Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0
/*
 * fs/proc_namespace.c - handling of /proc/<pid>/{mounts,mountinfo,mountstats}
 *
 * In fact, that's a piece of procfs; it's *almost* isolated from
 * the rest of fs/proc, but has rather close relationships with
 * fs/namespace.c, thus here instead of fs/proc
 *
 */
#include <linux/mnt_namespace.h>
#include <linux/nsproxy.h>
#include <linux/security.h>
#include <linux/fs_struct.h>
#include <linux/sched/task.h>
 
#include "proc/internal.h" /* only for get_proc_task() in ->open() */
 
#include "pnode.h"
#include "internal.h"
 
static __poll_t mounts_poll(struct file *file, poll_table *wait)
{
<------>struct seq_file *m = file->private_data;
<------>struct proc_mounts *p = m->private;
<------>struct mnt_namespace *ns = p->ns;
<------>__poll_t res = EPOLLIN | EPOLLRDNORM;
<------>int event;
 
<------>poll_wait(file, &p->ns->poll, wait);
 
<------>event = READ_ONCE(ns->event);
<------>if (m->poll_event != event) {
<------><------>m->poll_event = event;
<------><------>res |= EPOLLERR | EPOLLPRI;
<------>}
 
<------>return res;
}
 
struct proc_fs_opts {
<------>int flag;
<------>const char *str;
};
 
static int show_sb_opts(struct seq_file *m, struct super_block *sb)
{
<------>static const struct proc_fs_opts fs_opts[] = {
<------><------>{ SB_SYNCHRONOUS, ",sync" },
<------><------>{ SB_DIRSYNC, ",dirsync" },
<------><------>{ SB_MANDLOCK, ",mand" },
<------><------>{ SB_LAZYTIME, ",lazytime" },
<------><------>{ 0, NULL }
<------>};
<------>const struct proc_fs_opts *fs_infop;
 
<------>for (fs_infop = fs_opts; fs_infop->flag; fs_infop++) {
<------><------>if (sb->s_flags & fs_infop->flag)
<------><------><------>seq_puts(m, fs_infop->str);
<------>}
 
<------>return security_sb_show_options(m, sb);
}
 
static void show_mnt_opts(struct seq_file *m, struct vfsmount *mnt)
{
<------>static const struct proc_fs_opts mnt_opts[] = {
<------><------>{ MNT_NOSUID, ",nosuid" },
<------><------>{ MNT_NODEV, ",nodev" },
<------><------>{ MNT_NOEXEC, ",noexec" },
<------><------>{ MNT_NOATIME, ",noatime" },
<------><------>{ MNT_NODIRATIME, ",nodiratime" },
<------><------>{ MNT_RELATIME, ",relatime" },
<------><------>{ MNT_NOSYMFOLLOW, ",nosymfollow" },
<------><------>{ 0, NULL }
<------>};
<------>const struct proc_fs_opts *fs_infop;
 
<------>for (fs_infop = mnt_opts; fs_infop->flag; fs_infop++) {
<------><------>if (mnt->mnt_flags & fs_infop->flag)
<------><------><------>seq_puts(m, fs_infop->str);
<------>}
}
 
static inline void mangle(struct seq_file *m, const char *s)
{
<------>seq_escape(m, s, " \t\n\\");
}
 
static void show_type(struct seq_file *m, struct super_block *sb)
{
<------>mangle(m, sb->s_type->name);
<------>if (sb->s_subtype) {
<------><------>seq_putc(m, '.');
<------><------>mangle(m, sb->s_subtype);
<------>}
}
 
static int show_vfsmnt(struct seq_file *m, struct vfsmount *mnt)
{
<------>struct proc_mounts *p = m->private;
<------>struct mount *r = real_mount(mnt);
<------>struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
<------>struct super_block *sb = mnt_path.dentry->d_sb;
<------>int err;
 
