xref: /openbmc/linux/fs/lockd/clntxdr.c (revision 7fe2f639) 
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 #define NLMDBG_FACILITY		NLMDBG_XDR
19 
20 #if (NLMCLNT_OHSIZE > XDR_MAX_NETOBJ)
21 #  error "NLM host name cannot be larger than XDR_MAX_NETOBJ!"
22 #endif
23 
24 /*
25  * Declare the space requirements for NLM arguments and replies as
26  * number of 32bit-words
27  */
28 #define NLM_cookie_sz		(1+(NLM_MAXCOOKIELEN>>2))
29 #define NLM_caller_sz		(1+(NLMCLNT_OHSIZE>>2))
30 #define NLM_owner_sz		(1+(NLMCLNT_OHSIZE>>2))
31 #define NLM_fhandle_sz		(1+(NFS2_FHSIZE>>2))
32 #define NLM_lock_sz		(3+NLM_caller_sz+NLM_owner_sz+NLM_fhandle_sz)
33 #define NLM_holder_sz		(4+NLM_owner_sz)
34 
35 #define NLM_testargs_sz		(NLM_cookie_sz+1+NLM_lock_sz)
36 #define NLM_lockargs_sz		(NLM_cookie_sz+4+NLM_lock_sz)
37 #define NLM_cancargs_sz		(NLM_cookie_sz+2+NLM_lock_sz)
38 #define NLM_unlockargs_sz	(NLM_cookie_sz+NLM_lock_sz)
39 
40 #define NLM_testres_sz		(NLM_cookie_sz+1+NLM_holder_sz)
41 #define NLM_res_sz		(NLM_cookie_sz+1)
42 #define NLM_norep_sz		(0)
43 
44 
45 static s32 loff_t_to_s32(loff_t offset)
46 {
47 	s32 res;
48 
49 	if (offset >= NLM_OFFSET_MAX)
50 		res = NLM_OFFSET_MAX;
51 	else if (offset <= -NLM_OFFSET_MAX)
52 		res = -NLM_OFFSET_MAX;
53 	else
54 		res = offset;
55 	return res;
56 }
57 
58 static void nlm_compute_offsets(const struct nlm_lock *lock,
59 				u32 *l_offset, u32 *l_len)
60 {
61 	const struct file_lock *fl = &lock->fl;
62 
63 	BUG_ON(fl->fl_start > NLM_OFFSET_MAX);
64 	BUG_ON(fl->fl_end > NLM_OFFSET_MAX &&
65 				fl->fl_end != OFFSET_MAX);
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  * Handle decode buffer overflows out-of-line.
76  */
77 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
78 {
79 	dprintk("lockd: %s prematurely hit the end of our receive buffer. "
80 		"Remaining buffer length is %tu words.\n",
81 		func, xdr->end - xdr->p);
82 }
83 
84 
85 /*
86  * Encode/decode NLMv3 basic data types
87  *
88  * Basic NLMv3 data types are not defined in an IETF standards
89  * document.  X/Open has a description of these data types that
90  * is useful.  See Chapter 10 of "Protocols for Interworking:
91  * XNFS, Version 3W".
92  *
93  * Not all basic data types have their own encoding and decoding
94  * functions.  For run-time efficiency, some data types are encoded
95  * or decoded inline.
