xref: /linux/fs/nfs/callback_xdr.c (revision e5c86679d5e864947a52fb31e45a425dea3e7fa9)
1 /*
2  * linux/fs/nfs/callback_xdr.c
3  *
4  * Copyright (C) 2004 Trond Myklebust
5  *
6  * NFSv4 callback encode/decode procedures
7  */
8 #include <linux/kernel.h>
9 #include <linux/sunrpc/svc.h>
10 #include <linux/nfs4.h>
11 #include <linux/nfs_fs.h>
12 #include <linux/ratelimit.h>
13 #include <linux/printk.h>
14 #include <linux/slab.h>
15 #include <linux/sunrpc/bc_xprt.h>
16 #include "nfs4_fs.h"
17 #include "callback.h"
18 #include "internal.h"
19 #include "nfs4session.h"
20 
21 #define CB_OP_TAGLEN_MAXSZ		(512)
22 #define CB_OP_HDR_RES_MAXSZ		(2 * 4) // opcode, status
23 #define CB_OP_GETATTR_BITMAP_MAXSZ	(4 * 4) // bitmap length, 3 bitmaps
24 #define CB_OP_GETATTR_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ + \
25 					 CB_OP_GETATTR_BITMAP_MAXSZ + \
26 					 /* change, size, ctime, mtime */\
27 					 (2 + 2 + 3 + 3) * 4)
28 #define CB_OP_RECALL_RES_MAXSZ		(CB_OP_HDR_RES_MAXSZ)
29 
30 #if defined(CONFIG_NFS_V4_1)
31 #define CB_OP_LAYOUTRECALL_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
32 #define CB_OP_DEVICENOTIFY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
33 #define CB_OP_SEQUENCE_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ + \
34 					 NFS4_MAX_SESSIONID_LEN + \
35 					 (1 + 3) * 4) // seqid, 3 slotids
36 #define CB_OP_RECALLANY_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
37 #define CB_OP_RECALLSLOT_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
38 #define CB_OP_NOTIFY_LOCK_RES_MAXSZ	(CB_OP_HDR_RES_MAXSZ)
39 #endif /* CONFIG_NFS_V4_1 */
40 
41 #define NFSDBG_FACILITY NFSDBG_CALLBACK
42 
43 /* Internal error code */
44 #define NFS4ERR_RESOURCE_HDR	11050
45 
46 typedef __be32 (*callback_process_op_t)(void *, void *,
47 					struct cb_process_state *);
48 typedef __be32 (*callback_decode_arg_t)(struct svc_rqst *, struct xdr_stream *, void *);
49 typedef __be32 (*callback_encode_res_t)(struct svc_rqst *, struct xdr_stream *, void *);
50 
51 
52 struct callback_op {
53 	callback_process_op_t process_op;
54 	callback_decode_arg_t decode_args;
55 	callback_encode_res_t encode_res;
56 	long res_maxsize;
57 };
58 
59 static struct callback_op callback_ops[];
60 
61 static __be32 nfs4_callback_null(struct svc_rqst *rqstp, void *argp, void *resp)
62 {
63 	return htonl(NFS4_OK);
64 }
65 
66 static int nfs4_decode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
67 {
68 	return xdr_argsize_check(rqstp, p);
69 }
70 
71 static int nfs4_encode_void(struct svc_rqst *rqstp, __be32 *p, void *dummy)
72 {
73 	return xdr_ressize_check(rqstp, p);
74 }
75 
76 static __be32 *read_buf(struct xdr_stream *xdr, size_t nbytes)
77 {
78 	__be32 *p;
79 
80 	p = xdr_inline_decode(xdr, nbytes);
81 	if (unlikely(p == NULL))
82 		printk(KERN_WARNING "NFS: NFSv4 callback reply buffer overflowed!\n");
83 	return p;
84 }
85 
86 static __be32 decode_string(struct xdr_stream *xdr, unsigned int *len,
87 		const char **str, size_t maxlen)
88 {
89 	ssize_t err;
90 
91 	err = xdr_stream_decode_opaque_inline(xdr, (void **)str, maxlen);
92 	if (err < 0)
93 		return cpu_to_be32(NFS4ERR_RESOURCE);
94 	*len = err;
95 	return 0;
96 }
97 
98 static __be32 decode_fh(struct xdr_stream *xdr, struct nfs_fh *fh)
99 {
100 	__be32 *p;
101 
102 	p = read_buf(xdr, 4);
103 	if (unlikely(p == NULL))
104 		return htonl(NFS4ERR_RESOURCE);
105 	fh->size = ntohl(*p);
106 	if (fh->size > NFS4_FHSIZE)
107 		return htonl(NFS4ERR_BADHANDLE);
108 	p = read_buf(xdr, fh->size);
109 	if (unlikely(p == NULL))
110 		return htonl(NFS4ERR_RESOURCE);
111 	memcpy(&fh->data[0], p, fh->size);
112 	memset(&fh->data[fh->size], 0, sizeof(fh->data) - fh->size);
113 	return 0;
114 }
115 
116 static __be32 decode_bitmap(struct xdr_stream *xdr, uint32_t *bitmap)
117 {
