text: // SPDX-License-Identifier: GPL-2.0-only
  /*
   * AppArmor security module
   *
   * This file contains AppArmor /sys/kernel/security/apparmor interface functions
   *
   * Copyright (C) 1998-2008 Novell/SUSE
   * Copyright 2009-2010 Canonical Ltd.
   */
  
  #include <linux/ctype.h>
  #include <linux/security.h>
  #include <linux/vmalloc.h>
  #include <linux/init.h>
  #include <linux/seq_file.h>
  #include <linux/uaccess.h>
  #include <linux/mount.h>
  #include <linux/namei.h>
  #include <linux/capability.h>
  #include <linux/rcupdate.h>
  #include <linux/fs.h>
  #include <linux/poll.h>
  #include <uapi/linux/major.h>
  #include <uapi/linux/magic.h>
  
  #include "include/apparmor.h"
  #include "include/apparmorfs.h"
  #include "include/audit.h"
  #include "include/cred.h"
  #include "include/crypto.h"
  #include "include/ipc.h"
  #include "include/label.h"
  #include "include/policy.h"
  #include "include/policy_ns.h"
  #include "include/resource.h"
  #include "include/policy_unpack.h"
  
  /*
   * The apparmor filesystem interface used for policy load and introspection
   * The interface is split into two main components based on their function
   * a securityfs component:
   *   used for static files that are always available, and which allows
   *   userspace to specificy the location of the security filesystem.
   *
   *   fns and data are prefixed with
   *      aa_sfs_
   *
   * an apparmorfs component:
   *   used loaded policy content and introspection. It is not part of  a
   *   regular mounted filesystem and is available only through the magic
   *   policy symlink in the root of the securityfs apparmor/ directory.
   *   Tasks queries will be magically redirected to the correct portion
   *   of the policy tree based on their confinement.
   *
   *   fns and data are prefixed with
   *      aafs_
   *
   * The aa_fs_ prefix is used to indicate the fn is used by both the
   * securityfs and apparmorfs filesystems.
   */
  
  
  /*
   * support fns
   */
  
  /**
   * aa_mangle_name - mangle a profile name to std profile layout form
   * @name: profile name to mangle  (NOT NULL)
   * @target: buffer to store mangled name, same length as @name (MAYBE NULL)
   *
   * Returns: length of mangled name
   */
  static int mangle_name(const char *name, char *target)
  {
  	char *t = target;
  
  	while (*name == '/' || *name == '.')
  		name++;
  
  	if (target) {
  		for (; *name; name++) {
  			if (*name == '/')
  				*(t)++ = '.';
  			else if (isspace(*name))
  				*(t)++ = '_';
  			else if (isalnum(*name) || strchr("._-", *name))
  				*(t)++ = *name;
  		}
  
  		*t = 0;
  	} else {
  		int len = 0;
  		for (; *name; name++) {
  			if (isalnum(*name) || isspace(*name) ||
  			    strchr("/._-", *name))
  				len++;
  		}
  
  		return len;
  	}
  
  	return t - target;
  }
  
  
  /*
   * aafs - core fns and data for the policy tree
   */
  
  #define AAFS_NAME		"apparmorfs"
  static struct vfsmount *aafs_mnt;
  static int aafs_count;
  
  
  static int aafs_show_path(struct seq_file *seq, struct dentry *dentry)
  {
  	seq_printf(seq, "%s:[%lu]", AAFS_NAME, d_inode(dentry)->i_ino);
  	return 0;
  }
  
  static void aafs_free_inode(struct inode *inode)
  {
  	if (S_ISLNK(inode->i_mode))
  		kfree(inode->i_link);
  	free_inode_nonrcu(inode);
  }
  
  static const struct super_operations aafs_super_ops = {
  	.statfs = simple_statfs,
  	.free_inode = aafs_free_inode,
  	.show_path = aafs_show_path,
  };
  
  static int fill_super(struct super_block *sb, void *data, int silent)
  {
  	static struct tree_descr files[] = { {""} };
  	int error;
  
  	error = simple_fill_super(sb, AAFS_MAGIC, files);
  	if (error)
  		return error;
  	sb->s_op = &aafs_super_ops;
  
  	return 0;
  }
  
  static struct dentry *aafs_mount(struct file_system_type *fs_type,
  				 int flags, const char *dev_name, void *data)
  {
  	return mount_single(fs_type, flags, data, fill_super);
  }
  
  static struct file_system_type aafs_ops = {
  	.owner = THIS_MODULE,
  	.name = AAFS_NAME,
  	.mount = aafs_mount,
  	.kill_sb = kill_anon_super,
  };
  
  /**
   * __aafs_setup_d_inode - basic inode setup for apparmorfs
   * @dir: parent directory for the dentry
   * @dentry: dentry we are seting the inode up for
   * @mode: permissions the file should have
   * @data: data to store on inode.i_private, available in open()
   * @link: if symlink, symlink target string
   * @fops: struct file_operations that should be used
   * @iops: struct of inode_operations that should be used
   */
  static int __aafs_setup_d_inode(struct inode *dir, struct dentry *dentry,
  			       umode_t mode, void *data, char *link,
  			       const struct file_operations *fops,
  			       const struct inode_operations *iops)
  {
  	struct inode *inode = new_inode(dir->i_sb);
  
  	AA_BUG(!dir);
  	AA_BUG(!dentry);
  
  	if (!inode)
  		return -ENOMEM;
  
  	inode->i_ino = get_next_ino();
  	inode->i_mode = mode;
  	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
  	inode->i_private = data;
  	if (S_ISDIR(mode)) {
  		inode->i_op = iops ? iops : &simple_dir_inode_operations;
  		inode->i_fop = &simple_dir_operations;
  		inc_nlink(inode);
  		inc_nlink(dir);
  	} else if (S_ISLNK(mode)) {
  		inode->i_op = iops ? iops : &simple_symlink_inode_operations;
  		inode->i_link = link;
  	} else {
  		inode->i_fop = fops;
  	}
  	d_instantiate(dentry, inode);
  	dget(dentry);
  
  	return 0;
  }
  
  /**
   * aafs_create - create a dentry in the apparmorfs filesystem
   *
   * @name: name of dentry to create
   * @mode: permissions the file should have
   * @parent: parent directory for this dentry
   * @data: data to store on inode.i_private, available in open()
   * @link: if symlink, symlink target string
   * @fops: struct file_operations that should be used for
   * @iops: struct of inode_operations that should be used
   *
   * This is the basic "create a xxx" function for apparmorfs.
   *
   * Returns a pointer to a dentry if it succeeds, that must be free with
   * aafs_remove(). Will return ERR_PTR on failure.
   */
  static struct dentry *aafs_create(const char *name, umode_t mode,
  				  struct dentry *parent, void *data, void *link,
  				  const struct file_operations *fops,
  				  const struct inode_operations *iops)
  {
  	struct dentry *dentry;
  	struct inode *dir;
  	int error;
  
  	AA_BUG(!name);
  	AA_BUG(!parent);
  
  	if (!(mode & S_IFMT))
  		mode = (mode & S_IALLUGO) | S_IFREG;
  
  	error = simple_pin_fs(&aafs_ops, &aafs_mnt, &aafs_count);
  	if (error)
  		return ERR_PTR(error);
  
  	dir = d_inode(parent);
  
  	inode_lock(dir);
  	dentry = lookup_one_len(name, parent, strlen(name));
  	if (IS_ERR(dentry)) {
  		error = PTR_ERR(dentry);
  		goto fail_lock;
  	}
  
  	if (d_really_is_positive(dentry)) {
  		error = -EEXIST;
  		goto fail_dentry;
  	}
  
  	error = __aafs_setup_d_inode(dir, dentry, mode, data, link, fops, iops);
  	if (error)
  		goto fail_dentry;
  	inode_unlock(dir);
  
  	return dentry;
  
  fail_dentry:
  	dput(dentry);
  
  fail_lock:
  	inode_unlock(dir);
  	simple_release_fs(&aafs_mnt, &aafs_count);
  
  	return ERR_PTR(error);
  }
  
  /**
   * aafs_create_file - create a file in the apparmorfs filesystem
   *
   * @name: name of dentry to create
   * @mode: permissions the file should have
   * @parent: parent directory for this dentry
   * @data: data to store on inode.i_private, available in open()
   * @fops: struct file_operations that should be used for
   *
   * see aafs_create
   */
  static struct dentry *aafs_create_file(const char *name, umode_t mode,
  				       struct dentry *parent, void *data,
  				       const struct file_operations *fops)
  {
  	return aafs_create(name, mode, parent, data, NULL, fops, NULL);
  }
  
  /**
   * aafs_create_dir - create a directory in the apparmorfs filesystem
   *
   * @name: name of dentry to create
   * @parent: parent directory for this dentry
   *
   * see aafs_create
   */
  static struct dentry *aafs_create_dir(const char *name, struct dentry *parent)
  {
  	return aafs_create(name, S_IFDIR | 0755, parent, NULL, NULL, NULL,
  			   NULL);
  }
  
  /**
   * aafs_create_symlink - create a symlink in the apparmorfs filesystem
   * @name: name of dentry to create
   * @parent: parent directory for this dentry
   * @target: if symlink, symlink target string
   * @private: private data
   * @iops: struct of inode_operations that should be used
   *
   * If @target parameter is %NULL, then the @iops parameter needs to be
   * setup to handle .readlink and .get_link inode_operations.
   */
  static struct dentry *aafs_create_symlink(const char *name,
  					  struct dentry *parent,
  					  const char *target,
  					  void *private,
  					  const struct inode_operations *iops)
  {
  	struct dentry *dent;
  	char *link = NULL;
  
  	if (target) {
  		if (!link)
  			return ERR_PTR(-ENOMEM);
  	}
  	dent = aafs_create(name, S_IFLNK | 0444, parent, private, link, NULL,
  			   iops);
  	if (IS_ERR(dent))
  		kfree(link);
  
  	return dent;
  }
  
  /**
   * aafs_remove - removes a file or directory from the apparmorfs filesystem
   *
   * @dentry: dentry of the file/directory/symlink to removed.
   */
  static void aafs_remove(struct dentry *dentry)
  {
  	struct inode *dir;
  
  	if (!dentry || IS_ERR(dentry))
  		return;
  
  	dir = d_inode(dentry->d_parent);
  	inode_lock(dir);
  	if (simple_positive(dentry)) {
  		if (d_is_dir(dentry))
  			simple_rmdir(dir, dentry);
  		else
  			simple_unlink(dir, dentry);
  		d_delete(dentry);
  		dput(dentry);
  	}
  	inode_unlock(dir);
  	simple_release_fs(&aafs_mnt, &aafs_count);
  }
  