<------>if (sb->s_op->show_devname) {
<------><------>err = sb->s_op->show_devname(m, mnt_path.dentry);
<------><------>if (err)
<------><------><------>goto out;
<------>} else {
<------><------>mangle(m, r->mnt_devname ? r->mnt_devname : "none");
<------>}
<------>seq_putc(m, ' ');
<------>/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
<------>err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
<------>if (err)
<------><------>goto out;
<------>seq_putc(m, ' ');
<------>show_type(m, sb);
<------>seq_puts(m, __mnt_is_readonly(mnt) ? " ro" : " rw");
<------>err = show_sb_opts(m, sb);
<------>if (err)
<------><------>goto out;
<------>show_mnt_opts(m, mnt);
<------>if (sb->s_op->show_options)
<------><------>err = sb->s_op->show_options(m, mnt_path.dentry);
<------>seq_puts(m, " 0 0\n");
out:
<------>return err;
}
 
static int show_mountinfo(struct seq_file *m, struct vfsmount *mnt)
{
<------>struct proc_mounts *p = m->private;
<------>struct mount *r = real_mount(mnt);
<------>struct super_block *sb = mnt->mnt_sb;
<------>struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
<------>int err;
 
<------>seq_printf(m, "%i %i %u:%u ", r->mnt_id, r->mnt_parent->mnt_id,
<------><------>   MAJOR(sb->s_dev), MINOR(sb->s_dev));
<------>if (sb->s_op->show_path) {
<------><------>err = sb->s_op->show_path(m, mnt->mnt_root);
<------><------>if (err)
<------><------><------>goto out;
<------>} else {
<------><------>seq_dentry(m, mnt->mnt_root, " \t\n\\");
<------>}
<------>seq_putc(m, ' ');
 
<------>/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
<------>err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
<------>if (err)
<------><------>goto out;
 
<------>seq_puts(m, mnt->mnt_flags & MNT_READONLY ? " ro" : " rw");
<------>show_mnt_opts(m, mnt);
 
<------>/* Tagged fields ("foo:X" or "bar") */
<------>if (IS_MNT_SHARED(r))
<------><------>seq_printf(m, " shared:%i", r->mnt_group_id);
<------>if (IS_MNT_SLAVE(r)) {
<------><------>int master = r->mnt_master->mnt_group_id;
<------><------>int dom = get_dominating_id(r, &p->root);
<------><------>seq_printf(m, " master:%i", master);
<------><------>if (dom && dom != master)
<------><------><------>seq_printf(m, " propagate_from:%i", dom);
<------>}
<------>if (IS_MNT_UNBINDABLE(r))
<------><------>seq_puts(m, " unbindable");
 
<------>/* Filesystem specific data */
<------>seq_puts(m, " - ");
<------>show_type(m, sb);
<------>seq_putc(m, ' ');
<------>if (sb->s_op->show_devname) {
<------><------>err = sb->s_op->show_devname(m, mnt->mnt_root);
<------><------>if (err)
<------><------><------>goto out;
<------>} else {
<------><------>mangle(m, r->mnt_devname ? r->mnt_devname : "none");
<------>}
<------>seq_puts(m, sb_rdonly(sb) ? " ro" : " rw");
<------>err = show_sb_opts(m, sb);
<------>if (err)
<------><------>goto out;
<------>if (sb->s_op->show_options)
<------><------>err = sb->s_op->show_options(m, mnt->mnt_root);
<------>seq_putc(m, '\n');
out:
<------>return err;
}
 
static int show_vfsstat(struct seq_file *m, struct vfsmount *mnt)
{
<------>struct proc_mounts *p = m->private;
<------>struct mount *r = real_mount(mnt);
<------>struct path mnt_path = { .dentry = mnt->mnt_root, .mnt = mnt };
<------>struct super_block *sb = mnt_path.dentry->d_sb;
<------>int err;
 
<------>/* device */
<------>if (sb->s_op->show_devname) {
<------><------>seq_puts(m, "device ");
<------><------>err = sb->s_op->show_devname(m, mnt_path.dentry);
<------><------>if (err)
<------><------><------>goto out;
<------>} else {
<------><------>if (r->mnt_devname) {
<------><------><------>seq_puts(m, "device ");
<------><------><------>mangle(m, r->mnt_devname);
<------><------>} else
<------><------><------>seq_puts(m, "no device");
<------>}
 