118 	__be32 *p;
119 	unsigned int attrlen;
120 
121 	p = read_buf(xdr, 4);
122 	if (unlikely(p == NULL))
123 		return htonl(NFS4ERR_RESOURCE);
124 	attrlen = ntohl(*p);
125 	p = read_buf(xdr, attrlen << 2);
126 	if (unlikely(p == NULL))
127 		return htonl(NFS4ERR_RESOURCE);
128 	if (likely(attrlen > 0))
129 		bitmap[0] = ntohl(*p++);
130 	if (attrlen > 1)
131 		bitmap[1] = ntohl(*p);
132 	return 0;
133 }
134 
135 static __be32 decode_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
136 {
137 	__be32 *p;
138 
139 	p = read_buf(xdr, NFS4_STATEID_SIZE);
140 	if (unlikely(p == NULL))
141 		return htonl(NFS4ERR_RESOURCE);
142 	memcpy(stateid->data, p, NFS4_STATEID_SIZE);
143 	return 0;
144 }
145 
146 static __be32 decode_delegation_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
147 {
148 	stateid->type = NFS4_DELEGATION_STATEID_TYPE;
149 	return decode_stateid(xdr, stateid);
150 }
151 
152 static __be32 decode_compound_hdr_arg(struct xdr_stream *xdr, struct cb_compound_hdr_arg *hdr)
153 {
154 	__be32 *p;
155 	__be32 status;
156 
157 	status = decode_string(xdr, &hdr->taglen, &hdr->tag, CB_OP_TAGLEN_MAXSZ);
158 	if (unlikely(status != 0))
159 		return status;
160 	p = read_buf(xdr, 12);
161 	if (unlikely(p == NULL))
162 		return htonl(NFS4ERR_RESOURCE);
163 	hdr->minorversion = ntohl(*p++);
164 	/* Check for minor version support */
165 	if (hdr->minorversion <= NFS4_MAX_MINOR_VERSION) {
166 		hdr->cb_ident = ntohl(*p++); /* ignored by v4.1 and v4.2 */
167 	} else {
168 		pr_warn_ratelimited("NFS: %s: NFSv4 server callback with "
169 			"illegal minor version %u!\n",
170 			__func__, hdr->minorversion);
171 		return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
172 	}
173 	hdr->nops = ntohl(*p);
174 	dprintk("%s: minorversion %d nops %d\n", __func__,
175 		hdr->minorversion, hdr->nops);
176 	return 0;
177 }
178 
179 static __be32 decode_op_hdr(struct xdr_stream *xdr, unsigned int *op)
180 {
181 	__be32 *p;
182 	p = read_buf(xdr, 4);
183 	if (unlikely(p == NULL))
184 		return htonl(NFS4ERR_RESOURCE_HDR);
185 	*op = ntohl(*p);
186 	return 0;
187 }
188 
189 static __be32 decode_getattr_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_getattrargs *args)
190 {
191 	__be32 status;
192 
193 	status = decode_fh(xdr, &args->fh);
194 	if (unlikely(status != 0))
195 		goto out;
196 	status = decode_bitmap(xdr, args->bitmap);
197 out:
198 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
199 	return status;
200 }
201 
202 static __be32 decode_recall_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_recallargs *args)
203 {
204 	__be32 *p;
205 	__be32 status;
206 
207 	status = decode_delegation_stateid(xdr, &args->stateid);
208 	if (unlikely(status != 0))
209 		goto out;
210 	p = read_buf(xdr, 4);
211 	if (unlikely(p == NULL)) {
212 		status = htonl(NFS4ERR_RESOURCE);
213 		goto out;
214 	}
215 	args->truncate = ntohl(*p);
216 	status = decode_fh(xdr, &args->fh);
217 out:
218 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
219 	return status;
220 }
221 
222 #if defined(CONFIG_NFS_V4_1)
223 static __be32 decode_layout_stateid(struct xdr_stream *xdr, nfs4_stateid *stateid)
224 {
225 	stateid->type = NFS4_LAYOUT_STATEID_TYPE;
226 	return decode_stateid(xdr, stateid);
227 }
228 
229 static __be32 decode_layoutrecall_args(struct svc_rqst *rqstp,
230 				       struct xdr_stream *xdr,
231 				       struct cb_layoutrecallargs *args)
232 {
233 	__be32 *p;
234 	__be32 status = 0;
235 	uint32_t iomode;
236 
237 	p = read_buf(xdr, 4 * sizeof(uint32_t));
238 	if (unlikely(p == NULL)) {
239 		status = htonl(NFS4ERR_BADXDR);
240 		goto out;
241 	}
242 
243 	args->cbl_layout_type = ntohl(*p++);
244 	/* Depite the spec's xdr, iomode really belongs in the FILE switch,
245 	 * as it is unusable and ignored with the other types.
