[linux-block.git] / fs / nfs / nfs4namespace.c

// SPDX-License-Identifier: GPL-2.0
/*
 * 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/nfs_mount.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/addr.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,
			      NFS_PATH_CANONICAL);
	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 net *net)
{
	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;
}

/**
 * nfs_find_best_sec - Find a security mechanism supported locally
 * @server: NFS server struct
 * @flavors: List of security tuples returned by SECINFO procedure
 *
 * Return an rpc client that uses the first security mechanism in
 * "flavors" that is locally supported.  The "flavors" array
 * is searched in the order returned from the server, per RFC 3530
 * recommendation and each flavor is checked for membership in the
 * sec= mount option list if it exists.
 *
 * Return -EPERM if no matching flavor is found in the array.
 *
 * Please call rpc_shutdown_client() when you are done with this rpc client.
 *
 */
static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
					  struct nfs_server *server,
					  struct nfs4_secinfo_flavors *flavors)
{
	rpc_authflavor_t pflavor;
	struct nfs4_secinfo4 *secinfo;
	unsigned int i;

	for (i = 0; i < flavors->num_flavors; i++) {
		secinfo = &flavors->flavors[i];

		switch (secinfo->flavor) {
		case RPC_AUTH_NULL:
		case RPC_AUTH_UNIX:
		case RPC_AUTH_GSS:
			pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
							&secinfo->flavor_info);
			/* does the pseudoflavor match a sec= mount opt? */
			if (pflavor != RPC_AUTH_MAXFLAVOR &&
			    nfs_auth_info_match(&server->auth_info, pflavor)) {
				struct rpc_clnt *new;
				struct rpc_cred *cred;

				/* Cloning creates an rpc_auth for the flavor */
				new = rpc_clone_client_set_auth(clnt, pflavor);
				if (IS_ERR(new))
					continue;
				/**
				* Check that the user actually can use the
				* flavor. This is mostly for RPC_AUTH_GSS
				* where cr_init obtains a gss context
				*/
				cred = rpcauth_lookupcred(new->cl_auth, 0);
				if (IS_ERR(cred)) {
					rpc_shutdown_client(new);
					continue;
				}
				put_rpccred(cred);
				return new;
			}
		}
	}
	return ERR_PTR(-EPERM);
}

/**
 * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
 * return an rpc_clnt that uses the best available security flavor with
 * respect to the secinfo flavor list and the sec= mount options.
 *
 * @clnt: RPC client to clone
 * @inode: directory inode
 * @name: lookup name
 *
 * Please call rpc_shutdown_client() when you are done with this rpc client.
 */
struct rpc_clnt *
nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
					const struct qstr *name)
{
	struct page *page;
	struct nfs4_secinfo_flavors *flavors;
	struct rpc_clnt *new;
	int err;

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

	flavors = page_address(page);

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

	new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);

out:
	put_page(page);
	return new;
}

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 net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
	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, net);
		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_submount(mountdata->dentry, &nfs4_referral_fs_type, 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 %pd2\n", __func__, dentry);

	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);
	return mnt;
}

/*
 * nfs_do_refmount - handle crossing a referral on server
 * @dentry - dentry of referral
 *
 */
static 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)); */
	page = alloc_page(GFP_KERNEL);
	if (page == NULL)
		return mnt;

	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 %pd2\n",
		__func__, dentry);

	err = nfs4_proc_fs_locations(client, d_inode(parent), &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);
	return mnt;
}

struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
			       struct nfs_fh *fh, struct nfs_fattr *fattr)
{
	rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
	struct dentry *parent = dget_parent(dentry);
	struct inode *dir = d_inode(parent);
	const struct qstr *name = &dentry->d_name;
	struct rpc_clnt *client;
	struct vfsmount *mnt;

	/* Look it up again to get its attributes and sec flavor */
	client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
	dput(parent);
	if (IS_ERR(client))
		return ERR_CAST(client);

