selinuxfs.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/* Updated: Karl MacMillan <kmacmillan@tresys.com>
   3 *
   4 *	Added conditional policy language extensions
   5 *
   6 *  Updated: Hewlett-Packard <paul@paul-moore.com>
   7 *
   8 *	Added support for the policy capability bitmap
   9 *
  10 * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
  11 * Copyright (C) 2003 - 2004 Tresys Technology, LLC
  12 * Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
  13 */
  14
  15#include <linux/kernel.h>
  16#include <linux/pagemap.h>
  17#include <linux/slab.h>
  18#include <linux/vmalloc.h>
  19#include <linux/fs.h>
  20#include <linux/fs_context.h>
  21#include <linux/mount.h>
  22#include <linux/mutex.h>
  23#include <linux/namei.h>
  24#include <linux/init.h>
  25#include <linux/string.h>
  26#include <linux/security.h>
  27#include <linux/major.h>
  28#include <linux/seq_file.h>
  29#include <linux/percpu.h>
  30#include <linux/audit.h>
  31#include <linux/uaccess.h>
  32#include <linux/kobject.h>
  33#include <linux/ctype.h>
  34
  35/* selinuxfs pseudo filesystem for exporting the security policy API.
  36   Based on the proc code and the fs/nfsd/nfsctl.c code. */
  37
  38#include "initcalls.h"
  39#include "flask.h"
  40#include "avc.h"
  41#include "avc_ss.h"
  42#include "security.h"
  43#include "objsec.h"
  44#include "conditional.h"
  45#include "ima.h"
  46
  47enum sel_inos {
  48	SEL_ROOT_INO = 2,
  49	SEL_LOAD,	/* load policy */
  50	SEL_ENFORCE,	/* get or set enforcing status */
  51	SEL_CONTEXT,	/* validate context */
  52	SEL_ACCESS,	/* compute access decision */
  53	SEL_CREATE,	/* compute create labeling decision */
  54	SEL_RELABEL,	/* compute relabeling decision */
  55	SEL_USER,	/* compute reachable user contexts */
  56	SEL_POLICYVERS,	/* return policy version for this kernel */
  57	SEL_COMMIT_BOOLS, /* commit new boolean values */
  58	SEL_MLS,	/* return if MLS policy is enabled */
  59	SEL_DISABLE,	/* disable SELinux until next reboot */
  60	SEL_MEMBER,	/* compute polyinstantiation membership decision */
  61	SEL_CHECKREQPROT, /* check requested protection, not kernel-applied one */
  62	SEL_COMPAT_NET,	/* whether to use old compat network packet controls */
  63	SEL_REJECT_UNKNOWN, /* export unknown reject handling to userspace */
  64	SEL_DENY_UNKNOWN, /* export unknown deny handling to userspace */
  65	SEL_STATUS,	/* export current status using mmap() */
  66	SEL_POLICY,	/* allow userspace to read the in kernel policy */
  67	SEL_VALIDATE_TRANS, /* compute validatetrans decision */
  68	SEL_INO_NEXT,	/* The next inode number to use */
  69};
  70
  71struct selinux_fs_info {
  72	struct dentry *bool_dir;
  73	unsigned int bool_num;
  74	char **bool_pending_names;
  75	int *bool_pending_values;
  76	struct dentry *class_dir;
  77	unsigned long last_class_ino;
  78	bool policy_opened;
  79	unsigned long last_ino;
  80	struct super_block *sb;
  81};
  82
  83static int selinux_fs_info_create(struct super_block *sb)
  84{
  85	struct selinux_fs_info *fsi;
  86
  87	fsi = kzalloc(sizeof(*fsi), GFP_KERNEL);
  88	if (!fsi)
  89		return -ENOMEM;
  90
  91	fsi->last_ino = SEL_INO_NEXT - 1;
  92	fsi->sb = sb;
  93	sb->s_fs_info = fsi;
  94	return 0;
  95}
  96
  97static void selinux_fs_info_free(struct super_block *sb)
  98{
  99	struct selinux_fs_info *fsi = sb->s_fs_info;
 100	unsigned int i;
 101
 102	if (fsi) {
 103		for (i = 0; i < fsi->bool_num; i++)
 104			kfree(fsi->bool_pending_names[i]);
 105		kfree(fsi->bool_pending_names);
 106		kfree(fsi->bool_pending_values);
 107	}
 108	kfree(sb->s_fs_info);
 109	sb->s_fs_info = NULL;
 110}
 111
 112#define SEL_INITCON_INO_OFFSET		0x01000000
 113#define SEL_BOOL_INO_OFFSET		0x02000000
 114#define SEL_CLASS_INO_OFFSET		0x04000000
 115#define SEL_POLICYCAP_INO_OFFSET	0x08000000
 116#define SEL_INO_MASK			0x00ffffff
 117
 118#define BOOL_DIR_NAME "booleans"
 119#define CLASS_DIR_NAME "class"
 120
 121#define TMPBUFLEN	12
 122static ssize_t sel_read_enforce(struct file *filp, char __user *buf,
 123				size_t count, loff_t *ppos)
 124{
 125	char tmpbuf[TMPBUFLEN];
 126	ssize_t length;
 127
 128	length = scnprintf(tmpbuf, TMPBUFLEN, "%d",
 129			   enforcing_enabled());
 130	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 131}
 132
 133#ifdef CONFIG_SECURITY_SELINUX_DEVELOP
 134static ssize_t sel_write_enforce(struct file *file, const char __user *buf,
 135				 size_t count, loff_t *ppos)
 136
 137{
 138	char *page = NULL;
 139	ssize_t length;
 140	int scan_value;
 141	bool old_value, new_value;
 142
 143	if (count >= PAGE_SIZE)
 144		return -ENOMEM;
 145
 146	/* No partial writes. */
 147	if (*ppos != 0)
 148		return -EINVAL;
 149
 150	page = memdup_user_nul(buf, count);
 151	if (IS_ERR(page))
 152		return PTR_ERR(page);
 153
 154	length = -EINVAL;
 155	if (sscanf(page, "%d", &scan_value) != 1)
 156		goto out;
 157
 158	new_value = !!scan_value;
 159
 160	old_value = enforcing_enabled();
 161	if (new_value != old_value) {
 162		length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 163				      SECCLASS_SECURITY, SECURITY__SETENFORCE,
 164				      NULL);
 165		if (length)
 166			goto out;
 167		audit_log(audit_context(), GFP_KERNEL, AUDIT_MAC_STATUS,
 168			"enforcing=%d old_enforcing=%d auid=%u ses=%u"
 169			" enabled=1 old-enabled=1 lsm=selinux res=1",
 170			new_value, old_value,
 171			from_kuid(&init_user_ns, audit_get_loginuid(current)),
 172			audit_get_sessionid(current));
 173		enforcing_set(new_value);
 174		if (new_value)
 175			avc_ss_reset(0);
 176		selnl_notify_setenforce(new_value);
 177		selinux_status_update_setenforce(new_value);
 178		if (!new_value)
 179			call_blocking_lsm_notifier(LSM_POLICY_CHANGE, NULL);
 180
 181		selinux_ima_measure_state();
 182	}
 183	length = count;
 184out:
 185	kfree(page);
 186	return length;
 187}
 188#else
 189#define sel_write_enforce NULL
 190#endif
 191
 192static const struct file_operations sel_enforce_ops = {
 193	.read		= sel_read_enforce,
 194	.write		= sel_write_enforce,
 195	.llseek		= generic_file_llseek,
 196};
 197
 198static ssize_t sel_read_handle_unknown(struct file *filp, char __user *buf,
 199					size_t count, loff_t *ppos)
 200{
 201	char tmpbuf[TMPBUFLEN];
 202	ssize_t length;
 203	ino_t ino = file_inode(filp)->i_ino;
 204	int handle_unknown = (ino == SEL_REJECT_UNKNOWN) ?
