text: /* Updated: Karl MacMillan <kmacmillan@tresys.com>
   *
   *	Added conditional policy language extensions
   *
   *  Updated: Hewlett-Packard <paul.moore@hp.com>
   *
   *	Added support for the policy capability bitmap
   *
   * Copyright (C) 2007 Hewlett-Packard Development Company, L.P.
   * Copyright (C) 2003 - 2004 Tresys Technology, LLC
   * Copyright (C) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
   *	This program is free software; you can redistribute it and/or modify
   *	it under the terms of the GNU General Public License as published by
   *	the Free Software Foundation, version 2.
   */
  
  #include <linux/kernel.h>
  #include <linux/pagemap.h>
  #include <linux/slab.h>
  #include <linux/vmalloc.h>
  #include <linux/fs.h>
  #include <linux/mutex.h>
  #include <linux/init.h>
  #include <linux/string.h>
  #include <linux/security.h>
  #include <linux/major.h>
  #include <linux/seq_file.h>
  #include <linux/percpu.h>
  #include <linux/audit.h>
  #include <linux/uaccess.h>
  #include <linux/kobject.h>
  #include <linux/ctype.h>
  
  /* selinuxfs pseudo filesystem for exporting the security policy API.
     Based on the proc code and the fs/nfsd/nfsctl.c code. */
  
  #include "flask.h"
  #include "avc.h"
  #include "avc_ss.h"
  #include "security.h"
  #include "objsec.h"
  #include "conditional.h"
  
  /* Policy capability filenames */
  static char *policycap_names[] = {
  	"network_peer_controls",
  	"open_perms"
  };
  
  unsigned int selinux_checkreqprot = CONFIG_SECURITY_SELINUX_CHECKREQPROT_VALUE;
  
  static int __init checkreqprot_setup(char *str)
  {
  	unsigned long checkreqprot;
  	if (!strict_strtoul(str, 0, &checkreqprot))
  		selinux_checkreqprot = checkreqprot ? 1 : 0;
  	return 1;
  }
  __setup("checkreqprot=", checkreqprot_setup);
  
  static DEFINE_MUTEX(sel_mutex);
  
  /* global data for booleans */
  static struct dentry *bool_dir;
  static int bool_num;
  static char **bool_pending_names;
  static int *bool_pending_values;
  
  /* global data for classes */
  static struct dentry *class_dir;
  static unsigned long last_class_ino;
  
  static char policy_opened;
  
  /* global data for policy capabilities */
  static struct dentry *policycap_dir;
  
  extern void selnl_notify_setenforce(int val);
  
  /* Check whether a task is allowed to use a security operation. */
  static int task_has_security(struct task_struct *tsk,
  			     u32 perms)
  {
  	const struct task_security_struct *tsec;
  	u32 sid = 0;
  
  	rcu_read_lock();
  	tsec = __task_cred(tsk)->security;
  	if (tsec)
  		sid = tsec->sid;
  	rcu_read_unlock();
  	if (!tsec)
  		return -EACCES;
  
  	return avc_has_perm(sid, SECINITSID_SECURITY,
  			    SECCLASS_SECURITY, perms, NULL);
  }
  
  enum sel_inos {
  	SEL_ROOT_INO = 2,
  	SEL_LOAD,	/* load policy */
  	SEL_ENFORCE,	/* get or set enforcing status */
  	SEL_CONTEXT,	/* validate context */
  	SEL_ACCESS,	/* compute access decision */
  	SEL_CREATE,	/* compute create labeling decision */
  	SEL_RELABEL,	/* compute relabeling decision */
  	SEL_USER,	/* compute reachable user contexts */
  	SEL_POLICYVERS,	/* return policy version for this kernel */
  	SEL_COMMIT_BOOLS, /* commit new boolean values */
  	SEL_MLS,	/* return if MLS policy is enabled */
  	SEL_DISABLE,	/* disable SELinux until next reboot */
  	SEL_MEMBER,	/* compute polyinstantiation membership decision */
  	SEL_CHECKREQPROT, /* check requested protection, not kernel-applied one */
  	SEL_COMPAT_NET,	/* whether to use old compat network packet controls */
  	SEL_REJECT_UNKNOWN, /* export unknown reject handling to userspace */
  	SEL_DENY_UNKNOWN, /* export unknown deny handling to userspace */
  	SEL_STATUS,	/* export current status using mmap() */
  	SEL_POLICY,	/* allow userspace to read the in kernel policy */
  	SEL_INO_NEXT,	/* The next inode number to use */
  };
  
  static unsigned long sel_last_ino = SEL_INO_NEXT - 1;
  
  #define SEL_INITCON_INO_OFFSET		0x01000000
  #define SEL_BOOL_INO_OFFSET		0x02000000
  #define SEL_CLASS_INO_OFFSET		0x04000000
  #define SEL_POLICYCAP_INO_OFFSET	0x08000000
  #define SEL_INO_MASK			0x00ffffff
  
  #define TMPBUFLEN	12
  static ssize_t sel_read_enforce(struct file *filp, char __user *buf,
  				size_t count, loff_t *ppos)
  {
  	char tmpbuf[TMPBUFLEN];
  	ssize_t length;
  
  	length = scnprintf(tmpbuf, TMPBUFLEN, "%d", selinux_enforcing);
  	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
  }
  
  #ifdef CONFIG_SECURITY_SELINUX_DEVELOP
  static ssize_t sel_write_enforce(struct file *file, const char __user *buf,
  				 size_t count, loff_t *ppos)
  
  {
  	char *page = NULL;
  	ssize_t length;
  	int new_value;
  
  	length = -ENOMEM;
  	if (count >= PAGE_SIZE)
  		goto out;
  
  	/* No partial writes. */
  	length = EINVAL;
  	if (*ppos != 0)
  		goto out;
  
  	length = -ENOMEM;
  	page = (char *)get_zeroed_page(GFP_KERNEL);
  	if (!page)
  		goto out;
  
  	length = -EFAULT;
  	if (copy_from_user(page, buf, count))
  		goto out;
  
  	length = -EINVAL;
  	if (sscanf(page, "%d", &new_value) != 1)
  		goto out;
  
  	if (new_value != selinux_enforcing) {
  		length = task_has_security(current, SECURITY__SETENFORCE);
  		if (length)
  			goto out;
  		audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
  			"enforcing=%d old_enforcing=%d auid=%u ses=%u",
  			new_value, selinux_enforcing,
  			audit_get_loginuid(current),
  			audit_get_sessionid(current));
  		selinux_enforcing = new_value;
  		if (selinux_enforcing)
  			avc_ss_reset(0);
  		selnl_notify_setenforce(selinux_enforcing);
  		selinux_status_update_setenforce(selinux_enforcing);
  	}
  	length = count;
  out:
  	free_page((unsigned long) page);
  	return length;
  }
  #else
  #define sel_write_enforce NULL
  #endif
  
  static const struct file_operations sel_enforce_ops = {
  	.read		= sel_read_enforce,
  	.write		= sel_write_enforce,
  	.llseek		= generic_file_llseek,
  };
  
  static ssize_t sel_read_handle_unknown(struct file *filp, char __user *buf,
  					size_t count, loff_t *ppos)
  {
  	char tmpbuf[TMPBUFLEN];
  	ssize_t length;
  	ino_t ino = filp->f_path.dentry->d_inode->i_ino;
  	int handle_unknown = (ino == SEL_REJECT_UNKNOWN) ?
  		security_get_reject_unknown() : !security_get_allow_unknown();
  
  	length = scnprintf(tmpbuf, TMPBUFLEN, "%d", handle_unknown);
  	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
  }
  
  static const struct file_operations sel_handle_unknown_ops = {
  	.read		= sel_read_handle_unknown,
  	.llseek		= generic_file_llseek,
  };
  
  static int sel_open_handle_status(struct inode *inode, struct file *filp)
  {
  	struct page    *status = selinux_kernel_status_page();
  
  	if (!status)
  		return -ENOMEM;
  
  	filp->private_data = status;
  
  	return 0;
  }
  
  static ssize_t sel_read_handle_status(struct file *filp, char __user *buf,
  				      size_t count, loff_t *ppos)
  {
  	struct page    *status = filp->private_data;
  
