[mirror_ubuntu-artful-kernel.git] / fs / proc / namespaces.c

#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
6b4e306a EB	1	#include <linux/proc_fs.h>
6b4e306a EB	2	#include <linux/nsproxy.h>
6b4e306a	3	#include <linux/ptrace.h>
6b4e306a EB	4	#include <linux/namei.h>
	5	#include <linux/file.h>
	6	#include <linux/utsname.h>
	7	#include <net/net_namespace.h>
6b4e306a EB	8	#include <linux/ipc_namespace.h>
6b4e306a EB	9	#include <linux/pid_namespace.h>
cde1975b	10	#include <linux/user_namespace.h>
6b4e306a EB	11	#include "internal.h"
	12
	13
	14	static const struct proc_ns_operations *ns_entries[] = {
13b6f576 EB	15	#ifdef CONFIG_NET_NS
	16	&netns_operations,
	17	#endif
34482e89 EB	18	#ifdef CONFIG_UTS_NS
	19	&utsns_operations,
	20	#endif
a00eaf11 EB	21	#ifdef CONFIG_IPC_NS
	22	&ipcns_operations,
	23	#endif
57e8391d EB	24	#ifdef CONFIG_PID_NS
57e8391d EB	25	&pidns_operations,
eaa0d190	26	&pidns_for_children_operations,
cde1975b EB	27	#endif
	28	#ifdef CONFIG_USER_NS
	29	&userns_operations,
57e8391d	30	#endif
8823c079	31	&mntns_operations,
a79a908f AK	32	#ifdef CONFIG_CGROUPS
	33	&cgroupns_operations,
	34	#endif
6b4e306a EB	35	};
6b4e306a EB	36
6b255391	37	static const char proc_ns_get_link(struct dentry dentry,
fceef393 AV	38	struct inode *inode,
fceef393 AV	39	struct delayed_call *done)
bf056bfa	40	{
3d3d35b1	41	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
bf056bfa	42	struct task_struct *task;
db04dc67	43	struct path ns_path;
bf056bfa EB	44	void *error = ERR_PTR(-EACCES);
bf056bfa EB	45
6b255391 AV	46	if (!dentry)
	47	return ERR_PTR(-ECHILD);
	48
bf056bfa EB	49	task = get_proc_task(inode);
bf056bfa EB	50	if (!task)
e149ed2b	51	return error;
bf056bfa	52
caaee623	53	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
e149ed2b AV	54	error = ns_get_path(&ns_path, task, ns_ops);
e149ed2b AV	55	if (!error)
6e77137b	56	nd_jump_link(&ns_path);
bf056bfa	57	}
bf056bfa	58	put_task_struct(task);
bf056bfa EB	59	return error;
	60	}
	61
	62	static int proc_ns_readlink(struct dentry dentry, char __user buffer, int buflen)
	63	{
2b0143b5	64	struct inode *inode = d_inode(dentry);
3d3d35b1	65	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
bf056bfa	66	struct task_struct *task;
bf056bfa	67	char name[50];
5d826c84	68	int res = -EACCES;
bf056bfa EB	69
	70	task = get_proc_task(inode);
	71	if (!task)
e149ed2b	72	return res;
bf056bfa	73
caaee623	74	if (ptrace_may_access(task, PTRACE_MODE_READ_FSCREDS)) {
e149ed2b AV	75	res = ns_get_name(name, sizeof(name), task, ns_ops);
	76	if (res >= 0)
	77	res = readlink_copy(buffer, buflen, name);
	78	}
bf056bfa	79	put_task_struct(task);
5d826c84	80	return res;
bf056bfa EB	81	}
	82
	83	static const struct inode_operations proc_ns_link_inode_operations = {
	84	.readlink = proc_ns_readlink,
6b255391	85	.get_link = proc_ns_get_link,
bf056bfa EB	86	.setattr = proc_setattr,
	87	};
	88
c52a47ac	89	static int proc_ns_instantiate(struct inode *dir,
