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

#include <linux/proc_fs.h>
#include <linux/nsproxy.h>
#include <linux/sched.h>
#include <linux/ptrace.h>
#include <linux/fs_struct.h>
#include <linux/mount.h>
#include <linux/path.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,
};

static const struct file_operations ns_file_operations = {
	.llseek		= no_llseek,
};

static const struct inode_operations ns_inode_operations = {
	.setattr	= proc_setattr,
};

static char *ns_dname(struct dentry *dentry, char *buffer, int buflen)
{
	struct inode *inode = dentry->d_inode;
	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns.ns_ops;

	return dynamic_dname(dentry, buffer, buflen, "%s:[%lu]",
		ns_ops->name, inode->i_ino);
}

const struct dentry_operations ns_dentry_operations =
{
	.d_delete	= always_delete_dentry,
	.d_dname	= ns_dname,
};

static struct dentry *proc_ns_get_dentry(struct super_block *sb,
	struct task_struct *task, const struct proc_ns_operations *ns_ops)
{
	struct dentry *dentry, *result;
	struct inode *inode;
	struct proc_inode *ei;
	struct qstr qname = { .name = "", };
	void *ns;

	ns = ns_ops->get(task);
	if (!ns)
		return ERR_PTR(-ENOENT);

	dentry = d_alloc_pseudo(sb, &qname);
	if (!dentry) {
		ns_ops->put(ns);
		return ERR_PTR(-ENOMEM);
	}

	inode = iget_locked(sb, ns_ops->inum(ns));
	if (!inode) {
		dput(dentry);
		ns_ops->put(ns);
		return ERR_PTR(-ENOMEM);
	}

	ei = PROC_I(inode);
	if (inode->i_state & I_NEW) {
		inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
		inode->i_op = &ns_inode_operations;
		inode->i_mode = S_IFREG | S_IRUGO;
		inode->i_fop = &ns_file_operations;
		ei->ns.ns_ops = ns_ops;
		ei->ns.ns = ns;
		unlock_new_inode(inode);
	} else {
		ns_ops->put(ns);
	}

	d_set_d_op(dentry, &ns_dentry_operations);
	result = d_instantiate_unique(dentry, inode);
	if (result) {
		dput(dentry);
		dentry = result;
	}

	return dentry;
}

static void *proc_ns_follow_link(struct dentry *dentry, struct nameidata *nd)
{
	struct inode *inode = dentry->d_inode;
	struct super_block *sb = inode->i_sb;
	struct proc_inode *ei = PROC_I(inode);
	struct task_struct *task;
	struct path ns_path;
	void *error = ERR_PTR(-EACCES);

	task = get_proc_task(inode);
	if (!task)
		goto out;

	if (!ptrace_may_access(task, PTRACE_MODE_READ))
		goto out_put_task;

	ns_path.dentry = proc_ns_get_dentry(sb, task, ei->ns.ns_ops);
	if (IS_ERR(ns_path.dentry)) {
		error = ERR_CAST(ns_path.dentry);
		goto out_put_task;
	}

	ns_path.mnt = mntget(nd->path.mnt);
	nd_jump_link(nd, &ns_path);
	error = NULL;

out_put_task:
	put_task_struct(task);
out:
	return error;
}

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

	task = get_proc_task(inode);
	if (!task)
		goto out;

	if (!ptrace_may_access(task, PTRACE_MODE_READ))
		goto out_put_task;

	res = -ENOENT;
	ns = ns_ops->get(task);
	if (!ns)
		goto out_put_task;

	snprintf(name, sizeof(name), "%s:[%u]", ns_ops->name, ns_ops->inum(ns));
	res = readlink_copy(buffer, buflen, name);
	ns_ops->put(ns);
out_put_task:
	put_task_struct(task);
out:
	return res;
}

static const struct inode_operations proc_ns_link_inode_operations = {
	.readlink	= proc_ns_readlink,
	.follow_link	= proc_ns_follow_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.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,
};

struct file *proc_ns_fget(int fd)
{
	struct file *file;

	file = fget(fd);
	if (!file)
		return ERR_PTR(-EBADF);