  	BUG_ON(!status);
  
  	return simple_read_from_buffer(buf, count, ppos,
  				       page_address(status),
  				       sizeof(struct selinux_kernel_status));
  }
  
  static int sel_mmap_handle_status(struct file *filp,
  				  struct vm_area_struct *vma)
  {
  	struct page    *status = filp->private_data;
  	unsigned long	size = vma->vm_end - vma->vm_start;
  
  	BUG_ON(!status);
  
  	/* only allows one page from the head */
  	if (vma->vm_pgoff > 0 || size != PAGE_SIZE)
  		return -EIO;
  	/* disallow writable mapping */
  	if (vma->vm_flags & VM_WRITE)
  		return -EPERM;
  	/* disallow mprotect() turns it into writable */
  	vma->vm_flags &= ~VM_MAYWRITE;
  
  	return remap_pfn_range(vma, vma->vm_start,
  			       page_to_pfn(status),
  			       size, vma->vm_page_prot);
  }
  
  static const struct file_operations sel_handle_status_ops = {
  	.open		= sel_open_handle_status,
  	.read		= sel_read_handle_status,
  	.mmap		= sel_mmap_handle_status,
  	.llseek		= generic_file_llseek,
  };
  
  #ifdef CONFIG_SECURITY_SELINUX_DISABLE
  static ssize_t sel_write_disable(struct file *file, const char __user *buf,
  				 size_t count, loff_t *ppos)
  
  {
  	char *page = NULL;
  	ssize_t length;
  	int new_value;
  	extern int selinux_disable(void);
  
  	length = -ENOMEM;
  	if (count >= PAGE_SIZE)
  		goto out;
  
  	/* No partial writes. */
  	length = -EINVAL;
  	if (*ppos != 0)
  		goto out;
  
  	length = -ENOMEM;
  	page = (char *)get_zeroed_page(GFP_KERNEL);
  	if (!page)
  		goto out;
  
  	length = -EFAULT;
  	if (copy_from_user(page, buf, count))
  		goto out;
  
  	length = -EINVAL;
  	if (sscanf(page, "%d", &new_value) != 1)
  		goto out;
  
  	if (new_value) {
  		length = selinux_disable();
  		if (length)
  			goto out;
  		audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_STATUS,
  			"selinux=0 auid=%u ses=%u",
  			audit_get_loginuid(current),
  			audit_get_sessionid(current));
  	}
  
  	length = count;
  out:
  	free_page((unsigned long) page);
  	return length;
  }
  #else
  #define sel_write_disable NULL
  #endif
  
  static const struct file_operations sel_disable_ops = {
  	.write		= sel_write_disable,
  	.llseek		= generic_file_llseek,
  };
  
  static ssize_t sel_read_policyvers(struct file *filp, char __user *buf,
  				   size_t count, loff_t *ppos)
  {
  	char tmpbuf[TMPBUFLEN];
  	ssize_t length;
  
  	length = scnprintf(tmpbuf, TMPBUFLEN, "%u", POLICYDB_VERSION_MAX);
  	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
  }
  
  static const struct file_operations sel_policyvers_ops = {
  	.read		= sel_read_policyvers,
  	.llseek		= generic_file_llseek,
  };
  
  /* declaration for sel_write_load */
  static int sel_make_bools(void);
  static int sel_make_classes(void);
  static int sel_make_policycap(void);
  
  /* declaration for sel_make_class_dirs */
  static int sel_make_dir(struct inode *dir, struct dentry *dentry,
  			unsigned long *ino);
  
  static ssize_t sel_read_mls(struct file *filp, char __user *buf,
  				size_t count, loff_t *ppos)
  {
  	char tmpbuf[TMPBUFLEN];
  	ssize_t length;
  
  	length = scnprintf(tmpbuf, TMPBUFLEN, "%d",
  			   security_mls_enabled());
  	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
  }
  
  static const struct file_operations sel_mls_ops = {
  	.read		= sel_read_mls,
  	.llseek		= generic_file_llseek,
  };
  
  struct policy_load_memory {
  	size_t len;
  	void *data;
  };
  
  static int sel_open_policy(struct inode *inode, struct file *filp)
  {
  	struct policy_load_memory *plm = NULL;
  	int rc;
  
  	BUG_ON(filp->private_data);
  
  	mutex_lock(&sel_mutex);
  
  	rc = task_has_security(current, SECURITY__READ_POLICY);
  	if (rc)
  		goto err;
  
  	rc = -EBUSY;
  	if (policy_opened)
  		goto err;
  
  	rc = -ENOMEM;
  	plm = kzalloc(sizeof(*plm), GFP_KERNEL);
  	if (!plm)
  		goto err;
  
  	if (i_size_read(inode) != security_policydb_len()) {
  		mutex_lock(&inode->i_mutex);
  		i_size_write(inode, security_policydb_len());
  		mutex_unlock(&inode->i_mutex);
  	}
  
  	rc = security_read_policy(&plm->data, &plm->len);
  	if (rc)
  		goto err;
  
  	policy_opened = 1;
  
  	filp->private_data = plm;
  
  	mutex_unlock(&sel_mutex);
  
  	return 0;
  err:
  	mutex_unlock(&sel_mutex);
  
  	if (plm)
  		vfree(plm->data);
  	kfree(plm);
  	return rc;
  }
  
  static int sel_release_policy(struct inode *inode, struct file *filp)
  {
  	struct policy_load_memory *plm = filp->private_data;
  
  	BUG_ON(!plm);
  
  	policy_opened = 0;
  
  	vfree(plm->data);
  	kfree(plm);
  
  	return 0;
  }
  
  static ssize_t sel_read_policy(struct file *filp, char __user *buf,
  			       size_t count, loff_t *ppos)
  {
  	struct policy_load_memory *plm = filp->private_data;
  	int ret;
  
  	mutex_lock(&sel_mutex);
  
  	ret = task_has_security(current, SECURITY__READ_POLICY);
  	if (ret)
  		goto out;
  
  	ret = simple_read_from_buffer(buf, count, ppos, plm->data, plm->len);
  out:
  	mutex_unlock(&sel_mutex);
  	return ret;
  }
  
  static int sel_mmap_policy_fault(struct vm_area_struct *vma,
  				 struct vm_fault *vmf)
  {
  	struct policy_load_memory *plm = vma->vm_file->private_data;
  	unsigned long offset;
  	struct page *page;
  
  	if (vmf->flags & (FAULT_FLAG_MKWRITE | FAULT_FLAG_WRITE))
  		return VM_FAULT_SIGBUS;
  
  	offset = vmf->pgoff << PAGE_SHIFT;
  	if (offset >= roundup(plm->len, PAGE_SIZE))
  		return VM_FAULT_SIGBUS;
  
  	page = vmalloc_to_page(plm->data + offset);
  	get_page(page);
  
  	vmf->page = page;
  
  	return 0;
  }
  
  static struct vm_operations_struct sel_mmap_policy_ops = {
  	.fault = sel_mmap_policy_fault,
  	.page_mkwrite = sel_mmap_policy_fault,
  };
  
  int sel_mmap_policy(struct file *filp, struct vm_area_struct *vma)
  {
  	if (vma->vm_flags & VM_SHARED) {
  		/* do not allow mprotect to make mapping writable */
  		vma->vm_flags &= ~VM_MAYWRITE;
  
  		if (vma->vm_flags & VM_WRITE)
  			return -EACCES;
  	}
  
  	vma->vm_flags |= VM_RESERVED;
  	vma->vm_ops = &sel_mmap_policy_ops;
  
  	return 0;
  }
  
  static const struct file_operations sel_policy_ops = {
  	.open		= sel_open_policy,
  	.read		= sel_read_policy,
  	.mmap		= sel_mmap_policy,
  	.release	= sel_release_policy,
  };
  
  static ssize_t sel_write_load(struct file *file, const char __user *buf,
  			      size_t count, loff_t *ppos)
  
