[mirror_ubuntu-bionic-kernel.git] / security / apparmor / apparmorfs.c

/*
 * AppArmor security module
 *
 * This file contains AppArmor /sys/kernel/security/apparmor interface functions
 *
 * Copyright (C) 1998-2008 Novell/SUSE
 * Copyright 2009-2010 Canonical Ltd.
 *
 * 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 of the
 * License.
 */

#include <linux/ctype.h>
#include <linux/security.h>
#include <linux/vmalloc.h>
#include <linux/module.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/context.h"
#include "include/crypto.h"
#include "include/ipc.h"
#include "include/policy_ns.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)
{
        struct inode *inode = d_inode(dentry);

        seq_printf(seq, "%s:[%lu]", AAFS_NAME, inode->i_ino);
        return 0;
}

static void aafs_evict_inode(struct inode *inode)
{
        truncate_inode_pages_final(&inode->i_data);
        clear_inode(inode);
        if (S_ISLNK(inode->i_mode))
                kfree(inode->i_link);
}

static const struct super_operations aafs_super_ops = {
        .statfs = simple_statfs,
        .evict_inode = aafs_evict_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);
                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 unsigned int ns_revision_poll(struct file *file, poll_table *pt)
{
        struct aa_revision *rev = file->private_data;
        unsigned int 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 |= POLLIN | POLLRDNORM;
                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);
                tmp = nullperms;
                if (state) {
                        struct path_cond cond = { };

                        tmp = aa_compute_fperms(dfa, state, &cond);
                }
        } else if (profile->policy.dfa) {
                if (!PROFILE_MEDIATES_SAFE(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);
                else
                        tmp = nullperms;
        }
        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_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_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),
        { }
};

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_dbus[] = {
        AA_SFS_FILE_STRING("mask", "acquire send receive"),
        { }
};

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",                   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("dbus",                      aa_sfs_entry_dbus),
        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 ns_get_name(char *buf, size_t size, struct aa_ns *ns,
                       struct inode *inode)
{
        int res = snprintf(buf, size, "%s:[%lu]", AAFS_NAME, inode->i_ino);

        if (res < 0 || res >= size)
                res = -ENOENT;

        return res;
}

static int policy_readlink(struct dentry *dentry, char __user *buffer,
                           int buflen)
{
        struct aa_ns *ns;
        char name[32];
        int res;

        ns = aa_get_current_ns();
        res = ns_get_name(name, sizeof(name), ns, d_inode(dentry));
        if (res >= 0)
                res = readlink_copy(buffer, buflen, name);
        aa_put_ns(ns);

        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)) {
                error = PTR_ERR(dent);
                goto 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)) {
                error = PTR_ERR(dent);
                goto 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)) {
                error = PTR_ERR(dent);
                goto 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)) {
                error = PTR_ERR(dent);
                goto 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)) {
                error = PTR_ERR(dent);
                goto 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;

error:
        aa_destroy_aafs();
        AA_ERROR("Error creating AppArmor securityfs\n");
        return error;
}

fs_initcall(aa_create_aafs);