96  */
97 
98 static void encode_bool(struct xdr_stream *xdr, const int value)
99 {
100 	__be32 *p;
101 
102 	p = xdr_reserve_space(xdr, 4);
103 	*p = value ? xdr_one : xdr_zero;
104 }
105 
106 static void encode_int32(struct xdr_stream *xdr, const s32 value)
107 {
108 	__be32 *p;
109 
110 	p = xdr_reserve_space(xdr, 4);
111 	*p = cpu_to_be32(value);
112 }
113 
114 /*
115  *	typedef opaque netobj<MAXNETOBJ_SZ>
116  */
117 static void encode_netobj(struct xdr_stream *xdr,
118 			  const u8 *data, const unsigned int length)
119 {
120 	__be32 *p;
121 
122 	BUG_ON(length > XDR_MAX_NETOBJ);
123 	p = xdr_reserve_space(xdr, 4 + length);
124 	xdr_encode_opaque(p, data, length);
125 }
126 
127 static int decode_netobj(struct xdr_stream *xdr,
128 			 struct xdr_netobj *obj)
129 {
130 	u32 length;
131 	__be32 *p;
132 
133 	p = xdr_inline_decode(xdr, 4);
134 	if (unlikely(p == NULL))
135 		goto out_overflow;
136 	length = be32_to_cpup(p++);
137 	if (unlikely(length > XDR_MAX_NETOBJ))
138 		goto out_size;
139 	obj->len = length;
140 	obj->data = (u8 *)p;
141 	return 0;
142 out_size:
143 	dprintk("NFS: returned netobj was too long: %u\n", length);
144 	return -EIO;
145 out_overflow:
146 	print_overflow_msg(__func__, xdr);
147 	return -EIO;
148 }
149 
150 /*
151  *	netobj cookie;
152  */
153 static void encode_cookie(struct xdr_stream *xdr,
154 			  const struct nlm_cookie *cookie)
155 {
156 	BUG_ON(cookie->len > NLM_MAXCOOKIELEN);
157 	encode_netobj(xdr, (u8 *)&cookie->data, cookie->len);
158 }
159 
160 static int decode_cookie(struct xdr_stream *xdr,
161 			 struct nlm_cookie *cookie)
162 {
163 	u32 length;
164 	__be32 *p;
165 
166 	p = xdr_inline_decode(xdr, 4);
167 	if (unlikely(p == NULL))
168 		goto out_overflow;
169 	length = be32_to_cpup(p++);
170 	/* apparently HPUX can return empty cookies */
171 	if (length == 0)
172 		goto out_hpux;
173 	if (length > NLM_MAXCOOKIELEN)
174 		goto out_size;
175 	p = xdr_inline_decode(xdr, length);
176 	if (unlikely(p == NULL))
177 		goto out_overflow;
178 	cookie->len = length;
179 	memcpy(cookie->data, p, length);
180 	return 0;
181 out_hpux:
182 	cookie->len = 4;
183 	memset(cookie->data, 0, 4);
184 	return 0;
185 out_size:
186 	dprintk("NFS: returned cookie was too long: %u\n", length);
187 	return -EIO;
188 out_overflow:
189 	print_overflow_msg(__func__, xdr);
190 	return -EIO;
191 }
192 
193 /*
194  *	netobj fh;
195  */
196 static void encode_fh(struct xdr_stream *xdr, const struct nfs_fh *fh)
197 {
198 	BUG_ON(fh->size != NFS2_FHSIZE);
199 	encode_netobj(xdr, (u8 *)&fh->data, NFS2_FHSIZE);
200 }
201 
202 /*
203  *	enum nlm_stats {
204  *		LCK_GRANTED = 0,
205  *		LCK_DENIED = 1,
206  *		LCK_DENIED_NOLOCKS = 2,
207  *		LCK_BLOCKED = 3,
208  *		LCK_DENIED_GRACE_PERIOD = 4
209  *	};
210  *
211  *
212  *	struct nlm_stat {
213  *		nlm_stats stat;
214  *	};
215  *
216  * NB: we don't swap bytes for the NLM status values.  The upper
217  * layers deal directly with the status value in network byte
218  * order.