  {
  	ssize_t length;
  	void *data = NULL;
  
  	mutex_lock(&sel_mutex);
  
  	length = task_has_security(current, SECURITY__LOAD_POLICY);
  	if (length)
  		goto out;
  
  	/* No partial writes. */
  	length = -EINVAL;
  	if (*ppos != 0)
  		goto out;
  
  	length = -EFBIG;
  	if (count > 64 * 1024 * 1024)
  		goto out;
  
  	length = -ENOMEM;
  	data = vmalloc(count);
  	if (!data)
  		goto out;
  
  	length = -EFAULT;
  	if (copy_from_user(data, buf, count) != 0)
  		goto out;
  
  	length = security_load_policy(data, count);
  	if (length)
  		goto out;
  
  	length = sel_make_bools();
  	if (length)
  		goto out1;
  
  	length = sel_make_classes();
  	if (length)
  		goto out1;
  
  	length = sel_make_policycap();
  	if (length)
  		goto out1;
  
  	length = count;
  
  out1:
  	audit_log(current->audit_context, GFP_KERNEL, AUDIT_MAC_POLICY_LOAD,
  		"policy loaded auid=%u ses=%u",
  		audit_get_loginuid(current),
  		audit_get_sessionid(current));
  out:
  	mutex_unlock(&sel_mutex);
  	vfree(data);
  	return length;
  }
  
  static const struct file_operations sel_load_ops = {
  	.write		= sel_write_load,
  	.llseek		= generic_file_llseek,
  };
  
  static ssize_t sel_write_context(struct file *file, char *buf, size_t size)
  {
  	char *canon = NULL;
  	u32 sid, len;
  	ssize_t length;
  
  	length = task_has_security(current, SECURITY__CHECK_CONTEXT);
  	if (length)
  		goto out;
  
  	length = security_context_to_sid(buf, size, &sid);
  	if (length)
  		goto out;
  
  	length = security_sid_to_context(sid, &canon, &len);
  	if (length)
  		goto out;
  
  	length = -ERANGE;
  	if (len > SIMPLE_TRANSACTION_LIMIT) {
  		printk(KERN_ERR "SELinux: %s:  context size (%u) exceeds "
  			"payload max\n", __func__, len);
  		goto out;
  	}
  
  	memcpy(buf, canon, len);
  	length = len;
  out:
  	kfree(canon);
  	return length;
  }
  
  static ssize_t sel_read_checkreqprot(struct file *filp, char __user *buf,
  				     size_t count, loff_t *ppos)
  {
  	char tmpbuf[TMPBUFLEN];
  	ssize_t length;
  
  	length = scnprintf(tmpbuf, TMPBUFLEN, "%u", selinux_checkreqprot);
  	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
  }
  
  static ssize_t sel_write_checkreqprot(struct file *file, const char __user *buf,
  				      size_t count, loff_t *ppos)
  {
  	char *page = NULL;
  	ssize_t length;
  	unsigned int new_value;
  
  	length = task_has_security(current, SECURITY__SETCHECKREQPROT);
  	if (length)
  		goto out;
  
  	length = -ENOMEM;
  	if (count >= PAGE_SIZE)
  		goto out;
  
  	/* No partial writes. */
  	length = -EINVAL;
  	if (*ppos != 0)
  		goto out;
  
  	length = -ENOMEM;
  	page = (char *)get_zeroed_page(GFP_KERNEL);
  	if (!page)
  		goto out;
  
  	length = -EFAULT;
  	if (copy_from_user(page, buf, count))
  		goto out;
  
  	length = -EINVAL;
  	if (sscanf(page, "%u", &new_value) != 1)
  		goto out;
  
  	selinux_checkreqprot = new_value ? 1 : 0;
  	length = count;
  out:
  	free_page((unsigned long) page);
  	return length;
  }
  static const struct file_operations sel_checkreqprot_ops = {
  	.read		= sel_read_checkreqprot,
  	.write		= sel_write_checkreqprot,
  	.llseek		= generic_file_llseek,
  };
  
  /*
   * Remaining nodes use transaction based IO methods like nfsd/nfsctl.c
   */
  static ssize_t sel_write_access(struct file *file, char *buf, size_t size);
  static ssize_t sel_write_create(struct file *file, char *buf, size_t size);
  static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size);
  static ssize_t sel_write_user(struct file *file, char *buf, size_t size);
  static ssize_t sel_write_member(struct file *file, char *buf, size_t size);
  
  static ssize_t (*write_op[])(struct file *, char *, size_t) = {
  	[SEL_ACCESS] = sel_write_access,
  	[SEL_CREATE] = sel_write_create,
  	[SEL_RELABEL] = sel_write_relabel,
  	[SEL_USER] = sel_write_user,
  	[SEL_MEMBER] = sel_write_member,
  	[SEL_CONTEXT] = sel_write_context,
  };
  
  static ssize_t selinux_transaction_write(struct file *file, const char __user *buf, size_t size, loff_t *pos)
  {
  	ino_t ino = file->f_path.dentry->d_inode->i_ino;
  	char *data;
  	ssize_t rv;
  
  	if (ino >= ARRAY_SIZE(write_op) || !write_op[ino])
  		return -EINVAL;
  
  	data = simple_transaction_get(file, buf, size);
  	if (IS_ERR(data))
  		return PTR_ERR(data);
  
  	rv = write_op[ino](file, data, size);
  	if (rv > 0) {
  		simple_transaction_set(file, rv);
  		rv = size;
  	}
  	return rv;
  }
  
  static const struct file_operations transaction_ops = {
  	.write		= selinux_transaction_write,
  	.read		= simple_transaction_read,
  	.release	= simple_transaction_release,
  	.llseek		= generic_file_llseek,
  };
  
  /*
   * payload - write methods
   * If the method has a response, the response should be put in buf,
   * and the length returned.  Otherwise return 0 or and -error.
   */
  
  static ssize_t sel_write_access(struct file *file, char *buf, size_t size)
  {
  	char *scon = NULL, *tcon = NULL;
  	u32 ssid, tsid;
  	u16 tclass;
  	struct av_decision avd;
  	ssize_t length;
  
  	length = task_has_security(current, SECURITY__COMPUTE_AV);
  	if (length)
  		goto out;
  
  	length = -ENOMEM;
  	scon = kzalloc(size + 1, GFP_KERNEL);
  	if (!scon)
  		goto out;
  
  	length = -ENOMEM;
  	tcon = kzalloc(size + 1, GFP_KERNEL);
  	if (!tcon)
  		goto out;
  
  	length = -EINVAL;
  	if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
  		goto out;
  
  	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid);
  	if (length)
  		goto out;
  
