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1 /*
2  *  Copyright (c) 2001 The Regents of the University of Michigan.
3  *  All rights reserved.
4  *
5  *  Kendrick Smith <kmsmith@umich.edu>
6  *  Andy Adamson <andros@umich.edu>
7  *
8  *  Redistribution and use in source and binary forms, with or without
9  *  modification, are permitted provided that the following conditions
10  *  are met:
11  *
12  *  1. Redistributions of source code must retain the above copyright
13  *     notice, this list of conditions and the following disclaimer.
14  *  2. Redistributions in binary form must reproduce the above copyright
15  *     notice, this list of conditions and the following disclaimer in the
16  *     documentation and/or other materials provided with the distribution.
17  *  3. Neither the name of the University nor the names of its
18  *     contributors may be used to endorse or promote products derived
19  *     from this software without specific prior written permission.
20  *
21  *  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
22  *  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23  *  MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
24  *  DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25  *  FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
26  *  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
27  *  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
28  *  BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
29  *  LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
30  *  NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
31  *  SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
32  */
33 
34 #include <linux/sunrpc/clnt.h>
35 #include <linux/sunrpc/svc_xprt.h>
36 #include <linux/slab.h>
37 #include "nfsd.h"
38 #include "state.h"
39 #include "netns.h"
40 #include "xdr4cb.h"
41 
42 #define NFSDDBG_FACILITY                NFSDDBG_PROC
43 
44 static void nfsd4_mark_cb_fault(struct nfs4_client *, int reason);
45 
46 #define NFSPROC4_CB_NULL 0
47 #define NFSPROC4_CB_COMPOUND 1
48 
49 /* Index of predefined Linux callback client operations */
50 
51 enum {
52 	NFSPROC4_CLNT_CB_NULL = 0,
53 	NFSPROC4_CLNT_CB_RECALL,
54 	NFSPROC4_CLNT_CB_SEQUENCE,
55 };
56 
57 struct nfs4_cb_compound_hdr {
58 	/* args */
59 	u32		ident;	/* minorversion 0 only */
60 	u32		nops;
61 	__be32		*nops_p;
62 	u32		minorversion;
63 	/* res */
64 	int		status;
65 };
66 
67 /*
68  * Handle decode buffer overflows out-of-line.
69  */
print_overflow_msg(const char * func,const struct xdr_stream * xdr)70 static void print_overflow_msg(const char *func, const struct xdr_stream *xdr)
71 {
72 	dprintk("NFS: %s prematurely hit the end of our receive buffer. "
73 		"Remaining buffer length is %tu words.\n",
74 		func, xdr->end - xdr->p);
75 }
76 
xdr_encode_empty_array(__be32 * p)77 static __be32 *xdr_encode_empty_array(__be32 *p)
78 {
79 	*p++ = xdr_zero;
80 	return p;
81 }
82 
83 /*
84  * Encode/decode NFSv4 CB basic data types
85  *
86  * Basic NFSv4 callback data types are defined in section 15 of RFC
87  * 3530: "Network File System (NFS) version 4 Protocol" and section
88  * 20 of RFC 5661: "Network File System (NFS) Version 4 Minor Version
89  * 1 Protocol"
90  */
91 
92 /*
93  *	nfs_cb_opnum4
94  *
95  *	enum nfs_cb_opnum4 {
96  *		OP_CB_GETATTR		= 3,
97  *		  ...
