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 struct mnt_fhstatus {
132 u32 status;
133 struct nfs_fh *fh;
134 };
135
136 /**
137 * nfs_mount - Obtain an NFS file handle for the given host and path
138 * @info: pointer to mount request arguments
139 *
140 * Uses default timeout parameters specified by underlying transport. On
141 * successful return, the auth_flavs list and auth_flav_len will be populated
142 * with the list from the server or a faked-up list if the server didn't
143 * provide one.
144 */
nfs_mount(struct nfs_mount_request * info)145 int nfs_mount(struct nfs_mount_request *info)
146 {
147 struct mountres result = {
148 .fh = info->fh,
149 .auth_count = info->auth_flav_len,
150 .auth_flavors = info->auth_flavs,
151 };
152 struct rpc_message msg = {
153 .rpc_argp = info->dirpath,
154 .rpc_resp = &result,
155 };
156 struct rpc_create_args args = {
157 .net = info->net,
158 .protocol = info->protocol,
159 .address = info->sap,
160 .addrsize = info->salen,
161 .servername = info->hostname,
162 .program = &mnt_program,
163 .version = info->version,
164 .authflavor = RPC_AUTH_UNIX,
165 .cred = current_cred(),
166 };
167 struct rpc_clnt *mnt_clnt;
168 int status;
169
170 dprintk("NFS: sending MNT request for %s:%s\n",
171 (info->hostname ? info->hostname : "server"),
172 info->dirpath);
173
174 if (strlen(info->dirpath) > MNTPATHLEN)
175 return -ENAMETOOLONG;
176
177 if (info->noresvport)
178 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
179
180 mnt_clnt = rpc_create(&args);
181 if (IS_ERR(mnt_clnt))
182 goto out_clnt_err;
183
184 if (info->version == NFS_MNT3_VERSION)
185 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
186 else
187 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
188
189 status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
190 rpc_shutdown_client(mnt_clnt);
191
192 if (status < 0)
193 goto out_call_err;
194 if (result.errno != 0)
195 goto out_mnt_err;
196
197 dprintk("NFS: MNT request succeeded\n");
198 status = 0;
199
200 /*
201 * If the server didn't provide a flavor list, allow the
202 * client to try any flavor.
203 */
204 if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
205 dprintk("NFS: Faking up auth_flavs list\n");
206 info->auth_flavs[0] = RPC_AUTH_NULL;
207 *info->auth_flav_len = 1;
208 }
209 out:
210 return status;
211
212 out_clnt_err:
213 status = PTR_ERR(mnt_clnt);
214 dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
215 goto out;
216
217 out_call_err:
218 dprintk("NFS: MNT request failed, status=%d\n", status);
219 goto out;
220
221 out_mnt_err:
222 dprintk("NFS: MNT server returned result %d\n", result.errno);
223 status = result.errno;
224 goto out;
225 }
226
227 /**
228 * nfs_umount - Notify a server that we have unmounted this export
229 * @info: pointer to umount request arguments
230 *
231 * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
232 * use UDP.
233 */
nfs_umount(const struct nfs_mount_request * info)234 void nfs_umount(const struct nfs_mount_request *info)
235 {
236 static const struct rpc_timeout nfs_umnt_timeout = {
237 .to_initval = 1 * HZ,
238 .to_maxval = 3 * HZ,
239 .to_retries = 2,
240 };
241 struct rpc_create_args args = {
242 .net = info->net,
243 .protocol = IPPROTO_UDP,
244 .address = info->sap,
245 .addrsize = info->salen,
246 .timeout = &nfs_umnt_timeout,
247 .servername = info->hostname,
248 .program = &mnt_program,
249 .version = info->version,
250 .authflavor = RPC_AUTH_UNIX,
251 .flags = RPC_CLNT_CREATE_NOPING,
252 .cred = current_cred(),
253 };
254 struct rpc_message msg = {
255 .rpc_argp = info->dirpath,
256 };
257 struct rpc_clnt *clnt;
258 int status;
259
260 if (strlen(info->dirpath) > MNTPATHLEN)
261 return;
262
263 if (info->noresvport)
264 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
