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 */
47enum {
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 */
59enum {
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
68static const struct rpc_program mnt_program;
69
70/*
71 * Defined by OpenGroup XNFS Version 3W, chapter 8
72 */
73enum mountstat {
74 MNT_OK = 0,
75 MNT_EPERM = 1,
76 MNT_ENOENT = 2,
77 MNT_EACCES = 13,
78 MNT_EINVAL = 22,
79};
80
81static 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 */
95enum 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
108static 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
124struct 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 */
141int 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(to: &mnt_timeout, proto: info->protocol, timeo, retrans);
179 mnt_clnt = rpc_create(args: &args);
180 if (IS_ERR(ptr: 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(clnt: mnt_clnt, msg: &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 }
208out:
209 return status;
210
211out_clnt_err:
212 status = PTR_ERR(ptr: mnt_clnt);
213 dprintk("NFS: failed to create MNT RPC client, status=%d\n", status);
214 goto out;
215
216out_call_err:
217 dprintk("NFS: MNT request failed, status=%d\n", status);
218 goto out;
219
220out_mnt_err:
221 dprintk("NFS: MNT server returned result %d\n", result.errno);
222 status = result.errno;
223 goto out;
224}
225
226/*
227 * XDR encode/decode functions for MOUNT
228 */
229
230static void encode_mntdirpath(struct xdr_stream *xdr, const char *pathname)
231{
232 const u32 pathname_len = strlen(pathname);
233 __be32 *p;
234
235 p = xdr_reserve_space(xdr, nbytes: 4 + pathname_len);
236 xdr_encode_opaque(p, ptr: pathname, len: pathname_len);
237}
238
239static void mnt_xdr_enc_dirpath(struct rpc_rqst *req, struct xdr_stream *xdr,
240 const void *dirpath)
241{
242 encode_mntdirpath(xdr, pathname: dirpath);
243}
244
245/*
246 * RFC 1094: "A non-zero status indicates some sort of error. In this
247 * case, the status is a UNIX error number." This can be problematic
248 * if the server and client use different errno values for the same
249 * error.
250 *
251 * However, the OpenGroup XNFS spec provides a simple mapping that is
252 * independent of local errno values on the server and the client.
253 */
254static int decode_status(struct xdr_stream *xdr, struct mountres *res)
255{
256 unsigned int i;
257 u32 status;
258 __be32 *p;
259
260 p = xdr_inline_decode(xdr, nbytes: 4);
261 if (unlikely(p == NULL))
262 return -EIO;
263 status = be32_to_cpup(p);
264
265 for (i = 0; i < ARRAY_SIZE(mnt_errtbl); i++) {
266 if (mnt_errtbl[i].status == status) {
267 res->errno = mnt_errtbl[i].errno;
268 return 0;
269 }
270 }
271
272 dprintk("NFS: unrecognized MNT status code: %u\n", status);
273 res->errno = -EACCES;
274 return 0;
275}
276
277static int decode_fhandle(struct xdr_stream *xdr, struct mountres *res)
278{
279 struct nfs_fh *fh = res->fh;
280 __be32 *p;
281
282 p = xdr_inline_decode(xdr, NFS2_FHSIZE);
283 if (unlikely(p == NULL))
284 return -EIO;
285
286 fh->size = NFS2_FHSIZE;
287 memcpy(fh->data, p, NFS2_FHSIZE);
288 return 0;
289}
290
291static int mnt_xdr_dec_mountres(struct rpc_rqst *req,
292 struct xdr_stream *xdr,
293 void *data)
294{
295 struct mountres *res = data;
296 int status;
297
298 status = decode_status(xdr, res);
299 if (unlikely(status != 0 || res->errno != 0))
300 return status;
301 return decode_fhandle(xdr, res);
302}
303
304static int decode_fhs_status(struct xdr_stream *xdr, struct mountres *res)
305{
306 unsigned int i;
307 u32 status;
308 __be32 *p;
309
310 p = xdr_inline_decode(xdr, nbytes: 4);
311 if (unlikely(p == NULL))
312 return -EIO;
313 status = be32_to_cpup(p);
314
315 for (i = 0; i < ARRAY_SIZE(mnt3_errtbl); i++) {
316 if (mnt3_errtbl[i].status == status) {
317 res->errno = mnt3_errtbl[i].errno;
318 return 0;
319 }
