lsm.c

Go to the documentation of this file.

/*
 * AppArmor security module
 *
 * This file contains AppArmor LSM hooks.
 *
 * 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/security.h>
#include <linux/moduleparam.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/ptrace.h>
#include <linux/ctype.h>
#include <linux/sysctl.h>
#include <linux/audit.h>
#include <linux/user_namespace.h>
#include <net/sock.h>

#include "include/apparmor.h"
#include "include/apparmorfs.h"
#include "include/audit.h"
#include "include/capability.h"
#include "include/context.h"
#include "include/file.h"
#include "include/ipc.h"
#include "include/path.h"
#include "include/policy.h"
#include "include/procattr.h"

/* Flag indicating whether initialization completed */
int apparmor_initialized __initdata;

/*
 * LSM hook functions
 */

/*
 * free the associated aa_task_cxt and put its profiles
 */
static void apparmor_cred_free(struct cred *cred)
{
    aa_free_task_context(cred->security);
    cred->security = NULL;
}

/*
 * allocate the apparmor part of blank credentials
 */
static int apparmor_cred_alloc_blank(struct cred *cred, gfp_t gfp)
{
    /* freed by apparmor_cred_free */
    struct aa_task_cxt *cxt = aa_alloc_task_context(gfp);
    if (!cxt)
        return -ENOMEM;

    cred->security = cxt;
    return 0;
}

/*
 * prepare new aa_task_cxt for modification by prepare_cred block
 */
static int apparmor_cred_prepare(struct cred *new, const struct cred *old,
                 gfp_t gfp)
{
    /* freed by apparmor_cred_free */
    struct aa_task_cxt *cxt = aa_alloc_task_context(gfp);
    if (!cxt)
        return -ENOMEM;

    aa_dup_task_context(cxt, old->security);
    new->security = cxt;
    return 0;
}

/*
 * transfer the apparmor data to a blank set of creds
 */
static void apparmor_cred_transfer(struct cred *new, const struct cred *old)
{
    const struct aa_task_cxt *old_cxt = old->security;
    struct aa_task_cxt *new_cxt = new->security;

    aa_dup_task_context(new_cxt, old_cxt);
}

static int apparmor_ptrace_access_check(struct task_struct *child,
                    unsigned int mode)
{
    int error = cap_ptrace_access_check(child, mode);
    if (error)
        return error;

    return aa_ptrace(current, child, mode);
}

static int apparmor_ptrace_traceme(struct task_struct *parent)
{
    int error = cap_ptrace_traceme(parent);
    if (error)
        return error;

    return aa_ptrace(parent, current, PTRACE_MODE_ATTACH);
}

/* Derived from security/commoncap.c:cap_capget */
static int apparmor_capget(struct task_struct *target, kernel_cap_t *effective,
               kernel_cap_t *inheritable, kernel_cap_t *permitted)
{
    struct aa_profile *profile;
    const struct cred *cred;

    rcu_read_lock();
    cred = __task_cred(target);
    profile = aa_cred_profile(cred);

    *effective = cred->cap_effective;
    *inheritable = cred->cap_inheritable;
    *permitted = cred->cap_permitted;

    if (!unconfined(profile) && !COMPLAIN_MODE(profile)) {
        *effective = cap_intersect(*effective, profile->caps.allow);
        *permitted = cap_intersect(*permitted, profile->caps.allow);
    }
    rcu_read_unlock();

    return 0;
}

static int apparmor_capable(const struct cred *cred, struct user_namespace *ns,
                int cap, int audit)
{
    struct aa_profile *profile;
    /* cap_capable returns 0 on success, else -EPERM */
    int error = cap_capable(cred, ns, cap, audit);
    if (!error) {
        profile = aa_cred_profile(cred);
        if (!unconfined(profile))
            error = aa_capable(current, profile, cap, audit);
    }
    return error;
}

static int common_perm(int op, struct path *path, u32 mask,
               struct path_cond *cond)
{
    struct aa_profile *profile;
    int error = 0;

    profile = __aa_current_profile();
    if (!unconfined(profile))
        error = aa_path_perm(op, profile, path, 0, mask, cond);

    return error;
}

static int common_perm_dir_dentry(int op, struct path *dir,
                  struct dentry *dentry, u32 mask,
                  struct path_cond *cond)
{
    struct path path = { dir->mnt, dentry };

