linux-imx

// SPDX-License-Identifier: GPL-2.0

/*

 * linux/kernel/seccomp.c

 *

 * Copyright 2004-2005  Andrea Arcangeli <andrea@cpushare.com>

 *

 * Copyright (C) 2012 Google, Inc.

 * Will Drewry <wad@chromium.org>

 *

 * This defines a simple but solid secure-computing facility.

 *

 * Mode 1 uses a fixed list of allowed system calls.

 * Mode 2 allows user-defined system call filters in the form

 *        of Berkeley Packet Filters/Linux Socket Filters.

 */

​

#include <linux/refcount.h>

#include <linux/audit.h>

#include <linux/compat.h>

#include <linux/coredump.h>

#include <linux/kmemleak.h>

#include <linux/nospec.h>

#include <linux/prctl.h>

#include <linux/sched.h>

#include <linux/sched/task_stack.h>

#include <linux/seccomp.h>

#include <linux/slab.h>

#include <linux/syscalls.h>

#include <linux/sysctl.h>

​

#ifdef CONFIG_HAVE_ARCH_SECCOMP_FILTER

#include <asm/syscall.h>

#endif

​

#ifdef CONFIG_SECCOMP_FILTER

#include <linux/file.h>

#include <linux/filter.h>

#include <linux/pid.h>

#include <linux/ptrace.h>

#include <linux/security.h>

#include <linux/tracehook.h>

#include <linux/uaccess.h>

#include <linux/anon_inodes.h>

​

enum notify_state {

    SECCOMP_NOTIFY_INIT,

    SECCOMP_NOTIFY_SENT,

    SECCOMP_NOTIFY_REPLIED,

};

​

struct seccomp_knotif {

    /* The struct pid of the task whose filter triggered the notification */

    struct task_struct *task;

​

    /* The "cookie" for this request; this is unique for this filter. */

    u64 id;

​

    /*

     * The seccomp data. This pointer is valid the entire time this

     * notification is active, since it comes from __seccomp_filter which

     * eclipses the entire lifecycle here.

     */

    const struct seccomp_data *data;

​

    /*

     * Notification states. When SECCOMP_RET_USER_NOTIF is returned, a

     * struct seccomp_knotif is created and starts out in INIT. Once the

     * handler reads the notification off of an FD, it transitions to SENT.

     * If a signal is received the state transitions back to INIT and

     * another message is sent. When the userspace handler replies, state

     * transitions to REPLIED.

     */

    enum notify_state state;

​

    /* The return values, only valid when in SECCOMP_NOTIFY_REPLIED */

    int error;

    long val;

​

    /* Signals when this has entered SECCOMP_NOTIFY_REPLIED */

    struct completion ready;

​

    struct list_head list;

};

​

/**

 * struct notification - container for seccomp userspace notifications. Since

 * most seccomp filters will not have notification listeners attached and this

 * structure is fairly large, we store the notification-specific stuff in a

 * separate structure.

 *

 * @request: A semaphore that users of this notification can wait on for

 *           changes. Actual reads and writes are still controlled with