  
  /*
   * aa_fs - policy load/replace/remove
   */
  
  /**
   * aa_simple_write_to_buffer - common routine for getting policy from user
   * @userbuf: user buffer to copy data from  (NOT NULL)
   * @alloc_size: size of user buffer (REQUIRES: @alloc_size >= @copy_size)
   * @copy_size: size of data to copy from user buffer
   * @pos: position write is at in the file (NOT NULL)
   *
   * Returns: kernel buffer containing copy of user buffer data or an
   *          ERR_PTR on failure.
   */
  static struct aa_loaddata *aa_simple_write_to_buffer(const char __user *userbuf,
  						     size_t alloc_size,
  						     size_t copy_size,
  						     loff_t *pos)
  {
  	struct aa_loaddata *data;
  
  	AA_BUG(copy_size > alloc_size);
  
  	if (*pos != 0)
  		/* only writes from pos 0, that is complete writes */
  		return ERR_PTR(-ESPIPE);
  
  	/* freed by caller to simple_write_to_buffer */
  	data = aa_loaddata_alloc(alloc_size);
  	if (IS_ERR(data))
  		return data;
  
  	data->size = copy_size;
  	if (copy_from_user(data->data, userbuf, copy_size)) {
  		kvfree(data);
  		return ERR_PTR(-EFAULT);
  	}
  
  	return data;
  }
  
  static ssize_t policy_update(u32 mask, const char __user *buf, size_t size,
  			     loff_t *pos, struct aa_ns *ns)
  {
  	struct aa_loaddata *data;
  	struct aa_label *label;
  	ssize_t error;
  
  	label = begin_current_label_crit_section();
  
  	/* high level check about policy management - fine grained in
  	 * below after unpack
  	 */
  	error = aa_may_manage_policy(label, ns, mask);
  	if (error)
  		return error;
  
  	data = aa_simple_write_to_buffer(buf, size, size, pos);
  	error = PTR_ERR(data);
  	if (!IS_ERR(data)) {
  		error = aa_replace_profiles(ns, label, mask, data);
  		aa_put_loaddata(data);
  	}
  	end_current_label_crit_section(label);
  
  	return error;
  }
  
  /* .load file hook fn to load policy */
  static ssize_t profile_load(struct file *f, const char __user *buf, size_t size,
  			    loff_t *pos)
  {
  	struct aa_ns *ns = aa_get_ns(f->f_inode->i_private);
  	int error = policy_update(AA_MAY_LOAD_POLICY, buf, size, pos, ns);
  
  	aa_put_ns(ns);
  
  	return error;
  }
  
  static const struct file_operations aa_fs_profile_load = {
  	.write = profile_load,
  	.llseek = default_llseek,
  };
  
  /* .replace file hook fn to load and/or replace policy */
  static ssize_t profile_replace(struct file *f, const char __user *buf,
  			       size_t size, loff_t *pos)
  {
  	struct aa_ns *ns = aa_get_ns(f->f_inode->i_private);
  	int error = policy_update(AA_MAY_LOAD_POLICY | AA_MAY_REPLACE_POLICY,
  				  buf, size, pos, ns);
  	aa_put_ns(ns);
  
  	return error;
  }
  
  static const struct file_operations aa_fs_profile_replace = {
  	.write = profile_replace,
  	.llseek = default_llseek,
  };
  
  /* .remove file hook fn to remove loaded policy */
  static ssize_t profile_remove(struct file *f, const char __user *buf,
  			      size_t size, loff_t *pos)
  {
  	struct aa_loaddata *data;
  	struct aa_label *label;
  	ssize_t error;
  	struct aa_ns *ns = aa_get_ns(f->f_inode->i_private);
  
  	label = begin_current_label_crit_section();
  	/* high level check about policy management - fine grained in
  	 * below after unpack
  	 */
  	error = aa_may_manage_policy(label, ns, AA_MAY_REMOVE_POLICY);
  	if (error)
  		goto out;
  
  	/*
  	 * aa_remove_profile needs a null terminated string so 1 extra
  	 * byte is allocated and the copied data is null terminated.
  	 */
  	data = aa_simple_write_to_buffer(buf, size + 1, size, pos);
  
  	error = PTR_ERR(data);
  	if (!IS_ERR(data)) {
  		data->data[size] = 0;
  		error = aa_remove_profiles(ns, label, data->data, size);
  		aa_put_loaddata(data);
  	}
   out:
  	end_current_label_crit_section(label);
  	aa_put_ns(ns);
  	return error;
  }
  
  static const struct file_operations aa_fs_profile_remove = {
  	.write = profile_remove,
  	.llseek = default_llseek,
  };
  
  struct aa_revision {
  	struct aa_ns *ns;
  	long last_read;
  };
  
  /* revision file hook fn for policy loads */
  static int ns_revision_release(struct inode *inode, struct file *file)
  {
  	struct aa_revision *rev = file->private_data;
  
  	if (rev) {
  		aa_put_ns(rev->ns);
  		kfree(rev);
  	}
  
  	return 0;
  }
  
  static ssize_t ns_revision_read(struct file *file, char __user *buf,
  				size_t size, loff_t *ppos)
  {
  	struct aa_revision *rev = file->private_data;
  	char buffer[32];
  	long last_read;
  	int avail;
  
  	mutex_lock_nested(&rev->ns->lock, rev->ns->level);
  	last_read = rev->last_read;
  	if (last_read == rev->ns->revision) {
  		mutex_unlock(&rev->ns->lock);
  		if (file->f_flags & O_NONBLOCK)
  			return -EAGAIN;
  		if (wait_event_interruptible(rev->ns->wait,
  					     last_read !=
  					     READ_ONCE(rev->ns->revision)))
  			return -ERESTARTSYS;
  		mutex_lock_nested(&rev->ns->lock, rev->ns->level);
  	}
  
  	avail = sprintf(buffer, "%ld\n", rev->ns->revision);
  	if (*ppos + size > avail) {
  		rev->last_read = rev->ns->revision;
  		*ppos = 0;
  	}
  	mutex_unlock(&rev->ns->lock);
  
  	return simple_read_from_buffer(buf, size, ppos, buffer, avail);
  }
  
  static int ns_revision_open(struct inode *inode, struct file *file)
  {
  	struct aa_revision *rev = kzalloc(sizeof(*rev), GFP_KERNEL);
  
  	if (!rev)
  		return -ENOMEM;
  
  	rev->ns = aa_get_ns(inode->i_private);
  	if (!rev->ns)
  		rev->ns = aa_get_current_ns();
  	file->private_data = rev;
  
  	return 0;
  }
  
  static __poll_t ns_revision_poll(struct file *file, poll_table *pt)
  {
  	struct aa_revision *rev = file->private_data;
  	__poll_t mask = 0;
  
  	if (rev) {
  		mutex_lock_nested(&rev->ns->lock, rev->ns->level);
  		poll_wait(file, &rev->ns->wait, pt);
  		if (rev->last_read < rev->ns->revision)
  			mask |= EPOLLIN | EPOLLRDNORM;
  		mutex_unlock(&rev->ns->lock);
  	}
  
  	return mask;
  }
  
  void __aa_bump_ns_revision(struct aa_ns *ns)
  {
  	ns->revision++;
  	wake_up_interruptible(&ns->wait);
  }
  
  static const struct file_operations aa_fs_ns_revision_fops = {
  	.owner		= THIS_MODULE,
  	.open		= ns_revision_open,
  	.poll		= ns_revision_poll,
  	.read		= ns_revision_read,
  	.llseek		= generic_file_llseek,
  	.release	= ns_revision_release,
  };
  
  static void profile_query_cb(struct aa_profile *profile, struct aa_perms *perms,
  			     const char *match_str, size_t match_len)
  {
  	struct aa_perms tmp = { };
  	struct aa_dfa *dfa;
  	unsigned int state = 0;
  
  	if (profile_unconfined(profile))
  		return;
  	if (profile->file.dfa && *match_str == AA_CLASS_FILE) {
  		dfa = profile->file.dfa;
  		state = aa_dfa_match_len(dfa, profile->file.start,
  					 match_str + 1, match_len - 1);
  		if (state) {
  			struct path_cond cond = { };
  
  			tmp = aa_compute_fperms(dfa, state, &cond);
  		}
  	} else if (profile->policy.dfa) {
  		if (!PROFILE_MEDIATES(profile, *match_str))
  			return;	/* no change to current perms */
  		dfa = profile->policy.dfa;
  		state = aa_dfa_match_len(dfa, profile->policy.start[0],
  					 match_str, match_len);
  		if (state)
  			aa_compute_perms(dfa, state, &tmp);
  	}
  	aa_apply_modes_to_perms(profile, &tmp);
  	aa_perms_accum_raw(perms, &tmp);
  }
  
  
  /**
   * query_data - queries a policy and writes its data to buf
   * @buf: the resulting data is stored here (NOT NULL)
   * @buf_len: size of buf
   * @query: query string used to retrieve data
   * @query_len: size of query including second NUL byte
   *
   * The buffers pointed to by buf and query may overlap. The query buffer is
   * parsed before buf is written to.
   *
   * The query should look like "<LABEL>\0<KEY>\0", where <LABEL> is the name of
   * the security confinement context and <KEY> is the name of the data to
   * retrieve. <LABEL> and <KEY> must not be NUL-terminated.
   *
   * Don't expect the contents of buf to be preserved on failure.
   *
   * Returns: number of characters written to buf or -errno on failure
   */
  static ssize_t query_data(char *buf, size_t buf_len,
  			  char *query, size_t query_len)
  {
  	char *out;
  	const char *key;
  	struct label_it i;
  	struct aa_label *label, *curr;
  	struct aa_profile *profile;
  	struct aa_data *data;
  	u32 bytes, blocks;
  	__le32 outle32;
  
  	if (!query_len)
  		return -EINVAL; /* need a query */
  
  	key = query + strnlen(query, query_len) + 1;
  	if (key + 1 >= query + query_len)
  		return -EINVAL; /* not enough space for a non-empty key */
  	if (key + strnlen(key, query + query_len - key) >= query + query_len)
  		return -EINVAL; /* must end with NUL */
  
  	if (buf_len < sizeof(bytes) + sizeof(blocks))
  		return -EINVAL; /* not enough space */
  
  	curr = begin_current_label_crit_section();
  	label = aa_label_parse(curr, query, GFP_KERNEL, false, false);
  	end_current_label_crit_section(curr);
  	if (IS_ERR(label))
  		return PTR_ERR(label);
  
