xref: /openbmc/linux/fs/lockd/clntxdr.c (revision 4da722ca19f30f7db250db808d1ab1703607a932) 
1 /*
2  * linux/fs/lockd/clntxdr.c
3  *
4  * XDR functions to encode/decode NLM version 3 RPC arguments and results.
5  * NLM version 3 is backwards compatible with NLM versions 1 and 2.
6  *
7  * NLM client-side only.
8  *
9  * Copyright (C) 2010, Oracle.  All rights reserved.
10  */
11 
12 #include <linux/types.h>
13 #include <linux/sunrpc/xdr.h>
14 #include <linux/sunrpc/clnt.h>
15 #include <linux/sunrpc/stats.h>
16 #include <linux/lockd/lockd.h>
17 
18 #include <uapi/linux/nfs2.h>
19 
20 #define NLMDBG_FACILITY		NLMDBG_XDR
21 
22 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
23 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
24 #endif
25 
26 /*
27  * Declare the space requirements for NLM arguments and replies as
28  * number of 32bit-words
29  */
30 #define NLM_cookie_sz		(1+(NLM_MAXCOOKIELEN>>2))
31 #define NLM_caller_sz		(1+(NLMCLNT_OHSIZE>>2))
32 #define NLM_owner_sz		(1+(NLMCLNT_OHSIZE>>2))
33 #define NLM_fhandle_sz		(1+(NFS2_FHSIZE>>2))
34 #define NLM_lock_sz		(3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
35 #define NLM_holder_sz		(4+NLM_owner_sz)
36 
37 #define NLM_testargs_sz		(NLM_cookie_sz+1+NLM_lock_sz)
38 #define NLM_lockargs_sz		(NLM_cookie_sz+4+NLM_lock_sz)
39 #define NLM_cancargs_sz		(NLM_cookie_sz+2+NLM_lock_sz)
40 #define NLM_unlockargs_sz	(NLM_cookie_sz+NLM_lock_sz)
41 
42 #define NLM_testres_sz		(NLM_cookie_sz+1+NLM_holder_sz)
43 #define NLM_res_sz		(NLM_cookie_sz+1)
44 #define NLM_norep_sz		(0)
45 
46 
47 static s32 loff_t_to_s32(loff_t offset)
48 {
49 	s32 res;
50 
51 	if (offset >= NLM_OFFSET_MAX)
52 		res = NLM_OFFSET_MAX;
53 	else if (offset <= -NLM_OFFSET_MAX)
54 		res = -NLM_OFFSET_MAX;
55 	else
56 		res = offset;
57 	return res;
58 }
59 
60 static void nlm_compute_offsets(const struct nlm_lock *lock,
61 				u32 *l_offset, u32 *l_len)
62 {
63 	const struct file_lock *fl = &lock->fl;
64 
65 	*l_offset = loff_t_to_s32(fl->fl_start);
66 	if (fl->fl_end == OFFSET_MAX)
67 		*l_len = 0;
68 	else
69 		*l_len = loff_t_to_s32(fl->fl_end - fl->fl_start + 1);
70 }
71 
72 /*
73  * Handle decode buffer overflows out-of-line.
74  */
75 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
76 {
77 	dprintk("lockd: %s prematurely hit the end of our receive buffer. "
78 		"Remaining buffer length is %tu words.\n",
79 		func, xdr->end - xdr->p);
80 }
81 
82 
83 /*
84  * Encode/decode NLMv3 basic data types
85  *
86  * Basic NLMv3 data types are not defined in an IETF standards
87  * document.  X/Open has a description of these data types that
88  * is useful.  See Chapter 10 of "Protocols for Interworking:
89  * XNFS, Version 3W".
90  *
91  * Not all basic data types have their own encoding and decoding
92  * functions.  For run-time efficiency, some data types are encoded
93  * or decoded inline.
