/*
 * 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/lsm_hooks.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 <linux/kmemleak.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/label.h"
#include "include/policy.h"
#include "include/policy_ns.h"
#include "include/procattr.h"
#include "include/mount.h"

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

DEFINE_PER_CPU(struct aa_buffers, aa_buffers);


/*
 * LSM hook functions
 */

/*
 * free the associated aa_task_ctx and put its labels
 */
static void apparmor_cred_free(struct cred *cred)
{
        aa_free_task_context(cred_ctx(cred));
        cred_ctx(cred) = 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_ctx *ctx = aa_alloc_task_context(gfp);

        if (!ctx)
                return -ENOMEM;

        cred_ctx(cred) = ctx;
        return 0;
}

/*
 * prepare new aa_task_ctx 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_ctx *ctx = aa_alloc_task_context(gfp);

        if (!ctx)
                return -ENOMEM;

        aa_dup_task_context(ctx, cred_ctx(old));
        cred_ctx(new) = ctx;
        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_ctx *old_ctx = cred_ctx(old);
        struct aa_task_ctx *new_ctx = cred_ctx(new);

        aa_dup_task_context(new_ctx, old_ctx);
}

static int apparmor_ptrace_access_check(struct task_struct *child,
                                        unsigned int mode)
{
        struct aa_label *tracer, *tracee;
        int error;

        tracer = begin_current_label_crit_section();
        tracee = aa_get_task_label(child);
        error = aa_may_ptrace(tracer, tracee,
                  mode == PTRACE_MODE_READ ? AA_PTRACE_READ : AA_PTRACE_TRACE);
        aa_put_label(tracee);
        end_current_label_crit_section(tracer);

        return error;
}

static int apparmor_ptrace_traceme(struct task_struct *parent)
{
        struct aa_label *tracer, *tracee;
        int error;

        tracee = begin_current_label_crit_section();
        tracer = aa_get_task_label(parent);
        error = aa_may_ptrace(tracer, tracee, AA_PTRACE_TRACE);
        aa_put_label(tracer);
        end_current_label_crit_section(tracee);

        return error;
}

/* 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_label *label;
        const struct cred *cred;

        rcu_read_lock();
        cred = __task_cred(target);
        label = aa_get_newest_cred_label(cred);

        /*
         * cap_capget is stacked ahead of this and will
         * initialize effective and permitted.
         */
        if (!unconfined(label)) {
                struct aa_profile *profile;
                struct label_it i;

                label_for_each_confined(i, label, profile) {
                        if (COMPLAIN_MODE(profile))
                                continue;
                        *effective = cap_intersect(*effective,
                                                   profile->caps.allow);
                        *permitted = cap_intersect(*permitted,
                                                   profile->caps.allow);
                }
        }
        rcu_read_unlock();
        aa_put_label(label);

        return 0;
}

static int apparmor_capable(const struct cred *cred, struct user_namespace *ns,
                            int cap, int audit)
{
        struct aa_label *label;
        int error = 0;

        label = aa_get_newest_cred_label(cred);
        if (!unconfined(label))
                error = aa_capable(label, cap, audit);
        aa_put_label(label);

        return error;
}

/**
 * common_perm - basic common permission check wrapper fn for paths
 * @op: operation being checked
 * @path: path to check permission of  (NOT NULL)
 * @mask: requested permissions mask
 * @cond: conditional info for the permission request  (NOT NULL)
 *
 * Returns: %0 else error code if error or permission denied
 */
static int common_perm(const char *op, const struct path *path, u32 mask,
                       struct path_cond *cond)
{
        struct aa_label *label;
        int error = 0;

        label = __begin_current_label_crit_section();
        if (!unconfined(label))
                error = aa_path_perm(op, label, path, 0, mask, cond);
        __end_current_label_crit_section(label);

        return error;
}

/**
 * common_perm_cond - common permission wrapper around inode cond
 * @op: operation being checked
 * @path: location to check (NOT NULL)
 * @mask: requested permissions mask
 *
 * Returns: %0 else error code if error or permission denied
 */
static int common_perm_cond(const char *op, const struct path *path, u32 mask)
{
        struct path_cond cond = { d_backing_inode(path->dentry)->i_uid,
                                  d_backing_inode(path->dentry)->i_mode
        };

        if (!path_mediated_fs(path->dentry))
                return 0;