    return common_perm(op, &path, mask, cond);
}

static int common_perm_mnt_dentry(int op, struct vfsmount *mnt,
                  struct dentry *dentry, u32 mask)
{
    struct path path = { mnt, dentry };
    struct path_cond cond = { dentry->d_inode->i_uid,
                  dentry->d_inode->i_mode
    };

    return common_perm(op, &path, mask, &cond);
}

static int common_perm_rm(int op, struct path *dir,
              struct dentry *dentry, u32 mask)
{
    struct inode *inode = dentry->d_inode;
    struct path_cond cond = { };

    if (!inode || !dir->mnt || !mediated_filesystem(inode))
        return 0;

    cond.uid = inode->i_uid;
    cond.mode = inode->i_mode;

    return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
}

static int common_perm_create(int op, struct path *dir, struct dentry *dentry,
                  u32 mask, umode_t mode)
{
    struct path_cond cond = { current_fsuid(), mode };

    if (!dir->mnt || !mediated_filesystem(dir->dentry->d_inode))
        return 0;

    return common_perm_dir_dentry(op, dir, dentry, mask, &cond);
}

static int apparmor_path_unlink(struct path *dir, struct dentry *dentry)
{
    return common_perm_rm(OP_UNLINK, dir, dentry, AA_MAY_DELETE);
}

static int apparmor_path_mkdir(struct path *dir, struct dentry *dentry,
                   umode_t mode)
{
    return common_perm_create(OP_MKDIR, dir, dentry, AA_MAY_CREATE,
                  S_IFDIR);
}

static int apparmor_path_rmdir(struct path *dir, struct dentry *dentry)
{
    return common_perm_rm(OP_RMDIR, dir, dentry, AA_MAY_DELETE);
}

static int apparmor_path_mknod(struct path *dir, struct dentry *dentry,
                   umode_t mode, unsigned int dev)
{
    return common_perm_create(OP_MKNOD, dir, dentry, AA_MAY_CREATE, mode);
}

static int apparmor_path_truncate(struct path *path)
{
    struct path_cond cond = { path->dentry->d_inode->i_uid,
                  path->dentry->d_inode->i_mode
    };

    if (!path->mnt || !mediated_filesystem(path->dentry->d_inode))
        return 0;

    return common_perm(OP_TRUNC, path, MAY_WRITE | AA_MAY_META_WRITE,
               &cond);
}

static int apparmor_path_symlink(struct path *dir, struct dentry *dentry,
                 const char *old_name)
{
    return common_perm_create(OP_SYMLINK, dir, dentry, AA_MAY_CREATE,
                  S_IFLNK);
}

static int apparmor_path_link(struct dentry *old_dentry, struct path *new_dir,
                  struct dentry *new_dentry)
{
    struct aa_profile *profile;
    int error = 0;

    if (!mediated_filesystem(old_dentry->d_inode))
        return 0;

    profile = aa_current_profile();
    if (!unconfined(profile))
        error = aa_path_link(profile, old_dentry, new_dir, new_dentry);
    return error;
}

static int apparmor_path_rename(struct path *old_dir, struct dentry *old_dentry,
                struct path *new_dir, struct dentry *new_dentry)
{
    struct aa_profile *profile;
    int error = 0;

    if (!mediated_filesystem(old_dentry->d_inode))
        return 0;

    profile = aa_current_profile();
    if (!unconfined(profile)) {
        struct path old_path = { old_dir->mnt, old_dentry };
        struct path new_path = { new_dir->mnt, new_dentry };
        struct path_cond cond = { old_dentry->d_inode->i_uid,
                      old_dentry->d_inode->i_mode
        };

        error = aa_path_perm(OP_RENAME_SRC, profile, &old_path, 0,
                     MAY_READ | AA_MAY_META_READ | MAY_WRITE |
                     AA_MAY_META_WRITE | AA_MAY_DELETE,
                     &cond);
        if (!error)
            error = aa_path_perm(OP_RENAME_DEST, profile, &new_path,
                         0, MAY_WRITE | AA_MAY_META_WRITE |
                         AA_MAY_CREATE, &cond);

