[linux-2.6-block.git] / fs / proc / namespaces.c

// SPDX-License-Identifier: GPL-2.0
#include <linux/proc_fs.h>
#include <linux/nsproxy.h>
#include <linux/ptrace.h>
#include <linux/namei.h>
#include <linux/file.h>
#include <linux/utsname.h>
#include <net/net_namespace.h>
#include <linux/ipc_namespace.h>
#include <linux/pid_namespace.h>
#include <linux/user_namespace.h>
#include "internal.h"


static const struct proc_ns_operations *ns_entries[] = {
#ifdef CONFIG_NET_NS
	&netns_operations,
#endif
#ifdef CONFIG_UTS_NS
	&utsns_operations,
#endif
#ifdef CONFIG_IPC_NS
	&ipcns_operations,
#endif
#ifdef CONFIG_PID_NS
	&pidns_operations,
	&pidns_for_children_operations,
#endif
#ifdef CONFIG_USER_NS
	&userns_operations,
#endif
	&mntns_operations,
#ifdef CONFIG_CGROUPS
	&cgroupns_operations,
#endif
};

static const char *proc_ns_get_link(struct dentry *dentry,
				    struct inode *inode,
				    struct delayed_call *done)
{
	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
	struct task_struct *task;
	struct path ns_path;
	void *error = ERR_PTR(-EACCES);

	if (!dentry)
		return ERR_PTR(-ECHILD);

	task = get_proc_task(inode);
	if (!task)
		return error;

	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
		error = ns_get_path(&ns_path, task, ns_ops);
		if (!error)
			nd_jump_link(&ns_path);
	}
	put_task_struct(task);
	return error;
}

static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int buflen)
{
	struct inode *inode = d_inode(dentry);
	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
	struct task_struct *task;
	char name[50];
	int res = -EACCES;

	task = get_proc_task(inode);
	if (!task)
		return res;

	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
		res = ns_get_name(name, sizeof(name), task, ns_ops);
		if (res >= 0)
			res = readlink_copy(buffer, buflen, name);
	}
	put_task_struct(task);
	return res;
}

static const struct inode_operations proc_ns_link_inode_operations = {
	.readlink	= proc_ns_readlink,
	.get_link	= proc_ns_get_link,
	.setattr	= proc_setattr,
};

static int proc_ns_instantiate(struct inode *dir,
	struct dentry *dentry, struct task_struct *task, const void *ptr)
{
	const struct proc_ns_operations *ns_ops = ptr;
	struct inode *inode;
	struct proc_inode *ei;

	inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK | S_IRWXUGO);
	if (!inode)
		goto out;

	ei = PROC_I(inode);
	inode->i_op = &proc_ns_link_inode_operations;
	ei->ns_ops = ns_ops;

	d_set_d_op(dentry, &pid_dentry_operations);
	d_add(dentry, inode);
	/* Close the race of the process dying before we return the dentry */
	if (pid_revalidate(dentry, 0))
		return 0;
out:
	return -ENOENT;
}

static int proc_ns_dir_readdir(struct file *file, struct dir_context *ctx)
{
	struct task_struct *task = get_proc_task(file_inode(file));
	const struct proc_ns_operations **entry, **last;

	if (!task)
		return -ENOENT;

	if (!dir_emit_dots(file, ctx))
		goto out;
	if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries))
		goto out;
	entry = ns_entries + (ctx->pos - 2);
	last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
	while (entry <= last) {
		const struct proc_ns_operations *ops = *entry;
		if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name),
				     proc_ns_instantiate, task, ops))
			break;
		ctx->pos++;
		entry++;
	}
out:
	put_task_struct(task);
	return 0;
}

const struct file_operations proc_ns_dir_operations = {
	.read		= generic_read_dir,
	.iterate_shared	= proc_ns_dir_readdir,
	.llseek		= generic_file_llseek,
};

static struct dentry *proc_ns_dir_lookup(struct inode *dir,
				struct dentry *dentry, unsigned int flags)
{
	int error;
	struct task_struct *task = get_proc_task(dir);
	const struct proc_ns_operations **entry, **last;
	unsigned int len = dentry->d_name.len;

	error = -ENOENT;

	if (!task)
		goto out_no_task;

	last = &ns_entries[ARRAY_SIZE(ns_entries)];
	for (entry = ns_entries; entry < last; entry++) {
		if (strlen((*entry)->name) != len)
			continue;
		if (!memcmp(dentry->d_name.name, (*entry)->name, len))
			break;
	}
	if (entry == last)
		goto out;

	error = proc_ns_instantiate(dir, dentry, task, *entry);
out:
	put_task_struct(task);
out_no_task:
	return ERR_PTR(error);
}

