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_fhandlev3_sz XDR_QUADLEN(NFS3_FHSIZE)
36 #define MNT_authflav3_sz (1 + NFS_MAX_SECFLAVORS)
37
38 /*
39 * XDR argument and result sizes
40 */
41 #define MNT_enc_dirpath_sz encode_dirpath_sz
42 #define MNT_dec_mountres_sz (MNT_status_sz + MNT_fhandle_sz)
43 #define MNT_dec_mountres3_sz (MNT_status_sz + MNT_fhandlev3_sz + \
44 MNT_authflav3_sz)
45
46 /*
47 * Defined by RFC 1094, section A.5
48 */
49 enum {
50 MOUNTPROC_NULL = 0,
51 MOUNTPROC_MNT = 1,
52 MOUNTPROC_DUMP = 2,
53 MOUNTPROC_UMNT = 3,
54 MOUNTPROC_UMNTALL = 4,
55 MOUNTPROC_EXPORT = 5,
56 };
57
58 /*
59 * Defined by RFC 1813, section 5.2
60 */
61 enum {
62 MOUNTPROC3_NULL = 0,
63 MOUNTPROC3_MNT = 1,
64 MOUNTPROC3_DUMP = 2,
65 MOUNTPROC3_UMNT = 3,
66 MOUNTPROC3_UMNTALL = 4,
67 MOUNTPROC3_EXPORT = 5,
68 };
69
70 static const struct rpc_program mnt_program;
71
72 /*
73 * Defined by OpenGroup XNFS Version 3W, chapter 8
74 */
75 enum mountstat {
76 MNT_OK = 0,
77 MNT_EPERM = 1,
78 MNT_ENOENT = 2,
79 MNT_EACCES = 13,
80 MNT_EINVAL = 22,
81 };
82
83 static struct {
84 u32 status;
85 int errno;
86 } mnt_errtbl[] = {
87 { .status = MNT_OK, .errno = 0, },
88 { .status = MNT_EPERM, .errno = -EPERM, },
89 { .status = MNT_ENOENT, .errno = -ENOENT, },
90 { .status = MNT_EACCES, .errno = -EACCES, },
91 { .status = MNT_EINVAL, .errno = -EINVAL, },
92 };
93
94 /*
95 * Defined by RFC 1813, section 5.1.5
96 */
97 enum mountstat3 {
98 MNT3_OK = 0, /* no error */
99 MNT3ERR_PERM = 1, /* Not owner */
100 MNT3ERR_NOENT = 2, /* No such file or directory */
101 MNT3ERR_IO = 5, /* I/O error */
102 MNT3ERR_ACCES = 13, /* Permission denied */
103 MNT3ERR_NOTDIR = 20, /* Not a directory */
104 MNT3ERR_INVAL = 22, /* Invalid argument */
105 MNT3ERR_NAMETOOLONG = 63, /* Filename too long */
106 MNT3ERR_NOTSUPP = 10004, /* Operation not supported */
107 MNT3ERR_SERVERFAULT = 10006, /* A failure on the server */
108 };
109
110 static struct {
111 u32 status;
112 int errno;
113 } mnt3_errtbl[] = {
114 { .status = MNT3_OK, .errno = 0, },
115 { .status = MNT3ERR_PERM, .errno = -EPERM, },
116 { .status = MNT3ERR_NOENT, .errno = -ENOENT, },
117 { .status = MNT3ERR_IO, .errno = -EIO, },
118 { .status = MNT3ERR_ACCES, .errno = -EACCES, },
119 { .status = MNT3ERR_NOTDIR, .errno = -ENOTDIR, },
120 { .status = MNT3ERR_INVAL, .errno = -EINVAL, },
121 { .status = MNT3ERR_NAMETOOLONG, .errno = -ENAMETOOLONG, },
122 { .status = MNT3ERR_NOTSUPP, .errno = -ENOTSUPP, },
123 { .status = MNT3ERR_SERVERFAULT, .errno = -EREMOTEIO, },
124 };
125
126 struct mountres {
127 int errno;
128 struct nfs_fh *fh;
129 unsigned int *auth_count;
130 rpc_authflavor_t *auth_flavors;
131 };
132
133 struct mnt_fhstatus {
134 u32 status;
135 struct nfs_fh *fh;
136 };
137
138 /**
139 * nfs_mount - Obtain an NFS file handle for the given host and path
140 * @info: pointer to mount request arguments
141 *
142 * Uses default timeout parameters specified by underlying transport. On
143 * successful return, the auth_flavs list and auth_flav_len will be populated
144 * with the list from the server or a faked-up list if the server didn't
145 * provide one.