  	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid);
  	if (length)
  		goto out;
  
  	security_compute_av_user(ssid, tsid, tclass, &avd);
  
  	length = scnprintf(buf, SIMPLE_TRANSACTION_LIMIT,
  			  "%x %x %x %x %u %x",
  			  avd.allowed, 0xffffffff,
  			  avd.auditallow, avd.auditdeny,
  			  avd.seqno, avd.flags);
  out:
  	kfree(tcon);
  	kfree(scon);
  	return length;
  }
  
  static inline int hexcode_to_int(int code) {
  	if (code == '\0' || !isxdigit(code))
  		return -1;
  	if (isdigit(code))
  		return code - '0';
  	return tolower(code) - 'a' + 10;
  }
  
  static ssize_t sel_write_create(struct file *file, char *buf, size_t size)
  {
  	char *scon = NULL, *tcon = NULL;
  	char *namebuf = NULL, *objname = NULL;
  	u32 ssid, tsid, newsid;
  	u16 tclass;
  	ssize_t length;
  	char *newcon = NULL;
  	u32 len;
  	int nargs;
  
  	length = task_has_security(current, SECURITY__COMPUTE_CREATE);
  	if (length)
  		goto out;
  
  	length = -ENOMEM;
  	scon = kzalloc(size + 1, GFP_KERNEL);
  	if (!scon)
  		goto out;
  
  	length = -ENOMEM;
  	tcon = kzalloc(size + 1, GFP_KERNEL);
  	if (!tcon)
  		goto out;
  
  	length = -ENOMEM;
  	namebuf = kzalloc(size + 1, GFP_KERNEL);
  	if (!namebuf)
  		goto out;
  
  	length = -EINVAL;
  	nargs = sscanf(buf, "%s %s %hu %s", scon, tcon, &tclass, namebuf);
  	if (nargs < 3 || nargs > 4)
  		goto out;
  	if (nargs == 4) {
  		/*
  		 * If and when the name of new object to be queried contains
  		 * either whitespace or multibyte characters, they shall be
  		 * encoded based on the percentage-encoding rule.
  		 * If not encoded, the sscanf logic picks up only left-half
  		 * of the supplied name; splitted by a whitespace unexpectedly.
  		 */
  		char   *r, *w;
  		int     c1, c2;
  
  		r = w = namebuf;
  		do {
  			c1 = *r++;
  			if (c1 == '+')
  				c1 = ' ';
  			else if (c1 == '%') {
  				if ((c1 = hexcode_to_int(*r++)) < 0)
  					goto out;
  				if ((c2 = hexcode_to_int(*r++)) < 0)
  					goto out;
  				c1 = (c1 << 4) | c2;
  			}
  			*w++ = c1;
  		} while (c1 != '\0');
  
  		objname = namebuf;
  	}
  
  	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid);
  	if (length)
  		goto out;
  
  	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid);
  	if (length)
  		goto out;
  
  	length = security_transition_sid_user(ssid, tsid, tclass,
  					      objname, &newsid);
  	if (length)
  		goto out;
  
  	length = security_sid_to_context(newsid, &newcon, &len);
  	if (length)
  		goto out;
  
  	length = -ERANGE;
  	if (len > SIMPLE_TRANSACTION_LIMIT) {
  		printk(KERN_ERR "SELinux: %s:  context size (%u) exceeds "
  			"payload max\n", __func__, len);
  		goto out;
  	}
  
  	memcpy(buf, newcon, len);
  	length = len;
  out:
  	kfree(newcon);
  	kfree(namebuf);
  	kfree(tcon);
  	kfree(scon);
  	return length;
  }
  
  static ssize_t sel_write_relabel(struct file *file, char *buf, size_t size)
  {
  	char *scon = NULL, *tcon = NULL;
  	u32 ssid, tsid, newsid;
  	u16 tclass;
  	ssize_t length;
  	char *newcon = NULL;
  	u32 len;
  
  	length = task_has_security(current, SECURITY__COMPUTE_RELABEL);
  	if (length)
  		goto out;
  
  	length = -ENOMEM;
  	scon = kzalloc(size + 1, GFP_KERNEL);
  	if (!scon)
  		goto out;
  
  	length = -ENOMEM;
  	tcon = kzalloc(size + 1, GFP_KERNEL);
  	if (!tcon)
  		goto out;
  
  	length = -EINVAL;
  	if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
  		goto out;
  
  	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid);
  	if (length)
  		goto out;
  
  	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid);
  	if (length)
  		goto out;
  
  	length = security_change_sid(ssid, tsid, tclass, &newsid);
  	if (length)
  		goto out;
  
  	length = security_sid_to_context(newsid, &newcon, &len);
  	if (length)
  		goto out;
  
  	length = -ERANGE;
  	if (len > SIMPLE_TRANSACTION_LIMIT)
  		goto out;
  
  	memcpy(buf, newcon, len);
  	length = len;
  out:
  	kfree(newcon);
  	kfree(tcon);
  	kfree(scon);
  	return length;
  }
  
  static ssize_t sel_write_user(struct file *file, char *buf, size_t size)
  {
  	char *con = NULL, *user = NULL, *ptr;
  	u32 sid, *sids = NULL;
  	ssize_t length;
  	char *newcon;
  	int i, rc;
  	u32 len, nsids;
  
  	length = task_has_security(current, SECURITY__COMPUTE_USER);
  	if (length)
  		goto out;
  
  	length = -ENOMEM;
  	con = kzalloc(size + 1, GFP_KERNEL);
  	if (!con)
  		goto out;
  
  	length = -ENOMEM;
  	user = kzalloc(size + 1, GFP_KERNEL);
  	if (!user)
  		goto out;
  
  	length = -EINVAL;
  	if (sscanf(buf, "%s %s", con, user) != 2)
  		goto out;
  
  	length = security_context_to_sid(con, strlen(con) + 1, &sid);
  	if (length)
  		goto out;
  
  	length = security_get_user_sids(sid, user, &sids, &nsids);
  	if (length)
  		goto out;
  
  	length = sprintf(buf, "%u", nsids) + 1;
  	ptr = buf + length;
  	for (i = 0; i < nsids; i++) {
  		rc = security_sid_to_context(sids[i], &newcon, &len);
  		if (rc) {
  			length = rc;
  			goto out;
  		}
  		if ((length + len) >= SIMPLE_TRANSACTION_LIMIT) {
  			kfree(newcon);
  			length = -ERANGE;
  			goto out;
  		}
  		memcpy(ptr, newcon, len);
  		kfree(newcon);
  		ptr += len;
  		length += len;
  	}
  out:
  	kfree(sids);
  	kfree(user);
  	kfree(con);
  	return length;
  }
  
  static ssize_t sel_write_member(struct file *file, char *buf, size_t size)
  {
  	char *scon = NULL, *tcon = NULL;
  	u32 ssid, tsid, newsid;
  	u16 tclass;
  	ssize_t length;
  	char *newcon = NULL;
  	u32 len;
  
  	length = task_has_security(current, SECURITY__COMPUTE_MEMBER);
  	if (length)
  		goto out;
  
  	length = -ENOMEM;
  	scon = kzalloc(size + 1, GFP_KERNEL);
  	if (!scon)
  		goto out;
  
  	length = -ENOMEM;
  	tcon = kzalloc(size + 1, GFP_KERNEL);
  	if (!tcon)
  		goto out;
  
  	length = -EINVAL;
  	if (sscanf(buf, "%s %s %hu", scon, tcon, &tclass) != 3)
  		goto out;
  
  	length = security_context_to_sid(scon, strlen(scon) + 1, &ssid);
  	if (length)
  		goto out;
  
  	length = security_context_to_sid(tcon, strlen(tcon) + 1, &tsid);
  	if (length)
  		goto out;
  
  	length = security_member_sid(ssid, tsid, tclass, &newsid);
  	if (length)
  		goto out;
  
