xref: /kernel/linux/linux-5.10/fs/proc/namespaces.c (revision 8c2ecf20)
18c2ecf20Sopenharmony_ci// SPDX-License-Identifier: GPL-2.0
28c2ecf20Sopenharmony_ci#include <linux/proc_fs.h>
38c2ecf20Sopenharmony_ci#include <linux/nsproxy.h>
48c2ecf20Sopenharmony_ci#include <linux/ptrace.h>
58c2ecf20Sopenharmony_ci#include <linux/namei.h>
68c2ecf20Sopenharmony_ci#include <linux/file.h>
78c2ecf20Sopenharmony_ci#include <linux/utsname.h>
88c2ecf20Sopenharmony_ci#include <net/net_namespace.h>
98c2ecf20Sopenharmony_ci#include <linux/ipc_namespace.h>
108c2ecf20Sopenharmony_ci#include <linux/pid_namespace.h>
118c2ecf20Sopenharmony_ci#include <linux/user_namespace.h>
128c2ecf20Sopenharmony_ci#include "internal.h"
138c2ecf20Sopenharmony_ci
148c2ecf20Sopenharmony_ci
158c2ecf20Sopenharmony_cistatic const struct proc_ns_operations *ns_entries[] = {
168c2ecf20Sopenharmony_ci#ifdef CONFIG_NET_NS
178c2ecf20Sopenharmony_ci	&netns_operations,
188c2ecf20Sopenharmony_ci#endif
198c2ecf20Sopenharmony_ci#ifdef CONFIG_UTS_NS
208c2ecf20Sopenharmony_ci	&utsns_operations,
218c2ecf20Sopenharmony_ci#endif
228c2ecf20Sopenharmony_ci#ifdef CONFIG_IPC_NS
238c2ecf20Sopenharmony_ci	&ipcns_operations,
248c2ecf20Sopenharmony_ci#endif
258c2ecf20Sopenharmony_ci#ifdef CONFIG_PID_NS
268c2ecf20Sopenharmony_ci	&pidns_operations,
278c2ecf20Sopenharmony_ci	&pidns_for_children_operations,
288c2ecf20Sopenharmony_ci#endif
298c2ecf20Sopenharmony_ci#ifdef CONFIG_USER_NS
308c2ecf20Sopenharmony_ci	&userns_operations,
318c2ecf20Sopenharmony_ci#endif
328c2ecf20Sopenharmony_ci	&mntns_operations,
338c2ecf20Sopenharmony_ci#ifdef CONFIG_CGROUPS
348c2ecf20Sopenharmony_ci	&cgroupns_operations,
358c2ecf20Sopenharmony_ci#endif
368c2ecf20Sopenharmony_ci#ifdef CONFIG_TIME_NS
378c2ecf20Sopenharmony_ci	&timens_operations,
388c2ecf20Sopenharmony_ci	&timens_for_children_operations,
398c2ecf20Sopenharmony_ci#endif
408c2ecf20Sopenharmony_ci};
418c2ecf20Sopenharmony_ci
428c2ecf20Sopenharmony_cistatic const char *proc_ns_get_link(struct dentry *dentry,
438c2ecf20Sopenharmony_ci				    struct inode *inode,
448c2ecf20Sopenharmony_ci				    struct delayed_call *done)
458c2ecf20Sopenharmony_ci{
468c2ecf20Sopenharmony_ci	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
478c2ecf20Sopenharmony_ci	struct task_struct *task;
488c2ecf20Sopenharmony_ci	struct path ns_path;
498c2ecf20Sopenharmony_ci	int error = -EACCES;
508c2ecf20Sopenharmony_ci
518c2ecf20Sopenharmony_ci	if (!dentry)
528c2ecf20Sopenharmony_ci		return ERR_PTR(-ECHILD);
538c2ecf20Sopenharmony_ci
548c2ecf20Sopenharmony_ci	task = get_proc_task(inode);
558c2ecf20Sopenharmony_ci	if (!task)
568c2ecf20Sopenharmony_ci		return ERR_PTR(-EACCES);
578c2ecf20Sopenharmony_ci
588c2ecf20Sopenharmony_ci	if (!ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS))
598c2ecf20Sopenharmony_ci		goto out;
608c2ecf20Sopenharmony_ci
618c2ecf20Sopenharmony_ci	error = ns_get_path(&ns_path, task, ns_ops);
628c2ecf20Sopenharmony_ci	if (error)
638c2ecf20Sopenharmony_ci		goto out;
648c2ecf20Sopenharmony_ci
