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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * linux/fs/nfs/nfs4namespace.c
4 *
5 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
6 * - Modified by David Howells <dhowells@redhat.com>
7 *
8 * NFSv4 namespace
9 */
10
11#include <linux/module.h>
12#include <linux/dcache.h>
13#include <linux/mount.h>
14#include <linux/namei.h>
15#include <linux/nfs_fs.h>
16#include <linux/nfs_mount.h>
17#include <linux/slab.h>
18#include <linux/string.h>
19#include <linux/sunrpc/clnt.h>
20#include <linux/sunrpc/addr.h>
21#include <linux/vfs.h>
22#include <linux/inet.h>
23#include "internal.h"
24#include "nfs4_fs.h"
25#include "nfs.h"
26#include "dns_resolve.h"
27
28#define NFSDBG_FACILITY NFSDBG_VFS
29
30/*
31 * Work out the length that an NFSv4 path would render to as a standard posix
32 * path, with a leading slash but no terminating slash.
33 */
34static ssize_t nfs4_pathname_len(const struct nfs4_pathname *pathname)
35{
36 ssize_t len = 0;
37 int i;
38
39 for (i = 0; i < pathname->ncomponents; i++) {
40 const struct nfs4_string *component = &pathname->components[i];
41
42 if (component->len > NAME_MAX)
43 goto too_long;
44 len += 1 + component->len; /* Adding "/foo" */
45 if (len > PATH_MAX)
46 goto too_long;
47 }
48 return len;
49
50too_long:
51 return -ENAMETOOLONG;
52}
53
54/*
55 * Convert the NFSv4 pathname components into a standard posix path.
56 */
57static char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
58 unsigned short *_len)
59{
60 ssize_t len;
61 char *buf, *p;
62 int i;
63
64 len = nfs4_pathname_len(pathname);
65 if (len < 0)
66 return ERR_PTR(len);
67 *_len = len;
68
69 p = buf = kmalloc(len + 1, GFP_KERNEL);
70 if (!buf)
71 return ERR_PTR(-ENOMEM);
72
73 for (i = 0; i < pathname->ncomponents; i++) {
74 const struct nfs4_string *component = &pathname->components[i];
75
76 *p++ = '/';
77 memcpy(p, component->data, component->len);
78 p += component->len;
79 }
80
81 *p = 0;
82 return buf;
83}
84
85/*
86 * return the path component of "<server>:<path>"
87 * nfspath - the "<server>:<path>" string
88 * end - one past the last char that could contain "<server>:"
89 * returns NULL on failure
90 */
91static char *nfs_path_component(const char *nfspath, const char *end)
92{
93 char *p;
94
95 if (*nfspath == '[') {
96 /* parse [] escaped IPv6 addrs */
97 p = strchr(nfspath, ']');
98 if (p != NULL && ++p < end && *p == ':')
99 return p + 1;
100 } else {
101 /* otherwise split on first colon */
102 p = strchr(nfspath, ':');
103 if (p != NULL && p < end)
104 return p + 1;
105 }
106 return NULL;
107}
108
109/*
110 * Determine the mount path as a string
111 */
112static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
113{
114 char *limit;
115 char *path = nfs_path(&limit, dentry, buffer, buflen,
116 NFS_PATH_CANONICAL);
117 if (!IS_ERR(path)) {
118 char *path_component = nfs_path_component(path, limit);
119 if (path_component)
120 return path_component;
121 }
122 return path;
123}
124
125/*
126 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
127 * believe to be the server path to this dentry
128 */
129static int nfs4_validate_fspath(struct dentry *dentry,
130 const struct nfs4_fs_locations *locations,
131 struct nfs_fs_context *ctx)
132{
133 const char *path;
134 char *fs_path;
135 unsigned short len;
136 char *buf;
137 int n;
138
139 buf = kmalloc(4096, GFP_KERNEL);
140 if (!buf)
141 return -ENOMEM;
142
143 path = nfs4_path(dentry, buf, 4096);
144 if (IS_ERR(path)) {
145 kfree(buf);
146 return PTR_ERR(path);
147 }
148
149 fs_path = nfs4_pathname_string(&locations->fs_path, &len);
150 if (IS_ERR(fs_path)) {
151 kfree(buf);
152 return PTR_ERR(fs_path);
153 }
154
155 n = strncmp(path, fs_path, len);
156 kfree(buf);
157 kfree(fs_path);
158 if (n != 0) {
159 dprintk("%s: path %s does not begin with fsroot %s\n",
160 __func__, path, ctx->nfs_server.export_path);
161 return -ENOENT;
162 }
163
164 return 0;
165}
166
167static size_t nfs_parse_server_name(char *string, size_t len,
168 struct sockaddr *sa, size_t salen, struct net *net)
169{
170 ssize_t ret;
171
172 ret = rpc_pton(net, string, len, sa, salen);
173 if (ret == 0) {
174 ret = nfs_dns_resolve_name(net, string, len, sa, salen);
175 if (ret < 0)
176 ret = 0;
177 }
178 return ret;
179}
180
181/**
182 * nfs_find_best_sec - Find a security mechanism supported locally
183 * @clnt: pointer to rpc_clnt
184 * @server: NFS server struct
185 * @flavors: List of security tuples returned by SECINFO procedure
186 *
187 * Return an rpc client that uses the first security mechanism in
188 * "flavors" that is locally supported. The "flavors" array
189 * is searched in the order returned from the server, per RFC 3530
190 * recommendation and each flavor is checked for membership in the
191 * sec= mount option list if it exists.