	if (file->f_op != &ns_file_operations)
		goto out_invalid;

	return file;

out_invalid:
	fput(file);
	return ERR_PTR(-EINVAL);
}

struct proc_ns *get_proc_ns(struct inode *inode)
{
	return &PROC_I(inode)->ns;
}

bool proc_ns_inode(struct inode *inode)
{
	return inode->i_fop == &ns_file_operations;
}
Commit	Line	Data
6b4e306a EB	1	#include <linux/proc_fs.h>
	2	#include <linux/nsproxy.h>
	3	#include <linux/sched.h>
	4	#include <linux/ptrace.h>
	5	#include <linux/fs_struct.h>
	6	#include <linux/mount.h>
	7	#include <linux/path.h>
	8	#include <linux/namei.h>
	9	#include <linux/file.h>
	10	#include <linux/utsname.h>
	11	#include <net/net_namespace.h>
6b4e306a EB	12	#include <linux/ipc_namespace.h>
6b4e306a EB	13	#include <linux/pid_namespace.h>
cde1975b	14	#include <linux/user_namespace.h>
6b4e306a EB	15	#include "internal.h"
	16
	17
	18	static const struct proc_ns_operations *ns_entries[] = {
13b6f576 EB	19	#ifdef CONFIG_NET_NS
	20	&netns_operations,
	21	#endif
34482e89 EB	22	#ifdef CONFIG_UTS_NS
	23	&utsns_operations,
	24	#endif
a00eaf11 EB	25	#ifdef CONFIG_IPC_NS
	26	&ipcns_operations,
	27	#endif
57e8391d EB	28	#ifdef CONFIG_PID_NS
57e8391d EB	29	&pidns_operations,
cde1975b EB	30	#endif
	31	#ifdef CONFIG_USER_NS
	32	&userns_operations,
57e8391d	33	#endif
8823c079	34	&mntns_operations,
6b4e306a EB	35	};
	36
	37	static const struct file_operations ns_file_operations = {
	38	.llseek = no_llseek,
	39	};
	40
bf056bfa EB	41	static const struct inode_operations ns_inode_operations = {
	42	.setattr = proc_setattr,
	43	};
	44
bf056bfa EB	45	static char ns_dname(struct dentry dentry, char *buffer, int buflen)
	46	{
	47	struct inode *inode = dentry->d_inode;
0bb80f24	48	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns.ns_ops;
bf056bfa EB	49
	50	return dynamic_dname(dentry, buffer, buflen, "%s:[%lu]",
	51	ns_ops->name, inode->i_ino);
	52	}
	53
	54	const struct dentry_operations ns_dentry_operations =
	55	{
b26d4cd3	56	.d_delete = always_delete_dentry,
bf056bfa EB	57	.d_dname = ns_dname,
	58	};
	59
	60	static struct dentry proc_ns_get_dentry(struct super_block sb,
	61	struct task_struct task, const struct proc_ns_operations ns_ops)
	62	{
	63	struct dentry dentry, result;
	64	struct inode *inode;
	65	struct proc_inode *ei;
	66	struct qstr qname = { .name = "", };
	67	void *ns;
	68
	69	ns = ns_ops->get(task);
	70	if (!ns)
	71	return ERR_PTR(-ENOENT);
	72
	73	dentry = d_alloc_pseudo(sb, &qname);
	74	if (!dentry) {
	75	ns_ops->put(ns);
	76	return ERR_PTR(-ENOMEM);
	77	}
	78
98f842e6	79	inode = iget_locked(sb, ns_ops->inum(ns));
bf056bfa EB	80	if (!inode) {
	81	dput(dentry);
	82	ns_ops->put(ns);
	83	return ERR_PTR(-ENOMEM);
	84	}
	85
	86	ei = PROC_I(inode);
98f842e6 EB	87	if (inode->i_state & I_NEW) {
	88	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;
	89	inode->i_op = &ns_inode_operations;
	90	inode->i_mode = S_IFREG \| S_IRUGO;
	91	inode->i_fop = &ns_file_operations;
0bb80f24 DH	92	ei->ns.ns_ops = ns_ops;