  	/* We are going to leave space for two numbers. The first is the total
  	 * number of bytes we are writing after the first number. This is so
  	 * users can read the full output without reallocation.
  	 *
  	 * The second number is the number of data blocks we're writing. An
  	 * application might be confined by multiple policies having data in
  	 * the same key.
  	 */
  	memset(buf, 0, sizeof(bytes) + sizeof(blocks));
  	out = buf + sizeof(bytes) + sizeof(blocks);
  
  	blocks = 0;
  	label_for_each_confined(i, label, profile) {
  		if (!profile->data)
  			continue;
  
  		data = rhashtable_lookup_fast(profile->data, &key,
  					      profile->data->p);
  
  		if (data) {
  			if (out + sizeof(outle32) + data->size > buf +
  			    buf_len) {
  				aa_put_label(label);
  				return -EINVAL; /* not enough space */
  			}
  			outle32 = __cpu_to_le32(data->size);
  			memcpy(out, &outle32, sizeof(outle32));
  			out += sizeof(outle32);
  			memcpy(out, data->data, data->size);
  			out += data->size;
  			blocks++;
  		}
  	}
  	aa_put_label(label);
  
  	outle32 = __cpu_to_le32(out - buf - sizeof(bytes));
  	memcpy(buf, &outle32, sizeof(outle32));
  	outle32 = __cpu_to_le32(blocks);
  	memcpy(buf + sizeof(bytes), &outle32, sizeof(outle32));
  
  	return out - buf;
  }
  
  /**
   * query_label - queries a label and writes permissions to buf
   * @buf: the resulting permissions string is stored here (NOT NULL)
   * @buf_len: size of buf
   * @query: binary query string to match against the dfa
   * @query_len: size of query
   * @view_only: only compute for querier's view
   *
   * The buffers pointed to by buf and query may overlap. The query buffer is
   * parsed before buf is written to.
   *
   * The query should look like "LABEL_NAME\0DFA_STRING" where LABEL_NAME is
   * the name of the label, in the current namespace, that is to be queried and
   * DFA_STRING is a binary string to match against the label(s)'s DFA.
   *
   * LABEL_NAME must be NUL terminated. DFA_STRING may contain NUL characters
   * but must *not* be NUL terminated.
   *
   * Returns: number of characters written to buf or -errno on failure
   */
  static ssize_t query_label(char *buf, size_t buf_len,
  			   char *query, size_t query_len, bool view_only)
  {
  	struct aa_profile *profile;
  	struct aa_label *label, *curr;
  	char *label_name, *match_str;
  	size_t label_name_len, match_len;
  	struct aa_perms perms;
  	struct label_it i;
  
  	if (!query_len)
  		return -EINVAL;
  
  	label_name = query;
  	label_name_len = strnlen(query, query_len);
  	if (!label_name_len || label_name_len == query_len)
  		return -EINVAL;
  
  	/**
  	 * The extra byte is to account for the null byte between the
  	 * profile name and dfa string. profile_name_len is greater
  	 * than zero and less than query_len, so a byte can be safely
  	 * added or subtracted.
  	 */
  	match_str = label_name + label_name_len + 1;
  	match_len = query_len - label_name_len - 1;
  
  	curr = begin_current_label_crit_section();
  	label = aa_label_parse(curr, label_name, GFP_KERNEL, false, false);
  	end_current_label_crit_section(curr);
  	if (IS_ERR(label))
  		return PTR_ERR(label);
  
  	perms = allperms;
  	if (view_only) {
  		label_for_each_in_ns(i, labels_ns(label), label, profile) {
  			profile_query_cb(profile, &perms, match_str, match_len);
  		}
  	} else {
  		label_for_each(i, label, profile) {
  			profile_query_cb(profile, &perms, match_str, match_len);
  		}
  	}
  	aa_put_label(label);
  
  	return scnprintf(buf, buf_len,
  		      "allow 0x%08x\ndeny 0x%08x\naudit 0x%08x\nquiet 0x%08x\n",
  		      perms.allow, perms.deny, perms.audit, perms.quiet);
  }
  
  /*
   * Transaction based IO.
   * The file expects a write which triggers the transaction, and then
   * possibly a read(s) which collects the result - which is stored in a
   * file-local buffer. Once a new write is performed, a new set of results
   * are stored in the file-local buffer.
   */
  struct multi_transaction {
  	struct kref count;
  	ssize_t size;
  	char data[0];
  };
  
  #define MULTI_TRANSACTION_LIMIT (PAGE_SIZE - sizeof(struct multi_transaction))
  /* TODO: replace with per file lock */
  static DEFINE_SPINLOCK(multi_transaction_lock);
  
  static void multi_transaction_kref(struct kref *kref)
  {
  	struct multi_transaction *t;
  
  	t = container_of(kref, struct multi_transaction, count);
  	free_page((unsigned long) t);
  }
  
  static struct multi_transaction *
  get_multi_transaction(struct multi_transaction *t)
  {
  	if  (t)
  		kref_get(&(t->count));
  
  	return t;
  }
  
  static void put_multi_transaction(struct multi_transaction *t)
  {
  	if (t)
  		kref_put(&(t->count), multi_transaction_kref);
  }
  
  /* does not increment @new's count */
  static void multi_transaction_set(struct file *file,
  				  struct multi_transaction *new, size_t n)
  {
  	struct multi_transaction *old;
  
  	AA_BUG(n > MULTI_TRANSACTION_LIMIT);
  
  	new->size = n;
  	spin_lock(&multi_transaction_lock);
  	old = (struct multi_transaction *) file->private_data;
  	file->private_data = new;
  	spin_unlock(&multi_transaction_lock);
  	put_multi_transaction(old);
  }
  
  static struct multi_transaction *multi_transaction_new(struct file *file,
  						       const char __user *buf,
  						       size_t size)
  {
  	struct multi_transaction *t;
  
  	if (size > MULTI_TRANSACTION_LIMIT - 1)
  		return ERR_PTR(-EFBIG);
  
  	t = (struct multi_transaction *)get_zeroed_page(GFP_KERNEL);
  	if (!t)
  		return ERR_PTR(-ENOMEM);
  	kref_init(&t->count);
  	if (copy_from_user(t->data, buf, size))
  		return ERR_PTR(-EFAULT);
  
  	return t;
  }
  
  static ssize_t multi_transaction_read(struct file *file, char __user *buf,
  				       size_t size, loff_t *pos)
  {
  	struct multi_transaction *t;
  	ssize_t ret;
  
  	spin_lock(&multi_transaction_lock);
  	t = get_multi_transaction(file->private_data);
  	spin_unlock(&multi_transaction_lock);
  	if (!t)
  		return 0;
  
  	ret = simple_read_from_buffer(buf, size, pos, t->data, t->size);
  	put_multi_transaction(t);
  
  	return ret;
  }
  
  static int multi_transaction_release(struct inode *inode, struct file *file)
  {
  	put_multi_transaction(file->private_data);
  
  	return 0;
  }
  
  #define QUERY_CMD_LABEL		"label\0"
  #define QUERY_CMD_LABEL_LEN	6
  #define QUERY_CMD_PROFILE	"profile\0"
  #define QUERY_CMD_PROFILE_LEN	8
  #define QUERY_CMD_LABELALL	"labelall\0"
  #define QUERY_CMD_LABELALL_LEN	9
  #define QUERY_CMD_DATA		"data\0"
  #define QUERY_CMD_DATA_LEN	5
  
  /**
   * aa_write_access - generic permissions and data query
   * @file: pointer to open apparmorfs/access file
   * @ubuf: user buffer containing the complete query string (NOT NULL)
   * @count: size of ubuf
   * @ppos: position in the file (MUST BE ZERO)
   *
   * Allows for one permissions or data query per open(), write(), and read()
   * sequence. The only queries currently supported are label-based queries for
   * permissions or data.
   *
   * For permissions queries, ubuf must begin with "label\0", followed by the
   * profile query specific format described in the query_label() function
   * documentation.
   *
   * For data queries, ubuf must have the form "data\0<LABEL>\0<KEY>\0", where
   * <LABEL> is the name of the security confinement context and <KEY> is the
   * name of the data to retrieve.
   *
   * Returns: number of bytes written or -errno on failure
   */
  static ssize_t aa_write_access(struct file *file, const char __user *ubuf,
  			       size_t count, loff_t *ppos)
  {
  	struct multi_transaction *t;
  	ssize_t len;
  
  	if (*ppos)
  		return -ESPIPE;
  
  	t = multi_transaction_new(file, ubuf, count);
  	if (IS_ERR(t))
  		return PTR_ERR(t);
  
  	if (count > QUERY_CMD_PROFILE_LEN &&
  	    !memcmp(t->data, QUERY_CMD_PROFILE, QUERY_CMD_PROFILE_LEN)) {
  		len = query_label(t->data, MULTI_TRANSACTION_LIMIT,
  				  t->data + QUERY_CMD_PROFILE_LEN,
  				  count - QUERY_CMD_PROFILE_LEN, true);
  	} else if (count > QUERY_CMD_LABEL_LEN &&
  		   !memcmp(t->data, QUERY_CMD_LABEL, QUERY_CMD_LABEL_LEN)) {
  		len = query_label(t->data, MULTI_TRANSACTION_LIMIT,
  				  t->data + QUERY_CMD_LABEL_LEN,
  				  count - QUERY_CMD_LABEL_LEN, true);
  	} else if (count > QUERY_CMD_LABELALL_LEN &&
  		   !memcmp(t->data, QUERY_CMD_LABELALL,
  			   QUERY_CMD_LABELALL_LEN)) {
  		len = query_label(t->data, MULTI_TRANSACTION_LIMIT,
  				  t->data + QUERY_CMD_LABELALL_LEN,
  				  count - QUERY_CMD_LABELALL_LEN, false);
  	} else if (count > QUERY_CMD_DATA_LEN &&
  		   !memcmp(t->data, QUERY_CMD_DATA, QUERY_CMD_DATA_LEN)) {
  		len = query_data(t->data, MULTI_TRANSACTION_LIMIT,
  				 t->data + QUERY_CMD_DATA_LEN,
  				 count - QUERY_CMD_DATA_LEN);
  	} else
  		len = -EINVAL;
  
  	if (len < 0) {
  		put_multi_transaction(t);
  		return len;
  	}
  
  	multi_transaction_set(file, t, len);
  
  	return count;
  }
  
  static const struct file_operations aa_sfs_access = {
  	.write		= aa_write_access,
  	.read		= multi_transaction_read,
  	.release	= multi_transaction_release,
  	.llseek		= generic_file_llseek,
  };
  
  static int aa_sfs_seq_show(struct seq_file *seq, void *v)
  {
  	struct aa_sfs_entry *fs_file = seq->private;
  
  	if (!fs_file)
  		return 0;
  
  	switch (fs_file->v_type) {
  	case AA_SFS_TYPE_BOOLEAN:
  		seq_printf(seq, "%s\n", fs_file->v.boolean ? "yes" : "no");
  		break;
  	case AA_SFS_TYPE_STRING:
  		seq_printf(seq, "%s\n", fs_file->v.string);
  		break;
  	case AA_SFS_TYPE_U64:
  		seq_printf(seq, "%#08lx\n", fs_file->v.u64);
  		break;
  	default:
  		/* Ignore unpritable entry types. */
  		break;
  	}
  
  	return 0;
  }
  
  static int aa_sfs_seq_open(struct inode *inode, struct file *file)
  {
  	return single_open(file, aa_sfs_seq_show, inode->i_private);
  }
  
  const struct file_operations aa_sfs_seq_file_ops = {
  	.owner		= THIS_MODULE,
  	.open		= aa_sfs_seq_open,
  	.read		= seq_read,
  	.llseek		= seq_lseek,
  	.release	= single_release,
  };
  