192 *
193 * Return -EPERM if no matching flavor is found in the array.
194 *
195 * Please call rpc_shutdown_client() when you are done with this rpc client.
196 *
197 */
198static struct rpc_clnt *nfs_find_best_sec(struct rpc_clnt *clnt,
199 struct nfs_server *server,
200 struct nfs4_secinfo_flavors *flavors)
201{
202 rpc_authflavor_t pflavor;
203 struct nfs4_secinfo4 *secinfo;
204 unsigned int i;
205
206 for (i = 0; i < flavors->num_flavors; i++) {
207 secinfo = &flavors->flavors[i];
208
209 switch (secinfo->flavor) {
210 case RPC_AUTH_NULL:
211 case RPC_AUTH_UNIX:
212 case RPC_AUTH_GSS:
213 pflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
214 &secinfo->flavor_info);
215 /* does the pseudoflavor match a sec= mount opt? */
216 if (pflavor != RPC_AUTH_MAXFLAVOR &&
217 nfs_auth_info_match(&server->auth_info, pflavor)) {
218 struct rpc_clnt *new;
219 struct rpc_cred *cred;
220
221 /* Cloning creates an rpc_auth for the flavor */
222 new = rpc_clone_client_set_auth(clnt, pflavor);
223 if (IS_ERR(new))
224 continue;
225 /**
226 * Check that the user actually can use the
227 * flavor. This is mostly for RPC_AUTH_GSS
228 * where cr_init obtains a gss context
229 */
230 cred = rpcauth_lookupcred(new->cl_auth, 0);
231 if (IS_ERR(cred)) {
232 rpc_shutdown_client(new);
233 continue;
234 }
235 put_rpccred(cred);
236 return new;
237 }
238 }
239 }
240 return ERR_PTR(-EPERM);
241}
242
243/**
244 * nfs4_negotiate_security - in response to an NFS4ERR_WRONGSEC on lookup,
245 * return an rpc_clnt that uses the best available security flavor with
246 * respect to the secinfo flavor list and the sec= mount options.
247 *
248 * @clnt: RPC client to clone
249 * @inode: directory inode
250 * @name: lookup name
251 *
252 * Please call rpc_shutdown_client() when you are done with this rpc client.
253 */
254struct rpc_clnt *
255nfs4_negotiate_security(struct rpc_clnt *clnt, struct inode *inode,
256 const struct qstr *name)
257{
258 struct page *page;
259 struct nfs4_secinfo_flavors *flavors;
260 struct rpc_clnt *new;
261 int err;
262
263 page = alloc_page(GFP_KERNEL);
264 if (!page)
265 return ERR_PTR(-ENOMEM);
266
267 flavors = page_address(page);
268
269 err = nfs4_proc_secinfo(inode, name, flavors);
270 if (err < 0) {
271 new = ERR_PTR(err);
272 goto out;
273 }
274
275 new = nfs_find_best_sec(clnt, NFS_SERVER(inode), flavors);
276
277out:
278 put_page(page);
279 return new;
280}
281
282static int try_location(struct fs_context *fc,
283 const struct nfs4_fs_location *location)
284{
285 struct nfs_fs_context *ctx = nfs_fc2context(fc);
286 unsigned int len, s;
287 char *export_path, *source, *p;
288 int ret = -ENOENT;
289
290 /* Allocate a buffer big enough to hold any of the hostnames plus a
291 * terminating char and also a buffer big enough to hold the hostname
292 * plus a colon plus the path.
