xref: /openbmc/linux/fs/nfs/callback_xdr.c (revision d2ba09c1)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * linux/fs/nfs/callback_xdr.c
4  *
5  * Copyright (C) 2004 Trond Myklebust
6  *
7  * NFSv4 callback encode/decode procedures
8  */
9 #include <linux/kernel.h>
10 #include <linux/sunrpc/svc.h>
11 #include <linux/nfs4.h>
12 #include <linux/nfs_fs.h>
13 #include <linux/ratelimit.h>
14 #include <linux/printk.h>
15 #include <linux/slab.h>
16 #include <linux/sunrpc/bc_xprt.h>
17 #include "nfs4_fs.h"
18 #include "callback.h"
19 #include "internal.h"
20 #include "nfs4session.h"
21 
22 #define CB_OP_TAGLEN_MAXSZ		(512)
23 #define CB_OP_HDR_RES_MAXSZ		(2 * 4) // opcode, status
24 #define CB_OP_GETATTR_BITMAP_MAXSZ	(4 * 4) // bitmap length, 3 bitmaps
25 #define CB_OP_GETATTR_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ + \
26 					 CB_OP_GETATTR_BITMAP_MAXSZ + \
27 					 /* change, size, ctime, mtime */\
28 					 (2 + 2 + 3 + 3) * 4)
29 #define CB_OP_RECALL_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ)
30 
31 #if defined(CONFIG_NFS_V4_1)
32 #define CB_OP_LAYOUTRECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
33 #define CB_OP_DEVICENOTIFY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
34 #define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
35 					 NFS4_MAX_SESSIONID_LEN + \
36 					 (1 + 3) * 4) // seqid, 3 slotids
37 #define CB_OP_RECALLANY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
38 #define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
39 #define CB_OP_NOTIFY_LOCK_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
40 #endif /* CONFIG_NFS_V4_1 */
41 
42 #define NFSDBG_FACILITY NFSDBG_CALLBACK
43 
44 /* Internal error code */
45 #define NFS4ERR_RESOURCE_HDR	11050
46 
47 struct callback_op {
48 	__be32 (*process_op)(void *, void *, struct cb_process_state *);
49 	__be32 (*decode_args)(struct svc_rqst *, struct xdr_stream *, void *);
50 	__be32 (*encode_res)(struct svc_rqst *, struct xdr_stream *,
51 			const void *);
52 	long res_maxsize;
53 };
54 
55 static struct callback_op callback_ops[];
56 
57 static __be32 nfs4_callback_null(struct svc_rqst *rqstp)
58 {
59 	return htonl(NFS4_OK);
60 }
61 
62 static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p)
63 {
64 	return xdr_argsize_check(rqstp, p);
65 }
66 
67 static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p)
68 {
69 	return xdr_ressize_check(rqstp, p);
70 }
71 
72 static __be32 *read_buf(struct xdr_stream *xdr, size_t nbytes)
73 {
74 	__be32 *p;
75 
76 	p = xdr_inline_decode(xdr, nbytes);
77 	if (unlikely(p == NULL))
78 		printk(KERN_WARNING "NFS: NFSv4 callback reply buffer overflowed!\n");
79 	return p;
80 }
81 
82 static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len,
83 		const char **str, size_t maxlen)
84 {
85 	ssize_t err;
86 
87 	err = xdr_stream_decode_opaque_inline(xdr, (void **)str, maxlen);
88 	if (err < 0)
89 		return cpu_to_be32(NFS4ERR_RESOURCE);
90 	*len = err;
91 	return 0;
92 }
93 
94 static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
95 {
96 	__be32 *p;
97 
98 	p = read_buf(xdr, 4);
99 	if (unlikely(p == NULL))
100 		return htonl(NFS4ERR_RESOURCE);
101 	fh->size = ntohl(*p);
102 	if (fh->size > NFS4_FHSIZE)
103 		return htonl(NFS4ERR_BADHANDLE);
104 	p = read_buf(xdr, fh->size);
105 	if (unlikely(p == NULL))
106 		return htonl(NFS4ERR_RESOURCE);
107 	memcpy(&fh->data[0], p, fh->size);
108 	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
109 	return 0;
110 }
111 
112 static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