  	length = security_sid_to_context(newsid, &newcon, &len);
  	if (length)
  		goto out;
  
  	length = -ERANGE;
  	if (len > SIMPLE_TRANSACTION_LIMIT) {
  		printk(KERN_ERR "SELinux: %s:  context size (%u) exceeds "
  			"payload max\n", __func__, len);
  		goto out;
  	}
  
  	memcpy(buf, newcon, len);
  	length = len;
  out:
  	kfree(newcon);
  	kfree(tcon);
  	kfree(scon);
  	return length;
  }
  
  static struct inode *sel_make_inode(struct super_block *sb, int mode)
  {
  	struct inode *ret = new_inode(sb);
  
  	if (ret) {
  		ret->i_mode = mode;
  		ret->i_atime = ret->i_mtime = ret->i_ctime = CURRENT_TIME;
  	}
  	return ret;
  }
  
  static ssize_t sel_read_bool(struct file *filep, char __user *buf,
  			     size_t count, loff_t *ppos)
  {
  	char *page = NULL;
  	ssize_t length;
  	ssize_t ret;
  	int cur_enforcing;
  	struct inode *inode = filep->f_path.dentry->d_inode;
  	unsigned index = inode->i_ino & SEL_INO_MASK;
  	const char *name = filep->f_path.dentry->d_name.name;
  
  	mutex_lock(&sel_mutex);
  
  	ret = -EINVAL;
  	if (index >= bool_num || strcmp(name, bool_pending_names[index]))
  		goto out;
  
  	ret = -ENOMEM;
  	page = (char *)get_zeroed_page(GFP_KERNEL);
  	if (!page)
  		goto out;
  
  	cur_enforcing = security_get_bool_value(index);
  	if (cur_enforcing < 0) {
  		ret = cur_enforcing;
  		goto out;
  	}
  	length = scnprintf(page, PAGE_SIZE, "%d %d", cur_enforcing,
  			  bool_pending_values[index]);
  	ret = simple_read_from_buffer(buf, count, ppos, page, length);
  out:
  	mutex_unlock(&sel_mutex);
  	free_page((unsigned long)page);
  	return ret;
  }
  
  static ssize_t sel_write_bool(struct file *filep, const char __user *buf,
  			      size_t count, loff_t *ppos)
  {
  	char *page = NULL;
  	ssize_t length;
  	int new_value;
  	struct inode *inode = filep->f_path.dentry->d_inode;
  	unsigned index = inode->i_ino & SEL_INO_MASK;
  	const char *name = filep->f_path.dentry->d_name.name;
  
  	mutex_lock(&sel_mutex);
  
  	length = task_has_security(current, SECURITY__SETBOOL);
  	if (length)
  		goto out;
  
  	length = -EINVAL;
  	if (index >= bool_num || strcmp(name, bool_pending_names[index]))
  		goto out;
  
  	length = -ENOMEM;
  	if (count >= PAGE_SIZE)
  		goto out;
  
  	/* No partial writes. */
  	length = -EINVAL;
  	if (*ppos != 0)
  		goto out;
  
  	length = -ENOMEM;
  	page = (char *)get_zeroed_page(GFP_KERNEL);
  	if (!page)
  		goto out;
  
  	length = -EFAULT;
  	if (copy_from_user(page, buf, count))
  		goto out;
  
  	length = -EINVAL;
  	if (sscanf(page, "%d", &new_value) != 1)
  		goto out;
  
  	if (new_value)
  		new_value = 1;
  
  	bool_pending_values[index] = new_value;
  	length = count;
  
  out:
  	mutex_unlock(&sel_mutex);
  	free_page((unsigned long) page);
  	return length;
  }
  
  static const struct file_operations sel_bool_ops = {
  	.read		= sel_read_bool,
  	.write		= sel_write_bool,
  	.llseek		= generic_file_llseek,
  };
  
  static ssize_t sel_commit_bools_write(struct file *filep,
  				      const char __user *buf,
  				      size_t count, loff_t *ppos)
  {
  	char *page = NULL;
  	ssize_t length;
  	int new_value;
  
  	mutex_lock(&sel_mutex);
  
  	length = task_has_security(current, SECURITY__SETBOOL);
  	if (length)
  		goto out;
  
  	length = -ENOMEM;
  	if (count >= PAGE_SIZE)
  		goto out;
  
  	/* No partial writes. */
  	length = -EINVAL;
  	if (*ppos != 0)
  		goto out;
  
  	length = -ENOMEM;
  	page = (char *)get_zeroed_page(GFP_KERNEL);
  	if (!page)
  		goto out;
  
  	length = -EFAULT;
  	if (copy_from_user(page, buf, count))
  		goto out;
  
  	length = -EINVAL;
  	if (sscanf(page, "%d", &new_value) != 1)
  		goto out;
  
  	length = 0;
  	if (new_value && bool_pending_values)
  		length = security_set_bools(bool_num, bool_pending_values);
  
  	if (!length)
  		length = count;
  
  out:
  	mutex_unlock(&sel_mutex);
  	free_page((unsigned long) page);
  	return length;
  }
  
  static const struct file_operations sel_commit_bools_ops = {
  	.write		= sel_commit_bools_write,
  	.llseek		= generic_file_llseek,
  };
  
  static void sel_remove_entries(struct dentry *de)
  {
  	struct list_head *node;
  
  	spin_lock(&de->d_lock);
  	node = de->d_subdirs.next;
  	while (node != &de->d_subdirs) {
  		struct dentry *d = list_entry(node, struct dentry, d_u.d_child);
  
  		spin_lock_nested(&d->d_lock, DENTRY_D_LOCK_NESTED);
  		list_del_init(node);
  
  		if (d->d_inode) {
  			dget_dlock(d);
  			spin_unlock(&de->d_lock);
  			spin_unlock(&d->d_lock);
  			d_delete(d);
  			simple_unlink(de->d_inode, d);
  			dput(d);
  			spin_lock(&de->d_lock);
  		} else
  			spin_unlock(&d->d_lock);
  		node = de->d_subdirs.next;
  	}
  
  	spin_unlock(&de->d_lock);
  }
  
  #define BOOL_DIR_NAME "booleans"
  
  static int sel_make_bools(void)
  {
  	int i, ret;
  	ssize_t len;
  	struct dentry *dentry = NULL;
  	struct dentry *dir = bool_dir;
  	struct inode *inode = NULL;
  	struct inode_security_struct *isec;
  	char **names = NULL, *page;
  	int num;
  	int *values = NULL;
  	u32 sid;
  
  	/* remove any existing files */
  	for (i = 0; i < bool_num; i++)
  		kfree(bool_pending_names[i]);
  	kfree(bool_pending_names);
  	kfree(bool_pending_values);
  	bool_pending_names = NULL;
  	bool_pending_values = NULL;
  
  	sel_remove_entries(dir);
  
  	ret = -ENOMEM;
  	page = (char *)get_zeroed_page(GFP_KERNEL);
  	if (!page)
  		goto out;
  
  	ret = security_get_bools(&num, &names, &values);
  	if (ret)
  		goto out;
  
  	for (i = 0; i < num; i++) {
  		ret = -ENOMEM;
  		dentry = d_alloc_name(dir, names[i]);
  		if (!dentry)
  			goto out;
  
  		ret = -ENOMEM;
  		inode = sel_make_inode(dir->d_sb, S_IFREG | S_IRUGO | S_IWUSR);
  		if (!inode)
  			goto out;
  
  		ret = -EINVAL;
  		len = snprintf(page, PAGE_SIZE, "/%s/%s", BOOL_DIR_NAME, names[i]);
  		if (len < 0)
  			goto out;
  
  		ret = -ENAMETOOLONG;
  		if (len >= PAGE_SIZE)
  			goto out;
  
