xref: /linux/fs/lockd/clntxdr.c (revision 2da68a77) 
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/fs/lockd/clntxdr.c
4  *
5  * XDR functions to encode/decode NLM version 3 RPC arguments and results.
6  * NLM version 3 is backwards compatible with NLM versions 1 and 2.
7  *
8  * NLM client-side only.
9  *
10  * Copyright (C) 2010, Oracle.  All rights reserved.
11  */
12 
13 #include <linux/types.h>
14 #include <linux/sunrpc/xdr.h>
15 #include <linux/sunrpc/clnt.h>
16 #include <linux/sunrpc/stats.h>
17 #include <linux/lockd/lockd.h>
18 
19 #include <uapi/linux/nfs2.h>
20 
21 #define NLMDBG_FACILITY		NLMDBG_XDR
22 
23 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
24 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
25 #endif
26 
27 /*
28  * Declare the space requirements for NLM arguments and replies as
29  * number of 32bit-words
30  */
31 #define NLM_cookie_sz		(1+(NLM_MAXCOOKIELEN>>2))
32 #define NLM_caller_sz		(1+(NLMCLNT_OHSIZE>>2))
33 #define NLM_owner_sz		(1+(NLMCLNT_OHSIZE>>2))
34 #define NLM_fhandle_sz		(1+(NFS2_FHSIZE>>2))
35 #define NLM_lock_sz		(3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
36 #define NLM_holder_sz		(4+NLM_owner_sz)
37 
38 #define NLM_testargs_sz		(NLM_cookie_sz+1+NLM_lock_sz)
39 #define NLM_lockargs_sz		(NLM_cookie_sz+4+NLM_lock_sz)
40 #define NLM_cancargs_sz		(NLM_cookie_sz+2+NLM_lock_sz)
41 #define NLM_unlockargs_sz	(NLM_cookie_sz+NLM_lock_sz)
42 
43 #define NLM_testres_sz		(NLM_cookie_sz+1+NLM_holder_sz)
44 #define NLM_res_sz		(NLM_cookie_sz+1)
45 #define NLM_norep_sz		(0)
46 
47 
48 static s32 loff_t_to_s32(loff_t offset)
49 {
50 	s32 res;
51 
52 	if (offset >= NLM_OFFSET_MAX)
53 		res = NLM_OFFSET_MAX;
54 	else if (offset <= -NLM_OFFSET_MAX)
55 		res = -NLM_OFFSET_MAX;
56 	else
57 		res = offset;
58 	return res;
59 }
60 
61 static void nlm_compute_offsets(const struct nlm_lock *lock,
62 				u32 *l_offset, u32 *l_len)
63 {
64 	const struct file_lock *fl = &lock->fl;
65 
66 	*l_offset = loff_t_to_s32(fl->fl_start);
67 	if (fl->fl_end == OFFSET_MAX)
68 		*l_len = 0;
69 	else
70 		*l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
71 }
72 
73 /*
74  * Encode/decode NLMv3 basic data types
75  *
76  * Basic NLMv3 data types are not defined in an IETF standards
77  * document.  X/Open has a description of these data types that
78  * is useful.  See Chapter 10 of "Protocols for Interworking:
79  * XNFS, Version 3W".
80  *
81  * Not all basic data types have their own encoding and decoding
82  * functions.  For run-time efficiency, some data types are encoded
83  * or decoded inline.