98  *	};
99  */
100 enum nfs_cb_opnum4 {
101 	OP_CB_GETATTR			= 3,
102 	OP_CB_RECALL			= 4,
103 	OP_CB_LAYOUTRECALL		= 5,
104 	OP_CB_NOTIFY			= 6,
105 	OP_CB_PUSH_DELEG		= 7,
106 	OP_CB_RECALL_ANY		= 8,
107 	OP_CB_RECALLABLE_OBJ_AVAIL	= 9,
108 	OP_CB_RECALL_SLOT		= 10,
109 	OP_CB_SEQUENCE			= 11,
110 	OP_CB_WANTS_CANCELLED		= 12,
111 	OP_CB_NOTIFY_LOCK		= 13,
112 	OP_CB_NOTIFY_DEVICEID		= 14,
113 	OP_CB_ILLEGAL			= 10044
114 };
115 
encode_nfs_cb_opnum4(struct xdr_stream * xdr,enum nfs_cb_opnum4 op)116 static void encode_nfs_cb_opnum4(struct xdr_stream *xdr, enum nfs_cb_opnum4 op)
117 {
118 	__be32 *p;
119 
120 	p = xdr_reserve_space(xdr, 4);
121 	*p = cpu_to_be32(op);
122 }
123 
124 /*
125  * nfs_fh4
126  *
127  *	typedef opaque nfs_fh4<NFS4_FHSIZE>;
128  */
encode_nfs_fh4(struct xdr_stream * xdr,const struct knfsd_fh * fh)129 static void encode_nfs_fh4(struct xdr_stream *xdr, const struct knfsd_fh *fh)
130 {
131 	u32 length = fh->fh_size;
132 	__be32 *p;
133 
134 	BUG_ON(length > NFS4_FHSIZE);
135 	p = xdr_reserve_space(xdr, 4 + length);
136 	xdr_encode_opaque(p, &fh->fh_base, length);
137 }
138 
139 /*
140  * stateid4
141  *
142  *	struct stateid4 {
143  *		uint32_t	seqid;
144  *		opaque		other[12];
145  *	};
146  */
encode_stateid4(struct xdr_stream * xdr,const stateid_t * sid)147 static void encode_stateid4(struct xdr_stream *xdr, const stateid_t *sid)
148 {
149 	__be32 *p;
150 
151 	p = xdr_reserve_space(xdr, NFS4_STATEID_SIZE);
152 	*p++ = cpu_to_be32(sid->si_generation);
153 	xdr_encode_opaque_fixed(p, &sid->si_opaque, NFS4_STATEID_OTHER_SIZE);
154 }
155 
156 /*
157  * sessionid4
158  *
159  *	typedef opaque sessionid4[NFS4_SESSIONID_SIZE];
160  */
encode_sessionid4(struct xdr_stream * xdr,const struct nfsd4_session * session)161 static void encode_sessionid4(struct xdr_stream *xdr,
162 			      const struct nfsd4_session *session)
163 {
164 	__be32 *p;
165 
166 	p = xdr_reserve_space(xdr, NFS4_MAX_SESSIONID_LEN);
167 	xdr_encode_opaque_fixed(p, session->se_sessionid.data,
168 					NFS4_MAX_SESSIONID_LEN);
169 }
170 
171 /*
172  * nfsstat4
173  */
174 static const struct {
175 	int stat;
176 	int errno;
177 } nfs_cb_errtbl[] = {
178 	{ NFS4_OK,		0		},
179 	{ NFS4ERR_PERM,		-EPERM		},
180 	{ NFS4ERR_NOENT,	-ENOENT		},
181 	{ NFS4ERR_IO,		-EIO		},
182 	{ NFS4ERR_NXIO,		-ENXIO		},
183 	{ NFS4ERR_ACCESS,	-EACCES		},
184 	{ NFS4ERR_EXIST,	-EEXIST		},
185 	{ NFS4ERR_XDEV,		-EXDEV		},
186 	{ NFS4ERR_NOTDIR,	-ENOTDIR	},
187 	{ NFS4ERR_ISDIR,	-EISDIR		},
188 	{ NFS4ERR_INVAL,	-EINVAL		},
189 	{ NFS4ERR_FBIG,		-EFBIG		},
190 	{ NFS4ERR_NOSPC,	-ENOSPC		},
191 	{ NFS4ERR_ROFS,		-EROFS		},
192 	{ NFS4ERR_MLINK,	-EMLINK		},
193 	{ NFS4ERR_NAMETOOLONG,	-ENAMETOOLONG	},
194 	{ NFS4ERR_NOTEMPTY,	-ENOTEMPTY	},
195 	{ NFS4ERR_DQUOT,	-EDQUOT		},
196 	{ NFS4ERR_STALE,	-ESTALE		},
197 	{ NFS4ERR_BADHANDLE,	-EBADHANDLE	},
198 	{ NFS4ERR_BAD_COOKIE,	-EBADCOOKIE	},
199 	{ NFS4ERR_NOTSUPP,	-ENOTSUPP	},
200 	{ NFS4ERR_TOOSMALL,	-ETOOSMALL	},
201 	{ NFS4ERR_SERVERFAULT,	-ESERVERFAULT	},
202 	{ NFS4ERR_BADTYPE,	-EBADTYPE	},
203 	{ NFS4ERR_LOCKED,	-EAGAIN		},
204 	{ NFS4ERR_RESOURCE,	-EREMOTEIO	},
205 	{ NFS4ERR_SYMLINK,	-ELOOP		},
206 	{ NFS4ERR_OP_ILLEGAL,	-EOPNOTSUPP	},
207 	{ NFS4ERR_DEADLOCK,	-EDEADLK	},
208 	{ -1,			-EIO		}
209 };
210 
211 /*
212  * If we cannot translate the error, the recovery routines should
213  * handle it.