<------>/* mount point */
<------>seq_puts(m, " mounted on ");
<------>/* mountpoints outside of chroot jail will give SEQ_SKIP on this */
<------>err = seq_path_root(m, &mnt_path, &p->root, " \t\n\\");
<------>if (err)
<------><------>goto out;
<------>seq_putc(m, ' ');
 
<------>/* file system type */
<------>seq_puts(m, "with fstype ");
<------>show_type(m, sb);
 
<------>/* optional statistics */
<------>if (sb->s_op->show_stats) {
<------><------>seq_putc(m, ' ');
<------><------>err = sb->s_op->show_stats(m, mnt_path.dentry);
<------>}
 
<------>seq_putc(m, '\n');
out:
<------>return err;
}
 
static int mounts_open_common(struct inode *inode, struct file *file,
<------><------><------>      int (*show)(struct seq_file *, struct vfsmount *))
{
<------>struct task_struct *task = get_proc_task(inode);
<------>struct nsproxy *nsp;
<------>struct mnt_namespace *ns = NULL;
<------>struct path root;
<------>struct proc_mounts *p;
<------>struct seq_file *m;
<------>int ret = -EINVAL;
 
<------>if (!task)
<------><------>goto err;
 
<------>task_lock(task);
<------>nsp = task->nsproxy;
<------>if (!nsp || !nsp->mnt_ns) {
<------><------>task_unlock(task);
<------><------>put_task_struct(task);
<------><------>goto err;
<------>}
<------>ns = nsp->mnt_ns;
<------>get_mnt_ns(ns);
<------>if (!task->fs) {
<------><------>task_unlock(task);
<------><------>put_task_struct(task);
<------><------>ret = -ENOENT;
<------><------>goto err_put_ns;
<------>}
<------>get_fs_root(task->fs, &root);
<------>task_unlock(task);
<------>put_task_struct(task);
 
<------>ret = seq_open_private(file, &mounts_op, sizeof(struct proc_mounts));
<------>if (ret)
<------><------>goto err_put_path;
 
<------>m = file->private_data;
<------>m->poll_event = ns->event;
 
<------>p = m->private;
<------>p->ns = ns;
<------>p->root = root;
<------>p->show = show;
<------>INIT_LIST_HEAD(&p->cursor.mnt_list);
<------>p->cursor.mnt.mnt_flags = MNT_CURSOR;
 
<------>return 0;
 
 err_put_path:
<------>path_put(&root);
 err_put_ns:
<------>put_mnt_ns(ns);
 err:
<------>return ret;
}
 
static int mounts_release(struct inode *inode, struct file *file)
{
<------>struct seq_file *m = file->private_data;
<------>struct proc_mounts *p = m->private;
<------>path_put(&p->root);
<------>mnt_cursor_del(p->ns, &p->cursor);
<------>put_mnt_ns(p->ns);
<------>return seq_release_private(inode, file);
}
 
static int mounts_open(struct inode *inode, struct file *file)
{
<------>return mounts_open_common(inode, file, show_vfsmnt);
}
 
static int mountinfo_open(struct inode *inode, struct file *file)
{
<------>return mounts_open_common(inode, file, show_mountinfo);
}
 
static int mountstats_open(struct inode *inode, struct file *file)
{
<------>return mounts_open_common(inode, file, show_vfsstat);
}
 
const struct file_operations proc_mounts_operations = {
<------>.open		= mounts_open,
<------>.read_iter	= seq_read_iter,
<------>.splice_read	= generic_file_splice_read,
<------>.llseek		= seq_lseek,
<------>.release	= mounts_release,
<------>.poll		= mounts_poll,
};
 
const struct file_operations proc_mountinfo_operations = {
<------>.open		= mountinfo_open,
<------>.read_iter	= seq_read_iter,
<------>.splice_read	= generic_file_splice_read,
<------>.llseek		= seq_lseek,
<------>.release	= mounts_release,
<------>.poll		= mounts_poll,
};
 
const struct file_operations proc_mountstats_operations = {
<------>.open		= mountstats_open,
<------>.read_iter	= seq_read_iter,
<------>.splice_read	= generic_file_splice_read,
<------>.llseek		= seq_lseek,
<------>.release	= mounts_release,
};