94  */
95 
96 static void encode_bool(struct xdr_stream *xdr, const int value)
97 {
98 	__be32 *p;
99 
100 	p = xdr_reserve_space(xdr, 4);
101 	*p = value ? xdr_one : xdr_zero;
102 }
103 
104 static void encode_int32(struct xdr_stream *xdr, const s32 value)
105 {
106 	__be32 *p;
107 
108 	p = xdr_reserve_space(xdr, 4);
109 	*p = cpu_to_be32(value);
110 }
111 
112 /*
113  *	typedef opaque netobj<MAXNETOBJ_SZ>
114  */
115 static void encode_netobj(struct xdr_stream *xdr,
116 			  const u8 *data, const unsigned int length)
117 {
118 	__be32 *p;
119 
120 	p = xdr_reserve_space(xdr, 4 + length);
121 	xdr_encode_opaque(p, data, length);
122 }
123 
124 static int decode_netobj(struct xdr_stream *xdr,
125 			 struct xdr_netobj *obj)
126 {
127 	u32 length;
128 	__be32 *p;
129 
130 	p = xdr_inline_decode(xdr, 4);
131 	if (unlikely(p == NULL))
132 		goto out_overflow;
133 	length = be32_to_cpup(p++);
134 	if (unlikely(length > XDR_MAX_NETOBJ))
135 		goto out_size;
136 	obj->len = length;
137 	obj->data = (u8 *)p;
138 	return 0;
139 out_size:
140 	dprintk("NFS: returned netobj was too long: %u\n", length);
141 	return -EIO;
142 out_overflow:
143 	print_overflow_msg(__func__, xdr);
144 	return -EIO;
145 }
146 
147 /*
148  *	netobj cookie;
149  */
150 static void encode_cookie(struct xdr_stream *xdr,
151 			  const struct nlm_cookie *cookie)
152 {
153 	encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
154 }
155 
156 static int decode_cookie(struct xdr_stream *xdr,
157 			 struct nlm_cookie *cookie)
158 {
159 	u32 length;
160 	__be32 *p;
161 
162 	p = xdr_inline_decode(xdr, 4);
163 	if (unlikely(p == NULL))
164 		goto out_overflow;
165 	length = be32_to_cpup(p++);
166 	/* apparently HPUX can return empty cookies */
167 	if (length == 0)
168 		goto out_hpux;
169 	if (length > NLM_MAXCOOKIELEN)
170 		goto out_size;
171 	p = xdr_inline_decode(xdr, length);
172 	if (unlikely(p == NULL))
173 		goto out_overflow;
174 	cookie->len = length;
175 	memcpy(cookie->data, p, length);
176 	return 0;
177 out_hpux:
178 	cookie->len = 4;
179 	memset(cookie->data, 0, 4);
180 	return 0;
181 out_size:
182 	dprintk("NFS: returned cookie was too long: %u\n", length);
183 	return -EIO;
184 out_overflow:
185 	print_overflow_msg(__func__, xdr);
186 	return -EIO;
187 }
188 
189 /*
190  *	netobj fh;
191  */
192 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
193 {
194 	encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
195 }
196 
197 /*
198  *	enum nlm_stats {
199  *		LCK_GRANTED = 0,
200  *		LCK_DENIED = 1,
201  *		LCK_DENIED_NOLOCKS = 2,
202  *		LCK_BLOCKED = 3,
203  *		LCK_DENIED_GRACE_PERIOD = 4
204  *	};
205  *
206  *
207  *	struct nlm_stat {
208  *		nlm_stats stat;
209  *	};
210  *
211  * NB: we don't swap bytes for the NLM status values.  The upper
212  * layers deal directly with the status value in network byte
213  * order.