84  */
85 
86 static void encode_bool(struct xdr_stream *xdr, const int value)
87 {
88 	__be32 *p;
89 
90 	p = xdr_reserve_space(xdr, 4);
91 	*p = value ? xdr_one : xdr_zero;
92 }
93 
94 static void encode_int32(struct xdr_stream *xdr, const s32 value)
95 {
96 	__be32 *p;
97 
98 	p = xdr_reserve_space(xdr, 4);
99 	*p = cpu_to_be32(value);
100 }
101 
102 /*
103  *	typedef opaque netobj<MAXNETOBJ_SZ>
104  */
105 static void encode_netobj(struct xdr_stream *xdr,
106 			  const u8 *data, const unsigned int length)
107 {
108 	__be32 *p;
109 
110 	p = xdr_reserve_space(xdr, 4 + length);
111 	xdr_encode_opaque(p, data, length);
112 }
113 
114 static int decode_netobj(struct xdr_stream *xdr,
115 			 struct xdr_netobj *obj)
116 {
117 	ssize_t ret;
118 
119 	ret = xdr_stream_decode_opaque_inline(xdr, (void *)&obj->data,
120 			XDR_MAX_NETOBJ);
121 	if (unlikely(ret < 0))
122 		return -EIO;
123 	obj->len = ret;
124 	return 0;
125 }
126 
127 /*
128  *	netobj cookie;
129  */
130 static void encode_cookie(struct xdr_stream *xdr,
131 			  const struct nlm_cookie *cookie)
132 {
133 	encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
134 }
135 
136 static int decode_cookie(struct xdr_stream *xdr,
137 			 struct nlm_cookie *cookie)
138 {
139 	u32 length;
140 	__be32 *p;
141 
142 	p = xdr_inline_decode(xdr, 4);
143 	if (unlikely(p == NULL))
144 		goto out_overflow;
145 	length = be32_to_cpup(p++);
146 	/* apparently HPUX can return empty cookies */
147 	if (length == 0)
148 		goto out_hpux;
149 	if (length > NLM_MAXCOOKIELEN)
150 		goto out_size;
151 	p = xdr_inline_decode(xdr, length);
152 	if (unlikely(p == NULL))
153 		goto out_overflow;
154 	cookie->len = length;
155 	memcpy(cookie->data, p, length);
156 	return 0;
157 out_hpux:
158 	cookie->len = 4;
159 	memset(cookie->data, 0, 4);
160 	return 0;
161 out_size:
162 	dprintk("NFS: returned cookie was too long: %u\n", length);
163 	return -EIO;
164 out_overflow:
165 	return -EIO;
166 }
167 
168 /*
169  *	netobj fh;
170  */
171 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
172 {
173 	encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
174 }
175 
176 /*
177  *	enum nlm_stats {
178  *		LCK_GRANTED = 0,
179  *		LCK_DENIED = 1,
180  *		LCK_DENIED_NOLOCKS = 2,
181  *		LCK_BLOCKED = 3,
182  *		LCK_DENIED_GRACE_PERIOD = 4
183  *	};
184  *
185  *
186  *	struct nlm_stat {
187  *		nlm_stats stat;
188  *	};
189  *
190  * NB: we don't swap bytes for the NLM status values.  The upper
191  * layers deal directly with the status value in network byte
192  * order.
193  */
194 
195 static void encode_nlm_stat(struct xdr_stream *xdr,
196 			    const __be32 stat)
197 {
198 	__be32 *p;
199 
200 	WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
201 	p = xdr_reserve_space(xdr, 4);
202 	*p = stat;
203 }
204 
205 static int decode_nlm_stat(struct xdr_stream *xdr,
206 			   __be32 *stat)
207 {
208 	__be32 *p;
209 
210 	p = xdr_inline_decode(xdr, 4);
211 	if (unlikely(p == NULL))
212 		goto out_overflow;
213 	if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
214 		goto out_enum;
215 	*stat = *p;
216 	return 0;
217 out_enum:
