NAME¶
avc_open, avc_destroy, avc_reset, avc_cleanup - userspace SELinux AVC setup and
teardown
SYNOPSIS¶
#include <selinux/selinux.h>
#include <selinux/avc.h>
int avc_open(struct selinux_opt *options, unsigned
nopt);
void avc_destroy(void);
int avc_reset(void);
void avc_cleanup(void);
DESCRIPTION¶
avc_open() initializes the userspace AVC and must be called before any
other AVC operation can be performed.
avc_destroy() destroys the userspace AVC, freeing all internal memory
structures. After this call has been made,
avc_open() must be called
again before any AVC operations can be performed.
avc_reset() flushes the userspace AVC, causing it to forget any cached
access decisions. The userspace AVC normally calls this function automatically
when needed, see
NETLINK NOTIFICATION below.
avc_cleanup() attempts to free unused memory within the userspace AVC,
but does not flush any cached access decisions. Under normal operation,
calling this function should not be necessary.
OPTIONS¶
The userspace AVC obeys callbacks set via
selinux_set_callback(3), in
particular the logging and audit callbacks.
The options which may be passed to
avc_open() include the following:
- AVC_OPT_SETENFORCE
- This option forces the userspace AVC into enforcing mode if the option
value is non-NULL; permissive mode otherwise. The system enforcing mode
will be ignored.
NETLINK NOTIFICATION¶
Beginning with version 2.6.4, the Linux kernel supports SELinux status change
notification via netlink. Two message types are currently implemented,
indicating changes to the enforcing mode and to the loaded policy in the
kernel, respectively. The userspace AVC listens for these messages and takes
the appropriate action, modifying the behavior of
avc_has_perm(3) to
reflect the current enforcing mode and flushing the cache on receipt of a
policy load notification. Audit messages are produced when netlink
notifications are processed.
RETURN VALUE¶
Functions with a return value return zero on success. On error, -1 is returned
and
errno is set appropriately.
AUTHOR¶
Eamon Walsh <ewalsh@tycho.nsa.gov>
SEE ALSO¶
selinux(8),
avc_has_perm(3),
avc_context_to_sid(3),
avc_cache_stats(3),
avc_add_callback(3),
selinux_set_callback(3),
security_compute_av(3)