	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
		mnt = nfs_do_refmount(client, dentry);
		goto out;
	}

	if (client->cl_auth->au_flavor != flavor)
		flavor = client->cl_auth->au_flavor;
	mnt = nfs_do_submount(dentry, fh, fattr, flavor);
out:
	rpc_shutdown_client(client);
	return mnt;
}

/*
 * Try one location from the fs_locations array.
 *
 * Returns zero on success, or a negative errno value.
 */
static int nfs4_try_replacing_one_location(struct nfs_server *server,
		char *page, char *page2,
		const struct nfs4_fs_location *location)
{
	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
	struct net *net = rpc_net_ns(server->client);
	struct sockaddr *sap;
	unsigned int s;
	size_t salen;
	int error;

	sap = kmalloc(addr_bufsize, GFP_KERNEL);
	if (sap == NULL)
		return -ENOMEM;

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

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

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

		salen = nfs_parse_server_name(buf->data, buf->len,
						sap, addr_bufsize, net);
		if (salen == 0)
			continue;
		rpc_set_port(sap, NFS_PORT);

		error = -ENOMEM;
		hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
		if (hostname == NULL)
			break;

		error = nfs4_update_server(server, hostname, sap, salen, net);
		kfree(hostname);
		if (error == 0)
			break;
	}

	kfree(sap);
	return error;
}

/**
 * nfs4_replace_transport - set up transport to destination server
 *
 * @server: export being migrated
 * @locations: fs_locations array
 *
 * Returns zero on success, or a negative errno value.
 *
 * The client tries all the entries in the "locations" array, in the
 * order returned by the server, until one works or the end of the
 * array is reached.
 */
int nfs4_replace_transport(struct nfs_server *server,
			   const struct nfs4_fs_locations *locations)
{
	char *page = NULL, *page2 = NULL;
	int loc, error;

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

	error = -ENOMEM;
	page = (char *) __get_free_page(GFP_USER);
	if (!page)
		goto out;
	page2 = (char *) __get_free_page(GFP_USER);
	if (!page2)
		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;

		error = nfs4_try_replacing_one_location(server, page,
							page2, location);
		if (error == 0)
			break;
	}