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

/**
 * common_perm_dir_dentry - common permission wrapper when path is dir, dentry
 * @op: operation being checked
 * @dir: directory of the dentry  (NOT NULL)
 * @dentry: dentry to check  (NOT NULL)
 * @mask: requested permissions mask
 * @cond: conditional info for the permission request  (NOT NULL)
 *
 * Returns: %0 else error code if error or permission denied
 */
static int common_perm_dir_dentry(const char *op, const struct path *dir,
                                  struct dentry *dentry, u32 mask,
                                  struct path_cond *cond)
{
        struct path path = { .mnt = dir->mnt, .dentry = dentry };

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

/**
 * common_perm_rm - common permission wrapper for operations doing rm
 * @op: operation being checked
 * @dir: directory that the dentry is in  (NOT NULL)
 * @dentry: dentry being rm'd  (NOT NULL)
 * @mask: requested permission mask
 *
 * Returns: %0 else error code if error or permission denied
 */
static int common_perm_rm(const char *op, const struct path *dir,
                          struct dentry *dentry, u32 mask)
{
        struct inode *inode = d_backing_inode(dentry);
        struct path_cond cond = { };

        if (!inode || !path_mediated_fs(dentry))
                return 0;

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

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

/**
 * common_perm_create - common permission wrapper for operations doing create
 * @op: operation being checked
 * @dir: directory that dentry will be created in  (NOT NULL)
 * @dentry: dentry to create   (NOT NULL)
 * @mask: request permission mask
 * @mode: created file mode
 *
 * Returns: %0 else error code if error or permission denied
 */
static int common_perm_create(const char *op, const struct path *dir,
                              struct dentry *dentry, u32 mask, umode_t mode)
{
        struct path_cond cond = { current_fsuid(), mode };

        if (!path_mediated_fs(dir->dentry))
                return 0;

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

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

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

static int apparmor_path_mknod(const 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(const struct path *path)
{
        return common_perm_cond(OP_TRUNC, path, MAY_WRITE | AA_MAY_SETATTR);
}

static int apparmor_path_symlink(const 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, const struct path *new_dir,
                              struct dentry *new_dentry)
{
        struct aa_label *label;
        int error = 0;

        if (!path_mediated_fs(old_dentry))
                return 0;

        label = begin_current_label_crit_section();
        if (!unconfined(label))
                error = aa_path_link(label, old_dentry, new_dir, new_dentry);
        end_current_label_crit_section(label);

        return error;
}

static int apparmor_path_rename(const struct path *old_dir, struct dentry *old_dentry,
                                const struct path *new_dir, struct dentry *new_dentry)
{
        struct aa_label *label;
        int error = 0;

        if (!path_mediated_fs(old_dentry))
                return 0;

        label = begin_current_label_crit_section();
        if (!unconfined(label)) {
                struct path old_path = { .mnt = old_dir->mnt,
                                         .dentry = old_dentry };
                struct path new_path = { .mnt = new_dir->mnt,
                                         .dentry = new_dentry };
                struct path_cond cond = { d_backing_inode(old_dentry)->i_uid,
                                          d_backing_inode(old_dentry)->i_mode
                };

                error = aa_path_perm(OP_RENAME_SRC, label, &old_path, 0,
                                     MAY_READ | AA_MAY_GETATTR | MAY_WRITE |
                                     AA_MAY_SETATTR | AA_MAY_DELETE,
                                     &cond);
                if (!error)
                        error = aa_path_perm(OP_RENAME_DEST, label, &new_path,
                                             0, MAY_WRITE | AA_MAY_SETATTR |
                                             AA_MAY_CREATE, &cond);

