linux/include
David Howells f7e47677e3 watch_queue: Add a key/keyring notification facility
Add a key/keyring change notification facility whereby notifications about
changes in key and keyring content and attributes can be received.

Firstly, an event queue needs to be created:

	pipe2(fds, O_NOTIFICATION_PIPE);
	ioctl(fds[1], IOC_WATCH_QUEUE_SET_SIZE, 256);

then a notification can be set up to report notifications via that queue:

	struct watch_notification_filter filter = {
		.nr_filters = 1,
		.filters = {
			[0] = {
				.type = WATCH_TYPE_KEY_NOTIFY,
				.subtype_filter[0] = UINT_MAX,
			},
		},
	};
	ioctl(fds[1], IOC_WATCH_QUEUE_SET_FILTER, &filter);
	keyctl_watch_key(KEY_SPEC_SESSION_KEYRING, fds[1], 0x01);

After that, records will be placed into the queue when events occur in
which keys are changed in some way.  Records are of the following format:

	struct key_notification {
		struct watch_notification watch;
		__u32	key_id;
		__u32	aux;
	} *n;

Where:

	n->watch.type will be WATCH_TYPE_KEY_NOTIFY.

	n->watch.subtype will indicate the type of event, such as
	NOTIFY_KEY_REVOKED.

	n->watch.info & WATCH_INFO_LENGTH will indicate the length of the
	record.

	n->watch.info & WATCH_INFO_ID will be the second argument to
	keyctl_watch_key(), shifted.

	n->key will be the ID of the affected key.

	n->aux will hold subtype-dependent information, such as the key
	being linked into the keyring specified by n->key in the case of
	NOTIFY_KEY_LINKED.

Note that it is permissible for event records to be of variable length -
or, at least, the length may be dependent on the subtype.  Note also that
the queue can be shared between multiple notifications of various types.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
2020-05-19 15:19:06 +01:00
..
acpi Additional ACPI updates for 5.7-rc1 2020-04-06 10:35:06 -07:00
asm-generic arch: split MODULE_ARCH_VERMAGIC definitions out to <asm/vermagic.h> 2020-04-23 10:50:26 +09:00
clocksource
crypto crypto: curve25519 - do not pollute dispatcher based on assembler 2020-04-09 00:01:59 +09:00
drm drm: fix trivial field description cut-and-paste error 2020-05-11 10:48:53 -07:00
dt-bindings RISC-V Patches for the 5.7 Merge Window, Part 1 2020-04-09 10:51:30 -07:00
keys
kunit
kvm
linux watch_queue: Add a key/keyring notification facility 2020-05-19 15:19:06 +01:00
math-emu
media
misc
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf 2020-05-14 13:15:02 -07:00
pcmcia
ras
rdma
scsi SCSI misc on 20200402 2020-04-02 17:03:53 -07:00
soc net: dsa: ocelot: the MAC table on Felix is twice as large 2020-05-06 17:15:24 -07:00
sound ALSA: rawmidi: Fix racy buffer resize under concurrent accesses 2020-05-07 22:29:14 +02:00
target
trace block-5.7-2020-05-09 2020-05-10 11:16:07 -07:00
uapi watch_queue: Add a key/keyring notification facility 2020-05-19 15:19:06 +01:00
vdso vdso/datapage: Use correct clock mode name in comment 2020-04-20 19:19:52 +02:00
video
xen xen: Use evtchn_type_t as a type for event channels 2020-04-07 12:12:54 +02:00