246 	 */
247 	iomode = ntohl(*p++);
248 	args->cbl_layoutchanged = ntohl(*p++);
249 	args->cbl_recall_type = ntohl(*p++);
250 
251 	if (args->cbl_recall_type == RETURN_FILE) {
252 		args->cbl_range.iomode = iomode;
253 		status = decode_fh(xdr, &args->cbl_fh);
254 		if (unlikely(status != 0))
255 			goto out;
256 
257 		p = read_buf(xdr, 2 * sizeof(uint64_t));
258 		if (unlikely(p == NULL)) {
259 			status = htonl(NFS4ERR_BADXDR);
260 			goto out;
261 		}
262 		p = xdr_decode_hyper(p, &args->cbl_range.offset);
263 		p = xdr_decode_hyper(p, &args->cbl_range.length);
264 		status = decode_layout_stateid(xdr, &args->cbl_stateid);
265 		if (unlikely(status != 0))
266 			goto out;
267 	} else if (args->cbl_recall_type == RETURN_FSID) {
268 		p = read_buf(xdr, 2 * sizeof(uint64_t));
269 		if (unlikely(p == NULL)) {
270 			status = htonl(NFS4ERR_BADXDR);
271 			goto out;
272 		}
273 		p = xdr_decode_hyper(p, &args->cbl_fsid.major);
274 		p = xdr_decode_hyper(p, &args->cbl_fsid.minor);
275 	} else if (args->cbl_recall_type != RETURN_ALL) {
276 		status = htonl(NFS4ERR_BADXDR);
277 		goto out;
278 	}
279 	dprintk("%s: ltype 0x%x iomode %d changed %d recall_type %d\n",
280 		__func__,
281 		args->cbl_layout_type, iomode,
282 		args->cbl_layoutchanged, args->cbl_recall_type);
283 out:
284 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
285 	return status;
286 }
287 
288 static
289 __be32 decode_devicenotify_args(struct svc_rqst *rqstp,
290 				struct xdr_stream *xdr,
291 				struct cb_devicenotifyargs *args)
292 {
293 	__be32 *p;
294 	__be32 status = 0;
295 	u32 tmp;
296 	int n, i;
297 	args->ndevs = 0;
298 
299 	/* Num of device notifications */
300 	p = read_buf(xdr, sizeof(uint32_t));
301 	if (unlikely(p == NULL)) {
302 		status = htonl(NFS4ERR_BADXDR);
303 		goto out;
304 	}
305 	n = ntohl(*p++);
306 	if (n <= 0)
307 		goto out;
308 	if (n > ULONG_MAX / sizeof(*args->devs)) {
309 		status = htonl(NFS4ERR_BADXDR);
310 		goto out;
311 	}
312 
313 	args->devs = kmalloc_array(n, sizeof(*args->devs), GFP_KERNEL);
314 	if (!args->devs) {
315 		status = htonl(NFS4ERR_DELAY);
316 		goto out;
317 	}
318 
319 	/* Decode each dev notification */
320 	for (i = 0; i < n; i++) {
321 		struct cb_devicenotifyitem *dev = &args->devs[i];
322 
323 		p = read_buf(xdr, (4 * sizeof(uint32_t)) + NFS4_DEVICEID4_SIZE);
324 		if (unlikely(p == NULL)) {
325 			status = htonl(NFS4ERR_BADXDR);
326 			goto err;
327 		}
328 
329 		tmp = ntohl(*p++);	/* bitmap size */
330 		if (tmp != 1) {
331 			status = htonl(NFS4ERR_INVAL);
332 			goto err;
333 		}
334 		dev->cbd_notify_type = ntohl(*p++);
335 		if (dev->cbd_notify_type != NOTIFY_DEVICEID4_CHANGE &&
336 		    dev->cbd_notify_type != NOTIFY_DEVICEID4_DELETE) {
337 			status = htonl(NFS4ERR_INVAL);
338 			goto err;
339 		}
340 
341 		tmp = ntohl(*p++);	/* opaque size */
342 		if (((dev->cbd_notify_type == NOTIFY_DEVICEID4_CHANGE) &&
343 		     (tmp != NFS4_DEVICEID4_SIZE + 8)) ||
344 		    ((dev->cbd_notify_type == NOTIFY_DEVICEID4_DELETE) &&
345 		     (tmp != NFS4_DEVICEID4_SIZE + 4))) {
346 			status = htonl(NFS4ERR_INVAL);
347 			goto err;
348 		}
349 		dev->cbd_layout_type = ntohl(*p++);
350 		memcpy(dev->cbd_dev_id.data, p, NFS4_DEVICEID4_SIZE);
351 		p += XDR_QUADLEN(NFS4_DEVICEID4_SIZE);
352 
353 		if (dev->cbd_layout_type == NOTIFY_DEVICEID4_CHANGE) {
354 			p = read_buf(xdr, sizeof(uint32_t));
355 			if (unlikely(p == NULL)) {
356 				status = htonl(NFS4ERR_BADXDR);
357 				goto err;
358 			}
359 			dev->cbd_immediate = ntohl(*p++);
360 		} else {
361 			dev->cbd_immediate = 0;
362 		}
363 
364 		args->ndevs++;
365 
366 		dprintk("%s: type %d layout 0x%x immediate %d\n",
367 			__func__, dev->cbd_notify_type, dev->cbd_layout_type,
368 			dev->cbd_immediate);
369 	}
370 out:
371 	dprintk("%s: status %d ndevs %d\n",
372 		__func__, ntohl(status), args->ndevs);
373 	return status;
374 err:
375 	kfree(args->devs);
376 	goto out;
377 }
378 
379 static __be32 decode_sessionid(struct xdr_stream *xdr,
