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_fhs_status_sz (1)
33 #define MNT_fhandle_sz XDR_QUADLEN(NFS2_FHSIZE)
34 #define MNT_fhandle3_sz (1 + XDR_QUADLEN(NFS3_FHSIZE))
35 #define MNT_authflav3_sz (1 + NFS_MAX_SECFLAVORS)
36
37 /*
38 * XDR argument and result sizes
39 */
40 #define MNT_enc_dirpath_sz encode_dirpath_sz
41 #define MNT_dec_mountres_sz (MNT_status_sz + MNT_fhandle_sz)
42 #define MNT_dec_mountres3_sz (MNT_status_sz + MNT_fhandle_sz + \
43 MNT_authflav3_sz)
44
45 /*
46 * Defined by RFC 1094, section A.5
47 */
48 enum {
49 MOUNTPROC_NULL = 0,
50 MOUNTPROC_MNT = 1,
51 MOUNTPROC_DUMP = 2,
52 MOUNTPROC_UMNT = 3,
53 MOUNTPROC_UMNTALL = 4,
54 MOUNTPROC_EXPORT = 5,
55 };
56
57 /*
58 * Defined by RFC 1813, section 5.2
59 */
60 enum {
61 MOUNTPROC3_NULL = 0,
62 MOUNTPROC3_MNT = 1,
63 MOUNTPROC3_DUMP = 2,
64 MOUNTPROC3_UMNT = 3,
65 MOUNTPROC3_UMNTALL = 4,
66 MOUNTPROC3_EXPORT = 5,
67 };
68
69 static const struct rpc_program mnt_program;
70
71 /*
72 * Defined by OpenGroup XNFS Version 3W, chapter 8
73 */
74 enum mountstat {
75 MNT_OK = 0,
76 MNT_EPERM = 1,
77 MNT_ENOENT = 2,
78 MNT_EACCES = 13,
79 MNT_EINVAL = 22,
80 };
81
82 static struct {
83 u32 status;
84 int errno;
85 } mnt_errtbl[] = {
86 { .status = MNT_OK, .errno = 0, },
87 { .status = MNT_EPERM, .errno = -EPERM, },
88 { .status = MNT_ENOENT, .errno = -ENOENT, },
89 { .status = MNT_EACCES, .errno = -EACCES, },
90 { .status = MNT_EINVAL, .errno = -EINVAL, },
91 };
92
93 /*
94 * Defined by RFC 1813, section 5.1.5
95 */
96 enum mountstat3 {
97 MNT3_OK = 0, /* no error */
98 MNT3ERR_PERM = 1, /* Not owner */
99 MNT3ERR_NOENT = 2, /* No such file or directory */
100 MNT3ERR_IO = 5, /* I/O error */
101 MNT3ERR_ACCES = 13, /* Permission denied */
102 MNT3ERR_NOTDIR = 20, /* Not a directory */
103 MNT3ERR_INVAL = 22, /* Invalid argument */
104 MNT3ERR_NAMETOOLONG = 63, /* Filename too long */
105 MNT3ERR_NOTSUPP = 10004, /* Operation not supported */
106 MNT3ERR_SERVERFAULT = 10006, /* A failure on the server */
107 };
108
109 static struct {
110 u32 status;
111 int errno;
112 } mnt3_errtbl[] = {
113 { .status = MNT3_OK, .errno = 0, },
114 { .status = MNT3ERR_PERM, .errno = -EPERM, },
115 { .status = MNT3ERR_NOENT, .errno = -ENOENT, },
116 { .status = MNT3ERR_IO, .errno = -EIO, },
117 { .status = MNT3ERR_ACCES, .errno = -EACCES, },
118 { .status = MNT3ERR_NOTDIR, .errno = -ENOTDIR, },
119 { .status = MNT3ERR_INVAL, .errno = -EINVAL, },
120 { .status = MNT3ERR_NAMETOOLONG, .errno = -ENAMETOOLONG, },
121 { .status = MNT3ERR_NOTSUPP, .errno = -ENOTSUPP, },
122 { .status = MNT3ERR_SERVERFAULT, .errno = -EREMOTEIO, },
123 };
124
125 struct mountres {
126 int errno;
127 struct nfs_fh *fh;
128 unsigned int *auth_count;
129 rpc_authflavor_t *auth_flavors;
130 };
131
132 struct mnt_fhstatus {
133 u32 status;
134 struct nfs_fh *fh;
135 };
136
137 /**
138 * nfs_mount - Obtain an NFS file handle for the given host and path
139 * @info: pointer to mount request arguments
140 *
141 * Uses default timeout parameters specified by underlying transport. On
142 * successful return, the auth_flavs list and auth_flav_len will be populated
143 * with the list from the server or a faked-up list if the server didn't
144 * provide one.