        }
        end_current_label_crit_section(label);

        return error;
}

static int apparmor_path_chmod(const struct path *path, umode_t mode)
{
        return common_perm_cond(OP_CHMOD, path, AA_MAY_CHMOD);
}

static int apparmor_path_chown(const struct path *path, kuid_t uid, kgid_t gid)
{
        return common_perm_cond(OP_CHOWN, path, AA_MAY_CHOWN);
}

static int apparmor_inode_getattr(const struct path *path)
{
        return common_perm_cond(OP_GETATTR, path, AA_MAY_GETATTR);
}

static int apparmor_file_open(struct file *file, const struct cred *cred)
{
        struct aa_file_ctx *fctx = file_ctx(file);
        struct aa_label *label;
        int error = 0;

        if (!path_mediated_fs(file->f_path.dentry))
                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) {
                fctx->allow = MAY_EXEC | MAY_READ | AA_EXEC_MMAP;
                return 0;
        }

        label = aa_get_newest_cred_label(cred);
        if (!unconfined(label)) {
                struct inode *inode = file_inode(file);
                struct path_cond cond = { inode->i_uid, inode->i_mode };

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

        return error;
}

static int apparmor_file_alloc_security(struct file *file)
{
        int error = 0;

        /* freed by apparmor_file_free_security */
        struct aa_label *label = begin_current_label_crit_section();
        file->f_security = aa_alloc_file_ctx(label, GFP_KERNEL);
        if (!file_ctx(file))
                error = -ENOMEM;
        end_current_label_crit_section(label);

        return error;
}

static void apparmor_file_free_security(struct file *file)
{
        aa_free_file_ctx(file_ctx(file));
}

static int common_file_perm(const char *op, struct file *file, u32 mask)
{
        struct aa_label *label;
        int error = 0;

        /* don't reaudit files closed during inheritance */
        if (file->f_path.dentry == aa_null.dentry)
                return -EACCES;

        label = __begin_current_label_crit_section();
        error = aa_file_perm(op, label, file, mask);
        __end_current_label_crit_section(label);

        return error;
}

static int apparmor_file_receive(struct file *file)
{
        return common_file_perm(OP_FRECEIVE, file, aa_map_file_to_perms(file));
}

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(const char *op, struct file *file, unsigned long prot,
                       unsigned long flags)
{
        int mask = 0;

        if (!file || !file_ctx(file))
                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;

        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_sb_mount(const char *dev_name, const struct path *path,
                             const char *type, unsigned long flags, void *data)
{
        struct aa_label *label;
        int error = 0;

        /* Discard magic */
        if ((flags & MS_MGC_MSK) == MS_MGC_VAL)
                flags &= ~MS_MGC_MSK;

        flags &= ~AA_MS_IGNORE_MASK;

        label = __begin_current_label_crit_section();
        if (!unconfined(label)) {
                if (flags & MS_REMOUNT)
                        error = aa_remount(label, path, flags, data);
                else if (flags & MS_BIND)
                        error = aa_bind_mount(label, path, dev_name, flags);
                else if (flags & (MS_SHARED | MS_PRIVATE | MS_SLAVE |
                                  MS_UNBINDABLE))
                        error = aa_mount_change_type(label, path, flags);
                else if (flags & MS_MOVE)
                        error = aa_move_mount(label, path, dev_name);
                else
                        error = aa_new_mount(label, dev_name, path, type,
                                             flags, data);
        }
        __end_current_label_crit_section(label);

        return error;
}

static int apparmor_sb_umount(struct vfsmount *mnt, int flags)
{
        struct aa_label *label;
        int error = 0;