380 				 struct nfs4_sessionid *sid)
381 {
382 	__be32 *p;
383 
384 	p = read_buf(xdr, NFS4_MAX_SESSIONID_LEN);
385 	if (unlikely(p == NULL))
386 		return htonl(NFS4ERR_RESOURCE);
387 
388 	memcpy(sid->data, p, NFS4_MAX_SESSIONID_LEN);
389 	return 0;
390 }
391 
392 static __be32 decode_rc_list(struct xdr_stream *xdr,
393 			       struct referring_call_list *rc_list)
394 {
395 	__be32 *p;
396 	int i;
397 	__be32 status;
398 
399 	status = decode_sessionid(xdr, &rc_list->rcl_sessionid);
400 	if (status)
401 		goto out;
402 
403 	status = htonl(NFS4ERR_RESOURCE);
404 	p = read_buf(xdr, sizeof(uint32_t));
405 	if (unlikely(p == NULL))
406 		goto out;
407 
408 	rc_list->rcl_nrefcalls = ntohl(*p++);
409 	if (rc_list->rcl_nrefcalls) {
410 		p = read_buf(xdr,
411 			     rc_list->rcl_nrefcalls * 2 * sizeof(uint32_t));
412 		if (unlikely(p == NULL))
413 			goto out;
414 		rc_list->rcl_refcalls = kmalloc_array(rc_list->rcl_nrefcalls,
415 						sizeof(*rc_list->rcl_refcalls),
416 						GFP_KERNEL);
417 		if (unlikely(rc_list->rcl_refcalls == NULL))
418 			goto out;
419 		for (i = 0; i < rc_list->rcl_nrefcalls; i++) {
420 			rc_list->rcl_refcalls[i].rc_sequenceid = ntohl(*p++);
421 			rc_list->rcl_refcalls[i].rc_slotid = ntohl(*p++);
422 		}
423 	}
424 	status = 0;
425 
426 out:
427 	return status;
428 }
429 
430 static __be32 decode_cb_sequence_args(struct svc_rqst *rqstp,
431 					struct xdr_stream *xdr,
432 					struct cb_sequenceargs *args)
433 {
434 	__be32 *p;
435 	int i;
436 	__be32 status;
437 
438 	status = decode_sessionid(xdr, &args->csa_sessionid);
439 	if (status)
440 		goto out;
441 
442 	status = htonl(NFS4ERR_RESOURCE);
443 	p = read_buf(xdr, 5 * sizeof(uint32_t));
444 	if (unlikely(p == NULL))
445 		goto out;
446 
447 	args->csa_addr = svc_addr(rqstp);
448 	args->csa_sequenceid = ntohl(*p++);
449 	args->csa_slotid = ntohl(*p++);
450 	args->csa_highestslotid = ntohl(*p++);
451 	args->csa_cachethis = ntohl(*p++);
452 	args->csa_nrclists = ntohl(*p++);
453 	args->csa_rclists = NULL;
454 	if (args->csa_nrclists) {
455 		args->csa_rclists = kmalloc_array(args->csa_nrclists,
456 						  sizeof(*args->csa_rclists),
457 						  GFP_KERNEL);
458 		if (unlikely(args->csa_rclists == NULL))
459 			goto out;
460 
461 		for (i = 0; i < args->csa_nrclists; i++) {
462 			status = decode_rc_list(xdr, &args->csa_rclists[i]);
463 			if (status) {
464 				args->csa_nrclists = i;
465 				goto out_free;
466 			}
467 		}
468 	}
469 	status = 0;
470 
471 	dprintk("%s: sessionid %x:%x:%x:%x sequenceid %u slotid %u "
472 		"highestslotid %u cachethis %d nrclists %u\n",
473 		__func__,
474 		((u32 *)&args->csa_sessionid)[0],
475 		((u32 *)&args->csa_sessionid)[1],
476 		((u32 *)&args->csa_sessionid)[2],
477 		((u32 *)&args->csa_sessionid)[3],
478 		args->csa_sequenceid, args->csa_slotid,
479 		args->csa_highestslotid, args->csa_cachethis,
480 		args->csa_nrclists);
481 out:
482 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
483 	return status;
484 
485 out_free:
486 	for (i = 0; i < args->csa_nrclists; i++)
487 		kfree(args->csa_rclists[i].rcl_refcalls);
488 	kfree(args->csa_rclists);
489 	goto out;
490 }
491 
492 static __be32 decode_recallany_args(struct svc_rqst *rqstp,
493 				      struct xdr_stream *xdr,
494 				      struct cb_recallanyargs *args)
495 {
496 	uint32_t bitmap[2];
497 	__be32 *p, status;
498 
499 	p = read_buf(xdr, 4);
500 	if (unlikely(p == NULL))
501 		return htonl(NFS4ERR_BADXDR);
502 	args->craa_objs_to_keep = ntohl(*p++);
503 	status = decode_bitmap(xdr, bitmap);
504 	if (unlikely(status))
505 		return status;
506 	args->craa_type_mask = bitmap[0];
507 
508 	return 0;
509 }
510 
511 static __be32 decode_recallslot_args(struct svc_rqst *rqstp,
512 					struct xdr_stream *xdr,
513 					struct cb_recallslotargs *args)
514 {
515 	__be32 *p;
516 
517 	p = read_buf(xdr, 4);
518 	if (unlikely(p == NULL))
519 		return htonl(NFS4ERR_BADXDR);
520 	args->crsa_target_highest_slotid = ntohl(*p++);
