[mirror_ubuntu-bionic-kernel.git] / fs / nfs / nfs4namespace.c

/*
 * linux/fs/nfs/nfs4namespace.c
 *
 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
 * - Modified by David Howells <dhowells@redhat.com>
 *
 * NFSv4 namespace
 */

#include <linux/dcache.h>
#include <linux/mount.h>
#include <linux/namei.h>
#include <linux/nfs_fs.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/vfs.h>
#include <linux/inet.h>
#include "internal.h"
#include "nfs4_fs.h"
#include "dns_resolve.h"

#define NFSDBG_FACILITY		NFSDBG_VFS

/*
 * Convert the NFSv4 pathname components into a standard posix path.
 *
 * Note that the resulting string will be placed at the end of the buffer
 */
static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
					 char *buffer, ssize_t buflen)
{
	char *end = buffer + buflen;
	int n;

	*--end = '\0';
	buflen--;

	n = pathname->ncomponents;
	while (--n >= 0) {
		const struct nfs4_string *component = &pathname->components[n];
		buflen -= component->len + 1;
		if (buflen < 0)
			goto Elong;
		end -= component->len;
		memcpy(end, component->data, component->len);
		*--end = '/';
	}
	return end;
Elong:
	return ERR_PTR(-ENAMETOOLONG);
}

/*
 * return the path component of "<server>:<path>"
 *  nfspath - the "<server>:<path>" string
 *  end - one past the last char that could contain "<server>:"
 * returns NULL on failure
 */
static char *nfs_path_component(const char *nfspath, const char *end)
{
	char *p;

	if (*nfspath == '[') {
		/* parse [] escaped IPv6 addrs */
		p = strchr(nfspath, ']');
		if (p != NULL && ++p < end && *p == ':')
			return p + 1;
	} else {
		/* otherwise split on first colon */
		p = strchr(nfspath, ':');
		if (p != NULL && p < end)
			return p + 1;
	}
	return NULL;
}

/*
 * Determine the mount path as a string
 */
static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
{
	char *limit;
	char *path = nfs_path(&limit, dentry, buffer, buflen);
	if (!IS_ERR(path)) {
		char *path_component = nfs_path_component(path, limit);
		if (path_component)
			return path_component;
	}
	return path;
}

/*
 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
 * believe to be the server path to this dentry
 */
static int nfs4_validate_fspath(struct dentry *dentry,
				const struct nfs4_fs_locations *locations,
				char *page, char *page2)
{
	const char *path, *fs_path;

	path = nfs4_path(dentry, page, PAGE_SIZE);
	if (IS_ERR(path))
		return PTR_ERR(path);

	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	if (IS_ERR(fs_path))
		return PTR_ERR(fs_path);

	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
		dprintk("%s: path %s does not begin with fsroot %s\n",
			__func__, path, fs_path);
		return -ENOENT;
	}

	return 0;
}

static size_t nfs_parse_server_name(char *string, size_t len,
		struct sockaddr *sa, size_t salen, struct nfs_server *server)
{
	struct net *net = rpc_net_ns(server->client);
	ssize_t ret;

	ret = rpc_pton(net, string, len, sa, salen);
	if (ret == 0) {
		ret = nfs_dns_resolve_name(net, string, len, sa, salen);
		if (ret < 0)
			ret = 0;
	}
	return ret;
}

static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name)
{
	struct page *page;
	struct nfs4_secinfo_flavors *flavors;
	rpc_authflavor_t flavor;
	int err;

	page = alloc_page(GFP_KERNEL);
	if (!page)
		return -ENOMEM;
	flavors = page_address(page);

	err = nfs4_proc_secinfo(inode, name, flavors);
	if (err < 0) {
		flavor = err;
		goto out;
	}

	flavor = nfs_find_best_sec(flavors);

out:
	put_page(page);
	return flavor;
}

/*
 * Please call rpc_shutdown_client() when you are done with this client.
 */
struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode,
					struct qstr *name)
{
	struct rpc_clnt *clone;
	struct rpc_auth *auth;
	rpc_authflavor_t flavor;

	flavor = nfs4_negotiate_security(inode, name);
	if (flavor < 0)
		return ERR_PTR(flavor);

	clone = rpc_clone_client(clnt);
	if (IS_ERR(clone))
		return clone;

	auth = rpcauth_create(flavor, clone);
	if (!auth) {
		rpc_shutdown_client(clone);
		clone = ERR_PTR(-EIO);
	}

	return clone;
}

static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
				     char *page, char *page2,
				     const struct nfs4_fs_location *location)
{
	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	char *mnt_path;
	unsigned int maxbuflen;
	unsigned int s;

