xref: /linux/fs/lockd/clntxdr.c (revision 5ea5880764cbb164afb17a62e76ca75dc371409d) 
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 
19 #include "lockd.h"
20 
21 #include <uapi/linux/nfs2.h>
22 
23 #define NLMDBG_FACILITY		NLMDBG_XDR
24 
25 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
26 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
27 #endif
28 
29 /*
30  * Declare the space requirements for NLM arguments and replies as
31  * number of 32bit-words
32  */
33 #define NLM_cookie_sz		(1+(NLM_MAXCOOKIELEN>>2))
34 #define NLM_caller_sz		(1+(NLMCLNT_OHSIZE>>2))
35 #define NLM_owner_sz		(1+(NLMCLNT_OHSIZE>>2))
36 #define NLM_fhandle_sz		(1+(NFS2_FHSIZE>>2))
37 #define NLM_lock_sz		(3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
38 #define NLM_holder_sz		(4+NLM_owner_sz)
39 
40 #define NLM_testargs_sz		(NLM_cookie_sz+1+NLM_lock_sz)
41 #define NLM_lockargs_sz		(NLM_cookie_sz+4+NLM_lock_sz)
42 #define NLM_cancargs_sz		(NLM_cookie_sz+2+NLM_lock_sz)
43 #define NLM_unlockargs_sz	(NLM_cookie_sz+NLM_lock_sz)
44 
45 #define NLM_testres_sz		(NLM_cookie_sz+1+NLM_holder_sz)
46 #define NLM_res_sz		(NLM_cookie_sz+1)
47 #define NLM_norep_sz		(0)
48 
49 
50 static s32 loff_t_to_s32(loff_t offset)
51 {
52 	s32 res;
53 
54 	if (offset >= NLM_OFFSET_MAX)
55 		res = NLM_OFFSET_MAX;
56 	else if (offset <= -NLM_OFFSET_MAX)
57 		res = -NLM_OFFSET_MAX;
58 	else
59 		res = offset;
60 	return res;
61 }
62 
63 static void nlm_compute_offsets(const struct nlm_lock *lock,
64 				u32 *l_offset, u32 *l_len)
65 {
66 	const struct file_lock *fl = &lock->fl;
67 
68 	*l_offset = loff_t_to_s32(fl->fl_start);
69 	if (fl->fl_end == OFFSET_MAX)
70 		*l_len = 0;
71 	else
72 		*l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
73 }
74 
75 /*
76  * Encode/decode NLMv3 basic data types
77  *
78  * Basic NLMv3 data types are not defined in an IETF standards
79  * document.  X/Open has a description of these data types that
80  * is useful.  See Chapter 10 of "Protocols for Interworking:
81  * XNFS, Version 3W".
82  *
83  * Not all basic data types have their own encoding and decoding
84  * functions.  For run-time efficiency, some data types are encoded
85  * or decoded inline.