219  */
220 
221 static void encode_nlm_stat(struct xdr_stream *xdr,
222 			    const __be32 stat)
223 {
224 	__be32 *p;
225 
226 	BUG_ON(be32_to_cpu(stat) > NLM_LCK_DENIED_GRACE_PERIOD);
227 	p = xdr_reserve_space(xdr, 4);
228 	*p = stat;
229 }
230 
231 static int decode_nlm_stat(struct xdr_stream *xdr,
232 			   __be32 *stat)
233 {
234 	__be32 *p;
235 
236 	p = xdr_inline_decode(xdr, 4);
237 	if (unlikely(p == NULL))
238 		goto out_overflow;
239 	if (unlikely(*p > nlm_lck_denied_grace_period))
240 		goto out_enum;
241 	*stat = *p;
242 	return 0;
243 out_enum:
244 	dprintk("%s: server returned invalid nlm_stats value: %u\n",
245 		__func__, be32_to_cpup(p));
246 	return -EIO;
247 out_overflow:
248 	print_overflow_msg(__func__, xdr);
249 	return -EIO;
250 }
251 
252 /*
253  *	struct nlm_holder {
254  *		bool exclusive;
255  *		int uppid;
256  *		netobj oh;
257  *		unsigned l_offset;
258  *		unsigned l_len;
259  *	};
260  */
261 static void encode_nlm_holder(struct xdr_stream *xdr,
262 			      const struct nlm_res *result)
263 {
264 	const struct nlm_lock *lock = &result->lock;
265 	u32 l_offset, l_len;
266 	__be32 *p;
267 
268 	encode_bool(xdr, lock->fl.fl_type == F_RDLCK);
269 	encode_int32(xdr, lock->svid);
270 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
271 
272 	p = xdr_reserve_space(xdr, 4 + 4);
273 	nlm_compute_offsets(lock, &l_offset, &l_len);
274 	*p++ = cpu_to_be32(l_offset);
275 	*p   = cpu_to_be32(l_len);
276 }
277 
278 static int decode_nlm_holder(struct xdr_stream *xdr, struct nlm_res *result)
279 {
280 	struct nlm_lock *lock = &result->lock;
281 	struct file_lock *fl = &lock->fl;
282 	u32 exclusive, l_offset, l_len;
283 	int error;
284 	__be32 *p;
285 	s32 end;
286 
287 	memset(lock, 0, sizeof(*lock));
288 	locks_init_lock(fl);
289 
290 	p = xdr_inline_decode(xdr, 4 + 4);
291 	if (unlikely(p == NULL))
292 		goto out_overflow;
293 	exclusive = be32_to_cpup(p++);
294 	lock->svid = be32_to_cpup(p);
295 	fl->fl_pid = (pid_t)lock->svid;
296 
297 	error = decode_netobj(xdr, &lock->oh);
298 	if (unlikely(error))
299 		goto out;
300 
301 	p = xdr_inline_decode(xdr, 4 + 4);
302 	if (unlikely(p == NULL))
303 		goto out_overflow;
304 
305 	fl->fl_flags = FL_POSIX;
306 	fl->fl_type  = exclusive != 0 ? F_WRLCK : F_RDLCK;
307 	l_offset = be32_to_cpup(p++);
308 	l_len = be32_to_cpup(p);
309 	end = l_offset + l_len - 1;
310 
311 	fl->fl_start = (loff_t)l_offset;
312 	if (l_len == 0 || end < 0)
313 		fl->fl_end = OFFSET_MAX;
314 	else
315 		fl->fl_end = (loff_t)end;
316 	error = 0;
317 out:
318 	return error;
319 out_overflow:
320 	print_overflow_msg(__func__, xdr);
321 	return -EIO;
322 }
323 
324 /*
325  *	string caller_name<LM_MAXSTRLEN>;
326  */
327 static void encode_caller_name(struct xdr_stream *xdr, const char *name)
328 {
329 	/* NB: client-side does not set lock->len */
330 	u32 length = strlen(name);
331 	__be32 *p;
332 
333 	BUG_ON(length > NLM_MAXSTRLEN);
334 	p = xdr_reserve_space(xdr, 4 + length);
335 	xdr_encode_opaque(p, name, length);
336 }
337 
338 /*
339  *	struct nlm_lock {
340  *		string caller_name<LM_MAXSTRLEN>;
341  *		netobj fh;
342  *		netobj oh;
343  *		int uppid;
344  *		unsigned l_offset;
345  *		unsigned l_len;
346  *	};
347  */
348 static void encode_nlm_lock(struct xdr_stream *xdr,
349 			    const struct nlm_lock *lock)
350 {
351 	u32 l_offset, l_len;
352 	__be32 *p;
353 
354 	encode_caller_name(xdr, lock->caller);
355 	encode_fh(xdr, &lock->fh);
356 	encode_netobj(xdr, lock->oh.data, lock->oh.len);
357 
358 	p = xdr_reserve_space(xdr, 4 + 4 + 4);
359 	*p++ = cpu_to_be32(lock->svid);
360 
361 	nlm_compute_offsets(lock, &l_offset, &l_len);
362 	*p++ = cpu_to_be32(l_offset);
363 	*p   = cpu_to_be32(l_len);
364 }
365 
366 
367 /*
368  * NLMv3 XDR encode functions
369  *
370  * NLMv3 argument types are defined in Chapter 10 of The Open Group's
371  * "Protocols for Interworking: XNFS, Version 3W".