113 {
114 	__be32 *p;
115 	unsigned int attrlen;
116 
117 	p = read_buf(xdr, 4);
118 	if (unlikely(p == NULL))
119 		return htonl(NFS4ERR_RESOURCE);
120 	attrlen = ntohl(*p);
121 	p = read_buf(xdr, attrlen << 2);
122 	if (unlikely(p == NULL))
123 		return htonl(NFS4ERR_RESOURCE);
124 	if (likely(attrlen > 0))
125 		bitmap[0] = ntohl(*p++);
126 	if (attrlen > 1)
127 		bitmap[1] = ntohl(*p);
128 	return 0;
129 }
130 
131 static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
132 {
133 	__be32 *p;
134 
135 	p = read_buf(xdr, NFS4_STATEID_SIZE);
136 	if (unlikely(p == NULL))
137 		return htonl(NFS4ERR_RESOURCE);
138 	memcpy(stateid->data, p, NFS4_STATEID_SIZE);
139 	return 0;
140 }
141 
142 static __be32 decode_delegation_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
143 {
144 	stateid->type = NFS4_DELEGATION_STATEID_TYPE;
145 	return decode_stateid(xdr, stateid);
146 }
147 
148 static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
149 {
150 	__be32 *p;
151 	__be32 status;
152 
153 	status = decode_string(xdr, &hdr->taglen, &hdr->tag, CB_OP_TAGLEN_MAXSZ);
154 	if (unlikely(status != 0))
155 		return status;
156 	p = read_buf(xdr, 12);
157 	if (unlikely(p == NULL))
158 		return htonl(NFS4ERR_RESOURCE);
159 	hdr->minorversion = ntohl(*p++);
160 	/* Check for minor version support */
161 	if (hdr->minorversion <= NFS4_MAX_MINOR_VERSION) {
162 		hdr->cb_ident = ntohl(*p++); /* ignored by v4.1 and v4.2 */
163 	} else {
164 		pr_warn_ratelimited("NFS: %s: NFSv4 server callback with "
165 			"illegal minor version %u!\n",
166 			__func__, hdr->minorversion);
167 		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
168 	}
169 	hdr->nops = ntohl(*p);
170 	return 0;
171 }
172 
173 static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
174 {
175 	__be32 *p;
176 	p = read_buf(xdr, 4);
177 	if (unlikely(p == NULL))
178 		return htonl(NFS4ERR_RESOURCE_HDR);
179 	*op = ntohl(*p);
180 	return 0;
181 }
182 
183 static __be32 decode_getattr_args(struct svc_rqst *rqstp,
184 		struct xdr_stream *xdr, void *argp)
185 {
186 	struct cb_getattrargs *args = argp;
187 	__be32 status;
188 
189 	status = decode_fh(xdr, &args->fh);
190 	if (unlikely(status != 0))
191 		return status;
192 	return decode_bitmap(xdr, args->bitmap);
193 }
194 
195 static __be32 decode_recall_args(struct svc_rqst *rqstp,
196 		struct xdr_stream *xdr, void *argp)
197 {
198 	struct cb_recallargs *args = argp;
199 	__be32 *p;
200 	__be32 status;
201 
202 	status = decode_delegation_stateid(xdr, &args->stateid);
203 	if (unlikely(status != 0))
204 		return status;
205 	p = read_buf(xdr, 4);
206 	if (unlikely(p == NULL))
207 		return htonl(NFS4ERR_RESOURCE);
208 	args->truncate = ntohl(*p);
209 	return decode_fh(xdr, &args->fh);
210 }
211 
212 #if defined(CONFIG_NFS_V4_1)
213 static __be32 decode_layout_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
214 {
215 	stateid->type = NFS4_LAYOUT_STATEID_TYPE;
216 	return decode_stateid(xdr, stateid);
217 }
218 
219 static __be32 decode_layoutrecall_args(struct svc_rqst *rqstp,
220 				       struct xdr_stream *xdr, void *argp)
221 {
222 	struct cb_layoutrecallargs *args = argp;
223 	__be32 *p;
224 	__be32 status = 0;
225 	uint32_t iomode;
226 
227 	p = read_buf(xdr, 4 * sizeof(uint32_t));
228 	if (unlikely(p == NULL))
229 		return htonl(NFS4ERR_BADXDR);
230 
231 	args->cbl_layout_type = ntohl(*p++);
232 	/* Depite the spec's xdr, iomode really belongs in the FILE switch,
233 	 * as it is unusable and ignored with the other types.