146 */
nfs_mount(struct nfs_mount_request * info)147 int nfs_mount(struct nfs_mount_request *info)
148 {
149 struct mountres result = {
150 .fh = info->fh,
151 .auth_count = info->auth_flav_len,
152 .auth_flavors = info->auth_flavs,
153 };
154 struct rpc_message msg = {
155 .rpc_argp = info->dirpath,
156 .rpc_resp = &result,
157 };
158 struct rpc_create_args args = {
159 .net = info->net,
160 .protocol = info->protocol,
161 .address = info->sap,
162 .addrsize = info->salen,
163 .servername = info->hostname,
164 .program = &mnt_program,
165 .version = info->version,
166 .authflavor = RPC_AUTH_UNIX,
167 .cred = current_cred(),
168 };
169 struct rpc_clnt *mnt_clnt;
170 int status;
171
172 dprintk("NFS: sending MNT request for %s:%s\n",
173 (info->hostname ? info->hostname : "server"),
174 info->dirpath);
175
176 if (strlen(info->dirpath) > MNTPATHLEN)
177 return -ENAMETOOLONG;
178
179 if (info->noresvport)
180 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
181
182 mnt_clnt = rpc_create(&args);
183 if (IS_ERR(mnt_clnt))
184 goto out_clnt_err;
185
186 if (info->version == NFS_MNT3_VERSION)
187 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
188 else
189 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
190
191 status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
192 rpc_shutdown_client(mnt_clnt);
193
194 if (status < 0)
195 goto out_call_err;
196 if (result.errno != 0)
197 goto out_mnt_err;
198
199 dprintk("NFS: MNT request succeeded\n");
200 status = 0;
201
202 /*
203 * If the server didn't provide a flavor list, allow the
204 * client to try any flavor.
205 */
206 if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
207 dprintk("NFS: Faking up auth_flavs list\n");
208 info->auth_flavs[0] = RPC_AUTH_NULL;
209 *info->auth_flav_len = 1;
210 }
211 out:
212 return status;
213
214 out_clnt_err:
215 status = PTR_ERR(mnt_clnt);
216 dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
217 goto out;
218
219 out_call_err:
220 dprintk("NFS: MNT request failed, status=%d\n", status);
221 goto out;
222
223 out_mnt_err:
224 dprintk("NFS: MNT server returned result %d\n", result.errno);
225 status = result.errno;
226 goto out;
227 }
228
229 /**
230 * nfs_umount - Notify a server that we have unmounted this export
231 * @info: pointer to umount request arguments
232 *
233 * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
234 * use UDP.
235 */
nfs_umount(const struct nfs_mount_request * info)236 void nfs_umount(const struct nfs_mount_request *info)
237 {
238 static const struct rpc_timeout nfs_umnt_timeout = {
239 .to_initval = 1 * HZ,
240 .to_maxval = 3 * HZ,
241 .to_retries = 2,
242 };
243 struct rpc_create_args args = {
244 .net = info->net,
245 .protocol = IPPROTO_UDP,
246 .address = info->sap,
247 .addrsize = info->salen,
248 .timeout = &nfs_umnt_timeout,
249 .servername = info->hostname,
250 .program = &mnt_program,
251 .version = info->version,
252 .authflavor = RPC_AUTH_UNIX,
253 .flags = RPC_CLNT_CREATE_NOPING,
254 .cred = current_cred(),
255 };
256 struct rpc_message msg = {
257 .rpc_argp = info->dirpath,
258 };
259 struct rpc_clnt *clnt;
260 int status;
261
262 if (strlen(info->dirpath) > MNTPATHLEN)
263 return;
264
265 if (info->noresvport)
266 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
267
268 clnt = rpc_create(&args);
269 if (IS_ERR(clnt))
270 goto out_clnt_err;
271
272 dprintk("NFS: sending UMNT request for %s:%s\n",
273 (info->hostname ? info->hostname : "server"), info->dirpath);
274
275 if (info->version == NFS_MNT3_VERSION)
276 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
277 else
278 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
279
280 status = rpc_call_sync(clnt, &msg, 0);
281 rpc_shutdown_client(clnt);
282
283 if (unlikely(status < 0))
284 goto out_call_err;
285
286 return;
287
288 out_clnt_err:
289 dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
290 PTR_ERR(clnt));
291 return;
292
293 out_call_err:
294 dprintk("NFS: UMNT request failed, status=%d\n", status);
295 }
296
297 /*
298 * XDR encode/decode functions for MOUNT
299 */
300
encode_mntdirpath(struct xdr_stream * xdr,const char * pathname)301 static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
302 {
303 const u32 pathname_len = strlen(pathname);
304 __be32 *p;
305
306 p = xdr_reserve_space(xdr, 4 + pathname_len);
307 xdr_encode_opaque(p, pathname, pathname_len);
308 }
309
mnt_xdr_enc_dirpath(struct rpc_rqst * req,struct xdr_stream * xdr,const void * dirpath)310 static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
311 const void *dirpath)
312 {
313 encode_mntdirpath(xdr, dirpath);
314 }
315
316 /*
317 * RFC 1094: "A non-zero status indicates some sort of error. In this
318 * case, the status is a UNIX error number." This can be problematic
319 * if the server and client use different errno values for the same
320 * error.