	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	if (IS_ERR(mnt_path))
		return ERR_CAST(mnt_path);
	mountdata->mnt_path = mnt_path;
	maxbuflen = mnt_path - 1 - page2;

	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
	if (mountdata->addr == NULL)
		return ERR_PTR(-ENOMEM);

	for (s = 0; s < location->nservers; s++) {
		const struct nfs4_string *buf = &location->servers[s];

		if (buf->len <= 0 || buf->len >= maxbuflen)
			continue;

		if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
			continue;

		mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
				mountdata->addr, addr_bufsize,
				NFS_SB(mountdata->sb));
		if (mountdata->addrlen == 0)
			continue;

		rpc_set_port(mountdata->addr, NFS_PORT);

		memcpy(page2, buf->data, buf->len);
		page2[buf->len] = '\0';
		mountdata->hostname = page2;

		snprintf(page, PAGE_SIZE, "%s:%s",
				mountdata->hostname,
				mountdata->mnt_path);

		mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
		if (!IS_ERR(mnt))
			break;
	}
	kfree(mountdata->addr);
	return mnt;
}

/**
 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
 * @dentry - parent directory
 * @locations - array of NFSv4 server location information
 *
 */
static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
					    const struct nfs4_fs_locations *locations)
{
	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	struct nfs_clone_mount mountdata = {
		.sb = dentry->d_sb,
		.dentry = dentry,
		.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
	};
	char *page = NULL, *page2 = NULL;
	int loc, error;

	if (locations == NULL || locations->nlocations <= 0)
		goto out;

	dprintk("%s: referral at %s/%s\n", __func__,
		dentry->d_parent->d_name.name, dentry->d_name.name);

	page = (char *) __get_free_page(GFP_USER);
	if (!page)
		goto out;

	page2 = (char *) __get_free_page(GFP_USER);
	if (!page2)
		goto out;

	/* Ensure fs path is a prefix of current dentry path */
	error = nfs4_validate_fspath(dentry, locations, page, page2);
	if (error < 0) {
		mnt = ERR_PTR(error);
		goto out;
	}

	for (loc = 0; loc < locations->nlocations; loc++) {
		const struct nfs4_fs_location *location = &locations->locations[loc];

		if (location == NULL || location->nservers <= 0 ||
		    location->rootpath.ncomponents == 0)
			continue;

		mnt = try_location(&mountdata, page, page2, location);
		if (!IS_ERR(mnt))
			break;
	}

out:
	free_page((unsigned long) page);
	free_page((unsigned long) page2);
	dprintk("%s: done\n", __func__);
	return mnt;
}

/*
 * nfs_do_refmount - handle crossing a referral on server
 * @dentry - dentry of referral
 *
 */
struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
{
	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
	struct dentry *parent;
	struct nfs4_fs_locations *fs_locations = NULL;
	struct page *page;
	int err;

	/* BUG_ON(IS_ROOT(dentry)); */
	dprintk("%s: enter\n", __func__);

	page = alloc_page(GFP_KERNEL);
	if (page == NULL)
		goto out;

	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	if (fs_locations == NULL)
		goto out_free;

	/* Get locations */
	mnt = ERR_PTR(-ENOENT);

	parent = dget_parent(dentry);
	dprintk("%s: getting locations for %s/%s\n",
		__func__, parent->d_name.name, dentry->d_name.name);

	err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
	dput(parent);
	if (err != 0 ||
	    fs_locations->nlocations <= 0 ||
	    fs_locations->fs_path.ncomponents <= 0)
		goto out_free;