  		isec = (struct inode_security_struct *)inode->i_security;
  		ret = security_genfs_sid("selinuxfs", page, SECCLASS_FILE, &sid);
  		if (ret)
  			goto out;
  
  		isec->sid = sid;
  		isec->initialized = 1;
  		inode->i_fop = &sel_bool_ops;
  		inode->i_ino = i|SEL_BOOL_INO_OFFSET;
  		d_add(dentry, inode);
  	}
  	bool_num = num;
  	bool_pending_names = names;
  	bool_pending_values = values;
  
  	free_page((unsigned long)page);
  	return 0;
  out:
  	free_page((unsigned long)page);
  
  	if (names) {
  		for (i = 0; i < num; i++)
  			kfree(names[i]);
  		kfree(names);
  	}
  	kfree(values);
  	sel_remove_entries(dir);
  
  	return ret;
  }
  
  #define NULL_FILE_NAME "null"
  
  struct dentry *selinux_null;
  
  static ssize_t sel_read_avc_cache_threshold(struct file *filp, char __user *buf,
  					    size_t count, loff_t *ppos)
  {
  	char tmpbuf[TMPBUFLEN];
  	ssize_t length;
  
  	length = scnprintf(tmpbuf, TMPBUFLEN, "%u", avc_cache_threshold);
  	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
  }
  
  static ssize_t sel_write_avc_cache_threshold(struct file *file,
  					     const char __user *buf,
  					     size_t count, loff_t *ppos)
  
  {
  	char *page = NULL;
  	ssize_t ret;
  	int new_value;
  
  	ret = task_has_security(current, SECURITY__SETSECPARAM);
  	if (ret)
  		goto out;
  
  	ret = -ENOMEM;
  	if (count >= PAGE_SIZE)
  		goto out;
  
  	/* No partial writes. */
  	ret = -EINVAL;
  	if (*ppos != 0)
  		goto out;
  
  	ret = -ENOMEM;
  	page = (char *)get_zeroed_page(GFP_KERNEL);
  	if (!page)
  		goto out;
  
  	ret = -EFAULT;
  	if (copy_from_user(page, buf, count))
  		goto out;
  
  	ret = -EINVAL;
  	if (sscanf(page, "%u", &new_value) != 1)
  		goto out;
  
  	avc_cache_threshold = new_value;
  
  	ret = count;
  out:
  	free_page((unsigned long)page);
  	return ret;
  }
  
  static ssize_t sel_read_avc_hash_stats(struct file *filp, char __user *buf,
  				       size_t count, loff_t *ppos)
  {
  	char *page;
  	ssize_t length;
  
  	page = (char *)__get_free_page(GFP_KERNEL);
  	if (!page)
  		return -ENOMEM;
  
  	length = avc_get_hash_stats(page);
  	if (length >= 0)
  		length = simple_read_from_buffer(buf, count, ppos, page, length);
  	free_page((unsigned long)page);
  
  	return length;
  }
  
  static const struct file_operations sel_avc_cache_threshold_ops = {
  	.read		= sel_read_avc_cache_threshold,
  	.write		= sel_write_avc_cache_threshold,
  	.llseek		= generic_file_llseek,
  };
  
  static const struct file_operations sel_avc_hash_stats_ops = {
  	.read		= sel_read_avc_hash_stats,
  	.llseek		= generic_file_llseek,
  };
  
  #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
  static struct avc_cache_stats *sel_avc_get_stat_idx(loff_t *idx)
  {
  	int cpu;
  
  	for (cpu = *idx; cpu < nr_cpu_ids; ++cpu) {
  		if (!cpu_possible(cpu))
  			continue;
  		*idx = cpu + 1;
  		return &per_cpu(avc_cache_stats, cpu);
  	}
  	return NULL;
  }
  
  static void *sel_avc_stats_seq_start(struct seq_file *seq, loff_t *pos)
  {
  	loff_t n = *pos - 1;
  
  	if (*pos == 0)
  		return SEQ_START_TOKEN;
  
  	return sel_avc_get_stat_idx(&n);
  }
  
  static void *sel_avc_stats_seq_next(struct seq_file *seq, void *v, loff_t *pos)
  {
  	return sel_avc_get_stat_idx(pos);
  }
  
  static int sel_avc_stats_seq_show(struct seq_file *seq, void *v)
  {
  	struct avc_cache_stats *st = v;
  
  	if (v == SEQ_START_TOKEN)
  		seq_printf(seq, "lookups hits misses allocations reclaims "
  			   "frees\n");
  	else {
  		unsigned int lookups = st->lookups;
  		unsigned int misses = st->misses;
  		unsigned int hits = lookups - misses;
  		seq_printf(seq, "%u %u %u %u %u %u\n", lookups,
  			   hits, misses, st->allocations,
  			   st->reclaims, st->frees);
  	}
  	return 0;
  }
  
  static void sel_avc_stats_seq_stop(struct seq_file *seq, void *v)
  { }
  
  static const struct seq_operations sel_avc_cache_stats_seq_ops = {
  	.start		= sel_avc_stats_seq_start,
  	.next		= sel_avc_stats_seq_next,
  	.show		= sel_avc_stats_seq_show,
  	.stop		= sel_avc_stats_seq_stop,
  };
  
  static int sel_open_avc_cache_stats(struct inode *inode, struct file *file)
  {
  	return seq_open(file, &sel_avc_cache_stats_seq_ops);
  }
  
  static const struct file_operations sel_avc_cache_stats_ops = {
  	.open		= sel_open_avc_cache_stats,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= seq_release,
  };
  #endif
  
  static int sel_make_avc_files(struct dentry *dir)
  {
  	int i;
  	static struct tree_descr files[] = {
  		{ "cache_threshold",
  		  &sel_avc_cache_threshold_ops, S_IRUGO|S_IWUSR },
  		{ "hash_stats", &sel_avc_hash_stats_ops, S_IRUGO },
  #ifdef CONFIG_SECURITY_SELINUX_AVC_STATS
  		{ "cache_stats", &sel_avc_cache_stats_ops, S_IRUGO },
  #endif
  	};
  
  	for (i = 0; i < ARRAY_SIZE(files); i++) {
  		struct inode *inode;
  		struct dentry *dentry;
  
  		dentry = d_alloc_name(dir, files[i].name);
  		if (!dentry)
  			return -ENOMEM;
  
  		inode = sel_make_inode(dir->d_sb, S_IFREG|files[i].mode);
  		if (!inode)
  			return -ENOMEM;
  
  		inode->i_fop = files[i].ops;
  		inode->i_ino = ++sel_last_ino;
  		d_add(dentry, inode);
  	}
  
  	return 0;
  }
  
  static ssize_t sel_read_initcon(struct file *file, char __user *buf,
  				size_t count, loff_t *ppos)
  {
  	struct inode *inode;
  	char *con;
  	u32 sid, len;
  	ssize_t ret;
  
  	inode = file->f_path.dentry->d_inode;
  	sid = inode->i_ino&SEL_INO_MASK;
  	ret = security_sid_to_context(sid, &con, &len);
  	if (ret)
  		return ret;
  
  	ret = simple_read_from_buffer(buf, count, ppos, con, len);
  	kfree(con);
  	return ret;
  }
  
  static const struct file_operations sel_initcon_ops = {
  	.read		= sel_read_initcon,
  	.llseek		= generic_file_llseek,
  };
  
  static int sel_make_initcon_files(struct dentry *dir)
  {
  	int i;
  
  	for (i = 1; i <= SECINITSID_NUM; i++) {
  		struct inode *inode;
  		struct dentry *dentry;
  		dentry = d_alloc_name(dir, security_get_initial_sid_context(i));
  		if (!dentry)
  			return -ENOMEM;
  