  /*
   * profile based file operations
   *     policy/profiles/XXXX/profiles/ *
   */
  
  #define SEQ_PROFILE_FOPS(NAME)						      \
  static int seq_profile_ ##NAME ##_open(struct inode *inode, struct file *file)\
  {									      \
  	return seq_profile_open(inode, file, seq_profile_ ##NAME ##_show);    \
  }									      \
  									      \
  static const struct file_operations seq_profile_ ##NAME ##_fops = {	      \
  	.owner		= THIS_MODULE,					      \
  	.open		= seq_profile_ ##NAME ##_open,			      \
  	.read		= seq_read,					      \
  	.llseek		= seq_lseek,					      \
  	.release	= seq_profile_release,				      \
  }									      \
  
  static int seq_profile_open(struct inode *inode, struct file *file,
  			    int (*show)(struct seq_file *, void *))
  {
  	struct aa_proxy *proxy = aa_get_proxy(inode->i_private);
  	int error = single_open(file, show, proxy);
  
  	if (error) {
  		file->private_data = NULL;
  		aa_put_proxy(proxy);
  	}
  
  	return error;
  }
  
  static int seq_profile_release(struct inode *inode, struct file *file)
  {
  	struct seq_file *seq = (struct seq_file *) file->private_data;
  	if (seq)
  		aa_put_proxy(seq->private);
  	return single_release(inode, file);
  }
  
  static int seq_profile_name_show(struct seq_file *seq, void *v)
  {
  	struct aa_proxy *proxy = seq->private;
  	struct aa_label *label = aa_get_label_rcu(&proxy->label);
  	struct aa_profile *profile = labels_profile(label);
  	seq_printf(seq, "%s\n", profile->base.name);
  	aa_put_label(label);
  
  	return 0;
  }
  
  static int seq_profile_mode_show(struct seq_file *seq, void *v)
  {
  	struct aa_proxy *proxy = seq->private;
  	struct aa_label *label = aa_get_label_rcu(&proxy->label);
  	struct aa_profile *profile = labels_profile(label);
  	seq_printf(seq, "%s\n", aa_profile_mode_names[profile->mode]);
  	aa_put_label(label);
  
  	return 0;
  }
  
  static int seq_profile_attach_show(struct seq_file *seq, void *v)
  {
  	struct aa_proxy *proxy = seq->private;
  	struct aa_label *label = aa_get_label_rcu(&proxy->label);
  	struct aa_profile *profile = labels_profile(label);
  	if (profile->attach)
  		seq_printf(seq, "%s\n", profile->attach);
  	else if (profile->xmatch)
  		seq_puts(seq, "<unknown>\n");
  	else
  		seq_printf(seq, "%s\n", profile->base.name);
  	aa_put_label(label);
  
  	return 0;
  }
  
  static int seq_profile_hash_show(struct seq_file *seq, void *v)
  {
  	struct aa_proxy *proxy = seq->private;
  	struct aa_label *label = aa_get_label_rcu(&proxy->label);
  	struct aa_profile *profile = labels_profile(label);
  	unsigned int i, size = aa_hash_size();
  
  	if (profile->hash) {
  		for (i = 0; i < size; i++)
  			seq_printf(seq, "%.2x", profile->hash[i]);
  		seq_putc(seq, '\n');
  	}
  	aa_put_label(label);
  
  	return 0;
  }
  
  SEQ_PROFILE_FOPS(name);
  SEQ_PROFILE_FOPS(mode);
  SEQ_PROFILE_FOPS(attach);
  SEQ_PROFILE_FOPS(hash);
  
  /*
   * namespace based files
   *     several root files and
   *     policy/ *
   */
  
  #define SEQ_NS_FOPS(NAME)						      \
  static int seq_ns_ ##NAME ##_open(struct inode *inode, struct file *file)     \
  {									      \
  	return single_open(file, seq_ns_ ##NAME ##_show, inode->i_private);   \
  }									      \
  									      \
  static const struct file_operations seq_ns_ ##NAME ##_fops = {	      \
  	.owner		= THIS_MODULE,					      \
  	.open		= seq_ns_ ##NAME ##_open,			      \
  	.read		= seq_read,					      \
  	.llseek		= seq_lseek,					      \
  	.release	= single_release,				      \
  }									      \
  
  static int seq_ns_stacked_show(struct seq_file *seq, void *v)
  {
  	struct aa_label *label;
  
  	label = begin_current_label_crit_section();
  	seq_printf(seq, "%s\n", label->size > 1 ? "yes" : "no");
  	end_current_label_crit_section(label);
  
  	return 0;
  }
  
  static int seq_ns_nsstacked_show(struct seq_file *seq, void *v)
  {
  	struct aa_label *label;
  	struct aa_profile *profile;
  	struct label_it it;
  	int count = 1;
  
  	label = begin_current_label_crit_section();
  
  	if (label->size > 1) {
  		label_for_each(it, label, profile)
  			if (profile->ns != labels_ns(label)) {
  				count++;
  				break;
  			}
  	}
  
  	seq_printf(seq, "%s\n", count > 1 ? "yes" : "no");
  	end_current_label_crit_section(label);
  
  	return 0;
  }
  
  static int seq_ns_level_show(struct seq_file *seq, void *v)
  {
  	struct aa_label *label;
  
  	label = begin_current_label_crit_section();
  	seq_printf(seq, "%d\n", labels_ns(label)->level);
  	end_current_label_crit_section(label);
  
  	return 0;
  }
  
  static int seq_ns_name_show(struct seq_file *seq, void *v)
  {
  	struct aa_label *label = begin_current_label_crit_section();
  	seq_printf(seq, "%s\n", labels_ns(label)->base.name);
  	end_current_label_crit_section(label);
  
  	return 0;
  }
  
  SEQ_NS_FOPS(stacked);
  SEQ_NS_FOPS(nsstacked);
  SEQ_NS_FOPS(level);
  SEQ_NS_FOPS(name);
  
  
  /* policy/raw_data/ * file ops */
  
  #define SEQ_RAWDATA_FOPS(NAME)						      \
  static int seq_rawdata_ ##NAME ##_open(struct inode *inode, struct file *file)\
  {									      \
  	return seq_rawdata_open(inode, file, seq_rawdata_ ##NAME ##_show);    \
  }									      \
  									      \
  static const struct file_operations seq_rawdata_ ##NAME ##_fops = {	      \
  	.owner		= THIS_MODULE,					      \
  	.open		= seq_rawdata_ ##NAME ##_open,			      \
  	.read		= seq_read,					      \
  	.llseek		= seq_lseek,					      \
  	.release	= seq_rawdata_release,				      \
  }									      \
  
  static int seq_rawdata_open(struct inode *inode, struct file *file,
  			    int (*show)(struct seq_file *, void *))
  {
  	struct aa_loaddata *data = __aa_get_loaddata(inode->i_private);
  	int error;
  
  	if (!data)
  		/* lost race this ent is being reaped */
  		return -ENOENT;
  
  	error = single_open(file, show, data);
  	if (error) {
  		AA_BUG(file->private_data &&
  		       ((struct seq_file *)file->private_data)->private);
  		aa_put_loaddata(data);
  	}
  
  	return error;
  }
  
  static int seq_rawdata_release(struct inode *inode, struct file *file)
  {
  	struct seq_file *seq = (struct seq_file *) file->private_data;
  
  	if (seq)
  		aa_put_loaddata(seq->private);
  
  	return single_release(inode, file);
  }
  
  static int seq_rawdata_abi_show(struct seq_file *seq, void *v)
  {
  	struct aa_loaddata *data = seq->private;
  
  	seq_printf(seq, "v%d\n", data->abi);
  
  	return 0;
  }
  
  static int seq_rawdata_revision_show(struct seq_file *seq, void *v)
  {
  	struct aa_loaddata *data = seq->private;
  
  	seq_printf(seq, "%ld\n", data->revision);
  
  	return 0;
  }
  
  static int seq_rawdata_hash_show(struct seq_file *seq, void *v)
  {
  	struct aa_loaddata *data = seq->private;
  	unsigned int i, size = aa_hash_size();
  
  	if (data->hash) {
  		for (i = 0; i < size; i++)
  			seq_printf(seq, "%.2x", data->hash[i]);
  		seq_putc(seq, '\n');
  	}
  
  	return 0;
  }
  
  SEQ_RAWDATA_FOPS(abi);
  SEQ_RAWDATA_FOPS(revision);
  SEQ_RAWDATA_FOPS(hash);
  
  static ssize_t rawdata_read(struct file *file, char __user *buf, size_t size,
  			    loff_t *ppos)
  {
  	struct aa_loaddata *rawdata = file->private_data;
  
  	return simple_read_from_buffer(buf, size, ppos, rawdata->data,
  				       rawdata->size);
  }
  
  static int rawdata_release(struct inode *inode, struct file *file)
  {
  	aa_put_loaddata(file->private_data);
  
  	return 0;
  }
  
  static int rawdata_open(struct inode *inode, struct file *file)
  {
  	if (!policy_view_capable(NULL))
  		return -EACCES;
  	file->private_data = __aa_get_loaddata(inode->i_private);
  	if (!file->private_data)
  		/* lost race: this entry is being reaped */
  		return -ENOENT;
  
  	return 0;
  }
  
  static const struct file_operations rawdata_fops = {
  	.open = rawdata_open,
  	.read = rawdata_read,
  	.llseek = generic_file_llseek,
  	.release = rawdata_release,
  };
  
  static void remove_rawdata_dents(struct aa_loaddata *rawdata)
  {
  	int i;
  
  	for (i = 0; i < AAFS_LOADDATA_NDENTS; i++) {
  		if (!IS_ERR_OR_NULL(rawdata->dents[i])) {
  			/* no refcounts on i_private */
  			aafs_remove(rawdata->dents[i]);
  			rawdata->dents[i] = NULL;
  		}
  	}
  }
  
  void __aa_fs_remove_rawdata(struct aa_loaddata *rawdata)
  {
  	AA_BUG(rawdata->ns && !mutex_is_locked(&rawdata->ns->lock));
  
  	if (rawdata->ns) {
  		remove_rawdata_dents(rawdata);
  		list_del_init(&rawdata->list);
  		aa_put_ns(rawdata->ns);
  		rawdata->ns = NULL;
  	}
  }
  
  int __aa_fs_create_rawdata(struct aa_ns *ns, struct aa_loaddata *rawdata)
  {
  	struct dentry *dent, *dir;
  