	mnt = nfs_follow_referral(dentry, fs_locations);
out_free:
	__free_page(page);
	kfree(fs_locations);
out:
	dprintk("%s: done\n", __func__);
	return mnt;
}
Commit	Line	Data
f7b422b1 DH	1	/*
	2	* linux/fs/nfs/nfs4namespace.c
	3	*
	4	* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
54ceac45	5	* - Modified by David Howells <dhowells@redhat.com>
f7b422b1 DH	6	*
	7	* NFSv4 namespace
	8	*/
	9
f7b422b1 DH	10	#include <linux/dcache.h>
	11	#include <linux/mount.h>
	12	#include <linux/namei.h>
	13	#include <linux/nfs_fs.h>
5a0e3ad6	14	#include <linux/slab.h>
f7b422b1 DH	15	#include <linux/string.h>
	16	#include <linux/sunrpc/clnt.h>
	17	#include <linux/vfs.h>
	18	#include <linux/inet.h>
	19	#include "internal.h"
c228fd3a	20	#include "nfs4_fs.h"
7d7ea882	21	#include "dns_resolve.h"
f7b422b1 DH	22
	23	#define NFSDBG_FACILITY NFSDBG_VFS
	24
	25	/*
ef95d31e TM	26	* Convert the NFSv4 pathname components into a standard posix path.
	27	*
	28	* Note that the resulting string will be placed at the end of the buffer
f7b422b1	29	*/
509de811	30	static inline char nfs4_pathname_string(const struct nfs4_pathname pathname,
f7b422b1 DH	31	char *buffer, ssize_t buflen)
	32	{
	33	char *end = buffer + buflen;
	34	int n;
	35
	36	*--end = '\0';
	37	buflen--;
	38
	39	n = pathname->ncomponents;
	40	while (--n >= 0) {
509de811	41	const struct nfs4_string *component = &pathname->components[n];
f7b422b1 DH	42	buflen -= component->len + 1;
	43	if (buflen < 0)
	44	goto Elong;
	45	end -= component->len;
	46	memcpy(end, component->data, component->len);
	47	*--end = '/';
	48	}
	49	return end;
	50	Elong:
	51	return ERR_PTR(-ENAMETOOLONG);
	52	}
	53
1aba1567 WAA	54	/*
	55	* return the path component of "<server>:<path>"
	56	* nfspath - the "<server>:<path>" string
	57	* end - one past the last char that could contain "<server>:"
	58	* returns NULL on failure
	59	*/
	60	static char nfs_path_component(const char nfspath, const char *end)
	61	{
	62	char *p;
	63
	64	if (*nfspath == '[') {
	65	/* parse [] escaped IPv6 addrs */
	66	p = strchr(nfspath, ']');
	67	if (p != NULL && ++p < end && *p == ':')
	68	return p + 1;
	69	} else {
	70	/* otherwise split on first colon */
	71	p = strchr(nfspath, ':');
	72	if (p != NULL && p < end)
	73	return p + 1;
	74	}
	75	return NULL;
	76	}
	77
54ceac45 DH	78	/*
	79	* Determine the mount path as a string
	80	*/
b514f872	81	static char nfs4_path(struct dentry dentry, char *buffer, ssize_t buflen)
54ceac45	82	{
b514f872 AV	83	char *limit;
	84	char *path = nfs_path(&limit, dentry, buffer, buflen);
	85	if (!IS_ERR(path)) {
1aba1567 WAA	86	char *path_component = nfs_path_component(path, limit);
	87	if (path_component)
	88	return path_component;
b514f872 AV	89	}
b514f872 AV	90	return path;
54ceac45 DH	91	}
	92
	93	/*
	94	* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
	95	* believe to be the server path to this dentry
	96	*/
b514f872	97	static int nfs4_validate_fspath(struct dentry *dentry,
54ceac45 DH	98	const struct nfs4_fs_locations *locations,
	99	char page, char page2)
	100	{
	101	const char path, fs_path;
	102
b514f872	103	path = nfs4_path(dentry, page, PAGE_SIZE);
54ceac45 DH	104	if (IS_ERR(path))
	105	return PTR_ERR(path);
	106
	107	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	108	if (IS_ERR(fs_path))
	109	return PTR_ERR(fs_path);
	110
	111	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
	112	dprintk("%s: path %s does not begin with fsroot %s\n",
3110ff80	113	__func__, path, fs_path);
54ceac45 DH	114	return -ENOENT;
	115	}
	116
	117	return 0;
	118	}
	119
7d7ea882	120	static size_t nfs_parse_server_name(char *string, size_t len,
