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