0bb80f24 DH	93	ei->ns.ns = ns;
98f842e6 EB	94	unlock_new_inode(inode);
	95	} else {
	96	ns_ops->put(ns);
	97	}
bf056bfa EB	98
	99	d_set_d_op(dentry, &ns_dentry_operations);
	100	result = d_instantiate_unique(dentry, inode);
	101	if (result) {
	102	dput(dentry);
	103	dentry = result;
	104	}
	105
	106	return dentry;
	107	}
	108
	109	static void proc_ns_follow_link(struct dentry dentry, struct nameidata *nd)
	110	{
	111	struct inode *inode = dentry->d_inode;
	112	struct super_block *sb = inode->i_sb;
	113	struct proc_inode *ei = PROC_I(inode);
	114	struct task_struct *task;
db04dc67	115	struct path ns_path;
bf056bfa EB	116	void *error = ERR_PTR(-EACCES);
	117
	118	task = get_proc_task(inode);
	119	if (!task)
	120	goto out;
	121
	122	if (!ptrace_may_access(task, PTRACE_MODE_READ))
	123	goto out_put_task;
	124
0bb80f24	125	ns_path.dentry = proc_ns_get_dentry(sb, task, ei->ns.ns_ops);
db04dc67 EB	126	if (IS_ERR(ns_path.dentry)) {
db04dc67 EB	127	error = ERR_CAST(ns_path.dentry);
bf056bfa EB	128	goto out_put_task;
	129	}
	130
db04dc67 EB	131	ns_path.mnt = mntget(nd->path.mnt);
db04dc67 EB	132	nd_jump_link(nd, &ns_path);
bf056bfa EB	133	error = NULL;
	134
	135	out_put_task:
	136	put_task_struct(task);
	137	out:
	138	return error;
	139	}
	140
	141	static int proc_ns_readlink(struct dentry dentry, char __user buffer, int buflen)
	142	{
	143	struct inode *inode = dentry->d_inode;
	144	struct proc_inode *ei = PROC_I(inode);
0bb80f24	145	const struct proc_ns_operations *ns_ops = ei->ns.ns_ops;
bf056bfa EB	146	struct task_struct *task;
	147	void *ns;
	148	char name[50];
5d826c84	149	int res = -EACCES;
bf056bfa EB	150
	151	task = get_proc_task(inode);
	152	if (!task)
	153	goto out;
	154
	155	if (!ptrace_may_access(task, PTRACE_MODE_READ))
	156	goto out_put_task;
	157
5d826c84	158	res = -ENOENT;
bf056bfa EB	159	ns = ns_ops->get(task);
	160	if (!ns)
	161	goto out_put_task;
	162
98f842e6	163	snprintf(name, sizeof(name), "%s:[%u]", ns_ops->name, ns_ops->inum(ns));
5d826c84	164	res = readlink_copy(buffer, buflen, name);
bf056bfa EB	165	ns_ops->put(ns);
	166	out_put_task:
	167	put_task_struct(task);
	168	out:
5d826c84	169	return res;
bf056bfa EB	170	}
	171
	172	static const struct inode_operations proc_ns_link_inode_operations = {
	173	.readlink = proc_ns_readlink,
	174	.follow_link = proc_ns_follow_link,
	175	.setattr = proc_setattr,
	176	};
	177
c52a47ac	178	static int proc_ns_instantiate(struct inode *dir,
6b4e306a EB	179	struct dentry dentry, struct task_struct task, const void *ptr)
	180	{
	181	const struct proc_ns_operations *ns_ops = ptr;
	182	struct inode *inode;
	183	struct proc_inode *ei;
6b4e306a EB	184
	185	inode = proc_pid_make_inode(dir->i_sb, task);
	186	if (!inode)
	187	goto out;
	188
	189	ei = PROC_I(inode);
bf056bfa EB	190	inode->i_mode = S_IFLNK\|S_IRWXUGO;
bf056bfa EB	191	inode->i_op = &proc_ns_link_inode_operations;
0bb80f24	192	ei->ns.ns_ops = ns_ops;
6b4e306a	193
1b26c9b3	194	d_set_d_op(dentry, &pid_dentry_operations);