521 	return 0;
522 }
523 
524 static __be32 decode_lockowner(struct xdr_stream *xdr, struct cb_notify_lock_args *args)
525 {
526 	__be32		*p;
527 	unsigned int	len;
528 
529 	p = read_buf(xdr, 12);
530 	if (unlikely(p == NULL))
531 		return htonl(NFS4ERR_BADXDR);
532 
533 	p = xdr_decode_hyper(p, &args->cbnl_owner.clientid);
534 	len = be32_to_cpu(*p);
535 
536 	p = read_buf(xdr, len);
537 	if (unlikely(p == NULL))
538 		return htonl(NFS4ERR_BADXDR);
539 
540 	/* Only try to decode if the length is right */
541 	if (len == 20) {
542 		p += 2;	/* skip "lock id:" */
543 		args->cbnl_owner.s_dev = be32_to_cpu(*p++);
544 		xdr_decode_hyper(p, &args->cbnl_owner.id);
545 		args->cbnl_valid = true;
546 	} else {
547 		args->cbnl_owner.s_dev = 0;
548 		args->cbnl_owner.id = 0;
549 		args->cbnl_valid = false;
550 	}
551 	return 0;
552 }
553 
554 static __be32 decode_notify_lock_args(struct svc_rqst *rqstp, struct xdr_stream *xdr, struct cb_notify_lock_args *args)
555 {
556 	__be32 status;
557 
558 	status = decode_fh(xdr, &args->cbnl_fh);
559 	if (unlikely(status != 0))
560 		goto out;
561 	status = decode_lockowner(xdr, args);
562 out:
563 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
564 	return status;
565 }
566 
567 #endif /* CONFIG_NFS_V4_1 */
568 
569 static __be32 encode_string(struct xdr_stream *xdr, unsigned int len, const char *str)
570 {
571 	if (unlikely(xdr_stream_encode_opaque(xdr, str, len) < 0))
572 		return cpu_to_be32(NFS4ERR_RESOURCE);
573 	return 0;
574 }
575 
576 #define CB_SUPPORTED_ATTR0 (FATTR4_WORD0_CHANGE|FATTR4_WORD0_SIZE)
577 #define CB_SUPPORTED_ATTR1 (FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY)
578 static __be32 encode_attr_bitmap(struct xdr_stream *xdr, const uint32_t *bitmap, __be32 **savep)
579 {
580 	__be32 bm[2];
581 	__be32 *p;
582 
583 	bm[0] = htonl(bitmap[0] & CB_SUPPORTED_ATTR0);
584 	bm[1] = htonl(bitmap[1] & CB_SUPPORTED_ATTR1);
585 	if (bm[1] != 0) {
586 		p = xdr_reserve_space(xdr, 16);
587 		if (unlikely(p == NULL))
588 			return htonl(NFS4ERR_RESOURCE);
589 		*p++ = htonl(2);
590 		*p++ = bm[0];
591 		*p++ = bm[1];
592 	} else if (bm[0] != 0) {
593 		p = xdr_reserve_space(xdr, 12);
594 		if (unlikely(p == NULL))
595 			return htonl(NFS4ERR_RESOURCE);
596 		*p++ = htonl(1);
597 		*p++ = bm[0];
598 	} else {
599 		p = xdr_reserve_space(xdr, 8);
600 		if (unlikely(p == NULL))
601 			return htonl(NFS4ERR_RESOURCE);
602 		*p++ = htonl(0);
603 	}
604 	*savep = p;
605 	return 0;
606 }
607 
608 static __be32 encode_attr_change(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t change)
609 {
610 	__be32 *p;
611 
612 	if (!(bitmap[0] & FATTR4_WORD0_CHANGE))
613 		return 0;
614 	p = xdr_reserve_space(xdr, 8);
615 	if (unlikely(!p))
616 		return htonl(NFS4ERR_RESOURCE);
617 	p = xdr_encode_hyper(p, change);
618 	return 0;
619 }
620 
621 static __be32 encode_attr_size(struct xdr_stream *xdr, const uint32_t *bitmap, uint64_t size)
622 {
623 	__be32 *p;
624 
625 	if (!(bitmap[0] & FATTR4_WORD0_SIZE))
626 		return 0;
627 	p = xdr_reserve_space(xdr, 8);
628 	if (unlikely(!p))
629 		return htonl(NFS4ERR_RESOURCE);
630 	p = xdr_encode_hyper(p, size);
631 	return 0;
632 }
633 
634 static __be32 encode_attr_time(struct xdr_stream *xdr, const struct timespec *time)
635 {
636 	__be32 *p;
637 
638 	p = xdr_reserve_space(xdr, 12);
639 	if (unlikely(!p))
640 		return htonl(NFS4ERR_RESOURCE);
641 	p = xdr_encode_hyper(p, time->tv_sec);
642 	*p = htonl(time->tv_nsec);
643 	return 0;
644 }
645 
646 static __be32 encode_attr_ctime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
647 {
648 	if (!(bitmap[1] & FATTR4_WORD1_TIME_METADATA))
649 		return 0;
650 	return encode_attr_time(xdr,time);
651 }
652 
653 static __be32 encode_attr_mtime(struct xdr_stream *xdr, const uint32_t *bitmap, const struct timespec *time)
654 {
655 	if (!(bitmap[1] & FATTR4_WORD1_TIME_MODIFY))
656 		return 0;
657 	return encode_attr_time(xdr,time);
658 }
659 