86  */
87 
88 static void encode_bool(struct xdr_stream *xdr, const int value)
89 {
90 	__be32 *p;
91 
92 	p = xdr_reserve_space(xdr, 4);
93 	*p = value ? xdr_one : xdr_zero;
94 }
95 
96 static void encode_int32(struct xdr_stream *xdr, const s32 value)
97 {
98 	__be32 *p;
99 
100 	p = xdr_reserve_space(xdr, 4);
101 	*p = cpu_to_be32(value);
102 }
103 
104 /*
105  *	typedef opaque netobj<MAXNETOBJ_SZ>
106  */
107 static void encode_netobj(struct xdr_stream *xdr,
108 			  const u8 *data, const unsigned int length)
109 {
110 	__be32 *p;
111 
112 	p = xdr_reserve_space(xdr, 4 + length);
113 	xdr_encode_opaque(p, data, length);
114 }
115 
116 static int decode_netobj(struct xdr_stream *xdr,
117 			 struct xdr_netobj *obj)
118 {
119 	ssize_t ret;
120 
121 	ret = xdr_stream_decode_opaque_inline(xdr, (void *)&obj->data,
122 			XDR_MAX_NETOBJ);
123 	if (unlikely(ret < 0))
124 		return -EIO;
125 	obj->len = ret;
126 	return 0;
127 }
128 
129 /*
130  *	netobj cookie;
131  */
132 static void encode_cookie(struct xdr_stream *xdr,
133 			  const struct nlm_cookie *cookie)
134 {
135 	encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
136 }
137 
138 static int decode_cookie(struct xdr_stream *xdr,
139 			 struct nlm_cookie *cookie)
140 {
141 	u32 length;
142 	__be32 *p;
143 
144 	p = xdr_inline_decode(xdr, 4);
145 	if (unlikely(p == NULL))
146 		goto out_overflow;
147 	length = be32_to_cpup(p++);
148 	/* apparently HPUX can return empty cookies */
149 	if (length == 0)
150 		goto out_hpux;
151 	if (length > NLM_MAXCOOKIELEN)
152 		goto out_size;
153 	p = xdr_inline_decode(xdr, length);
154 	if (unlikely(p == NULL))
155 		goto out_overflow;
156 	cookie->len = length;
157 	memcpy(cookie->data, p, length);
158 	return 0;
159 out_hpux:
160 	cookie->len = 4;
161 	memset(cookie->data, 0, 4);
162 	return 0;
163 out_size:
164 	dprintk("NFS: returned cookie was too long: %u\n", length);
165 	return -EIO;
166 out_overflow:
167 	return -EIO;
168 }
169 
170 /*
171  *	netobj fh;
172  */
173 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
174 {
175 	encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
176 }
177 
178 /*
179  *	enum nlm_stats {
180  *		LCK_GRANTED = 0,
181  *		LCK_DENIED = 1,
182  *		LCK_DENIED_NOLOCKS = 2,
183  *		LCK_BLOCKED = 3,
184  *		LCK_DENIED_GRACE_PERIOD = 4
185  *	};
186  *
187  *
188  *	struct nlm_stat {
189  *		nlm_stats stat;
190  *	};
191  *
192  * NB: we don't swap bytes for the NLM status values.  The upper
193  * layers deal directly with the status value in network byte
194  * order.
195  */
196 
197 static void encode_nlm_stat(struct xdr_stream *xdr,
198 			    const __be32 stat)
199 {
200 	__be32 *p;
201 
202 	WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
203 	p = xdr_reserve_space(xdr, 4);
204 	*p = stat;
205 }
206 
207 static int decode_nlm_stat(struct xdr_stream *xdr,
208 			   __be32 *stat)
209 {
210 	__be32 *p;
211 
212 	p = xdr_inline_decode(xdr, 4);
213 	if (unlikely(p == NULL))
214 		goto out_overflow;
215 	if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
216 		goto out_enum;
217 	*stat = *p;
218 	return 0;
219 out_enum:
220 	dprintk("%s: server returned invalid nlm_stats value: %u\n",
