// SPDX-License-Identifier: GPL-2.0-only
/*
 * AppArmor security module
 *
 * This file contains AppArmor LSM hooks.
 *
 * Copyright (C) 1998-2008 Novell/SUSE
 * Copyright 2009-2010 Canonical Ltd.
 */

#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/netfilter_ipv4.h>
#include <linux/netfilter_ipv6.h>
#include <linux/zlib.h>
#include <net/sock.h>
#include <uapi/linux/mount.h>

#include "include/apparmor.h"
#include "include/apparmorfs.h"
#include "include/audit.h"
#include "include/capability.h"
#include "include/cred.h"
#include "include/file.h"
#include "include/ipc.h"
#include "include/net.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"
#include "include/secid.h"

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

union aa_buffer {
        struct list_head list;
        char buffer[1];
};

#define RESERVE_COUNT 2
static int reserve_count = RESERVE_COUNT;
static int buffer_count;

static LIST_HEAD(aa_global_buffers);
static DEFINE_SPINLOCK(aa_buffers_lock);

/*
 * LSM hook functions
 */

/*
 * put the associated labels
 */
static void apparmor_cred_free(struct cred *cred)
{
        aa_put_label(cred_label(cred));
        set_cred_label(cred, NULL);
}

/*
 * allocate the apparmor part of blank credentials
 */
static int apparmor_cred_alloc_blank(struct cred *cred, gfp_t gfp)
{
        set_cred_label(cred, NULL);
        return 0;
}

/*
 * prepare new cred label for modification by prepare_cred block
 */
static int apparmor_cred_prepare(struct cred *new, const struct cred *old,
                                 gfp_t gfp)
{
        set_cred_label(new, aa_get_newest_label(cred_label(old)));
        return 0;
}

/*
 * transfer the apparmor data to a blank set of creds
 */
static void apparmor_cred_transfer(struct cred *new, const struct cred *old)
{
        set_cred_label(new, aa_get_newest_label(cred_label(old)));
}

static void apparmor_task_free(struct task_struct *task)
{

        aa_free_task_ctx(task_ctx(task));
}

static int apparmor_task_alloc(struct task_struct *task,
                               unsigned long clone_flags)
{
        struct aa_task_ctx *new = task_ctx(task);

        aa_dup_task_ctx(new, task_ctx(current));

        return 0;
}

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, unsigned int opts)
{
        struct aa_label *label;
        int error = 0;

        label = aa_get_newest_cred_label(cred);
        if (!unconfined(label))
                error = aa_capable(label, cap, opts);
        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)
{
        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(file->f_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)
{
        struct aa_file_ctx *ctx = file_ctx(file);
        struct aa_label *label = begin_current_label_crit_section();

        spin_lock_init(&ctx->lock);
        rcu_assign_pointer(ctx->label, aa_get_label(label));
        end_current_label_crit_section(label);
        return 0;
}

static void apparmor_file_free_security(struct file *file)
{
        struct aa_file_ctx *ctx = file_ctx(file);

        if (ctx)
                aa_put_label(rcu_access_pointer(ctx->label));
}

static int common_file_perm(const char *op, struct file *file, u32 mask,
                            bool in_atomic)
{
        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, in_atomic);
        __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),
                                false);
}

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

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, false);
}

static int common_mmap(const char *op, struct file *file, unsigned long prot,
                       unsigned long flags, bool in_atomic)
{
        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, in_atomic);
}

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, GFP_ATOMIC);
}

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,
                           false);
}

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 = task_ctx(current);
        struct aa_label *label = NULL;

        if (strcmp(name, "current") == 0)
                label = aa_get_newest_label(cred_label(cred));
        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_label *new_label = cred_label(bprm->cred);

        /* bail out if unconfined or not changing profile */
        if ((new_label->proxy == label->proxy) ||
            (unconfined(new_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_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)
{
        /* clear out temporary/transitional state from the context */
        aa_clear_task_ctx_trans(task_ctx(current));

        return;
}

static void apparmor_task_getsecid(struct task_struct *p, u32 *secid)
{
        struct aa_label *label = aa_get_task_label(p);
        *secid = label->secid;
        aa_put_label(label);
}

