xref: /openbmc/linux/fs/lockd/clntxdr.c (revision d5dbb2e8) 
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  * Handle decode buffer overflows out-of-line.
75  */
76 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
77 {
78 	dprintk("lockd: %s prematurely hit the end of our receive buffer. "
79 		"Remaining buffer length is %tu words.\n",
80 		func, xdr->end - xdr->p);
81 }
82 
83 
84 /*
85  * Encode/decode NLMv3 basic data types
86  *
87  * Basic NLMv3 data types are not defined in an IETF standards
88  * document.  X/Open has a description of these data types that
89  * is useful.  See Chapter 10 of "Protocols for Interworking:
90  * XNFS, Version 3W".
91  *
92  * Not all basic data types have their own encoding and decoding
93  * functions.  For run-time efficiency, some data types are encoded
94  * or decoded inline.
95  */
96 
97 static void encode_bool(struct xdr_stream *xdr, const int value)
98 {
99 	__be32 *p;
100 
101 	p = xdr_reserve_space(xdr, 4);
102 	*p = value ? xdr_one : xdr_zero;
103 }
104 
105 static void encode_int32(struct xdr_stream *xdr, const s32 value)
106 {
107 	__be32 *p;
108 
109 	p = xdr_reserve_space(xdr, 4);
110 	*p = cpu_to_be32(value);
111 }
112 
113 /*
114  *	typedef opaque netobj<MAXNETOBJ_SZ>
115  */
116 static void encode_netobj(struct xdr_stream *xdr,
117 			  const u8 *data, const unsigned int length)
118 {
119 	__be32 *p;
120 
121 	p = xdr_reserve_space(xdr, 4 + length);
122 	xdr_encode_opaque(p, data, length);
123 }
124 
125 static int decode_netobj(struct xdr_stream *xdr,
126 			 struct xdr_netobj *obj)
127 {
128 	ssize_t ret;
129 
130 	ret = xdr_stream_decode_opaque_inline(xdr, (void *)&obj->data,
131 			XDR_MAX_NETOBJ);
132 	if (unlikely(ret < 0))
133 		return -EIO;
134 	obj->len = ret;
135 	return 0;
136 }
137 
138 /*
139  *	netobj cookie;
140  */
141 static void encode_cookie(struct xdr_stream *xdr,
142 			  const struct nlm_cookie *cookie)
143 {
144 	encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
145 }
146 
147 static int decode_cookie(struct xdr_stream *xdr,
148 			 struct nlm_cookie *cookie)
149 {
150 	u32 length;
151 	__be32 *p;
152 
153 	p = xdr_inline_decode(xdr, 4);
154 	if (unlikely(p == NULL))
155 		goto out_overflow;
156 	length = be32_to_cpup(p++);
157 	/* apparently HPUX can return empty cookies */
158 	if (length == 0)
159 		goto out_hpux;
160 	if (length > NLM_MAXCOOKIELEN)
161 		goto out_size;
162 	p = xdr_inline_decode(xdr, length);
163 	if (unlikely(p == NULL))
164 		goto out_overflow;
165 	cookie->len = length;
166 	memcpy(cookie->data, p, length);
167 	return 0;
168 out_hpux:
169 	cookie->len = 4;
170 	memset(cookie->data, 0, 4);
171 	return 0;
172 out_size:
173 	dprintk("NFS: returned cookie was too long: %u\n", length);
174 	return -EIO;
175 out_overflow:
176 	print_overflow_msg(__func__, xdr);
177 	return -EIO;
178 }
179 
180 /*
181  *	netobj fh;
182  */
183 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
184 {
185 	encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
186 }
187 
188 /*
189  *	enum nlm_stats {
190  *		LCK_GRANTED = 0,
191  *		LCK_DENIED = 1,
192  *		LCK_DENIED_NOLOCKS = 2,
193  *		LCK_BLOCKED = 3,
194  *		LCK_DENIED_GRACE_PERIOD = 4
195  *	};
196  *
197  *
198  *	struct nlm_stat {
199  *		nlm_stats stat;
200  *	};
201  *
202  * NB: we don't swap bytes for the NLM status values.  The upper
203  * layers deal directly with the status value in network byte
204  * order.