218 	dprintk("%s: server returned invalid nlm_stats value: %u\n",
219 		__func__, be32_to_cpup(p));
220 	return -EIO;
221 out_overflow:
222 	return -EIO;
223 }
224 
225 /*
226  *	struct nlm_holder {
227  *		bool exclusive;
228  *		int uppid;
229  *		netobj oh;
230  *		unsigned l_offset;
231  *		unsigned l_len;
232  *	};
233  */
234 static void encode_nlm_holder(struct xdr_stream *xdr,
235 			      const struct nlm_res *result)
236 {
237 	const struct nlm_lock *lock = &result->lock;
238 	u32 l_offset, l_len;
239 	__be32 *p;
240 
241 	encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
242 	encode_int32(xdr, lock->svid);
243 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
244 
245 	p = xdr_reserve_space(xdr, 4 + 4);
246 	nlm_compute_offsets(lock, &l_offset, &l_len);
247 	*p++ = cpu_to_be32(l_offset);
248 	*p   = cpu_to_be32(l_len);
249 }
250 
251 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
252 {
253 	struct nlm_lock *lock = &result->lock;
254 	struct file_lock *fl = &lock->fl;
255 	u32 exclusive, l_offset, l_len;
256 	int error;
257 	__be32 *p;
258 	s32 end;
259 
260 	memset(lock, 0, sizeof(*lock));
261 	locks_init_lock(fl);
262 
263 	p = xdr_inline_decode(xdr, 4 + 4);
264 	if (unlikely(p == NULL))
265 		goto out_overflow;
266 	exclusive = be32_to_cpup(p++);
267 	lock->svid = be32_to_cpup(p);
268 	fl->fl_pid = (pid_t)lock->svid;
269 
270 	error = decode_netobj(xdr, &lock->oh);
271 	if (unlikely(error))
272 		goto out;
273 
274 	p = xdr_inline_decode(xdr, 4 + 4);
275 	if (unlikely(p == NULL))
276 		goto out_overflow;
277 
278 	fl->fl_flags = FL_POSIX;
279 	fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
280 	l_offset = be32_to_cpup(p++);
281 	l_len = be32_to_cpup(p);
282 	end = l_offset + l_len - 1;
283 
284 	fl->fl_start = (loff_t)l_offset;
285 	if (l_len == 0 || end < 0)
286 		fl->fl_end = OFFSET_MAX;
287 	else
288 		fl->fl_end = (loff_t)end;
289 	error = 0;
290 out:
291 	return error;
292 out_overflow:
293 	return -EIO;
294 }
295 
296 /*
297  *	string caller_name<LM_MAXSTRLEN>;
298  */
299 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
300 {
301 	/* NB: client-side does not set lock->len */
302 	u32 length = strlen(name);
303 	__be32 *p;
304 
305 	p = xdr_reserve_space(xdr, 4 + length);
306 	xdr_encode_opaque(p, name, length);
307 }
308 
309 /*
310  *	struct nlm_lock {
311  *		string caller_name<LM_MAXSTRLEN>;
312  *		netobj fh;
313  *		netobj oh;
314  *		int uppid;
315  *		unsigned l_offset;
316  *		unsigned l_len;
317  *	};
318  */
319 static void encode_nlm_lock(struct xdr_stream *xdr,
320 			    const struct nlm_lock *lock)
321 {
322 	u32 l_offset, l_len;
323 	__be32 *p;
324 
325 	encode_caller_name(xdr, lock->caller);
326 	encode_fh(xdr, &lock->fh);
327 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
328 
329 	p = xdr_reserve_space(xdr, 4 + 4 + 4);
330 	*p++ = cpu_to_be32(lock->svid);
331 
332 	nlm_compute_offsets(lock, &l_offset, &l_len);
333 	*p++ = cpu_to_be32(l_offset);
334 	*p   = cpu_to_be32(l_len);
335 }
336 
337 
338 /*
339  * NLMv3 XDR encode functions
340  *
341  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
342  * "Protocols for Interworking: XNFS, Version 3W".