221 		__func__, be32_to_cpup(p));
222 	return -EIO;
223 out_overflow:
224 	return -EIO;
225 }
226 
227 /*
228  *	struct nlm_holder {
229  *		bool exclusive;
230  *		int uppid;
231  *		netobj oh;
232  *		unsigned l_offset;
233  *		unsigned l_len;
234  *	};
235  */
236 static void encode_nlm_holder(struct xdr_stream *xdr,
237 			      const struct nlm_res *result)
238 {
239 	const struct nlm_lock *lock = &result->lock;
240 	u32 l_offset, l_len;
241 	__be32 *p;
242 
243 	encode_bool(xdr, lock->fl.c.flc_type == F_RDLCK);
244 	encode_int32(xdr, lock->svid);
245 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
246 
247 	p = xdr_reserve_space(xdr, 4 + 4);
248 	nlm_compute_offsets(lock, &l_offset, &l_len);
249 	*p++ = cpu_to_be32(l_offset);
250 	*p   = cpu_to_be32(l_len);
251 }
252 
253 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
254 {
255 	struct nlm_lock *lock = &result->lock;
256 	struct file_lock *fl = &lock->fl;
257 	u32 exclusive, l_offset, l_len;
258 	int error;
259 	__be32 *p;
260 	s32 end;
261 
262 	memset(lock, 0, sizeof(*lock));
263 	locks_init_lock(fl);
264 
265 	p = xdr_inline_decode(xdr, 4 + 4);
266 	if (unlikely(p == NULL))
267 		goto out_overflow;
268 	exclusive = be32_to_cpup(p++);
269 	lock->svid = be32_to_cpup(p);
270 	fl->c.flc_pid = (pid_t)lock->svid;
271 
272 	error = decode_netobj(xdr, &lock->oh);
273 	if (unlikely(error))
274 		goto out;
275 
276 	p = xdr_inline_decode(xdr, 4 + 4);
277 	if (unlikely(p == NULL))
278 		goto out_overflow;
279 
280 	fl->c.flc_flags = FL_POSIX;
281 	fl->c.flc_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
282 	l_offset = be32_to_cpup(p++);
283 	l_len = be32_to_cpup(p);
284 	end = l_offset + l_len - 1;
285 
286 	fl->fl_start = (loff_t)l_offset;
287 	if (l_len == 0 || end < 0)
288 		fl->fl_end = OFFSET_MAX;
289 	else
290 		fl->fl_end = (loff_t)end;
291 	error = 0;
292 out:
293 	return error;
294 out_overflow:
295 	return -EIO;
296 }
297 
298 /*
299  *	string caller_name<LM_MAXSTRLEN>;
300  */
301 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
302 {
303 	/* NB: client-side does not set lock->len */
304 	u32 length = strlen(name);
305 	__be32 *p;
306 
307 	p = xdr_reserve_space(xdr, 4 + length);
308 	xdr_encode_opaque(p, name, length);
309 }
310 
311 /*
312  *	struct nlm_lock {
313  *		string caller_name<LM_MAXSTRLEN>;
314  *		netobj fh;
315  *		netobj oh;
316  *		int uppid;
317  *		unsigned l_offset;
318  *		unsigned l_len;
319  *	};
320  */
321 static void encode_nlm_lock(struct xdr_stream *xdr,
322 			    const struct nlm_lock *lock)
323 {
324 	u32 l_offset, l_len;
325 	__be32 *p;
326 
327 	encode_caller_name(xdr, lock->caller);
328 	encode_fh(xdr, &lock->fh);
329 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
330 
331 	p = xdr_reserve_space(xdr, 4 + 4 + 4);
332 	*p++ = cpu_to_be32(lock->svid);
333 
334 	nlm_compute_offsets(lock, &l_offset, &l_len);
335 	*p++ = cpu_to_be32(l_offset);
336 	*p   = cpu_to_be32(l_len);
337 }
338 
339 
340 /*
341  * NLMv3 XDR encode functions
342  *
343  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
344  * "Protocols for Interworking: XNFS, Version 3W".