234 	 */
235 	iomode = ntohl(*p++);
236 	args->cbl_layoutchanged = ntohl(*p++);
237 	args->cbl_recall_type = ntohl(*p++);
238 
239 	if (args->cbl_recall_type == RETURN_FILE) {
240 		args->cbl_range.iomode = iomode;
241 		status = decode_fh(xdr, &args->cbl_fh);
242 		if (unlikely(status != 0))
243 			return status;
244 
245 		p = read_buf(xdr, 2 * sizeof(uint64_t));
246 		if (unlikely(p == NULL))
247 			return htonl(NFS4ERR_BADXDR);
248 		p = xdr_decode_hyper(p, &args->cbl_range.offset);
249 		p = xdr_decode_hyper(p, &args->cbl_range.length);
250 		return decode_layout_stateid(xdr, &args->cbl_stateid);
251 	} else if (args->cbl_recall_type == RETURN_FSID) {
252 		p = read_buf(xdr, 2 * sizeof(uint64_t));
253 		if (unlikely(p == NULL))
254 			return htonl(NFS4ERR_BADXDR);
255 		p = xdr_decode_hyper(p, &args->cbl_fsid.major);
256 		p = xdr_decode_hyper(p, &args->cbl_fsid.minor);
257 	} else if (args->cbl_recall_type != RETURN_ALL)
258 		return htonl(NFS4ERR_BADXDR);
259 	return 0;
260 }
261 
262 static
263 __be32 decode_devicenotify_args(struct svc_rqst *rqstp,
264 				struct xdr_stream *xdr,
265 				void *argp)
266 {
267 	struct cb_devicenotifyargs *args = argp;
268 	__be32 *p;
269 	__be32 status = 0;
270 	u32 tmp;
271 	int n, i;
272 	args->ndevs = 0;
273 
274 	/* Num of device notifications */
275 	p = read_buf(xdr, sizeof(uint32_t));
276 	if (unlikely(p == NULL)) {
277 		status = htonl(NFS4ERR_BADXDR);
278 		goto out;
279 	}
280 	n = ntohl(*p++);
281 	if (n <= 0)
282 		goto out;
283 	if (n > ULONG_MAX / sizeof(*args->devs)) {
284 		status = htonl(NFS4ERR_BADXDR);
285 		goto out;
286 	}
287 
288 	args->devs = kmalloc_array(n, sizeof(*args->devs), GFP_KERNEL);
289 	if (!args->devs) {
290 		status = htonl(NFS4ERR_DELAY);
291 		goto out;
292 	}
293 
294 	/* Decode each dev notification */
295 	for (i = 0; i < n; i++) {
296 		struct cb_devicenotifyitem *dev = &args->devs[i];
297 
298 		p = read_buf(xdr, (4 * sizeof(uint32_t)) + NFS4_DEVICEID4_SIZE);
299 		if (unlikely(p == NULL)) {
300 			status = htonl(NFS4ERR_BADXDR);
301 			goto err;
302 		}
303 
304 		tmp = ntohl(*p++);	/* bitmap size */
305 		if (tmp != 1) {
306 			status = htonl(NFS4ERR_INVAL);
307 			goto err;
308 		}
309 		dev->cbd_notify_type = ntohl(*p++);
310 		if (dev->cbd_notify_type != NOTIFY_DEVICEID4_CHANGE &&
311 		    dev->cbd_notify_type != NOTIFY_DEVICEID4_DELETE) {
312 			status = htonl(NFS4ERR_INVAL);
313 			goto err;
314 		}
315 
316 		tmp = ntohl(*p++);	/* opaque size */
317 		if (((dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE) &&
318 		     (tmp != NFS4_DEVICEID4_SIZE + 8)) ||
319 		    ((dev->cbd_notify_type == NOTIFY_DEVICEID4_DELETE) &&
320 		     (tmp != NFS4_DEVICEID4_SIZE + 4))) {
321 			status = htonl(NFS4ERR_INVAL);
322 			goto err;
323 		}
324 		dev->cbd_layout_type = ntohl(*p++);
325 		memcpy(dev->cbd_dev_id.data, p, NFS4_DEVICEID4_SIZE);
326 		p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
327 
328 		if (dev->cbd_layout_type == NOTIFY_DEVICEID4_CHANGE) {
329 			p = read_buf(xdr, sizeof(uint32_t));
330 			if (unlikely(p == NULL)) {
331 				status = htonl(NFS4ERR_BADXDR);
332 				goto err;
333 			}
334 			dev->cbd_immediate = ntohl(*p++);
335 		} else {
336 			dev->cbd_immediate = 0;
337 		}
338 
339 		args->ndevs++;
340 
341 		dprintk("%s: type %d layout 0x%x immediate %d\n",
342 			__func__, dev->cbd_notify_type, dev->cbd_layout_type,
343 			dev->cbd_immediate);
344 	}
345 out:
346 	dprintk("%s: status %d ndevs %d\n",
347 		__func__, ntohl(status), args->ndevs);
348 	return status;