293 */
294 len = 0;
295 for (s = 0; s < location->nservers; s++) {
296 const struct nfs4_string *buf = &location->servers[s];
297 if (buf->len > len)
298 len = buf->len;
299 }
300
301 kfree(ctx->nfs_server.hostname);
302 ctx->nfs_server.hostname = kmalloc(len + 1, GFP_KERNEL);
303 if (!ctx->nfs_server.hostname)
304 return -ENOMEM;
305
306 export_path = nfs4_pathname_string(&location->rootpath,
307 &ctx->nfs_server.export_path_len);
308 if (IS_ERR(export_path))
309 return PTR_ERR(export_path);
310
311 kfree(ctx->nfs_server.export_path);
312 ctx->nfs_server.export_path = export_path;
313
314 source = kmalloc(len + 1 + ctx->nfs_server.export_path_len + 1,
315 GFP_KERNEL);
316 if (!source)
317 return -ENOMEM;
318
319 kfree(fc->source);
320 fc->source = source;
321 for (s = 0; s < location->nservers; s++) {
322 const struct nfs4_string *buf = &location->servers[s];
323
324 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
325 continue;
326
327 ctx->nfs_server.addrlen =
328 nfs_parse_server_name(buf->data, buf->len,
329 &ctx->nfs_server.address,
330 sizeof(ctx->nfs_server._address),
331 fc->net_ns);
332 if (ctx->nfs_server.addrlen == 0)
333 continue;
334
335 rpc_set_port(&ctx->nfs_server.address, NFS_PORT);
336
337 memcpy(ctx->nfs_server.hostname, buf->data, buf->len);
338 ctx->nfs_server.hostname[buf->len] = '\0';
339
340 p = source;
341 memcpy(p, buf->data, buf->len);
342 p += buf->len;
343 *p++ = ':';
344 memcpy(p, ctx->nfs_server.export_path, ctx->nfs_server.export_path_len);
345 p += ctx->nfs_server.export_path_len;
346 *p = 0;
347
348 ret = nfs4_get_referral_tree(fc);
349 if (ret == 0)
350 return 0;
351 }
352
353 return ret;
354}
355
356/**
357 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
358 * @fc: pointer to struct nfs_fs_context
359 * @locations: array of NFSv4 server location information
360 *
361 */
362static int nfs_follow_referral(struct fs_context *fc,
363 const struct nfs4_fs_locations *locations)
364{
365 struct nfs_fs_context *ctx = nfs_fc2context(fc);
366 int loc, error;
367
368 if (locations == NULL || locations->nlocations <= 0)
369 return -ENOENT;
370
371 dprintk("%s: referral at %pd2\n", __func__, ctx->clone_data.dentry);
372
373 /* Ensure fs path is a prefix of current dentry path */
374 error = nfs4_validate_fspath(ctx->clone_data.dentry, locations, ctx);
375 if (error < 0)
376 return error;
377
378 error = -ENOENT;
379 for (loc = 0; loc < locations->nlocations; loc++) {
380 const struct nfs4_fs_location *location = &locations->locations[loc];
381
382 if (location == NULL || location->nservers <= 0 ||
383 location->rootpath.ncomponents == 0)
384 continue;
385
386 error = try_location(fc, location);
387 if (error == 0)
388 return 0;
389 }
390
391 return error;
392}
393
394/*
395 * nfs_do_refmount - handle crossing a referral on server
396 * @dentry - dentry of referral
397 *
398 */
399static int nfs_do_refmount(struct fs_context *fc, struct rpc_clnt *client)
400{
401 struct nfs_fs_context *ctx = nfs_fc2context(fc);
402 struct dentry *dentry, *parent;
403 struct nfs4_fs_locations *fs_locations = NULL;
404 struct page *page;
405 int err = -ENOMEM;
406
407 /* BUG_ON(IS_ROOT(dentry)); */
408 page = alloc_page(GFP_KERNEL);
409 if (!page)
410 return -ENOMEM;
