9f81a2eda4
Measuring keys requires a custom IMA policy to be loaded. Keys created or updated before a custom IMA policy is loaded should be queued and will be processed after a custom policy is loaded. This patch defines a workqueue for queuing keys when a custom IMA policy has not yet been loaded. An intermediate Kconfig boolean option namely IMA_QUEUE_EARLY_BOOT_KEYS is used to declare the workqueue functions. A flag namely ima_process_keys is used to check if the key should be queued or should be processed immediately. Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
137 lines
2.9 KiB
C
137 lines
2.9 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Copyright (C) 2019 Microsoft Corporation
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*
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* Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com)
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*
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* File: ima_queue_keys.c
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* Enables deferred processing of keys
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <keys/asymmetric-type.h>
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#include "ima.h"
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/*
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* Flag to indicate whether a key can be processed
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* right away or should be queued for processing later.
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*/
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static bool ima_process_keys;
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/*
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* To synchronize access to the list of keys that need to be measured
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*/
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static DEFINE_MUTEX(ima_keys_lock);
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static LIST_HEAD(ima_keys);
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static void ima_free_key_entry(struct ima_key_entry *entry)
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{
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if (entry) {
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kfree(entry->payload);
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kfree(entry->keyring_name);
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kfree(entry);
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}
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}
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static struct ima_key_entry *ima_alloc_key_entry(struct key *keyring,
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const void *payload,
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size_t payload_len)
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{
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int rc = 0;
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struct ima_key_entry *entry;
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entry = kzalloc(sizeof(*entry), GFP_KERNEL);
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if (entry) {
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entry->payload = kmemdup(payload, payload_len, GFP_KERNEL);
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entry->keyring_name = kstrdup(keyring->description,
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GFP_KERNEL);
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entry->payload_len = payload_len;
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}
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if ((entry == NULL) || (entry->payload == NULL) ||
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(entry->keyring_name == NULL)) {
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rc = -ENOMEM;
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goto out;
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}
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INIT_LIST_HEAD(&entry->list);
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out:
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if (rc) {
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ima_free_key_entry(entry);
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entry = NULL;
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}
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return entry;
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}
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bool ima_queue_key(struct key *keyring, const void *payload,
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size_t payload_len)
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{
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bool queued = false;
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struct ima_key_entry *entry;
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entry = ima_alloc_key_entry(keyring, payload, payload_len);
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if (!entry)
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return false;
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mutex_lock(&ima_keys_lock);
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if (!ima_process_keys) {
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list_add_tail(&entry->list, &ima_keys);
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queued = true;
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}
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mutex_unlock(&ima_keys_lock);
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if (!queued)
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ima_free_key_entry(entry);
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return queued;
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}
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/*
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* ima_process_queued_keys() - process keys queued for measurement
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*
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* This function sets ima_process_keys to true and processes queued keys.
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* From here on keys will be processed right away (not queued).
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*/
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void ima_process_queued_keys(void)
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{
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struct ima_key_entry *entry, *tmp;
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bool process = false;
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if (ima_process_keys)
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return;
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/*
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* Since ima_process_keys is set to true, any new key will be
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* processed immediately and not be queued to ima_keys list.
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* First one setting the ima_process_keys flag to true will
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* process the queued keys.
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*/
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mutex_lock(&ima_keys_lock);
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if (!ima_process_keys) {
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ima_process_keys = true;
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process = true;
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}
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mutex_unlock(&ima_keys_lock);
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if (!process)
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return;
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list_for_each_entry_safe(entry, tmp, &ima_keys, list) {
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process_buffer_measurement(entry->payload,
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entry->payload_len,
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entry->keyring_name,
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KEY_CHECK, 0,
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entry->keyring_name);
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list_del(&entry->list);
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ima_free_key_entry(entry);
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}
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}
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inline bool ima_should_queue_key(void)
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{
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return !ima_process_keys;
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}
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