214  */
215 
216 static void encode_nlm_stat(struct xdr_stream *xdr,
217 			    const __be32 stat)
218 {
219 	__be32 *p;
220 
221 	WARN_ON_ONCE(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
222 	p = xdr_reserve_space(xdr, 4);
223 	*p = stat;
224 }
225 
226 static int decode_nlm_stat(struct xdr_stream *xdr,
227 			   __be32 *stat)
228 {
229 	__be32 *p;
230 
231 	p = xdr_inline_decode(xdr, 4);
232 	if (unlikely(p == NULL))
233 		goto out_overflow;
234 	if (unlikely(ntohl(*p) > ntohl(nlm_lck_denied_grace_period)))
235 		goto out_enum;
236 	*stat = *p;
237 	return 0;
238 out_enum:
239 	dprintk("%s: server returned invalid nlm_stats value: %u\n",
240 		__func__, be32_to_cpup(p));
241 	return -EIO;
242 out_overflow:
243 	print_overflow_msg(__func__, xdr);
244 	return -EIO;
245 }
246 
247 /*
248  *	struct nlm_holder {
249  *		bool exclusive;
250  *		int uppid;
251  *		netobj oh;
252  *		unsigned l_offset;
253  *		unsigned l_len;
254  *	};
255  */
256 static void encode_nlm_holder(struct xdr_stream *xdr,
257 			      const struct nlm_res *result)
258 {
259 	const struct nlm_lock *lock = &result->lock;
260 	u32 l_offset, l_len;
261 	__be32 *p;
262 
263 	encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
264 	encode_int32(xdr, lock->svid);
265 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
266 
267 	p = xdr_reserve_space(xdr, 4 + 4);
268 	nlm_compute_offsets(lock, &l_offset, &l_len);
269 	*p++ = cpu_to_be32(l_offset);
270 	*p   = cpu_to_be32(l_len);
271 }
272 
273 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
274 {
275 	struct nlm_lock *lock = &result->lock;
276 	struct file_lock *fl = &lock->fl;
277 	u32 exclusive, l_offset, l_len;
278 	int error;
279 	__be32 *p;
280 	s32 end;
281 
282 	memset(lock, 0, sizeof(*lock));
283 	locks_init_lock(fl);
284 
285 	p = xdr_inline_decode(xdr, 4 + 4);
286 	if (unlikely(p == NULL))
287 		goto out_overflow;
288 	exclusive = be32_to_cpup(p++);
289 	lock->svid = be32_to_cpup(p);
290 	fl->fl_pid = (pid_t)lock->svid;
291 
292 	error = decode_netobj(xdr, &lock->oh);
293 	if (unlikely(error))
294 		goto out;
295 
296 	p = xdr_inline_decode(xdr, 4 + 4);
297 	if (unlikely(p == NULL))
298 		goto out_overflow;
299 
300 	fl->fl_flags = FL_POSIX;
301 	fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
302 	l_offset = be32_to_cpup(p++);
303 	l_len = be32_to_cpup(p);
304 	end = l_offset + l_len - 1;
305 
306 	fl->fl_start = (loff_t)l_offset;
307 	if (l_len == 0 || end < 0)
308 		fl->fl_end = OFFSET_MAX;
309 	else
310 		fl->fl_end = (loff_t)end;
311 	error = 0;
312 out:
313 	return error;
314 out_overflow:
315 	print_overflow_msg(__func__, xdr);
316 	return -EIO;
317 }
318 
319 /*
320  *	string caller_name<LM_MAXSTRLEN>;
321  */
322 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
323 {
324 	/* NB: client-side does not set lock->len */
325 	u32 length = strlen(name);
326 	__be32 *p;
327 
328 	p = xdr_reserve_space(xdr, 4 + length);
329 	xdr_encode_opaque(p, name, length);
330 }
331 
332 /*
333  *	struct nlm_lock {
334  *		string caller_name<LM_MAXSTRLEN>;
335  *		netobj fh;
336  *		netobj oh;
337  *		int uppid;
338  *		unsigned l_offset;
339  *		unsigned l_len;
340  *	};
341  */
342 static void encode_nlm_lock(struct xdr_stream *xdr,
343 			    const struct nlm_lock *lock)
344 {
345 	u32 l_offset, l_len;
346 	__be32 *p;
347 
348 	encode_caller_name(xdr, lock->caller);
349 	encode_fh(xdr, &lock->fh);
350 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
351 
352 	p = xdr_reserve_space(xdr, 4 + 4 + 4);
353 	*p++ = cpu_to_be32(lock->svid);
354 
355 	nlm_compute_offsets(lock, &l_offset, &l_len);
356 	*p++ = cpu_to_be32(l_offset);
357 	*p   = cpu_to_be32(l_len);
358 }
359 
360 
361 /*
362  * NLMv3 XDR encode functions
363  *
364  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
365  * "Protocols for Interworking: XNFS, Version 3W".