411
412 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
413 if (!fs_locations)
414 goto out_free;
415
416 /* Get locations */
417 dentry = ctx->clone_data.dentry;
418 parent = dget_parent(dentry);
419 dprintk("%s: getting locations for %pd2\n",
420 __func__, dentry);
421
422 err = nfs4_proc_fs_locations(client, d_inode(parent), &dentry->d_name, fs_locations, page);
423 dput(parent);
424 if (err != 0)
425 goto out_free_2;
426
427 err = -ENOENT;
428 if (fs_locations->nlocations <= 0 ||
429 fs_locations->fs_path.ncomponents <= 0)
430 goto out_free_2;
431
432 err = nfs_follow_referral(fc, fs_locations);
433out_free_2:
434 kfree(fs_locations);
435out_free:
436 __free_page(page);
437 return err;
438}
439
440int nfs4_submount(struct fs_context *fc, struct nfs_server *server)
441{
442 struct nfs_fs_context *ctx = nfs_fc2context(fc);
443 struct dentry *dentry = ctx->clone_data.dentry;
444 struct dentry *parent = dget_parent(dentry);
445 struct inode *dir = d_inode(parent);
446 struct rpc_clnt *client;
447 int ret;
448
449 /* Look it up again to get its attributes and sec flavor */
450 client = nfs4_proc_lookup_mountpoint(dir, dentry, ctx->mntfh,
451 ctx->clone_data.fattr);
452 dput(parent);
453 if (IS_ERR(client))
454 return PTR_ERR(client);
455
456 ctx->selected_flavor = client->cl_auth->au_flavor;
457 if (ctx->clone_data.fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
458 ret = nfs_do_refmount(fc, client);
459 } else {
460 ret = nfs_do_submount(fc);
461 }
462
463 rpc_shutdown_client(client);
464 return ret;
465}
466
467/*
468 * Try one location from the fs_locations array.
469 *
470 * Returns zero on success, or a negative errno value.
471 */
472static int nfs4_try_replacing_one_location(struct nfs_server *server,
473 char *page, char *page2,
474 const struct nfs4_fs_location *location)
475{
476 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
477 struct net *net = rpc_net_ns(server->client);
478 struct sockaddr *sap;
479 unsigned int s;
480 size_t salen;
481 int error;
482
483 sap = kmalloc(addr_bufsize, GFP_KERNEL);
484 if (sap == NULL)
485 return -ENOMEM;
486
487 error = -ENOENT;
488 for (s = 0; s < location->nservers; s++) {
489 const struct nfs4_string *buf = &location->servers[s];
490 char *hostname;
491
492 if (buf->len <= 0 || buf->len > PAGE_SIZE)
493 continue;
494
495 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
496 continue;
497
498 salen = nfs_parse_server_name(buf->data, buf->len,
499 sap, addr_bufsize, net);
500 if (salen == 0)
501 continue;
502 rpc_set_port(sap, NFS_PORT);
503
504 error = -ENOMEM;
505 hostname = kmemdup_nul(buf->data, buf->len, GFP_KERNEL);
506 if (hostname == NULL)
507 break;
508
509 error = nfs4_update_server(server, hostname, sap, salen, net);
510 kfree(hostname);
511 if (error == 0)
512 break;
513 }
514
515 kfree(sap);
516 return error;
517}
518
519/**
520 * nfs4_replace_transport - set up transport to destination server
521 *
522 * @server: export being migrated
523 * @locations: fs_locations array
524 *
525 * Returns zero on success, or a negative errno value.
526 *
527 * The client tries all the entries in the "locations" array, in the
528 * order returned by the server, until one works or the end of the
529 * array is reached.