145 */
nfs_mount(struct nfs_mount_request * info)146 int nfs_mount(struct nfs_mount_request *info)
147 {
148 struct mountres result = {
149 .fh = info->fh,
150 .auth_count = info->auth_flav_len,
151 .auth_flavors = info->auth_flavs,
152 };
153 struct rpc_message msg = {
154 .rpc_argp = info->dirpath,
155 .rpc_resp = &result,
156 };
157 struct rpc_create_args args = {
158 .net = info->net,
159 .protocol = info->protocol,
160 .address = info->sap,
161 .addrsize = info->salen,
162 .servername = info->hostname,
163 .program = &mnt_program,
164 .version = info->version,
165 .authflavor = RPC_AUTH_UNIX,
166 .cred = current_cred(),
167 };
168 struct rpc_clnt *mnt_clnt;
169 int status;
170
171 dprintk("NFS: sending MNT request for %s:%s\n",
172 (info->hostname ? info->hostname : "server"),
173 info->dirpath);
174
175 if (strlen(info->dirpath) > MNTPATHLEN)
176 return -ENAMETOOLONG;
177
178 if (info->noresvport)
179 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
180
181 mnt_clnt = rpc_create(&args);
182 if (IS_ERR(mnt_clnt))
183 goto out_clnt_err;
184
185 if (info->version == NFS_MNT3_VERSION)
186 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
187 else
188 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
189
190 status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
191 rpc_shutdown_client(mnt_clnt);
192
193 if (status < 0)
194 goto out_call_err;
195 if (result.errno != 0)
196 goto out_mnt_err;
197
198 dprintk("NFS: MNT request succeeded\n");
199 status = 0;
200
201 /*
202 * If the server didn't provide a flavor list, allow the
203 * client to try any flavor.
204 */
205 if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
206 dprintk("NFS: Faking up auth_flavs list\n");
207 info->auth_flavs[0] = RPC_AUTH_NULL;
208 *info->auth_flav_len = 1;
209 }
210 out:
211 return status;
212
213 out_clnt_err:
214 status = PTR_ERR(mnt_clnt);
215 dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
216 goto out;
217
218 out_call_err:
219 dprintk("NFS: MNT request failed, status=%d\n", status);
220 goto out;
221
222 out_mnt_err:
223 dprintk("NFS: MNT server returned result %d\n", result.errno);
224 status = result.errno;
225 goto out;
226 }
227
228 /**
229 * nfs_umount - Notify a server that we have unmounted this export
230 * @info: pointer to umount request arguments
231 *
232 * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
233 * use UDP.
234 */
nfs_umount(const struct nfs_mount_request * info)235 void nfs_umount(const struct nfs_mount_request *info)
236 {
237 static const struct rpc_timeout nfs_umnt_timeout = {
238 .to_initval = 1 * HZ,
239 .to_maxval = 3 * HZ,
240 .to_retries = 2,
241 };
242 struct rpc_create_args args = {
243 .net = info->net,
244 .protocol = IPPROTO_UDP,
245 .address = info->sap,
246 .addrsize = info->salen,
247 .timeout = &nfs_umnt_timeout,
248 .servername = info->hostname,
249 .program = &mnt_program,
250 .version = info->version,
251 .authflavor = RPC_AUTH_UNIX,
252 .flags = RPC_CLNT_CREATE_NOPING,
253 .cred = current_cred(),
254 };
255 struct rpc_message msg = {
256 .rpc_argp = info->dirpath,
257 };
258 struct rpc_clnt *clnt;
259 int status;
260
261 if (strlen(info->dirpath) > MNTPATHLEN)
262 return;
263
264 if (info->noresvport)
265 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
266
267 clnt = rpc_create(&args);
268 if (IS_ERR(clnt))
269 goto out_clnt_err;
270
271 dprintk("NFS: sending UMNT request for %s:%s\n",
272 (info->hostname ? info->hostname : "server"), info->dirpath);
273
274 if (info->version == NFS_MNT3_VERSION)
275 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
276 else
277 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
278
279 status = rpc_call_sync(clnt, &msg, 0);
280 rpc_shutdown_client(clnt);
281
282 if (unlikely(status < 0))
283 goto out_call_err;
284
285 return;
286
287 out_clnt_err:
288 dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
289 PTR_ERR(clnt));
290 return;
291
292 out_call_err:
293 dprintk("NFS: UMNT request failed, status=%d\n", status);
294 }
295
296 /*
297 * XDR encode/decode functions for MOUNT
298 */
299
encode_mntdirpath(struct xdr_stream * xdr,const char * pathname)300 static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
301 {
302 const u32 pathname_len = strlen(pathname);
303 __be32 *p;
304
305 p = xdr_reserve_space(xdr, 4 + pathname_len);
306 xdr_encode_opaque(p, pathname, pathname_len);
307 }
308
mnt_xdr_enc_dirpath(struct rpc_rqst * req,struct xdr_stream * xdr,const void * dirpath)309 static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
310 const void *dirpath)
311 {
312 encode_mntdirpath(xdr, dirpath);
313 }
314
315 /*
316 * RFC 1094: "A non-zero status indicates some sort of error. In this
317 * case, the status is a UNIX error number." This can be problematic
318 * if the server and client use different errno values for the same
319 * error.