349 err:
350 	kfree(args->devs);
351 	goto out;
352 }
353 
354 static __be32 decode_sessionid(struct xdr_stream *xdr,
355 				 struct nfs4_sessionid *sid)
356 {
357 	__be32 *p;
358 
359 	p = read_buf(xdr, NFS4_MAX_SESSIONID_LEN);
360 	if (unlikely(p == NULL))
361 		return htonl(NFS4ERR_RESOURCE);
362 
363 	memcpy(sid->data, p, NFS4_MAX_SESSIONID_LEN);
364 	return 0;
365 }
366 
367 static __be32 decode_rc_list(struct xdr_stream *xdr,
368 			       struct referring_call_list *rc_list)
369 {
370 	__be32 *p;
371 	int i;
372 	__be32 status;
373 
374 	status = decode_sessionid(xdr, &rc_list->rcl_sessionid);
375 	if (status)
376 		goto out;
377 
378 	status = htonl(NFS4ERR_RESOURCE);
379 	p = read_buf(xdr, sizeof(uint32_t));
380 	if (unlikely(p == NULL))
381 		goto out;
382 
383 	rc_list->rcl_nrefcalls = ntohl(*p++);
384 	if (rc_list->rcl_nrefcalls) {
385 		p = read_buf(xdr,
386 			     rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
387 		if (unlikely(p == NULL))
388 			goto out;
389 		rc_list->rcl_refcalls = kmalloc_array(rc_list->rcl_nrefcalls,
390 						sizeof(*rc_list->rcl_refcalls),
391 						GFP_KERNEL);
392 		if (unlikely(rc_list->rcl_refcalls == NULL))
393 			goto out;
394 		for (i = 0; i < rc_list->rcl_nrefcalls; i++) {
395 			rc_list->rcl_refcalls[i].rc_sequenceid = ntohl(*p++);
396 			rc_list->rcl_refcalls[i].rc_slotid = ntohl(*p++);
397 		}
398 	}
399 	status = 0;
400 
401 out:
402 	return status;
403 }
404 
405 static __be32 decode_cb_sequence_args(struct svc_rqst *rqstp,
406 					struct xdr_stream *xdr,
407 					void *argp)
408 {
409 	struct cb_sequenceargs *args = argp;
410 	__be32 *p;
411 	int i;
412 	__be32 status;
413 
414 	status = decode_sessionid(xdr, &args->csa_sessionid);
415 	if (status)
416 		return status;
417 
418 	p = read_buf(xdr, 5 * sizeof(uint32_t));
419 	if (unlikely(p == NULL))
420 		return htonl(NFS4ERR_RESOURCE);
421 
422 	args->csa_addr = svc_addr(rqstp);
423 	args->csa_sequenceid = ntohl(*p++);
424 	args->csa_slotid = ntohl(*p++);
425 	args->csa_highestslotid = ntohl(*p++);
426 	args->csa_cachethis = ntohl(*p++);
427 	args->csa_nrclists = ntohl(*p++);
428 	args->csa_rclists = NULL;
429 	if (args->csa_nrclists) {
430 		args->csa_rclists = kmalloc_array(args->csa_nrclists,
431 						  sizeof(*args->csa_rclists),
432 						  GFP_KERNEL);
433 		if (unlikely(args->csa_rclists == NULL))
434 			return htonl(NFS4ERR_RESOURCE);
435 
436 		for (i = 0; i < args->csa_nrclists; i++) {
437 			status = decode_rc_list(xdr, &args->csa_rclists[i]);
438 			if (status) {
439 				args->csa_nrclists = i;
440 				goto out_free;
441 			}
442 		}
443 	}
444 	return 0;
445 
446 out_free:
447 	for (i = 0; i < args->csa_nrclists; i++)
448 		kfree(args->csa_rclists[i].rcl_refcalls);
449 	kfree(args->csa_rclists);
450 	return status;
451 }
452 
453 static __be32 decode_recallany_args(struct svc_rqst *rqstp,
454 				      struct xdr_stream *xdr,
455 				      void *argp)
456 {
457 	struct cb_recallanyargs *args = argp;
458 	uint32_t bitmap[2];
459 	__be32 *p, status;
460 
461 	p = read_buf(xdr, 4);
462 	if (unlikely(p == NULL))
463 		return htonl(NFS4ERR_BADXDR);
464 	args->craa_objs_to_keep = ntohl(*p++);
465 	status = decode_bitmap(xdr, bitmap);
466 	if (unlikely(status))
467 		return status;
468 	args->craa_type_mask = bitmap[0];
469 
470 	return 0;
471 }
472 
473 static __be32 decode_recallslot_args(struct svc_rqst *rqstp,
474 					struct xdr_stream *xdr,
475 					void *argp)
476 {
477 	struct cb_recallslotargs *args = argp;
478 	__be32 *p;
479 
480 	p = read_buf(xdr, 4);