    }
    return error;
}

static int apparmor_path_chmod(struct path *path, umode_t mode)
{
    if (!mediated_filesystem(path->dentry->d_inode))
        return 0;

    return common_perm_mnt_dentry(OP_CHMOD, path->mnt, path->dentry, AA_MAY_CHMOD);
}

static int apparmor_path_chown(struct path *path, kuid_t uid, kgid_t gid)
{
    struct path_cond cond =  { path->dentry->d_inode->i_uid,
                   path->dentry->d_inode->i_mode
    };

    if (!mediated_filesystem(path->dentry->d_inode))
        return 0;

    return common_perm(OP_CHOWN, path, AA_MAY_CHOWN, &cond);
}

static int apparmor_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
{
    if (!mediated_filesystem(dentry->d_inode))
        return 0;

    return common_perm_mnt_dentry(OP_GETATTR, mnt, dentry,
                      AA_MAY_META_READ);
}

static int apparmor_file_open(struct file *file, const struct cred *cred)
{
    struct aa_file_cxt *fcxt = file->f_security;
    struct aa_profile *profile;
    int error = 0;

    if (!mediated_filesystem(file->f_path.dentry->d_inode))
        return 0;

    /* If in exec, permission is handled by bprm hooks.
     * Cache permissions granted by the previous exec check, with
     * implicit read and executable mmap which are required to
     * actually execute the image.
     */
    if (current->in_execve) {
        fcxt->allow = MAY_EXEC | MAY_READ | AA_EXEC_MMAP;
        return 0;
    }

    profile = aa_cred_profile(cred);
    if (!unconfined(profile)) {
        struct inode *inode = file->f_path.dentry->d_inode;
        struct path_cond cond = { inode->i_uid, inode->i_mode };

        error = aa_path_perm(OP_OPEN, profile, &file->f_path, 0,
                     aa_map_file_to_perms(file), &cond);
        /* todo cache full allowed permissions set and state */
        fcxt->allow = aa_map_file_to_perms(file);
    }

    return error;
}

static int apparmor_file_alloc_security(struct file *file)
{
    /* freed by apparmor_file_free_security */
    file->f_security = aa_alloc_file_context(GFP_KERNEL);
    if (!file->f_security)
        return -ENOMEM;
    return 0;

}

static void apparmor_file_free_security(struct file *file)
{
    struct aa_file_cxt *cxt = file->f_security;

    aa_free_file_context(cxt);
}

static int common_file_perm(int op, struct file *file, u32 mask)
{
    struct aa_file_cxt *fcxt = file->f_security;
    struct aa_profile *profile, *fprofile = aa_cred_profile(file->f_cred);
    int error = 0;

    BUG_ON(!fprofile);

    if (!file->f_path.mnt ||
        !mediated_filesystem(file->f_path.dentry->d_inode))
        return 0;

    profile = __aa_current_profile();

    /* revalidate access, if task is unconfined, or the cached cred
     * doesn't match or if the request is for more permissions than
     * was granted.
     *
     * Note: the test for !unconfined(fprofile) is to handle file
     *       delegation from unconfined tasks
     */
    if (!unconfined(profile) && !unconfined(fprofile) &&
        ((fprofile != profile) || (mask & ~fcxt->allow)))
        error = aa_file_perm(op, profile, file, mask);

    return error;
}

static int apparmor_file_permission(struct file *file, int mask)
{
    return common_file_perm(OP_FPERM, file, mask);
}

static int apparmor_file_lock(struct file *file, unsigned int cmd)
{
    u32 mask = AA_MAY_LOCK;

    if (cmd == F_WRLCK)
        mask |= MAY_WRITE;

    return common_file_perm(OP_FLOCK, file, mask);
}

static int common_mmap(int op, struct file *file, unsigned long prot,
               unsigned long flags)
{
    struct dentry *dentry;
    int mask = 0;

    if (!file || !file->f_security)
        return 0;

    if (prot & PROT_READ)
        mask |= MAY_READ;
    /*
     * Private mappings don't require write perms since they don't
     * write back to the files
     */
    if ((prot & PROT_WRITE) && !(flags & MAP_PRIVATE))
        mask |= MAY_WRITE;
    if (prot & PROT_EXEC)
        mask |= AA_EXEC_MMAP;

    dentry = file->f_path.dentry;
    return common_file_perm(op, file, mask);
}

static int apparmor_mmap_file(struct file *file, unsigned long reqprot,
                  unsigned long prot, unsigned long flags)
{
    return common_mmap(OP_FMMAP, file, prot, flags);
}

static int apparmor_file_mprotect(struct vm_area_struct *vma,
                  unsigned long reqprot, unsigned long prot)
{
    return common_mmap(OP_FMPROT, vma->vm_file, prot,
               !(vma->vm_flags & VM_SHARED) ? MAP_PRIVATE : 0);
}