372  */
373 
374 /*
375  *	struct nlm_testargs {
376  *		netobj cookie;
377  *		bool exclusive;
378  *		struct nlm_lock alock;
379  *	};
380  */
381 static void nlm_xdr_enc_testargs(struct rpc_rqst *req,
382 				 struct xdr_stream *xdr,
383 				 const struct nlm_args *args)
384 {
385 	const struct nlm_lock *lock = &args->lock;
386 
387 	encode_cookie(xdr, &args->cookie);
388 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
389 	encode_nlm_lock(xdr, lock);
390 }
391 
392 /*
393  *	struct nlm_lockargs {
394  *		netobj cookie;
395  *		bool block;
396  *		bool exclusive;
397  *		struct nlm_lock alock;
398  *		bool reclaim;
399  *		int state;
400  *	};
401  */
402 static void nlm_xdr_enc_lockargs(struct rpc_rqst *req,
403 				 struct xdr_stream *xdr,
404 				 const struct nlm_args *args)
405 {
406 	const struct nlm_lock *lock = &args->lock;
407 
408 	encode_cookie(xdr, &args->cookie);
409 	encode_bool(xdr, args->block);
410 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
411 	encode_nlm_lock(xdr, lock);
412 	encode_bool(xdr, args->reclaim);
413 	encode_int32(xdr, args->state);
414 }
415 
416 /*
417  *	struct nlm_cancargs {
418  *		netobj cookie;
419  *		bool block;
420  *		bool exclusive;
421  *		struct nlm_lock alock;
422  *	};
423  */
424 static void nlm_xdr_enc_cancargs(struct rpc_rqst *req,
425 				 struct xdr_stream *xdr,
426 				 const struct nlm_args *args)
427 {
428 	const struct nlm_lock *lock = &args->lock;
429 
430 	encode_cookie(xdr, &args->cookie);
431 	encode_bool(xdr, args->block);
432 	encode_bool(xdr, lock->fl.fl_type == F_WRLCK);
433 	encode_nlm_lock(xdr, lock);
434 }
435 
436 /*
437  *	struct nlm_unlockargs {
438  *		netobj cookie;
439  *		struct nlm_lock alock;
440  *	};
441  */
442 static void nlm_xdr_enc_unlockargs(struct rpc_rqst *req,
443 				   struct xdr_stream *xdr,
444 				   const struct nlm_args *args)
445 {
446 	const struct nlm_lock *lock = &args->lock;
447 
448 	encode_cookie(xdr, &args->cookie);
449 	encode_nlm_lock(xdr, lock);
450 }
451 
452 /*
453  *	struct nlm_res {
454  *		netobj cookie;
455  *		nlm_stat stat;
456  *	};
457  */
458 static void nlm_xdr_enc_res(struct rpc_rqst *req,
459 			    struct xdr_stream *xdr,
460 			    const struct nlm_res *result)
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 struct nlm_res *result)
489 {
490 	encode_cookie(xdr, &result->cookie);
491 	encode_nlm_stat(xdr, result->status);
492 	encode_nlm_testrply(xdr, result);
493 }
494 
495 
496 /*
497  * NLMv3 XDR decode functions
498  *
499  * NLMv3 result types are defined in Chapter 10 of The Open Group's
500  * "Protocols for Interworking: XNFS, Version 3W".