481 	if (unlikely(p == NULL))
482 		return htonl(NFS4ERR_BADXDR);
483 	args->crsa_target_highest_slotid = ntohl(*p++);
484 	return 0;
485 }
486 
487 static __be32 decode_lockowner(struct xdr_stream *xdr, struct cb_notify_lock_args *args)
488 {
489 	__be32		*p;
490 	unsigned int	len;
491 
492 	p = read_buf(xdr, 12);
493 	if (unlikely(p == NULL))
494 		return htonl(NFS4ERR_BADXDR);
495 
496 	p = xdr_decode_hyper(p, &args->cbnl_owner.clientid);
497 	len = be32_to_cpu(*p);
498 
499 	p = read_buf(xdr, len);
500 	if (unlikely(p == NULL))
501 		return htonl(NFS4ERR_BADXDR);
502 
503 	/* Only try to decode if the length is right */
504 	if (len == 20) {
505 		p += 2;	/* skip "lock id:" */
506 		args->cbnl_owner.s_dev = be32_to_cpu(*p++);
507 		xdr_decode_hyper(p, &args->cbnl_owner.id);
508 		args->cbnl_valid = true;
509 	} else {
510 		args->cbnl_owner.s_dev = 0;
511 		args->cbnl_owner.id = 0;
512 		args->cbnl_valid = false;
513 	}
514 	return 0;
515 }
516 
517 static __be32 decode_notify_lock_args(struct svc_rqst *rqstp,
518 		struct xdr_stream *xdr, void *argp)
519 {
520 	struct cb_notify_lock_args *args = argp;
521 	__be32 status;
522 
523 	status = decode_fh(xdr, &args->cbnl_fh);
524 	if (unlikely(status != 0))
525 		return status;
526 	return decode_lockowner(xdr, args);
527 }
528 
529 #endif /* CONFIG_NFS_V4_1 */
530 
531 static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
532 {
533 	if (unlikely(xdr_stream_encode_opaque(xdr, str, len) < 0))
534 		return cpu_to_be32(NFS4ERR_RESOURCE);
535 	return 0;
536 }
537 
538 static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, size_t sz)
539 {
540 	if (xdr_stream_encode_uint32_array(xdr, bitmap, sz) < 0)
541 		return cpu_to_be32(NFS4ERR_RESOURCE);
542 	return 0;
543 }
544 
545 static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
546 {
547 	__be32 *p;
548 
549 	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
550 		return 0;
551 	p = xdr_reserve_space(xdr, 8);
552 	if (unlikely(!p))
553 		return htonl(NFS4ERR_RESOURCE);
554 	p = xdr_encode_hyper(p, change);
555 	return 0;
556 }
557 
558 static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
559 {
560 	__be32 *p;
561 
562 	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
563 		return 0;
564 	p = xdr_reserve_space(xdr, 8);
565 	if (unlikely(!p))
566 		return htonl(NFS4ERR_RESOURCE);
567 	p = xdr_encode_hyper(p, size);
568 	return 0;
569 }
570 
571 static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
572 {
573 	__be32 *p;
574 
575 	p = xdr_reserve_space(xdr, 12);
576 	if (unlikely(!p))
577 		return htonl(NFS4ERR_RESOURCE);
578 	p = xdr_encode_hyper(p, time->tv_sec);
579 	*p = htonl(time->tv_nsec);
580 	return 0;
581 }
582 
583 static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
584 {
585 	if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
586 		return 0;
587 	return encode_attr_time(xdr,time);
588 }
589 
590 static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
591 {
592 	if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
593 		return 0;
594 	return encode_attr_time(xdr,time);
595 }
596 
597 static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
598 {
599 	__be32 status;
600 
601 	hdr->status = xdr_reserve_space(xdr, 4);
602 	if (unlikely(hdr->status == NULL))
603 		return htonl(NFS4ERR_RESOURCE);
604 	status = encode_string(xdr, hdr->taglen, hdr->tag);
605 	if (unlikely(status != 0))
606 		return status;
607 	hdr->nops = xdr_reserve_space(xdr, 4);
608 	if (unlikely(hdr->nops == NULL))
609 		return htonl(NFS4ERR_RESOURCE);