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 kernel_siginfo *info,
                              int sig, const struct cred *cred)
{
        struct aa_label *cl, *tl;
        int error;

        if (cred) {
                /*
                 * Dealing with USB IO specific behavior
                 */
                cl = aa_get_newest_cred_label(cred);
                tl = aa_get_task_label(target);
                error = aa_may_signal(cl, tl, sig);
                aa_put_label(cl);
                aa_put_label(tl);
                return error;
        }

        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;
}

/**
 * apparmor_sk_alloc_security - allocate and attach the sk_security field
 */
static int apparmor_sk_alloc_security(struct sock *sk, int family, gfp_t flags)
{
        struct aa_sk_ctx *ctx;

        ctx = kzalloc(sizeof(*ctx), flags);
        if (!ctx)
                return -ENOMEM;

        SK_CTX(sk) = ctx;

        return 0;
}

/**
 * apparmor_sk_free_security - free the sk_security field
 */
static void apparmor_sk_free_security(struct sock *sk)
{
        struct aa_sk_ctx *ctx = SK_CTX(sk);

        SK_CTX(sk) = NULL;
        aa_put_label(ctx->label);
        aa_put_label(ctx->peer);
        kfree(ctx);
}

/**
 * apparmor_clone_security - clone the sk_security field
 */
static void apparmor_sk_clone_security(const struct sock *sk,
                                       struct sock *newsk)
{
        struct aa_sk_ctx *ctx = SK_CTX(sk);
        struct aa_sk_ctx *new = SK_CTX(newsk);

        new->label = aa_get_label(ctx->label);
        new->peer = aa_get_label(ctx->peer);
}

/**
 * apparmor_socket_create - check perms before creating a new socket
 */
static int apparmor_socket_create(int family, int type, int protocol, int kern)
{
        struct aa_label *label;
        int error = 0;

        AA_BUG(in_interrupt());

        label = begin_current_label_crit_section();
        if (!(kern || unconfined(label)))
                error = af_select(family,
                                  create_perm(label, family, type, protocol),
                                  aa_af_perm(label, OP_CREATE, AA_MAY_CREATE,
                                             family, type, protocol));
        end_current_label_crit_section(label);

        return error;
}

/**
 * apparmor_socket_post_create - setup the per-socket security struct
 *
 * Note:
 * -   kernel sockets currently labeled unconfined but we may want to
 *     move to a special kernel label
 * -   socket may not have sk here if created with sock_create_lite or
 *     sock_alloc. These should be accept cases which will be handled in
 *     sock_graft.
 */
static int apparmor_socket_post_create(struct socket *sock, int family,
                                       int type, int protocol, int kern)
{
        struct aa_label *label;

        if (kern) {
                struct aa_ns *ns = aa_get_current_ns();

                label = aa_get_label(ns_unconfined(ns));
                aa_put_ns(ns);
        } else
                label = aa_get_current_label();

        if (sock->sk) {
                struct aa_sk_ctx *ctx = SK_CTX(sock->sk);

                aa_put_label(ctx->label);
                ctx->label = aa_get_label(label);
        }
        aa_put_label(label);

        return 0;
}

/**
 * apparmor_socket_bind - check perms before bind addr to socket
 */
static int apparmor_socket_bind(struct socket *sock,
                                struct sockaddr *address, int addrlen)
{
        AA_BUG(!sock);
        AA_BUG(!sock->sk);
        AA_BUG(!address);
        AA_BUG(in_interrupt());

        return af_select(sock->sk->sk_family,
                         bind_perm(sock, address, addrlen),
                         aa_sk_perm(OP_BIND, AA_MAY_BIND, sock->sk));
}

/**
 * apparmor_socket_connect - check perms before connecting @sock to @address
 */
static int apparmor_socket_connect(struct socket *sock,
                                   struct sockaddr *address, int addrlen)
{
        AA_BUG(!sock);
        AA_BUG(!sock->sk);
        AA_BUG(!address);
        AA_BUG(in_interrupt());

        return af_select(sock->sk->sk_family,
                         connect_perm(sock, address, addrlen),
                         aa_sk_perm(OP_CONNECT, AA_MAY_CONNECT, sock->sk));
}

/**
 * apparmor_socket_list - check perms before allowing listen
 */
static int apparmor_socket_listen(struct socket *sock, int backlog)
{
        AA_BUG(!sock);
        AA_BUG(!sock->sk);
        AA_BUG(in_interrupt());

        return af_select(sock->sk->sk_family,
                         listen_perm(sock, backlog),
                         aa_sk_perm(OP_LISTEN, AA_MAY_LISTEN, sock->sk));
}