658c2ecf20Sopenharmony_ci	error = nd_jump_link(&ns_path);
668c2ecf20Sopenharmony_ciout:
678c2ecf20Sopenharmony_ci	put_task_struct(task);
688c2ecf20Sopenharmony_ci	return ERR_PTR(error);
698c2ecf20Sopenharmony_ci}
708c2ecf20Sopenharmony_ci
718c2ecf20Sopenharmony_cistatic int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
728c2ecf20Sopenharmony_ci{
738c2ecf20Sopenharmony_ci	struct inode *inode = d_inode(dentry);
748c2ecf20Sopenharmony_ci	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
758c2ecf20Sopenharmony_ci	struct task_struct *task;
768c2ecf20Sopenharmony_ci	char name[50];
778c2ecf20Sopenharmony_ci	int res = -EACCES;
788c2ecf20Sopenharmony_ci
798c2ecf20Sopenharmony_ci	task = get_proc_task(inode);
808c2ecf20Sopenharmony_ci	if (!task)
818c2ecf20Sopenharmony_ci		return res;
828c2ecf20Sopenharmony_ci
838c2ecf20Sopenharmony_ci	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
848c2ecf20Sopenharmony_ci		res = ns_get_name(name, sizeof(name), task, ns_ops);
858c2ecf20Sopenharmony_ci		if (res >= 0)
868c2ecf20Sopenharmony_ci			res = readlink_copy(buffer, buflen, name);
878c2ecf20Sopenharmony_ci	}
888c2ecf20Sopenharmony_ci	put_task_struct(task);
898c2ecf20Sopenharmony_ci	return res;
908c2ecf20Sopenharmony_ci}
918c2ecf20Sopenharmony_ci
928c2ecf20Sopenharmony_cistatic const struct inode_operations proc_ns_link_inode_operations = {
938c2ecf20Sopenharmony_ci	.readlink	= proc_ns_readlink,
948c2ecf20Sopenharmony_ci	.get_link	= proc_ns_get_link,
958c2ecf20Sopenharmony_ci	.setattr	= proc_setattr,
968c2ecf20Sopenharmony_ci};
978c2ecf20Sopenharmony_ci
988c2ecf20Sopenharmony_cistatic struct dentry *proc_ns_instantiate(struct dentry *dentry,
998c2ecf20Sopenharmony_ci	struct task_struct *task, const void *ptr)
1008c2ecf20Sopenharmony_ci{
1018c2ecf20Sopenharmony_ci	const struct proc_ns_operations *ns_ops = ptr;
1028c2ecf20Sopenharmony_ci	struct inode *inode;
1038c2ecf20Sopenharmony_ci	struct proc_inode *ei;
1048c2ecf20Sopenharmony_ci
1058c2ecf20Sopenharmony_ci	inode = proc_pid_make_inode(dentry->d_sb, task, S_IFLNK | S_IRWXUGO);
1068c2ecf20Sopenharmony_ci	if (!inode)
1078c2ecf20Sopenharmony_ci		return ERR_PTR(-ENOENT);
1088c2ecf20Sopenharmony_ci
1098c2ecf20Sopenharmony_ci	ei = PROC_I(inode);
1108c2ecf20Sopenharmony_ci	inode->i_op = &proc_ns_link_inode_operations;
1118c2ecf20Sopenharmony_ci	ei->ns_ops = ns_ops;
1128c2ecf20Sopenharmony_ci	pid_update_inode(task, inode);
1138c2ecf20Sopenharmony_ci
1148c2ecf20Sopenharmony_ci	d_set_d_op(dentry, &pid_dentry_operations);
1158c2ecf20Sopenharmony_ci	return d_splice_alias(inode, dentry);
1168c2ecf20Sopenharmony_ci}
1178c2ecf20Sopenharmony_ci
1188c2ecf20Sopenharmony_cistatic int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx)
1198c2ecf20Sopenharmony_ci{
1208c2ecf20Sopenharmony_ci	struct task_struct *task = get_proc_task(file_inode(file));
1218c2ecf20Sopenharmony_ci	const struct proc_ns_operations **entry, **last;
1228c2ecf20Sopenharmony_ci
1238c2ecf20Sopenharmony_ci	if (!task)
1248c2ecf20Sopenharmony_ci		return -ENOENT;