610 	return 0;
611 }
612 
613 static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
614 {
615 	__be32 *p;
616 
617 	p = xdr_reserve_space(xdr, 8);
618 	if (unlikely(p == NULL))
619 		return htonl(NFS4ERR_RESOURCE_HDR);
620 	*p++ = htonl(op);
621 	*p = res;
622 	return 0;
623 }
624 
625 static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr,
626 		const void *resp)
627 {
628 	const struct cb_getattrres *res = resp;
629 	__be32 *savep = NULL;
630 	__be32 status = res->status;
631 
632 	if (unlikely(status != 0))
633 		goto out;
634 	status = encode_attr_bitmap(xdr, res->bitmap, ARRAY_SIZE(res->bitmap));
635 	if (unlikely(status != 0))
636 		goto out;
637 	status = cpu_to_be32(NFS4ERR_RESOURCE);
638 	savep = xdr_reserve_space(xdr, sizeof(*savep));
639 	if (unlikely(!savep))
640 		goto out;
641 	status = encode_attr_change(xdr, res->bitmap, res->change_attr);
642 	if (unlikely(status != 0))
643 		goto out;
644 	status = encode_attr_size(xdr, res->bitmap, res->size);
645 	if (unlikely(status != 0))
646 		goto out;
647 	status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
648 	if (unlikely(status != 0))
649 		goto out;
650 	status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
651 	*savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
652 out:
653 	return status;
654 }
655 
656 #if defined(CONFIG_NFS_V4_1)
657 
658 static __be32 encode_sessionid(struct xdr_stream *xdr,
659 				 const struct nfs4_sessionid *sid)
660 {
661 	__be32 *p;
662 
663 	p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
664 	if (unlikely(p == NULL))
665 		return htonl(NFS4ERR_RESOURCE);
666 
667 	memcpy(p, sid, NFS4_MAX_SESSIONID_LEN);
668 	return 0;
669 }
670 
671 static __be32 encode_cb_sequence_res(struct svc_rqst *rqstp,
672 				       struct xdr_stream *xdr,
673 				       const void *resp)
674 {
675 	const struct cb_sequenceres *res = resp;
676 	__be32 *p;
677 	__be32 status = res->csr_status;
678 
679 	if (unlikely(status != 0))
680 		return status;
681 
682 	status = encode_sessionid(xdr, &res->csr_sessionid);
683 	if (status)
684 		return status;
685 
686 	p = xdr_reserve_space(xdr, 4 * sizeof(uint32_t));
687 	if (unlikely(p == NULL))
688 		return htonl(NFS4ERR_RESOURCE);
689 
690 	*p++ = htonl(res->csr_sequenceid);
691 	*p++ = htonl(res->csr_slotid);
692 	*p++ = htonl(res->csr_highestslotid);
693 	*p++ = htonl(res->csr_target_highestslotid);
694 	return 0;
695 }
696 
697 static __be32
698 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
699 {
700 	if (op_nr == OP_CB_SEQUENCE) {
701 		if (nop != 0)
702 			return htonl(NFS4ERR_SEQUENCE_POS);
703 	} else {
704 		if (nop == 0)
705 			return htonl(NFS4ERR_OP_NOT_IN_SESSION);
706 	}
707 
708 	switch (op_nr) {
709 	case OP_CB_GETATTR:
710 	case OP_CB_RECALL:
711 	case OP_CB_SEQUENCE:
712 	case OP_CB_RECALL_ANY:
713 	case OP_CB_RECALL_SLOT:
714 	case OP_CB_LAYOUTRECALL:
715 	case OP_CB_NOTIFY_DEVICEID:
716 	case OP_CB_NOTIFY_LOCK:
717 		*op = &callback_ops[op_nr];
718 		break;
719 
720 	case OP_CB_NOTIFY:
721 	case OP_CB_PUSH_DELEG:
722 	case OP_CB_RECALLABLE_OBJ_AVAIL:
723 	case OP_CB_WANTS_CANCELLED:
724 		return htonl(NFS4ERR_NOTSUPP);
725 
726 	default:
727 		return htonl(NFS4ERR_OP_ILLEGAL);
728 	}
729 
730 	return htonl(NFS_OK);
731 }
732 
733 static void nfs4_callback_free_slot(struct nfs4_session *session,
734 		struct nfs4_slot *slot)
735 {
736 	struct nfs4_slot_table *tbl = &session->bc_slot_table;
737 
738 	spin_lock(&tbl->slot_tbl_lock);
739 	/*
740 	 * Let the state manager know callback processing done.