345  */
346 
347 /*
348  *	struct nlm_testargs {
349  *		netobj cookie;
350  *		bool exclusive;
351  *		struct nlm_lock alock;
352  *	};
353  */
354 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
355 				 struct xdr_stream *xdr,
356 				 const void *data)
357 {
358 	const struct nlm_args *args = data;
359 	const struct nlm_lock *lock = &args->lock;
360 
361 	encode_cookie(xdr, &args->cookie);
362 	encode_bool(xdr, lock->fl.c.flc_type == F_WRLCK);
363 	encode_nlm_lock(xdr, lock);
364 }
365 
366 /*
367  *	struct nlm_lockargs {
368  *		netobj cookie;
369  *		bool block;
370  *		bool exclusive;
371  *		struct nlm_lock alock;
372  *		bool reclaim;
373  *		int state;
374  *	};
375  */
376 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
377 				 struct xdr_stream *xdr,
378 				 const void *data)
379 {
380 	const struct nlm_args *args = data;
381 	const struct nlm_lock *lock = &args->lock;
382 
383 	encode_cookie(xdr, &args->cookie);
384 	encode_bool(xdr, args->block);
385 	encode_bool(xdr, lock->fl.c.flc_type == F_WRLCK);
386 	encode_nlm_lock(xdr, lock);
387 	encode_bool(xdr, args->reclaim);
388 	encode_int32(xdr, args->state);
389 }
390 
391 /*
392  *	struct nlm_cancargs {
393  *		netobj cookie;
394  *		bool block;
395  *		bool exclusive;
396  *		struct nlm_lock alock;
397  *	};
398  */
399 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
400 				 struct xdr_stream *xdr,
401 				 const void *data)
402 {
403 	const struct nlm_args *args = data;
404 	const struct nlm_lock *lock = &args->lock;
405 
406 	encode_cookie(xdr, &args->cookie);
407 	encode_bool(xdr, args->block);
408 	encode_bool(xdr, lock->fl.c.flc_type == F_WRLCK);
409 	encode_nlm_lock(xdr, lock);
410 }
411 
412 /*
413  *	struct nlm_unlockargs {
414  *		netobj cookie;
415  *		struct nlm_lock alock;
416  *	};
417  */
418 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
419 				   struct xdr_stream *xdr,
420 				   const void *data)
421 {
422 	const struct nlm_args *args = data;
423 	const struct nlm_lock *lock = &args->lock;
424 
425 	encode_cookie(xdr, &args->cookie);
426 	encode_nlm_lock(xdr, lock);
427 }
428 
429 /*
430  *	struct nlm_res {
431  *		netobj cookie;
432  *		nlm_stat stat;
433  *	};
434  */
435 static void nlm_xdr_enc_res(struct rpc_rqst *req,
436 			    struct xdr_stream *xdr,
437 			    const void *data)
438 {
439 	const struct nlm_res *result = data;
440 
441 	encode_cookie(xdr, &result->cookie);
442 	encode_nlm_stat(xdr, result->status);
443 }
444 
445 /*
446  *	union nlm_testrply switch (nlm_stats stat) {
447  *	case LCK_DENIED:
448  *		struct nlm_holder holder;
449  *	default:
450  *		void;
451  *	};
452  *
453  *	struct nlm_testres {
454  *		netobj cookie;
455  *		nlm_testrply test_stat;
456  *	};
457  */
458 static void encode_nlm_testrply(struct xdr_stream *xdr,
459 				const struct nlm_res *result)
460 {
461 	if (result->status == nlm_lck_denied)
462 		encode_nlm_holder(xdr, result);
463 }
464 
465 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
466 				struct xdr_stream *xdr,
467 				const void *data)
468 {
469 	const struct nlm_res *result = data;
470 
471 	encode_cookie(xdr, &result->cookie);
472 	encode_nlm_stat(xdr, result->status);
473 	encode_nlm_testrply(xdr, result);
474 }
475 
476 
477 /*
478  * NLMv3 XDR decode functions
479  *
480  * NLMv3 result types are defined in Chapter 10 of The Open Group's
481  * "Protocols for Interworking: XNFS, Version 3W".
