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 * @timeo: deciseconds the mount waits for a response before it retries
140 * @retrans: number of times the mount retries a request
141 *
142 * Uses timeout parameters specified by caller. On successful return, the
143 * auth_flavs list and auth_flav_len will be populated with the list from the
144 * server or a faked-up list if the server didn't provide one.
145 */
nfs_mount(struct nfs_mount_request * info,int timeo,int retrans)146 int nfs_mount(struct nfs_mount_request *info, int timeo, int retrans)
147 {
148 struct rpc_timeout mnt_timeout;
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 .timeout = &mnt_timeout,
164 .servername = info->hostname,
165 .program = &mnt_program,
166 .version = info->version,
167 .authflavor = RPC_AUTH_UNIX,
168 .cred = current_cred(),
169 };
170 struct rpc_clnt *mnt_clnt;
171 int status;
172
173 dprintk("NFS: sending MNT request for %s:%s\n",
174 (info->hostname ? info->hostname : "server"),
175 info->dirpath);
176
177 if (strlen(info->dirpath) > MNTPATHLEN)
178 return -ENAMETOOLONG;
179
180 if (info->noresvport)
181 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
182
183 nfs_init_timeout_values(&mnt_timeout, info->protocol, timeo, retrans);
184 mnt_clnt = rpc_create(&args);
185 if (IS_ERR(mnt_clnt))
186 goto out_clnt_err;
187
188 if (info->version == NFS_MNT3_VERSION)
189 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC3_MNT];
190 else
191 msg.rpc_proc = &mnt_clnt->cl_procinfo[MOUNTPROC_MNT];
192
193 status = rpc_call_sync(mnt_clnt, &msg, RPC_TASK_SOFT|RPC_TASK_TIMEOUT);
194 rpc_shutdown_client(mnt_clnt);
195
196 if (status < 0)
197 goto out_call_err;
198 if (result.errno != 0)
199 goto out_mnt_err;
200
201 dprintk("NFS: MNT request succeeded\n");
202 status = 0;
203
204 /*
205 * If the server didn't provide a flavor list, allow the
206 * client to try any flavor.
207 */
208 if (info->version != NFS_MNT3_VERSION || *info->auth_flav_len == 0) {
209 dprintk("NFS: Faking up auth_flavs list\n");
210 info->auth_flavs[0] = RPC_AUTH_NULL;
211 *info->auth_flav_len = 1;
212 }
213 out:
214 return status;
215
216 out_clnt_err:
217 status = PTR_ERR(mnt_clnt);
218 dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
219 goto out;
220
221 out_call_err:
222 dprintk("NFS: MNT request failed, status=%d\n", status);
223 goto out;
224
225 out_mnt_err:
226 dprintk("NFS: MNT server returned result %d\n", result.errno);
227 status = result.errno;
228 goto out;
229 }
230
231 /**
232 * nfs_umount - Notify a server that we have unmounted this export
233 * @info: pointer to umount request arguments
234 *
235 * MOUNTPROC_UMNT is advisory, so we set a short timeout, and always
236 * use UDP.
237 */
nfs_umount(const struct nfs_mount_request * info)238 void nfs_umount(const struct nfs_mount_request *info)
239 {
240 static const struct rpc_timeout nfs_umnt_timeout = {
241 .to_initval = 1 * HZ,
242 .to_maxval = 3 * HZ,
243 .to_retries = 2,
244 };
245 struct rpc_create_args args = {
246 .net = info->net,
247 .protocol = IPPROTO_UDP,
248 .address = info->sap,
249 .addrsize = info->salen,
250 .timeout = &nfs_umnt_timeout,
251 .servername = info->hostname,
252 .program = &mnt_program,
253 .version = info->version,
254 .authflavor = RPC_AUTH_UNIX,
255 .flags = RPC_CLNT_CREATE_NOPING,
256 .cred = current_cred(),
257 };
258 struct rpc_message msg = {
259 .rpc_argp = info->dirpath,
260 };
261 struct rpc_clnt *clnt;
262 int status;
263
264 if (strlen(info->dirpath) > MNTPATHLEN)
265 return;
266
267 if (info->noresvport)
268 args.flags |= RPC_CLNT_CREATE_NONPRIVPORT;
269
270 clnt = rpc_create(&args);
271 if (IS_ERR(clnt))
272 goto out_clnt_err;
273
274 dprintk("NFS: sending UMNT request for %s:%s\n",