/**
 * apparmor_socket_accept - check perms before accepting a new connection.
 *
 * Note: while @newsock is created and has some information, the accept
 *       has not been done.
 */
static int apparmor_socket_accept(struct socket *sock, struct socket *newsock)
{
        AA_BUG(!sock);
        AA_BUG(!sock->sk);
        AA_BUG(!newsock);
        AA_BUG(in_interrupt());

        return af_select(sock->sk->sk_family,
                         accept_perm(sock, newsock),
                         aa_sk_perm(OP_ACCEPT, AA_MAY_ACCEPT, sock->sk));
}

static int aa_sock_msg_perm(const char *op, u32 request, struct socket *sock,
                            struct msghdr *msg, int size)
{
        AA_BUG(!sock);
        AA_BUG(!sock->sk);
        AA_BUG(!msg);
        AA_BUG(in_interrupt());

        return af_select(sock->sk->sk_family,
                         msg_perm(op, request, sock, msg, size),
                         aa_sk_perm(op, request, sock->sk));
}

/**
 * apparmor_socket_sendmsg - check perms before sending msg to another socket
 */
static int apparmor_socket_sendmsg(struct socket *sock,
                                   struct msghdr *msg, int size)
{
        return aa_sock_msg_perm(OP_SENDMSG, AA_MAY_SEND, sock, msg, size);
}

/**
 * apparmor_socket_recvmsg - check perms before receiving a message
 */
static int apparmor_socket_recvmsg(struct socket *sock,
                                   struct msghdr *msg, int size, int flags)
{
        return aa_sock_msg_perm(OP_RECVMSG, AA_MAY_RECEIVE, sock, msg, size);
}

/* revaliation, get/set attr, shutdown */
static int aa_sock_perm(const char *op, u32 request, struct socket *sock)
{
        AA_BUG(!sock);
        AA_BUG(!sock->sk);
        AA_BUG(in_interrupt());

        return af_select(sock->sk->sk_family,
                         sock_perm(op, request, sock),
                         aa_sk_perm(op, request, sock->sk));
}

/**
 * apparmor_socket_getsockname - check perms before getting the local address
 */
static int apparmor_socket_getsockname(struct socket *sock)
{
        return aa_sock_perm(OP_GETSOCKNAME, AA_MAY_GETATTR, sock);
}

/**
 * apparmor_socket_getpeername - check perms before getting remote address
 */
static int apparmor_socket_getpeername(struct socket *sock)
{
        return aa_sock_perm(OP_GETPEERNAME, AA_MAY_GETATTR, sock);
}

/* revaliation, get/set attr, opt */
static int aa_sock_opt_perm(const char *op, u32 request, struct socket *sock,
                            int level, int optname)
{
        AA_BUG(!sock);
        AA_BUG(!sock->sk);
        AA_BUG(in_interrupt());

        return af_select(sock->sk->sk_family,
                         opt_perm(op, request, sock, level, optname),
                         aa_sk_perm(op, request, sock->sk));
}

/**
 * apparmor_getsockopt - check perms before getting socket options
 */
static int apparmor_socket_getsockopt(struct socket *sock, int level,
                                      int optname)
{
        return aa_sock_opt_perm(OP_GETSOCKOPT, AA_MAY_GETOPT, sock,
                                level, optname);
}

/**
 * apparmor_setsockopt - check perms before setting socket options
 */
static int apparmor_socket_setsockopt(struct socket *sock, int level,
                                      int optname)
{
        return aa_sock_opt_perm(OP_SETSOCKOPT, AA_MAY_SETOPT, sock,
                                level, optname);
}

/**
 * apparmor_socket_shutdown - check perms before shutting down @sock conn
 */
static int apparmor_socket_shutdown(struct socket *sock, int how)
{
        return aa_sock_perm(OP_SHUTDOWN, AA_MAY_SHUTDOWN, sock);
}