366  */
367 
368 /*
369  *	struct nlm_testargs {
370  *		netobj cookie;
371  *		bool exclusive;
372  *		struct nlm_lock alock;
373  *	};
374  */
375 static void nlm_xdr_enc_testargs(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, lock->fl.fl_type == F_WRLCK);
384 	encode_nlm_lock(xdr, lock);
385 }
386 
387 /*
388  *	struct nlm_lockargs {
389  *		netobj cookie;
390  *		bool block;
391  *		bool exclusive;
392  *		struct nlm_lock alock;
393  *		bool reclaim;
394  *		int state;
395  *	};
396  */
397 static void nlm_xdr_enc_lockargs(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 	encode_bool(xdr, args->reclaim);
409 	encode_int32(xdr, args->state);
410 }
411 
412 /*
413  *	struct nlm_cancargs {
414  *		netobj cookie;
415  *		bool block;
416  *		bool exclusive;
417  *		struct nlm_lock alock;
418  *	};
419  */
420 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
421 				 struct xdr_stream *xdr,
422 				 const void *data)
423 {
424 	const struct nlm_args *args = data;
425 	const struct nlm_lock *lock = &args->lock;
426 
427 	encode_cookie(xdr, &args->cookie);
428 	encode_bool(xdr, args->block);
429 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
430 	encode_nlm_lock(xdr, lock);
431 }
432 
433 /*
434  *	struct nlm_unlockargs {
435  *		netobj cookie;
436  *		struct nlm_lock alock;
437  *	};
438  */
439 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
440 				   struct xdr_stream *xdr,
441 				   const void *data)
442 {
443 	const struct nlm_args *args = data;
444 	const struct nlm_lock *lock = &args->lock;
445 
446 	encode_cookie(xdr, &args->cookie);
447 	encode_nlm_lock(xdr, lock);
448 }
449 
450 /*
451  *	struct nlm_res {
452  *		netobj cookie;
453  *		nlm_stat stat;
454  *	};
455  */
456 static void nlm_xdr_enc_res(struct rpc_rqst *req,
457 			    struct xdr_stream *xdr,
458 			    const void *data)
459 {
460 	const struct nlm_res *result = data;
461 
462 	encode_cookie(xdr, &result->cookie);
463 	encode_nlm_stat(xdr, result->status);
464 }
465 
466 /*
467  *	union nlm_testrply switch (nlm_stats stat) {
468  *	case LCK_DENIED:
469  *		struct nlm_holder holder;
470  *	default:
471  *		void;
472  *	};
473  *
474  *	struct nlm_testres {
475  *		netobj cookie;
476  *		nlm_testrply test_stat;
477  *	};
478  */
479 static void encode_nlm_testrply(struct xdr_stream *xdr,
480 				const struct nlm_res *result)
481 {
482 	if (result->status == nlm_lck_denied)
483 		encode_nlm_holder(xdr, result);
484 }
485 
486 static void nlm_xdr_enc_testres(struct rpc_rqst *req,
487 				struct xdr_stream *xdr,
488 				const void *data)
489 {
490 	const struct nlm_res *result = data;
491 
492 	encode_cookie(xdr, &result->cookie);
493 	encode_nlm_stat(xdr, result->status);
494 	encode_nlm_testrply(xdr, result);
495 }
496 
497 
498 /*
499  * NLMv3 XDR decode functions
500  *
501  * NLMv3 result types are defined in Chapter 10 of The Open Group's
502  * "Protocols for Interworking: XNFS, Version 3W".