660 static __be32 encode_compound_hdr_res(struct xdr_stream *xdr, struct cb_compound_hdr_res *hdr)
661 {
662 	__be32 status;
663 
664 	hdr->status = xdr_reserve_space(xdr, 4);
665 	if (unlikely(hdr->status == NULL))
666 		return htonl(NFS4ERR_RESOURCE);
667 	status = encode_string(xdr, hdr->taglen, hdr->tag);
668 	if (unlikely(status != 0))
669 		return status;
670 	hdr->nops = xdr_reserve_space(xdr, 4);
671 	if (unlikely(hdr->nops == NULL))
672 		return htonl(NFS4ERR_RESOURCE);
673 	return 0;
674 }
675 
676 static __be32 encode_op_hdr(struct xdr_stream *xdr, uint32_t op, __be32 res)
677 {
678 	__be32 *p;
679 
680 	p = xdr_reserve_space(xdr, 8);
681 	if (unlikely(p == NULL))
682 		return htonl(NFS4ERR_RESOURCE_HDR);
683 	*p++ = htonl(op);
684 	*p = res;
685 	return 0;
686 }
687 
688 static __be32 encode_getattr_res(struct svc_rqst *rqstp, struct xdr_stream *xdr, const struct cb_getattrres *res)
689 {
690 	__be32 *savep = NULL;
691 	__be32 status = res->status;
692 
693 	if (unlikely(status != 0))
694 		goto out;
695 	status = encode_attr_bitmap(xdr, res->bitmap, &savep);
696 	if (unlikely(status != 0))
697 		goto out;
698 	status = encode_attr_change(xdr, res->bitmap, res->change_attr);
699 	if (unlikely(status != 0))
700 		goto out;
701 	status = encode_attr_size(xdr, res->bitmap, res->size);
702 	if (unlikely(status != 0))
703 		goto out;
704 	status = encode_attr_ctime(xdr, res->bitmap, &res->ctime);
705 	if (unlikely(status != 0))
706 		goto out;
707 	status = encode_attr_mtime(xdr, res->bitmap, &res->mtime);
708 	*savep = htonl((unsigned int)((char *)xdr->p - (char *)(savep+1)));
709 out:
710 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
711 	return status;
712 }
713 
714 #if defined(CONFIG_NFS_V4_1)
715 
716 static __be32 encode_sessionid(struct xdr_stream *xdr,
717 				 const struct nfs4_sessionid *sid)
718 {
719 	__be32 *p;
720 
721 	p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
722 	if (unlikely(p == NULL))
723 		return htonl(NFS4ERR_RESOURCE);
724 
725 	memcpy(p, sid, NFS4_MAX_SESSIONID_LEN);
726 	return 0;
727 }
728 
729 static __be32 encode_cb_sequence_res(struct svc_rqst *rqstp,
730 				       struct xdr_stream *xdr,
731 				       const struct cb_sequenceres *res)
732 {
733 	__be32 *p;
734 	__be32 status = res->csr_status;
735 
736 	if (unlikely(status != 0))
737 		goto out;
738 
739 	status = encode_sessionid(xdr, &res->csr_sessionid);
740 	if (status)
741 		goto out;
742 
743 	p = xdr_reserve_space(xdr, 4 * sizeof(uint32_t));
744 	if (unlikely(p == NULL))
745 		return htonl(NFS4ERR_RESOURCE);
746 
747 	*p++ = htonl(res->csr_sequenceid);
748 	*p++ = htonl(res->csr_slotid);
749 	*p++ = htonl(res->csr_highestslotid);
750 	*p++ = htonl(res->csr_target_highestslotid);
751 out:
752 	dprintk("%s: exit with status = %d\n", __func__, ntohl(status));
753 	return status;
754 }
755 
756 static __be32
757 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
758 {
759 	if (op_nr == OP_CB_SEQUENCE) {
760 		if (nop != 0)
761 			return htonl(NFS4ERR_SEQUENCE_POS);
762 	} else {
763 		if (nop == 0)
764 			return htonl(NFS4ERR_OP_NOT_IN_SESSION);
765 	}
766 
767 	switch (op_nr) {
768 	case OP_CB_GETATTR:
769 	case OP_CB_RECALL:
770 	case OP_CB_SEQUENCE:
771 	case OP_CB_RECALL_ANY:
772 	case OP_CB_RECALL_SLOT:
773 	case OP_CB_LAYOUTRECALL:
774 	case OP_CB_NOTIFY_DEVICEID:
775 	case OP_CB_NOTIFY_LOCK:
776 		*op = &callback_ops[op_nr];
777 		break;
778 
779 	case OP_CB_NOTIFY:
780 	case OP_CB_PUSH_DELEG:
781 	case OP_CB_RECALLABLE_OBJ_AVAIL:
782 	case OP_CB_WANTS_CANCELLED:
783 		return htonl(NFS4ERR_NOTSUPP);
784 
785 	default:
786 		return htonl(NFS4ERR_OP_ILLEGAL);
787 	}
788 
789 	return htonl(NFS_OK);
790 }
791 
792 static void nfs4_callback_free_slot(struct nfs4_session *session,
793 		struct nfs4_slot *slot)
794 {
795 	struct nfs4_slot_table *tbl = &session->bc_slot_table;
796 
797 	spin_lock(&tbl->slot_tbl_lock);
798 	/*
799 	 * Let the state manager know callback processing done.