320 *
321 * However, the OpenGroup XNFS spec provides a simple mapping that is
322 * independent of local errno values on the server and the client.
323 */
decode_status(struct xdr_stream * xdr,struct mountres * res)324 static int decode_status(struct xdr_stream *xdr, struct mountres *res)
325 {
326 unsigned int i;
327 u32 status;
328 __be32 *p;
329
330 p = xdr_inline_decode(xdr, 4);
331 if (unlikely(p == NULL))
332 return -EIO;
333 status = be32_to_cpup(p);
334
335 for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
336 if (mnt_errtbl[i].status == status) {
337 res->errno = mnt_errtbl[i].errno;
338 return 0;
339 }
340 }
341
342 dprintk("NFS: unrecognized MNT status code: %u\n", status);
343 res->errno = -EACCES;
344 return 0;
345 }
346
decode_fhandle(struct xdr_stream * xdr,struct mountres * res)347 static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
348 {
349 struct nfs_fh *fh = res->fh;
350 __be32 *p;
351
352 p = xdr_inline_decode(xdr, NFS2_FHSIZE);
353 if (unlikely(p == NULL))
354 return -EIO;
355
356 fh->size = NFS2_FHSIZE;
357 memcpy(fh->data, p, NFS2_FHSIZE);
358 return 0;
359 }
360
mnt_xdr_dec_mountres(struct rpc_rqst * req,struct xdr_stream * xdr,void * data)361 static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
362 struct xdr_stream *xdr,
363 void *data)
364 {
365 struct mountres *res = data;
366 int status;
367
368 status = decode_status(xdr, res);
369 if (unlikely(status != 0 || res->errno != 0))
370 return status;
371 return decode_fhandle(xdr, res);
372 }
373
decode_fhs_status(struct xdr_stream * xdr,struct mountres * res)374 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
375 {
376 unsigned int i;
377 u32 status;
378 __be32 *p;
379
380 p = xdr_inline_decode(xdr, 4);
381 if (unlikely(p == NULL))
382 return -EIO;
383 status = be32_to_cpup(p);
384
385 for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
386 if (mnt3_errtbl[i].status == status) {
387 res->errno = mnt3_errtbl[i].errno;
388 return 0;
389 }
390 }
391
392 dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
393 res->errno = -EACCES;
394 return 0;
395 }
396
decode_fhandle3(struct xdr_stream * xdr,struct mountres * res)397 static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
398 {
399 struct nfs_fh *fh = res->fh;
400 u32 size;
401 __be32 *p;
402
403 p = xdr_inline_decode(xdr, 4);
404 if (unlikely(p == NULL))
405 return -EIO;
406
407 size = be32_to_cpup(p);
408 if (size > NFS3_FHSIZE || size == 0)
409 return -EIO;
410
411 p = xdr_inline_decode(xdr, size);
412 if (unlikely(p == NULL))
413 return -EIO;
414
415 fh->size = size;
416 memcpy(fh->data, p, size);
417 return 0;
418 }
419
decode_auth_flavors(struct xdr_stream * xdr,struct mountres * res)420 static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
421 {
422 rpc_authflavor_t *flavors = res->auth_flavors;
423 unsigned int *count = res->auth_count;
424 u32 entries, i;
425 __be32 *p;
426
427 if (*count == 0)
428 return 0;
429
430 p = xdr_inline_decode(xdr, 4);