265
266 clnt = rpc_create(&args);
267 if (IS_ERR(clnt))
268 goto out_clnt_err;
269
270 dprintk("NFS: sending UMNT request for %s:%s\n",
271 (info->hostname ? info->hostname : "server"), info->dirpath);
272
273 if (info->version == NFS_MNT3_VERSION)
274 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
275 else
276 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
277
278 status = rpc_call_sync(clnt, &msg, 0);
279 rpc_shutdown_client(clnt);
280
281 if (unlikely(status < 0))
282 goto out_call_err;
283
284 return;
285
286 out_clnt_err:
287 dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
288 PTR_ERR(clnt));
289 return;
290
291 out_call_err:
292 dprintk("NFS: UMNT request failed, status=%d\n", status);
293 }
294
295 /*
296 * XDR encode/decode functions for MOUNT
297 */
298
encode_mntdirpath(struct xdr_stream * xdr,const char * pathname)299 static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
300 {
301 const u32 pathname_len = strlen(pathname);
302 __be32 *p;
303
304 p = xdr_reserve_space(xdr, 4 + pathname_len);
305 xdr_encode_opaque(p, pathname, pathname_len);
306 }
307
mnt_xdr_enc_dirpath(struct rpc_rqst * req,struct xdr_stream * xdr,const void * dirpath)308 static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
309 const void *dirpath)
310 {
311 encode_mntdirpath(xdr, dirpath);
312 }
313
314 /*
315 * RFC 1094: "A non-zero status indicates some sort of error. In this
316 * case, the status is a UNIX error number." This can be problematic
317 * if the server and client use different errno values for the same
318 * error.
319 *
320 * However, the OpenGroup XNFS spec provides a simple mapping that is
321 * independent of local errno values on the server and the client.
322 */
decode_status(struct xdr_stream * xdr,struct mountres * res)323 static int decode_status(struct xdr_stream *xdr, struct mountres *res)
324 {
325 unsigned int i;
326 u32 status;
327 __be32 *p;
328
329 p = xdr_inline_decode(xdr, 4);
330 if (unlikely(p == NULL))
331 return -EIO;
332 status = be32_to_cpup(p);
333
334 for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
335 if (mnt_errtbl[i].status == status) {
336 res->errno = mnt_errtbl[i].errno;
337 return 0;
338 }
339 }
340
341 dprintk("NFS: unrecognized MNT status code: %u\n", status);
342 res->errno = -EACCES;
343 return 0;
344 }
345
decode_fhandle(struct xdr_stream * xdr,struct mountres * res)346 static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
347 {
348 struct nfs_fh *fh = res->fh;
349 __be32 *p;
350
351 p = xdr_inline_decode(xdr, NFS2_FHSIZE);
352 if (unlikely(p == NULL))
353 return -EIO;
354
355 fh->size = NFS2_FHSIZE;
356 memcpy(fh->data, p, NFS2_FHSIZE);
357 return 0;
358 }
359
mnt_xdr_dec_mountres(struct rpc_rqst * req,struct xdr_stream * xdr,void * data)360 static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
361 struct xdr_stream *xdr,
362 void *data)
363 {
364 struct mountres *res = data;
365 int status;
366
367 status = decode_status(xdr, res);
368 if (unlikely(status != 0 || res->errno != 0))
369 return status;
370 return decode_fhandle(xdr, res);
371 }
372
decode_fhs_status(struct xdr_stream * xdr,struct mountres * res)373 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
374 {
375 unsigned int i;
376 u32 status;
377 __be32 *p;
378
379 p = xdr_inline_decode(xdr, 4);
380 if (unlikely(p == NULL))
381 return -EIO;
382 status = be32_to_cpup(p);
383
384 for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
385 if (mnt3_errtbl[i].status == status) {
386 res->errno = mnt3_errtbl[i].errno;
387 return 0;
388 }
389 }
390
391 dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
392 res->errno = -EACCES;
393 return 0;
394 }
395
decode_fhandle3(struct xdr_stream * xdr,struct mountres * res)396 static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