530 */
531int nfs4_replace_transport(struct nfs_server *server,
532 const struct nfs4_fs_locations *locations)
533{
534 char *page = NULL, *page2 = NULL;
535 int loc, error;
536
537 error = -ENOENT;
538 if (locations == NULL || locations->nlocations <= 0)
539 goto out;
540
541 error = -ENOMEM;
542 page = (char *) __get_free_page(GFP_USER);
543 if (!page)
544 goto out;
545 page2 = (char *) __get_free_page(GFP_USER);
546 if (!page2)
547 goto out;
548
549 for (loc = 0; loc < locations->nlocations; loc++) {
550 const struct nfs4_fs_location *location =
551 &locations->locations[loc];
552
553 if (location == NULL || location->nservers <= 0 ||
554 location->rootpath.ncomponents == 0)
555 continue;
556
557 error = nfs4_try_replacing_one_location(server, page,
558 page2, location);
559 if (error == 0)
560 break;
561 }
562
563out:
564 free_page((unsigned long)page);
565 free_page((unsigned long)page2);
566 return error;
567}
1/*
2 * linux/fs/nfs/nfs4namespace.c
3 *
4 * Copyright (C) 2005 Trond Myklebust <Trond.Myklebust@netapp.com>
5 * - Modified by David Howells <dhowells@redhat.com>
6 *
7 * NFSv4 namespace
8 */
9
10#include <linux/dcache.h>
11#include <linux/mount.h>
12#include <linux/namei.h>
13#include <linux/nfs_fs.h>
14#include <linux/nfs_mount.h>
15#include <linux/slab.h>
16#include <linux/string.h>
17#include <linux/sunrpc/clnt.h>
18#include <linux/sunrpc/addr.h>
19#include <linux/vfs.h>
20#include <linux/inet.h>
21#include "internal.h"
22#include "nfs4_fs.h"
23#include "dns_resolve.h"
24
25#define NFSDBG_FACILITY NFSDBG_VFS
26
27/*
28 * Convert the NFSv4 pathname components into a standard posix path.
29 *
30 * Note that the resulting string will be placed at the end of the buffer
31 */
32static inline char *nfs4_pathname_string(const struct nfs4_pathname *pathname,
33 char *buffer, ssize_t buflen)
34{
35 char *end = buffer + buflen;
36 int n;
37
38 *--end = '\0';
39 buflen--;
40
41 n = pathname->ncomponents;
42 while (--n >= 0) {
43 const struct nfs4_string *component = &pathname->components[n];
44 buflen -= component->len + 1;
45 if (buflen < 0)
46 goto Elong;
47 end -= component->len;
48 memcpy(end, component->data, component->len);
49 *--end = '/';
50 }
51 return end;
52Elong:
53 return ERR_PTR(-ENAMETOOLONG);
54}
55
56/*
57 * return the path component of "<server>:<path>"
58 * nfspath - the "<server>:<path>" string
59 * end - one past the last char that could contain "<server>:"
60 * returns NULL on failure
61 */
62static char *nfs_path_component(const char *nfspath, const char *end)
63{
64 char *p;
65
66 if (*nfspath == '[') {
67 /* parse [] escaped IPv6 addrs */
68 p = strchr(nfspath, ']');
69 if (p != NULL && ++p < end && *p == ':')
70 return p + 1;
71 } else {
72 /* otherwise split on first colon */
73 p = strchr(nfspath, ':');
74 if (p != NULL && p < end)
75 return p + 1;
76 }
77 return NULL;
78}
79
80/*
81 * Determine the mount path as a string
82 */
83static char *nfs4_path(struct dentry *dentry, char *buffer, ssize_t buflen)
84{
85 char *limit;
86 char *path = nfs_path(&limit, dentry, buffer, buflen,
87 NFS_PATH_CANONICAL);
88 if (!IS_ERR(path)) {
89 char *path_component = nfs_path_component(path, limit);
90 if (path_component)
91 return path_component;
92 }
93 return path;
94}
95
96/*
97 * Check that fs_locations::fs_root [RFC3530 6.3] is a prefix for what we
98 * believe to be the server path to this dentry
99 */
100static int nfs4_validate_fspath(struct dentry *dentry,
101 const struct nfs4_fs_locations *locations,
102 char *page, char *page2)
103{
104 const char *path, *fs_path;
105
106 path = nfs4_path(dentry, page, PAGE_SIZE);
107 if (IS_ERR(path))
108 return PTR_ERR(path);
109
110 fs_path = nfs4_pathname_string(&locations->fs_path, page2, PAGE_SIZE);
111 if (IS_ERR(fs_path))
112 return PTR_ERR(fs_path);
113
114 if (strncmp(path, fs_path, strlen(fs_path)) != 0) {
115 dprintk("%s: path %s does not begin with fsroot %s\n",
116 __func__, path, fs_path);
117 return -ENOENT;
118 }
119
120 return 0;
121}
122
123static size_t nfs_parse_server_name(char *string, size_t len,
124 struct sockaddr *sa, size_t salen, struct net *net)
125{
126 ssize_t ret;
127
128 ret = rpc_pton(net, string, len, sa, salen);
129 if (ret == 0) {
130 ret = nfs_dns_resolve_name(net, string, len, sa, salen);
131 if (ret < 0)
132 ret = 0;
133 }
134 return ret;
135}
136
137/**
138 * nfs_find_best_sec - Find a security mechanism supported locally
139 * @server: NFS server struct
140 * @flavors: List of security tuples returned by SECINFO procedure
141 *
142 * Return the pseudoflavor of the first security mechanism in
143 * "flavors" that is locally supported. Return RPC_AUTH_UNIX if
144 * no matching flavor is found in the array. The "flavors" array
145 * is searched in the order returned from the server, per RFC 3530
146 * recommendation.