out:
	free_page((unsigned long)page);
	free_page((unsigned long)page2);
	return error;
}
Commit	Line	Data
b2441318	1	// SPDX-License-Identifier: GPL-2.0
f7b422b1 DH	2	/*
	3	* linux/fs/nfs/nfs4namespace.c
	4	*
	5	* Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
54ceac45	6	* - Modified by David Howells <dhowells@redhat.com>
f7b422b1 DH	7	*
	8	* NFSv4 namespace
	9	*/
	10
f7b422b1 DH	11	#include <linux/dcache.h>
	12	#include <linux/mount.h>
	13	#include <linux/namei.h>
	14	#include <linux/nfs_fs.h>
47040da3	15	#include <linux/nfs_mount.h>
5a0e3ad6	16	#include <linux/slab.h>
f7b422b1 DH	17	#include <linux/string.h>
f7b422b1 DH	18	#include <linux/sunrpc/clnt.h>
5976687a	19	#include <linux/sunrpc/addr.h>
f7b422b1 DH	20	#include <linux/vfs.h>
	21	#include <linux/inet.h>
	22	#include "internal.h"
c228fd3a	23	#include "nfs4_fs.h"
7d7ea882	24	#include "dns_resolve.h"
f7b422b1 DH	25
	26	#define NFSDBG_FACILITY NFSDBG_VFS
	27
	28	/*
ef95d31e TM	29	* Convert the NFSv4 pathname components into a standard posix path.
	30	*
	31	* Note that the resulting string will be placed at the end of the buffer
f7b422b1	32	*/
509de811	33	static inline char nfs4_pathname_string(const struct nfs4_pathname pathname,
f7b422b1 DH	34	char *buffer, ssize_t buflen)
	35	{
	36	char *end = buffer + buflen;
	37	int n;
	38
	39	*--end = '\0';
	40	buflen--;
	41
	42	n = pathname->ncomponents;
	43	while (--n >= 0) {
509de811	44	const struct nfs4_string *component = &pathname->components[n];
f7b422b1 DH	45	buflen -= component->len + 1;
	46	if (buflen < 0)
	47	goto Elong;
	48	end -= component->len;
	49	memcpy(end, component->data, component->len);
	50	*--end = '/';
	51	}
	52	return end;
	53	Elong:
	54	return ERR_PTR(-ENAMETOOLONG);
	55	}
	56
1aba1567 WAA	57	/*
	58	* return the path component of "<server>:<path>"
	59	* nfspath - the "<server>:<path>" string
	60	* end - one past the last char that could contain "<server>:"
	61	* returns NULL on failure
	62	*/
	63	static char nfs_path_component(const char nfspath, const char *end)
	64	{
	65	char *p;
	66
	67	if (*nfspath == '[') {
	68	/* parse [] escaped IPv6 addrs */
	69	p = strchr(nfspath, ']');
	70	if (p != NULL && ++p < end && *p == ':')
	71	return p + 1;
	72	} else {
	73	/* otherwise split on first colon */
	74	p = strchr(nfspath, ':');
	75	if (p != NULL && p < end)
	76	return p + 1;
	77	}
	78	return NULL;
	79	}
	80
54ceac45 DH	81	/*
	82	* Determine the mount path as a string
	83	*/
b514f872	84	static char nfs4_path(struct dentry dentry, char *buffer, ssize_t buflen)
54ceac45	85	{
b514f872	86	char *limit;
97a54868 BH	87	char *path = nfs_path(&limit, dentry, buffer, buflen,
97a54868 BH	88	NFS_PATH_CANONICAL);
b514f872	89	if (!IS_ERR(path)) {
1aba1567 WAA	90	char *path_component = nfs_path_component(path, limit);
	91	if (path_component)
	92	return path_component;
b514f872 AV	93	}
b514f872 AV	94	return path;
54ceac45 DH	95	}
	96
	97	/*
	98	* Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
	99	* believe to be the server path to this dentry
	100	*/
b514f872	101	static int nfs4_validate_fspath(struct dentry *dentry,
54ceac45 DH	102	const struct nfs4_fs_locations *locations,
	103	char page, char page2)
	104	{
	105	const char path, fs_path;
	106
b514f872	107	path = nfs4_path(dentry, page, PAGE_SIZE);
54ceac45 DH	108	if (IS_ERR(path))
	109	return PTR_ERR(path);
	110
	111	fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
