keyctl_get_security.3

.\"
.\" Copyright (C) 2010 Red Hat, Inc. All Rights Reserved.
.\" Written by David Howells (dhowells@redhat.com)
.\"
.\" This program is free software; you can redistribute it and/or
.\" modify it under the terms of the GNU General Public License
.\" as published by the Free Software Foundation; either version
.\" 2 of the License, or (at your option) any later version.
.\"
.TH KEYCTL_GET_SECURITY 3 "26 Feb 2010" Linux "Linux Key Management Calls"
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.SH NAME
keyctl_get_security \- Retrieve a key's security context
.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.SH SYNOPSIS
.nf
.B #include <keyutils.h>
.sp
.BI "long keyctl_get_security(key_serial_t " key ", char *" buffer ,
.BI "size_t " buflen ");"
.sp
.BI "long keyctl_get_security_alloc(key_serial_t " key ", char **" _buffer ");"
.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.SH DESCRIPTION
.BR keyctl_get_security ()
retrieves the security context of a key as a NUL-terminated string.  This will
be rendered in a form appropriate to the LSM in force - for instance, with
SELinux, it may look like
.IP
.B "unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023"
.P
The caller must have
.B view
permission on a key to be able to get its security context.
.P
.I buffer
and
.I buflen
specify the buffer into which the string will be placed.  If the buffer is too
small, the full size of the string will be returned, and no copy will take
place.
.P
.BR keyctl_get_security_alloc ()
is similar to
.BR keyctl_get_security ()
except that it allocates a buffer big enough to hold the string and copies the
string into it.  If successful, A pointer to the buffer is placed in
.IR *_buffer .
The caller must free the buffer.
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.SH RETURN VALUE
On success
.BR keyctl_get_security ()
returns the amount of data placed into the buffer.  If the buffer was too
small, then the size of buffer required will be returned, but no data will be
transferred.  On error, the value
.B -1
will be returned and errno will have been set to an appropriate error.
.P
On success
.BR keyctl_get_security_alloc ()
returns the amount of data in the buffer, less the NUL terminator.  On error, the value
.B -1
will be returned and errno will have been set to an appropriate error.
.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.SH ERRORS
.TP
.B ENOKEY
The key specified is invalid.
.TP
.B EKEYEXPIRED
The key specified has expired.
.TP
.B EKEYREVOKED
The key specified had been revoked.
.TP
.B EACCES
The key exists, but is not
.B viewable
by the calling process.
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.SH LINKING
This is a library function that can be found in
.IR libkeyutils .
When linking,
.B -lkeyutils
should be specified to the linker.
.\"""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""""
.SH SEE ALSO
.BR keyctl (1),
.br
.BR add_key (2),
.br
.BR keyctl (2),
.br
.BR request_key (2),
.br
.BR keyctl (3),
.br
.BR request-key (8)