343  */
344 
345 /*
346  *	struct nlm_testargs {
347  *		netobj cookie;
348  *		bool exclusive;
349  *		struct nlm_lock alock;
350  *	};
351  */
352 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
353 				 struct xdr_stream *xdr,
354 				 const void *data)
355 {
356 	const struct nlm_args *args = data;
357 	const struct nlm_lock *lock = &args->lock;
358 
359 	encode_cookie(xdr, &args->cookie);
360 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
361 	encode_nlm_lock(xdr, lock);
362 }
363 
364 /*
365  *	struct nlm_lockargs {
366  *		netobj cookie;
367  *		bool block;
368  *		bool exclusive;
369  *		struct nlm_lock alock;
370  *		bool reclaim;
371  *		int state;
372  *	};
373  */
374 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
375 				 struct xdr_stream *xdr,
376 				 const void *data)
377 {
378 	const struct nlm_args *args = data;
379 	const struct nlm_lock *lock = &args->lock;
380 
381 	encode_cookie(xdr, &args->cookie);
382 	encode_bool(xdr, args->block);
383 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
384 	encode_nlm_lock(xdr, lock);
385 	encode_bool(xdr, args->reclaim);
386 	encode_int32(xdr, args->state);
387 }
388 
389 /*
390  *	struct nlm_cancargs {
391  *		netobj cookie;
392  *		bool block;
393  *		bool exclusive;
394  *		struct nlm_lock alock;
395  *	};
396  */
397 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
398 				 struct xdr_stream *xdr,
399 				 const void *data)
400 {
401 	const struct nlm_args *args = data;
402 	const struct nlm_lock *lock = &args->lock;
403 
404 	encode_cookie(xdr, &args->cookie);
405 	encode_bool(xdr, args->block);
406 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
407 	encode_nlm_lock(xdr, lock);
408 }
409 
410 /*
411  *	struct nlm_unlockargs {
412  *		netobj cookie;
413  *		struct nlm_lock alock;
414  *	};
415  */
416 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
417 				   struct xdr_stream *xdr,
418 				   const void *data)
419 {
420 	const struct nlm_args *args = data;
421 	const struct nlm_lock *lock = &args->lock;
422 
423 	encode_cookie(xdr, &args->cookie);
424 	encode_nlm_lock(xdr, lock);
425 }
426 
427 /*
428  *	struct nlm_res {
429  *		netobj cookie;
430  *		nlm_stat stat;
431  *	};
432  */
433 static void nlm_xdr_enc_res(struct rpc_rqst *req,
434 			    struct xdr_stream *xdr,
435 			    const void *data)
436 {
437 	const struct nlm_res *result = data;
438 
439 	encode_cookie(xdr, &result->cookie);
440 	encode_nlm_stat(xdr, result->status);
441 }
442 
443 /*
444  *	union nlm_testrply switch (nlm_stats stat) {
445  *	case LCK_DENIED:
446  *		struct nlm_holder holder;
447  *	default:
448  *		void;
449  *	};
450  *
451  *	struct nlm_testres {
452  *		netobj cookie;
453  *		nlm_testrply test_stat;
454  *	};
455  */
456 static void encode_nlm_testrply(struct xdr_stream *xdr,
457 				const struct nlm_res *result)
458 {
459 	if (result->status == nlm_lck_denied)
460 		encode_nlm_holder(xdr, result);
461 }
462 
463 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
464 				struct xdr_stream *xdr,
465 				const void *data)
466 {
467 	const struct nlm_res *result = data;
468 
469 	encode_cookie(xdr, &result->cookie);
470 	encode_nlm_stat(xdr, result->status);
471 	encode_nlm_testrply(xdr, result);
472 }
473 
474 
475 /*
476  * NLMv3 XDR decode functions
477  *
478  * NLMv3 result types are defined in Chapter 10 of The Open Group's
479  * "Protocols for Interworking: XNFS, Version 3W".