  	AA_BUG(!ns);
  	AA_BUG(!rawdata);
  	AA_BUG(!mutex_is_locked(&ns->lock));
  	AA_BUG(!ns_subdata_dir(ns));
  
  	/*
  	 * just use ns revision dir was originally created at. This is
  	 * under ns->lock and if load is successful revision will be
  	 * bumped and is guaranteed to be unique
  	 */
  	rawdata->name = kasprintf(GFP_KERNEL, "%ld", ns->revision);
  	if (!rawdata->name)
  		return -ENOMEM;
  
  	dir = aafs_create_dir(rawdata->name, ns_subdata_dir(ns));
  	if (IS_ERR(dir))
  		/* ->name freed when rawdata freed */
  		return PTR_ERR(dir);
  	rawdata->dents[AAFS_LOADDATA_DIR] = dir;
  
  	dent = aafs_create_file("abi", S_IFREG | 0444, dir, rawdata,
  				      &seq_rawdata_abi_fops);
  	if (IS_ERR(dent))
  		goto fail;
  	rawdata->dents[AAFS_LOADDATA_ABI] = dent;
  
  	dent = aafs_create_file("revision", S_IFREG | 0444, dir, rawdata,
  				      &seq_rawdata_revision_fops);
  	if (IS_ERR(dent))
  		goto fail;
  	rawdata->dents[AAFS_LOADDATA_REVISION] = dent;
  
  	if (aa_g_hash_policy) {
  		dent = aafs_create_file("sha1", S_IFREG | 0444, dir,
  					      rawdata, &seq_rawdata_hash_fops);
  		if (IS_ERR(dent))
  			goto fail;
  		rawdata->dents[AAFS_LOADDATA_HASH] = dent;
  	}
  
  	dent = aafs_create_file("raw_data", S_IFREG | 0444,
  				      dir, rawdata, &rawdata_fops);
  	if (IS_ERR(dent))
  		goto fail;
  	rawdata->dents[AAFS_LOADDATA_DATA] = dent;
  	d_inode(dent)->i_size = rawdata->size;
  
  	rawdata->ns = aa_get_ns(ns);
  	list_add(&rawdata->list, &ns->rawdata_list);
  	/* no refcount on inode rawdata */
  
  	return 0;
  
  fail:
  	remove_rawdata_dents(rawdata);
  
  	return PTR_ERR(dent);
  }
  
  /** fns to setup dynamic per profile/namespace files **/
  
  /**
   *
   * Requires: @profile->ns->lock held
   */
  void __aafs_profile_rmdir(struct aa_profile *profile)
  {
  	struct aa_profile *child;
  	int i;
  
  	if (!profile)
  		return;
  
  	list_for_each_entry(child, &profile->base.profiles, base.list)
  		__aafs_profile_rmdir(child);
  
  	for (i = AAFS_PROF_SIZEOF - 1; i >= 0; --i) {
  		struct aa_proxy *proxy;
  		if (!profile->dents[i])
  			continue;
  
  		proxy = d_inode(profile->dents[i])->i_private;
  		aafs_remove(profile->dents[i]);
  		aa_put_proxy(proxy);
  		profile->dents[i] = NULL;
  	}
  }
  
  /**
   *
   * Requires: @old->ns->lock held
   */
  void __aafs_profile_migrate_dents(struct aa_profile *old,
  				  struct aa_profile *new)
  {
  	int i;
  
  	AA_BUG(!old);
  	AA_BUG(!new);
  	AA_BUG(!mutex_is_locked(&profiles_ns(old)->lock));
  
  	for (i = 0; i < AAFS_PROF_SIZEOF; i++) {
  		new->dents[i] = old->dents[i];
  		if (new->dents[i])
  			new->dents[i]->d_inode->i_mtime = current_time(new->dents[i]->d_inode);
  		old->dents[i] = NULL;
  	}
  }
  
  static struct dentry *create_profile_file(struct dentry *dir, const char *name,
  					  struct aa_profile *profile,
  					  const struct file_operations *fops)
  {
  	struct aa_proxy *proxy = aa_get_proxy(profile->label.proxy);
  	struct dentry *dent;
  
  	dent = aafs_create_file(name, S_IFREG | 0444, dir, proxy, fops);
  	if (IS_ERR(dent))
  		aa_put_proxy(proxy);
  
  	return dent;
  }
  
  static int profile_depth(struct aa_profile *profile)
  {
  	int depth = 0;
  
  	rcu_read_lock();
  	for (depth = 0; profile; profile = rcu_access_pointer(profile->parent))
  		depth++;
  	rcu_read_unlock();
  
  	return depth;
  }
  
  static char *gen_symlink_name(int depth, const char *dirname, const char *fname)
  {
  	char *buffer, *s;
  	int error;
  	int size = depth * 6 + strlen(dirname) + strlen(fname) + 11;
  
  	s = buffer = kmalloc(size, GFP_KERNEL);
  	if (!buffer)
  		return ERR_PTR(-ENOMEM);
  
  	for (; depth > 0; depth--) {
  		strcpy(s, "../../");
  		s += 6;
  		size -= 6;
  	}
  
  	error = snprintf(s, size, "raw_data/%s/%s", dirname, fname);
  	if (error >= size || error < 0) {
  		kfree(buffer);
  		return ERR_PTR(-ENAMETOOLONG);
  	}
  
  	return buffer;
  }
  
  static void rawdata_link_cb(void *arg)
  {
  	kfree(arg);
  }
  
  static const char *rawdata_get_link_base(struct dentry *dentry,
  					 struct inode *inode,
  					 struct delayed_call *done,
  					 const char *name)
  {
  	struct aa_proxy *proxy = inode->i_private;
  	struct aa_label *label;
  	struct aa_profile *profile;
  	char *target;
  	int depth;
  
  	if (!dentry)
  		return ERR_PTR(-ECHILD);
  
  	label = aa_get_label_rcu(&proxy->label);
  	profile = labels_profile(label);
  	depth = profile_depth(profile);
  	target = gen_symlink_name(depth, profile->rawdata->name, name);
  	aa_put_label(label);
  
  	if (IS_ERR(target))
  		return target;
  
  	set_delayed_call(done, rawdata_link_cb, target);
  
  	return target;
  }
  
  static const char *rawdata_get_link_sha1(struct dentry *dentry,
  					 struct inode *inode,
  					 struct delayed_call *done)
  {
  	return rawdata_get_link_base(dentry, inode, done, "sha1");
  }
  
  static const char *rawdata_get_link_abi(struct dentry *dentry,
  					struct inode *inode,
  					struct delayed_call *done)
  {
  	return rawdata_get_link_base(dentry, inode, done, "abi");
  }
  
  static const char *rawdata_get_link_data(struct dentry *dentry,
  					 struct inode *inode,
  					 struct delayed_call *done)
  {
  	return rawdata_get_link_base(dentry, inode, done, "raw_data");
  }
  
  static const struct inode_operations rawdata_link_sha1_iops = {
  	.get_link	= rawdata_get_link_sha1,
  };
  
  static const struct inode_operations rawdata_link_abi_iops = {
  	.get_link	= rawdata_get_link_abi,
  };
  static const struct inode_operations rawdata_link_data_iops = {
  	.get_link	= rawdata_get_link_data,
  };
  
  
  /*
   * Requires: @profile->ns->lock held
   */
  int __aafs_profile_mkdir(struct aa_profile *profile, struct dentry *parent)
  {
  	struct aa_profile *child;
  	struct dentry *dent = NULL, *dir;
  	int error;
  
  	AA_BUG(!profile);
  	AA_BUG(!mutex_is_locked(&profiles_ns(profile)->lock));
  
  	if (!parent) {
  		struct aa_profile *p;
  		p = aa_deref_parent(profile);
  		dent = prof_dir(p);
  		/* adding to parent that previously didn't have children */
  		dent = aafs_create_dir("profiles", dent);
  		if (IS_ERR(dent))
  			goto fail;
  		prof_child_dir(p) = parent = dent;
  	}
  
  	if (!profile->dirname) {
  		int len, id_len;
  		len = mangle_name(profile->base.name, NULL);
  		id_len = snprintf(NULL, 0, ".%ld", profile->ns->uniq_id);
  
  		profile->dirname = kmalloc(len + id_len + 1, GFP_KERNEL);
  		if (!profile->dirname) {
  			error = -ENOMEM;
  			goto fail2;
  		}
  
  		mangle_name(profile->base.name, profile->dirname);
  		sprintf(profile->dirname + len, ".%ld", profile->ns->uniq_id++);
  	}
  
  	dent = aafs_create_dir(profile->dirname, parent);
  	if (IS_ERR(dent))
  		goto fail;
  	prof_dir(profile) = dir = dent;
  
  	dent = create_profile_file(dir, "name", profile,
  				   &seq_profile_name_fops);
  	if (IS_ERR(dent))
  		goto fail;
  	profile->dents[AAFS_PROF_NAME] = dent;
  
  	dent = create_profile_file(dir, "mode", profile,
  				   &seq_profile_mode_fops);
  	if (IS_ERR(dent))
  		goto fail;
  	profile->dents[AAFS_PROF_MODE] = dent;
  
  	dent = create_profile_file(dir, "attach", profile,
  				   &seq_profile_attach_fops);
  	if (IS_ERR(dent))
  		goto fail;
  	profile->dents[AAFS_PROF_ATTACH] = dent;
  
