mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-26 19:00:25 +00:00
![Tyler Hicks](/assets/img/avatar_default.png)
Take the properties of the kexec kernel's inode and the current task ownership into consideration when matching a KEXEC_CMDLINE operation to the rules in the IMA policy. This allows for some uniformity when writing IMA policy rules for KEXEC_KERNEL_CHECK, KEXEC_INITRAMFS_CHECK, and KEXEC_CMDLINE operations. Prior to this patch, it was not possible to write a set of rules like this: dont_measure func=KEXEC_KERNEL_CHECK obj_type=foo_t dont_measure func=KEXEC_INITRAMFS_CHECK obj_type=foo_t dont_measure func=KEXEC_CMDLINE obj_type=foo_t measure func=KEXEC_KERNEL_CHECK measure func=KEXEC_INITRAMFS_CHECK measure func=KEXEC_CMDLINE The inode information associated with the kernel being loaded by a kexec_kernel_load(2) syscall can now be included in the decision to measure or not Additonally, the uid, euid, and subj_* conditionals can also now be used in KEXEC_CMDLINE rules. There was no technical reason as to why those conditionals weren't being considered previously other than ima_match_rules() didn't have a valid inode to use so it immediately bailed out for KEXEC_CMDLINE operations rather than going through the full list of conditional comparisons. Signed-off-by: Tyler Hicks <tyhicks@linux.microsoft.com> Cc: Eric Biederman <ebiederm@xmission.com> Cc: kexec@lists.infradead.org Reviewed-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com> Signed-off-by: Mimi Zohar <zohar@linux.ibm.com>
174 lines
3.9 KiB
C
174 lines
3.9 KiB
C
// SPDX-License-Identifier: GPL-2.0+
|
|
/*
|
|
* Copyright (C) 2019 Microsoft Corporation
|
|
*
|
|
* Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com)
|
|
*
|
|
* File: ima_queue_keys.c
|
|
* Enables deferred processing of keys
|
|
*/
|
|
|
|
#include <linux/workqueue.h>
|
|
#include <keys/asymmetric-type.h>
|
|
#include "ima.h"
|
|
|
|
/*
|
|
* Flag to indicate whether a key can be processed
|
|
* right away or should be queued for processing later.
|
|
*/
|
|
static bool ima_process_keys;
|
|
|
|
/*
|
|
* To synchronize access to the list of keys that need to be measured
|
|
*/
|
|
static DEFINE_MUTEX(ima_keys_lock);
|
|
static LIST_HEAD(ima_keys);
|
|
|
|
/*
|
|
* If custom IMA policy is not loaded then keys queued up
|
|
* for measurement should be freed. This worker is used
|
|
* for handling this scenario.
|
|
*/
|
|
static long ima_key_queue_timeout = 300000; /* 5 Minutes */
|
|
static void ima_keys_handler(struct work_struct *work);
|
|
static DECLARE_DELAYED_WORK(ima_keys_delayed_work, ima_keys_handler);
|
|
static bool timer_expired;
|
|
|
|
/*
|
|
* This worker function frees keys that may still be
|
|
* queued up in case custom IMA policy was not loaded.
|
|
*/
|
|
static void ima_keys_handler(struct work_struct *work)
|
|
{
|
|
timer_expired = true;
|
|
ima_process_queued_keys();
|
|
}
|
|
|
|
/*
|
|
* This function sets up a worker to free queued keys in case
|
|
* custom IMA policy was never loaded.
