xref: /linux/fs/lockd/clntxdr.c (revision 7f71507851fc7764b36a3221839607d3a45c2025) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/fs/lockd/clntxdr.c
4  *
5  * XDR functions to encode/decode NLM version 1 and 3 RPC
6  * arguments and results. NLM version 2 is not specified
7  * by a standard, thus it is not implemented.
8  *
9  * NLM client-side only.
10  *
11  * Copyright (C) 2010, Oracle.  All rights reserved.
12  */
13 
14 #include <linux/types.h>
15 #include <linux/sunrpc/xdr.h>
16 #include <linux/sunrpc/clnt.h>
17 #include <linux/sunrpc/stats.h>
18 #include <linux/lockd/lockd.h>
19 
20 #include <uapi/linux/nfs2.h>
21 
22 #define NLMDBG_FACILITY		NLMDBG_XDR
23 
24 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
25 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
26 #endif
27 
28 /*
29  * Declare the space requirements for NLM arguments and replies as
30  * number of 32bit-words
31  */
32 #define NLM_cookie_sz		(1+(NLM_MAXCOOKIELEN>>2))
33 #define NLM_caller_sz		(1+(NLMCLNT_OHSIZE>>2))
34 #define NLM_owner_sz		(1+(NLMCLNT_OHSIZE>>2))
35 #define NLM_fhandle_sz		(1+(NFS2_FHSIZE>>2))
36 #define NLM_lock_sz		(3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
37 #define NLM_holder_sz		(4+NLM_owner_sz)
38 
39 #define NLM_testargs_sz		(NLM_cookie_sz+1+NLM_lock_sz)
40 #define NLM_lockargs_sz		(NLM_cookie_sz+4+NLM_lock_sz)
41 #define NLM_cancargs_sz		(NLM_cookie_sz+2+NLM_lock_sz)
42 #define NLM_unlockargs_sz	(NLM_cookie_sz+NLM_lock_sz)
43 
44 #define NLM_testres_sz		(NLM_cookie_sz+1+NLM_holder_sz)
45 #define NLM_res_sz		(NLM_cookie_sz+1)
46 #define NLM_norep_sz		(0)
47 
48 
49 static s32 loff_t_to_s32(loff_t offset)
50 {
51 	s32 res;
52 
53 	if (offset >= NLM_OFFSET_MAX)
54 		res = NLM_OFFSET_MAX;
55 	else if (offset <= -NLM_OFFSET_MAX)
56 		res = -NLM_OFFSET_MAX;
57 	else
58 		res = offset;
59 	return res;
60 }
61 
62 static void nlm_compute_offsets(const struct nlm_lock *lock,
63 				u32 *l_offset, u32 *l_len)
64 {
65 	const struct file_lock *fl = &lock->fl;
66 
67 	*l_offset = loff_t_to_s32(fl->fl_start);
68 	if (fl->fl_end == OFFSET_MAX)
69 		*l_len = 0;
70 	else
71 		*l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
72 }
73 
74 /*
75  * Encode/decode NLMv3 basic data types
76  *
77  * Basic NLMv3 data types are not defined in an IETF standards
78  * document.  X/Open has a description of these data types that
79  * is useful.  See Chapter 10 of "Protocols for Interworking:
80  * XNFS, Version 3W".
81  *
82  * Not all basic data types have their own encoding and decoding
83  * functions.  For run-time efficiency, some data types are encoded
84  * or decoded inline.
