| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * linux/fs/proc/root.c |
| * |
| * Copyright (C) 1991, 1992 Linus Torvalds |
| * |
| * proc root directory handling functions |
| */ |
| |
| #include <linux/uaccess.h> |
| |
| #include <linux/errno.h> |
| #include <linux/time.h> |
| #include <linux/proc_fs.h> |
| #include <linux/stat.h> |
| #include <linux/init.h> |
| #include <linux/sched.h> |
| #include <linux/sched/stat.h> |
| #include <linux/module.h> |
| #include <linux/bitops.h> |
| #include <linux/user_namespace.h> |
| #include <linux/mount.h> |
| #include <linux/pid_namespace.h> |
| #include <linux/parser.h> |
| #include <linux/cred.h> |
| |
| #include "internal.h" |
| |
| enum { |
| Opt_gid, Opt_hidepid, Opt_err, |
| }; |
| |
| static const match_table_t tokens = { |
| {Opt_hidepid, "hidepid=%u"}, |
| {Opt_gid, "gid=%u"}, |
| {Opt_err, NULL}, |
| }; |
| |
| int proc_parse_options(char *options, struct pid_namespace *pid) |
| { |
| char *p; |
| substring_t args[MAX_OPT_ARGS]; |
| int option; |
| |
| if (!options) |
| return 1; |
| |
| while ((p = strsep(&options, ",")) != NULL) { |
| int token; |
| if (!*p) |
| continue; |
| |
| args[0].to = args[0].from = NULL; |
| token = match_token(p, tokens, args); |
| switch (token) { |
| case Opt_gid: |
| if (match_int(&args[0], &option)) |
| return 0; |
| pid->pid_gid = make_kgid(current_user_ns(), option); |
| break; |
| case Opt_hidepid: |
| if (match_int(&args[0], &option)) |
| return 0; |
| if (option < HIDEPID_OFF || |
| option > HIDEPID_INVISIBLE) { |
| pr_err("proc: hidepid value must be between 0 and 2.\n"); |
| return 0; |
| } |
| pid->hide_pid = option; |
| break; |
| default: |
| pr_err("proc: unrecognized mount option \"%s\" " |
| "or missing value\n", p); |
| return 0; |
| } |
| } |
| |
| return 1; |
| } |
| |
| int proc_remount(struct super_block *sb, int *flags, char *data) |
| { |
| struct pid_namespace *pid = sb->s_fs_info; |
| |
| sync_filesystem(sb); |
| return !proc_parse_options(data, pid); |
| } |
| |
| static struct dentry *proc_mount(struct file_system_type *fs_type, |
| int flags, const char *dev_name, void *data) |
| { |
| struct pid_namespace *ns; |
| |
| if (flags & SB_KERNMOUNT) { |
| ns = data; |
| data = NULL; |
| } else { |
| ns = task_active_pid_ns(current); |
| } |
| |
| return mount_ns(fs_type, flags, data, ns, ns->user_ns, proc_fill_super); |
| } |
| |
| static void proc_kill_sb(struct super_block *sb) |
| { |
| struct pid_namespace *ns; |
| |
| ns = (struct pid_namespace *)sb->s_fs_info; |
| if (ns->proc_self) |
| dput(ns->proc_self); |
| if (ns->proc_thread_self) |
| dput(ns->proc_thread_self); |
| kill_anon_super(sb); |
| put_pid_ns(ns); |
| } |
| |
| static struct file_system_type proc_fs_type = { |
| .name = "proc", |
| .mount = proc_mount, |
| .kill_sb = proc_kill_sb, |
| .fs_flags = FS_USERNS_MOUNT, |
| }; |
| |
| void __init proc_root_init(void) |
| { |
| int err; |
| |
| proc_init_inodecache(); |
| set_proc_pid_nlink(); |
| err = register_filesystem(&proc_fs_type); |
| if (err) |
| return; |
| |
| proc_self_init(); |
| proc_thread_self_init(); |
| proc_symlink("mounts", NULL, "self/mounts"); |
| |
| proc_net_init(); |
| proc_mkdir("fs", NULL); |
| proc_mkdir("driver", NULL); |
| proc_create_mount_point("fs/nfsd"); /* somewhere for the nfsd filesystem to be mounted */ |
| #if defined(CONFIG_SUN_OPENPROMFS) || defined(CONFIG_SUN_OPENPROMFS_MODULE) |
| /* just give it a mountpoint */ |
| proc_create_mount_point("openprom"); |
| #endif |
| proc_tty_init(); |
| proc_mkdir("bus", NULL); |
| proc_sys_init(); |
| } |
| |
| static int proc_root_getattr(const struct path *path, struct kstat *stat, |
| u32 request_mask, unsigned int query_flags) |
| { |
| generic_fillattr(d_inode(path->dentry), stat); |
| stat->nlink = proc_root.nlink + nr_processes(); |
| return 0; |
| } |
| |
| static struct dentry *proc_root_lookup(struct inode * dir, struct dentry * dentry, unsigned int flags) |
| { |
| if (!proc_pid_lookup(dir, dentry, flags)) |
| return NULL; |
| |
| return proc_lookup(dir, dentry, flags); |
| } |
| |
| static int proc_root_readdir(struct file *file, struct dir_context *ctx) |
| { |
| if (ctx->pos < FIRST_PROCESS_ENTRY) { |
| int error = proc_readdir(file, ctx); |
| if (unlikely(error <= 0)) |
| return error; |
| ctx->pos = FIRST_PROCESS_ENTRY; |
| } |
| |
| return proc_pid_readdir(file, ctx); |
| } |
| |
| /* |
| * The root /proc directory is special, as it has the |
| * <pid> directories. Thus we don't use the generic |
| * directory handling functions for that.. |
| */ |
| static const struct file_operations proc_root_operations = { |
| .read = generic_read_dir, |
| .iterate_shared = proc_root_readdir, |
| .llseek = generic_file_llseek, |
| }; |
| |
| /* |
| * proc root can do almost nothing.. |
| */ |
| static const struct inode_operations proc_root_inode_operations = { |
| .lookup = proc_root_lookup, |
| .getattr = proc_root_getattr, |
| }; |
| |
| /* |
| * This is the root "inode" in the /proc tree.. |
| */ |
| struct proc_dir_entry proc_root = { |
| .low_ino = PROC_ROOT_INO, |
| .namelen = 5, |
| .mode = S_IFDIR | S_IRUGO | S_IXUGO, |
| .nlink = 2, |
| .count = ATOMIC_INIT(1), |
| .proc_iops = &proc_root_inode_operations, |
| .proc_fops = &proc_root_operations, |
| .parent = &proc_root, |
| .subdir = RB_ROOT_CACHED, |
| .name = "/proc", |
| }; |
| |
| int pid_ns_prepare_proc(struct pid_namespace *ns) |
| { |
| struct vfsmount *mnt; |
| |
| mnt = kern_mount_data(&proc_fs_type, ns); |
| if (IS_ERR(mnt)) |
| return PTR_ERR(mnt); |
| |
| ns->proc_mnt = mnt; |
| return 0; |
| } |
| |
| void pid_ns_release_proc(struct pid_namespace *ns) |
| { |
| kern_unmount(ns->proc_mnt); |
| } |