf of a process.
It is created only when a process requests it.
The process keyring has the name (description)
.IR _pid .
.PP
A special serial number value,
.BR KEY_SPEC_PROCESS_KEYRING ,
is defined that can be used in lieu of the actual serial number of
the calling process's process keyring.
.PP
From the
.BR keyctl (1)
utility, '\fB@p\fP' can be used instead of a numeric key ID in
much the same way, but since
.BR keyctl (1)
is a program run after forking, this is of no utility.
.PP
A thread created using the
.BR clone (2)
.B CLONE_THREAD
flag has the same process keyring as the caller of
.BR clone (2).
When a new process is created using
.BR fork ()
it initially has no process keyring.
A process's process keyring is cleared on
.BR execve (2).
The process keyring is destroyed when the last
thread that refers to it terminates.
.PP
If a process doesn't have a process keyring when it is accessed,
then the process keyring will be created if the keyring is to be modified;
otherwise, the error
.B ENOKEY
results.
.SH SEE ALSO
.ad l
.nh
.BR keyctl (1),
.BR keyctl (3),
.BR keyrings (7),
.BR persistent\-keyring (7),
.BR session\-keyring (7),
.BR thread\-keyring (7),
.BR user\-keyring (7),
.BR user\-session\-keyring (7)