  	if (profile->hash) {
  		dent = create_profile_file(dir, "sha1", profile,
  					   &seq_profile_hash_fops);
  		if (IS_ERR(dent))
  			goto fail;
  		profile->dents[AAFS_PROF_HASH] = dent;
  	}
  
  	if (profile->rawdata) {
  		dent = aafs_create_symlink("raw_sha1", dir, NULL,
  					   profile->label.proxy,
  					   &rawdata_link_sha1_iops);
  		if (IS_ERR(dent))
  			goto fail;
  		aa_get_proxy(profile->label.proxy);
  		profile->dents[AAFS_PROF_RAW_HASH] = dent;
  
  		dent = aafs_create_symlink("raw_abi", dir, NULL,
  					   profile->label.proxy,
  					   &rawdata_link_abi_iops);
  		if (IS_ERR(dent))
  			goto fail;
  		aa_get_proxy(profile->label.proxy);
  		profile->dents[AAFS_PROF_RAW_ABI] = dent;
  
  		dent = aafs_create_symlink("raw_data", dir, NULL,
  					   profile->label.proxy,
  					   &rawdata_link_data_iops);
  		if (IS_ERR(dent))
  			goto fail;
  		aa_get_proxy(profile->label.proxy);
  		profile->dents[AAFS_PROF_RAW_DATA] = dent;
  	}
  
  	list_for_each_entry(child, &profile->base.profiles, base.list) {
  		error = __aafs_profile_mkdir(child, prof_child_dir(profile));
  		if (error)
  			goto fail2;
  	}
  
  	return 0;
  
  fail:
  	error = PTR_ERR(dent);
  
  fail2:
  	__aafs_profile_rmdir(profile);
  
  	return error;
  }
  
  static int ns_mkdir_op(struct inode *dir, struct dentry *dentry, umode_t mode)
  {
  	struct aa_ns *ns, *parent;
  	/* TODO: improve permission check */
  	struct aa_label *label;
  	int error;
  
  	label = begin_current_label_crit_section();
  	error = aa_may_manage_policy(label, NULL, AA_MAY_LOAD_POLICY);
  	end_current_label_crit_section(label);
  	if (error)
  		return error;
  
  	parent = aa_get_ns(dir->i_private);
  	AA_BUG(d_inode(ns_subns_dir(parent)) != dir);
  
  	/* we have to unlock and then relock to get locking order right
  	 * for pin_fs
  	 */
  	inode_unlock(dir);
  	error = simple_pin_fs(&aafs_ops, &aafs_mnt, &aafs_count);
  	mutex_lock_nested(&parent->lock, parent->level);
  	inode_lock_nested(dir, I_MUTEX_PARENT);
  	if (error)
  		goto out;
  
  	error = __aafs_setup_d_inode(dir, dentry, mode | S_IFDIR,  NULL,
  				     NULL, NULL, NULL);
  	if (error)
  		goto out_pin;
  
  	ns = __aa_find_or_create_ns(parent, READ_ONCE(dentry->d_name.name),
  				    dentry);
  	if (IS_ERR(ns)) {
  		error = PTR_ERR(ns);
  		ns = NULL;
  	}
  
  	aa_put_ns(ns);		/* list ref remains */
  out_pin:
  	if (error)
  		simple_release_fs(&aafs_mnt, &aafs_count);
  out:
  	mutex_unlock(&parent->lock);
  	aa_put_ns(parent);
  
  	return error;
  }
  
  static int ns_rmdir_op(struct inode *dir, struct dentry *dentry)
  {
  	struct aa_ns *ns, *parent;
  	/* TODO: improve permission check */
  	struct aa_label *label;
  	int error;
  
  	label = begin_current_label_crit_section();
  	error = aa_may_manage_policy(label, NULL, AA_MAY_LOAD_POLICY);
  	end_current_label_crit_section(label);
  	if (error)
  		return error;
  
  	parent = aa_get_ns(dir->i_private);
  	/* rmdir calls the generic securityfs functions to remove files
  	 * from the apparmor dir. It is up to the apparmor ns locking
  	 * to avoid races.
  	 */
  	inode_unlock(dir);
  	inode_unlock(dentry->d_inode);
  
  	mutex_lock_nested(&parent->lock, parent->level);
  	ns = aa_get_ns(__aa_findn_ns(&parent->sub_ns, dentry->d_name.name,
  				     dentry->d_name.len));
  	if (!ns) {
  		error = -ENOENT;
  		goto out;
  	}
  	AA_BUG(ns_dir(ns) != dentry);
  
  	__aa_remove_ns(ns);
  	aa_put_ns(ns);
  
  out:
  	mutex_unlock(&parent->lock);
  	inode_lock_nested(dir, I_MUTEX_PARENT);
  	inode_lock(dentry->d_inode);
  	aa_put_ns(parent);
  
  	return error;
  }
  
  static const struct inode_operations ns_dir_inode_operations = {
  	.lookup		= simple_lookup,
  	.mkdir		= ns_mkdir_op,
  	.rmdir		= ns_rmdir_op,
  };
  
  static void __aa_fs_list_remove_rawdata(struct aa_ns *ns)
  {
  	struct aa_loaddata *ent, *tmp;
  
  	AA_BUG(!mutex_is_locked(&ns->lock));
  
  	list_for_each_entry_safe(ent, tmp, &ns->rawdata_list, list)
  		__aa_fs_remove_rawdata(ent);
  }
  
  /**
   *
   * Requires: @ns->lock held
   */
  void __aafs_ns_rmdir(struct aa_ns *ns)
  {
  	struct aa_ns *sub;
  	struct aa_profile *child;
  	int i;
  
  	if (!ns)
  		return;
  	AA_BUG(!mutex_is_locked(&ns->lock));
  
  	list_for_each_entry(child, &ns->base.profiles, base.list)
  		__aafs_profile_rmdir(child);
  
  	list_for_each_entry(sub, &ns->sub_ns, base.list) {
  		mutex_lock_nested(&sub->lock, sub->level);
  		__aafs_ns_rmdir(sub);
  		mutex_unlock(&sub->lock);
  	}
  
  	__aa_fs_list_remove_rawdata(ns);
  
  	if (ns_subns_dir(ns)) {
  		sub = d_inode(ns_subns_dir(ns))->i_private;
  		aa_put_ns(sub);
  	}
  	if (ns_subload(ns)) {
  		sub = d_inode(ns_subload(ns))->i_private;
  		aa_put_ns(sub);
  	}
  	if (ns_subreplace(ns)) {
  		sub = d_inode(ns_subreplace(ns))->i_private;
  		aa_put_ns(sub);
  	}
  	if (ns_subremove(ns)) {
  		sub = d_inode(ns_subremove(ns))->i_private;
  		aa_put_ns(sub);
  	}
  	if (ns_subrevision(ns)) {
  		sub = d_inode(ns_subrevision(ns))->i_private;
  		aa_put_ns(sub);
  	}
  
  	for (i = AAFS_NS_SIZEOF - 1; i >= 0; --i) {
  		aafs_remove(ns->dents[i]);
  		ns->dents[i] = NULL;
  	}
  }
  
  /* assumes cleanup in caller */
  static int __aafs_ns_mkdir_entries(struct aa_ns *ns, struct dentry *dir)
  {
  	struct dentry *dent;
  
  	AA_BUG(!ns);
  	AA_BUG(!dir);
  
  	dent = aafs_create_dir("profiles", dir);
  	if (IS_ERR(dent))
  		return PTR_ERR(dent);
  	ns_subprofs_dir(ns) = dent;
  
  	dent = aafs_create_dir("raw_data", dir);
  	if (IS_ERR(dent))
  		return PTR_ERR(dent);
  	ns_subdata_dir(ns) = dent;
  
  	dent = aafs_create_file("revision", 0444, dir, ns,
  				&aa_fs_ns_revision_fops);
  	if (IS_ERR(dent))
  		return PTR_ERR(dent);
  	aa_get_ns(ns);
  	ns_subrevision(ns) = dent;
  
  	dent = aafs_create_file(".load", 0640, dir, ns,
  				      &aa_fs_profile_load);
  	if (IS_ERR(dent))
  		return PTR_ERR(dent);
  	aa_get_ns(ns);
  	ns_subload(ns) = dent;
  
  	dent = aafs_create_file(".replace", 0640, dir, ns,
  				      &aa_fs_profile_replace);
  	if (IS_ERR(dent))
  		return PTR_ERR(dent);
  	aa_get_ns(ns);
  	ns_subreplace(ns) = dent;
  
  	dent = aafs_create_file(".remove", 0640, dir, ns,
  				      &aa_fs_profile_remove);
  	if (IS_ERR(dent))
  		return PTR_ERR(dent);
  	aa_get_ns(ns);
  	ns_subremove(ns) = dent;
  
  	  /* use create_dentry so we can supply private data */
  	dent = aafs_create("namespaces", S_IFDIR | 0755, dir, ns, NULL, NULL,
  			   &ns_dir_inode_operations);
  	if (IS_ERR(dent))
  		return PTR_ERR(dent);
  	aa_get_ns(ns);
  	ns_subns_dir(ns) = dent;
  
  	return 0;
  }
  
  /*
   * Requires: @ns->lock held
   */
  int __aafs_ns_mkdir(struct aa_ns *ns, struct dentry *parent, const char *name,
  		    struct dentry *dent)
  {
  	struct aa_ns *sub;
  	struct aa_profile *child;
  	struct dentry *dir;
  	int error;
  
  	AA_BUG(!ns);
  	AA_BUG(!parent);
  	AA_BUG(!mutex_is_locked(&ns->lock));
  
  	if (!name)
  		name = ns->base.name;
  
  	if (!dent) {
  		/* create ns dir if it doesn't already exist */
  		dent = aafs_create_dir(name, parent);
  		if (IS_ERR(dent))
  			goto fail;
  	} else
  		dget(dent);
  	ns_dir(ns) = dir = dent;
  	error = __aafs_ns_mkdir_entries(ns, dir);
  	if (error)
  		goto fail2;
  
  	/* profiles */
  	list_for_each_entry(child, &ns->base.profiles, base.list) {
  		error = __aafs_profile_mkdir(child, ns_subprofs_dir(ns));
  		if (error)
  			goto fail2;
  	}
  