800 	 * A single slot, so highest used slotid is either 0 or -1
801 	 */
802 	nfs4_free_slot(tbl, slot);
803 	nfs4_slot_tbl_drain_complete(tbl);
804 	spin_unlock(&tbl->slot_tbl_lock);
805 }
806 
807 static void nfs4_cb_free_slot(struct cb_process_state *cps)
808 {
809 	if (cps->slot) {
810 		nfs4_callback_free_slot(cps->clp->cl_session, cps->slot);
811 		cps->slot = NULL;
812 	}
813 }
814 
815 #else /* CONFIG_NFS_V4_1 */
816 
817 static __be32
818 preprocess_nfs41_op(int nop, unsigned int op_nr, struct callback_op **op)
819 {
820 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
821 }
822 
823 static void nfs4_cb_free_slot(struct cb_process_state *cps)
824 {
825 }
826 #endif /* CONFIG_NFS_V4_1 */
827 
828 #ifdef CONFIG_NFS_V4_2
829 static __be32
830 preprocess_nfs42_op(int nop, unsigned int op_nr, struct callback_op **op)
831 {
832 	__be32 status = preprocess_nfs41_op(nop, op_nr, op);
833 	if (status != htonl(NFS4ERR_OP_ILLEGAL))
834 		return status;
835 
836 	if (op_nr == OP_CB_OFFLOAD)
837 		return htonl(NFS4ERR_NOTSUPP);
838 	return htonl(NFS4ERR_OP_ILLEGAL);
839 }
840 #else /* CONFIG_NFS_V4_2 */
841 static __be32
842 preprocess_nfs42_op(int nop, unsigned int op_nr, struct callback_op **op)
843 {
844 	return htonl(NFS4ERR_MINOR_VERS_MISMATCH);
845 }
846 #endif /* CONFIG_NFS_V4_2 */
847 
848 static __be32
849 preprocess_nfs4_op(unsigned int op_nr, struct callback_op **op)
850 {
851 	switch (op_nr) {
852 	case OP_CB_GETATTR:
853 	case OP_CB_RECALL:
854 		*op = &callback_ops[op_nr];
855 		break;
856 	default:
857 		return htonl(NFS4ERR_OP_ILLEGAL);
858 	}
859 
860 	return htonl(NFS_OK);
861 }
862 
863 static __be32 process_op(int nop, struct svc_rqst *rqstp,
864 		struct xdr_stream *xdr_in, void *argp,
865 		struct xdr_stream *xdr_out, void *resp,
866 		struct cb_process_state *cps)
867 {
868 	struct callback_op *op = &callback_ops[0];
869 	unsigned int op_nr;
870 	__be32 status;
871 	long maxlen;
872 	__be32 res;
873 
874 	dprintk("%s: start\n", __func__);
875 	status = decode_op_hdr(xdr_in, &op_nr);
876 	if (unlikely(status))
877 		return status;
878 
879 	dprintk("%s: minorversion=%d nop=%d op_nr=%u\n",
880 		__func__, cps->minorversion, nop, op_nr);
881 
882 	switch (cps->minorversion) {
883 	case 0:
884 		status = preprocess_nfs4_op(op_nr, &op);
885 		break;
886 	case 1:
887 		status = preprocess_nfs41_op(nop, op_nr, &op);
888 		break;
889 	case 2:
890 		status = preprocess_nfs42_op(nop, op_nr, &op);
891 		break;
892 	default:
893 		status = htonl(NFS4ERR_MINOR_VERS_MISMATCH);
894 	}
895 
896 	if (status == htonl(NFS4ERR_OP_ILLEGAL))
897 		op_nr = OP_CB_ILLEGAL;
898 	if (status)
899 		goto encode_hdr;
900 
901 	if (cps->drc_status) {
902 		status = cps->drc_status;
903 		goto encode_hdr;
904 	}
905 
906 	maxlen = xdr_out->end - xdr_out->p;
907 	if (maxlen > 0 && maxlen < PAGE_SIZE) {
908 		status = op->decode_args(rqstp, xdr_in, argp);
909 		if (likely(status == 0))
910 			status = op->process_op(argp, resp, cps);
911 	} else
912 		status = htonl(NFS4ERR_RESOURCE);
913 
914 encode_hdr:
915 	res = encode_op_hdr(xdr_out, op_nr, status);
916 	if (unlikely(res))
917 		return res;
918 	if (op->encode_res != NULL && status == 0)
919 		status = op->encode_res(rqstp, xdr_out, resp);
920 	dprintk("%s: done, status = %d\n", __func__, ntohl(status));
921 	return status;
922 }
923 
924 /*
925  * Decode, process and encode a COMPOUND
926  */
927 static __be32 nfs4_callback_compound(struct svc_rqst *rqstp, void *argp, void *resp)
928 {
929 	struct cb_compound_hdr_arg hdr_arg = { 0 };
930 	struct cb_compound_hdr_res hdr_res = { NULL };
931 	struct xdr_stream xdr_in, xdr_out;
932 	__be32 *p, status;
933 	struct cb_process_state cps = {
934 		.drc_status = 0,
935 		.clp = NULL,
936 		.net = SVC_NET(rqstp),
937 	};
938 	unsigned int nops = 0;
939 
940 	dprintk("%s: start\n", __func__);
941 
942 	xdr_init_decode(&xdr_in, &rqstp->rq_arg, rqstp->rq_arg.head[0].iov_base);
943 
944 	p = (__be32*)((char *)rqstp->rq_res.head[0].iov_base + rqstp->rq_res.head[0].iov_len);
945 	xdr_init_encode(&xdr_out, &rqstp->rq_res, p);
946 
947 	status = decode_compound_hdr_arg(&xdr_in, &hdr_arg);
948 	if (status == htonl(NFS4ERR_RESOURCE))
949 		return rpc_garbage_args;
950 
951 	if (hdr_arg.minorversion == 0) {
952 		cps.clp = nfs4_find_client_ident(SVC_NET(rqstp), hdr_arg.cb_ident);
953 		if (!cps.clp || !check_gss_callback_principal(cps.clp, rqstp))
954 			goto out_invalidcred;
955 	}
956 
957 	cps.minorversion = hdr_arg.minorversion;
958 	hdr_res.taglen = hdr_arg.taglen;
959 	hdr_res.tag = hdr_arg.tag;
960 	if (encode_compound_hdr_res(&xdr_out, &hdr_res) != 0)
961 		return rpc_system_err;
962 
963 	while (status == 0 && nops != hdr_arg.nops) {
964 		status = process_op(nops, rqstp, &xdr_in,
965 				    argp, &xdr_out, resp, &cps);
966 		nops++;
967 	}
968 
969 	/* Buffer overflow in decode_ops_hdr or encode_ops_hdr. Return
970 	* resource error in cb_compound status without returning op */
971 	if (unlikely(status == htonl(NFS4ERR_RESOURCE_HDR))) {
972 		status = htonl(NFS4ERR_RESOURCE);
973 		nops--;
974 	}
975 
976 	*hdr_res.status = status;
977 	*hdr_res.nops = htonl(nops);
978 	nfs4_cb_free_slot(&cps);
979 	nfs_put_client(cps.clp);
980 	dprintk("%s: done, status = %u\n", __func__, ntohl(status));
981 	return rpc_success;
982 
983 out_invalidcred:
984 	pr_warn_ratelimited("NFS: NFSv4 callback contains invalid cred\n");
985 	return rpc_autherr_badcred;
986 }
987 
988 /*
989  * Define NFS4 callback COMPOUND ops.
