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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 | */ | |
32 | static 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; | |
52 | Elong: | |
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 | */ | |
62 | static 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 | */ | |
83 | static 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 | */ | |
100 | static 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 | ||
123 | static 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 | */ | |
148 | static 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 | ||
180 | static 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 | ||
200 | out: | |
201 | put_page(page); | |
202 | return flavor; | |
203 | } | |
204 | ||
205 | /* | |
206 | * Please call rpc_shutdown_client() when you are done with this client. | |
207 | */ | |
208 | struct 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 | ||
220 | static 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 | */ | |
279 | static 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 | ||
323 | out: | |
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 | */ | |
335 | static 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); | |
369 | out_free: | |
370 | __free_page(page); | |
371 | kfree(fs_locations); | |
372 | out: | |
373 | dprintk("%s: done\n", __func__); | |
374 | return mnt; | |
375 | } | |
376 | ||
377 | struct 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); | |
406 | out: | |
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 | */ | |
416 | static 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 | */ | |
475 | int 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 | ||
507 | out: | |
508 | free_page((unsigned long)page); | |
509 | free_page((unsigned long)page2); | |
510 | return error; | |
511 | } |