482  */
483 
484 /*
485  *	union nlm_testrply switch (nlm_stats stat) {
486  *	case LCK_DENIED:
487  *		struct nlm_holder holder;
488  *	default:
489  *		void;
490  *	};
491  *
492  *	struct nlm_testres {
493  *		netobj cookie;
494  *		nlm_testrply test_stat;
495  *	};
496  */
497 static int decode_nlm_testrply(struct xdr_stream *xdr,
498 			       struct nlm_res *result)
499 {
500 	int error;
501 
502 	error = decode_nlm_stat(xdr, &result->status);
503 	if (unlikely(error))
504 		goto out;
505 	if (result->status == nlm_lck_denied)
506 		error = decode_nlm_holder(xdr, result);
507 out:
508 	return error;
509 }
510 
511 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
512 			       struct xdr_stream *xdr,
513 			       void *data)
514 {
515 	struct nlm_res *result = data;
516 	int error;
517 
518 	error = decode_cookie(xdr, &result->cookie);
519 	if (unlikely(error))
520 		goto out;
521 	error = decode_nlm_testrply(xdr, result);
522 out:
523 	return error;
524 }
525 
526 /*
527  *	struct nlm_res {
528  *		netobj cookie;
529  *		nlm_stat stat;
530  *	};
531  */
532 static int nlm_xdr_dec_res(struct rpc_rqst *req,
533 			   struct xdr_stream *xdr,
534 			   void *data)
535 {
536 	struct nlm_res *result = data;
537 	int error;
538 
539 	error = decode_cookie(xdr, &result->cookie);
540 	if (unlikely(error))
541 		goto out;
542 	error = decode_nlm_stat(xdr, &result->status);
543 out:
544 	return error;
545 }
546 
547 
548 /*
549  * For NLM, a void procedure really returns nothing
550  */
551 #define nlm_xdr_dec_norep	NULL
552 
553 #define PROC(proc, argtype, restype)	\
554 [NLMPROC_##proc] = {							\
555 	.p_proc      = NLMPROC_##proc,					\
556 	.p_encode    = nlm_xdr_enc_##argtype,		\
557 	.p_decode    = nlm_xdr_dec_##restype,				\
558 	.p_arglen    = NLM_##argtype##_sz,				\
559 	.p_replen    = NLM_##restype##_sz,				\
560 	.p_statidx   = NLMPROC_##proc,					\
561 	.p_name      = #proc,						\
562 	}
563 
564 static const struct rpc_procinfo nlm_procedures[] = {
565 	PROC(TEST,		testargs,	testres),
566 	PROC(LOCK,		lockargs,	res),
567 	PROC(CANCEL,		cancargs,	res),
568 	PROC(UNLOCK,		unlockargs,	res),
569 	PROC(GRANTED,		testargs,	res),
570 	PROC(TEST_MSG,		testargs,	norep),
571 	PROC(LOCK_MSG,		lockargs,	norep),
572 	PROC(CANCEL_MSG,	cancargs,	norep),
573 	PROC(UNLOCK_MSG,	unlockargs,	norep),
574 	PROC(GRANTED_MSG,	testargs,	norep),
575 	PROC(TEST_RES,		testres,	norep),
576 	PROC(LOCK_RES,		res,		norep),
577 	PROC(CANCEL_RES,	res,		norep),
578 	PROC(UNLOCK_RES,	res,		norep),
579 	PROC(GRANTED_RES,	res,		norep),
580 };
581 
582 static unsigned int nlm_version1_counts[ARRAY_SIZE(nlm_procedures)];
583 static const struct rpc_version	nlm_version1 = {
584 	.number		= 1,
585 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
586 	.procs		= nlm_procedures,
587 	.counts		= nlm_version1_counts,
588 };
589 
590 static unsigned int nlm_version3_counts[ARRAY_SIZE(nlm_procedures)];
591 static const struct rpc_version	nlm_version3 = {
592 	.number		= 3,
593 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
594 	.procs		= nlm_procedures,
595 	.counts		= nlm_version3_counts,
596 };
597 
598 static const struct rpc_version	*nlm_versions[] = {
599 	[1] = &nlm_version1,
600 	[3] = &nlm_version3,
601 #ifdef CONFIG_LOCKD_V4
602 	[4] = &nlm_version4,
603 #endif
604 };
605 
606 static struct rpc_stat		nlm_rpc_stats;
607 
608 const struct rpc_program	nlm_program = {
609 	.name		= "lockd",
610 	.number		= NLM_PROGRAM,
611 	.nrvers		= ARRAY_SIZE(nlm_versions),
612 	.version	= nlm_versions,
613 	.stats		= &nlm_rpc_stats,
614 };
615