  	/* subnamespaces */
  	list_for_each_entry(sub, &ns->sub_ns, base.list) {
  		mutex_lock_nested(&sub->lock, sub->level);
  		error = __aafs_ns_mkdir(sub, ns_subns_dir(ns), NULL, NULL);
  		mutex_unlock(&sub->lock);
  		if (error)
  			goto fail2;
  	}
  
  	return 0;
  
  fail:
  	error = PTR_ERR(dent);
  
  fail2:
  	__aafs_ns_rmdir(ns);
  
  	return error;
  }
  
  
  #define list_entry_is_head(pos, head, member) (&pos->member == (head))
  
  /**
   * __next_ns - find the next namespace to list
   * @root: root namespace to stop search at (NOT NULL)
   * @ns: current ns position (NOT NULL)
   *
   * Find the next namespace from @ns under @root and handle all locking needed
   * while switching current namespace.
   *
   * Returns: next namespace or NULL if at last namespace under @root
   * Requires: ns->parent->lock to be held
   * NOTE: will not unlock root->lock
   */
  static struct aa_ns *__next_ns(struct aa_ns *root, struct aa_ns *ns)
  {
  	struct aa_ns *parent, *next;
  
  	AA_BUG(!root);
  	AA_BUG(!ns);
  	AA_BUG(ns != root && !mutex_is_locked(&ns->parent->lock));
  
  	/* is next namespace a child */
  	if (!list_empty(&ns->sub_ns)) {
  		next = list_first_entry(&ns->sub_ns, typeof(*ns), base.list);
  		mutex_lock_nested(&next->lock, next->level);
  		return next;
  	}
  
  	/* check if the next ns is a sibling, parent, gp, .. */
  	parent = ns->parent;
  	while (ns != root) {
  		mutex_unlock(&ns->lock);
  		next = list_next_entry(ns, base.list);
  		if (!list_entry_is_head(next, &parent->sub_ns, base.list)) {
  			mutex_lock_nested(&next->lock, next->level);
  			return next;
  		}
  		ns = parent;
  		parent = parent->parent;
  	}
  
  	return NULL;
  }
  
  /**
   * __first_profile - find the first profile in a namespace
   * @root: namespace that is root of profiles being displayed (NOT NULL)
   * @ns: namespace to start in   (NOT NULL)
   *
   * Returns: unrefcounted profile or NULL if no profile
   * Requires: profile->ns.lock to be held
   */
  static struct aa_profile *__first_profile(struct aa_ns *root,
  					  struct aa_ns *ns)
  {
  	AA_BUG(!root);
  	AA_BUG(ns && !mutex_is_locked(&ns->lock));
  
  	for (; ns; ns = __next_ns(root, ns)) {
  		if (!list_empty(&ns->base.profiles))
  			return list_first_entry(&ns->base.profiles,
  						struct aa_profile, base.list);
  	}
  	return NULL;
  }
  
  /**
   * __next_profile - step to the next profile in a profile tree
   * @profile: current profile in tree (NOT NULL)
   *
   * Perform a depth first traversal on the profile tree in a namespace
   *
   * Returns: next profile or NULL if done
   * Requires: profile->ns.lock to be held
   */
  static struct aa_profile *__next_profile(struct aa_profile *p)
  {
  	struct aa_profile *parent;
  	struct aa_ns *ns = p->ns;
  
  	AA_BUG(!mutex_is_locked(&profiles_ns(p)->lock));
  
  	/* is next profile a child */
  	if (!list_empty(&p->base.profiles))
  		return list_first_entry(&p->base.profiles, typeof(*p),
  					base.list);
  
  	/* is next profile a sibling, parent sibling, gp, sibling, .. */
  	parent = rcu_dereference_protected(p->parent,
  					   mutex_is_locked(&p->ns->lock));
  	while (parent) {
  		p = list_next_entry(p, base.list);
  		if (!list_entry_is_head(p, &parent->base.profiles, base.list))
  			return p;
  		p = parent;
  		parent = rcu_dereference_protected(parent->parent,
  					    mutex_is_locked(&parent->ns->lock));
  	}
  
  	/* is next another profile in the namespace */
  	p = list_next_entry(p, base.list);
  	if (!list_entry_is_head(p, &ns->base.profiles, base.list))
  		return p;
  
  	return NULL;
  }
  
  /**
   * next_profile - step to the next profile in where ever it may be
   * @root: root namespace  (NOT NULL)
   * @profile: current profile  (NOT NULL)
   *
   * Returns: next profile or NULL if there isn't one
   */
  static struct aa_profile *next_profile(struct aa_ns *root,
  				       struct aa_profile *profile)
  {
  	struct aa_profile *next = __next_profile(profile);
  	if (next)
  		return next;
  
  	/* finished all profiles in namespace move to next namespace */
  	return __first_profile(root, __next_ns(root, profile->ns));
  }
  
  /**
   * p_start - start a depth first traversal of profile tree
   * @f: seq_file to fill
   * @pos: current position
   *
   * Returns: first profile under current namespace or NULL if none found
   *
   * acquires first ns->lock
   */
  static void *p_start(struct seq_file *f, loff_t *pos)
  {
  	struct aa_profile *profile = NULL;
  	struct aa_ns *root = aa_get_current_ns();
  	loff_t l = *pos;
  	f->private = root;
  
  	/* find the first profile */
  	mutex_lock_nested(&root->lock, root->level);
  	profile = __first_profile(root, root);
  
  	/* skip to position */
  	for (; profile && l > 0; l--)
  		profile = next_profile(root, profile);
  
  	return profile;
  }
  
  /**
   * p_next - read the next profile entry
   * @f: seq_file to fill
   * @p: profile previously returned
   * @pos: current position
   *
   * Returns: next profile after @p or NULL if none
   *
   * may acquire/release locks in namespace tree as necessary
   */
  static void *p_next(struct seq_file *f, void *p, loff_t *pos)
  {
  	struct aa_profile *profile = p;
  	struct aa_ns *ns = f->private;
  	(*pos)++;
  
  	return next_profile(ns, profile);
  }
  
  /**
   * p_stop - stop depth first traversal
   * @f: seq_file we are filling
   * @p: the last profile writen
   *
   * Release all locking done by p_start/p_next on namespace tree
   */
  static void p_stop(struct seq_file *f, void *p)
  {
  	struct aa_profile *profile = p;
  	struct aa_ns *root = f->private, *ns;
  
  	if (profile) {
  		for (ns = profile->ns; ns && ns != root; ns = ns->parent)
  			mutex_unlock(&ns->lock);
  	}
  	mutex_unlock(&root->lock);
  	aa_put_ns(root);
  }
  
  /**
   * seq_show_profile - show a profile entry
   * @f: seq_file to file
   * @p: current position (profile)    (NOT NULL)
   *
   * Returns: error on failure
   */
  static int seq_show_profile(struct seq_file *f, void *p)
  {
  	struct aa_profile *profile = (struct aa_profile *)p;
  	struct aa_ns *root = f->private;
  
  	aa_label_seq_xprint(f, root, &profile->label,
  			    FLAG_SHOW_MODE | FLAG_VIEW_SUBNS, GFP_KERNEL);
  	seq_putc(f, '\n');
  
  	return 0;
  }
  
  static const struct seq_operations aa_sfs_profiles_op = {
  	.start = p_start,
  	.next = p_next,
  	.stop = p_stop,
  	.show = seq_show_profile,
  };
  
  static int profiles_open(struct inode *inode, struct file *file)
  {
  	if (!policy_view_capable(NULL))
  		return -EACCES;
  
  	return seq_open(file, &aa_sfs_profiles_op);
  }
  
  static int profiles_release(struct inode *inode, struct file *file)
  {
  	return seq_release(inode, file);
  }
  
  static const struct file_operations aa_sfs_profiles_fops = {
  	.open = profiles_open,
  	.read = seq_read,
  	.llseek = seq_lseek,
  	.release = profiles_release,
  };
  
  
  /** Base file system setup **/
  static struct aa_sfs_entry aa_sfs_entry_file[] = {
  	AA_SFS_FILE_STRING("mask",
  			   "create read write exec append mmap_exec link lock"),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_ptrace[] = {
  	AA_SFS_FILE_STRING("mask", "read trace"),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_signal[] = {
  	AA_SFS_FILE_STRING("mask", AA_SFS_SIG_MASK),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_attach[] = {
  	AA_SFS_FILE_BOOLEAN("xattr", 1),
  	{ }
  };
  static struct aa_sfs_entry aa_sfs_entry_domain[] = {
  	AA_SFS_FILE_BOOLEAN("change_hat",	1),
  	AA_SFS_FILE_BOOLEAN("change_hatv",	1),
  	AA_SFS_FILE_BOOLEAN("change_onexec",	1),
  	AA_SFS_FILE_BOOLEAN("change_profile",	1),
  	AA_SFS_FILE_BOOLEAN("stack",		1),
  	AA_SFS_FILE_BOOLEAN("fix_binfmt_elf_mmap",	1),
  	AA_SFS_FILE_BOOLEAN("post_nnp_subset",	1),
  	AA_SFS_FILE_BOOLEAN("computed_longest_left",	1),
  	AA_SFS_DIR("attach_conditions",		aa_sfs_entry_attach),
  	AA_SFS_FILE_STRING("version", "1.2"),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_versions[] = {
  	AA_SFS_FILE_BOOLEAN("v5",	1),
  	AA_SFS_FILE_BOOLEAN("v6",	1),
  	AA_SFS_FILE_BOOLEAN("v7",	1),
  	AA_SFS_FILE_BOOLEAN("v8",	1),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_policy[] = {
  	AA_SFS_DIR("versions",			aa_sfs_entry_versions),
  	AA_SFS_FILE_BOOLEAN("set_load",		1),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_mount[] = {
  	AA_SFS_FILE_STRING("mask", "mount umount pivot_root"),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_ns[] = {
  	AA_SFS_FILE_BOOLEAN("profile",		1),
  	AA_SFS_FILE_BOOLEAN("pivot_root",	0),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_query_label[] = {
  	AA_SFS_FILE_STRING("perms", "allow deny audit quiet"),
  	AA_SFS_FILE_BOOLEAN("data",		1),
  	AA_SFS_FILE_BOOLEAN("multi_transaction",	1),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_query[] = {
  	AA_SFS_DIR("label",			aa_sfs_entry_query_label),
  	{ }
  };
  static struct aa_sfs_entry aa_sfs_entry_features[] = {
  	AA_SFS_DIR("policy",			aa_sfs_entry_policy),
  	AA_SFS_DIR("domain",			aa_sfs_entry_domain),
  	AA_SFS_DIR("file",			aa_sfs_entry_file),
  	AA_SFS_DIR("network_v8",		aa_sfs_entry_network),
  	AA_SFS_DIR("mount",			aa_sfs_entry_mount),
  	AA_SFS_DIR("namespaces",		aa_sfs_entry_ns),
  	AA_SFS_FILE_U64("capability",		VFS_CAP_FLAGS_MASK),
  	AA_SFS_DIR("rlimit",			aa_sfs_entry_rlimit),
  	AA_SFS_DIR("caps",			aa_sfs_entry_caps),
  	AA_SFS_DIR("ptrace",			aa_sfs_entry_ptrace),
  	AA_SFS_DIR("signal",			aa_sfs_entry_signal),
  	AA_SFS_DIR("query",			aa_sfs_entry_query),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry_apparmor[] = {
  	AA_SFS_FILE_FOPS(".access", 0666, &aa_sfs_access),
  	AA_SFS_FILE_FOPS(".stacked", 0444, &seq_ns_stacked_fops),
  	AA_SFS_FILE_FOPS(".ns_stacked", 0444, &seq_ns_nsstacked_fops),
  	AA_SFS_FILE_FOPS(".ns_level", 0444, &seq_ns_level_fops),
  	AA_SFS_FILE_FOPS(".ns_name", 0444, &seq_ns_name_fops),
  	AA_SFS_FILE_FOPS("profiles", 0444, &aa_sfs_profiles_fops),
  	AA_SFS_DIR("features", aa_sfs_entry_features),
  	{ }
  };
  
  static struct aa_sfs_entry aa_sfs_entry =
  	AA_SFS_DIR("apparmor", aa_sfs_entry_apparmor);
  