205  */
206 
207 static void encode_nlm_stat(struct xdr_stream *xdr,
208 			    const __be32 stat)
209 {
210 	__be32 *p;
211 
212 	WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
213 	p = xdr_reserve_space(xdr, 4);
214 	*p = stat;
215 }
216 
217 static int decode_nlm_stat(struct xdr_stream *xdr,
218 			   __be32 *stat)
219 {
220 	__be32 *p;
221 
222 	p = xdr_inline_decode(xdr, 4);
223 	if (unlikely(p == NULL))
224 		goto out_overflow;
225 	if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
226 		goto out_enum;
227 	*stat = *p;
228 	return 0;
229 out_enum:
230 	dprintk("%s: server returned invalid nlm_stats value: %u\n",
231 		__func__, be32_to_cpup(p));
232 	return -EIO;
233 out_overflow:
234 	print_overflow_msg(__func__, xdr);
235 	return -EIO;
236 }
237 
238 /*
239  *	struct nlm_holder {
240  *		bool exclusive;
241  *		int uppid;
242  *		netobj oh;
243  *		unsigned l_offset;
244  *		unsigned l_len;
245  *	};
246  */
247 static void encode_nlm_holder(struct xdr_stream *xdr,
248 			      const struct nlm_res *result)
249 {
250 	const struct nlm_lock *lock = &result->lock;
251 	u32 l_offset, l_len;
252 	__be32 *p;
253 
254 	encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
255 	encode_int32(xdr, lock->svid);
256 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
257 
258 	p = xdr_reserve_space(xdr, 4 + 4);
259 	nlm_compute_offsets(lock, &l_offset, &l_len);
260 	*p++ = cpu_to_be32(l_offset);
261 	*p   = cpu_to_be32(l_len);
262 }
263 
264 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
265 {
266 	struct nlm_lock *lock = &result->lock;
267 	struct file_lock *fl = &lock->fl;
268 	u32 exclusive, l_offset, l_len;
269 	int error;
270 	__be32 *p;
271 	s32 end;
272 
273 	memset(lock, 0, sizeof(*lock));
274 	locks_init_lock(fl);
275 
276 	p = xdr_inline_decode(xdr, 4 + 4);
277 	if (unlikely(p == NULL))
278 		goto out_overflow;
279 	exclusive = be32_to_cpup(p++);
280 	lock->svid = be32_to_cpup(p);
281 	fl->fl_pid = (pid_t)lock->svid;
282 
283 	error = decode_netobj(xdr, &lock->oh);
284 	if (unlikely(error))
285 		goto out;
286 
287 	p = xdr_inline_decode(xdr, 4 + 4);
288 	if (unlikely(p == NULL))
289 		goto out_overflow;
290 
291 	fl->fl_flags = FL_POSIX;
292 	fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
293 	l_offset = be32_to_cpup(p++);
294 	l_len = be32_to_cpup(p);
295 	end = l_offset + l_len - 1;
296 
297 	fl->fl_start = (loff_t)l_offset;
298 	if (l_len == 0 || end < 0)
299 		fl->fl_end = OFFSET_MAX;
300 	else
301 		fl->fl_end = (loff_t)end;
302 	error = 0;
303 out:
304 	return error;
305 out_overflow:
306 	print_overflow_msg(__func__, xdr);
307 	return -EIO;
308 }
309 
310 /*
311  *	string caller_name<LM_MAXSTRLEN>;
312  */
313 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
314 {
315 	/* NB: client-side does not set lock->len */
316 	u32 length = strlen(name);
317 	__be32 *p;
318 
319 	p = xdr_reserve_space(xdr, 4 + length);
320 	xdr_encode_opaque(p, name, length);
321 }
322 
323 /*
324  *	struct nlm_lock {
325  *		string caller_name<LM_MAXSTRLEN>;
326  *		netobj fh;
327  *		netobj oh;
328  *		int uppid;
329  *		unsigned l_offset;
330  *		unsigned l_len;
331  *	};
332  */
333 static void encode_nlm_lock(struct xdr_stream *xdr,
334 			    const struct nlm_lock *lock)
335 {
336 	u32 l_offset, l_len;
337 	__be32 *p;
338 
339 	encode_caller_name(xdr, lock->caller);
340 	encode_fh(xdr, &lock->fh);
341 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
342 
343 	p = xdr_reserve_space(xdr, 4 + 4 + 4);
344 	*p++ = cpu_to_be32(lock->svid);
345 
346 	nlm_compute_offsets(lock, &l_offset, &l_len);
347 	*p++ = cpu_to_be32(l_offset);
348 	*p   = cpu_to_be32(l_len);
349 }
350 
351 
352 /*
353  * NLMv3 XDR encode functions
354  *
355  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
356  * "Protocols for Interworking: XNFS, Version 3W".