990  */
991 static struct callback_op callback_ops[] = {
992 	[0] = {
993 		.res_maxsize = CB_OP_HDR_RES_MAXSZ,
994 	},
995 	[OP_CB_GETATTR] = {
996 		.process_op = (callback_process_op_t)nfs4_callback_getattr,
997 		.decode_args = (callback_decode_arg_t)decode_getattr_args,
998 		.encode_res = (callback_encode_res_t)encode_getattr_res,
999 		.res_maxsize = CB_OP_GETATTR_RES_MAXSZ,
1000 	},
1001 	[OP_CB_RECALL] = {
1002 		.process_op = (callback_process_op_t)nfs4_callback_recall,
1003 		.decode_args = (callback_decode_arg_t)decode_recall_args,
1004 		.res_maxsize = CB_OP_RECALL_RES_MAXSZ,
1005 	},
1006 #if defined(CONFIG_NFS_V4_1)
1007 	[OP_CB_LAYOUTRECALL] = {
1008 		.process_op = (callback_process_op_t)nfs4_callback_layoutrecall,
1009 		.decode_args =
1010 			(callback_decode_arg_t)decode_layoutrecall_args,
1011 		.res_maxsize = CB_OP_LAYOUTRECALL_RES_MAXSZ,
1012 	},
1013 	[OP_CB_NOTIFY_DEVICEID] = {
1014 		.process_op = (callback_process_op_t)nfs4_callback_devicenotify,
1015 		.decode_args =
1016 			(callback_decode_arg_t)decode_devicenotify_args,
1017 		.res_maxsize = CB_OP_DEVICENOTIFY_RES_MAXSZ,
1018 	},
1019 	[OP_CB_SEQUENCE] = {
1020 		.process_op = (callback_process_op_t)nfs4_callback_sequence,
1021 		.decode_args = (callback_decode_arg_t)decode_cb_sequence_args,
1022 		.encode_res = (callback_encode_res_t)encode_cb_sequence_res,
1023 		.res_maxsize = CB_OP_SEQUENCE_RES_MAXSZ,
1024 	},
1025 	[OP_CB_RECALL_ANY] = {
1026 		.process_op = (callback_process_op_t)nfs4_callback_recallany,
1027 		.decode_args = (callback_decode_arg_t)decode_recallany_args,
1028 		.res_maxsize = CB_OP_RECALLANY_RES_MAXSZ,
1029 	},
1030 	[OP_CB_RECALL_SLOT] = {
1031 		.process_op = (callback_process_op_t)nfs4_callback_recallslot,
1032 		.decode_args = (callback_decode_arg_t)decode_recallslot_args,
1033 		.res_maxsize = CB_OP_RECALLSLOT_RES_MAXSZ,
1034 	},
1035 	[OP_CB_NOTIFY_LOCK] = {
1036 		.process_op = (callback_process_op_t)nfs4_callback_notify_lock,
1037 		.decode_args = (callback_decode_arg_t)decode_notify_lock_args,
1038 		.res_maxsize = CB_OP_NOTIFY_LOCK_RES_MAXSZ,
1039 	},
1040 #endif /* CONFIG_NFS_V4_1 */
1041 };
1042 
1043 /*
1044  * Define NFS4 callback procedures
1045  */
1046 static struct svc_procedure nfs4_callback_procedures1[] = {
1047 	[CB_NULL] = {
1048 		.pc_func = nfs4_callback_null,
1049 		.pc_decode = (kxdrproc_t)nfs4_decode_void,
1050 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
1051 		.pc_xdrressize = 1,
1052 	},
1053 	[CB_COMPOUND] = {
1054 		.pc_func = nfs4_callback_compound,
1055 		.pc_encode = (kxdrproc_t)nfs4_encode_void,
1056 		.pc_argsize = 256,
1057 		.pc_ressize = 256,
1058 		.pc_xdrressize = NFS4_CALLBACK_BUFSIZE,
1059 	}
1060 };
1061 
1062 struct svc_version nfs4_callback_version1 = {
1063 	.vs_vers = 1,
1064 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
1065 	.vs_proc = nfs4_callback_procedures1,
1066 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
1067 	.vs_dispatch = NULL,
1068 	.vs_hidden = true,
1069 	.vs_need_cong_ctrl = true,
1070 };
1071 
1072 struct svc_version nfs4_callback_version4 = {
1073 	.vs_vers = 4,
1074 	.vs_nproc = ARRAY_SIZE(nfs4_callback_procedures1),
1075 	.vs_proc = nfs4_callback_procedures1,
1076 	.vs_xdrsize = NFS4_CALLBACK_XDRSIZE,
1077 	.vs_dispatch = NULL,
1078 	.vs_hidden = true,
1079 	.vs_need_cong_ctrl = true,
1080 };
1081