320 }
321
322 dprintk("NFS: unrecognized MNT3 status code: %u\n", status);
323 res->errno = -EACCES;
324 return 0;
325}
326
327static int decode_fhandle3(struct xdr_stream *xdr, struct mountres *res)
328{
329 struct nfs_fh *fh = res->fh;
330 u32 size;
331 __be32 *p;
332
333 p = xdr_inline_decode(xdr, nbytes: 4);
334 if (unlikely(p == NULL))
335 return -EIO;
336
337 size = be32_to_cpup(p);
338 if (size > NFS3_FHSIZE || size == 0)
339 return -EIO;
340
341 p = xdr_inline_decode(xdr, nbytes: size);
342 if (unlikely(p == NULL))
343 return -EIO;
344
345 fh->size = size;
346 memcpy(fh->data, p, size);
347 return 0;
348}
349
350static int decode_auth_flavors(struct xdr_stream *xdr, struct mountres *res)
351{
352 rpc_authflavor_t *flavors = res->auth_flavors;
353 unsigned int *count = res->auth_count;
354 u32 entries, i;
355 __be32 *p;
356
357 if (*count == 0)
358 return 0;
359
360 p = xdr_inline_decode(xdr, nbytes: 4);
361 if (unlikely(p == NULL))
362 return -EIO;
363 entries = be32_to_cpup(p);
364 dprintk("NFS: received %u auth flavors\n", entries);
365 if (entries > NFS_MAX_SECFLAVORS)
366 entries = NFS_MAX_SECFLAVORS;
367
368 p = xdr_inline_decode(xdr, nbytes: 4 * entries);
369 if (unlikely(p == NULL))
370 return -EIO;
371
372 if (entries > *count)
373 entries = *count;
374
375 for (i = 0; i < entries; i++) {
376 flavors[i] = be32_to_cpup(p: p++);
377 dprintk("NFS: auth flavor[%u]: %d\n", i, flavors[i]);
378 }
379 *count = i;
380
381 return 0;
382}
383
384static int mnt_xdr_dec_mountres3(struct rpc_rqst *req,
385 struct xdr_stream *xdr,
386 void *data)
387{
388 struct mountres *res = data;
389 int status;
390
391 status = decode_fhs_status(xdr, res);
392 if (unlikely(status != 0 || res->errno != 0))
393 return status;
394 status = decode_fhandle3(xdr, res);
395 if (unlikely(status != 0)) {
396 res->errno = -EBADHANDLE;
397 return 0;
398 }
399 return decode_auth_flavors(xdr, res);
400}
401
402static const struct rpc_procinfo mnt_procedures[] = {
403 [MOUNTPROC_MNT] = {
404 .p_proc = MOUNTPROC_MNT,
405 .p_encode = mnt_xdr_enc_dirpath,
406 .p_decode = mnt_xdr_dec_mountres,
407 .p_arglen = MNT_enc_dirpath_sz,
408 .p_replen = MNT_dec_mountres_sz,
409 .p_statidx = MOUNTPROC_MNT,
410 .p_name = "MOUNT",
411 },
412 [MOUNTPROC_UMNT] = {
413 .p_proc = MOUNTPROC_UMNT,
414 .p_encode = mnt_xdr_enc_dirpath,
415 .p_arglen = MNT_enc_dirpath_sz,
416 .p_statidx = MOUNTPROC_UMNT,
417 .p_name = "UMOUNT",
418 },
419};
420
421static const struct rpc_procinfo mnt3_procedures[] = {
422 [MOUNTPROC3_MNT] = {
423 .p_proc = MOUNTPROC3_MNT,
424 .p_encode = mnt_xdr_enc_dirpath,
425 .p_decode = mnt_xdr_dec_mountres3,
426 .p_arglen = MNT_enc_dirpath_sz,
427 .p_replen = MNT_dec_mountres3_sz,
428 .p_statidx = MOUNTPROC3_MNT,
429 .p_name = "MOUNT",
430 },
431 [MOUNTPROC3_UMNT] = {
432 .p_proc = MOUNTPROC3_UMNT,
433 .p_encode = mnt_xdr_enc_dirpath,
434 .p_arglen = MNT_enc_dirpath_sz,
435 .p_statidx = MOUNTPROC3_UMNT,
436 .p_name = "UMOUNT",
437 },
438};
439
440static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
441static const struct rpc_version mnt_version1 = {
442 .number = 1,
443 .nrprocs = ARRAY_SIZE(mnt_procedures),
444 .procs = mnt_procedures,
445 .counts = mnt_counts,
446};
447
448static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
449static const struct rpc_version mnt_version3 = {
450 .number = 3,
451 .nrprocs = ARRAY_SIZE(mnt3_procedures),
452 .procs = mnt3_procedures,
453 .counts = mnt3_counts,
454};
455
456static const struct rpc_version *mnt_version[] = {
457 NULL,
458 &mnt_version1,
459 NULL,
460 &mnt_version3,
461};
462
463static struct rpc_stat mnt_stats;
464
465static const struct rpc_program mnt_program = {
466 .name = "mount",
467 .number = NFS_MNT_PROGRAM,
468 .nrvers = ARRAY_SIZE(mnt_version),
469 .version = mnt_version,
470 .stats = &mnt_stats,
471};
472

source code of linux/fs/nfs/mount_clnt.c