357  */
358 
359 /*
360  *	struct nlm_testargs {
361  *		netobj cookie;
362  *		bool exclusive;
363  *		struct nlm_lock alock;
364  *	};
365  */
366 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
367 				 struct xdr_stream *xdr,
368 				 const void *data)
369 {
370 	const struct nlm_args *args = data;
371 	const struct nlm_lock *lock = &args->lock;
372 
373 	encode_cookie(xdr, &args->cookie);
374 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
375 	encode_nlm_lock(xdr, lock);
376 }
377 
378 /*
379  *	struct nlm_lockargs {
380  *		netobj cookie;
381  *		bool block;
382  *		bool exclusive;
383  *		struct nlm_lock alock;
384  *		bool reclaim;
385  *		int state;
386  *	};
387  */
388 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
389 				 struct xdr_stream *xdr,
390 				 const void *data)
391 {
392 	const struct nlm_args *args = data;
393 	const struct nlm_lock *lock = &args->lock;
394 
395 	encode_cookie(xdr, &args->cookie);
396 	encode_bool(xdr, args->block);
397 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
398 	encode_nlm_lock(xdr, lock);
399 	encode_bool(xdr, args->reclaim);
400 	encode_int32(xdr, args->state);
401 }
402 
403 /*
404  *	struct nlm_cancargs {
405  *		netobj cookie;
406  *		bool block;
407  *		bool exclusive;
408  *		struct nlm_lock alock;
409  *	};
410  */
411 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
412 				 struct xdr_stream *xdr,
413 				 const void *data)
414 {
415 	const struct nlm_args *args = data;
416 	const struct nlm_lock *lock = &args->lock;
417 
418 	encode_cookie(xdr, &args->cookie);
419 	encode_bool(xdr, args->block);
420 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
421 	encode_nlm_lock(xdr, lock);
422 }
423 
424 /*
425  *	struct nlm_unlockargs {
426  *		netobj cookie;
427  *		struct nlm_lock alock;
428  *	};
429  */
430 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
431 				   struct xdr_stream *xdr,
432 				   const void *data)
433 {
434 	const struct nlm_args *args = data;
435 	const struct nlm_lock *lock = &args->lock;
436 
437 	encode_cookie(xdr, &args->cookie);
438 	encode_nlm_lock(xdr, lock);
439 }
440 
441 /*
442  *	struct nlm_res {
443  *		netobj cookie;
444  *		nlm_stat stat;
445  *	};
446  */
447 static void nlm_xdr_enc_res(struct rpc_rqst *req,
448 			    struct xdr_stream *xdr,
449 			    const void *data)
450 {
451 	const struct nlm_res *result = data;
452 
453 	encode_cookie(xdr, &result->cookie);
454 	encode_nlm_stat(xdr, result->status);
455 }
456 
457 /*
458  *	union nlm_testrply switch (nlm_stats stat) {
459  *	case LCK_DENIED:
460  *		struct nlm_holder holder;
461  *	default:
462  *		void;
463  *	};
464  *
465  *	struct nlm_testres {
466  *		netobj cookie;
467  *		nlm_testrply test_stat;
468  *	};
469  */
470 static void encode_nlm_testrply(struct xdr_stream *xdr,
471 				const struct nlm_res *result)
472 {
473 	if (result->status == nlm_lck_denied)
474 		encode_nlm_holder(xdr, result);
475 }
476 
477 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
478 				struct xdr_stream *xdr,
479 				const void *data)
480 {
481 	const struct nlm_res *result = data;
482 
483 	encode_cookie(xdr, &result->cookie);
484 	encode_nlm_stat(xdr, result->status);
485 	encode_nlm_testrply(xdr, result);
486 }
487 
488 
489 /*
490  * NLMv3 XDR decode functions
491  *
492  * NLMv3 result types are defined in Chapter 10 of The Open Group's
493  * "Protocols for Interworking: XNFS, Version 3W".
