1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3 * Copyright (C) 2019 Microsoft Corporation
4 *
5 * Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com)
6 *
7 * File: ima_asymmetric_keys.c
8 * Defines an IMA hook to measure asymmetric keys on key
9 * create or update.
10 */
11
12 #include <keys/asymmetric-type.h>
13 #include "ima.h"
14
15 /**
16 * ima_post_key_create_or_update - measure asymmetric keys
17 * @keyring: keyring to which the key is linked to
18 * @key: created or updated key
19 * @payload: The data used to instantiate or update the key.
20 * @payload_len: The length of @payload.
21 * @flags: key flags
22 * @create: flag indicating whether the key was created or updated
23 *
24 * Keys can only be measured, not appraised.
25 * The payload data used to instantiate or update the key is measured.
26 */
ima_post_key_create_or_update(struct key * keyring,struct key * key,const void * payload,size_t payload_len,unsigned long flags,bool create)27 void ima_post_key_create_or_update(struct key *keyring, struct key *key,
28 const void *payload, size_t payload_len,
29 unsigned long flags, bool create)
30 {
31 bool queued = false;
32
33 /* Only asymmetric keys are handled by this hook. */
34 if (key->type != &key_type_asymmetric)
35 return;
36
37 if (!payload || (payload_len == 0))
38 return;
39
40 if (ima_should_queue_key())
41 queued = ima_queue_key(keyring, payload, payload_len);
42
43 if (queued)
44 return;
45
46 /*
47 * keyring->description points to the name of the keyring
48 * (such as ".builtin_trusted_keys", ".ima", etc.) to
49 * which the given key is linked to.
50 *
51 * The name of the keyring is passed in the "eventname"
52 * parameter to process_buffer_measurement() and is set
53 * in the "eventname" field in ima_event_data for
54 * the key measurement IMA event.
55 *
56 * The name of the keyring is also passed in the "keyring"
57 * parameter to process_buffer_measurement() to check
58 * if the IMA policy is configured to measure a key linked
59 * to the given keyring.
60 */
61 process_buffer_measurement(NULL, payload, payload_len,
62 keyring->description, KEY_CHECK, 0,
63 keyring->description);
64 }
65