static int apparmor_getprocattr(struct task_struct *task, char *name,
                char **value)
{
    int error = -ENOENT;
    struct aa_profile *profile;
    /* released below */
    const struct cred *cred = get_task_cred(task);
    struct aa_task_cxt *cxt = cred->security;
    profile = aa_cred_profile(cred);

    if (strcmp(name, "current") == 0)
        error = aa_getprocattr(aa_newest_version(cxt->profile),
                       value);
    else if (strcmp(name, "prev") == 0  && cxt->previous)
        error = aa_getprocattr(aa_newest_version(cxt->previous),
                       value);
    else if (strcmp(name, "exec") == 0 && cxt->onexec)
        error = aa_getprocattr(aa_newest_version(cxt->onexec),
                       value);
    else
        error = -EINVAL;

    put_cred(cred);

    return error;
}

static int apparmor_setprocattr(struct task_struct *task, char *name,
                void *value, size_t size)
{
    char *command, *args = value;
    size_t arg_size;
    int error;

    if (size == 0)
        return -EINVAL;
    /* args points to a PAGE_SIZE buffer, AppArmor requires that
     * the buffer must be null terminated or have size <= PAGE_SIZE -1
     * so that AppArmor can null terminate them
     */
    if (args[size - 1] != '\0') {
        if (size == PAGE_SIZE)
            return -EINVAL;
        args[size] = '\0';
    }

    /* task can only write its own attributes */
    if (current != task)
        return -EACCES;

    args = value;
    args = strim(args);
    command = strsep(&args, " ");
    if (!args)
        return -EINVAL;
    args = skip_spaces(args);
    if (!*args)
        return -EINVAL;

    arg_size = size - (args - (char *) value);
    if (strcmp(name, "current") == 0) {
        if (strcmp(command, "changehat") == 0) {
            error = aa_setprocattr_changehat(args, arg_size,
                             !AA_DO_TEST);
        } else if (strcmp(command, "permhat") == 0) {
            error = aa_setprocattr_changehat(args, arg_size,
                             AA_DO_TEST);
        } else if (strcmp(command, "changeprofile") == 0) {
            error = aa_setprocattr_changeprofile(args, !AA_ONEXEC,
                                 !AA_DO_TEST);
        } else if (strcmp(command, "permprofile") == 0) {
            error = aa_setprocattr_changeprofile(args, !AA_ONEXEC,
                                 AA_DO_TEST);
        } else if (strcmp(command, "permipc") == 0) {
            error = aa_setprocattr_permipc(args);
        } else {
            struct common_audit_data sa;
            struct apparmor_audit_data aad = {0,};
            sa.type = LSM_AUDIT_DATA_NONE;
            sa.aad = &aad;
            aad.op = OP_SETPROCATTR;
            aad.info = name;
            aad.error = -EINVAL;
            return aa_audit(AUDIT_APPARMOR_DENIED,
                    __aa_current_profile(), GFP_KERNEL,
                    &sa, NULL);
        }
    } else if (strcmp(name, "exec") == 0) {
        error = aa_setprocattr_changeprofile(args, AA_ONEXEC,
                             !AA_DO_TEST);
    } else {
        /* only support the "current" and "exec" process attributes */
        return -EINVAL;
    }
    if (!error)
        error = size;
    return error;
}

static int apparmor_task_setrlimit(struct task_struct *task,
        unsigned int resource, struct rlimit *new_rlim)
{
    struct aa_profile *profile = __aa_current_profile();
    int error = 0;

    if (!unconfined(profile))
        error = aa_task_setrlimit(profile, task, resource, new_rlim);

    return error;
}

static struct security_operations apparmor_ops = {
    .name =             "apparmor",

    .ptrace_access_check =      apparmor_ptrace_access_check,
    .ptrace_traceme =       apparmor_ptrace_traceme,
    .capget =           apparmor_capget,
    .capable =          apparmor_capable,

    .path_link =            apparmor_path_link,
    .path_unlink =          apparmor_path_unlink,
    .path_symlink =         apparmor_path_symlink,
    .path_mkdir =           apparmor_path_mkdir,
    .path_rmdir =           apparmor_path_rmdir,
    .path_mknod =           apparmor_path_mknod,
    .path_rename =          apparmor_path_rename,
    .path_chmod =           apparmor_path_chmod,
    .path_chown =           apparmor_path_chown,
    .path_truncate =        apparmor_path_truncate,
    .inode_getattr =                apparmor_inode_getattr,