1b340d01	121	struct sockaddr sa, size_t salen, struct nfs_server server)
7d7ea882	122	{
2446ab60	123	struct net *net = rpc_net_ns(server->client);
7d7ea882 TM	124	ssize_t ret;
7d7ea882 TM	125
33faaa38	126	ret = rpc_pton(net, string, len, sa, salen);
7d7ea882	127	if (ret == 0) {
33faaa38	128	ret = nfs_dns_resolve_name(net, string, len, sa, salen);
7d7ea882 TM	129	if (ret < 0)
	130	ret = 0;
	131	}
	132	return ret;
	133	}
	134
72de53ec BS	135	static rpc_authflavor_t nfs4_negotiate_security(struct inode inode, struct qstr name)
	136	{
	137	struct page *page;
	138	struct nfs4_secinfo_flavors *flavors;
	139	rpc_authflavor_t flavor;
	140	int err;
	141
	142	page = alloc_page(GFP_KERNEL);
	143	if (!page)
	144	return -ENOMEM;
	145	flavors = page_address(page);
	146
	147	err = nfs4_proc_secinfo(inode, name, flavors);
	148	if (err < 0) {
	149	flavor = err;
	150	goto out;
	151	}
	152
	153	flavor = nfs_find_best_sec(flavors);
	154
	155	out:
	156	put_page(page);
	157	return flavor;
	158	}
	159
	160	/*
	161	* Please call rpc_shutdown_client() when you are done with this client.
	162	*/
	163	struct rpc_clnt nfs4_create_sec_client(struct rpc_clnt clnt, struct inode *inode,
	164	struct qstr *name)
	165	{
	166	struct rpc_clnt *clone;
	167	struct rpc_auth *auth;
	168	rpc_authflavor_t flavor;
	169
	170	flavor = nfs4_negotiate_security(inode, name);
	171	if (flavor < 0)
	172	return ERR_PTR(flavor);
	173
	174	clone = rpc_clone_client(clnt);
	175	if (IS_ERR(clone))
	176	return clone;
	177
	178	auth = rpcauth_create(flavor, clone);
	179	if (!auth) {
	180	rpc_shutdown_client(clone);
	181	clone = ERR_PTR(-EIO);
	182	}
	183
	184	return clone;
	185	}
	186
4ada29d5 BF	187	static struct vfsmount try_location(struct nfs_clone_mount mountdata,
	188	char page, char page2,
	189	const struct nfs4_fs_location *location)
	190	{
364d015e	191	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
4ada29d5 BF	192	struct vfsmount *mnt = ERR_PTR(-ENOENT);
4ada29d5 BF	193	char *mnt_path;
ef95d31e	194	unsigned int maxbuflen;
460cdbc8	195	unsigned int s;
4ada29d5 BF	196
	197	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	198	if (IS_ERR(mnt_path))
517be09d	199	return ERR_CAST(mnt_path);
4ada29d5	200	mountdata->mnt_path = mnt_path;
ef95d31e	201	maxbuflen = mnt_path - 1 - page2;
4ada29d5	202
364d015e TM	203	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
	204	if (mountdata->addr == NULL)
	205	return ERR_PTR(-ENOMEM);
	206
460cdbc8	207	for (s = 0; s < location->nservers; s++) {
ea31a443	208	const struct nfs4_string *buf = &location->servers[s];
4ada29d5	209
ef95d31e	210	if (buf->len <= 0 \|\| buf->len >= maxbuflen)
4ada29d5	211	continue;
4ada29d5	212
ea31a443 BF	213	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
ea31a443 BF	214	continue;
517be09d TM	215
517be09d TM	216	mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
1b340d01 SK	217	mountdata->addr, addr_bufsize,
1b340d01 SK	218	NFS_SB(mountdata->sb));
53a0b9c4	219	if (mountdata->addrlen == 0)
ea31a443	220	continue;
517be09d	221
ec6ee612	222	rpc_set_port(mountdata->addr, NFS_PORT);
ea31a443	223
ef95d31e TM	224	memcpy(page2, buf->data, buf->len);
ef95d31e TM	225	page2[buf->len] = '\0';
ea31a443	226	mountdata->hostname = page2;
4ada29d5 BF	227
	228	snprintf(page, PAGE_SIZE, "%s:%s",
	229	mountdata->hostname,
	230	mountdata->mnt_path);
	231
	232	mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
	233	if (!IS_ERR(mnt))
	234	break;
4ada29d5	235	}
364d015e	236	kfree(mountdata->addr);
4ada29d5 BF	237	return mnt;
	238	}
	239
f7b422b1 DH	240	/**