741 	 * A single slot, so highest used slotid is either 0 or -1
742 	 */
743 	nfs4_free_slot(tbl, slot);
744 	spin_unlock(&tbl->slot_tbl_lock);
745 }
746 
747 static void nfs4_cb_free_slot(struct cb_process_state *cps)
748 {
749 	if (cps->slot) {
750 		nfs4_callback_free_slot(cps->clp->cl_session, cps->slot);
751 		cps->slot = NULL;
752 	}
753 }
754 
755 #else /* CONFIG_NFS_V4_1 */
756 
757 static __be32
758 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
759 {
760 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
761 }
762 
763 static void nfs4_cb_free_slot(struct cb_process_state *cps)
764 {
765 }
766 #endif /* CONFIG_NFS_V4_1 */
767 
768 #ifdef CONFIG_NFS_V4_2
769 static __be32
770 preprocess_nfs42_op(int nop, unsigned int op_nr, struct callback_op **op)
771 {
772 	__be32 status = preprocess_nfs41_op(nop, op_nr, op);
773 	if (status != htonl(NFS4ERR_OP_ILLEGAL))
774 		return status;
775 
776 	if (op_nr == OP_CB_OFFLOAD)
777 		return htonl(NFS4ERR_NOTSUPP);
778 	return htonl(NFS4ERR_OP_ILLEGAL);
779 }
780 #else /* CONFIG_NFS_V4_2 */
781 static __be32
782 preprocess_nfs42_op(int nop, unsigned int op_nr, struct callback_op **op)
783 {
784 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
785 }
786 #endif /* CONFIG_NFS_V4_2 */
787 
788 static __be32
789 preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
790 {
791 	switch (op_nr) {
792 	case OP_CB_GETATTR:
793 	case OP_CB_RECALL:
794 		*op = &callback_ops[op_nr];
795 		break;
796 	default:
797 		return htonl(NFS4ERR_OP_ILLEGAL);
798 	}
799 
800 	return htonl(NFS_OK);
801 }
802 
803 static __be32 process_op(int nop, struct svc_rqst *rqstp,
804 		struct xdr_stream *xdr_in, void *argp,
805 		struct xdr_stream *xdr_out, void *resp,
806 		struct cb_process_state *cps)
807 {
808 	struct callback_op *op = &callback_ops[0];
809 	unsigned int op_nr;
810 	__be32 status;
811 	long maxlen;
812 	__be32 res;
813 
814 	status = decode_op_hdr(xdr_in, &op_nr);
815 	if (unlikely(status))
816 		return status;
817 
818 	switch (cps->minorversion) {
819 	case 0:
820 		status = preprocess_nfs4_op(op_nr, &op);
821 		break;
822 	case 1:
823 		status = preprocess_nfs41_op(nop, op_nr, &op);
824 		break;
825 	case 2:
826 		status = preprocess_nfs42_op(nop, op_nr, &op);
827 		break;
828 	default:
829 		status = htonl(NFS4ERR_MINOR_VERS_MISMATCH);
830 	}
831 
832 	if (status == htonl(NFS4ERR_OP_ILLEGAL))
833 		op_nr = OP_CB_ILLEGAL;
834 	if (status)
835 		goto encode_hdr;
836 
837 	if (cps->drc_status) {
838 		status = cps->drc_status;
839 		goto encode_hdr;
840 	}
841 
842 	maxlen = xdr_out->end - xdr_out->p;
843 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
844 		status = op->decode_args(rqstp, xdr_in, argp);
845 		if (likely(status == 0))
846 			status = op->process_op(argp, resp, cps);
847 	} else
848 		status = htonl(NFS4ERR_RESOURCE);
849 
850 encode_hdr:
851 	res = encode_op_hdr(xdr_out, op_nr, status);
852 	if (unlikely(res))
853 		return res;
854 	if (op->encode_res != NULL && status == 0)
855 		status = op->encode_res(rqstp, xdr_out, resp);
856 	return status;
857 }
858 
859 /*
860  * Decode, process and encode a COMPOUND
861  */
862 static __be32 nfs4_callback_compound(struct svc_rqst *rqstp)
863 {
864 	struct cb_compound_hdr_arg hdr_arg = { 0 };
865 	struct cb_compound_hdr_res hdr_res = { NULL };
866 	struct xdr_stream xdr_in, xdr_out;
867 	__be32 *p, status;
868 	struct cb_process_state cps = {
869 		.drc_status = 0,
870 		.clp = NULL,
871 		.net = SVC_NET(rqstp),
872 	};
873 	unsigned int nops = 0;
874 
875 	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
876 
877 	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
878 	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
879 
880 	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
881 	if (status == htonl(NFS4ERR_RESOURCE))
882 		return rpc_garbage_args;
883 
884 	if (hdr_arg.minorversion == 0) {
885 		cps.clp = nfs4_find_client_ident(SVC_NET(rqstp), hdr_arg.cb_ident);
886 		if (!cps.clp || !check_gss_callback_principal(cps.clp, rqstp))
887 			goto out_invalidcred;
888 	}
889 
890 	cps.minorversion = hdr_arg.minorversion;
891 	hdr_res.taglen = hdr_arg.taglen;
892 	hdr_res.tag = hdr_arg.tag;
893 	if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
894 		return rpc_system_err;
895 
896 	while (status == 0 && nops != hdr_arg.nops) {
897 		status = process_op(nops, rqstp, &xdr_in,
898 				    rqstp->rq_argp, &xdr_out, rqstp->rq_resp,
899 				    &cps);
900 		nops++;
901 	}
902 
903 	/* Buffer overflow in decode_ops_hdr or encode_ops_hdr. Return
904 	* resource error in cb_compound status without returning op */
905 	if (unlikely(status == htonl(NFS4ERR_RESOURCE_HDR))) {
906 		status = htonl(NFS4ERR_RESOURCE);
907 		nops--;
908 	}
909 
910 	*hdr_res.status = status;
911 	*hdr_res.nops = htonl(nops);
912 	nfs4_cb_free_slot(&cps);
913 	nfs_put_client(cps.clp);
914 	return rpc_success;
915 
916 out_invalidcred:
917 	pr_warn_ratelimited("NFS: NFSv4 callback contains invalid cred\n");
918 	return rpc_autherr_badcred;
919 }
920 
921 /*
922  * Define NFS4 callback COMPOUND ops.