 205		security_get_reject_unknown() :
 206		!security_get_allow_unknown();
 207
 208	length = scnprintf(tmpbuf, TMPBUFLEN, "%d", handle_unknown);
 209	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 210}
 211
 212static const struct file_operations sel_handle_unknown_ops = {
 213	.read		= sel_read_handle_unknown,
 214	.llseek		= generic_file_llseek,
 215};
 216
 217static int sel_open_handle_status(struct inode *inode, struct file *filp)
 218{
 219	struct page    *status = selinux_kernel_status_page();
 220
 221	if (!status)
 222		return -ENOMEM;
 223
 224	filp->private_data = status;
 225
 226	return 0;
 227}
 228
 229static ssize_t sel_read_handle_status(struct file *filp, char __user *buf,
 230				      size_t count, loff_t *ppos)
 231{
 232	struct page    *status = filp->private_data;
 233
 234	BUG_ON(!status);
 235
 236	return simple_read_from_buffer(buf, count, ppos,
 237				       page_address(status),
 238				       sizeof(struct selinux_kernel_status));
 239}
 240
 241static int sel_mmap_handle_status(struct file *filp,
 242				  struct vm_area_struct *vma)
 243{
 244	struct page    *status = filp->private_data;
 245	unsigned long	size = vma->vm_end - vma->vm_start;
 246
 247	BUG_ON(!status);
 248
 249	/* only allows one page from the head */
 250	if (vma->vm_pgoff > 0 || size != PAGE_SIZE)
 251		return -EIO;
 252	/* disallow writable mapping */
 253	if (vma->vm_flags & VM_WRITE)
 254		return -EPERM;
 255	/* disallow mprotect() turns it into writable */
 256	vm_flags_clear(vma, VM_MAYWRITE);
 257
 258	return remap_pfn_range(vma, vma->vm_start,
 259			       page_to_pfn(status),
 260			       size, vma->vm_page_prot);
 261}
 262
 263static const struct file_operations sel_handle_status_ops = {
 264	.open		= sel_open_handle_status,
 265	.read		= sel_read_handle_status,
 266	.mmap		= sel_mmap_handle_status,
 267	.llseek		= generic_file_llseek,
 268};
 269
 270static ssize_t sel_write_disable(struct file *file, const char __user *buf,
 271				 size_t count, loff_t *ppos)
 272
 273{
 274	char *page;
 275	ssize_t length;
 276	int new_value;
 277
 278	if (count >= PAGE_SIZE)
 279		return -ENOMEM;
 280
 281	/* No partial writes. */
 282	if (*ppos != 0)
 283		return -EINVAL;
 284
 285	page = memdup_user_nul(buf, count);
 286	if (IS_ERR(page))
 287		return PTR_ERR(page);
 288
 289	if (sscanf(page, "%d", &new_value) != 1) {
 290		length = -EINVAL;
 291		goto out;
 292	}
 293	length = count;
 294
 295	if (new_value) {
 296		pr_err("SELinux: https://github.com/SELinuxProject/selinux-kernel/wiki/DEPRECATE-runtime-disable\n");
 297		pr_err("SELinux: Runtime disable is not supported, use selinux=0 on the kernel cmdline.\n");
 298	}
 299
 300out:
 301	kfree(page);
 302	return length;
 303}
 304
 305static const struct file_operations sel_disable_ops = {
 306	.write		= sel_write_disable,
 307	.llseek		= generic_file_llseek,
 308};
 309
 310static ssize_t sel_read_policyvers(struct file *filp, char __user *buf,
 311				   size_t count, loff_t *ppos)
 312{
 313	char tmpbuf[TMPBUFLEN];
 314	ssize_t length;
 315
 316	length = scnprintf(tmpbuf, TMPBUFLEN, "%u", POLICYDB_VERSION_MAX);
 317	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 318}
 319
 320static const struct file_operations sel_policyvers_ops = {
 321	.read		= sel_read_policyvers,
 322	.llseek		= generic_file_llseek,
 323};
 324
 325/* declaration for sel_write_load */
 326static int sel_make_bools(struct selinux_policy *newpolicy, struct dentry *bool_dir,
 327			  unsigned int *bool_num, char ***bool_pending_names,
 328			  int **bool_pending_values);
 329static int sel_make_classes(struct selinux_policy *newpolicy,
 330			    struct dentry *class_dir,
 331			    unsigned long *last_class_ino);
 332
 333/* declaration for sel_make_class_dirs */
 334static struct dentry *sel_make_dir(struct dentry *dir, const char *name,
 335			unsigned long *ino);
 336
 337/* declaration for sel_make_policy_nodes */
 338static struct dentry *sel_make_swapover_dir(struct super_block *sb,
 339						unsigned long *ino);
 340
 341static ssize_t sel_read_mls(struct file *filp, char __user *buf,
 342				size_t count, loff_t *ppos)
 343{
 344	char tmpbuf[TMPBUFLEN];
 345	ssize_t length;
 346
 347	length = scnprintf(tmpbuf, TMPBUFLEN, "%d",
 348			   security_mls_enabled());
 349	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 350}
 351
 352static const struct file_operations sel_mls_ops = {
 353	.read		= sel_read_mls,
 354	.llseek		= generic_file_llseek,
 355};
 356
 357struct policy_load_memory {
 358	size_t len;
 359	void *data;
 360};
 361
 362static int sel_open_policy(struct inode *inode, struct file *filp)
 363{
 364	struct selinux_fs_info *fsi = inode->i_sb->s_fs_info;
 365	struct policy_load_memory *plm = NULL;
 366	int rc;
 367
 368	BUG_ON(filp->private_data);
 369
 370	mutex_lock(&selinux_state.policy_mutex);
 371
 372	rc = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 373			  SECCLASS_SECURITY, SECURITY__READ_POLICY, NULL);
 374	if (rc)
 375		goto err;
 376
 377	rc = -EBUSY;
 378	if (fsi->policy_opened)
 379		goto err;
 380
 381	rc = -ENOMEM;
 382	plm = kzalloc(sizeof(*plm), GFP_KERNEL);
 383	if (!plm)
 384		goto err;
 385
 386	rc = security_read_policy(&plm->data, &plm->len);
 387	if (rc)
 388		goto err;
 389
 390	if ((size_t)i_size_read(inode) != plm->len) {
 391		inode_lock(inode);
 392		i_size_write(inode, plm->len);
 393		inode_unlock(inode);
 394	}
 395
 396	fsi->policy_opened = 1;
 397
 398	filp->private_data = plm;
 399
 400	mutex_unlock(&selinux_state.policy_mutex);
 401
 402	return 0;
 403err:
 404	mutex_unlock(&selinux_state.policy_mutex);
 405
 406	if (plm)
 407		vfree(plm->data);
 408	kfree(plm);
 409	return rc;
 410}
 411
 412static int sel_release_policy(struct inode *inode, struct file *filp)
 413{
 414	struct selinux_fs_info *fsi = inode->i_sb->s_fs_info;
 415	struct policy_load_memory *plm = filp->private_data;
 416
 417	BUG_ON(!plm);
 418
 419	fsi->policy_opened = 0;
 420
 421	vfree(plm->data);
 422	kfree(plm);
 423
 424	return 0;
 425}
 426
 427static ssize_t sel_read_policy(struct file *filp, char __user *buf,
 428			       size_t count, loff_t *ppos)
 429{
 430	struct policy_load_memory *plm = filp->private_data;
 431	int ret;
 432
 433	ret = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 434			  SECCLASS_SECURITY, SECURITY__READ_POLICY, NULL);
 435	if (ret)
 436		return ret;
 437
 438	return simple_read_from_buffer(buf, count, ppos, plm->data, plm->len);
 439}
 440
 441static vm_fault_t sel_mmap_policy_fault(struct vm_fault *vmf)
 442{
 443	struct policy_load_memory *plm = vmf->vma->vm_file->private_data;
 444	unsigned long offset;
 445	struct page *page;
 446
 447	if (vmf->flags & (FAULT_FLAG_MKWRITE | FAULT_FLAG_WRITE))
 448		return VM_FAULT_SIGBUS;
 449
 450	offset = vmf->pgoff << PAGE_SHIFT;
 451	if (offset >= roundup(plm->len, PAGE_SIZE))
 452		return VM_FAULT_SIGBUS;
 453
 454	page = vmalloc_to_page(plm->data + offset);
 455	get_page(page);
 456
 457	vmf->page = page;
 458
 459	return 0;
 460}
 461
 462static const struct vm_operations_struct sel_mmap_policy_ops = {
 463	.fault = sel_mmap_policy_fault,
 464	.page_mkwrite = sel_mmap_policy_fault,
 465};
 466
 467static int sel_mmap_policy(struct file *filp, struct vm_area_struct *vma)
 468{
 469	if (vma->vm_flags & VM_SHARED) {
 470		/* do not allow mprotect to make mapping writable */
 471		vm_flags_clear(vma, VM_MAYWRITE);
 472
 473		if (vma->vm_flags & VM_WRITE)
 474			return -EACCES;
 475	}
 476
 477	vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP);
 478	vma->vm_ops = &sel_mmap_policy_ops;
 479
 480	return 0;
 481}
 482
 483static const struct file_operations sel_policy_ops = {
 484	.open		= sel_open_policy,
 485	.read		= sel_read_policy,
 486	.mmap		= sel_mmap_policy,
 487	.release	= sel_release_policy,
 488	.llseek		= generic_file_llseek,
 489};
 490
 491static void sel_remove_old_bool_data(unsigned int bool_num, char **bool_names,
 492				     int *bool_values)
 493{
 494	u32 i;
 495
 496	/* bool_dir cleanup */
 497	for (i = 0; i < bool_num; i++)
 498		kfree(bool_names[i]);
 499	kfree(bool_names);
 500	kfree(bool_values);
 501}
 502
 503static int sel_make_policy_nodes(struct selinux_fs_info *fsi,
 504				struct selinux_policy *newpolicy)
 505{
 506	int ret = 0;
 507	struct dentry *tmp_parent, *tmp_bool_dir, *tmp_class_dir;
 508	struct renamedata rd = {};
 509	unsigned int bool_num = 0;
 510	char **bool_names = NULL;
 511	int *bool_values = NULL;
 512	unsigned long tmp_ino = fsi->last_ino; /* Don't increment last_ino in this function */
 513
 514	tmp_parent = sel_make_swapover_dir(fsi->sb, &tmp_ino);
 515	if (IS_ERR(tmp_parent))
 516		return PTR_ERR(tmp_parent);
 517
 518	tmp_ino = fsi->bool_dir->d_inode->i_ino - 1; /* sel_make_dir will increment and set */
 519	tmp_bool_dir = sel_make_dir(tmp_parent, BOOL_DIR_NAME, &tmp_ino);
 520	if (IS_ERR(tmp_bool_dir)) {
 521		ret = PTR_ERR(tmp_bool_dir);
 522		goto out;
 523	}
 524
 525	tmp_ino = fsi->class_dir->d_inode->i_ino - 1; /* sel_make_dir will increment and set */
 526	tmp_class_dir = sel_make_dir(tmp_parent, CLASS_DIR_NAME, &tmp_ino);