397 {
398 struct nfs_fh *fh = res->fh;
399 u32 size;
400 __be32 *p;
401
402 p = xdr_inline_decode(xdr, 4);
403 if (unlikely(p == NULL))
404 return -EIO;
405
406 size = be32_to_cpup(p);
407 if (size > NFS3_FHSIZE || size == 0)
408 return -EIO;
409
410 p = xdr_inline_decode(xdr, size);
411 if (unlikely(p == NULL))
412 return -EIO;
413
414 fh->size = size;
415 memcpy(fh->data, p, size);
416 return 0;
417 }
418
decode_auth_flavors(struct xdr_stream * xdr,struct mountres * res)419 static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
420 {
421 rpc_authflavor_t *flavors = res->auth_flavors;
422 unsigned int *count = res->auth_count;
423 u32 entries, i;
424 __be32 *p;
425
426 if (*count == 0)
427 return 0;
428
429 p = xdr_inline_decode(xdr, 4);
430 if (unlikely(p == NULL))
431 return -EIO;
432 entries = be32_to_cpup(p);
433 dprintk("NFS: received %u auth flavors\n", entries);
434 if (entries > NFS_MAX_SECFLAVORS)
435 entries = NFS_MAX_SECFLAVORS;
436
437 p = xdr_inline_decode(xdr, 4 * entries);
438 if (unlikely(p == NULL))
439 return -EIO;
440
441 if (entries > *count)
442 entries = *count;
443
444 for (i = 0; i < entries; i++) {
445 flavors[i] = be32_to_cpup(p++);
446 dprintk("NFS: auth flavor[%u]: %d\n", i, flavors[i]);
447 }
448 *count = i;
449
450 return 0;
451 }
452
mnt_xdr_dec_mountres3(struct rpc_rqst * req,struct xdr_stream * xdr,void * data)453 static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
454 struct xdr_stream *xdr,
455 void *data)
456 {
457 struct mountres *res = data;
458 int status;
459
460 status = decode_fhs_status(xdr, res);
461 if (unlikely(status != 0 || res->errno != 0))
462 return status;
463 status = decode_fhandle3(xdr, res);
464 if (unlikely(status != 0)) {
465 res->errno = -EBADHANDLE;
466 return 0;
467 }
468 return decode_auth_flavors(xdr, res);
469 }
470
471 static const struct rpc_procinfo mnt_procedures[] = {
472 [MOUNTPROC_MNT] = {
473 .p_proc = MOUNTPROC_MNT,
474 .p_encode = mnt_xdr_enc_dirpath,
475 .p_decode = mnt_xdr_dec_mountres,
476 .p_arglen = MNT_enc_dirpath_sz,
477 .p_replen = MNT_dec_mountres_sz,
478 .p_statidx = MOUNTPROC_MNT,
479 .p_name = "MOUNT",
480 },
481 [MOUNTPROC_UMNT] = {
482 .p_proc = MOUNTPROC_UMNT,
483 .p_encode = mnt_xdr_enc_dirpath,
484 .p_arglen = MNT_enc_dirpath_sz,
485 .p_statidx = MOUNTPROC_UMNT,
486 .p_name = "UMOUNT",
487 },
488 };
489
490 static const struct rpc_procinfo mnt3_procedures[] = {
491 [MOUNTPROC3_MNT] = {
492 .p_proc = MOUNTPROC3_MNT,
493 .p_encode = mnt_xdr_enc_dirpath,
494 .p_decode = mnt_xdr_dec_mountres3,
495 .p_arglen = MNT_enc_dirpath_sz,
496 .p_replen = MNT_dec_mountres3_sz,
497 .p_statidx = MOUNTPROC3_MNT,
498 .p_name = "MOUNT",
499 },
500 [MOUNTPROC3_UMNT] = {
501 .p_proc = MOUNTPROC3_UMNT,
502 .p_encode = mnt_xdr_enc_dirpath,
503 .p_arglen = MNT_enc_dirpath_sz,
504 .p_statidx = MOUNTPROC3_UMNT,
505 .p_name = "UMOUNT",
506 },
507 };
508
509 static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
510 static const struct rpc_version mnt_version1 = {
511 .number = 1,
512 .nrprocs = ARRAY_SIZE(mnt_procedures),
513 .procs = mnt_procedures,
514 .counts = mnt_counts,
515 };
516
517 static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
518 static const struct rpc_version mnt_version3 = {
519 .number = 3,
520 .nrprocs = ARRAY_SIZE(mnt3_procedures),
521 .procs = mnt3_procedures,
522 .counts = mnt3_counts,
523 };
524
525 static const struct rpc_version *mnt_version[] = {
526 NULL,
527 &mnt_version1,
528 NULL,
529 &mnt_version3,
530 };
531
532 static struct rpc_stat mnt_stats;
533
534 static const struct rpc_program mnt_program = {
535 .name = "mount",
536 .number = NFS_MNT_PROGRAM,
537 .nrvers = ARRAY_SIZE(mnt_version),
538 .version = mnt_version,
539 .stats = &mnt_stats,
540 };
541