85  */
86 
87 static void encode_bool(struct xdr_stream *xdr, const int value)
88 {
89 	__be32 *p;
90 
91 	p = xdr_reserve_space(xdr, 4);
92 	*p = value ? xdr_one : xdr_zero;
93 }
94 
95 static void encode_int32(struct xdr_stream *xdr, const s32 value)
96 {
97 	__be32 *p;
98 
99 	p = xdr_reserve_space(xdr, 4);
100 	*p = cpu_to_be32(value);
101 }
102 
103 /*
104  *	typedef opaque netobj<MAXNETOBJ_SZ>
105  */
106 static void encode_netobj(struct xdr_stream *xdr,
107 			  const u8 *data, const unsigned int length)
108 {
109 	__be32 *p;
110 
111 	p = xdr_reserve_space(xdr, 4 + length);
112 	xdr_encode_opaque(p, data, length);
113 }
114 
115 static int decode_netobj(struct xdr_stream *xdr,
116 			 struct xdr_netobj *obj)
117 {
118 	ssize_t ret;
119 
120 	ret = xdr_stream_decode_opaque_inline(xdr, (void *)&obj->data,
121 			XDR_MAX_NETOBJ);
122 	if (unlikely(ret < 0))
123 		return -EIO;
124 	obj->len = ret;
125 	return 0;
126 }
127 
128 /*
129  *	netobj cookie;
130  */
131 static void encode_cookie(struct xdr_stream *xdr,
132 			  const struct nlm_cookie *cookie)
133 {
134 	encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
135 }
136 
137 static int decode_cookie(struct xdr_stream *xdr,
138 			 struct nlm_cookie *cookie)
139 {
140 	u32 length;
141 	__be32 *p;
142 
143 	p = xdr_inline_decode(xdr, 4);
144 	if (unlikely(p == NULL))
145 		goto out_overflow;
146 	length = be32_to_cpup(p++);
147 	/* apparently HPUX can return empty cookies */
148 	if (length == 0)
149 		goto out_hpux;
150 	if (length > NLM_MAXCOOKIELEN)
151 		goto out_size;
152 	p = xdr_inline_decode(xdr, length);
153 	if (unlikely(p == NULL))
154 		goto out_overflow;
155 	cookie->len = length;
156 	memcpy(cookie->data, p, length);
157 	return 0;
158 out_hpux:
159 	cookie->len = 4;
160 	memset(cookie->data, 0, 4);
161 	return 0;
162 out_size:
163 	dprintk("NFS: returned cookie was too long: %u\n", length);
164 	return -EIO;
165 out_overflow:
166 	return -EIO;
167 }
168 
169 /*
170  *	netobj fh;
171  */
172 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
173 {
174 	encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
175 }
176 
177 /*
178  *	enum nlm_stats {
179  *		LCK_GRANTED = 0,
180  *		LCK_DENIED = 1,
181  *		LCK_DENIED_NOLOCKS = 2,
182  *		LCK_BLOCKED = 3,
183  *		LCK_DENIED_GRACE_PERIOD = 4
184  *	};
185  *
186  *
187  *	struct nlm_stat {
188  *		nlm_stats stat;
189  *	};
190  *
191  * NB: we don't swap bytes for the NLM status values.  The upper
192  * layers deal directly with the status value in network byte
193  * order.
194  */
195 
196 static void encode_nlm_stat(struct xdr_stream *xdr,
197 			    const __be32 stat)
198 {
199 	__be32 *p;
200 
201 	WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
202 	p = xdr_reserve_space(xdr, 4);
203 	*p = stat;
204 }
205 
206 static int decode_nlm_stat(struct xdr_stream *xdr,
207 			   __be32 *stat)
208 {
209 	__be32 *p;
210 
211 	p = xdr_inline_decode(xdr, 4);
212 	if (unlikely(p == NULL))
213 		goto out_overflow;
214 	if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
215 		goto out_enum;
216 	*stat = *p;
217 	return 0;
218 out_enum:
219 	dprintk("%s: server returned invalid nlm_stats value: %u\n",