const struct inode_operations proc_ns_dir_inode_operations = {
	.lookup		= proc_ns_dir_lookup,
	.getattr	= pid_getattr,
	.setattr	= proc_setattr,
};
Commit	Line	Data
	1	// SPDX-License-Identifier: GPL-2.0
	2	#include <linux/proc_fs.h>
	3	#include <linux/nsproxy.h>
	4	#include <linux/ptrace.h>
	5	#include <linux/namei.h>
	6	#include <linux/file.h>
	7	#include <linux/utsname.h>
	8	#include <net/net_namespace.h>
	9	#include <linux/ipc_namespace.h>
	10	#include <linux/pid_namespace.h>
	11	#include <linux/user_namespace.h>
	12	#include "internal.h"
	13
	14
	15	static const struct proc_ns_operations *ns_entries[] = {
	16	#ifdef CONFIG_NET_NS
	17	&netns_operations,
	18	#endif
	19	#ifdef CONFIG_UTS_NS
	20	&utsns_operations,
	21	#endif
	22	#ifdef CONFIG_IPC_NS
	23	&ipcns_operations,
	24	#endif
	25	#ifdef CONFIG_PID_NS
	26	&pidns_operations,
	27	&pidns_for_children_operations,
	28	#endif
	29	#ifdef CONFIG_USER_NS
	30	&userns_operations,
	31	#endif
	32	&mntns_operations,
	33	#ifdef CONFIG_CGROUPS
	34	&cgroupns_operations,
	35	#endif
	36	};
	37
	38	static const char proc_ns_get_link(struct dentry dentry,
	39	struct inode *inode,
	40	struct delayed_call *done)
	41	{
	42	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
	43	struct task_struct *task;
	44	struct path ns_path;
	45	void *error = ERR_PTR(-EACCES);
	46
	47	if (!dentry)
	48	return ERR_PTR(-ECHILD);
	49
	50	task = get_proc_task(inode);
	51	if (!task)
	52	return error;
	53
	54	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
	55	error = ns_get_path(&ns_path, task, ns_ops);
	56	if (!error)
	57	nd_jump_link(&ns_path);
	58	}
	59	put_task_struct(task);
	60	return error;
	61	}
	62
	63	static int proc_ns_readlink(struct dentry dentry, char __user buffer, int buflen)
	64	{
	65	struct inode *inode = d_inode(dentry);
	66	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
	67	struct task_struct *task;
	68	char name[50];
	69	int res = -EACCES;
	70
	71	task = get_proc_task(inode);
	72	if (!task)
	73	return res;
	74
	75	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
	76	res = ns_get_name(name, sizeof(name), task, ns_ops);
	77	if (res >= 0)
	78	res = readlink_copy(buffer, buflen, name);
	79	}
	80	put_task_struct(task);
	81	return res;
	82	}
	83
	84	static const struct inode_operations proc_ns_link_inode_operations = {
	85	.readlink = proc_ns_readlink,
	86	.get_link = proc_ns_get_link,
	87	.setattr = proc_setattr,
	88	};
	89
	90	static int proc_ns_instantiate(struct inode *dir,
	91	struct dentry dentry, struct task_struct task, const void *ptr)
	92	{
	93	const struct proc_ns_operations *ns_ops = ptr;
	94	struct inode *inode;
	95	struct proc_inode *ei;
	96
	97	inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK \| S_IRWXUGO);
	98	if (!inode)
	99	goto out;
	100
	101	ei = PROC_I(inode);
	102	inode->i_op = &proc_ns_link_inode_operations;
	103	ei->ns_ops = ns_ops;
	104
	105	d_set_d_op(dentry, &pid_dentry_operations);
	106	d_add(dentry, inode);
	107	/* Close the race of the process dying before we return the dentry */
	108	if (pid_revalidate(dentry, 0))
	109	return 0;
	110	out:
	111	return -ENOENT;
	112	}
	113
	114	static int proc_ns_dir_readdir(struct file file, struct dir_context ctx)
	115	{
	116	struct task_struct *task = get_proc_task(file_inode(file));
	117	const struct proc_ns_operations entry, last;
	118
	119	if (!task)
	120	return -ENOENT;
	121
	122	if (!dir_emit_dots(file, ctx))
	123	goto out;
	124	if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries))
	125	goto out;
	126	entry = ns_entries + (ctx->pos - 2);
	127	last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
	128	while (entry <= last) {
	129	const struct proc_ns_operations ops = entry;
	130	if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name),
	131	proc_ns_instantiate, task, ops))
	132	break;
	133	ctx->pos++;
	134	entry++;
	135	}
	136	out:
	137	put_task_struct(task);
	138	return 0;
	139	}
	140
	141	const struct file_operations proc_ns_dir_operations = {
	142	.read = generic_read_dir,
	143	.iterate_shared = proc_ns_dir_readdir,
	144	.llseek = generic_file_llseek,
	145	};
	146
	147	static struct dentry proc_ns_dir_lookup(struct inode dir,
	148	struct dentry *dentry, unsigned int flags)
	149	{
	150	int error;
	151	struct task_struct *task = get_proc_task(dir);
	152	const struct proc_ns_operations entry, last;
	153	unsigned int len = dentry->d_name.len;
	154
	155	error = -ENOENT;
	156
	157	if (!task)
	158	goto out_no_task;
	159
	160	last = &ns_entries[ARRAY_SIZE(ns_entries)];
	161	for (entry = ns_entries; entry < last; entry++) {
	162	if (strlen((*entry)->name) != len)
	163	continue;
	164	if (!memcmp(dentry->d_name.name, (*entry)->name, len))
	165	break;
	166	}
	167	if (entry == last)
	168	goto out;
	169
	170	error = proc_ns_instantiate(dir, dentry, task, *entry);
	171	out:
	172	put_task_struct(task);
	173	out_no_task:
	174	return ERR_PTR(error);
	175	}
	176
	177	const struct inode_operations proc_ns_dir_inode_operations = {
	178	.lookup = proc_ns_dir_lookup,
	179	.getattr = pid_getattr,
	180	.setattr = proc_setattr,
	181	};