        label = __begin_current_label_crit_section();
        if (!unconfined(label))
                error = aa_umount(label, mnt, flags);
        __end_current_label_crit_section(label);

        return error;
}

static int apparmor_sb_pivotroot(const struct path *old_path,
                                 const struct path *new_path)
{
        struct aa_label *label;
        int error = 0;

        label = aa_get_current_label();
        if (!unconfined(label))
                error = aa_pivotroot(label, old_path, new_path);
        aa_put_label(label);

        return error;
}

static int apparmor_getprocattr(struct task_struct *task, char *name,
                                char **value)
{
        int error = -ENOENT;
        /* released below */
        const struct cred *cred = get_task_cred(task);
        struct aa_task_ctx *ctx = cred_ctx(cred);
        struct aa_label *label = NULL;

        if (strcmp(name, "current") == 0)
                label = aa_get_newest_label(ctx->label);
        else if (strcmp(name, "prev") == 0  && ctx->previous)
                label = aa_get_newest_label(ctx->previous);
        else if (strcmp(name, "exec") == 0 && ctx->onexec)
                label = aa_get_newest_label(ctx->onexec);
        else
                error = -EINVAL;

        if (label)
                error = aa_getprocattr(label, value);

        aa_put_label(label);
        put_cred(cred);

        return error;
}

static int apparmor_setprocattr(const char *name, void *value,
                                size_t size)
{
        char *command, *largs = NULL, *args = value;
        size_t arg_size;
        int error;
        DEFINE_AUDIT_DATA(sa, LSM_AUDIT_DATA_NONE, OP_SETPROCATTR);

        if (size == 0)
                return -EINVAL;

        /* AppArmor requires that the buffer must be null terminated atm */
        if (args[size - 1] != '\0') {
                /* null terminate */
                largs = args = kmalloc(size + 1, GFP_KERNEL);
                if (!args)
                        return -ENOMEM;
                memcpy(args, value, size);
                args[size] = '\0';
        }

        error = -EINVAL;
        args = strim(args);
        command = strsep(&args, " ");
        if (!args)
                goto out;
        args = skip_spaces(args);
        if (!*args)
                goto out;

        arg_size = size - (args - (largs ? largs : (char *) value));
        if (strcmp(name, "current") == 0) {
                if (strcmp(command, "changehat") == 0) {
                        error = aa_setprocattr_changehat(args, arg_size,
                                                         AA_CHANGE_NOFLAGS);
                } else if (strcmp(command, "permhat") == 0) {
                        error = aa_setprocattr_changehat(args, arg_size,
                                                         AA_CHANGE_TEST);
                } else if (strcmp(command, "changeprofile") == 0) {
                        error = aa_change_profile(args, AA_CHANGE_NOFLAGS);
                } else if (strcmp(command, "permprofile") == 0) {
                        error = aa_change_profile(args, AA_CHANGE_TEST);
                } else if (strcmp(command, "stack") == 0) {
                        error = aa_change_profile(args, AA_CHANGE_STACK);
                } else
                        goto fail;
        } else if (strcmp(name, "exec") == 0) {
                if (strcmp(command, "exec") == 0)
                        error = aa_change_profile(args, AA_CHANGE_ONEXEC);
                else if (strcmp(command, "stack") == 0)
                        error = aa_change_profile(args, (AA_CHANGE_ONEXEC |
                                                         AA_CHANGE_STACK));
                else
                        goto fail;
        } else
                /* only support the "current" and "exec" process attributes */
                goto fail;

        if (!error)
                error = size;
out:
        kfree(largs);
        return error;

fail:
        aad(&sa)->label = begin_current_label_crit_section();
        aad(&sa)->info = name;
        aad(&sa)->error = error = -EINVAL;
        aa_audit_msg(AUDIT_APPARMOR_DENIED, &sa, NULL);
        end_current_label_crit_section(aad(&sa)->label);
        goto out;
}

