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 <linux/user_namespace.h> 14 #include "ima.h" 15 16 /** 17 * ima_post_key_create_or_update - measure asymmetric keys 18 * @keyring: keyring to which the key is linked to 19 * @key: created or updated key 20 * @payload: The data used to instantiate or update the key. 21 * @payload_len: The length of @payload. 22 * @flags: key flags 23 * @create: flag indicating whether the key was created or updated 24 * 25 * Keys can only be measured, not appraised. 26 * The payload data used to instantiate or update the key is measured. 27 */ 28 void ima_post_key_create_or_update(struct key *keyring, struct key *key, 29 const void *payload, size_t payload_len, 30 unsigned long flags, bool create) 31 { 32 bool queued = false; 33 34 /* Only asymmetric keys are handled by this hook. */ 35 if (key->type != &key_type_asymmetric) 36 return; 37 38 if (!payload || (payload_len == 0)) 39 return; 40 41 if (ima_should_queue_key()) 42 queued = ima_queue_key(keyring, payload, payload_len); 43 44 if (queued) 45 return; 46 47 /* 48 * keyring->description points to the name of the keyring 49 * (such as ".builtin_trusted_keys", ".ima", etc.) to 50 * which the given key is linked to. 51 * 52 * The name of the keyring is passed in the "eventname" 53 * parameter to process_buffer_measurement() and is set 54 * in the "eventname" field in ima_event_data for 55 * the key measurement IMA event. 56 * 57 * The name of the keyring is also passed in the "keyring" 58 * parameter to process_buffer_measurement() to check 59 * if the IMA policy is configured to measure a key linked 60 * to the given keyring. 61 */ 62 process_buffer_measurement(&init_user_ns, NULL, payload, payload_len, 63 keyring->description, KEY_CHECK, 0, 64 keyring->description, false); 65 } 66