#ifdef CONFIG_NETWORK_SECMARK
/**
 * apparmor_socket_sock_recv_skb - check perms before associating skb to sk
 *
 * Note: can not sleep may be called with locks held
 *
 * dont want protocol specific in __skb_recv_datagram()
 * to deny an incoming connection  socket_sock_rcv_skb()
 */
static int apparmor_socket_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)
{
        struct aa_sk_ctx *ctx = SK_CTX(sk);

        if (!skb->secmark)
                return 0;

        return apparmor_secmark_check(ctx->label, OP_RECVMSG, AA_MAY_RECEIVE,
                                      skb->secmark, sk);
}
#endif


static struct aa_label *sk_peer_label(struct sock *sk)
{
        struct aa_sk_ctx *ctx = SK_CTX(sk);

        if (ctx->peer)
                return ctx->peer;

        return ERR_PTR(-ENOPROTOOPT);
}

/**
 * apparmor_socket_getpeersec_stream - get security context of peer
 *
 * Note: for tcp only valid if using ipsec or cipso on lan
 */
static int apparmor_socket_getpeersec_stream(struct socket *sock,
                                             char __user *optval,
                                             int __user *optlen,
                                             unsigned int len)
{
        char *name;
        int slen, error = 0;
        struct aa_label *label;
        struct aa_label *peer;

        label = begin_current_label_crit_section();
        peer = sk_peer_label(sock->sk);
        if (IS_ERR(peer)) {
                error = PTR_ERR(peer);
                goto done;
        }
        slen = aa_label_asxprint(&name, labels_ns(label), peer,
                                 FLAG_SHOW_MODE | FLAG_VIEW_SUBNS |
                                 FLAG_HIDDEN_UNCONFINED, GFP_KERNEL);
        /* don't include terminating \0 in slen, it breaks some apps */
        if (slen < 0) {
                error = -ENOMEM;
        } else {
                if (slen > len) {
                        error = -ERANGE;
                } else if (copy_to_user(optval, name, slen)) {
                        error = -EFAULT;
                        goto out;
                }
                if (put_user(slen, optlen))
                        error = -EFAULT;
out:
                kfree(name);

        }

done:
        end_current_label_crit_section(label);

        return error;
}

/**
 * apparmor_socket_getpeersec_dgram - get security label of packet
 * @sock: the peer socket
 * @skb: packet data
 * @secid: pointer to where to put the secid of the packet
 *
 * Sets the netlabel socket state on sk from parent
 */
static int apparmor_socket_getpeersec_dgram(struct socket *sock,
                                            struct sk_buff *skb, u32 *secid)

{
        /* TODO: requires secid support */
        return -ENOPROTOOPT;
}

/**
 * apparmor_sock_graft - Initialize newly created socket
 * @sk: child sock
 * @parent: parent socket
 *
 * Note: could set off of SOCK_CTX(parent) but need to track inode and we can
 *       just set sk security information off of current creating process label
 *       Labeling of sk for accept case - probably should be sock based
 *       instead of task, because of the case where an implicitly labeled
 *       socket is shared by different tasks.
 */
static void apparmor_sock_graft(struct sock *sk, struct socket *parent)
{
        struct aa_sk_ctx *ctx = SK_CTX(sk);

        if (!ctx->label)
                ctx->label = aa_get_current_label();
}

#ifdef CONFIG_NETWORK_SECMARK
static int apparmor_inet_conn_request(struct sock *sk, struct sk_buff *skb,
                                      struct request_sock *req)
{
        struct aa_sk_ctx *ctx = SK_CTX(sk);

        if (!skb->secmark)
                return 0;

        return apparmor_secmark_check(ctx->label, OP_CONNECT, AA_MAY_CONNECT,
                                      skb->secmark, sk);
}
#endif

/*
 * The cred blob is a pointer to, not an instance of, an aa_task_ctx.
 */
struct lsm_blob_sizes apparmor_blob_sizes __lsm_ro_after_init = {
        .lbs_cred = sizeof(struct aa_task_ctx *),
        .lbs_file = sizeof(struct aa_file_ctx),
        .lbs_task = sizeof(struct aa_task_ctx),
};

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(sk_alloc_security, apparmor_sk_alloc_security),
        LSM_HOOK_INIT(sk_free_security, apparmor_sk_free_security),
        LSM_HOOK_INIT(sk_clone_security, apparmor_sk_clone_security),

