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
131struct 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 */
146int 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	= (struct sockaddr *)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	}
213out:
214	return status;
215
216out_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
221out_call_err:
222	dprintk("NFS: MNT request failed, status=%d\n", status);
223	goto out;
224
225out_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 */
238void 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	= (struct sockaddr *)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
290out_clnt_err:
291	dprintk("NFS: failed to create UMNT RPC client, status=%ld\n",
292			PTR_ERR(clnt));
293	return;
294
295out_call_err:
296	dprintk("NFS: UMNT request failed, status=%d\n", status);
297}
298
299/*
300 * XDR encode/decode functions for MOUNT
301 */
302
303static 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
312static 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 */
327static 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
350static 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
364static 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
377static 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
400static 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
423static 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
457static 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
475static 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
494static 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
513static unsigned int mnt_counts[ARRAY_SIZE(mnt_procedures)];
514static 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
521static unsigned int mnt3_counts[ARRAY_SIZE(mnt3_procedures)];
522static 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
529static const struct rpc_version *mnt_version[] = {
530	NULL,
531	&mnt_version1,
532	NULL,
533	&mnt_version3,
534};
535
536static struct rpc_stat mnt_stats;
537
538static 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