275 (info->hostname ? info->hostname : "server"), info->dirpath);
276
277 if (info->version == NFS_MNT3_VERSION)
278 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC3_UMNT];
279 else
280 msg.rpc_proc = &clnt->cl_procinfo[MOUNTPROC_UMNT];
281
282 status = rpc_call_sync(clnt, &msg, 0);
283 rpc_shutdown_client(clnt);
284
285 if (unlikely(status < 0))
286 goto out_call_err;
287
288 return;
289
290 out_clnt_err:
291 dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
292 PTR_ERR(clnt));
293 return;
294
295 out_call_err:
296 dprintk("NFS: UMNT request failed, status=%d\n", status);
297 }
298
299 /*
300 * XDR encode/decode functions for MOUNT
301 */
302
encode_mntdirpath(struct xdr_stream * xdr,const char * pathname)303 static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
304 {
305 const u32 pathname_len = strlen(pathname);
306 __be32 *p;
307
308 p = xdr_reserve_space(xdr, 4 + pathname_len);
309 xdr_encode_opaque(p, pathname, pathname_len);
310 }
311
mnt_xdr_enc_dirpath(struct rpc_rqst * req,struct xdr_stream * xdr,const void * dirpath)312 static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
313 const void *dirpath)
314 {
315 encode_mntdirpath(xdr, dirpath);
316 }
317
318 /*
319 * RFC 1094: "A non-zero status indicates some sort of error. In this
320 * case, the status is a UNIX error number." This can be problematic
321 * if the server and client use different errno values for the same
322 * error.
323 *
324 * However, the OpenGroup XNFS spec provides a simple mapping that is
325 * independent of local errno values on the server and the client.
326 */
decode_status(struct xdr_stream * xdr,struct mountres * res)327 static int decode_status(struct xdr_stream *xdr, struct mountres *res)
328 {
329 unsigned int i;
330 u32 status;
331 __be32 *p;
332
333 p = xdr_inline_decode(xdr, 4);
334 if (unlikely(p == NULL))
335 return -EIO;
336 status = be32_to_cpup(p);
337
338 for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
339 if (mnt_errtbl[i].status == status) {
340 res->errno = mnt_errtbl[i].errno;
341 return 0;
342 }
343 }
344
345 dprintk("NFS: unrecognized MNT status code: %u\n", status);
346 res->errno = -EACCES;
347 return 0;
348 }
349
decode_fhandle(struct xdr_stream * xdr,struct mountres * res)350 static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
351 {
352 struct nfs_fh *fh = res->fh;
353 __be32 *p;
354
355 p = xdr_inline_decode(xdr, NFS2_FHSIZE);
356 if (unlikely(p == NULL))
357 return -EIO;
358
359 fh->size = NFS2_FHSIZE;
360 memcpy(fh->data, p, NFS2_FHSIZE);
361 return 0;
362 }
363
mnt_xdr_dec_mountres(struct rpc_rqst * req,struct xdr_stream * xdr,void * data)364 static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
365 struct xdr_stream *xdr,
366 void *data)
367 {
368 struct mountres *res = data;
369 int status;
370
371 status = decode_status(xdr, res);
372 if (unlikely(status != 0 || res->errno != 0))
373 return status;
374 return decode_fhandle(xdr, res);
375 }
376
decode_fhs_status(struct xdr_stream * xdr,struct mountres * res)377 static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
378 {
379 unsigned int i;
380 u32 status;
381 __be32 *p;
382
383 p = xdr_inline_decode(xdr, 4);
384 if (unlikely(p == NULL))
385 return -EIO;
386 status = be32_to_cpup(p);
387
388 for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
389 if (mnt3_errtbl[i].status == status) {
390 res->errno = mnt3_errtbl[i].errno;
391 return 0;
392 }
393 }
394
395 dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
396 res->errno = -EACCES;
397 return 0;
398 }
399
decode_fhandle3(struct xdr_stream * xdr,struct mountres * res)400 static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
401 {
402 struct nfs_fh *fh = res->fh;
