// 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(&nop_mnt_idmap, NULL, payload, payload_len,
                                   keyring->description, KEY_CHECK, 0,
                                   keyring->description, false, NULL, 0);
}