  		inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
  		if (!inode)
  			return -ENOMEM;
  
  		inode->i_fop = &sel_initcon_ops;
  		inode->i_ino = i|SEL_INITCON_INO_OFFSET;
  		d_add(dentry, inode);
  	}
  
  	return 0;
  }
  
  static inline unsigned int sel_div(unsigned long a, unsigned long b)
  {
  	return a / b - (a % b < 0);
  }
  
  static inline unsigned long sel_class_to_ino(u16 class)
  {
  	return (class * (SEL_VEC_MAX + 1)) | SEL_CLASS_INO_OFFSET;
  }
  
  static inline u16 sel_ino_to_class(unsigned long ino)
  {
  	return sel_div(ino & SEL_INO_MASK, SEL_VEC_MAX + 1);
  }
  
  static inline unsigned long sel_perm_to_ino(u16 class, u32 perm)
  {
  	return (class * (SEL_VEC_MAX + 1) + perm) | SEL_CLASS_INO_OFFSET;
  }
  
  static inline u32 sel_ino_to_perm(unsigned long ino)
  {
  	return (ino & SEL_INO_MASK) % (SEL_VEC_MAX + 1);
  }
  
  static ssize_t sel_read_class(struct file *file, char __user *buf,
  				size_t count, loff_t *ppos)
  {
  	ssize_t rc, len;
  	char *page;
  	unsigned long ino = file->f_path.dentry->d_inode->i_ino;
  
  	page = (char *)__get_free_page(GFP_KERNEL);
  	if (!page)
  		return -ENOMEM;
  
  	len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_class(ino));
  	rc = simple_read_from_buffer(buf, count, ppos, page, len);
  	free_page((unsigned long)page);
  
  	return rc;
  }
  
  static const struct file_operations sel_class_ops = {
  	.read		= sel_read_class,
  	.llseek		= generic_file_llseek,
  };
  
  static ssize_t sel_read_perm(struct file *file, char __user *buf,
  				size_t count, loff_t *ppos)
  {
  	ssize_t rc, len;
  	char *page;
  	unsigned long ino = file->f_path.dentry->d_inode->i_ino;
  
  	page = (char *)__get_free_page(GFP_KERNEL);
  	if (!page)
  		return -ENOMEM;
  
  	len = snprintf(page, PAGE_SIZE, "%d", sel_ino_to_perm(ino));
  	rc = simple_read_from_buffer(buf, count, ppos, page, len);
  	free_page((unsigned long)page);
  
  	return rc;
  }
  
  static const struct file_operations sel_perm_ops = {
  	.read		= sel_read_perm,
  	.llseek		= generic_file_llseek,
  };
  
  static ssize_t sel_read_policycap(struct file *file, char __user *buf,
  				  size_t count, loff_t *ppos)
  {
  	int value;
  	char tmpbuf[TMPBUFLEN];
  	ssize_t length;
  	unsigned long i_ino = file->f_path.dentry->d_inode->i_ino;
  
  	value = security_policycap_supported(i_ino & SEL_INO_MASK);
  	length = scnprintf(tmpbuf, TMPBUFLEN, "%d", value);
  
  	return simple_read_from_buffer(buf, count, ppos, tmpbuf, length);
  }
  
  static const struct file_operations sel_policycap_ops = {
  	.read		= sel_read_policycap,
  	.llseek		= generic_file_llseek,
  };
  
  static int sel_make_perm_files(char *objclass, int classvalue,
  				struct dentry *dir)
  {
  	int i, rc, nperms;
  	char **perms;
  
  	rc = security_get_permissions(objclass, &perms, &nperms);
  	if (rc)
  		return rc;
  
  	for (i = 0; i < nperms; i++) {
  		struct inode *inode;
  		struct dentry *dentry;
  
  		rc = -ENOMEM;
  		dentry = d_alloc_name(dir, perms[i]);
  		if (!dentry)
  			goto out;
  
  		rc = -ENOMEM;
  		inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
  		if (!inode)
  			goto out;
  
  		inode->i_fop = &sel_perm_ops;
  		/* i+1 since perm values are 1-indexed */
  		inode->i_ino = sel_perm_to_ino(classvalue, i + 1);
  		d_add(dentry, inode);
  	}
  	rc = 0;
  out:
  	for (i = 0; i < nperms; i++)
  		kfree(perms[i]);
  	kfree(perms);
  	return rc;
  }
  
  static int sel_make_class_dir_entries(char *classname, int index,
  					struct dentry *dir)
  {
  	struct dentry *dentry = NULL;
  	struct inode *inode = NULL;
  	int rc;
  
  	dentry = d_alloc_name(dir, "index");
  	if (!dentry)
  		return -ENOMEM;
  
  	inode = sel_make_inode(dir->d_sb, S_IFREG|S_IRUGO);
  	if (!inode)
  		return -ENOMEM;
  
  	inode->i_fop = &sel_class_ops;
  	inode->i_ino = sel_class_to_ino(index);
  	d_add(dentry, inode);
  
  	dentry = d_alloc_name(dir, "perms");
  	if (!dentry)
  		return -ENOMEM;
  
  	rc = sel_make_dir(dir->d_inode, dentry, &last_class_ino);
  	if (rc)
  		return rc;
  
  	rc = sel_make_perm_files(classname, index, dentry);
  
  	return rc;
  }
  
  static void sel_remove_classes(void)
  {
  	struct list_head *class_node;
  
  	list_for_each(class_node, &class_dir->d_subdirs) {
  		struct dentry *class_subdir = list_entry(class_node,
  					struct dentry, d_u.d_child);
  		struct list_head *class_subdir_node;
  
  		list_for_each(class_subdir_node, &class_subdir->d_subdirs) {
  			struct dentry *d = list_entry(class_subdir_node,
  						struct dentry, d_u.d_child);
  
  			if (d->d_inode)
  				if (d->d_inode->i_mode & S_IFDIR)
  					sel_remove_entries(d);
  		}
  
  		sel_remove_entries(class_subdir);
  	}
  
  	sel_remove_entries(class_dir);
  }
  
  static int sel_make_classes(void)
  {
  	int rc, nclasses, i;
  	char **classes;
  
  	/* delete any existing entries */
  	sel_remove_classes();
  
  	rc = security_get_classes(&classes, &nclasses);
  	if (rc)
  		return rc;
  
  	/* +2 since classes are 1-indexed */
  	last_class_ino = sel_class_to_ino(nclasses + 2);
  
  	for (i = 0; i < nclasses; i++) {
  		struct dentry *class_name_dir;
  
  		rc = -ENOMEM;
  		class_name_dir = d_alloc_name(class_dir, classes[i]);
  		if (!class_name_dir)
  			goto out;
  
  		rc = sel_make_dir(class_dir->d_inode, class_name_dir,
  				&last_class_ino);
  		if (rc)
  			goto out;
  