403 u32 size;
404 __be32 *p;
405
406 p = xdr_inline_decode(xdr, 4);
407 if (unlikely(p == NULL))
408 return -EIO;
409
410 size = be32_to_cpup(p);
411 if (size > NFS3_FHSIZE || size == 0)
412 return -EIO;
413
414 p = xdr_inline_decode(xdr, size);
415 if (unlikely(p == NULL))
416 return -EIO;
417
418 fh->size = size;
419 memcpy(fh->data, p, size);
420 return 0;
421 }
422
decode_auth_flavors(struct xdr_stream * xdr,struct mountres * res)423 static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
424 {
425 rpc_authflavor_t *flavors = res->auth_flavors;
426 unsigned int *count = res->auth_count;
427 u32 entries, i;
428 __be32 *p;
429
430 if (*count == 0)
431 return 0;
432
433 p = xdr_inline_decode(xdr, 4);
434 if (unlikely(p == NULL))
435 return -EIO;
436 entries = be32_to_cpup(p);
437 dprintk("NFS: received %u auth flavors\n", entries);
438 if (entries > NFS_MAX_SECFLAVORS)
439 entries = NFS_MAX_SECFLAVORS;
440
441 p = xdr_inline_decode(xdr, 4 * entries);
442 if (unlikely(p == NULL))
443 return -EIO;
444
445 if (entries > *count)
446 entries = *count;
447
448 for (i = 0; i < entries; i++) {
449 flavors[i] = be32_to_cpup(p++);
450 dprintk("NFS: auth flavor[%u]: %d\n", i, flavors[i]);
451 }
452 *count = i;
453
454 return 0;
455 }
456
mnt_xdr_dec_mountres3(struct rpc_rqst * req,struct xdr_stream * xdr,void * data)457 static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
458 struct xdr_stream *xdr,
459 void *data)
460 {
461 struct mountres *res = data;
462 int status;
463
464 status = decode_fhs_status(xdr, res);
465 if (unlikely(status != 0 || res->errno != 0))
466 return status;
467 status = decode_fhandle3(xdr, res);
468 if (unlikely(status != 0)) {
469 res->errno = -EBADHANDLE;
470 return 0;
471 }
472 return decode_auth_flavors(xdr, res);
473 }
474
475 static const struct rpc_procinfo mnt_procedures[] = {
476 [MOUNTPROC_MNT] = {
477 .p_proc = MOUNTPROC_MNT,
478 .p_encode = mnt_xdr_enc_dirpath,
479 .p_decode = mnt_xdr_dec_mountres,
480 .p_arglen = MNT_enc_dirpath_sz,
481 .p_replen = MNT_dec_mountres_sz,
482 .p_statidx = MOUNTPROC_MNT,
483 .p_name = "MOUNT",
484 },
485 [MOUNTPROC_UMNT] = {
486 .p_proc = MOUNTPROC_UMNT,
487 .p_encode = mnt_xdr_enc_dirpath,
488 .p_arglen = MNT_enc_dirpath_sz,
489 .p_statidx = MOUNTPROC_UMNT,
490 .p_name = "UMOUNT",
491 },
492 };
493
494 static const struct rpc_procinfo mnt3_procedures[] = {
495 [MOUNTPROC3_MNT] = {
496 .p_proc = MOUNTPROC3_MNT,
497 .p_encode = mnt_xdr_enc_dirpath,
498 .p_decode = mnt_xdr_dec_mountres3,
499 .p_arglen = MNT_enc_dirpath_sz,
500 .p_replen = MNT_dec_mountres3_sz,
501 .p_statidx = MOUNTPROC3_MNT,
502 .p_name = "MOUNT",
503 },
504 [MOUNTPROC3_UMNT] = {
505 .p_proc = MOUNTPROC3_UMNT,
506 .p_encode = mnt_xdr_enc_dirpath,
507 .p_arglen = MNT_enc_dirpath_sz,
508 .p_statidx = MOUNTPROC3_UMNT,
509 .p_name = "UMOUNT",
510 },
511 };
512
513 static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
514 static const struct rpc_version mnt_version1 = {
515 .number = 1,
516 .nrprocs = ARRAY_SIZE(mnt_procedures),
517 .procs = mnt_procedures,
518 .counts = mnt_counts,
519 };
520
521 static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
522 static const struct rpc_version mnt_version3 = {
523 .number = 3,
524 .nrprocs = ARRAY_SIZE(mnt3_procedures),
525 .procs = mnt3_procedures,
526 .counts = mnt3_counts,
527 };
528
529 static const struct rpc_version *mnt_version[] = {
530 NULL,
531 &mnt_version1,
532 NULL,
533 &mnt_version3,
534 };
535
536 static struct rpc_stat mnt_stats;
537
538 static const struct rpc_program mnt_program = {
539 .name = "mount",
540 .number = NFS_MNT_PROGRAM,
541 .nrvers = ARRAY_SIZE(mnt_version),
542 .version = mnt_version,
543 .stats = &mnt_stats,
544 };
545