/**
 * apparmor_bprm_committing_creds - do task cleanup on committing new creds
 * @bprm: binprm for the exec  (NOT NULL)
 */
static void apparmor_bprm_committing_creds(struct linux_binprm *bprm)
{
        struct aa_label *label = aa_current_raw_label();
        struct aa_task_ctx *new_ctx = cred_ctx(bprm->cred);

        /* bail out if unconfined or not changing profile */
        if ((new_ctx->label->proxy == label->proxy) ||
            (unconfined(new_ctx->label)))
                return;

        aa_inherit_files(bprm->cred, current->files);

        current->pdeath_signal = 0;

        /* reset soft limits and set hard limits for the new label */
        __aa_transition_rlimits(label, new_ctx->label);
}

/**
 * apparmor_bprm_committed_cred - do cleanup after new creds committed
 * @bprm: binprm for the exec  (NOT NULL)
 */
static void apparmor_bprm_committed_creds(struct linux_binprm *bprm)
{
        /* TODO: cleanup signals - ipc mediation */
        return;
}

static int apparmor_task_setrlimit(struct task_struct *task,
                unsigned int resource, struct rlimit *new_rlim)
{
        struct aa_label *label = __begin_current_label_crit_section();
        int error = 0;

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

        return error;
}

static int apparmor_task_kill(struct task_struct *target, struct siginfo *info,
                              int sig, u32 secid)
{
        struct aa_label *cl, *tl;
        int error;

        if (secid)
                /* TODO: after secid to label mapping is done.
                 *  Dealing with USB IO specific behavior
                 */
                return 0;
        cl = __begin_current_label_crit_section();
        tl = aa_get_task_label(target);
        error = aa_may_signal(cl, tl, sig);
        aa_put_label(tl);
        __end_current_label_crit_section(cl);

        return error;
}

static struct security_hook_list apparmor_hooks[] __lsm_ro_after_init = {
        LSM_HOOK_INIT(ptrace_access_check, apparmor_ptrace_access_check),
        LSM_HOOK_INIT(ptrace_traceme, apparmor_ptrace_traceme),
        LSM_HOOK_INIT(capget, apparmor_capget),
        LSM_HOOK_INIT(capable, apparmor_capable),

        LSM_HOOK_INIT(sb_mount, apparmor_sb_mount),
        LSM_HOOK_INIT(sb_umount, apparmor_sb_umount),
        LSM_HOOK_INIT(sb_pivotroot, apparmor_sb_pivotroot),

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

        LSM_HOOK_INIT(file_open, apparmor_file_open),
        LSM_HOOK_INIT(file_receive, apparmor_file_receive),
        LSM_HOOK_INIT(file_permission, apparmor_file_permission),
        LSM_HOOK_INIT(file_alloc_security, apparmor_file_alloc_security),
        LSM_HOOK_INIT(file_free_security, apparmor_file_free_security),
        LSM_HOOK_INIT(mmap_file, apparmor_mmap_file),
        LSM_HOOK_INIT(file_mprotect, apparmor_file_mprotect),
        LSM_HOOK_INIT(file_lock, apparmor_file_lock),

        LSM_HOOK_INIT(getprocattr, apparmor_getprocattr),
        LSM_HOOK_INIT(setprocattr, apparmor_setprocattr),

        LSM_HOOK_INIT(cred_alloc_blank, apparmor_cred_alloc_blank),
        LSM_HOOK_INIT(cred_free, apparmor_cred_free),
        LSM_HOOK_INIT(cred_prepare, apparmor_cred_prepare),
        LSM_HOOK_INIT(cred_transfer, apparmor_cred_transfer),

        LSM_HOOK_INIT(bprm_set_creds, apparmor_bprm_set_creds),
        LSM_HOOK_INIT(bprm_committing_creds, apparmor_bprm_committing_creds),
        LSM_HOOK_INIT(bprm_committed_creds, apparmor_bprm_committed_creds),