147 */
148static rpc_authflavor_t nfs_find_best_sec(struct nfs_server *server,
149 struct nfs4_secinfo_flavors *flavors)
150{
151 rpc_authflavor_t pseudoflavor;
152 struct nfs4_secinfo4 *secinfo;
153 unsigned int i;
154
155 for (i = 0; i < flavors->num_flavors; i++) {
156 secinfo = &flavors->flavors[i];
157
158 switch (secinfo->flavor) {
159 case RPC_AUTH_NULL:
160 case RPC_AUTH_UNIX:
161 case RPC_AUTH_GSS:
162 pseudoflavor = rpcauth_get_pseudoflavor(secinfo->flavor,
163 &secinfo->flavor_info);
164 /* make sure pseudoflavor matches sec= mount opt */
165 if (pseudoflavor != RPC_AUTH_MAXFLAVOR &&
166 nfs_auth_info_match(&server->auth_info,
167 pseudoflavor))
168 return pseudoflavor;
169 break;
170 }
171 }
172
173 /* if there were any sec= options then nothing matched */
174 if (server->auth_info.flavor_len > 0)
175 return -EPERM;
176
177 return RPC_AUTH_UNIX;
178}
179
180static rpc_authflavor_t nfs4_negotiate_security(struct inode *inode, struct qstr *name)
181{
182 struct page *page;
183 struct nfs4_secinfo_flavors *flavors;
184 rpc_authflavor_t flavor;
185 int err;
186
187 page = alloc_page(GFP_KERNEL);
188 if (!page)
189 return -ENOMEM;
190 flavors = page_address(page);
191
192 err = nfs4_proc_secinfo(inode, name, flavors);
193 if (err < 0) {
194 flavor = err;
195 goto out;
196 }
197
198 flavor = nfs_find_best_sec(NFS_SERVER(inode), flavors);
199
200out:
201 put_page(page);
202 return flavor;
203}
204
205/*
206 * Please call rpc_shutdown_client() when you are done with this client.
207 */
208struct rpc_clnt *nfs4_create_sec_client(struct rpc_clnt *clnt, struct inode *inode,
209 struct qstr *name)
210{
211 rpc_authflavor_t flavor;
212
213 flavor = nfs4_negotiate_security(inode, name);
214 if ((int)flavor < 0)
215 return ERR_PTR((int)flavor);
216
217 return rpc_clone_client_set_auth(clnt, flavor);
218}
219
220static struct vfsmount *try_location(struct nfs_clone_mount *mountdata,
221 char *page, char *page2,
222 const struct nfs4_fs_location *location)
223{
224 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
225 struct net *net = rpc_net_ns(NFS_SB(mountdata->sb)->client);
226 struct vfsmount *mnt = ERR_PTR(-ENOENT);
227 char *mnt_path;
228 unsigned int maxbuflen;
229 unsigned int s;
230
231 mnt_path = nfs4_pathname_string(&location->rootpath, page2, PAGE_SIZE);
232 if (IS_ERR(mnt_path))
233 return ERR_CAST(mnt_path);
234 mountdata->mnt_path = mnt_path;
235 maxbuflen = mnt_path - 1 - page2;
236
237 mountdata->addr = kmalloc(addr_bufsize, GFP_KERNEL);
238 if (mountdata->addr == NULL)
239 return ERR_PTR(-ENOMEM);
240
241 for (s = 0; s < location->nservers; s++) {
242 const struct nfs4_string *buf = &location->servers[s];
243
244 if (buf->len <= 0 || buf->len >= maxbuflen)
245 continue;
246
247 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len))
248 continue;
249
250 mountdata->addrlen = nfs_parse_server_name(buf->data, buf->len,
251 mountdata->addr, addr_bufsize, net);
252 if (mountdata->addrlen == 0)
253 continue;
254
255 rpc_set_port(mountdata->addr, NFS_PORT);
256
257 memcpy(page2, buf->data, buf->len);
258 page2[buf->len] = '\0';
259 mountdata->hostname = page2;
260
261 snprintf(page, PAGE_SIZE, "%s:%s",
262 mountdata->hostname,
263 mountdata->mnt_path);
264
265 mnt = vfs_kern_mount(&nfs4_referral_fs_type, 0, page, mountdata);