494  */
495 
496 /*
497  *	union nlm_testrply switch (nlm_stats stat) {
498  *	case LCK_DENIED:
499  *		struct nlm_holder holder;
500  *	default:
501  *		void;
502  *	};
503  *
504  *	struct nlm_testres {
505  *		netobj cookie;
506  *		nlm_testrply test_stat;
507  *	};
508  */
509 static int decode_nlm_testrply(struct xdr_stream *xdr,
510 			       struct nlm_res *result)
511 {
512 	int error;
513 
514 	error = decode_nlm_stat(xdr, &result->status);
515 	if (unlikely(error))
516 		goto out;
517 	if (result->status == nlm_lck_denied)
518 		error = decode_nlm_holder(xdr, result);
519 out:
520 	return error;
521 }
522 
523 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
524 			       struct xdr_stream *xdr,
525 			       void *data)
526 {
527 	struct nlm_res *result = data;
528 	int error;
529 
530 	error = decode_cookie(xdr, &result->cookie);
531 	if (unlikely(error))
532 		goto out;
533 	error = decode_nlm_testrply(xdr, result);
534 out:
535 	return error;
536 }
537 
538 /*
539  *	struct nlm_res {
540  *		netobj cookie;
541  *		nlm_stat stat;
542  *	};
543  */
544 static int nlm_xdr_dec_res(struct rpc_rqst *req,
545 			   struct xdr_stream *xdr,
546 			   void *data)
547 {
548 	struct nlm_res *result = data;
549 	int error;
550 
551 	error = decode_cookie(xdr, &result->cookie);
552 	if (unlikely(error))
553 		goto out;
554 	error = decode_nlm_stat(xdr, &result->status);
555 out:
556 	return error;
557 }
558 
559 
560 /*
561  * For NLM, a void procedure really returns nothing
562  */
563 #define nlm_xdr_dec_norep	NULL
564 
565 #define PROC(proc, argtype, restype)	\
566 [NLMPROC_##proc] = {							\
567 	.p_proc      = NLMPROC_##proc,					\
568 	.p_encode    = nlm_xdr_enc_##argtype,		\
569 	.p_decode    = nlm_xdr_dec_##restype,				\
570 	.p_arglen    = NLM_##argtype##_sz,				\
571 	.p_replen    = NLM_##restype##_sz,				\
572 	.p_statidx   = NLMPROC_##proc,					\
573 	.p_name      = #proc,						\
574 	}
575 
576 static const struct rpc_procinfo nlm_procedures[] = {
577 	PROC(TEST,		testargs,	testres),
578 	PROC(LOCK,		lockargs,	res),
579 	PROC(CANCEL,		cancargs,	res),
580 	PROC(UNLOCK,		unlockargs,	res),
581 	PROC(GRANTED,		testargs,	res),
582 	PROC(TEST_MSG,		testargs,	norep),
583 	PROC(LOCK_MSG,		lockargs,	norep),
584 	PROC(CANCEL_MSG,	cancargs,	norep),
585 	PROC(UNLOCK_MSG,	unlockargs,	norep),
586 	PROC(GRANTED_MSG,	testargs,	norep),
587 	PROC(TEST_RES,		testres,	norep),
588 	PROC(LOCK_RES,		res,		norep),
589 	PROC(CANCEL_RES,	res,		norep),
590 	PROC(UNLOCK_RES,	res,		norep),
591 	PROC(GRANTED_RES,	res,		norep),
592 };
593 
594 static unsigned int nlm_version1_counts[ARRAY_SIZE(nlm_procedures)];
595 static const struct rpc_version	nlm_version1 = {
596 	.number		= 1,
597 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
598 	.procs		= nlm_procedures,
599 	.counts		= nlm_version1_counts,
600 };
601 
602 static unsigned int nlm_version3_counts[ARRAY_SIZE(nlm_procedures)];
603 static const struct rpc_version	nlm_version3 = {
604 	.number		= 3,
605 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
606 	.procs		= nlm_procedures,
607 	.counts		= nlm_version3_counts,
608 };
609 
610 static const struct rpc_version	*nlm_versions[] = {
611 	[1] = &nlm_version1,
612 	[3] = &nlm_version3,
613 #ifdef CONFIG_LOCKD_V4
614 	[4] = &nlm_version4,
615 #endif
616 };
617 
618 static struct rpc_stat		nlm_rpc_stats;
619 
620 const struct rpc_program	nlm_program = {
621 	.name		= "lockd",
622 	.number		= NLM_PROGRAM,
623 	.nrvers		= ARRAY_SIZE(nlm_versions),
624 	.version	= nlm_versions,
625 	.stats		= &nlm_rpc_stats,
626 };
627