linux/security/integrity/ima/ima_asymmetric_keys.c
Roberto Sassu ca3c9bdb10 ima: Add digest and digest_len params to the functions to measure a buffer
This patch performs the final modification necessary to pass the buffer
measurement to callers, so that they provide a functionality similar to
ima_file_hash(). It adds the 'digest' and 'digest_len' parameters to
ima_measure_critical_data() and process_buffer_measurement().

These functions calculate the digest even if there is no suitable rule in
the IMA policy and, in this case, they simply return 1 before generating a
new measurement entry.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
2021-07-23 09:27:02 -04:00

67 lines
2.0 KiB
C

// 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);
}