f7b422b1 DH	241	* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
f7b422b1	242	* @dentry - parent directory
3f43c666	243	* @locations - array of NFSv4 server location information
f7b422b1 DH	244	*
f7b422b1 DH	245	*/
f8ad9c4b	246	static struct vfsmount nfs_follow_referral(struct dentry dentry,
509de811	247	const struct nfs4_fs_locations *locations)
f7b422b1 DH	248	{
	249	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	250	struct nfs_clone_mount mountdata = {
f8ad9c4b	251	.sb = dentry->d_sb,
f7b422b1	252	.dentry = dentry,
f8ad9c4b	253	.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
f7b422b1	254	};
54ceac45	255	char page = NULL, page2 = NULL;
3f43c666	256	int loc, error;
f7b422b1 DH	257
	258	if (locations == NULL \|\| locations->nlocations <= 0)
	259	goto out;
	260
3110ff80	261	dprintk("%s: referral at %s/%s\n", __func__,
f7b422b1 DH	262	dentry->d_parent->d_name.name, dentry->d_name.name);
f7b422b1 DH	263
f7b422b1	264	page = (char *) __get_free_page(GFP_USER);
54ceac45	265	if (!page)
f7b422b1	266	goto out;
54ceac45	267
f7b422b1	268	page2 = (char *) __get_free_page(GFP_USER);
54ceac45	269	if (!page2)
f7b422b1 DH	270	goto out;
f7b422b1 DH	271
54ceac45	272	/* Ensure fs path is a prefix of current dentry path */
b514f872	273	error = nfs4_validate_fspath(dentry, locations, page, page2);
54ceac45 DH	274	if (error < 0) {
	275	mnt = ERR_PTR(error);
	276	goto out;
f7b422b1 DH	277	}
f7b422b1 DH	278
460cdbc8	279	for (loc = 0; loc < locations->nlocations; loc++) {
509de811	280	const struct nfs4_fs_location *location = &locations->locations[loc];
f7b422b1 DH	281
f7b422b1 DH	282	if (location == NULL \|\| location->nservers <= 0 \|\|
460cdbc8	283	location->rootpath.ncomponents == 0)
f7b422b1	284	continue;
f7b422b1	285
4ada29d5 BF	286	mnt = try_location(&mountdata, page, page2, location);
	287	if (!IS_ERR(mnt))
	288	break;
f7b422b1 DH	289	}
f7b422b1 DH	290
f7b422b1	291	out:
54ceac45 DH	292	free_page((unsigned long) page);
54ceac45 DH	293	free_page((unsigned long) page2);
3110ff80	294	dprintk("%s: done\n", __func__);
f7b422b1 DH	295	return mnt;
	296	}
	297
	298	/*
	299	* nfs_do_refmount - handle crossing a referral on server
	300	* @dentry - dentry of referral
f7b422b1 DH	301	*
f7b422b1 DH	302	*/
f05d147f	303	struct vfsmount nfs_do_refmount(struct rpc_clnt client, struct dentry *dentry)
f7b422b1	304	{
54ceac45	305	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
f7b422b1 DH	306	struct dentry *parent;
	307	struct nfs4_fs_locations *fs_locations = NULL;
	308	struct page *page;
	309	int err;
	310
	311	/* BUG_ON(IS_ROOT(dentry)); */
3110ff80	312	dprintk("%s: enter\n", __func__);
f7b422b1 DH	313
	314	page = alloc_page(GFP_KERNEL);
	315	if (page == NULL)
	316	goto out;
	317
	318	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	319	if (fs_locations == NULL)
	320	goto out_free;
	321
	322	/* Get locations */
54ceac45 DH	323	mnt = ERR_PTR(-ENOENT);
54ceac45 DH	324
f7b422b1	325	parent = dget_parent(dentry);
54ceac45	326	dprintk("%s: getting locations for %s/%s\n",
3110ff80	327	__func__, parent->d_name.name, dentry->d_name.name);
54ceac45	328
f05d147f	329	err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
f7b422b1	330	dput(parent);
54ceac45 DH	331	if (err != 0 \|\|
54ceac45 DH	332	fs_locations->nlocations <= 0 \|\|
f7b422b1 DH	333	fs_locations->fs_path.ncomponents <= 0)
	334	goto out_free;
	335
f8ad9c4b	336	mnt = nfs_follow_referral(dentry, fs_locations);
f7b422b1 DH	337	out_free:
	338	__free_page(page);
	339	kfree(fs_locations);
	340	out:
3110ff80	341	dprintk("%s: done\n", __func__);
f7b422b1 DH	342	return mnt;
f7b422b1 DH	343	}