	112	if (IS_ERR(fs_path))
	113	return PTR_ERR(fs_path);
	114
	115	if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
	116	dprintk("%s: path %s does not begin with fsroot %s\n",
3110ff80	117	__func__, path, fs_path);
54ceac45 DH	118	return -ENOENT;
	119	}
	120
	121	return 0;
	122	}
	123
7d7ea882	124	static size_t nfs_parse_server_name(char *string, size_t len,
292f503c	125	struct sockaddr sa, size_t salen, struct net net)
7d7ea882 TM	126	{
	127	ssize_t ret;
	128
33faaa38	129	ret = rpc_pton(net, string, len, sa, salen);
7d7ea882	130	if (ret == 0) {
33faaa38	131	ret = nfs_dns_resolve_name(net, string, len, sa, salen);
7d7ea882 TM	132	if (ret < 0)
	133	ret = 0;
	134	}
	135	return ret;
	136	}
	137
9568c5e9 CL	138	/**
9568c5e9 CL	139	* nfs_find_best_sec - Find a security mechanism supported locally
4d4b69dd	140	* @server: NFS server struct
9568c5e9 CL	141	* @flavors: List of security tuples returned by SECINFO procedure
9568c5e9 CL	142	*
66b06860 AA	143	* Return an rpc client that uses the first security mechanism in
66b06860 AA	144	* "flavors" that is locally supported. The "flavors" array
9568c5e9	145	* is searched in the order returned from the server, per RFC 3530
66b06860 AA	146	* recommendation and each flavor is checked for membership in the
66b06860 AA	147	* sec= mount option list if it exists.
8445cd35 AA	148	*
8445cd35 AA	149	* Return -EPERM if no matching flavor is found in the array.
66b06860 AA	150	*
	151	* Please call rpc_shutdown_client() when you are done with this rpc client.
	152	*
9568c5e9	153	*/
66b06860 AA	154	static struct rpc_clnt nfs_find_best_sec(struct rpc_clnt clnt,
66b06860 AA	155	struct nfs_server *server,
4d4b69dd	156	struct nfs4_secinfo_flavors *flavors)
2671bfc3	157	{
66b06860	158	rpc_authflavor_t pflavor;
9568c5e9	159	struct nfs4_secinfo4 *secinfo;
fb15b26f	160	unsigned int i;
2671bfc3 BS	161
2671bfc3 BS	162	for (i = 0; i < flavors->num_flavors; i++) {
9568c5e9 CL	163	secinfo = &flavors->flavors[i];
	164
	165	switch (secinfo->flavor) {
	166	case RPC_AUTH_NULL:
	167	case RPC_AUTH_UNIX:
	168	case RPC_AUTH_GSS:
66b06860	169	pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
9568c5e9	170	&secinfo->flavor_info);
66b06860 AA	171	/* does the pseudoflavor match a sec= mount opt? */
	172	if (pflavor != RPC_AUTH_MAXFLAVOR &&
	173	nfs_auth_info_match(&server->auth_info, pflavor)) {
	174	struct rpc_clnt *new;
	175	struct rpc_cred *cred;
	176
	177	/* Cloning creates an rpc_auth for the flavor */
	178	new = rpc_clone_client_set_auth(clnt, pflavor);
	179	if (IS_ERR(new))
	180	continue;
	181	/**
	182	* Check that the user actually can use the
	183	* flavor. This is mostly for RPC_AUTH_GSS
	184	* where cr_init obtains a gss context
	185	*/
	186	cred = rpcauth_lookupcred(new->cl_auth, 0);
	187	if (IS_ERR(cred)) {
	188	rpc_shutdown_client(new);
	189	continue;
	190	}
	191	put_rpccred(cred);
	192	return new;
	193	}
2671bfc3 BS	194	}
2671bfc3 BS	195	}
66b06860	196	return ERR_PTR(-EPERM);
2671bfc3 BS	197	}
2671bfc3 BS	198
66b06860 AA	199	/**
	200	* nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
	201	* return an rpc_clnt that uses the best available security flavor with
	202	* respect to the secinfo flavor list and the sec= mount options.
	203	*
	204	* @clnt: RPC client to clone
	205	* @inode: directory inode
	206	* @name: lookup name
	207	*