 527	if (IS_ERR(tmp_class_dir)) {
 528		ret = PTR_ERR(tmp_class_dir);
 529		goto out;
 530	}
 531
 532	ret = sel_make_bools(newpolicy, tmp_bool_dir, &bool_num,
 533			     &bool_names, &bool_values);
 534	if (ret)
 535		goto out;
 536
 537	ret = sel_make_classes(newpolicy, tmp_class_dir,
 538			       &fsi->last_class_ino);
 539	if (ret)
 540		goto out;
 541
 542	rd.old_parent = tmp_parent;
 543	rd.new_parent = fsi->sb->s_root;
 544
 545	/* booleans */
 546	ret = start_renaming_two_dentries(&rd, tmp_bool_dir, fsi->bool_dir);
 547	if (ret)
 548		goto out;
 549
 550	d_exchange(tmp_bool_dir, fsi->bool_dir);
 551
 552	swap(fsi->bool_num, bool_num);
 553	swap(fsi->bool_pending_names, bool_names);
 554	swap(fsi->bool_pending_values, bool_values);
 555
 556	fsi->bool_dir = tmp_bool_dir;
 557	end_renaming(&rd);
 558
 559	/* classes */
 560	ret = start_renaming_two_dentries(&rd, tmp_class_dir, fsi->class_dir);
 561	if (ret)
 562		goto out;
 563
 564	d_exchange(tmp_class_dir, fsi->class_dir);
 565	fsi->class_dir = tmp_class_dir;
 566
 567	end_renaming(&rd);
 568
 569out:
 570	sel_remove_old_bool_data(bool_num, bool_names, bool_values);
 571	/* Since the other temporary dirs are children of tmp_parent
 572	 * this will handle all the cleanup in the case of a failure before
 573	 * the swapover
 574	 */
 575	simple_recursive_removal(tmp_parent, NULL);
 576
 577	return ret;
 578}
 579
 580static ssize_t sel_write_load(struct file *file, const char __user *buf,
 581			      size_t count, loff_t *ppos)
 582
 583{
 584	struct selinux_fs_info *fsi;
 585	struct selinux_load_state load_state;
 586	ssize_t length;
 587	void *data = NULL;
 588
 589	/* no partial writes */
 590	if (*ppos)
 591		return -EINVAL;
 592	/* no empty policies */
 593	if (!count)
 594		return -EINVAL;
 595
 596	mutex_lock(&selinux_state.policy_mutex);
 597
 598	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 599			      SECCLASS_SECURITY, SECURITY__LOAD_POLICY, NULL);
 600	if (length)
 601		goto out;
 602
 603	data = vmalloc(count);
 604	if (!data) {
 605		length = -ENOMEM;
 606		goto out;
 607	}
 608	if (copy_from_user(data, buf, count) != 0) {
 609		length = -EFAULT;
 610		goto out;
 611	}
 612
 613	length = security_load_policy(data, count, &load_state);
 614	if (length) {
 615		pr_warn_ratelimited("SELinux: failed to load policy\n");
 616		goto out;
 617	}
 618	fsi = file_inode(file)->i_sb->s_fs_info;
 619	length = sel_make_policy_nodes(fsi, load_state.policy);
 620	if (length) {
 621		pr_warn_ratelimited("SELinux: failed to initialize selinuxfs\n");
 622		selinux_policy_cancel(&load_state);
 623		goto out;
 624	}
 625
 626	selinux_policy_commit(&load_state);
 627	length = count;
 628	audit_log(audit_context(), GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
 629		"auid=%u ses=%u lsm=selinux res=1",
 630		from_kuid(&init_user_ns, audit_get_loginuid(current)),
 631		audit_get_sessionid(current));
 632
 633out:
 634	mutex_unlock(&selinux_state.policy_mutex);
 635	vfree(data);
 636	return length;
 637}
 638
 639static const struct file_operations sel_load_ops = {
 640	.write		= sel_write_load,
 641	.llseek		= generic_file_llseek,
 642};
 643
 644static ssize_t sel_write_context(struct file *file, char *buf, size_t size)
 645{
 646	char *canon = NULL;
 647	u32 sid, len;
 648	ssize_t length;
 649
 650	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 651			      SECCLASS_SECURITY, SECURITY__CHECK_CONTEXT, NULL);
 652	if (length)
 653		goto out;
 654
 655	length = security_context_to_sid(buf, size, &sid, GFP_KERNEL);
 656	if (length)
 657		goto out;
 658
 659	length = security_sid_to_context(sid, &canon, &len);
 660	if (length)
 661		goto out;
 662
 663	length = -ERANGE;
 664	if (len > SIMPLE_TRANSACTION_LIMIT) {
 665		pr_err("SELinux: %s:  context size (%u) exceeds "
 666			"payload max\n", __func__, len);
 667		goto out;
 668	}
 669
 670	memcpy(buf, canon, len);
 671	length = len;
 672out:
 673	kfree(canon);
 674	return length;
 675}
 676
 677static ssize_t sel_read_checkreqprot(struct file *filp, char __user *buf,
 678				     size_t count, loff_t *ppos)
 679{
 680	char tmpbuf[TMPBUFLEN];
 681	ssize_t length;
 682
 683	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
 684			   checkreqprot_get());
 685	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
 686}
 687
 688static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf,
 689				      size_t count, loff_t *ppos)
 690{
 691	char *page;
 692	ssize_t length;
 693	unsigned int new_value;
 694
 695	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 696			      SECCLASS_SECURITY, SECURITY__SETCHECKREQPROT,
 697			      NULL);
 698	if (length)
 699		return length;
 700
 701	if (count >= PAGE_SIZE)
 702		return -ENOMEM;
 703
 704	/* No partial writes. */
 705	if (*ppos != 0)
 706		return -EINVAL;
 707
 708	page = memdup_user_nul(buf, count);
 709	if (IS_ERR(page))
 710		return PTR_ERR(page);
 711
 712	if (sscanf(page, "%u", &new_value) != 1) {
 713		length = -EINVAL;
 714		goto out;
 715	}
 716	length = count;
 717
 718	if (new_value) {
 719		char comm[sizeof(current->comm)];
 720
 721		strscpy(comm, current->comm);
 722		pr_err("SELinux: %s (%d) set checkreqprot to 1. This is no longer supported.\n",
 723		       comm, current->pid);
 724	}
 725
 726	selinux_ima_measure_state();
 727
 728out:
 729	kfree(page);
 730	return length;
 731}
 732static const struct file_operations sel_checkreqprot_ops = {
 733	.read		= sel_read_checkreqprot,
 734	.write		= sel_write_checkreqprot,
 735	.llseek		= generic_file_llseek,
 736};
 737
 738static ssize_t sel_write_validatetrans(struct file *file,
 739					const char __user *buf,
 740					size_t count, loff_t *ppos)
 741{
 742	char *oldcon = NULL, *newcon = NULL, *taskcon = NULL;
 743	char *req = NULL;
 744	u32 osid, nsid, tsid;
 745	u16 tclass;
 746	int rc;
 747
 748	rc = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 749			  SECCLASS_SECURITY, SECURITY__VALIDATE_TRANS, NULL);
 750	if (rc)
 751		goto out;
 752
 753	rc = -ENOMEM;
 754	if (count >= PAGE_SIZE)
 755		goto out;
 756
 757	/* No partial writes. */
 758	rc = -EINVAL;
 759	if (*ppos != 0)
 760		goto out;
 761
 762	req = memdup_user_nul(buf, count);
 763	if (IS_ERR(req)) {
 764		rc = PTR_ERR(req);
 765		req = NULL;
 766		goto out;
 767	}
 768
 769	rc = -ENOMEM;
 770	oldcon = kzalloc(count + 1, GFP_KERNEL);
 771	if (!oldcon)
 772		goto out;
 773
 774	newcon = kzalloc(count + 1, GFP_KERNEL);
 775	if (!newcon)
 776		goto out;
 777
 778	taskcon = kzalloc(count + 1, GFP_KERNEL);
 779	if (!taskcon)
 780		goto out;
 781
 782	rc = -EINVAL;
 783	if (sscanf(req, "%s %s %hu %s", oldcon, newcon, &tclass, taskcon) != 4)
 784		goto out;
 785
 786	rc = security_context_str_to_sid(oldcon, &osid, GFP_KERNEL);
 787	if (rc)
 788		goto out;
 789
 790	rc = security_context_str_to_sid(newcon, &nsid, GFP_KERNEL);
 791	if (rc)
 792		goto out;
 793
 794	rc = security_context_str_to_sid(taskcon, &tsid, GFP_KERNEL);
 795	if (rc)
 796		goto out;
 797
 798	rc = security_validate_transition_user(osid, nsid, tsid, tclass);
 799	if (!rc)
 800		rc = count;
 801out:
 802	kfree(req);
 803	kfree(oldcon);
 804	kfree(newcon);
 805	kfree(taskcon);
 806	return rc;
 807}
 808
 809static const struct file_operations sel_transition_ops = {
 810	.write		= sel_write_validatetrans,
 811	.llseek		= generic_file_llseek,
 812};
 813
 814/*
 815 * Remaining nodes use transaction based IO methods like nfsd/nfsctl.c
 816 */
 817static ssize_t sel_write_access(struct file *file, char *buf, size_t size);
 818static ssize_t sel_write_create(struct file *file, char *buf, size_t size);
 819static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size);
 820static ssize_t sel_write_user(struct file *file, char *buf, size_t size);
 821static ssize_t sel_write_member(struct file *file, char *buf, size_t size);
 822
 823static ssize_t (*const write_op[])(struct file *, char *, size_t) = {
 824	[SEL_ACCESS] = sel_write_access,
 825	[SEL_CREATE] = sel_write_create,
 826	[SEL_RELABEL] = sel_write_relabel,
 827	[SEL_USER] = sel_write_user,
 828	[SEL_MEMBER] = sel_write_member,
 829	[SEL_CONTEXT] = sel_write_context,
 830};
 831
 832static ssize_t selinux_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
 833{
 834	ino_t ino = file_inode(file)->i_ino;
 835	char *data;
 836	ssize_t rv;
 837
 838	if (ino >= ARRAY_SIZE(write_op) || !write_op[ino])
 839		return -EINVAL;
 840
 841	data = simple_transaction_get(file, buf, size);
 842	if (IS_ERR(data))
 843		return PTR_ERR(data);
 844
 845	rv = write_op[ino](file, data, size);
 846	if (rv > 0) {
 847		simple_transaction_set(file, rv);
 848		rv = size;
 849	}
 850	return rv;
 851}
 852
 853static const struct file_operations transaction_ops = {
 854	.write		= selinux_transaction_write,
 855	.read		= simple_transaction_read,
 856	.release	= simple_transaction_release,
 857	.llseek		= generic_file_llseek,
 858};
 859
 860/*
 861 * payload - write methods
 862 * If the method has a response, the response should be put in buf,
 863 * and the length returned.  Otherwise return 0 or and -error.