    .file_open =            apparmor_file_open,
    .file_permission =      apparmor_file_permission,
    .file_alloc_security =      apparmor_file_alloc_security,
    .file_free_security =       apparmor_file_free_security,
    .mmap_file =            apparmor_mmap_file,
    .mmap_addr =            cap_mmap_addr,
    .file_mprotect =        apparmor_file_mprotect,
    .file_lock =            apparmor_file_lock,

    .getprocattr =          apparmor_getprocattr,
    .setprocattr =          apparmor_setprocattr,

    .cred_alloc_blank =     apparmor_cred_alloc_blank,
    .cred_free =            apparmor_cred_free,
    .cred_prepare =         apparmor_cred_prepare,
    .cred_transfer =        apparmor_cred_transfer,

    .bprm_set_creds =       apparmor_bprm_set_creds,
    .bprm_committing_creds =    apparmor_bprm_committing_creds,
    .bprm_committed_creds =     apparmor_bprm_committed_creds,
    .bprm_secureexec =      apparmor_bprm_secureexec,

    .task_setrlimit =       apparmor_task_setrlimit,
};

/*
 * AppArmor sysfs module parameters
 */

static int param_set_aabool(const char *val, const struct kernel_param *kp);
static int param_get_aabool(char *buffer, const struct kernel_param *kp);
#define param_check_aabool param_check_bool
static struct kernel_param_ops param_ops_aabool = {
    .set = param_set_aabool,
    .get = param_get_aabool
};

static int param_set_aauint(const char *val, const struct kernel_param *kp);
static int param_get_aauint(char *buffer, const struct kernel_param *kp);
#define param_check_aauint param_check_uint
static struct kernel_param_ops param_ops_aauint = {
    .set = param_set_aauint,
    .get = param_get_aauint
};

static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp);
static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp);
#define param_check_aalockpolicy param_check_bool
static struct kernel_param_ops param_ops_aalockpolicy = {
    .set = param_set_aalockpolicy,
    .get = param_get_aalockpolicy
};

static int param_set_audit(const char *val, struct kernel_param *kp);
static int param_get_audit(char *buffer, struct kernel_param *kp);

static int param_set_mode(const char *val, struct kernel_param *kp);
static int param_get_mode(char *buffer, struct kernel_param *kp);

/* Flag values, also controllable via /sys/module/apparmor/parameters
 * We define special types as we want to do additional mediation.
 */

/* AppArmor global enforcement switch - complain, enforce, kill */
enum profile_mode aa_g_profile_mode = APPARMOR_ENFORCE;
module_param_call(mode, param_set_mode, param_get_mode,
          &aa_g_profile_mode, S_IRUSR | S_IWUSR);

/* Debug mode */
bool aa_g_debug;
module_param_named(debug, aa_g_debug, aabool, S_IRUSR | S_IWUSR);

/* Audit mode */
enum audit_mode aa_g_audit;
module_param_call(audit, param_set_audit, param_get_audit,
          &aa_g_audit, S_IRUSR | S_IWUSR);

/* Determines if audit header is included in audited messages.  This
 * provides more context if the audit daemon is not running
 */
bool aa_g_audit_header = 1;
module_param_named(audit_header, aa_g_audit_header, aabool,
           S_IRUSR | S_IWUSR);

/* lock out loading/removal of policy
 * TODO: add in at boot loading of policy, which is the only way to
 *       load policy, if lock_policy is set
 */
bool aa_g_lock_policy;
module_param_named(lock_policy, aa_g_lock_policy, aalockpolicy,
           S_IRUSR | S_IWUSR);

/* Syscall logging mode */
bool aa_g_logsyscall;
module_param_named(logsyscall, aa_g_logsyscall, aabool, S_IRUSR | S_IWUSR);

/* Maximum pathname length before accesses will start getting rejected */
unsigned int aa_g_path_max = 2 * PATH_MAX;
module_param_named(path_max, aa_g_path_max, aauint, S_IRUSR | S_IWUSR);

/* Determines how paranoid loading of policy is and how much verification
 * on the loaded policy is done.
 */
bool aa_g_paranoid_load = 1;
module_param_named(paranoid_load, aa_g_paranoid_load, aabool,
           S_IRUSR | S_IWUSR);