220 		__func__, be32_to_cpup(p));
221 	return -EIO;
222 out_overflow:
223 	return -EIO;
224 }
225 
226 /*
227  *	struct nlm_holder {
228  *		bool exclusive;
229  *		int uppid;
230  *		netobj oh;
231  *		unsigned l_offset;
232  *		unsigned l_len;
233  *	};
234  */
235 static void encode_nlm_holder(struct xdr_stream *xdr,
236 			      const struct nlm_res *result)
237 {
238 	const struct nlm_lock *lock = &result->lock;
239 	u32 l_offset, l_len;
240 	__be32 *p;
241 
242 	encode_bool(xdr, lock->fl.c.flc_type == F_RDLCK);
243 	encode_int32(xdr, lock->svid);
244 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
245 
246 	p = xdr_reserve_space(xdr, 4 + 4);
247 	nlm_compute_offsets(lock, &l_offset, &l_len);
248 	*p++ = cpu_to_be32(l_offset);
249 	*p   = cpu_to_be32(l_len);
250 }
251 
252 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
253 {
254 	struct nlm_lock *lock = &result->lock;
255 	struct file_lock *fl = &lock->fl;
256 	u32 exclusive, l_offset, l_len;
257 	int error;
258 	__be32 *p;
259 	s32 end;
260 
261 	memset(lock, 0, sizeof(*lock));
262 	locks_init_lock(fl);
263 
264 	p = xdr_inline_decode(xdr, 4 + 4);
265 	if (unlikely(p == NULL))
266 		goto out_overflow;
267 	exclusive = be32_to_cpup(p++);
268 	lock->svid = be32_to_cpup(p);
269 	fl->c.flc_pid = (pid_t)lock->svid;
270 
271 	error = decode_netobj(xdr, &lock->oh);
272 	if (unlikely(error))
273 		goto out;
274 
275 	p = xdr_inline_decode(xdr, 4 + 4);
276 	if (unlikely(p == NULL))
277 		goto out_overflow;
278 
279 	fl->c.flc_flags = FL_POSIX;
280 	fl->c.flc_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
281 	l_offset = be32_to_cpup(p++);
282 	l_len = be32_to_cpup(p);
283 	end = l_offset + l_len - 1;
284 
285 	fl->fl_start = (loff_t)l_offset;
286 	if (l_len == 0 || end < 0)
287 		fl->fl_end = OFFSET_MAX;
288 	else
289 		fl->fl_end = (loff_t)end;
290 	error = 0;
291 out:
292 	return error;
293 out_overflow:
294 	return -EIO;
295 }
296 
297 /*
298  *	string caller_name<LM_MAXSTRLEN>;
299  */
300 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
301 {
302 	/* NB: client-side does not set lock->len */
303 	u32 length = strlen(name);
304 	__be32 *p;
305 
306 	p = xdr_reserve_space(xdr, 4 + length);
307 	xdr_encode_opaque(p, name, length);
308 }
309 
310 /*
311  *	struct nlm_lock {
312  *		string caller_name<LM_MAXSTRLEN>;
313  *		netobj fh;
314  *		netobj oh;
315  *		int uppid;
316  *		unsigned l_offset;
317  *		unsigned l_len;
318  *	};
319  */
320 static void encode_nlm_lock(struct xdr_stream *xdr,
321 			    const struct nlm_lock *lock)
322 {
323 	u32 l_offset, l_len;
324 	__be32 *p;
325 
326 	encode_caller_name(xdr, lock->caller);
327 	encode_fh(xdr, &lock->fh);
328 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
329 
330 	p = xdr_reserve_space(xdr, 4 + 4 + 4);
331 	*p++ = cpu_to_be32(lock->svid);
332 
333 	nlm_compute_offsets(lock, &l_offset, &l_len);
334 	*p++ = cpu_to_be32(l_offset);
335 	*p   = cpu_to_be32(l_len);
336 }
337 
338 
339 /*
340  * NLMv3 XDR encode functions
341  *
342  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
343  * "Protocols for Interworking: XNFS, Version 3W".