 864 */
 865
 866static ssize_t sel_write_access(struct file *file, char *buf, size_t size)
 867{
 868	char *scon = NULL, *tcon = NULL;
 869	u32 ssid, tsid;
 870	u16 tclass;
 871	struct av_decision avd;
 872	ssize_t length;
 873
 874	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 875			      SECCLASS_SECURITY, SECURITY__COMPUTE_AV, NULL);
 876	if (length)
 877		goto out;
 878
 879	length = -ENOMEM;
 880	scon = kzalloc(size + 1, GFP_KERNEL);
 881	if (!scon)
 882		goto out;
 883
 884	length = -ENOMEM;
 885	tcon = kzalloc(size + 1, GFP_KERNEL);
 886	if (!tcon)
 887		goto out;
 888
 889	length = -EINVAL;
 890	if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
 891		goto out;
 892
 893	length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
 894	if (length)
 895		goto out;
 896
 897	length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
 898	if (length)
 899		goto out;
 900
 901	security_compute_av_user(ssid, tsid, tclass, &avd);
 902
 903	length = scnprintf(buf, SIMPLE_TRANSACTION_LIMIT,
 904			  "%x %x %x %x %u %x",
 905			  avd.allowed, 0xffffffff,
 906			  avd.auditallow, avd.auditdeny,
 907			  avd.seqno, avd.flags);
 908out:
 909	kfree(tcon);
 910	kfree(scon);
 911	return length;
 912}
 913
 914static ssize_t sel_write_create(struct file *file, char *buf, size_t size)
 915{
 916	char *scon = NULL, *tcon = NULL;
 917	char *namebuf = NULL, *objname = NULL;
 918	u32 ssid, tsid, newsid;
 919	u16 tclass;
 920	ssize_t length;
 921	char *newcon = NULL;
 922	u32 len;
 923	int nargs;
 924
 925	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
 926			      SECCLASS_SECURITY, SECURITY__COMPUTE_CREATE,
 927			      NULL);
 928	if (length)
 929		goto out;
 930
 931	length = -ENOMEM;
 932	scon = kzalloc(size + 1, GFP_KERNEL);
 933	if (!scon)
 934		goto out;
 935
 936	length = -ENOMEM;
 937	tcon = kzalloc(size + 1, GFP_KERNEL);
 938	if (!tcon)
 939		goto out;
 940
 941	length = -ENOMEM;
 942	namebuf = kzalloc(size + 1, GFP_KERNEL);
 943	if (!namebuf)
 944		goto out;
 945
 946	length = -EINVAL;
 947	nargs = sscanf(buf, "%s %s %hu %s", scon, tcon, &tclass, namebuf);
 948	if (nargs < 3 || nargs > 4)
 949		goto out;
 950	if (nargs == 4) {
 951		/*
 952		 * If and when the name of new object to be queried contains
 953		 * either whitespace or multibyte characters, they shall be
 954		 * encoded based on the percentage-encoding rule.
 955		 * If not encoded, the sscanf logic picks up only left-half
 956		 * of the supplied name; split by a whitespace unexpectedly.
 957		 */
 958		char   *r, *w;
 959		int     c1, c2;
 960
 961		r = w = namebuf;
 962		do {
 963			c1 = *r++;
 964			if (c1 == '+')
 965				c1 = ' ';
 966			else if (c1 == '%') {
 967				c1 = hex_to_bin(*r++);
 968				if (c1 < 0)
 969					goto out;
 970				c2 = hex_to_bin(*r++);
 971				if (c2 < 0)
 972					goto out;
 973				c1 = (c1 << 4) | c2;
 974			}
 975			*w++ = c1;
 976		} while (c1 != '\0');
 977
 978		objname = namebuf;
 979	}
 980
 981	length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
 982	if (length)
 983		goto out;
 984
 985	length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
 986	if (length)
 987		goto out;
 988
 989	length = security_transition_sid_user(ssid, tsid, tclass,
 990					      objname, &newsid);
 991	if (length)
 992		goto out;
 993
 994	length = security_sid_to_context(newsid, &newcon, &len);
 995	if (length)
 996		goto out;
 997
 998	length = -ERANGE;
 999	if (len > SIMPLE_TRANSACTION_LIMIT) {
1000		pr_err("SELinux: %s:  context size (%u) exceeds "
1001			"payload max\n", __func__, len);
1002		goto out;
1003	}
1004
1005	memcpy(buf, newcon, len);
1006	length = len;
1007out:
1008	kfree(newcon);
1009	kfree(namebuf);
1010	kfree(tcon);
1011	kfree(scon);
1012	return length;
1013}
1014
1015static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size)
1016{
1017	char *scon = NULL, *tcon = NULL;
1018	u32 ssid, tsid, newsid;
1019	u16 tclass;
1020	ssize_t length;
1021	char *newcon = NULL;
1022	u32 len;
1023
1024	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
1025			      SECCLASS_SECURITY, SECURITY__COMPUTE_RELABEL,
1026			      NULL);
1027	if (length)
1028		goto out;
1029
1030	length = -ENOMEM;
1031	scon = kzalloc(size + 1, GFP_KERNEL);
1032	if (!scon)
1033		goto out;
1034
1035	length = -ENOMEM;
1036	tcon = kzalloc(size + 1, GFP_KERNEL);
1037	if (!tcon)
1038		goto out;
1039
1040	length = -EINVAL;
1041	if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
1042		goto out;
1043
1044	length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
1045	if (length)
1046		goto out;
1047
1048	length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
1049	if (length)
1050		goto out;
1051
1052	length = security_change_sid(ssid, tsid, tclass, &newsid);
1053	if (length)
1054		goto out;
1055
1056	length = security_sid_to_context(newsid, &newcon, &len);
1057	if (length)
1058		goto out;
1059
1060	length = -ERANGE;
1061	if (len > SIMPLE_TRANSACTION_LIMIT)
1062		goto out;
1063
1064	memcpy(buf, newcon, len);
1065	length = len;
1066out:
1067	kfree(newcon);
1068	kfree(tcon);
1069	kfree(scon);
1070	return length;
1071}
1072
1073static ssize_t sel_write_user(struct file *file, char *buf, size_t size)
1074{
1075	char *con = NULL, *user = NULL, *ptr;
1076	u32 sid, *sids = NULL;
1077	ssize_t length;
1078	char *newcon;
1079	int rc;
1080	u32 i, len, nsids;
1081
1082	pr_warn_ratelimited("SELinux: %s (%d) wrote to /sys/fs/selinux/user!"