503  */
504 
505 /*
506  *	union nlm_testrply switch (nlm_stats stat) {
507  *	case LCK_DENIED:
508  *		struct nlm_holder holder;
509  *	default:
510  *		void;
511  *	};
512  *
513  *	struct nlm_testres {
514  *		netobj cookie;
515  *		nlm_testrply test_stat;
516  *	};
517  */
518 static int decode_nlm_testrply(struct xdr_stream *xdr,
519 			       struct nlm_res *result)
520 {
521 	int error;
522 
523 	error = decode_nlm_stat(xdr, &result->status);
524 	if (unlikely(error))
525 		goto out;
526 	if (result->status == nlm_lck_denied)
527 		error = decode_nlm_holder(xdr, result);
528 out:
529 	return error;
530 }
531 
532 static int nlm_xdr_dec_testres(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_testrply(xdr, result);
543 out:
544 	return error;
545 }
546 
547 /*
548  *	struct nlm_res {
549  *		netobj cookie;
550  *		nlm_stat stat;
551  *	};
552  */
553 static int nlm_xdr_dec_res(struct rpc_rqst *req,
554 			   struct xdr_stream *xdr,
555 			   void *data)
556 {
557 	struct nlm_res *result = data;
558 	int error;
559 
560 	error = decode_cookie(xdr, &result->cookie);
561 	if (unlikely(error))
562 		goto out;
563 	error = decode_nlm_stat(xdr, &result->status);
564 out:
565 	return error;
566 }
567 
568 
569 /*
570  * For NLM, a void procedure really returns nothing
571  */
572 #define nlm_xdr_dec_norep	NULL
573 
574 #define PROC(proc, argtype, restype)	\
575 [NLMPROC_##proc] = {							\
576 	.p_proc      = NLMPROC_##proc,					\
577 	.p_encode    = nlm_xdr_enc_##argtype,		\
578 	.p_decode    = nlm_xdr_dec_##restype,				\
579 	.p_arglen    = NLM_##argtype##_sz,				\
580 	.p_replen    = NLM_##restype##_sz,				\
581 	.p_statidx   = NLMPROC_##proc,					\
582 	.p_name      = #proc,						\
583 	}
584 
585 static const struct rpc_procinfo nlm_procedures[] = {
586 	PROC(TEST,		testargs,	testres),
587 	PROC(LOCK,		lockargs,	res),
588 	PROC(CANCEL,		cancargs,	res),
589 	PROC(UNLOCK,		unlockargs,	res),
590 	PROC(GRANTED,		testargs,	res),
591 	PROC(TEST_MSG,		testargs,	norep),
592 	PROC(LOCK_MSG,		lockargs,	norep),
593 	PROC(CANCEL_MSG,	cancargs,	norep),
594 	PROC(UNLOCK_MSG,	unlockargs,	norep),
595 	PROC(GRANTED_MSG,	testargs,	norep),
596 	PROC(TEST_RES,		testres,	norep),
597 	PROC(LOCK_RES,		res,		norep),
598 	PROC(CANCEL_RES,	res,		norep),
599 	PROC(UNLOCK_RES,	res,		norep),
600 	PROC(GRANTED_RES,	res,		norep),
601 };
602 
603 static unsigned int nlm_version1_counts[ARRAY_SIZE(nlm_procedures)];
604 static const struct rpc_version	nlm_version1 = {
605 	.number		= 1,
606 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
607 	.procs		= nlm_procedures,
608 	.counts		= nlm_version1_counts,
609 };
610 
611 static unsigned int nlm_version3_counts[ARRAY_SIZE(nlm_procedures)];
612 static const struct rpc_version	nlm_version3 = {
613 	.number		= 3,
614 	.nrprocs	= ARRAY_SIZE(nlm_procedures),
615 	.procs		= nlm_procedures,
616 	.counts		= nlm_version3_counts,
617 };
618 
619 static const struct rpc_version	*nlm_versions[] = {
620 	[1] = &nlm_version1,
621 	[3] = &nlm_version3,
622 #ifdef CONFIG_LOCKD_V4
623 	[4] = &nlm_version4,
624 #endif
625 };
626 
627 static struct rpc_stat		nlm_rpc_stats;
628 
629 const struct rpc_program	nlm_program = {
630 	.name		= "lockd",
631 	.number		= NLM_PROGRAM,
632 	.nrvers		= ARRAY_SIZE(nlm_versions),
633 	.version	= nlm_versions,
634 	.stats		= &nlm_rpc_stats,
635 };
636