344  */
345 
346 /*
347  *	struct nlm_testargs {
348  *		netobj cookie;
349  *		bool exclusive;
350  *		struct nlm_lock alock;
351  *	};
352  */
353 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
354 				 struct xdr_stream *xdr,
355 				 const void *data)
356 {
357 	const struct nlm_args *args = data;
358 	const struct nlm_lock *lock = &args->lock;
359 
360 	encode_cookie(xdr, &args->cookie);
361 	encode_bool(xdr, lock->fl.c.flc_type == F_WRLCK);
362 	encode_nlm_lock(xdr, lock);
363 }
364 
365 /*
366  *	struct nlm_lockargs {
367  *		netobj cookie;
368  *		bool block;
369  *		bool exclusive;
370  *		struct nlm_lock alock;
371  *		bool reclaim;
372  *		int state;
373  *	};
374  */
375 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
376 				 struct xdr_stream *xdr,
377 				 const void *data)
378 {
379 	const struct nlm_args *args = data;
380 	const struct nlm_lock *lock = &args->lock;
381 
382 	encode_cookie(xdr, &args->cookie);
383 	encode_bool(xdr, args->block);
384 	encode_bool(xdr, lock->fl.c.flc_type == F_WRLCK);
385 	encode_nlm_lock(xdr, lock);
386 	encode_bool(xdr, args->reclaim);
387 	encode_int32(xdr, args->state);
388 }
389 
390 /*
391  *	struct nlm_cancargs {
392  *		netobj cookie;
393  *		bool block;
394  *		bool exclusive;
395  *		struct nlm_lock alock;
396  *	};
397  */
398 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
399 				 struct xdr_stream *xdr,
400 				 const void *data)
401 {
402 	const struct nlm_args *args = data;
403 	const struct nlm_lock *lock = &args->lock;
404 
405 	encode_cookie(xdr, &args->cookie);
406 	encode_bool(xdr, args->block);
407 	encode_bool(xdr, lock->fl.c.flc_type == F_WRLCK);
408 	encode_nlm_lock(xdr, lock);
409 }
410 
411 /*
412  *	struct nlm_unlockargs {
413  *		netobj cookie;
414  *		struct nlm_lock alock;
415  *	};
416  */
417 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
418 				   struct xdr_stream *xdr,
419 				   const void *data)
420 {
421 	const struct nlm_args *args = data;
422 	const struct nlm_lock *lock = &args->lock;
423 
424 	encode_cookie(xdr, &args->cookie);
425 	encode_nlm_lock(xdr, lock);
426 }
427 
428 /*
429  *	struct nlm_res {
430  *		netobj cookie;
431  *		nlm_stat stat;
432  *	};
433  */
434 static void nlm_xdr_enc_res(struct rpc_rqst *req,
435 			    struct xdr_stream *xdr,
436 			    const void *data)
437 {
438 	const struct nlm_res *result = data;
439 
440 	encode_cookie(xdr, &result->cookie);
441 	encode_nlm_stat(xdr, result->status);
442 }
443 
444 /*
445  *	union nlm_testrply switch (nlm_stats stat) {
446  *	case LCK_DENIED:
447  *		struct nlm_holder holder;
448  *	default:
449  *		void;
450  *	};
451  *
452  *	struct nlm_testres {
453  *		netobj cookie;
454  *		nlm_testrply test_stat;
455  *	};
456  */
457 static void encode_nlm_testrply(struct xdr_stream *xdr,
458 				const struct nlm_res *result)
459 {
460 	if (result->status == nlm_lck_denied)
461 		encode_nlm_holder(xdr, result);
462 }
463 
464 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
465 				struct xdr_stream *xdr,
466 				const void *data)
467 {
468 	const struct nlm_res *result = data;
469 
470 	encode_cookie(xdr, &result->cookie);
471 	encode_nlm_stat(xdr, result->status);
472 	encode_nlm_testrply(xdr, result);
473 }
474 
475 
476 /*
477  * NLMv3 XDR decode functions
478  *
479  * NLMv3 result types are defined in Chapter 10 of The Open Group's
480  * "Protocols for Interworking: XNFS, Version 3W".