1258c2ecf20Sopenharmony_ci
1268c2ecf20Sopenharmony_ci	if (!dir_emit_dots(file, ctx))
1278c2ecf20Sopenharmony_ci		goto out;
1288c2ecf20Sopenharmony_ci	if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries))
1298c2ecf20Sopenharmony_ci		goto out;
1308c2ecf20Sopenharmony_ci	entry = ns_entries + (ctx->pos - 2);
1318c2ecf20Sopenharmony_ci	last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
1328c2ecf20Sopenharmony_ci	while (entry <= last) {
1338c2ecf20Sopenharmony_ci		const struct proc_ns_operations *ops = *entry;
1348c2ecf20Sopenharmony_ci		if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name),
1358c2ecf20Sopenharmony_ci				     proc_ns_instantiate, task, ops))
1368c2ecf20Sopenharmony_ci			break;
1378c2ecf20Sopenharmony_ci		ctx->pos++;
1388c2ecf20Sopenharmony_ci		entry++;
1398c2ecf20Sopenharmony_ci	}
1408c2ecf20Sopenharmony_ciout:
1418c2ecf20Sopenharmony_ci	put_task_struct(task);
1428c2ecf20Sopenharmony_ci	return 0;
1438c2ecf20Sopenharmony_ci}
1448c2ecf20Sopenharmony_ci
1458c2ecf20Sopenharmony_ciconst struct file_operations proc_ns_dir_operations = {
1468c2ecf20Sopenharmony_ci	.read		= generic_read_dir,
1478c2ecf20Sopenharmony_ci	.iterate_shared	= proc_ns_dir_readdir,
1488c2ecf20Sopenharmony_ci	.llseek		= generic_file_llseek,
1498c2ecf20Sopenharmony_ci};
1508c2ecf20Sopenharmony_ci
1518c2ecf20Sopenharmony_cistatic struct dentry *proc_ns_dir_lookup(struct inode *dir,
1528c2ecf20Sopenharmony_ci				struct dentry *dentry, unsigned int flags)
1538c2ecf20Sopenharmony_ci{
1548c2ecf20Sopenharmony_ci	struct task_struct *task = get_proc_task(dir);
1558c2ecf20Sopenharmony_ci	const struct proc_ns_operations **entry, **last;
1568c2ecf20Sopenharmony_ci	unsigned int len = dentry->d_name.len;
1578c2ecf20Sopenharmony_ci	struct dentry *res = ERR_PTR(-ENOENT);
1588c2ecf20Sopenharmony_ci
1598c2ecf20Sopenharmony_ci	if (!task)
1608c2ecf20Sopenharmony_ci		goto out_no_task;
1618c2ecf20Sopenharmony_ci
1628c2ecf20Sopenharmony_ci	last = &ns_entries[ARRAY_SIZE(ns_entries)];
1638c2ecf20Sopenharmony_ci	for (entry = ns_entries; entry < last; entry++) {
1648c2ecf20Sopenharmony_ci		if (strlen((*entry)->name) != len)
1658c2ecf20Sopenharmony_ci			continue;
1668c2ecf20Sopenharmony_ci		if (!memcmp(dentry->d_name.name, (*entry)->name, len))
1678c2ecf20Sopenharmony_ci			break;
1688c2ecf20Sopenharmony_ci	}
1698c2ecf20Sopenharmony_ci	if (entry == last)
1708c2ecf20Sopenharmony_ci		goto out;
1718c2ecf20Sopenharmony_ci
1728c2ecf20Sopenharmony_ci	res = proc_ns_instantiate(dentry, task, *entry);
1738c2ecf20Sopenharmony_ciout:
1748c2ecf20Sopenharmony_ci	put_task_struct(task);
1758c2ecf20Sopenharmony_ciout_no_task:
1768c2ecf20Sopenharmony_ci	return res;
1778c2ecf20Sopenharmony_ci}
1788c2ecf20Sopenharmony_ci
1798c2ecf20Sopenharmony_ciconst struct inode_operations proc_ns_dir_inode_operations = {
1808c2ecf20Sopenharmony_ci	.lookup		= proc_ns_dir_lookup,
1818c2ecf20Sopenharmony_ci	.getattr	= pid_getattr,
1828c2ecf20Sopenharmony_ci	.setattr	= proc_setattr,
1838c2ecf20Sopenharmony_ci};
184