1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * In-kernel MOUNT protocol client
4 *
5 * Copyright (C) 1997, Olaf Kirch <okir@monad.swb.de>
6 */
7
8 #include <linux/types.h>
9 #include <linux/socket.h>
10 #include <linux/kernel.h>
11 #include <linux/errno.h>
12 #include <linux/uio.h>
13 #include <linux/net.h>
14 #include <linux/in.h>
15 #include <linux/sunrpc/clnt.h>
16 #include <linux/sunrpc/sched.h>
17 #include <linux/nfs_fs.h>
18 #include "internal.h"
19
20 #define NFSDBG_FACILITY NFSDBG_MOUNT
21
22 /*
23 * Defined by RFC 1094, section A.3; and RFC 1813, section 5.1.4
24 */
25 #define MNTPATHLEN (1024)
26
27 /*
28 * XDR data type sizes
29 */
30 #define encode_dirpath_sz (1 + XDR_QUADLEN(MNTPATHLEN))
31 #define MNT_status_sz (1)
32 #define MNT_fhandle_sz XDR_QUADLEN(NFS2_FHSIZE)
33 #define MNT_fhandlev3_sz XDR_QUADLEN(NFS3_FHSIZE)
34 #define MNT_authflav3_sz (1 + NFS_MAX_SECFLAVORS)
35
36 /*
37 * XDR argument and result sizes
38 */
39 #define MNT_enc_dirpath_sz encode_dirpath_sz
40 #define MNT_dec_mountres_sz (MNT_status_sz + MNT_fhandle_sz)
41 #define MNT_dec_mountres3_sz (MNT_status_sz + MNT_fhandlev3_sz + \
42 MNT_authflav3_sz)
43
44 /*
45 * Defined by RFC 1094, section A.5
46 */
47 enum {
48 MOUNTPROC_NULL = 0,
49 MOUNTPROC_MNT = 1,
50 MOUNTPROC_DUMP = 2,
51 MOUNTPROC_UMNT = 3,
52 MOUNTPROC_UMNTALL = 4,
53 MOUNTPROC_EXPORT = 5,
54 };
55
56 /*
57 * Defined by RFC 1813, section 5.2
58 */
59 enum {
60 MOUNTPROC3_NULL = 0,
61 MOUNTPROC3_MNT = 1,
62 MOUNTPROC3_DUMP = 2,
63 MOUNTPROC3_UMNT = 3,
64 MOUNTPROC3_UMNTALL = 4,
65 MOUNTPROC3_EXPORT = 5,
66 };
67
68 static const struct rpc_program mnt_program;
69
70 /*
71 * Defined by OpenGroup XNFS Version 3W, chapter 8
72 */
73 enum mountstat {
74 MNT_OK = 0,
75 MNT_EPERM = 1,
76 MNT_ENOENT = 2,
77 MNT_EACCES = 13,
78 MNT_EINVAL = 22,
79 };
80
81 static struct {
82 u32 status;
83 int errno;
84 } mnt_errtbl[] = {
85 { .status = MNT_OK, .errno = 0, },
86 { .status = MNT_EPERM, .errno = -EPERM, },
87 { .status = MNT_ENOENT, .errno = -ENOENT, },
88 { .status = MNT_EACCES, .errno = -EACCES, },
89 { .status = MNT_EINVAL, .errno = -EINVAL, },
90 };
91
92 /*
93 * Defined by RFC 1813, section 5.1.5
94 */
95 enum mountstat3 {
96 MNT3_OK = 0, /* no error */
97 MNT3ERR_PERM = 1, /* Not owner */
98 MNT3ERR_NOENT = 2, /* No such file or directory */
99 MNT3ERR_IO = 5, /* I/O error */
100 MNT3ERR_ACCES = 13, /* Permission denied */
101 MNT3ERR_NOTDIR = 20, /* Not a directory */
102 MNT3ERR_INVAL = 22, /* Invalid argument */
103 MNT3ERR_NAMETOOLONG = 63, /* Filename too long */
104 MNT3ERR_NOTSUPP = 10004, /* Operation not supported */
105 MNT3ERR_SERVERFAULT = 10006, /* A failure on the server */
106 };
107
108 static struct {
109 u32 status;
110 int errno;
111 } mnt3_errtbl[] = {
112 { .status = MNT3_OK, .errno = 0, },
113 { .status = MNT3ERR_PERM, .errno = -EPERM, },
114 { .status = MNT3ERR_NOENT, .errno = -ENOENT, },
115 { .status = MNT3ERR_IO, .errno = -EIO, },
116 { .status = MNT3ERR_ACCES, .errno = -EACCES, },
117 { .status = MNT3ERR_NOTDIR, .errno = -ENOTDIR, },
118 { .status = MNT3ERR_INVAL, .errno = -EINVAL, },
119 { .status = MNT3ERR_NAMETOOLONG, .errno = -ENAMETOOLONG, },
120 { .status = MNT3ERR_NOTSUPP, .errno = -ENOTSUPP, },
121 { .status = MNT3ERR_SERVERFAULT, .errno = -EREMOTEIO, },
122 };
123
124 struct mountres {
125 int errno;
126 struct nfs_fh *fh;
127 unsigned int *auth_count;
128 rpc_authflavor_t *auth_flavors;
129 };
130
131 /**
132 * nfs_mount - Obtain an NFS file handle for the given host and path
133 * @info: pointer to mount request arguments
134 * @timeo: deciseconds the mount waits for a response before it retries
135 * @retrans: number of times the mount retries a request
136 *
137 * Uses timeout parameters specified by caller. On successful return, the
138 * auth_flavs list and auth_flav_len will be populated with the list from the
139 * server or a faked-up list if the server didn't provide one.