	208	* Please call rpc_shutdown_client() when you are done with this rpc client.
	209	*/
	210	struct rpc_clnt *
	211	nfs4_negotiate_security(struct rpc_clnt clnt, struct inode inode,
beffb8fe	212	const struct qstr *name)
72de53ec BS	213	{
	214	struct page *page;
	215	struct nfs4_secinfo_flavors *flavors;
66b06860	216	struct rpc_clnt *new;
72de53ec BS	217	int err;
	218
	219	page = alloc_page(GFP_KERNEL);
	220	if (!page)
66b06860 AA	221	return ERR_PTR(-ENOMEM);
66b06860 AA	222
72de53ec BS	223	flavors = page_address(page);
	224
	225	err = nfs4_proc_secinfo(inode, name, flavors);
	226	if (err < 0) {
66b06860	227	new = ERR_PTR(err);
72de53ec BS	228	goto out;
	229	}
	230
66b06860	231	new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
72de53ec BS	232
	233	out:
	234	put_page(page);
66b06860	235	return new;
72de53ec BS	236	}
72de53ec BS	237
4ada29d5 BF	238	static struct vfsmount try_location(struct nfs_clone_mount mountdata,
	239	char page, char page2,
	240	const struct nfs4_fs_location *location)
	241	{
364d015e	242	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
292f503c	243	struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
4ada29d5 BF	244	struct vfsmount *mnt = ERR_PTR(-ENOENT);
4ada29d5 BF	245	char *mnt_path;
ef95d31e	246	unsigned int maxbuflen;
460cdbc8	247	unsigned int s;
4ada29d5 BF	248
	249	mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
	250	if (IS_ERR(mnt_path))
517be09d	251	return ERR_CAST(mnt_path);
4ada29d5	252	mountdata->mnt_path = mnt_path;
ef95d31e	253	maxbuflen = mnt_path - 1 - page2;
4ada29d5	254
364d015e TM	255	mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
	256	if (mountdata->addr == NULL)
	257	return ERR_PTR(-ENOMEM);
	258
460cdbc8	259	for (s = 0; s < location->nservers; s++) {
ea31a443	260	const struct nfs4_string *buf = &location->servers[s];
4ada29d5	261
ef95d31e	262	if (buf->len <= 0 \|\| buf->len >= maxbuflen)
4ada29d5	263	continue;
4ada29d5	264
ea31a443 BF	265	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
ea31a443 BF	266	continue;
517be09d TM	267
517be09d TM	268	mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
292f503c	269	mountdata->addr, addr_bufsize, net);
53a0b9c4	270	if (mountdata->addrlen == 0)
ea31a443	271	continue;
517be09d	272
ec6ee612	273	rpc_set_port(mountdata->addr, NFS_PORT);
ea31a443	274
ef95d31e TM	275	memcpy(page2, buf->data, buf->len);
ef95d31e TM	276	page2[buf->len] = '\0';
ea31a443	277	mountdata->hostname = page2;
4ada29d5 BF	278
	279	snprintf(page, PAGE_SIZE, "%s:%s",
	280	mountdata->hostname,
	281	mountdata->mnt_path);
	282
93faccbb	283	mnt = vfs_submount(mountdata->dentry, &nfs4_referral_fs_type, page, mountdata);
4ada29d5 BF	284	if (!IS_ERR(mnt))
4ada29d5 BF	285	break;
4ada29d5	286	}
364d015e	287	kfree(mountdata->addr);
4ada29d5 BF	288	return mnt;
	289	}
	290
f7b422b1 DH	291	/**
f7b422b1 DH	292	* nfs_follow_referral - set up mountpoint when hitting a referral on moved error
f7b422b1	293	* @dentry - parent directory
3f43c666	294	* @locations - array of NFSv4 server location information
f7b422b1 DH	295	*
f7b422b1 DH	296	*/
f8ad9c4b	297	static struct vfsmount nfs_follow_referral(struct dentry dentry,
509de811	298	const struct nfs4_fs_locations *locations)
f7b422b1 DH	299	{
	300	struct vfsmount *mnt = ERR_PTR(-ENOENT);
	301	struct nfs_clone_mount mountdata = {
f8ad9c4b	302	.sb = dentry->d_sb,
f7b422b1	303	.dentry = dentry,
f8ad9c4b	304	.authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