/* Boot time disable flag */
static bool apparmor_enabled = CONFIG_SECURITY_APPARMOR_BOOTPARAM_VALUE;
module_param_named(enabled, apparmor_enabled, aabool, S_IRUSR);

static int __init apparmor_enabled_setup(char *str)
{
    unsigned long enabled;
    int error = strict_strtoul(str, 0, &enabled);
    if (!error)
        apparmor_enabled = enabled ? 1 : 0;
    return 1;
}

__setup("apparmor=", apparmor_enabled_setup);

/* set global flag turning off the ability to load policy */
static int param_set_aalockpolicy(const char *val, const struct kernel_param *kp)
{
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;
    if (aa_g_lock_policy)
        return -EACCES;
    return param_set_bool(val, kp);
}

static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp)
{
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;
    return param_get_bool(buffer, kp);
}

static int param_set_aabool(const char *val, const struct kernel_param *kp)
{
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;
    return param_set_bool(val, kp);
}

static int param_get_aabool(char *buffer, const struct kernel_param *kp)
{
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;
    return param_get_bool(buffer, kp);
}

static int param_set_aauint(const char *val, const struct kernel_param *kp)
{
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;
    return param_set_uint(val, kp);
}

static int param_get_aauint(char *buffer, const struct kernel_param *kp)
{
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;
    return param_get_uint(buffer, kp);
}

static int param_get_audit(char *buffer, struct kernel_param *kp)
{
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;

    if (!apparmor_enabled)
        return -EINVAL;

    return sprintf(buffer, "%s", audit_mode_names[aa_g_audit]);
}

static int param_set_audit(const char *val, struct kernel_param *kp)
{
    int i;
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;

    if (!apparmor_enabled)
        return -EINVAL;

    if (!val)
        return -EINVAL;

    for (i = 0; i < AUDIT_MAX_INDEX; i++) {
        if (strcmp(val, audit_mode_names[i]) == 0) {
            aa_g_audit = i;
            return 0;
        }
    }

    return -EINVAL;
}

static int param_get_mode(char *buffer, struct kernel_param *kp)
{
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;

    if (!apparmor_enabled)
        return -EINVAL;

    return sprintf(buffer, "%s", profile_mode_names[aa_g_profile_mode]);
}

static int param_set_mode(const char *val, struct kernel_param *kp)
{
    int i;
    if (!capable(CAP_MAC_ADMIN))
        return -EPERM;

    if (!apparmor_enabled)
        return -EINVAL;

    if (!val)
        return -EINVAL;

    for (i = 0; i < APPARMOR_NAMES_MAX_INDEX; i++) {
        if (strcmp(val, profile_mode_names[i]) == 0) {
            aa_g_profile_mode = i;
            return 0;
        }
    }

    return -EINVAL;
}

/*
 * AppArmor init functions
 */

static int __init set_init_cxt(void)
{
    struct cred *cred = (struct cred *)current->real_cred;
    struct aa_task_cxt *cxt;

    cxt = aa_alloc_task_context(GFP_KERNEL);
    if (!cxt)
        return -ENOMEM;

    cxt->profile = aa_get_profile(root_ns->unconfined);
    cred->security = cxt;

    return 0;
}

static int __init apparmor_init(void)
{
    int error;

    if (!apparmor_enabled || !security_module_enable(&apparmor_ops)) {
        aa_info_message("AppArmor disabled by boot time parameter");
        apparmor_enabled = 0;
        return 0;
    }

    error = aa_alloc_root_ns();
    if (error) {
        AA_ERROR("Unable to allocate default profile namespace\n");
        goto alloc_out;
    }

    error = set_init_cxt();
    if (error) {
        AA_ERROR("Failed to set context on init task\n");
        goto register_security_out;
    }

    error = register_security(&apparmor_ops);
    if (error) {
        AA_ERROR("Unable to register AppArmor\n");
        goto set_init_cxt_out;
    }

    /* Report that AppArmor successfully initialized */
    apparmor_initialized = 1;
    if (aa_g_profile_mode == APPARMOR_COMPLAIN)
        aa_info_message("AppArmor initialized: complain mode enabled");
    else if (aa_g_profile_mode == APPARMOR_KILL)
        aa_info_message("AppArmor initialized: kill mode enabled");
    else
        aa_info_message("AppArmor initialized");

    return error;

set_init_cxt_out:
    aa_free_task_context(current->real_cred->security);

register_security_out:
    aa_free_root_ns();

alloc_out:
    aa_destroy_aafs();

    apparmor_enabled = 0;
    return error;
}

security_initcall(apparmor_init);