140 */
141 int nfs_mount(struct nfs_mount_request *info, int timeo, int retrans)
142 {
143 struct rpc_timeout mnt_timeout;
144 struct mountres result = {
145 .fh = info->fh,
146 .auth_count = info->auth_flav_len,
147 .auth_flavors = info->auth_flavs,
148 };
149 struct rpc_message msg = {
150 .rpc_argp = info->dirpath,
151 .rpc_resp = &result,
152 };
153 struct rpc_create_args args = {
154 .net = info->net,
155 .protocol = info->protocol,
156 .address = (struct sockaddr *)info->sap,
157 .addrsize = info->salen,
158 .timeout = &mnt_timeout,
159 .servername = info->hostname,
160 .program = &mnt_program,
161 .version = info->version,
162 .authflavor = RPC_AUTH_UNIX,
163 .cred = current_cred(),
164 };
165 struct rpc_clnt *mnt_clnt;
166 int status;
167
168 dprintk("NFS: sending MNT request for %s:%s\n",
169 (info->hostname ? info->hostname : "server"),
170 info->dirpath);
171
172 if (strlen(info->dirpath) > MNTPATHLEN)
173 return -ENAMETOOLONG;
174
175 if (info->noresvport)
176 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
177
178 nfs_init_timeout_values(&mnt_timeout, info->protocol, timeo, retrans);
179 mnt_clnt = rpc_create(&args);
180 if (IS_ERR(mnt_clnt))
181 goto out_clnt_err;
182
183 if (info->version == NFS_MNT3_VERSION)
184 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
185 else
186 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
187
188 status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
189 rpc_shutdown_client(mnt_clnt);
190
191 if (status < 0)
192 goto out_call_err;
193 if (result.errno != 0)
194 goto out_mnt_err;
195
196 dprintk("NFS: MNT request succeeded\n");
197 status = 0;
198
199 /*
200 * If the server didn't provide a flavor list, allow the
201 * client to try any flavor.
202 */
203 if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
204 dprintk("NFS: Faking up auth_flavs list\n");
205 info->auth_flavs[0] = RPC_AUTH_NULL;
206 *info->auth_flav_len = 1;
207 }
208 out:
209 return status;
210
211 out_clnt_err:
212 status = PTR_ERR(mnt_clnt);
213 dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
214 goto out;
215
216 out_call_err:
217 dprintk("NFS: MNT request failed, status=%d\n", status);
218 goto out;
219
220 out_mnt_err:
221 dprintk("NFS: MNT server returned result %d\n", result.errno);
222 status = result.errno;
223 goto out;
224 }
225
226 /**
227 * nfs_umount - Notify a server that we have unmounted this export
228 * @info: pointer to umount request arguments
229 *
230 * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
231 * use UDP.
