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// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2019 Microsoft Corporation
*
* Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com)
*
* File: ima_asymmetric_keys.c
* Defines an IMA hook to measure asymmetric keys on key
* create or update.
*/
#include <keys/asymmetric-type.h>
#include <linux/user_namespace.h>
#include <linux/ima.h>
#include "ima.h"
/**
* ima_post_key_create_or_update - measure asymmetric keys
* @keyring: keyring to which the key is linked to
* @key: created or updated key
* @payload: The data used to instantiate or update the key.
* @payload_len: The length of @payload.
* @flags: key flags
* @create: flag indicating whether the key was created or updated
*
* Keys can only be measured, not appraised.
* The payload data used to instantiate or update the key is measured.
*/
void ima_post_key_create_or_update(struct key *keyring, struct key *key,
const void *payload, size_t payload_len,
unsigned long flags, bool create)
{
bool queued = false;
/* Only asymmetric keys are handled by this hook. */
if (key->type != &key_type_asymmetric)
return;
if (!payload || (payload_len == 0))
return;
if (ima_should_queue_key())
queued = ima_queue_key(keyring, payload, payload_len);
if (queued)
return;
/*
* keyring->description points to the name of the keyring
* (such as ".builtin_trusted_keys", ".ima", etc.) to
* which the given key is linked to.
*
* The name of the keyring is passed in the "eventname"
* parameter to process_buffer_measurement() and is set
* in the "eventname" field in ima_event_data for
* the key measurement IMA event.
*
* The name of the keyring is also passed in the "keyring"
* parameter to process_buffer_measurement() to check
* if the IMA policy is configured to measure a key linked
* to the given keyring.
*/
process_buffer_measurement(&init_user_ns, NULL, payload, payload_len,
keyring->description, KEY_CHECK, 0,
keyring->description, false, NULL, 0);
}
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