        LSM_HOOK_INIT(socket_create, apparmor_socket_create),
        LSM_HOOK_INIT(socket_post_create, apparmor_socket_post_create),
        LSM_HOOK_INIT(socket_bind, apparmor_socket_bind),
        LSM_HOOK_INIT(socket_connect, apparmor_socket_connect),
        LSM_HOOK_INIT(socket_listen, apparmor_socket_listen),
        LSM_HOOK_INIT(socket_accept, apparmor_socket_accept),
        LSM_HOOK_INIT(socket_sendmsg, apparmor_socket_sendmsg),
        LSM_HOOK_INIT(socket_recvmsg, apparmor_socket_recvmsg),
        LSM_HOOK_INIT(socket_getsockname, apparmor_socket_getsockname),
        LSM_HOOK_INIT(socket_getpeername, apparmor_socket_getpeername),
        LSM_HOOK_INIT(socket_getsockopt, apparmor_socket_getsockopt),
        LSM_HOOK_INIT(socket_setsockopt, apparmor_socket_setsockopt),
        LSM_HOOK_INIT(socket_shutdown, apparmor_socket_shutdown),
#ifdef CONFIG_NETWORK_SECMARK
        LSM_HOOK_INIT(socket_sock_rcv_skb, apparmor_socket_sock_rcv_skb),
#endif
        LSM_HOOK_INIT(socket_getpeersec_stream,
                      apparmor_socket_getpeersec_stream),
        LSM_HOOK_INIT(socket_getpeersec_dgram,
                      apparmor_socket_getpeersec_dgram),
        LSM_HOOK_INIT(sock_graft, apparmor_sock_graft),
#ifdef CONFIG_NETWORK_SECMARK
        LSM_HOOK_INIT(inet_conn_request, apparmor_inet_conn_request),
#endif

        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_free, apparmor_task_free),
        LSM_HOOK_INIT(task_alloc, apparmor_task_alloc),
        LSM_HOOK_INIT(task_getsecid, apparmor_task_getsecid),
        LSM_HOOK_INIT(task_setrlimit, apparmor_task_setrlimit),
        LSM_HOOK_INIT(task_kill, apparmor_task_kill),

#ifdef CONFIG_AUDIT
        LSM_HOOK_INIT(audit_rule_init, aa_audit_rule_init),
        LSM_HOOK_INIT(audit_rule_known, aa_audit_rule_known),
        LSM_HOOK_INIT(audit_rule_match, aa_audit_rule_match),
        LSM_HOOK_INIT(audit_rule_free, aa_audit_rule_free),
#endif

        LSM_HOOK_INIT(secid_to_secctx, apparmor_secid_to_secctx),
        LSM_HOOK_INIT(secctx_to_secid, apparmor_secctx_to_secid),
        LSM_HOOK_INIT(release_secctx, apparmor_release_secctx),
};

/*
 * 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_aacompressionlevel(const char *val,
                                        const struct kernel_param *kp);
static int param_get_aacompressionlevel(char *buffer,
                                        const struct kernel_param *kp);
#define param_check_aacompressionlevel param_check_int
static const struct kernel_param_ops param_ops_aacompressionlevel = {
        .set = param_set_aacompressionlevel,
        .get = param_get_aacompressionlevel
};

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

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

/* policy loaddata compression level */
int aa_g_rawdata_compression_level = Z_DEFAULT_COMPRESSION;
module_param_named(rawdata_compression_level, aa_g_rawdata_compression_level,
                   aacompressionlevel, 0400);

/* 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 = true;
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 = true;
module_param_named(paranoid_load, aa_g_paranoid_load, aabool, S_IRUGO);

static int param_get_aaintbool(char *buffer, const struct kernel_param *kp);
static int param_set_aaintbool(const char *val, const struct kernel_param *kp);
#define param_check_aaintbool param_check_int
static const struct kernel_param_ops param_ops_aaintbool = {
        .set = param_set_aaintbool,
        .get = param_get_aaintbool
};
/* Boot time disable flag */
static int apparmor_enabled __lsm_ro_after_init = 1;
module_param_named(enabled, apparmor_enabled, aaintbool, 0444);

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);
        aa_g_path_max = max_t(uint32_t, aa_g_path_max, sizeof(union aa_buffer));
        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);
}

/* Can only be set before AppArmor is initialized (i.e. on boot cmdline). */
static int param_set_aaintbool(const char *val, const struct kernel_param *kp)
{
        struct kernel_param kp_local;
        bool value;
        int error;

        if (apparmor_initialized)
                return -EPERM;