|
|
*/
|
|
void ima_init_key_queue(void)
|
|
{
|
|
schedule_delayed_work(&ima_keys_delayed_work,
|
|
msecs_to_jiffies(ima_key_queue_timeout));
|
|
}
|
|
|
|
static void ima_free_key_entry(struct ima_key_entry *entry)
|
|
{
|
|
if (entry) {
|
|
kfree(entry->payload);
|
|
kfree(entry->keyring_name);
|
|
kfree(entry);
|
|
}
|
|
}
|
|
|
|
static struct ima_key_entry *ima_alloc_key_entry(struct key *keyring,
|
|
const void *payload,
|
|
size_t payload_len)
|
|
{
|
|
int rc = 0;
|
|
const char *audit_cause = "ENOMEM";
|
|
struct ima_key_entry *entry;
|
|
|
|
entry = kzalloc(sizeof(*entry), GFP_KERNEL);
|
|
if (entry) {
|
|
entry->payload = kmemdup(payload, payload_len, GFP_KERNEL);
|
|
entry->keyring_name = kstrdup(keyring->description,
|
|
GFP_KERNEL);
|
|
entry->payload_len = payload_len;
|
|
}
|
|
|
|
if ((entry == NULL) || (entry->payload == NULL) ||
|
|
(entry->keyring_name == NULL)) {
|
|
rc = -ENOMEM;
|
|
goto out;
|
|
}
|
|
|
|
INIT_LIST_HEAD(&entry->list);
|
|
|
|
out:
|
|
if (rc) {
|
|
integrity_audit_message(AUDIT_INTEGRITY_PCR, NULL,
|
|
keyring->description,
|
|
func_measure_str(KEY_CHECK),
|
|
audit_cause, rc, 0, rc);
|
|
ima_free_key_entry(entry);
|
|
entry = NULL;
|
|
}
|
|
|
|
return entry;
|
|
}
|
|
|
|
bool ima_queue_key(struct key *keyring, const void *payload,
|
|
size_t payload_len)
|
|
{
|
|
bool queued = false;
|
|
struct ima_key_entry *entry;
|
|
|
|
entry = ima_alloc_key_entry(keyring, payload, payload_len);
|
|
if (!entry)
|
|
return false;
|
|
|
|
mutex_lock(&ima_keys_lock);
|
|
if (!ima_process_keys) {
|
|
list_add_tail(&entry->list, &ima_keys);
|
|
queued = true;
|
|
}
|
|
mutex_unlock(&ima_keys_lock);
|
|
|
|
if (!queued)
|
|
ima_free_key_entry(entry);
|
|
|
|
return queued;
|
|
}
|
|
|
|
/*
|
|
* ima_process_queued_keys() - process keys queued for measurement
|
|
*
|
|
* This function sets ima_process_keys to true and processes queued keys.
|
|
* From here on keys will be processed right away (not queued).
|
|
*/
|
|
void ima_process_queued_keys(void)
|
|
{
|
|
struct ima_key_entry *entry, *tmp;
|
|
bool process = false;
|
|
|
|
if (ima_process_keys)
|
|
return;
|
|
|
|
/*
|
|
* Since ima_process_keys is set to true, any new key will be
|
|
* processed immediately and not be queued to ima_keys list.
|
|
* First one setting the ima_process_keys flag to true will
|
|
* process the queued keys.
|
|
*/
|
|
mutex_lock(&ima_keys_lock);
|
|
if (!ima_process_keys) {
|
|
ima_process_keys = true;
|
|
process = true;
|
|
}
|
|
mutex_unlock(&ima_keys_lock);
|
|
|
|
if (!process)
|
|
return;
|
|
|
|
if (!timer_expired)
|
|
cancel_delayed_work_sync(&ima_keys_delayed_work);
|
|
|
|
list_for_each_entry_safe(entry, tmp, &ima_keys, list) {
|
|
if (!timer_expired)
|
|
process_buffer_measurement(NULL, entry->payload,
|
|
entry->payload_len,
|
|
entry->keyring_name,
|
|
KEY_CHECK, 0,
|
|
entry->keyring_name);
|
|
list_del(&entry->list);
|
|
ima_free_key_entry(entry);
|
|
}
|
|
}
|
|
|
|
inline bool ima_should_queue_key(void)
|
|
{
|
|
return !ima_process_keys;
|
|
}
|