6b4e306a EB	90	struct dentry dentry, struct task_struct task, const void *ptr)
	91	{
	92	const struct proc_ns_operations *ns_ops = ptr;
	93	struct inode *inode;
	94	struct proc_inode *ei;
6b4e306a	95
db978da8	96	inode = proc_pid_make_inode(dir->i_sb, task, S_IFLNK \| S_IRWXUGO);
6b4e306a EB	97	if (!inode)
	98	goto out;
	99
	100	ei = PROC_I(inode);
bf056bfa	101	inode->i_op = &proc_ns_link_inode_operations;
3d3d35b1	102	ei->ns_ops = ns_ops;
6b4e306a	103
1b26c9b3	104	d_set_d_op(dentry, &pid_dentry_operations);
6b4e306a EB	105	d_add(dentry, inode);
6b4e306a EB	106	/* Close the race of the process dying before we return the dentry */
0b728e19	107	if (pid_revalidate(dentry, 0))
c52a47ac	108	return 0;
6b4e306a	109	out:
c52a47ac	110	return -ENOENT;
6b4e306a EB	111	}
6b4e306a EB	112
f0c3b509	113	static int proc_ns_dir_readdir(struct file file, struct dir_context ctx)
6b4e306a	114	{
f0c3b509	115	struct task_struct *task = get_proc_task(file_inode(file));
6b4e306a	116	const struct proc_ns_operations entry, last;
6b4e306a	117
6b4e306a	118	if (!task)
f0c3b509	119	return -ENOENT;
6b4e306a	120
f0c3b509 AV	121	if (!dir_emit_dots(file, ctx))
	122	goto out;
	123	if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries))
	124	goto out;
	125	entry = ns_entries + (ctx->pos - 2);
	126	last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
	127	while (entry <= last) {
	128	const struct proc_ns_operations ops = entry;
	129	if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name),
	130	proc_ns_instantiate, task, ops))
	131	break;
	132	ctx->pos++;
	133	entry++;
	134	}
6b4e306a EB	135	out:
6b4e306a EB	136	put_task_struct(task);
f0c3b509	137	return 0;
6b4e306a EB	138	}
	139
	140	const struct file_operations proc_ns_dir_operations = {
	141	.read = generic_read_dir,
f50752ea AV	142	.iterate_shared = proc_ns_dir_readdir,
f50752ea AV	143	.llseek = generic_file_llseek,
6b4e306a EB	144	};
	145
	146	static struct dentry proc_ns_dir_lookup(struct inode dir,
00cd8dd3	147	struct dentry *dentry, unsigned int flags)
6b4e306a	148	{
c52a47ac	149	int error;
6b4e306a EB	150	struct task_struct *task = get_proc_task(dir);
	151	const struct proc_ns_operations entry, last;
	152	unsigned int len = dentry->d_name.len;
	153
c52a47ac	154	error = -ENOENT;
6b4e306a EB	155
	156	if (!task)
	157	goto out_no_task;
	158
4c619aa0 AM	159	last = &ns_entries[ARRAY_SIZE(ns_entries)];
4c619aa0 AM	160	for (entry = ns_entries; entry < last; entry++) {
6b4e306a EB	161	if (strlen((*entry)->name) != len)
	162	continue;
	163	if (!memcmp(dentry->d_name.name, (*entry)->name, len))
	164	break;
	165	}
4c619aa0	166	if (entry == last)
6b4e306a EB	167	goto out;
	168
	169	error = proc_ns_instantiate(dir, dentry, task, *entry);
	170	out:
	171	put_task_struct(task);
	172	out_no_task:
c52a47ac	173	return ERR_PTR(error);
6b4e306a EB	174	}
	175
	176	const struct inode_operations proc_ns_dir_inode_operations = {
	177	.lookup = proc_ns_dir_lookup,
	178	.getattr = pid_getattr,
	179	.setattr = proc_setattr,
	180	};