1083		" This will not be supported in the future; please update your"
1084		" userspace.\n", current->comm, current->pid);
1085	ssleep(5);
1086
1087	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
1088			      SECCLASS_SECURITY, SECURITY__COMPUTE_USER,
1089			      NULL);
1090	if (length)
1091		goto out;
1092
1093	length = -ENOMEM;
1094	con = kzalloc(size + 1, GFP_KERNEL);
1095	if (!con)
1096		goto out;
1097
1098	length = -ENOMEM;
1099	user = kzalloc(size + 1, GFP_KERNEL);
1100	if (!user)
1101		goto out;
1102
1103	length = -EINVAL;
1104	if (sscanf(buf, "%s %s", con, user) != 2)
1105		goto out;
1106
1107	length = security_context_str_to_sid(con, &sid, GFP_KERNEL);
1108	if (length)
1109		goto out;
1110
1111	length = security_get_user_sids(sid, user, &sids, &nsids);
1112	if (length)
1113		goto out;
1114
1115	length = sprintf(buf, "%u", nsids) + 1;
1116	ptr = buf + length;
1117	for (i = 0; i < nsids; i++) {
1118		rc = security_sid_to_context(sids[i], &newcon, &len);
1119		if (rc) {
1120			length = rc;
1121			goto out;
1122		}
1123		if ((length + len) >= SIMPLE_TRANSACTION_LIMIT) {
1124			kfree(newcon);
1125			length = -ERANGE;
1126			goto out;
1127		}
1128		memcpy(ptr, newcon, len);
1129		kfree(newcon);
1130		ptr += len;
1131		length += len;
1132	}
1133out:
1134	kfree(sids);
1135	kfree(user);
1136	kfree(con);
1137	return length;
1138}
1139
1140static ssize_t sel_write_member(struct file *file, char *buf, size_t size)
1141{
1142	char *scon = NULL, *tcon = NULL;
1143	u32 ssid, tsid, newsid;
1144	u16 tclass;
1145	ssize_t length;
1146	char *newcon = NULL;
1147	u32 len;
1148
1149	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
1150			      SECCLASS_SECURITY, SECURITY__COMPUTE_MEMBER,
1151			      NULL);
1152	if (length)
1153		goto out;
1154
1155	length = -ENOMEM;
1156	scon = kzalloc(size + 1, GFP_KERNEL);
1157	if (!scon)
1158		goto out;
1159
1160	length = -ENOMEM;
1161	tcon = kzalloc(size + 1, GFP_KERNEL);
1162	if (!tcon)
1163		goto out;
1164
1165	length = -EINVAL;
1166	if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
1167		goto out;
1168
1169	length = security_context_str_to_sid(scon, &ssid, GFP_KERNEL);
1170	if (length)
1171		goto out;
1172
1173	length = security_context_str_to_sid(tcon, &tsid, GFP_KERNEL);
1174	if (length)
1175		goto out;
1176
1177	length = security_member_sid(ssid, tsid, tclass, &newsid);
1178	if (length)
1179		goto out;
1180
1181	length = security_sid_to_context(newsid, &newcon, &len);
1182	if (length)
1183		goto out;
1184
1185	length = -ERANGE;
1186	if (len > SIMPLE_TRANSACTION_LIMIT) {
1187		pr_err("SELinux: %s:  context size (%u) exceeds "
1188			"payload max\n", __func__, len);
1189		goto out;
1190	}
1191
1192	memcpy(buf, newcon, len);
1193	length = len;
1194out:
1195	kfree(newcon);
1196	kfree(tcon);
1197	kfree(scon);
1198	return length;
1199}
1200
1201static struct inode *sel_make_inode(struct super_block *sb, umode_t mode)
1202{
1203	struct inode *ret = new_inode(sb);
1204
1205	if (ret) {
1206		ret->i_mode = mode;
1207		simple_inode_init_ts(ret);
1208	}
1209	return ret;
1210}
1211
1212static struct dentry *sel_attach(struct dentry *parent, const char *name,
1213				 struct inode *inode)
1214{
1215	struct dentry *dentry = d_alloc_name(parent, name);
1216	if (unlikely(!dentry)) {
1217		iput(inode);
1218		return ERR_PTR(-ENOMEM);
1219	}
1220	d_make_persistent(dentry, inode);
1221	dput(dentry);
1222	return dentry;
1223}
1224
1225static int sel_attach_file(struct dentry *parent, const char *name,
1226			   struct inode *inode)
1227{
1228	struct dentry *dentry = sel_attach(parent, name, inode);
1229	return PTR_ERR_OR_ZERO(dentry);
1230}
1231
1232static ssize_t sel_read_bool(struct file *filep, char __user *buf,
1233			     size_t count, loff_t *ppos)
1234{
1235	struct selinux_fs_info *fsi = file_inode(filep)->i_sb->s_fs_info;
1236	char buffer[4];
1237	ssize_t length;
1238	ssize_t ret;
1239	int cur_enforcing;
1240	unsigned index = file_inode(filep)->i_ino & SEL_INO_MASK;
1241	const char *name = filep->f_path.dentry->d_name.name;
1242
1243	mutex_lock(&selinux_state.policy_mutex);
1244
1245	ret = -EINVAL;
1246	if (index >= fsi->bool_num || strcmp(name,
1247					     fsi->bool_pending_names[index]))
1248		goto out_unlock;
1249
1250	cur_enforcing = security_get_bool_value(index);
1251	if (cur_enforcing < 0) {
1252		ret = cur_enforcing;
1253		goto out_unlock;
1254	}
1255	length = scnprintf(buffer, sizeof(buffer), "%d %d", !!cur_enforcing,
1256			  !!fsi->bool_pending_values[index]);
1257	mutex_unlock(&selinux_state.policy_mutex);
1258	return simple_read_from_buffer(buf, count, ppos, buffer, length);
1259
1260out_unlock:
1261	mutex_unlock(&selinux_state.policy_mutex);
1262	return ret;
1263}
1264
1265static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
1266			      size_t count, loff_t *ppos)
1267{
1268	struct selinux_fs_info *fsi = file_inode(filep)->i_sb->s_fs_info;
1269	char *page = NULL;
1270	ssize_t length;
1271	int new_value;
1272	unsigned index = file_inode(filep)->i_ino & SEL_INO_MASK;
1273	const char *name = filep->f_path.dentry->d_name.name;
1274
1275	if (count >= PAGE_SIZE)
1276		return -ENOMEM;
1277
1278	/* No partial writes. */
1279	if (*ppos != 0)
1280		return -EINVAL;
1281
1282	page = memdup_user_nul(buf, count);
1283	if (IS_ERR(page))
1284		return PTR_ERR(page);
1285
1286	mutex_lock(&selinux_state.policy_mutex);
1287
1288	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
1289			      SECCLASS_SECURITY, SECURITY__SETBOOL,
1290			      NULL);
1291	if (length)
1292		goto out;
1293
1294	length = -EINVAL;
1295	if (index >= fsi->bool_num || strcmp(name,
1296					     fsi->bool_pending_names[index]))
1297		goto out;
1298
1299	length = -EINVAL;
1300	if (sscanf(page, "%d", &new_value) != 1)
1301		goto out;
1302
1303	if (new_value)
1304		new_value = 1;
1305
1306	fsi->bool_pending_values[index] = new_value;
1307	length = count;
1308
1309out:
1310	mutex_unlock(&selinux_state.policy_mutex);
1311	kfree(page);
1312	return length;
1313}
1314
1315static const struct file_operations sel_bool_ops = {
1316	.read		= sel_read_bool,
1317	.write		= sel_write_bool,
1318	.llseek		= generic_file_llseek,
1319};
1320
1321static ssize_t sel_commit_bools_write(struct file *filep,
1322				      const char __user *buf,
1323				      size_t count, loff_t *ppos)
1324{
1325	struct selinux_fs_info *fsi = file_inode(filep)->i_sb->s_fs_info;
1326	char *page = NULL;
1327	ssize_t length;
1328	int new_value;
1329
1330	if (count >= PAGE_SIZE)
1331		return -ENOMEM;
1332
1333	/* No partial writes. */
1334	if (*ppos != 0)
1335		return -EINVAL;
1336
1337	page = memdup_user_nul(buf, count);
1338	if (IS_ERR(page))
1339		return PTR_ERR(page);
1340
1341	mutex_lock(&selinux_state.policy_mutex);
1342
1343	length = avc_has_perm(current_sid(), SECINITSID_SECURITY,
1344			      SECCLASS_SECURITY, SECURITY__SETBOOL,
1345			      NULL);
1346	if (length)
1347		goto out;
1348
1349	length = -EINVAL;
1350	if (sscanf(page, "%d", &new_value) != 1)
1351		goto out;
1352
1353	length = 0;
1354	if (new_value && fsi->bool_pending_values)
1355		length = security_set_bools(fsi->bool_num,
1356					    fsi->bool_pending_values);
1357
1358	if (!length)
1359		length = count;
1360
1361out:
1362	mutex_unlock(&selinux_state.policy_mutex);
1363	kfree(page);
1364	return length;
1365}
1366
1367static const struct file_operations sel_commit_bools_ops = {
1368	.write		= sel_commit_bools_write,
1369	.llseek		= generic_file_llseek,
1370};
1371
1372static int sel_make_bools(struct selinux_policy *newpolicy, struct dentry *bool_dir,