266 if (!IS_ERR(mnt))
267 break;
268 }
269 kfree(mountdata->addr);
270 return mnt;
271}
272
273/**
274 * nfs_follow_referral - set up mountpoint when hitting a referral on moved error
275 * @dentry - parent directory
276 * @locations - array of NFSv4 server location information
277 *
278 */
279static struct vfsmount *nfs_follow_referral(struct dentry *dentry,
280 const struct nfs4_fs_locations *locations)
281{
282 struct vfsmount *mnt = ERR_PTR(-ENOENT);
283 struct nfs_clone_mount mountdata = {
284 .sb = dentry->d_sb,
285 .dentry = dentry,
286 .authflavor = NFS_SB(dentry->d_sb)->client->cl_auth->au_flavor,
287 };
288 char *page = NULL, *page2 = NULL;
289 int loc, error;
290
291 if (locations == NULL || locations->nlocations <= 0)
292 goto out;
293
294 dprintk("%s: referral at %pd2\n", __func__, dentry);
295
296 page = (char *) __get_free_page(GFP_USER);
297 if (!page)
298 goto out;
299
300 page2 = (char *) __get_free_page(GFP_USER);
301 if (!page2)
302 goto out;
303
304 /* Ensure fs path is a prefix of current dentry path */
305 error = nfs4_validate_fspath(dentry, locations, page, page2);
306 if (error < 0) {
307 mnt = ERR_PTR(error);
308 goto out;
309 }
310
311 for (loc = 0; loc < locations->nlocations; loc++) {
312 const struct nfs4_fs_location *location = &locations->locations[loc];
313
314 if (location == NULL || location->nservers <= 0 ||
315 location->rootpath.ncomponents == 0)
316 continue;
317
318 mnt = try_location(&mountdata, page, page2, location);
319 if (!IS_ERR(mnt))
320 break;
321 }
322
323out:
324 free_page((unsigned long) page);
325 free_page((unsigned long) page2);
326 dprintk("%s: done\n", __func__);
327 return mnt;
328}
329
330/*
331 * nfs_do_refmount - handle crossing a referral on server
332 * @dentry - dentry of referral
333 *
334 */
335static struct vfsmount *nfs_do_refmount(struct rpc_clnt *client, struct dentry *dentry)
336{
337 struct vfsmount *mnt = ERR_PTR(-ENOMEM);
338 struct dentry *parent;
339 struct nfs4_fs_locations *fs_locations = NULL;
340 struct page *page;
341 int err;
342
343 /* BUG_ON(IS_ROOT(dentry)); */
344 dprintk("%s: enter\n", __func__);
345
346 page = alloc_page(GFP_KERNEL);
347 if (page == NULL)
348 goto out;
349
350 fs_locations = kmalloc(sizeof(struct nfs4_fs_locations), GFP_KERNEL);
351 if (fs_locations == NULL)
352 goto out_free;
353
354 /* Get locations */
355 mnt = ERR_PTR(-ENOENT);
356
357 parent = dget_parent(dentry);
358 dprintk("%s: getting locations for %pd2\n",
359 __func__, dentry);
360
361 err = nfs4_proc_fs_locations(client, parent->d_inode, &dentry->d_name, fs_locations, page);
362 dput(parent);
363 if (err != 0 ||
364 fs_locations->nlocations <= 0 ||
365 fs_locations->fs_path.ncomponents <= 0)
366 goto out_free;
367
368 mnt = nfs_follow_referral(dentry, fs_locations);
369out_free:
370 __free_page(page);
371 kfree(fs_locations);
372out:
373 dprintk("%s: done\n", __func__);
374 return mnt;
375}
376
377struct vfsmount *nfs4_submount(struct nfs_server *server, struct dentry *dentry,
378 struct nfs_fh *fh, struct nfs_fattr *fattr)
379{
380 rpc_authflavor_t flavor = server->client->cl_auth->au_flavor;
381 struct dentry *parent = dget_parent(dentry);
382 struct inode *dir = parent->d_inode;
383 struct qstr *name = &dentry->d_name;
384 struct rpc_clnt *client;
385 struct vfsmount *mnt;