431 if (unlikely(p == NULL))
432 return -EIO;
433 entries = be32_to_cpup(p);
434 dprintk("NFS: received %u auth flavors\n", entries);
435 if (entries > NFS_MAX_SECFLAVORS)
436 entries = NFS_MAX_SECFLAVORS;
437
438 p = xdr_inline_decode(xdr, 4 * entries);
439 if (unlikely(p == NULL))
440 return -EIO;
441
442 if (entries > *count)
443 entries = *count;
444
445 for (i = 0; i < entries; i++) {
446 flavors[i] = be32_to_cpup(p++);
447 dprintk("NFS: auth flavor[%u]: %d\n", i, flavors[i]);
448 }
449 *count = i;
450
451 return 0;
452 }
453
mnt_xdr_dec_mountres3(struct rpc_rqst * req,struct xdr_stream * xdr,void * data)454 static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
455 struct xdr_stream *xdr,
456 void *data)
457 {
458 struct mountres *res = data;
459 int status;
460
461 status = decode_fhs_status(xdr, res);
462 if (unlikely(status != 0 || res->errno != 0))
463 return status;
464 status = decode_fhandle3(xdr, res);
465 if (unlikely(status != 0)) {
466 res->errno = -EBADHANDLE;
467 return 0;
468 }
469 return decode_auth_flavors(xdr, res);
470 }
471
472 static const struct rpc_procinfo mnt_procedures[] = {
473 [MOUNTPROC_MNT] = {
474 .p_proc = MOUNTPROC_MNT,
475 .p_encode = mnt_xdr_enc_dirpath,
476 .p_decode = mnt_xdr_dec_mountres,
477 .p_arglen = MNT_enc_dirpath_sz,
478 .p_replen = MNT_dec_mountres_sz,
479 .p_statidx = MOUNTPROC_MNT,
480 .p_name = "MOUNT",
481 },
482 [MOUNTPROC_UMNT] = {
483 .p_proc = MOUNTPROC_UMNT,
484 .p_encode = mnt_xdr_enc_dirpath,
485 .p_arglen = MNT_enc_dirpath_sz,
486 .p_statidx = MOUNTPROC_UMNT,
487 .p_name = "UMOUNT",
488 },
489 };
490
491 static const struct rpc_procinfo mnt3_procedures[] = {
492 [MOUNTPROC3_MNT] = {
493 .p_proc = MOUNTPROC3_MNT,
494 .p_encode = mnt_xdr_enc_dirpath,
495 .p_decode = mnt_xdr_dec_mountres3,
496 .p_arglen = MNT_enc_dirpath_sz,
497 .p_replen = MNT_dec_mountres3_sz,
498 .p_statidx = MOUNTPROC3_MNT,
499 .p_name = "MOUNT",
500 },
501 [MOUNTPROC3_UMNT] = {
502 .p_proc = MOUNTPROC3_UMNT,
503 .p_encode = mnt_xdr_enc_dirpath,
504 .p_arglen = MNT_enc_dirpath_sz,
505 .p_statidx = MOUNTPROC3_UMNT,
506 .p_name = "UMOUNT",
507 },
508 };
509
510 static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
511 static const struct rpc_version mnt_version1 = {
512 .number = 1,
513 .nrprocs = ARRAY_SIZE(mnt_procedures),
514 .procs = mnt_procedures,
515 .counts = mnt_counts,
516 };
517
518 static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
519 static const struct rpc_version mnt_version3 = {
520 .number = 3,
521 .nrprocs = ARRAY_SIZE(mnt3_procedures),
522 .procs = mnt3_procedures,
523 .counts = mnt3_counts,
524 };
525
526 static const struct rpc_version *mnt_version[] = {
527 NULL,
528 &mnt_version1,
529 NULL,
530 &mnt_version3,
531 };
532
533 static struct rpc_stat mnt_stats;
534
535 static const struct rpc_program mnt_program = {
536 .name = "mount",
537 .number = NFS_MNT_PROGRAM,
538 .nrvers = ARRAY_SIZE(mnt_version),
539 .version = mnt_version,
540 .stats = &mnt_stats,
541 };
542