232 */
233 void nfs_umount(const struct nfs_mount_request *info)
234 {
235 static const struct rpc_timeout nfs_umnt_timeout = {
236 .to_initval = 1 * HZ,
237 .to_maxval = 3 * HZ,
238 .to_retries = 2,
239 };
240 struct rpc_create_args args = {
241 .net = info->net,
242 .protocol = IPPROTO_UDP,
243 .address = (struct sockaddr *)info->sap,
244 .addrsize = info->salen,
245 .timeout = &nfs_umnt_timeout,
246 .servername = info->hostname,
247 .program = &mnt_program,
248 .version = info->version,
249 .authflavor = RPC_AUTH_UNIX,
250 .flags = RPC_CLNT_CREATE_NOPING,
251 .cred = current_cred(),
252 };
253 struct rpc_message msg = {
254 .rpc_argp = info->dirpath,
255 };
256 struct rpc_clnt *clnt;
257 int status;
258
259 if (strlen(info->dirpath) > MNTPATHLEN)
260 return;
261
262 if (info->noresvport)
263 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
264
265 clnt = rpc_create(&args);
266 if (IS_ERR(clnt))
267 goto out_clnt_err;
268
269 dprintk("NFS: sending UMNT request for %s:%s\n",
270 (info->hostname ? info->hostname : "server"), info->dirpath);
271
272 if (info->version == NFS_MNT3_VERSION)
273 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
274 else
275 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
276
277 status = rpc_call_sync(clnt, &msg, 0);
278 rpc_shutdown_client(clnt);
279
280 if (unlikely(status < 0))
281 goto out_call_err;
282
283 return;
284
285 out_clnt_err:
286 dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
287 PTR_ERR(clnt));
288 return;
289
290 out_call_err:
291 dprintk("NFS: UMNT request failed, status=%d\n", status);
292 }
293
294 /*
295 * XDR encode/decode functions for MOUNT
296 */
297
298 static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
299 {
300 const u32 pathname_len = strlen(pathname);
301 __be32 *p;
302
303 p = xdr_reserve_space(xdr, 4 + pathname_len);
304 xdr_encode_opaque(p, pathname, pathname_len);
305 }
306
307 static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
308 const void *dirpath)
309 {
310 encode_mntdirpath(xdr, dirpath);
311 }
312
313 /*
314 * RFC 1094: "A non-zero status indicates some sort of error. In this
315 * case, the status is a UNIX error number." This can be problematic
316 * if the server and client use different errno values for the same
317 * error.
318 *
319 * However, the OpenGroup XNFS spec provides a simple mapping that is
320 * independent of local errno values on the server and the client.
321 */
322 static int decode_status(struct xdr_stream *xdr, struct mountres *res)
323 {
324 unsigned int i;
325 u32 status;
326 __be32 *p;
327
328 p = xdr_inline_decode(xdr, 4);
329 if (unlikely(p == NULL))
330 return -EIO;
331 status = be32_to_cpup(p);
332
333 for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
334 if (mnt_errtbl[i].status == status) {
335 res->errno = mnt_errtbl[i].errno;
336 return 0;
337 }
338 }
339
340 dprintk("NFS: unrecognized MNT status code: %u\n", status);
341 res->errno = -EACCES;
342 return 0;
343 }
344
345 static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
346 {
347 struct nfs_fh *fh = res->fh;
348 __be32 *p;
349
350 p = xdr_inline_decode(xdr, NFS2_FHSIZE);
351 if (unlikely(p == NULL))
352 return -EIO;
353
354 fh->size = NFS2_FHSIZE;
355 memcpy(fh->data, p, NFS2_FHSIZE);
356 return 0;
357 }
358
359 static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
360 struct xdr_stream *xdr,
361 void *data)
362 {
363 struct mountres *res = data;
364 int status;
365
366 status = decode_status(xdr, res);
367 if (unlikely(status != 0 || res->errno != 0))
368 return status;
369 return decode_fhandle(xdr, res);
370 }
371
372 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
373 {
374 unsigned int i;
375 u32 status;
376 __be32 *p;
377
378 p = xdr_inline_decode(xdr, 4);
379 if (unlikely(p == NULL))
380 return -EIO;
381 status = be32_to_cpup(p);
382
383 for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