        /* Create local copy, with arg pointing to bool type. */
        value = !!*((int *)kp->arg);
        memcpy(&kp_local, kp, sizeof(kp_local));
        kp_local.arg = &value;

        error = param_set_bool(val, &kp_local);
        if (!error)
                *((int *)kp->arg) = *((bool *)kp_local.arg);
        return error;
}

/*
 * To avoid changing /sys/module/apparmor/parameters/enabled from Y/N to
 * 1/0, this converts the "int that is actually bool" back to bool for
 * display in the /sys filesystem, while keeping it "int" for the LSM
 * infrastructure.
 */
static int param_get_aaintbool(char *buffer, const struct kernel_param *kp)
{
        struct kernel_param kp_local;
        bool value;

        /* Create local copy, with arg pointing to bool type. */
        value = !!*((int *)kp->arg);
        memcpy(&kp_local, kp, sizeof(kp_local));
        kp_local.arg = &value;

        return param_get_bool(buffer, &kp_local);
}

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

        if (!apparmor_enabled)
                return -EINVAL;
        if (apparmor_initialized)
                return -EPERM;

        error = param_set_int(val, kp);

        aa_g_rawdata_compression_level = clamp(aa_g_rawdata_compression_level,
                                               Z_NO_COMPRESSION,
                                               Z_BEST_COMPRESSION);
        pr_info("AppArmor: policy rawdata compression level set to %u\n",
                aa_g_rawdata_compression_level);

        return error;
}

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

static int param_get_audit(char *buffer, const 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, const struct kernel_param *kp)
{
        int i;

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

        i = match_string(audit_mode_names, AUDIT_MAX_INDEX, val);
        if (i < 0)
                return -EINVAL;

        aa_g_audit = i;
        return 0;
}

static int param_get_mode(char *buffer, const 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, const struct kernel_param *kp)
{
        int i;

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

        i = match_string(aa_profile_mode_names, APPARMOR_MODE_NAMES_MAX_INDEX,
                         val);
        if (i < 0)
                return -EINVAL;

        aa_g_profile_mode = i;
        return 0;
}

char *aa_get_buffer(bool in_atomic)
{
        union aa_buffer *aa_buf;
        bool try_again = true;
        gfp_t flags = (GFP_KERNEL | __GFP_RETRY_MAYFAIL | __GFP_NOWARN);

retry:
        spin_lock(&aa_buffers_lock);
        if (buffer_count > reserve_count ||
            (in_atomic && !list_empty(&aa_global_buffers))) {
                aa_buf = list_first_entry(&aa_global_buffers, union aa_buffer,
                                          list);
                list_del(&aa_buf->list);
                buffer_count--;
                spin_unlock(&aa_buffers_lock);
                return &aa_buf->buffer[0];
        }
        if (in_atomic) {
                /*
                 * out of reserve buffers and in atomic context so increase
                 * how many buffers to keep in reserve
                 */
                reserve_count++;
                flags = GFP_ATOMIC;
        }
        spin_unlock(&aa_buffers_lock);

        if (!in_atomic)
                might_sleep();
        aa_buf = kmalloc(aa_g_path_max, flags);
        if (!aa_buf) {
                if (try_again) {
                        try_again = false;
                        goto retry;
                }
                pr_warn_once("AppArmor: Failed to allocate a memory buffer.\n");
                return NULL;
        }
        return &aa_buf->buffer[0];
}

void aa_put_buffer(char *buf)
{
        union aa_buffer *aa_buf;

        if (!buf)
                return;
        aa_buf = container_of(buf, union aa_buffer, buffer[0]);

        spin_lock(&aa_buffers_lock);
        list_add(&aa_buf->list, &aa_global_buffers);
        buffer_count++;
        spin_unlock(&aa_buffers_lock);
}

/*
 * 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 = (__force struct cred *)current->real_cred;

        set_cred_label(cred, aa_get_label(ns_unconfined(root_ns)));

        return 0;
}

static void destroy_buffers(void)
{
        union aa_buffer *aa_buf;

        spin_lock(&aa_buffers_lock);
        while (!list_empty(&aa_global_buffers)) {
                aa_buf = list_first_entry(&aa_global_buffers, union aa_buffer,
                                         list);
                list_del(&aa_buf->list);
                spin_unlock(&aa_buffers_lock);
                kfree(aa_buf);
                spin_lock(&aa_buffers_lock);
        }
        spin_unlock(&aa_buffers_lock);
}

static int __init alloc_buffers(void)
{
        union aa_buffer *aa_buf;
        int i, num;