923  */
924 static struct callback_op callback_ops[] = {
925 	[0] = {
926 		.res_maxsize = CB_OP_HDR_RES_MAXSZ,
927 	},
928 	[OP_CB_GETATTR] = {
929 		.process_op = nfs4_callback_getattr,
930 		.decode_args = decode_getattr_args,
931 		.encode_res = encode_getattr_res,
932 		.res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
933 	},
934 	[OP_CB_RECALL] = {
935 		.process_op = nfs4_callback_recall,
936 		.decode_args = decode_recall_args,
937 		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
938 	},
939 #if defined(CONFIG_NFS_V4_1)
940 	[OP_CB_LAYOUTRECALL] = {
941 		.process_op = nfs4_callback_layoutrecall,
942 		.decode_args = decode_layoutrecall_args,
943 		.res_maxsize = CB_OP_LAYOUTRECALL_RES_MAXSZ,
944 	},
945 	[OP_CB_NOTIFY_DEVICEID] = {
946 		.process_op = nfs4_callback_devicenotify,
947 		.decode_args = decode_devicenotify_args,
948 		.res_maxsize = CB_OP_DEVICENOTIFY_RES_MAXSZ,
949 	},
950 	[OP_CB_SEQUENCE] = {
951 		.process_op = nfs4_callback_sequence,
952 		.decode_args = decode_cb_sequence_args,
953 		.encode_res = encode_cb_sequence_res,
954 		.res_maxsize = CB_OP_SEQUENCE_RES_MAXSZ,
955 	},
956 	[OP_CB_RECALL_ANY] = {
957 		.process_op = nfs4_callback_recallany,
958 		.decode_args = decode_recallany_args,
959 		.res_maxsize = CB_OP_RECALLANY_RES_MAXSZ,
960 	},
961 	[OP_CB_RECALL_SLOT] = {
962 		.process_op = nfs4_callback_recallslot,
963 		.decode_args = decode_recallslot_args,
964 		.res_maxsize = CB_OP_RECALLSLOT_RES_MAXSZ,
965 	},
966 	[OP_CB_NOTIFY_LOCK] = {
967 		.process_op = nfs4_callback_notify_lock,
968 		.decode_args = decode_notify_lock_args,
969 		.res_maxsize = CB_OP_NOTIFY_LOCK_RES_MAXSZ,
970 	},
971 #endif /* CONFIG_NFS_V4_1 */
972 };
973 
974 /*
975  * Define NFS4 callback procedures
976  */
977 static const struct svc_procedure nfs4_callback_procedures1[] = {
978 	[CB_NULL] = {
979 		.pc_func = nfs4_callback_null,
980 		.pc_decode = nfs4_decode_void,
981 		.pc_encode = nfs4_encode_void,
982 		.pc_xdrressize = 1,
983 	},
984 	[CB_COMPOUND] = {
985 		.pc_func = nfs4_callback_compound,
986 		.pc_encode = nfs4_encode_void,
987 		.pc_argsize = 256,
988 		.pc_ressize = 256,
989 		.pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
990 	}
991 };
992 
993 static unsigned int nfs4_callback_count1[ARRAY_SIZE(nfs4_callback_procedures1)];
994 const struct svc_version nfs4_callback_version1 = {
995 	.vs_vers = 1,
996 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
997 	.vs_proc = nfs4_callback_procedures1,
998 	.vs_count = nfs4_callback_count1,
999 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
1000 	.vs_dispatch = NULL,
1001 	.vs_hidden = true,
1002 	.vs_need_cong_ctrl = true,
1003 };
1004 
1005 static unsigned int nfs4_callback_count4[ARRAY_SIZE(nfs4_callback_procedures1)];
1006 const struct svc_version nfs4_callback_version4 = {
1007 	.vs_vers = 4,
1008 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
1009 	.vs_proc = nfs4_callback_procedures1,
1010 	.vs_count = nfs4_callback_count4,
1011 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
1012 	.vs_dispatch = NULL,
1013 	.vs_hidden = true,
1014 	.vs_need_cong_ctrl = true,
1015 };
1016