384 if (mnt3_errtbl[i].status == status) {
385 res->errno = mnt3_errtbl[i].errno;
386 return 0;
387 }
388 }
389
390 dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
391 res->errno = -EACCES;
392 return 0;
393 }
394
395 static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
396 {
397 struct nfs_fh *fh = res->fh;
398 u32 size;
399 __be32 *p;
400
401 p = xdr_inline_decode(xdr, 4);
402 if (unlikely(p == NULL))
403 return -EIO;
404
405 size = be32_to_cpup(p);
406 if (size > NFS3_FHSIZE || size == 0)
407 return -EIO;
408
409 p = xdr_inline_decode(xdr, size);
410 if (unlikely(p == NULL))
411 return -EIO;
412
413 fh->size = size;
414 memcpy(fh->data, p, size);
415 return 0;
416 }
417
418 static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
419 {
420 rpc_authflavor_t *flavors = res->auth_flavors;
421 unsigned int *count = res->auth_count;
422 u32 entries, i;
423 __be32 *p;
424
425 if (*count == 0)
426 return 0;
427
428 p = xdr_inline_decode(xdr, 4);
429 if (unlikely(p == NULL))
430 return -EIO;
431 entries = be32_to_cpup(p);
432 dprintk("NFS: received %u auth flavors\n", entries);
433 if (entries > NFS_MAX_SECFLAVORS)
434 entries = NFS_MAX_SECFLAVORS;
435
436 p = xdr_inline_decode(xdr, 4 * entries);
437 if (unlikely(p == NULL))
438 return -EIO;
439
440 if (entries > *count)
441 entries = *count;
442
443 for (i = 0; i < entries; i++) {
444 flavors[i] = be32_to_cpup(p++);
445 dprintk("NFS: auth flavor[%u]: %d\n", i, flavors[i]);
446 }
447 *count = i;
448
449 return 0;
450 }
451
452 static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
453 struct xdr_stream *xdr,
454 void *data)
455 {
456 struct mountres *res = data;
457 int status;
458
459 status = decode_fhs_status(xdr, res);
460 if (unlikely(status != 0 || res->errno != 0))
461 return status;
462 status = decode_fhandle3(xdr, res);
463 if (unlikely(status != 0)) {
464 res->errno = -EBADHANDLE;
465 return 0;
466 }
467 return decode_auth_flavors(xdr, res);
468 }
469
470 static const struct rpc_procinfo mnt_procedures[] = {
471 [MOUNTPROC_MNT] = {
472 .p_proc = MOUNTPROC_MNT,
473 .p_encode = mnt_xdr_enc_dirpath,
474 .p_decode = mnt_xdr_dec_mountres,
475 .p_arglen = MNT_enc_dirpath_sz,
476 .p_replen = MNT_dec_mountres_sz,
477 .p_statidx = MOUNTPROC_MNT,
478 .p_name = "MOUNT",
479 },
480 [MOUNTPROC_UMNT] = {
481 .p_proc = MOUNTPROC_UMNT,
482 .p_encode = mnt_xdr_enc_dirpath,
483 .p_arglen = MNT_enc_dirpath_sz,
484 .p_statidx = MOUNTPROC_UMNT,
485 .p_name = "UMOUNT",
486 },
487 };
488
489 static const struct rpc_procinfo mnt3_procedures[] = {
490 [MOUNTPROC3_MNT] = {
491 .p_proc = MOUNTPROC3_MNT,
492 .p_encode = mnt_xdr_enc_dirpath,
493 .p_decode = mnt_xdr_dec_mountres3,
494 .p_arglen = MNT_enc_dirpath_sz,
495 .p_replen = MNT_dec_mountres3_sz,
496 .p_statidx = MOUNTPROC3_MNT,
497 .p_name = "MOUNT",
498 },
499 [MOUNTPROC3_UMNT] = {
500 .p_proc = MOUNTPROC3_UMNT,
501 .p_encode = mnt_xdr_enc_dirpath,
502 .p_arglen = MNT_enc_dirpath_sz,
503 .p_statidx = MOUNTPROC3_UMNT,
504 .p_name = "UMOUNT",
505 },
506 };
507
508 static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
509 static const struct rpc_version mnt_version1 = {
510 .number = 1,
511 .nrprocs = ARRAY_SIZE(mnt_procedures),
512 .procs = mnt_procedures,
513 .counts = mnt_counts,
514 };
515
516 static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
517 static const struct rpc_version mnt_version3 = {
518 .number = 3,
519 .nrprocs = ARRAY_SIZE(mnt3_procedures),
520 .procs = mnt3_procedures,
521 .counts = mnt3_counts,
522 };
523
524 static const struct rpc_version *mnt_version[] = {
525 NULL,
526 &mnt_version1,
527 NULL,
528 &mnt_version3,
529 };
530
531 static struct rpc_stat mnt_stats;
532
533 static const struct rpc_program mnt_program = {
534 .name = "mount",
535 .number = NFS_MNT_PROGRAM,
536 .nrvers = ARRAY_SIZE(mnt_version),
537 .version = mnt_version,
538 .stats = &mnt_stats,
539 };
540
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