f7b422b1	305	};
54ceac45	306	char page = NULL, page2 = NULL;
3f43c666	307	int loc, error;
f7b422b1 DH	308
	309	if (locations == NULL \|\| locations->nlocations <= 0)
	310	goto out;
	311
6de1472f	312	dprintk("%s: referral at %pd2\n", __func__, dentry);
f7b422b1	313
f7b422b1	314	page = (char *) __get_free_page(GFP_USER);
54ceac45	315	if (!page)
f7b422b1	316	goto out;
54ceac45	317
f7b422b1	318	page2 = (char *) __get_free_page(GFP_USER);
54ceac45	319	if (!page2)
f7b422b1 DH	320	goto out;
f7b422b1 DH	321
54ceac45	322	/* Ensure fs path is a prefix of current dentry path */
b514f872	323	error = nfs4_validate_fspath(dentry, locations, page, page2);
54ceac45 DH	324	if (error < 0) {
	325	mnt = ERR_PTR(error);
	326	goto out;
f7b422b1 DH	327	}
f7b422b1 DH	328
460cdbc8	329	for (loc = 0; loc < locations->nlocations; loc++) {
509de811	330	const struct nfs4_fs_location *location = &locations->locations[loc];
f7b422b1 DH	331
f7b422b1 DH	332	if (location == NULL \|\| location->nservers <= 0 \|\|
460cdbc8	333	location->rootpath.ncomponents == 0)
f7b422b1	334	continue;
f7b422b1	335
4ada29d5 BF	336	mnt = try_location(&mountdata, page, page2, location);
	337	if (!IS_ERR(mnt))
	338	break;
f7b422b1 DH	339	}
f7b422b1 DH	340
f7b422b1	341	out:
54ceac45 DH	342	free_page((unsigned long) page);
54ceac45 DH	343	free_page((unsigned long) page2);
f7b422b1 DH	344	return mnt;
	345	}
	346
	347	/*
	348	* nfs_do_refmount - handle crossing a referral on server
	349	* @dentry - dentry of referral
f7b422b1 DH	350	*
f7b422b1 DH	351	*/
281cad46	352	static struct vfsmount nfs_do_refmount(struct rpc_clnt client, struct dentry *dentry)
f7b422b1	353	{
54ceac45	354	struct vfsmount *mnt = ERR_PTR(-ENOMEM);
f7b422b1 DH	355	struct dentry *parent;
	356	struct nfs4_fs_locations *fs_locations = NULL;
	357	struct page *page;
	358	int err;
	359
	360	/* BUG_ON(IS_ROOT(dentry)); */
f7b422b1 DH	361	page = alloc_page(GFP_KERNEL);
f7b422b1 DH	362	if (page == NULL)
3183783b	363	return mnt;
f7b422b1 DH	364
	365	fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
	366	if (fs_locations == NULL)
	367	goto out_free;
	368
	369	/* Get locations */
54ceac45 DH	370	mnt = ERR_PTR(-ENOENT);
54ceac45 DH	371
f7b422b1	372	parent = dget_parent(dentry);
6de1472f AV	373	dprintk("%s: getting locations for %pd2\n",
6de1472f AV	374	__func__, dentry);
54ceac45	375
2b0143b5	376	err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page);
f7b422b1	377	dput(parent);
54ceac45 DH	378	if (err != 0 \|\|
54ceac45 DH	379	fs_locations->nlocations <= 0 \|\|
f7b422b1 DH	380	fs_locations->fs_path.ncomponents <= 0)
	381	goto out_free;
	382
f8ad9c4b	383	mnt = nfs_follow_referral(dentry, fs_locations);
f7b422b1 DH	384	out_free:
	385	__free_page(page);
	386	kfree(fs_locations);
f7b422b1 DH	387	return mnt;
f7b422b1 DH	388	}
281cad46 BS	389
	390	struct vfsmount nfs4_submount(struct nfs_server server, struct dentry *dentry,
	391	struct nfs_fh fh, struct nfs_fattr fattr)
	392	{
47040da3	393	rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
281cad46	394	struct dentry *parent = dget_parent(dentry);
2b0143b5	395	struct inode *dir = d_inode(parent);
beffb8fe	396	const struct qstr *name = &dentry->d_name;
281cad46 BS	397	struct rpc_clnt *client;
	398	struct vfsmount *mnt;
	399
	400	/* Look it up again to get its attributes and sec flavor */
47040da3	401	client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