386
387 /* Look it up again to get its attributes and sec flavor */
388 client = nfs4_proc_lookup_mountpoint(dir, name, fh, fattr);
389 dput(parent);
390 if (IS_ERR(client))
391 return ERR_CAST(client);
392
393 if (fattr->valid & NFS_ATTR_FATTR_V4_REFERRAL) {
394 mnt = nfs_do_refmount(client, dentry);
395 goto out;
396 }
397
398 if (client->cl_auth->au_flavor != flavor)
399 flavor = client->cl_auth->au_flavor;
400 else {
401 rpc_authflavor_t new = nfs4_negotiate_security(dir, name);
402 if ((int)new >= 0)
403 flavor = new;
404 }
405 mnt = nfs_do_submount(dentry, fh, fattr, flavor);
406out:
407 rpc_shutdown_client(client);
408 return mnt;
409}
410
411/*
412 * Try one location from the fs_locations array.
413 *
414 * Returns zero on success, or a negative errno value.
415 */
416static int nfs4_try_replacing_one_location(struct nfs_server *server,
417 char *page, char *page2,
418 const struct nfs4_fs_location *location)
419{
420 const size_t addr_bufsize = sizeof(struct sockaddr_storage);
421 struct net *net = rpc_net_ns(server->client);
422 struct sockaddr *sap;
423 unsigned int s;
424 size_t salen;
425 int error;
426
427 sap = kmalloc(addr_bufsize, GFP_KERNEL);
428 if (sap == NULL)
429 return -ENOMEM;
430
431 error = -ENOENT;
432 for (s = 0; s < location->nservers; s++) {
433 const struct nfs4_string *buf = &location->servers[s];
434 char *hostname;
435
436 if (buf->len <= 0 || buf->len > PAGE_SIZE)
437 continue;
438
439 if (memchr(buf->data, IPV6_SCOPE_DELIMITER, buf->len) != NULL)
440 continue;
441
442 salen = nfs_parse_server_name(buf->data, buf->len,
443 sap, addr_bufsize, net);
444 if (salen == 0)
445 continue;
446 rpc_set_port(sap, NFS_PORT);
447
448 error = -ENOMEM;
449 hostname = kstrndup(buf->data, buf->len, GFP_KERNEL);
450 if (hostname == NULL)
451 break;
452
453 error = nfs4_update_server(server, hostname, sap, salen, net);
454 kfree(hostname);
455 if (error == 0)
456 break;
457 }
458
459 kfree(sap);
460 return error;
461}
462
463/**
464 * nfs4_replace_transport - set up transport to destination server
465 *
466 * @server: export being migrated
467 * @locations: fs_locations array
468 *
469 * Returns zero on success, or a negative errno value.
470 *
471 * The client tries all the entries in the "locations" array, in the
472 * order returned by the server, until one works or the end of the
473 * array is reached.
474 */
475int nfs4_replace_transport(struct nfs_server *server,
476 const struct nfs4_fs_locations *locations)
477{
478 char *page = NULL, *page2 = NULL;
479 int loc, error;
480
481 error = -ENOENT;
482 if (locations == NULL || locations->nlocations <= 0)
483 goto out;
484
485 error = -ENOMEM;
486 page = (char *) __get_free_page(GFP_USER);
487 if (!page)
488 goto out;
489 page2 = (char *) __get_free_page(GFP_USER);
490 if (!page2)
491 goto out;
492
493 for (loc = 0; loc < locations->nlocations; loc++) {
494 const struct nfs4_fs_location *location =
495 &locations->locations[loc];
496
497 if (location == NULL || location->nservers <= 0 ||
498 location->rootpath.ncomponents == 0)
499 continue;
500
501 error = nfs4_try_replacing_one_location(server, page,
502 page2, location);
503 if (error == 0)
504 break;
505 }
506
507out:
508 free_page((unsigned long)page);
509 free_page((unsigned long)page2);
510 return error;
511}