1373			  unsigned int *bool_num, char ***bool_pending_names,
1374			  int **bool_pending_values)
1375{
1376	int ret;
1377	char **names, *page;
1378	u32 i, num;
1379
1380	page = (char *)get_zeroed_page(GFP_KERNEL);
1381	if (!page)
1382		return -ENOMEM;
1383
1384	ret = security_get_bools(newpolicy, &num, &names, bool_pending_values);
1385	if (ret)
1386		goto out;
1387
1388	*bool_num = num;
1389	*bool_pending_names = names;
1390
1391	for (i = 0; !ret && i < num; i++) {
1392		struct inode *inode;
1393		struct inode_security_struct *isec;
1394		ssize_t len;
1395		u32 sid;
1396
1397		len = snprintf(page, PAGE_SIZE, "/%s/%s", BOOL_DIR_NAME, names[i]);
1398		if (len >= PAGE_SIZE) {
1399			ret = -ENAMETOOLONG;
1400			break;
1401		}
1402
1403		inode = sel_make_inode(bool_dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR);
1404		if (!inode) {
1405			ret = -ENOMEM;
1406			break;
1407		}
1408
1409		isec = selinux_inode(inode);
1410		ret = selinux_policy_genfs_sid(newpolicy, "selinuxfs", page,
1411					 SECCLASS_FILE, &sid);
1412		if (ret) {
1413			pr_warn_ratelimited("SELinux: no sid found, defaulting to security isid for %s\n",
1414					   page);
1415			sid = SECINITSID_SECURITY;
1416		}
1417
1418		isec->sid = sid;
1419		isec->initialized = LABEL_INITIALIZED;
1420		inode->i_fop = &sel_bool_ops;
1421		inode->i_ino = i|SEL_BOOL_INO_OFFSET;
1422
1423		ret = sel_attach_file(bool_dir, names[i], inode);
1424	}
1425out:
1426	free_page((unsigned long)page);
1427	return ret;
1428}
1429
1430static ssize_t sel_read_avc_cache_threshold(struct file *filp, char __user *buf,
1431					    size_t count, loff_t *ppos)
1432{
1433	char tmpbuf[TMPBUFLEN];
1434	ssize_t length;
1435
1436	length = scnprintf(tmpbuf, TMPBUFLEN, "%u",
1437			   avc_get_cache_threshold());
1438	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1439}
1440
1441static ssize_t sel_write_avc_cache_threshold(struct file *file,
1442					     const char __user *buf,
1443					     size_t count, loff_t *ppos)
1444
1445{
1446	char *page;
1447	ssize_t ret;
1448	unsigned int new_value;
1449
1450	ret = avc_has_perm(current_sid(), SECINITSID_SECURITY,
1451			   SECCLASS_SECURITY, SECURITY__SETSECPARAM,
1452			   NULL);
1453	if (ret)
1454		return ret;
1455
1456	if (count >= PAGE_SIZE)
1457		return -ENOMEM;
1458
1459	/* No partial writes. */
1460	if (*ppos != 0)
1461		return -EINVAL;
1462
1463	page = memdup_user_nul(buf, count);
1464	if (IS_ERR(page))
1465		return PTR_ERR(page);
1466
1467	ret = -EINVAL;
1468	if (sscanf(page, "%u", &new_value) != 1)
1469		goto out;
1470
1471	avc_set_cache_threshold(new_value);
1472
1473	ret = count;
1474out:
1475	kfree(page);
1476	return ret;
1477}
1478
1479static ssize_t sel_read_avc_hash_stats(struct file *filp, char __user *buf,
1480				       size_t count, loff_t *ppos)
1481{
1482	char *page;
1483	ssize_t length;
1484
1485	page = (char *)__get_free_page(GFP_KERNEL);
1486	if (!page)
1487		return -ENOMEM;
1488
1489	length = avc_get_hash_stats(page);
1490	if (length >= 0)
1491		length = simple_read_from_buffer(buf, count, ppos, page, length);
1492	free_page((unsigned long)page);
1493
1494	return length;
1495}
1496
1497static ssize_t sel_read_sidtab_hash_stats(struct file *filp, char __user *buf,
1498					size_t count, loff_t *ppos)
1499{
1500	char *page;
1501	ssize_t length;
1502
1503	page = (char *)__get_free_page(GFP_KERNEL);
1504	if (!page)
1505		return -ENOMEM;
1506
1507	length = security_sidtab_hash_stats(page);
1508	if (length >= 0)
1509		length = simple_read_from_buffer(buf, count, ppos, page,
1510						length);
1511	free_page((unsigned long)page);
1512
1513	return length;
1514}
1515
1516static const struct file_operations sel_sidtab_hash_stats_ops = {
1517	.read		= sel_read_sidtab_hash_stats,
1518	.llseek		= generic_file_llseek,
1519};
1520
1521static const struct file_operations sel_avc_cache_threshold_ops = {
1522	.read		= sel_read_avc_cache_threshold,
1523	.write		= sel_write_avc_cache_threshold,
1524	.llseek		= generic_file_llseek,
1525};
1526
1527static const struct file_operations sel_avc_hash_stats_ops = {
1528	.read		= sel_read_avc_hash_stats,
1529	.llseek		= generic_file_llseek,
1530};
1531
1532#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
1533static struct avc_cache_stats *sel_avc_get_stat_idx(loff_t *idx)
1534{
1535	loff_t cpu;
1536
1537	for (cpu = *idx; cpu < nr_cpu_ids; ++cpu) {
1538		if (!cpu_possible(cpu))
1539			continue;
1540		*idx = cpu + 1;
1541		return &per_cpu(avc_cache_stats, cpu);
1542	}
1543	(*idx)++;
1544	return NULL;
1545}
1546
1547static void *sel_avc_stats_seq_start(struct seq_file *seq, loff_t *pos)
1548{
1549	loff_t n = *pos - 1;
1550
1551	if (*pos == 0)
1552		return SEQ_START_TOKEN;
1553
1554	return sel_avc_get_stat_idx(&n);
1555}
1556
1557static void *sel_avc_stats_seq_next(struct seq_file *seq, void *v, loff_t *pos)
1558{
1559	return sel_avc_get_stat_idx(pos);
1560}
1561
1562static int sel_avc_stats_seq_show(struct seq_file *seq, void *v)
1563{
1564	struct avc_cache_stats *st = v;
1565
1566	if (v == SEQ_START_TOKEN) {
1567		seq_puts(seq,
1568			 "lookups hits misses allocations reclaims frees\n");
1569	} else {
1570		unsigned int lookups = st->lookups;
1571		unsigned int misses = st->misses;
1572		unsigned int hits = lookups - misses;
1573		seq_printf(seq, "%u %u %u %u %u %u\n", lookups,
1574			   hits, misses, st->allocations,
1575			   st->reclaims, st->frees);
1576	}
1577	return 0;
1578}
1579
1580static void sel_avc_stats_seq_stop(struct seq_file *seq, void *v)
1581{ }
1582
1583static const struct seq_operations sel_avc_cache_stats_seq_ops = {
1584	.start		= sel_avc_stats_seq_start,
1585	.next		= sel_avc_stats_seq_next,
1586	.show		= sel_avc_stats_seq_show,
1587	.stop		= sel_avc_stats_seq_stop,
1588};
1589
1590static int sel_open_avc_cache_stats(struct inode *inode, struct file *file)
1591{
1592	return seq_open(file, &sel_avc_cache_stats_seq_ops);
1593}
1594
1595static const struct file_operations sel_avc_cache_stats_ops = {
1596	.open		= sel_open_avc_cache_stats,
1597	.read		= seq_read,
1598	.llseek		= seq_lseek,
1599	.release	= seq_release,
1600};
1601#endif
1602
1603static int sel_make_avc_files(struct dentry *dir)
1604{
1605	struct super_block *sb = dir->d_sb;
1606	struct selinux_fs_info *fsi = sb->s_fs_info;
1607	unsigned int i;
1608	int err = 0;
1609	static const struct tree_descr files[] = {
1610		{ "cache_threshold",
1611		  &sel_avc_cache_threshold_ops, S_IRUGO|S_IWUSR },
1612		{ "hash_stats", &sel_avc_hash_stats_ops, S_IRUGO },
1613#ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
1614		{ "cache_stats", &sel_avc_cache_stats_ops, S_IRUGO },
1615#endif
1616	};
1617
1618	for (i = 0; !err && i < ARRAY_SIZE(files); i++) {
1619		struct inode *inode;
1620
1621		inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
1622		if (!inode)
1623			return -ENOMEM;
1624
1625		inode->i_fop = files[i].ops;
1626		inode->i_ino = ++fsi->last_ino;
1627
1628		err = sel_attach_file(dir, files[i].name, inode);
1629	}
1630
1631	return err;
1632}
1633
1634static int sel_make_ss_files(struct dentry *dir)
1635{
1636	struct super_block *sb = dir->d_sb;
1637	struct selinux_fs_info *fsi = sb->s_fs_info;
1638	unsigned int i;
1639	int err = 0;
1640	static const struct tree_descr files[] = {
1641		{ "sidtab_hash_stats", &sel_sidtab_hash_stats_ops, S_IRUGO },
1642	};
1643
1644	for (i = 0; !err && i < ARRAY_SIZE(files); i++) {
1645		struct inode *inode;
1646
1647		inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
1648		if (!inode)