  		/* i+1 since class values are 1-indexed */
  		rc = sel_make_class_dir_entries(classes[i], i + 1,
  				class_name_dir);
  		if (rc)
  			goto out;
  	}
  	rc = 0;
  out:
  	for (i = 0; i < nclasses; i++)
  		kfree(classes[i]);
  	kfree(classes);
  	return rc;
  }
  
  static int sel_make_policycap(void)
  {
  	unsigned int iter;
  	struct dentry *dentry = NULL;
  	struct inode *inode = NULL;
  
  	sel_remove_entries(policycap_dir);
  
  	for (iter = 0; iter <= POLICYDB_CAPABILITY_MAX; iter++) {
  		if (iter < ARRAY_SIZE(policycap_names))
  			dentry = d_alloc_name(policycap_dir,
  					      policycap_names[iter]);
  		else
  			dentry = d_alloc_name(policycap_dir, "unknown");
  
  		if (dentry == NULL)
  			return -ENOMEM;
  
  		inode = sel_make_inode(policycap_dir->d_sb, S_IFREG | S_IRUGO);
  		if (inode == NULL)
  			return -ENOMEM;
  
  		inode->i_fop = &sel_policycap_ops;
  		inode->i_ino = iter | SEL_POLICYCAP_INO_OFFSET;
  		d_add(dentry, inode);
  	}
  
  	return 0;
  }
  
  static int sel_make_dir(struct inode *dir, struct dentry *dentry,
  			unsigned long *ino)
  {
  	struct inode *inode;
  
  	inode = sel_make_inode(dir->i_sb, S_IFDIR | S_IRUGO | S_IXUGO);
  	if (!inode)
  		return -ENOMEM;
  
  	inode->i_op = &simple_dir_inode_operations;
  	inode->i_fop = &simple_dir_operations;
  	inode->i_ino = ++(*ino);
  	/* directory inodes start off with i_nlink == 2 (for "." entry) */
  	inc_nlink(inode);
  	d_add(dentry, inode);
  	/* bump link count on parent directory, too */
  	inc_nlink(dir);
  
  	return 0;
  }
  
  static int sel_fill_super(struct super_block *sb, void *data, int silent)
  {
  	int ret;
  	struct dentry *dentry;
  	struct inode *inode, *root_inode;
  	struct inode_security_struct *isec;
  
  	static struct tree_descr selinux_files[] = {
  		[SEL_LOAD] = {"load", &sel_load_ops, S_IRUSR|S_IWUSR},
  		[SEL_ENFORCE] = {"enforce", &sel_enforce_ops, S_IRUGO|S_IWUSR},
  		[SEL_CONTEXT] = {"context", &transaction_ops, S_IRUGO|S_IWUGO},
  		[SEL_ACCESS] = {"access", &transaction_ops, S_IRUGO|S_IWUGO},
  		[SEL_CREATE] = {"create", &transaction_ops, S_IRUGO|S_IWUGO},
  		[SEL_RELABEL] = {"relabel", &transaction_ops, S_IRUGO|S_IWUGO},
  		[SEL_USER] = {"user", &transaction_ops, S_IRUGO|S_IWUGO},
  		[SEL_POLICYVERS] = {"policyvers", &sel_policyvers_ops, S_IRUGO},
  		[SEL_COMMIT_BOOLS] = {"commit_pending_bools", &sel_commit_bools_ops, S_IWUSR},
  		[SEL_MLS] = {"mls", &sel_mls_ops, S_IRUGO},
  		[SEL_DISABLE] = {"disable", &sel_disable_ops, S_IWUSR},
  		[SEL_MEMBER] = {"member", &transaction_ops, S_IRUGO|S_IWUGO},
  		[SEL_CHECKREQPROT] = {"checkreqprot", &sel_checkreqprot_ops, S_IRUGO|S_IWUSR},
  		[SEL_REJECT_UNKNOWN] = {"reject_unknown", &sel_handle_unknown_ops, S_IRUGO},
  		[SEL_DENY_UNKNOWN] = {"deny_unknown", &sel_handle_unknown_ops, S_IRUGO},
  		[SEL_STATUS] = {"status", &sel_handle_status_ops, S_IRUGO},
  		[SEL_POLICY] = {"policy", &sel_policy_ops, S_IRUSR},
  		/* last one */ {""}
  	};
  	ret = simple_fill_super(sb, SELINUX_MAGIC, selinux_files);
  	if (ret)
  		goto err;
  
  	root_inode = sb->s_root->d_inode;
  
  	ret = -ENOMEM;
  	dentry = d_alloc_name(sb->s_root, BOOL_DIR_NAME);
  	if (!dentry)
  		goto err;
  
  	ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
  	if (ret)
  		goto err;
  
  	bool_dir = dentry;
  
  	ret = -ENOMEM;
  	dentry = d_alloc_name(sb->s_root, NULL_FILE_NAME);
  	if (!dentry)
  		goto err;
  
  	ret = -ENOMEM;
  	inode = sel_make_inode(sb, S_IFCHR | S_IRUGO | S_IWUGO);
  	if (!inode)
  		goto err;
  
  	inode->i_ino = ++sel_last_ino;
  	isec = (struct inode_security_struct *)inode->i_security;
  	isec->sid = SECINITSID_DEVNULL;
  	isec->sclass = SECCLASS_CHR_FILE;
  	isec->initialized = 1;
  
  	init_special_inode(inode, S_IFCHR | S_IRUGO | S_IWUGO, MKDEV(MEM_MAJOR, 3));
  	d_add(dentry, inode);
  	selinux_null = dentry;
  
  	ret = -ENOMEM;
  	dentry = d_alloc_name(sb->s_root, "avc");
  	if (!dentry)
  		goto err;
  
  	ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
  	if (ret)
  		goto err;
  
  	ret = sel_make_avc_files(dentry);
  	if (ret)
  		goto err;
  
  	ret = -ENOMEM;
  	dentry = d_alloc_name(sb->s_root, "initial_contexts");
  	if (!dentry)
  		goto err;
  
  	ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
  	if (ret)
  		goto err;
  
  	ret = sel_make_initcon_files(dentry);
  	if (ret)
  		goto err;
  
  	ret = -ENOMEM;
  	dentry = d_alloc_name(sb->s_root, "class");
  	if (!dentry)
  		goto err;
  
  	ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
  	if (ret)
  		goto err;
  
  	class_dir = dentry;
  
  	ret = -ENOMEM;
  	dentry = d_alloc_name(sb->s_root, "policy_capabilities");
  	if (!dentry)
  		goto err;
  
  	ret = sel_make_dir(root_inode, dentry, &sel_last_ino);
  	if (ret)
  		goto err;
  
  	policycap_dir = dentry;
  
  	return 0;
  err:
  	printk(KERN_ERR "SELinux: %s:  failed while creating inodes\n",
  		__func__);
  	return ret;
  }
  
  static struct dentry *sel_mount(struct file_system_type *fs_type,
  		      int flags, const char *dev_name, void *data)
  {
  	return mount_single(fs_type, flags, data, sel_fill_super);
  }
  
  static struct file_system_type sel_fs_type = {
  	.name		= "selinuxfs",
  	.mount		= sel_mount,
  	.kill_sb	= kill_litter_super,
  };
  
  struct vfsmount *selinuxfs_mount;
  static struct kobject *selinuxfs_kobj;
  
  static int __init init_sel_fs(void)
  {
  	int err;
  
  	if (!selinux_enabled)
  		return 0;
  
  	selinuxfs_kobj = kobject_create_and_add("selinux", fs_kobj);
  	if (!selinuxfs_kobj)
  		return -ENOMEM;
  
  	err = register_filesystem(&sel_fs_type);
  	if (err) {
  		kobject_put(selinuxfs_kobj);
  		return err;
  	}
  
  	selinuxfs_mount = kern_mount(&sel_fs_type);
  	if (IS_ERR(selinuxfs_mount)) {
  		printk(KERN_ERR "selinuxfs:  could not mount!\n");
  		err = PTR_ERR(selinuxfs_mount);
  		selinuxfs_mount = NULL;
  	}
  
  	return err;
  }
  
  __initcall(init_sel_fs);
  
  #ifdef CONFIG_SECURITY_SELINUX_DISABLE
  void exit_sel_fs(void)
  {
  	kobject_put(selinuxfs_kobj);
  	unregister_filesystem(&sel_fs_type);
  }
  #endif
  