501  */
502 
503 /*
504  *	union nlm_testrply switch (nlm_stats stat) {
505  *	case LCK_DENIED:
506  *		struct nlm_holder holder;
507  *	default:
508  *		void;
509  *	};
510  *
511  *	struct nlm_testres {
512  *		netobj cookie;
513  *		nlm_testrply test_stat;
514  *	};
515  */
516 static int decode_nlm_testrply(struct xdr_stream *xdr,
517 			       struct nlm_res *result)
518 {
519 	int error;
520 
521 	error = decode_nlm_stat(xdr, &result->status);
522 	if (unlikely(error))
523 		goto out;
524 	if (result->status == nlm_lck_denied)
525 		error = decode_nlm_holder(xdr, result);
526 out:
527 	return error;
528 }
529 
530 static int nlm_xdr_dec_testres(struct rpc_rqst *req,
531 			       struct xdr_stream *xdr,
532 			       struct nlm_res *result)
533 {
534 	int error;
535 
536 	error = decode_cookie(xdr, &result->cookie);
537 	if (unlikely(error))
538 		goto out;
539 	error = decode_nlm_testrply(xdr, result);
540 out:
541 	return error;
542 }
543 
544 /*
545  *	struct nlm_res {
546  *		netobj cookie;
547  *		nlm_stat stat;
548  *	};
549  */
550 static int nlm_xdr_dec_res(struct rpc_rqst *req,
551 			   struct xdr_stream *xdr,
552 			   struct nlm_res *result)
553 {
554 	int error;
555 
556 	error = decode_cookie(xdr, &result->cookie);
557 	if (unlikely(error))
558 		goto out;
559 	error = decode_nlm_stat(xdr, &result->status);
560 out:
561 	return error;
562 }
563 
564 
565 /*
566  * For NLM, a void procedure really returns nothing
567  */
568 #define nlm_xdr_dec_norep	NULL
569 
570 #define PROC(proc, argtype, restype)	\
571 [NLMPROC_##proc] = {							\
572 	.p_proc      = NLMPROC_##proc,					\
573 	.p_encode    = (kxdreproc_t)nlm_xdr_enc_##argtype,		\
574 	.p_decode    = (kxdrdproc_t)nlm_xdr_dec_##restype,		\
575 	.p_arglen    = NLM_##argtype##_sz,				\
576 	.p_replen    = NLM_##restype##_sz,				\
577 	.p_statidx   = NLMPROC_##proc,					\
578 	.p_name      = #proc,						\
579 	}
580 
581 static struct rpc_procinfo	nlm_procedures[] = {
582 	PROC(TEST,		testargs,	testres),
583 	PROC(LOCK,		lockargs,	res),
584 	PROC(CANCEL,		cancargs,	res),
585 	PROC(UNLOCK,		unlockargs,	res),
586 	PROC(GRANTED,		testargs,	res),
587 	PROC(TEST_MSG,		testargs,	norep),
588 	PROC(LOCK_MSG,		lockargs,	norep),
589 	PROC(CANCEL_MSG,	cancargs,	norep),
590 	PROC(UNLOCK_MSG,	unlockargs,	norep),
591 	PROC(GRANTED_MSG,	testargs,	norep),
592 	PROC(TEST_RES,		testres,	norep),
593 	PROC(LOCK_RES,		res,		norep),
594 	PROC(CANCEL_RES,	res,		norep),
595 	PROC(UNLOCK_RES,	res,		norep),
596 	PROC(GRANTED_RES,	res,		norep),
597 };
598 
599 static struct rpc_version	nlm_version1 = {
600 		.number		= 1,
601 		.nrprocs	= ARRAY_SIZE(nlm_procedures),
602 		.procs		= nlm_procedures,
603 };
604 
605 static struct rpc_version	nlm_version3 = {
606 		.number		= 3,
607 		.nrprocs	= ARRAY_SIZE(nlm_procedures),
608 		.procs		= nlm_procedures,
609 };
610 
611 static struct rpc_version	*nlm_versions[] = {
612 	[1] = &nlm_version1,
613 	[3] = &nlm_version3,
614 #ifdef CONFIG_LOCKD_V4
615 	[4] = &nlm_version4,
616 #endif
617 };
618 
619 static struct rpc_stat		nlm_rpc_stats;
620 
621 struct rpc_program		nlm_program = {
622 		.name		= "lockd",
623 		.number		= NLM_PROGRAM,
624 		.nrvers		= ARRAY_SIZE(nlm_versions),
625 		.version	= nlm_versions,
626 		.stats		= &nlm_rpc_stats,
627 };
628