  /**
   * entry_create_file - create a file entry in the apparmor securityfs
   * @fs_file: aa_sfs_entry to build an entry for (NOT NULL)
   * @parent: the parent dentry in the securityfs
   *
   * Use entry_remove_file to remove entries created with this fn.
   */
  static int __init entry_create_file(struct aa_sfs_entry *fs_file,
  				    struct dentry *parent)
  {
  	int error = 0;
  
  	fs_file->dentry = securityfs_create_file(fs_file->name,
  						 S_IFREG | fs_file->mode,
  						 parent, fs_file,
  						 fs_file->file_ops);
  	if (IS_ERR(fs_file->dentry)) {
  		error = PTR_ERR(fs_file->dentry);
  		fs_file->dentry = NULL;
  	}
  	return error;
  }
  
  static void __init entry_remove_dir(struct aa_sfs_entry *fs_dir);
  /**
   * entry_create_dir - recursively create a directory entry in the securityfs
   * @fs_dir: aa_sfs_entry (and all child entries) to build (NOT NULL)
   * @parent: the parent dentry in the securityfs
   *
   * Use entry_remove_dir to remove entries created with this fn.
   */
  static int __init entry_create_dir(struct aa_sfs_entry *fs_dir,
  				   struct dentry *parent)
  {
  	struct aa_sfs_entry *fs_file;
  	struct dentry *dir;
  	int error;
  
  	dir = securityfs_create_dir(fs_dir->name, parent);
  	if (IS_ERR(dir))
  		return PTR_ERR(dir);
  	fs_dir->dentry = dir;
  
  	for (fs_file = fs_dir->v.files; fs_file && fs_file->name; ++fs_file) {
  		if (fs_file->v_type == AA_SFS_TYPE_DIR)
  			error = entry_create_dir(fs_file, fs_dir->dentry);
  		else
  			error = entry_create_file(fs_file, fs_dir->dentry);
  		if (error)
  			goto failed;
  	}
  
  	return 0;
  
  failed:
  	entry_remove_dir(fs_dir);
  
  	return error;
  }
  
  /**
   * entry_remove_file - drop a single file entry in the apparmor securityfs
   * @fs_file: aa_sfs_entry to detach from the securityfs (NOT NULL)
   */
  static void __init entry_remove_file(struct aa_sfs_entry *fs_file)
  {
  	if (!fs_file->dentry)
  		return;
  
  	securityfs_remove(fs_file->dentry);
  	fs_file->dentry = NULL;
  }
  
  /**
   * entry_remove_dir - recursively drop a directory entry from the securityfs
   * @fs_dir: aa_sfs_entry (and all child entries) to detach (NOT NULL)
   */
  static void __init entry_remove_dir(struct aa_sfs_entry *fs_dir)
  {
  	struct aa_sfs_entry *fs_file;
  
  	for (fs_file = fs_dir->v.files; fs_file && fs_file->name; ++fs_file) {
  		if (fs_file->v_type == AA_SFS_TYPE_DIR)
  			entry_remove_dir(fs_file);
  		else
  			entry_remove_file(fs_file);
  	}
  
  	entry_remove_file(fs_dir);
  }
  
  /**
   * aa_destroy_aafs - cleanup and free aafs
   *
   * releases dentries allocated by aa_create_aafs
   */
  void __init aa_destroy_aafs(void)
  {
  	entry_remove_dir(&aa_sfs_entry);
  }
  
  
  #define NULL_FILE_NAME ".null"
  struct path aa_null;
  
  static int aa_mk_null_file(struct dentry *parent)
  {
  	struct vfsmount *mount = NULL;
  	struct dentry *dentry;
  	struct inode *inode;
  	int count = 0;
  	int error = simple_pin_fs(parent->d_sb->s_type, &mount, &count);
  
  	if (error)
  		return error;
  
  	inode_lock(d_inode(parent));
  	dentry = lookup_one_len(NULL_FILE_NAME, parent, strlen(NULL_FILE_NAME));
  	if (IS_ERR(dentry)) {
  		error = PTR_ERR(dentry);
  		goto out;
  	}
  	inode = new_inode(parent->d_inode->i_sb);
  	if (!inode) {
  		error = -ENOMEM;
  		goto out1;
  	}
  
  	inode->i_ino = get_next_ino();
  	inode->i_mode = S_IFCHR | S_IRUGO | S_IWUGO;
  	inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
  	init_special_inode(inode, S_IFCHR | S_IRUGO | S_IWUGO,
  			   MKDEV(MEM_MAJOR, 3));
  	d_instantiate(dentry, inode);
  	aa_null.dentry = dget(dentry);
  	aa_null.mnt = mntget(mount);
  
  	error = 0;
  
  out1:
  	dput(dentry);
  out:
  	inode_unlock(d_inode(parent));
  	simple_release_fs(&mount, &count);
  	return error;
  }
  
  
  
  static const char *policy_get_link(struct dentry *dentry,
  				   struct inode *inode,
  				   struct delayed_call *done)
  {
  	struct aa_ns *ns;
  	struct path path;
  
  	if (!dentry)
  		return ERR_PTR(-ECHILD);
  	ns = aa_get_current_ns();
  	path.mnt = mntget(aafs_mnt);
  	path.dentry = dget(ns_dir(ns));
  	nd_jump_link(&path);
  	aa_put_ns(ns);
  
  	return NULL;
  }
  
  static int policy_readlink(struct dentry *dentry, char __user *buffer,
  			   int buflen)
  {
  	char name[32];
  	int res;
  
  	res = snprintf(name, sizeof(name), "%s:[%lu]", AAFS_NAME,
  		       d_inode(dentry)->i_ino);
  	if (res > 0 && res < sizeof(name))
  		res = readlink_copy(buffer, buflen, name);
  	else
  		res = -ENOENT;
  
  	return res;
  }
  
  static const struct inode_operations policy_link_iops = {
  	.readlink	= policy_readlink,
  	.get_link	= policy_get_link,
  };
  
  
  /**
   * aa_create_aafs - create the apparmor security filesystem
   *
   * dentries created here are released by aa_destroy_aafs
   *
   * Returns: error on failure
   */
  static int __init aa_create_aafs(void)
  {
  	struct dentry *dent;
  	int error;
  
  	if (!apparmor_initialized)
  		return 0;
  
  	if (aa_sfs_entry.dentry) {
  		AA_ERROR("%s: AppArmor securityfs already exists\n", __func__);
  		return -EEXIST;
  	}
  
  	/* setup apparmorfs used to virtualize policy/ */
  	aafs_mnt = kern_mount(&aafs_ops);
  	if (IS_ERR(aafs_mnt))
  		panic("can't set apparmorfs up\n");
  	aafs_mnt->mnt_sb->s_flags &= ~SB_NOUSER;
  
  	/* Populate fs tree. */
  	error = entry_create_dir(&aa_sfs_entry, NULL);
  	if (error)
  		goto error;
  
  	dent = securityfs_create_file(".load", 0666, aa_sfs_entry.dentry,
  				      NULL, &aa_fs_profile_load);
  	if (IS_ERR(dent))
  		goto dent_error;
  	ns_subload(root_ns) = dent;
  
  	dent = securityfs_create_file(".replace", 0666, aa_sfs_entry.dentry,
  				      NULL, &aa_fs_profile_replace);
  	if (IS_ERR(dent))
  		goto dent_error;
  	ns_subreplace(root_ns) = dent;
  
  	dent = securityfs_create_file(".remove", 0666, aa_sfs_entry.dentry,
  				      NULL, &aa_fs_profile_remove);
  	if (IS_ERR(dent))
  		goto dent_error;
  	ns_subremove(root_ns) = dent;
  
  	dent = securityfs_create_file("revision", 0444, aa_sfs_entry.dentry,
  				      NULL, &aa_fs_ns_revision_fops);
  	if (IS_ERR(dent))
  		goto dent_error;
  	ns_subrevision(root_ns) = dent;
  
  	/* policy tree referenced by magic policy symlink */
  	mutex_lock_nested(&root_ns->lock, root_ns->level);
  	error = __aafs_ns_mkdir(root_ns, aafs_mnt->mnt_root, ".policy",
  				aafs_mnt->mnt_root);
  	mutex_unlock(&root_ns->lock);
  	if (error)
  		goto error;
  
  	/* magic symlink similar to nsfs redirects based on task policy */
  	dent = securityfs_create_symlink("policy", aa_sfs_entry.dentry,
  					 NULL, &policy_link_iops);
  	if (IS_ERR(dent))
  		goto dent_error;
  
  	error = aa_mk_null_file(aa_sfs_entry.dentry);
  	if (error)
  		goto error;
  
  	/* TODO: add default profile to apparmorfs */
  
  	/* Report that AppArmor fs is enabled */
  	aa_info_message("AppArmor Filesystem Enabled");
  	return 0;
  
  dent_error:
  	error = PTR_ERR(dent);
  error:
  	aa_destroy_aafs();
  	AA_ERROR("Error creating AppArmor securityfs\n");
  	return error;
  }
  
  fs_initcall(aa_create_aafs);
  