1649			return -ENOMEM;
1650
1651		inode->i_fop = files[i].ops;
1652		inode->i_ino = ++fsi->last_ino;
1653
1654		err = sel_attach_file(dir, files[i].name, inode);
1655	}
1656
1657	return err;
1658}
1659
1660static ssize_t sel_read_initcon(struct file *file, char __user *buf,
1661				size_t count, loff_t *ppos)
1662{
1663	char *con;
1664	u32 sid, len;
1665	ssize_t ret;
1666
1667	sid = file_inode(file)->i_ino&SEL_INO_MASK;
1668	ret = security_sid_to_context(sid, &con, &len);
1669	if (ret)
1670		return ret;
1671
1672	ret = simple_read_from_buffer(buf, count, ppos, con, len);
1673	kfree(con);
1674	return ret;
1675}
1676
1677static const struct file_operations sel_initcon_ops = {
1678	.read		= sel_read_initcon,
1679	.llseek		= generic_file_llseek,
1680};
1681
1682static int sel_make_initcon_files(struct dentry *dir)
1683{
1684	unsigned int i;
1685	int err = 0;
1686
1687	for (i = 1; !err && i <= SECINITSID_NUM; i++) {
1688		const char *s = security_get_initial_sid_context(i);
1689		struct inode *inode;
1690
1691		if (!s)
1692			continue;
1693
1694		inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
1695		if (!inode)
1696			return -ENOMEM;
1697
1698		inode->i_fop = &sel_initcon_ops;
1699		inode->i_ino = i|SEL_INITCON_INO_OFFSET;
1700		err = sel_attach_file(dir, s, inode);
1701	}
1702
1703	return err;
1704}
1705
1706static inline unsigned long sel_class_to_ino(u16 class)
1707{
1708	return (class * (SEL_VEC_MAX + 1)) | SEL_CLASS_INO_OFFSET;
1709}
1710
1711static inline u16 sel_ino_to_class(unsigned long ino)
1712{
1713	return (ino & SEL_INO_MASK) / (SEL_VEC_MAX + 1);
1714}
1715
1716static inline unsigned long sel_perm_to_ino(u16 class, u32 perm)
1717{
1718	return (class * (SEL_VEC_MAX + 1) + perm) | SEL_CLASS_INO_OFFSET;
1719}
1720
1721static inline u32 sel_ino_to_perm(unsigned long ino)
1722{
1723	return (ino & SEL_INO_MASK) % (SEL_VEC_MAX + 1);
1724}
1725
1726static ssize_t sel_read_class(struct file *file, char __user *buf,
1727				size_t count, loff_t *ppos)
1728{
1729	unsigned long ino = file_inode(file)->i_ino;
1730	char res[TMPBUFLEN];
1731	ssize_t len = scnprintf(res, sizeof(res), "%d", sel_ino_to_class(ino));
1732	return simple_read_from_buffer(buf, count, ppos, res, len);
1733}
1734
1735static const struct file_operations sel_class_ops = {
1736	.read		= sel_read_class,
1737	.llseek		= generic_file_llseek,
1738};
1739
1740static ssize_t sel_read_perm(struct file *file, char __user *buf,
1741				size_t count, loff_t *ppos)
1742{
1743	unsigned long ino = file_inode(file)->i_ino;
1744	char res[TMPBUFLEN];
1745	ssize_t len = scnprintf(res, sizeof(res), "%d", sel_ino_to_perm(ino));
1746	return simple_read_from_buffer(buf, count, ppos, res, len);
1747}
1748
1749static const struct file_operations sel_perm_ops = {
1750	.read		= sel_read_perm,
1751	.llseek		= generic_file_llseek,
1752};
1753
1754static ssize_t sel_read_policycap(struct file *file, char __user *buf,
1755				  size_t count, loff_t *ppos)
1756{
1757	int value;
1758	char tmpbuf[TMPBUFLEN];
1759	ssize_t length;
1760	unsigned long i_ino = file_inode(file)->i_ino;
1761
1762	value = security_policycap_supported(i_ino & SEL_INO_MASK);
1763	length = scnprintf(tmpbuf, TMPBUFLEN, "%d", value);
1764
1765	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
1766}
1767
1768static const struct file_operations sel_policycap_ops = {
1769	.read		= sel_read_policycap,
1770	.llseek		= generic_file_llseek,
1771};
1772
1773static int sel_make_perm_files(struct selinux_policy *newpolicy,
1774			char *objclass, int classvalue,
1775			struct dentry *dir)
1776{
1777	u32 i, nperms;
1778	int rc;
1779	char **perms;
1780
1781	rc = security_get_permissions(newpolicy, objclass, &perms, &nperms);
1782	if (rc)
1783		return rc;
1784
1785	for (i = 0; !rc && i < nperms; i++) {
1786		struct inode *inode;
1787
1788		inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
1789		if (!inode) {
1790			rc = -ENOMEM;
1791			break;
1792		}
1793
1794		inode->i_fop = &sel_perm_ops;
1795		/* i+1 since perm values are 1-indexed */
1796		inode->i_ino = sel_perm_to_ino(classvalue, i + 1);
1797
1798		rc = sel_attach_file(dir, perms[i], inode);
1799	}
1800	for (i = 0; i < nperms; i++)
1801		kfree(perms[i]);
1802	kfree(perms);
1803	return rc;
1804}
1805
1806static int sel_make_class_dir_entries(struct selinux_policy *newpolicy,
1807				char *classname, int index,
1808				struct dentry *dir)
1809{
1810	struct super_block *sb = dir->d_sb;
1811	struct selinux_fs_info *fsi = sb->s_fs_info;
1812	struct dentry *dentry = NULL;
1813	struct inode *inode = NULL;
1814	int err;
1815
1816	inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
1817	if (!inode)
1818		return -ENOMEM;
1819
1820	inode->i_fop = &sel_class_ops;
1821	inode->i_ino = sel_class_to_ino(index);
1822
1823	err = sel_attach_file(dir, "index", inode);
1824	if (err)
1825		return err;
1826
1827	dentry = sel_make_dir(dir, "perms", &fsi->last_class_ino);
1828	if (IS_ERR(dentry))
1829		return PTR_ERR(dentry);
1830
1831	return sel_make_perm_files(newpolicy, classname, index, dentry);
1832}
1833
1834static int sel_make_classes(struct selinux_policy *newpolicy,
1835			    struct dentry *class_dir,
1836			    unsigned long *last_class_ino)
1837{
1838	u32 i, nclasses;
1839	int rc;
1840	char **classes;
1841
1842	rc = security_get_classes(newpolicy, &classes, &nclasses);
1843	if (rc)
1844		return rc;
1845
1846	/* +2 since classes are 1-indexed */
1847	*last_class_ino = sel_class_to_ino(nclasses + 2);
1848
1849	for (i = 0; i < nclasses; i++) {
1850		struct dentry *class_name_dir;
1851
1852		class_name_dir = sel_make_dir(class_dir, classes[i],
1853					      last_class_ino);
1854		if (IS_ERR(class_name_dir)) {
1855			rc = PTR_ERR(class_name_dir);
1856			goto out;
1857		}
1858
1859		/* i+1 since class values are 1-indexed */
1860		rc = sel_make_class_dir_entries(newpolicy, classes[i], i + 1,
1861				class_name_dir);
1862		if (rc)
1863			goto out;
1864	}
1865	rc = 0;
1866out:
1867	for (i = 0; i < nclasses; i++)
1868		kfree(classes[i]);
1869	kfree(classes);
1870	return rc;
1871}
1872
1873static int sel_make_policycap(struct dentry *dir)
1874{
1875	struct super_block *sb = dir->d_sb;
1876	unsigned int iter;
1877	struct inode *inode = NULL;
1878	int err = 0;
1879
1880	for (iter = 0; !err && iter <= POLICYDB_CAP_MAX; iter++) {
1881		const char *name;
1882
1883		if (iter < ARRAY_SIZE(selinux_policycap_names))
1884			name = selinux_policycap_names[iter];
1885		else
1886			name = "unknown";
1887
1888		inode = sel_make_inode(sb, S_IFREG | 0444);
1889		if (!inode)
1890			return -ENOMEM;
1891
1892		inode->i_fop = &sel_policycap_ops;
1893		inode->i_ino = iter | SEL_POLICYCAP_INO_OFFSET;
1894		err = sel_attach_file(dir, name, inode);
1895	}
1896
1897	return err;
1898}
1899
1900static struct dentry *sel_make_dir(struct dentry *dir, const char *name,
1901			unsigned long *ino)
1902{
1903	struct inode *inode;
1904
1905	inode = sel_make_inode(dir->d_sb, S_IFDIR | S_IRUGO | S_IXUGO);
1906	if (!inode)
1907		return ERR_PTR(-ENOMEM);
1908
1909	inode->i_op = &simple_dir_inode_operations;
1910	inode->i_fop = &simple_dir_operations;
1911	inode->i_ino = ++(*ino);
1912	/* directory inodes start off with i_nlink == 2 (for "." entry) */
1913	inc_nlink(inode);
1914	/* bump link count on parent directory, too */
1915	inc_nlink(d_inode(dir));
1916
1917	return sel_attach(dir, name, inode);
1918}
1919
1920static int reject_all(struct mnt_idmap *idmap, struct inode *inode, int mask)
1921{
1922	return -EPERM;	// no access for anyone, root or no root.