481  */
482 
483 /*
484  *	union nlm_testrply switch (nlm_stats stat) {
485  *	case LCK_DENIED:
486  *		struct nlm_holder holder;
487  *	default:
488  *		void;
489  *	};
490  *
491  *	struct nlm_testres {
492  *		netobj cookie;
493  *		nlm_testrply test_stat;
494  *	};
495  */
496 static int decode_nlm_testrply(struct xdr_stream *xdr,
497 			       struct nlm_res *result)
498 {
499 	int error;
500 
501 	error = decode_nlm_stat(xdr, &result->status);
502 	if (unlikely(error))
503 		goto out;
504 	if (result->status == nlm_lck_denied)
505 		error = decode_nlm_holder(xdr, result);
506 out:
507 	return error;
508 }
509 
510 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
511 			       struct xdr_stream *xdr,
512 			       void *data)
513 {
514 	struct nlm_res *result = data;
515 	int error;
516 
517 	error = decode_cookie(xdr, &result->cookie);
518 	if (unlikely(error))
519 		goto out;
520 	error = decode_nlm_testrply(xdr, result);
521 out:
522 	return error;
523 }
524 
525 /*
526  *	struct nlm_res {
527  *		netobj cookie;
528  *		nlm_stat stat;
529  *	};
530  */
531 static int nlm_xdr_dec_res(struct rpc_rqst *req,
532 			   struct xdr_stream *xdr,
533 			   void *data)
534 {
535 	struct nlm_res *result = data;
536 	int error;
537 
538 	error = decode_cookie(xdr, &result->cookie);
539 	if (unlikely(error))
540 		goto out;
541 	error = decode_nlm_stat(xdr, &result->status);
542 out:
543 	return error;
544 }
545 
546 
547 /*
548  * For NLM, a void procedure really returns nothing
549  */
550 #define nlm_xdr_dec_norep	NULL
551 
552 #define PROC(proc, argtype, restype)	\
553 [NLMPROC_##proc] = {							\
554 	.p_proc      = NLMPROC_##proc,					\
555 	.p_encode    = nlm_xdr_enc_##argtype,		\
556 	.p_decode    = nlm_xdr_dec_##restype,				\
557 	.p_arglen    = NLM_##argtype##_sz,				\
558 	.p_replen    = NLM_##restype##_sz,				\
559 	.p_statidx   = NLMPROC_##proc,					\
560 	.p_name      = #proc,						\
561 	}
562 
563 static const struct rpc_procinfo nlm_procedures[] = {
564 	PROC(TEST,		testargs,	testres),
565 	PROC(LOCK,		lockargs,	res),
566 	PROC(CANCEL,		cancargs,	res),
567 	PROC(UNLOCK,		unlockargs,	res),
568 	PROC(GRANTED,		testargs,	res),
569 	PROC(TEST_MSG,		testargs,	norep),
570 	PROC(LOCK_MSG,		lockargs,	norep),
571 	PROC(CANCEL_MSG,	cancargs,	norep),
572 	PROC(UNLOCK_MSG,	unlockargs,	norep),
573 	PROC(GRANTED_MSG,	testargs,	norep),
574 	PROC(TEST_RES,		testres,	norep),
575 	PROC(LOCK_RES,		res,		norep),
576 	PROC(CANCEL_RES,	res,		norep),
577 	PROC(UNLOCK_RES,	res,		norep),
578 	PROC(GRANTED_RES,	res,		norep),
579 };
580 
581 static unsigned int nlm_version1_counts[ARRAY_SIZE(nlm_procedures)];
582 static const struct rpc_version	nlm_version1 = {
583 	.number		= 1,
584 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
585 	.procs		= nlm_procedures,
586 	.counts		= nlm_version1_counts,
587 };
588 
589 static unsigned int nlm_version3_counts[ARRAY_SIZE(nlm_procedures)];
590 static const struct rpc_version	nlm_version3 = {
591 	.number		= 3,
592 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
593 	.procs		= nlm_procedures,
594 	.counts		= nlm_version3_counts,
595 };
596 
597 static const struct rpc_version	*nlm_versions[] = {
598 	[1] = &nlm_version1,
599 	[3] = &nlm_version3,
600 #ifdef CONFIG_LOCKD_V4
601 	[4] = &nlm_version4,
602 #endif
603 };
604 
605 static struct rpc_stat		nlm_rpc_stats;
606 
607 const struct rpc_program	nlm_program = {
608 	.name		= "lockd",
609 	.number		= NLM_PROGRAM,
610 	.nrvers		= ARRAY_SIZE(nlm_versions),
611 	.version	= nlm_versions,
612 	.stats		= &nlm_rpc_stats,
613 };
614