6b4e306a EB	195	d_add(dentry, inode);
6b4e306a EB	196	/* Close the race of the process dying before we return the dentry */
0b728e19	197	if (pid_revalidate(dentry, 0))
c52a47ac	198	return 0;
6b4e306a	199	out:
c52a47ac	200	return -ENOENT;
6b4e306a EB	201	}
6b4e306a EB	202
f0c3b509	203	static int proc_ns_dir_readdir(struct file file, struct dir_context ctx)
6b4e306a	204	{
f0c3b509	205	struct task_struct *task = get_proc_task(file_inode(file));
6b4e306a	206	const struct proc_ns_operations entry, last;
6b4e306a	207
6b4e306a	208	if (!task)
f0c3b509	209	return -ENOENT;
6b4e306a	210
f0c3b509 AV	211	if (!dir_emit_dots(file, ctx))
	212	goto out;
	213	if (ctx->pos >= 2 + ARRAY_SIZE(ns_entries))
	214	goto out;
	215	entry = ns_entries + (ctx->pos - 2);
	216	last = &ns_entries[ARRAY_SIZE(ns_entries) - 1];
	217	while (entry <= last) {
	218	const struct proc_ns_operations ops = entry;
	219	if (!proc_fill_cache(file, ctx, ops->name, strlen(ops->name),
	220	proc_ns_instantiate, task, ops))
	221	break;
	222	ctx->pos++;
	223	entry++;
	224	}
6b4e306a EB	225	out:
6b4e306a EB	226	put_task_struct(task);
f0c3b509	227	return 0;
6b4e306a EB	228	}
	229
	230	const struct file_operations proc_ns_dir_operations = {
	231	.read = generic_read_dir,
f0c3b509	232	.iterate = proc_ns_dir_readdir,
6b4e306a EB	233	};
	234
	235	static struct dentry proc_ns_dir_lookup(struct inode dir,
00cd8dd3	236	struct dentry *dentry, unsigned int flags)
6b4e306a	237	{
c52a47ac	238	int error;
6b4e306a EB	239	struct task_struct *task = get_proc_task(dir);
	240	const struct proc_ns_operations entry, last;
	241	unsigned int len = dentry->d_name.len;
	242
c52a47ac	243	error = -ENOENT;
6b4e306a EB	244
	245	if (!task)
	246	goto out_no_task;
	247
4c619aa0 AM	248	last = &ns_entries[ARRAY_SIZE(ns_entries)];
4c619aa0 AM	249	for (entry = ns_entries; entry < last; entry++) {
6b4e306a EB	250	if (strlen((*entry)->name) != len)
	251	continue;
	252	if (!memcmp(dentry->d_name.name, (*entry)->name, len))
	253	break;
	254	}
4c619aa0	255	if (entry == last)
6b4e306a EB	256	goto out;
	257
	258	error = proc_ns_instantiate(dir, dentry, task, *entry);
	259	out:
	260	put_task_struct(task);
	261	out_no_task:
c52a47ac	262	return ERR_PTR(error);
6b4e306a EB	263	}
	264
	265	const struct inode_operations proc_ns_dir_inode_operations = {
	266	.lookup = proc_ns_dir_lookup,
	267	.getattr = pid_getattr,
	268	.setattr = proc_setattr,
	269	};
	270
	271	struct file *proc_ns_fget(int fd)
	272	{
	273	struct file *file;
	274
	275	file = fget(fd);
	276	if (!file)
	277	return ERR_PTR(-EBADF);
	278
	279	if (file->f_op != &ns_file_operations)
	280	goto out_invalid;
	281
	282	return file;
	283
	284	out_invalid:
	285	fput(file);
	286	return ERR_PTR(-EINVAL);
	287	}
	288
0bb80f24 DH	289	struct proc_ns get_proc_ns(struct inode inode)
	290	{
	291	return &PROC_I(inode)->ns;
	292	}
	293
8823c079 EB	294	bool proc_ns_inode(struct inode *inode)
	295	{
	296	return inode->i_fop == &ns_file_operations;
	297	}