321 *
322 * However, the OpenGroup XNFS spec provides a simple mapping that is
323 * independent of local errno values on the server and the client.
324 */
decode_status(struct xdr_stream * xdr,struct mountres * res)325 static int decode_status(struct xdr_stream *xdr, struct mountres *res)
326 {
327 unsigned int i;
328 u32 status;
329 __be32 *p;
330
331 p = xdr_inline_decode(xdr, 4);
332 if (unlikely(p == NULL))
333 return -EIO;
334 status = be32_to_cpup(p);
335
336 for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
337 if (mnt_errtbl[i].status == status) {
338 res->errno = mnt_errtbl[i].errno;
339 return 0;
340 }
341 }
342
343 dprintk("NFS: unrecognized MNT status code: %u\n", status);
344 res->errno = -EACCES;
345 return 0;
346 }
347
decode_fhandle(struct xdr_stream * xdr,struct mountres * res)348 static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
349 {
350 struct nfs_fh *fh = res->fh;
351 __be32 *p;
352
353 p = xdr_inline_decode(xdr, NFS2_FHSIZE);
354 if (unlikely(p == NULL))
355 return -EIO;
356
357 fh->size = NFS2_FHSIZE;
358 memcpy(fh->data, p, NFS2_FHSIZE);
359 return 0;
360 }
361
mnt_xdr_dec_mountres(struct rpc_rqst * req,struct xdr_stream * xdr,void * data)362 static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
363 struct xdr_stream *xdr,
364 void *data)
365 {
366 struct mountres *res = data;
367 int status;
368
369 status = decode_status(xdr, res);
370 if (unlikely(status != 0 || res->errno != 0))
371 return status;
372 return decode_fhandle(xdr, res);
373 }
374
decode_fhs_status(struct xdr_stream * xdr,struct mountres * res)375 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
376 {
377 unsigned int i;
378 u32 status;
379 __be32 *p;
380
381 p = xdr_inline_decode(xdr, 4);
382 if (unlikely(p == NULL))
383 return -EIO;
384 status = be32_to_cpup(p);
385
386 for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
387 if (mnt3_errtbl[i].status == status) {
388 res->errno = mnt3_errtbl[i].errno;
389 return 0;
390 }
391 }
392
393 dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
394 res->errno = -EACCES;
395 return 0;
396 }
397
decode_fhandle3(struct xdr_stream * xdr,struct mountres * res)398 static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
399 {
400 struct nfs_fh *fh = res->fh;
401 u32 size;
402 __be32 *p;
403
404 p = xdr_inline_decode(xdr, 4);
405 if (unlikely(p == NULL))
406 return -EIO;
407
408 size = be32_to_cpup(p);
409 if (size > NFS3_FHSIZE || size == 0)
410 return -EIO;
411
412 p = xdr_inline_decode(xdr, size);
413 if (unlikely(p == NULL))
414 return -EIO;
415
416 fh->size = size;
417 memcpy(fh->data, p, size);
418 return 0;
419 }
420
decode_auth_flavors(struct xdr_stream * xdr,struct mountres * res)421 static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
422 {
423 rpc_authflavor_t *flavors = res->auth_flavors;
424 unsigned int *count = res->auth_count;
425 u32 entries, i;
426 __be32 *p;
427
428 if (*count == 0)
429 return 0;
430
431 p = xdr_inline_decode(xdr, 4);
