126 lines
2.9 KiB
C
126 lines
2.9 KiB
C
|
// SPDX-License-Identifier: GPL-2.0+
|
||
|
|
/*
|
||
|
|
* Copyright (C) 2021 Microsoft Corporation
|
||
|
|
*
|
||
|
|
* Author: Lakshmi Ramasubramanian (nramas@linux.microsoft.com)
|
||
|
|
*
|
||
|
|
* Measure critical data structures maintainted by SELinux
|
||
|
|
* using IMA subsystem.
|
||
|
|
*/
|
||
|
|
#include <linux/vmalloc.h>
|
||
|
|
#include <linux/ima.h>
|
||
|
|
#include "security.h"
|
||
|
|
#include "ima.h"
|
||
|
|
|
||
|
|
/*
|
||
|
|
* selinux_ima_collect_state - Read selinux configuration settings
|
||
|
|
*
|
||
|
|
* @state: selinux_state
|
||
|
|
*
|
||
|
|
* On success returns the configuration settings string.
|
||
|
|
* On error, returns NULL.
|
||
|
|
*/
|
||
|
|
static char *selinux_ima_collect_state(struct selinux_state *state)
|
||
|
|
{
|
||
|
|
const char *on = "=1;", *off = "=0;";
|
||
|
|
char *buf;
|
||
|
|
int buf_len, len, i, rc;
|
||
|
|
|
||
|
|
buf_len = strlen("initialized=0;enforcing=0;checkreqprot=0;") + 1;
|
||
|
|
|
||
|
|
len = strlen(on);
|
||
|
|
for (i = 0; i < __POLICYDB_CAP_MAX; i++)
|
||
|
|
buf_len += strlen(selinux_policycap_names[i]) + len;
|
||
|
|
|
||
|
|
buf = kzalloc(buf_len, GFP_KERNEL);
|
||
|
|
if (!buf)
|
||
|
|
return NULL;
|
||
|
|
|
||
|
|
rc = strscpy(buf, "initialized", buf_len);
|
||
|
|
WARN_ON(rc < 0);
|
||
|
|
|
||
|
|
rc = strlcat(buf, selinux_initialized(state) ? on : off, buf_len);
|
||
|
|
WARN_ON(rc >= buf_len);
|
||
|
|
|
||
|
|
rc = strlcat(buf, "enforcing", buf_len);
|
||
|
|
WARN_ON(rc >= buf_len);
|
||
|
|
|
||
|
|
rc = strlcat(buf, enforcing_enabled(state) ? on : off, buf_len);
|
||
|
|
WARN_ON(rc >= buf_len);
|
||
|
|
|
||
|
|
rc = strlcat(buf, "checkreqprot", buf_len);
|
||
|
|
WARN_ON(rc >= buf_len);
|
||
|
|
|
||
|
|
rc = strlcat(buf, checkreqprot_get(state) ? on : off, buf_len);
|
||
|
|
WARN_ON(rc >= buf_len);
|
||
|
|
|
||
|
|
for (i = 0; i < __POLICYDB_CAP_MAX; i++) {
|
||
|
|
rc = strlcat(buf, selinux_policycap_names[i], buf_len);
|
||
|
|
WARN_ON(rc >= buf_len);
|
||
|
|
|
||
|
|
rc = strlcat(buf, state->policycap[i] ? on : off, buf_len);
|
||
|
|
WARN_ON(rc >= buf_len);
|
||
|
|
}
|
||
|
|
|
||
|
|
return buf;
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* selinux_ima_measure_state_locked - Measure SELinux state and hash of policy
|
||
|
|
*
|
||
|
|
* @state: selinux state struct
|
||
|
|
*/
|
||
|
|
void selinux_ima_measure_state_locked(struct selinux_state *state)
|
||
|
|
{
|
||
|
|
char *state_str = NULL;
|
||
|
|
void *policy = NULL;
|
||
|
|
size_t policy_len;
|
||
|
|
int rc = 0;
|
||
|
|
|
||
|
|
lockdep_assert_held(&state->policy_mutex);
|
||
|
|
|
||
|
|
state_str = selinux_ima_collect_state(state);
|
||
|
|
if (!state_str) {
|
||
|
|
pr_err("SELinux: %s: failed to read state.\n", __func__);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
ima_measure_critical_data("selinux", "selinux-state",
|
||
|
|
state_str, strlen(state_str), false,
|
||
|
|
NULL, 0);
|
||
|
|
|
||
|
|
kfree(state_str);
|
||
|
|
|
||
|
|
/*
|
||
|
|
* Measure SELinux policy only after initialization is completed.
|
||
|
|
*/
|
||
|
|
if (!selinux_initialized(state))
|
||
|
|
return;
|
||
|
|
|
||
|
|
rc = security_read_state_kernel(state, &policy, &policy_len);
|
||
|
|
if (rc) {
|
||
|
|
pr_err("SELinux: %s: failed to read policy %d.\n", __func__, rc);
|
||
|
|
return;
|
||
|
|
}
|
||
|
|
|
||
|
|
ima_measure_critical_data("selinux", "selinux-policy-hash",
|
||
|
|
policy, policy_len, true,
|
||
|
|
NULL, 0);
|
||
|
|
|
||
|
|
vfree(policy);
|
||
|
|
}
|
||
|
|
|
||
|
|
/*
|
||
|
|
* selinux_ima_measure_state - Measure SELinux state and hash of policy
|
||
|
|
*
|
||
|
|
* @state: selinux state struct
|
||
|
|
*/
|
||
|
|
void selinux_ima_measure_state(struct selinux_state *state)
|
||
|
|
{
|
||
|
|
lockdep_assert_not_held(&state->policy_mutex);
|
||
|
|
|
||
|
|
mutex_lock(&state->policy_mutex);
|
||
|
|
selinux_ima_measure_state_locked(state);
|
||
|
|
mutex_unlock(&state->policy_mutex);
|
||
|
|
}
|