        LSM_HOOK_INIT(task_setrlimit, apparmor_task_setrlimit),
        LSM_HOOK_INIT(task_kill, apparmor_task_kill),
};

/*
 * 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 const struct kernel_param_ops param_ops_aabool = {
        .flags = KERNEL_PARAM_OPS_FL_NOARG,
        .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 const 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 const struct kernel_param_ops param_ops_aalockpolicy = {
        .flags = KERNEL_PARAM_OPS_FL_NOARG,
        .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);

/* whether policy verification hashing is enabled */
bool aa_g_hash_policy = IS_ENABLED(CONFIG_SECURITY_APPARMOR_HASH_DEFAULT);
#ifdef CONFIG_SECURITY_APPARMOR_HASH
module_param_named(hash_policy, aa_g_hash_policy, aabool, S_IRUSR | S_IWUSR);
#endif

/* Debug mode */
bool aa_g_debug = IS_ENABLED(CONFIG_SECURITY_APPARMOR_DEBUG_MESSAGES);
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);

/* Determines how paranoid loading of policy is and how much verification
 * on the loaded policy is done.
 * DEPRECATED: read only as strict checking of load is always done now
 * that none root users (user namespaces) can load policy.
 */
bool aa_g_paranoid_load = 1;
module_param_named(paranoid_load, aa_g_paranoid_load, aabool, S_IRUGO);

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

static int __init apparmor_enabled_setup(char *str)
{
        unsigned long enabled;
        int error = kstrtoul(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 (!apparmor_enabled)
                return -EINVAL;
        if (apparmor_initialized && !policy_admin_capable(NULL))
                return -EPERM;
        return param_set_bool(val, kp);
}

static int param_get_aalockpolicy(char *buffer, const struct kernel_param *kp)
{
        if (!apparmor_enabled)
                return -EINVAL;
        if (apparmor_initialized && !policy_view_capable(NULL))
                return -EPERM;
        return param_get_bool(buffer, kp);
}

static int param_set_aabool(const char *val, const struct kernel_param *kp)
{
        if (!apparmor_enabled)
                return -EINVAL;
        if (apparmor_initialized && !policy_admin_capable(NULL))
                return -EPERM;
        return param_set_bool(val, kp);
}

static int param_get_aabool(char *buffer, const struct kernel_param *kp)
{
        if (!apparmor_enabled)
                return -EINVAL;
        if (apparmor_initialized && !policy_view_capable(NULL))
                return -EPERM;
        return param_get_bool(buffer, kp);
}

static int param_set_aauint(const char *val, const struct kernel_param *kp)
{
        int error;

        if (!apparmor_enabled)
                return -EINVAL;
        /* file is ro but enforce 2nd line check */
        if (apparmor_initialized)
                return -EPERM;

        error = param_set_uint(val, kp);
        pr_info("AppArmor: buffer size set to %d bytes\n", aa_g_path_max);

        return error;
}

static int param_get_aauint(char *buffer, const struct kernel_param *kp)
{
        if (!apparmor_enabled)
                return -EINVAL;
        if (apparmor_initialized && !policy_view_capable(NULL))
                return -EPERM;
        return param_get_uint(buffer, kp);
}

static int param_get_audit(char *buffer, struct kernel_param *kp)
{
        if (!apparmor_enabled)
                return -EINVAL;
        if (apparmor_initialized && !policy_view_capable(NULL))
                return -EPERM;
        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 (!apparmor_enabled)
                return -EINVAL;
        if (!val)
                return -EINVAL;
        if (apparmor_initialized && !policy_admin_capable(NULL))
                return -EPERM;

        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 (!apparmor_enabled)
                return -EINVAL;
        if (apparmor_initialized && !policy_view_capable(NULL))
                return -EPERM;