1923}
1924
1925static const struct inode_operations swapover_dir_inode_operations = {
1926	.lookup		= simple_lookup,
1927	.permission	= reject_all,
1928};
1929
1930static struct dentry *sel_make_swapover_dir(struct super_block *sb,
1931						unsigned long *ino)
1932{
1933	struct dentry *dentry = d_alloc_name(sb->s_root, ".swapover");
1934	struct inode *inode;
1935
1936	if (!dentry)
1937		return ERR_PTR(-ENOMEM);
1938
1939	inode = sel_make_inode(sb, S_IFDIR);
1940	if (!inode) {
1941		dput(dentry);
1942		return ERR_PTR(-ENOMEM);
1943	}
1944
1945	inode->i_op = &swapover_dir_inode_operations;
1946	inode->i_ino = ++(*ino);
1947	/* directory inodes start off with i_nlink == 2 (for "." entry) */
1948	inc_nlink(inode);
1949	inode_lock(sb->s_root->d_inode);
1950	d_make_persistent(dentry, inode);
1951	inc_nlink(sb->s_root->d_inode);
1952	inode_unlock(sb->s_root->d_inode);
1953	dput(dentry);
1954	return dentry;	// borrowed
1955}
1956
1957#define NULL_FILE_NAME "null"
1958
1959static int sel_fill_super(struct super_block *sb, struct fs_context *fc)
1960{
1961	struct selinux_fs_info *fsi;
1962	int ret;
1963	struct dentry *dentry;
1964	struct inode *inode;
1965	struct inode_security_struct *isec;
1966
1967	static const struct tree_descr selinux_files[] = {
1968		[SEL_LOAD] = {"load", &sel_load_ops, S_IRUSR|S_IWUSR},
1969		[SEL_ENFORCE] = {"enforce", &sel_enforce_ops, S_IRUGO|S_IWUSR},
1970		[SEL_CONTEXT] = {"context", &transaction_ops, S_IRUGO|S_IWUGO},
1971		[SEL_ACCESS] = {"access", &transaction_ops, S_IRUGO|S_IWUGO},
1972		[SEL_CREATE] = {"create", &transaction_ops, S_IRUGO|S_IWUGO},
1973		[SEL_RELABEL] = {"relabel", &transaction_ops, S_IRUGO|S_IWUGO},
1974		[SEL_USER] = {"user", &transaction_ops, S_IRUGO|S_IWUGO},
1975		[SEL_POLICYVERS] = {"policyvers", &sel_policyvers_ops, S_IRUGO},
1976		[SEL_COMMIT_BOOLS] = {"commit_pending_bools", &sel_commit_bools_ops, S_IWUSR},
1977		[SEL_MLS] = {"mls", &sel_mls_ops, S_IRUGO},
1978		[SEL_DISABLE] = {"disable", &sel_disable_ops, S_IWUSR},
1979		[SEL_MEMBER] = {"member", &transaction_ops, S_IRUGO|S_IWUGO},
1980		[SEL_CHECKREQPROT] = {"checkreqprot", &sel_checkreqprot_ops, S_IRUGO|S_IWUSR},
1981		[SEL_REJECT_UNKNOWN] = {"reject_unknown", &sel_handle_unknown_ops, S_IRUGO},
1982		[SEL_DENY_UNKNOWN] = {"deny_unknown", &sel_handle_unknown_ops, S_IRUGO},
1983		[SEL_STATUS] = {"status", &sel_handle_status_ops, S_IRUGO},
1984		[SEL_POLICY] = {"policy", &sel_policy_ops, S_IRUGO},
1985		[SEL_VALIDATE_TRANS] = {"validatetrans", &sel_transition_ops,
1986					S_IWUGO},
1987		/* last one */ {"", NULL, 0}
1988	};
1989
1990	ret = selinux_fs_info_create(sb);
1991	if (ret)
1992		goto err;
1993
1994	ret = simple_fill_super(sb, SELINUX_MAGIC, selinux_files);
1995	if (ret)
1996		goto err;
1997
1998	fsi = sb->s_fs_info;
1999	fsi->bool_dir = sel_make_dir(sb->s_root, BOOL_DIR_NAME, &fsi->last_ino);
2000	if (IS_ERR(fsi->bool_dir)) {
2001		ret = PTR_ERR(fsi->bool_dir);
2002		fsi->bool_dir = NULL;
2003		goto err;
2004	}
2005
2006	ret = -ENOMEM;
2007	inode = sel_make_inode(sb, S_IFCHR | S_IRUGO | S_IWUGO);
2008	if (!inode)
2009		goto err;
2010
2011	inode->i_ino = ++fsi->last_ino;
2012	isec = selinux_inode(inode);
2013	isec->sid = SECINITSID_DEVNULL;
2014	isec->sclass = SECCLASS_CHR_FILE;
2015	isec->initialized = LABEL_INITIALIZED;
2016
2017	init_special_inode(inode, S_IFCHR | S_IRUGO | S_IWUGO, MKDEV(MEM_MAJOR, 3));
2018	ret = sel_attach_file(sb->s_root, NULL_FILE_NAME, inode);
2019	if (ret)
2020		goto err;
2021
2022	dentry = sel_make_dir(sb->s_root, "avc", &fsi->last_ino);
2023	if (IS_ERR(dentry)) {
2024		ret = PTR_ERR(dentry);
2025		goto err;
2026	}
2027
2028	ret = sel_make_avc_files(dentry);
2029	if (ret)
2030		goto err;
2031
2032	dentry = sel_make_dir(sb->s_root, "ss", &fsi->last_ino);
2033	if (IS_ERR(dentry)) {
2034		ret = PTR_ERR(dentry);
2035		goto err;
2036	}
2037
2038	ret = sel_make_ss_files(dentry);
2039	if (ret)
2040		goto err;
2041
2042	dentry = sel_make_dir(sb->s_root, "initial_contexts", &fsi->last_ino);
2043	if (IS_ERR(dentry)) {
2044		ret = PTR_ERR(dentry);
2045		goto err;
2046	}
2047
2048	ret = sel_make_initcon_files(dentry);
2049	if (ret)
2050		goto err;
2051
2052	fsi->class_dir = sel_make_dir(sb->s_root, CLASS_DIR_NAME, &fsi->last_ino);
2053	if (IS_ERR(fsi->class_dir)) {
2054		ret = PTR_ERR(fsi->class_dir);
2055		fsi->class_dir = NULL;
2056		goto err;
2057	}
2058
2059	dentry = sel_make_dir(sb->s_root, "policy_capabilities", &fsi->last_ino);
2060	if (IS_ERR(dentry)) {
2061		ret = PTR_ERR(dentry);
2062		goto err;
2063	}
2064
2065	ret = sel_make_policycap(dentry);
2066	if (ret) {
2067		pr_err("SELinux: failed to load policy capabilities\n");
2068		goto err;
2069	}
2070
2071	return 0;
2072err:
2073	pr_err("SELinux: %s:  failed while creating inodes\n",
2074		__func__);
2075
2076	return ret;
2077}
2078
2079static int sel_get_tree(struct fs_context *fc)
2080{
2081	return get_tree_single(fc, sel_fill_super);
2082}
2083
2084static const struct fs_context_operations sel_context_ops = {
2085	.get_tree	= sel_get_tree,
2086};
2087
2088static int sel_init_fs_context(struct fs_context *fc)
2089{
2090	fc->ops = &sel_context_ops;
2091	return 0;
2092}
2093
2094static void sel_kill_sb(struct super_block *sb)
2095{
2096	selinux_fs_info_free(sb);
2097	kill_anon_super(sb);
2098}
2099
2100static struct file_system_type sel_fs_type = {
2101	.name		= "selinuxfs",
2102	.init_fs_context = sel_init_fs_context,
2103	.kill_sb	= sel_kill_sb,
2104};
2105
2106struct path selinux_null __ro_after_init;
2107
2108int __init init_sel_fs(void)
2109{
2110	struct qstr null_name = QSTR_INIT(NULL_FILE_NAME,
2111					  sizeof(NULL_FILE_NAME)-1);
2112	int err;
2113
2114	if (!selinux_enabled_boot)
2115		return 0;
2116
2117	err = sysfs_create_mount_point(fs_kobj, "selinux");
2118	if (err)
2119		return err;
2120
2121	err = register_filesystem(&sel_fs_type);
2122	if (err) {
2123		sysfs_remove_mount_point(fs_kobj, "selinux");
2124		return err;
2125	}
2126
2127	selinux_null.mnt = kern_mount(&sel_fs_type);
2128	if (IS_ERR(selinux_null.mnt)) {
2129		pr_err("selinuxfs:  could not mount!\n");
2130		err = PTR_ERR(selinux_null.mnt);
2131		selinux_null.mnt = NULL;
2132		return err;
2133	}
2134
2135	selinux_null.dentry = try_lookup_noperm(&null_name,
2136						  selinux_null.mnt->mnt_root);
2137	if (IS_ERR(selinux_null.dentry)) {
2138		pr_err("selinuxfs:  could not lookup null!\n");
2139		err = PTR_ERR(selinux_null.dentry);
2140		selinux_null.dentry = NULL;
2141		return err;
2142	}
2143
2144	/*
2145	 * Try to pre-allocate the status page, so the sequence number of the
2146	 * initial policy load can be stored.
2147	 */
2148	(void) selinux_kernel_status_page();
2149
2150	return err;
2151}