432 if (unlikely(p == NULL))
433 return -EIO;
434 entries = be32_to_cpup(p);
435 dprintk("NFS: received %u auth flavors\n", entries);
436 if (entries > NFS_MAX_SECFLAVORS)
437 entries = NFS_MAX_SECFLAVORS;
438
439 p = xdr_inline_decode(xdr, 4 * entries);
440 if (unlikely(p == NULL))
441 return -EIO;
442
443 if (entries > *count)
444 entries = *count;
445
446 for (i = 0; i < entries; i++) {
447 flavors[i] = be32_to_cpup(p++);
448 dprintk("NFS: auth flavor[%u]: %d\n", i, flavors[i]);
449 }
450 *count = i;
451
452 return 0;
453 }
454
mnt_xdr_dec_mountres3(struct rpc_rqst * req,struct xdr_stream * xdr,void * data)455 static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
456 struct xdr_stream *xdr,
457 void *data)
458 {
459 struct mountres *res = data;
460 int status;
461
462 status = decode_fhs_status(xdr, res);
463 if (unlikely(status != 0 || res->errno != 0))
464 return status;
465 status = decode_fhandle3(xdr, res);
466 if (unlikely(status != 0)) {
467 res->errno = -EBADHANDLE;
468 return 0;
469 }
470 return decode_auth_flavors(xdr, res);
471 }
472
473 static const struct rpc_procinfo mnt_procedures[] = {
474 [MOUNTPROC_MNT] = {
475 .p_proc = MOUNTPROC_MNT,
476 .p_encode = mnt_xdr_enc_dirpath,
477 .p_decode = mnt_xdr_dec_mountres,
478 .p_arglen = MNT_enc_dirpath_sz,
479 .p_replen = MNT_dec_mountres_sz,
480 .p_statidx = MOUNTPROC_MNT,
481 .p_name = "MOUNT",
482 },
483 [MOUNTPROC_UMNT] = {
484 .p_proc = MOUNTPROC_UMNT,
485 .p_encode = mnt_xdr_enc_dirpath,
486 .p_arglen = MNT_enc_dirpath_sz,
487 .p_statidx = MOUNTPROC_UMNT,
488 .p_name = "UMOUNT",
489 },
490 };
491
492 static const struct rpc_procinfo mnt3_procedures[] = {
493 [MOUNTPROC3_MNT] = {
494 .p_proc = MOUNTPROC3_MNT,
495 .p_encode = mnt_xdr_enc_dirpath,
496 .p_decode = mnt_xdr_dec_mountres3,
497 .p_arglen = MNT_enc_dirpath_sz,
498 .p_replen = MNT_dec_mountres3_sz,
499 .p_statidx = MOUNTPROC3_MNT,
500 .p_name = "MOUNT",
501 },
502 [MOUNTPROC3_UMNT] = {
503 .p_proc = MOUNTPROC3_UMNT,
504 .p_encode = mnt_xdr_enc_dirpath,
505 .p_arglen = MNT_enc_dirpath_sz,
506 .p_statidx = MOUNTPROC3_UMNT,
507 .p_name = "UMOUNT",
508 },
509 };
510
511 static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
512 static const struct rpc_version mnt_version1 = {
513 .number = 1,
514 .nrprocs = ARRAY_SIZE(mnt_procedures),
515 .procs = mnt_procedures,
516 .counts = mnt_counts,
517 };
518
519 static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
520 static const struct rpc_version mnt_version3 = {
521 .number = 3,
522 .nrprocs = ARRAY_SIZE(mnt3_procedures),
523 .procs = mnt3_procedures,
524 .counts = mnt3_counts,
525 };
526
527 static const struct rpc_version *mnt_version[] = {
528 NULL,
529 &mnt_version1,
530 NULL,
531 &mnt_version3,
532 };
533
534 static struct rpc_stat mnt_stats;
535
536 static const struct rpc_program mnt_program = {
537 .name = "mount",
538 .number = NFS_MNT_PROGRAM,
539 .nrvers = ARRAY_SIZE(mnt_version),
540 .version = mnt_version,
541 .stats = &mnt_stats,
542 };
543