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

static int param_set_mode(const char *val, struct kernel_param *kp)
{
        int i;

        if (!apparmor_enabled)
                return -EINVAL;
        if (!val)

                return -EINVAL;
        if (apparmor_initialized && !policy_admin_capable(NULL))
                return -EPERM;

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

        return -EINVAL;
}

/*
 * AppArmor init functions
 */

/**
 * set_init_ctx - set a task context and profile on the first task.
 *
 * TODO: allow setting an alternate profile than unconfined
 */
static int __init set_init_ctx(void)
{
        struct cred *cred = (struct cred *)current->real_cred;
        struct aa_task_ctx *ctx;

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

        ctx->label = aa_get_label(ns_unconfined(root_ns));
        cred_ctx(cred) = ctx;

        return 0;
}

static void destroy_buffers(void)
{
        u32 i, j;

        for_each_possible_cpu(i) {
                for_each_cpu_buffer(j) {
                        kfree(per_cpu(aa_buffers, i).buf[j]);
                        per_cpu(aa_buffers, i).buf[j] = NULL;
                }
        }
}

static int __init alloc_buffers(void)
{
        u32 i, j;

        for_each_possible_cpu(i) {
                for_each_cpu_buffer(j) {
                        char *buffer;

                        if (cpu_to_node(i) > num_online_nodes())
                                /* fallback to kmalloc for offline nodes */
                                buffer = kmalloc(aa_g_path_max, GFP_KERNEL);
                        else
                                buffer = kmalloc_node(aa_g_path_max, GFP_KERNEL,
                                                      cpu_to_node(i));
                        if (!buffer) {
                                destroy_buffers();
                                return -ENOMEM;
                        }
                        per_cpu(aa_buffers, i).buf[j] = buffer;
                }
        }

        return 0;
}

#ifdef CONFIG_SYSCTL
static int apparmor_dointvec(struct ctl_table *table, int write,
                             void __user *buffer, size_t *lenp, loff_t *ppos)
{
        if (!policy_admin_capable(NULL))
                return -EPERM;
        if (!apparmor_enabled)
                return -EINVAL;

        return proc_dointvec(table, write, buffer, lenp, ppos);
}

static struct ctl_path apparmor_sysctl_path[] = {
        { .procname = "kernel", },
        { }
};

static struct ctl_table apparmor_sysctl_table[] = {
        {
                .procname       = "unprivileged_userns_apparmor_policy",
                .data           = &unprivileged_userns_apparmor_policy,
                .maxlen         = sizeof(int),
                .mode           = 0600,
                .proc_handler   = apparmor_dointvec,
        },
        { }
};

static int __init apparmor_init_sysctl(void)
{
        return register_sysctl_paths(apparmor_sysctl_path,
                                     apparmor_sysctl_table) ? 0 : -ENOMEM;
}
#else
static inline int apparmor_init_sysctl(void)
{
        return 0;
}
#endif /* CONFIG_SYSCTL */

static int __init apparmor_init(void)
{
        int error;

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

        error = aa_setup_dfa_engine();
        if (error) {
                AA_ERROR("Unable to setup dfa engine\n");
                goto alloc_out;
        }

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

        error = apparmor_init_sysctl();
        if (error) {
                AA_ERROR("Unable to register sysctls\n");
                goto alloc_out;

        }

        error = alloc_buffers();
        if (error) {
                AA_ERROR("Unable to allocate work buffers\n");
                goto buffers_out;
        }

        error = set_init_ctx();
        if (error) {
                AA_ERROR("Failed to set context on init task\n");
                aa_free_root_ns();
                goto buffers_out;
        }
        security_add_hooks(apparmor_hooks, ARRAY_SIZE(apparmor_hooks),
                                "apparmor");

        /* 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;

buffers_out:
        destroy_buffers();

alloc_out:
        aa_destroy_aafs();
        aa_teardown_dfa_engine();

        apparmor_enabled = 0;
        return error;
}

security_initcall(apparmor_init);