480  */
481 
482 /*
483  *	union nlm_testrply switch (nlm_stats stat) {
484  *	case LCK_DENIED:
485  *		struct nlm_holder holder;
486  *	default:
487  *		void;
488  *	};
489  *
490  *	struct nlm_testres {
491  *		netobj cookie;
492  *		nlm_testrply test_stat;
493  *	};
494  */
495 static int decode_nlm_testrply(struct xdr_stream *xdr,
496 			       struct nlm_res *result)
497 {
498 	int error;
499 
500 	error = decode_nlm_stat(xdr, &result->status);
501 	if (unlikely(error))
502 		goto out;
503 	if (result->status == nlm_lck_denied)
504 		error = decode_nlm_holder(xdr, result);
505 out:
506 	return error;
507 }
508 
509 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
510 			       struct xdr_stream *xdr,
511 			       void *data)
512 {
513 	struct nlm_res *result = data;
514 	int error;
515 
516 	error = decode_cookie(xdr, &result->cookie);
517 	if (unlikely(error))
518 		goto out;
519 	error = decode_nlm_testrply(xdr, result);
520 out:
521 	return error;
522 }
523 
524 /*
525  *	struct nlm_res {
526  *		netobj cookie;
527  *		nlm_stat stat;
528  *	};
529  */
530 static int nlm_xdr_dec_res(struct rpc_rqst *req,
531 			   struct xdr_stream *xdr,
532 			   void *data)
533 {
534 	struct nlm_res *result = data;
535 	int error;
536 
537 	error = decode_cookie(xdr, &result->cookie);
538 	if (unlikely(error))
539 		goto out;
540 	error = decode_nlm_stat(xdr, &result->status);
541 out:
542 	return error;
543 }
544 
545 
546 /*
547  * For NLM, a void procedure really returns nothing
548  */
549 #define nlm_xdr_dec_norep	NULL
550 
551 #define PROC(proc, argtype, restype)	\
552 [NLMPROC_##proc] = {							\
553 	.p_proc      = NLMPROC_##proc,					\
554 	.p_encode    = nlm_xdr_enc_##argtype,		\
555 	.p_decode    = nlm_xdr_dec_##restype,				\
556 	.p_arglen    = NLM_##argtype##_sz,				\
557 	.p_replen    = NLM_##restype##_sz,				\
558 	.p_statidx   = NLMPROC_##proc,					\
559 	.p_name      = #proc,						\
560 	}
561 
562 static const struct rpc_procinfo nlm_procedures[] = {
563 	PROC(TEST,		testargs,	testres),
564 	PROC(LOCK,		lockargs,	res),
565 	PROC(CANCEL,		cancargs,	res),
566 	PROC(UNLOCK,		unlockargs,	res),
567 	PROC(GRANTED,		testargs,	res),
568 	PROC(TEST_MSG,		testargs,	norep),
569 	PROC(LOCK_MSG,		lockargs,	norep),
570 	PROC(CANCEL_MSG,	cancargs,	norep),
571 	PROC(UNLOCK_MSG,	unlockargs,	norep),
572 	PROC(GRANTED_MSG,	testargs,	norep),
573 	PROC(TEST_RES,		testres,	norep),
574 	PROC(LOCK_RES,		res,		norep),
575 	PROC(CANCEL_RES,	res,		norep),
576 	PROC(UNLOCK_RES,	res,		norep),
577 	PROC(GRANTED_RES,	res,		norep),
578 };
579 
580 static unsigned int nlm_version1_counts[ARRAY_SIZE(nlm_procedures)];
581 static const struct rpc_version	nlm_version1 = {
582 	.number		= 1,
583 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
584 	.procs		= nlm_procedures,
585 	.counts		= nlm_version1_counts,
586 };
587 
588 static unsigned int nlm_version3_counts[ARRAY_SIZE(nlm_procedures)];
589 static const struct rpc_version	nlm_version3 = {
590 	.number		= 3,
591 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
592 	.procs		= nlm_procedures,
593 	.counts		= nlm_version3_counts,
594 };
595 
596 static const struct rpc_version	*nlm_versions[] = {
597 	[1] = &nlm_version1,
598 	[3] = &nlm_version3,
599 #ifdef CONFIG_LOCKD_V4
600 	[4] = &nlm_version4,
601 #endif
602 };
603 
604 static struct rpc_stat		nlm_rpc_stats;
605 
606 const struct rpc_program	nlm_program = {
607 	.name		= "lockd",
608 	.number		= NLM_PROGRAM,
609 	.nrvers		= ARRAY_SIZE(nlm_versions),
610 	.version	= nlm_versions,
611 	.stats		= &nlm_rpc_stats,
612 };
613