281cad46 BS	402	dput(parent);
	403	if (IS_ERR(client))
	404	return ERR_CAST(client);
	405
47040da3	406	if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
281cad46	407	mnt = nfs_do_refmount(client, dentry);
47040da3 TM	408	goto out;
47040da3 TM	409	}
281cad46	410
47040da3 TM	411	if (client->cl_auth->au_flavor != flavor)
47040da3 TM	412	flavor = client->cl_auth->au_flavor;
47040da3 TM	413	mnt = nfs_do_submount(dentry, fh, fattr, flavor);
47040da3 TM	414	out:
281cad46 BS	415	rpc_shutdown_client(client);
	416	return mnt;
	417	}
800c06a5 CL	418
	419	/*
	420	* Try one location from the fs_locations array.
	421	*
	422	* Returns zero on success, or a negative errno value.
	423	*/
	424	static int nfs4_try_replacing_one_location(struct nfs_server *server,
	425	char page, char page2,
	426	const struct nfs4_fs_location *location)
	427	{
	428	const size_t addr_bufsize = sizeof(struct sockaddr_storage);
292f503c	429	struct net *net = rpc_net_ns(server->client);
800c06a5 CL	430	struct sockaddr *sap;
	431	unsigned int s;
	432	size_t salen;
	433	int error;
	434
	435	sap = kmalloc(addr_bufsize, GFP_KERNEL);
	436	if (sap == NULL)
	437	return -ENOMEM;
	438
	439	error = -ENOENT;
	440	for (s = 0; s < location->nservers; s++) {
	441	const struct nfs4_string *buf = &location->servers[s];
	442	char *hostname;
	443
	444	if (buf->len <= 0 \|\| buf->len > PAGE_SIZE)
	445	continue;
	446
	447	if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
	448	continue;
	449
	450	salen = nfs_parse_server_name(buf->data, buf->len,
292f503c	451	sap, addr_bufsize, net);
800c06a5 CL	452	if (salen == 0)
	453	continue;
	454	rpc_set_port(sap, NFS_PORT);
	455
	456	error = -ENOMEM;
	457	hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
	458	if (hostname == NULL)
	459	break;
	460
292f503c	461	error = nfs4_update_server(server, hostname, sap, salen, net);
800c06a5 CL	462	kfree(hostname);
	463	if (error == 0)
	464	break;
	465	}
	466
	467	kfree(sap);
	468	return error;
	469	}
	470
	471	/**
	472	* nfs4_replace_transport - set up transport to destination server
	473	*
	474	* @server: export being migrated
	475	* @locations: fs_locations array
	476	*
	477	* Returns zero on success, or a negative errno value.
	478	*
	479	* The client tries all the entries in the "locations" array, in the
	480	* order returned by the server, until one works or the end of the
	481	* array is reached.
	482	*/
	483	int nfs4_replace_transport(struct nfs_server *server,
	484	const struct nfs4_fs_locations *locations)
	485	{
	486	char page = NULL, page2 = NULL;
	487	int loc, error;
	488
	489	error = -ENOENT;
	490	if (locations == NULL \|\| locations->nlocations <= 0)
	491	goto out;
	492
	493	error = -ENOMEM;
	494	page = (char *) __get_free_page(GFP_USER);
	495	if (!page)
	496	goto out;
	497	page2 = (char *) __get_free_page(GFP_USER);
	498	if (!page2)
	499	goto out;
	500
	501	for (loc = 0; loc < locations->nlocations; loc++) {
	502	const struct nfs4_fs_location *location =
	503	&locations->locations[loc];
	504
	505	if (location == NULL \|\| location->nservers <= 0 \|\|
	506	location->rootpath.ncomponents == 0)
	507	continue;
	508
	509	error = nfs4_try_replacing_one_location(server, page,
	510	page2, location);
	511	if (error == 0)
	512	break;
	513	}
	514
	515	out:
	516	free_page((unsigned long)page);
	517	free_page((unsigned long)page2);
	518	return error;
	519	}