        /*
         * A function may require two buffers at once. Usually the buffers are
         * used for a short period of time and are shared. On UP kernel buffers
         * two should be enough, with more CPUs it is possible that more
         * buffers will be used simultaneously. The preallocated pool may grow.
         * This preallocation has also the side-effect that AppArmor will be
         * disabled early at boot if aa_g_path_max is extremly high.
         */
        if (num_online_cpus() > 1)
                num = 4 + RESERVE_COUNT;
        else
                num = 2 + RESERVE_COUNT;

        for (i = 0; i < num; i++) {

                aa_buf = kmalloc(aa_g_path_max, GFP_KERNEL |
                                 __GFP_RETRY_MAYFAIL | __GFP_NOWARN);
                if (!aa_buf) {
                        destroy_buffers();
                        return -ENOMEM;
                }
                aa_put_buffer(&aa_buf->buffer[0]);
        }
        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 */

#if defined(CONFIG_NETFILTER) && defined(CONFIG_NETWORK_SECMARK)
static unsigned int apparmor_ip_postroute(void *priv,
                                          struct sk_buff *skb,
                                          const struct nf_hook_state *state)
{
        struct aa_sk_ctx *ctx;
        struct sock *sk;

        if (!skb->secmark)
                return NF_ACCEPT;

        sk = skb_to_full_sk(skb);
        if (sk == NULL)
                return NF_ACCEPT;

        ctx = SK_CTX(sk);
        if (!apparmor_secmark_check(ctx->label, OP_SENDMSG, AA_MAY_SEND,
                                    skb->secmark, sk))
                return NF_ACCEPT;

        return NF_DROP_ERR(-ECONNREFUSED);

}

static unsigned int apparmor_ipv4_postroute(void *priv,
                                            struct sk_buff *skb,
                                            const struct nf_hook_state *state)
{
        return apparmor_ip_postroute(priv, skb, state);
}

#if IS_ENABLED(CONFIG_IPV6)
static unsigned int apparmor_ipv6_postroute(void *priv,
                                            struct sk_buff *skb,
                                            const struct nf_hook_state *state)
{
        return apparmor_ip_postroute(priv, skb, state);
}
#endif

static const struct nf_hook_ops apparmor_nf_ops[] = {
        {
                .hook =         apparmor_ipv4_postroute,
                .pf =           NFPROTO_IPV4,
                .hooknum =      NF_INET_POST_ROUTING,
                .priority =     NF_IP_PRI_SELINUX_FIRST,
        },
#if IS_ENABLED(CONFIG_IPV6)
        {
                .hook =         apparmor_ipv6_postroute,
                .pf =           NFPROTO_IPV6,
                .hooknum =      NF_INET_POST_ROUTING,
                .priority =     NF_IP6_PRI_SELINUX_FIRST,
        },
#endif
};

static int __net_init apparmor_nf_register(struct net *net)
{
        int ret;

        ret = nf_register_net_hooks(net, apparmor_nf_ops,
                                    ARRAY_SIZE(apparmor_nf_ops));
        return ret;
}

static void __net_exit apparmor_nf_unregister(struct net *net)
{
        nf_unregister_net_hooks(net, apparmor_nf_ops,
                                ARRAY_SIZE(apparmor_nf_ops));
}

static struct pernet_operations apparmor_net_ops = {
        .init = apparmor_nf_register,
        .exit = apparmor_nf_unregister,
};

static int __init apparmor_nf_ip_init(void)
{
        int err;

        if (!apparmor_enabled)
                return 0;

        err = register_pernet_subsys(&apparmor_net_ops);
        if (err)
                panic("Apparmor: register_pernet_subsys: error %d\n", err);

        return 0;
}
__initcall(apparmor_nf_ip_init);
#endif

static int __init apparmor_init(void)
{
        int error;

        aa_secids_init();

        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 alloc_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 = false;
        return error;
}

DEFINE_LSM(apparmor) = {
        .name = "apparmor",
        .flags = LSM_FLAG_LEGACY_MAJOR | LSM_FLAG_EXCLUSIVE,
        .enabled = &apparmor_enabled,
        .blobs = &apparmor_blob_sizes,
        .init = apparmor_init,
};