LXR linux/security/integrity/ima/ima_asymmetric

   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 <linux/ima.h>
  15#include "ima.h"
  16
  17/**
  18 * ima_post_key_create_or_update - measure asymmetric keys
  19 * @keyring: keyring to which the key is linked to
  20 * @key: created or updated key
  21 * @payload: The data used to instantiate or update the key.
  22 * @payload_len: The length of @payload.
  23 * @flags: key flags
  24 * @create: flag indicating whether the key was created or updated
  25 *
  26 * Keys can only be measured, not appraised.
  27 * The payload data used to instantiate or update the key is measured.
  28 */
  29void ima_post_key_create_or_update(struct key *keyring, struct key *key,
  30                                   const void *payload, size_t payload_len,
  31                                   unsigned long flags, bool create)
  32{
  33        bool queued = false;
  34
  35        /* Only asymmetric keys are handled by this hook. */
  36        if (key->type != &key_type_asymmetric)
  37                return;
  38
  39        if (!payload || (payload_len == 0))
  40                return;
  41
  42        if (ima_should_queue_key())
  43                queued = ima_queue_key(keyring, payload, payload_len);
  44
  45        if (queued)
  46                return;
  47
  48        /*
  49         * keyring->description points to the name of the keyring
  50         * (such as ".builtin_trusted_keys", ".ima", etc.) to
  51         * which the given key is linked to.
  52         *
  53         * The name of the keyring is passed in the "eventname"
  54         * parameter to process_buffer_measurement() and is set
  55         * in the "eventname" field in ima_event_data for
  56         * the key measurement IMA event.
  57         *
  58         * The name of the keyring is also passed in the "keyring"
  59         * parameter to process_buffer_measurement() to check
  60         * if the IMA policy is configured to measure a key linked
  61         * to the given keyring.
  62         */
  63        process_buffer_measurement(&init_user_ns, NULL, payload, payload_len,
  64                                   keyring->description, KEY_CHECK, 0,
  65                                   keyring->description, false);
  66}
  67