[deliverable/linux.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,
#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);
	if (!inode)
		goto out;

	ei = PROC_I(inode);
	inode->i_mode = S_IFLNK|S_IRWXUGO;
	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	= proc_ns_dir_readdir,
};

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