214  *
215  * Note: remaining NFSv4 error codes have values > 10000, so should
216  * not conflict with native Linux error codes.
217  */
nfs_cb_stat_to_errno(int status)218 static int nfs_cb_stat_to_errno(int status)
219 {
220 	int i;
221 
222 	for (i = 0; nfs_cb_errtbl[i].stat != -1; i++) {
223 		if (nfs_cb_errtbl[i].stat == status)
224 			return nfs_cb_errtbl[i].errno;
225 	}
226 
227 	dprintk("NFSD: Unrecognized NFS CB status value: %u\n", status);
228 	return -status;
229 }
230 
decode_cb_op_status(struct xdr_stream * xdr,enum nfs_opnum4 expected,enum nfsstat4 * status)231 static int decode_cb_op_status(struct xdr_stream *xdr, enum nfs_opnum4 expected,
232 			       enum nfsstat4 *status)
233 {
234 	__be32 *p;
235 	u32 op;
236 
237 	p = xdr_inline_decode(xdr, 4 + 4);
238 	if (unlikely(p == NULL))
239 		goto out_overflow;
240 	op = be32_to_cpup(p++);
241 	if (unlikely(op != expected))
242 		goto out_unexpected;
243 	*status = be32_to_cpup(p);
244 	return 0;
245 out_overflow:
246 	print_overflow_msg(__func__, xdr);
247 	return -EIO;
248 out_unexpected:
249 	dprintk("NFSD: Callback server returned operation %d but "
250 		"we issued a request for %d\n", op, expected);
251 	return -EIO;
252 }
253 
254 /*
255  * CB_COMPOUND4args
256  *
257  *	struct CB_COMPOUND4args {
258  *		utf8str_cs	tag;
259  *		uint32_t	minorversion;
260  *		uint32_t	callback_ident;
261  *		nfs_cb_argop4	argarray<>;
262  *	};
263 */
encode_cb_compound4args(struct xdr_stream * xdr,struct nfs4_cb_compound_hdr * hdr)264 static void encode_cb_compound4args(struct xdr_stream *xdr,
265 				    struct nfs4_cb_compound_hdr *hdr)
266 {
267 	__be32 * p;
268 
269 	p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4);
270 	p = xdr_encode_empty_array(p);		/* empty tag */
271 	*p++ = cpu_to_be32(hdr->minorversion);
272 	*p++ = cpu_to_be32(hdr->ident);
273 
274 	hdr->nops_p = p;
275 	*p = cpu_to_be32(hdr->nops);		/* argarray element count */
276 }
277 
278 /*
279  * Update argarray element count
280  */
encode_cb_nops(struct nfs4_cb_compound_hdr * hdr)281 static void encode_cb_nops(struct nfs4_cb_compound_hdr *hdr)
282 {
283 	BUG_ON(hdr->nops > NFS4_MAX_BACK_CHANNEL_OPS);
284 	*hdr->nops_p = cpu_to_be32(hdr->nops);
285 }
286 
287 /*
288  * CB_COMPOUND4res
289  *
290  *	struct CB_COMPOUND4res {
291  *		nfsstat4	status;
292  *		utf8str_cs	tag;
293  *		nfs_cb_resop4	resarray<>;
294  *	};
295  */
decode_cb_compound4res(struct xdr_stream * xdr,struct nfs4_cb_compound_hdr * hdr)296 static int decode_cb_compound4res(struct xdr_stream *xdr,
297 				  struct nfs4_cb_compound_hdr *hdr)
298 {
299 	u32 length;
300 	__be32 *p;
301 
302 	p = xdr_inline_decode(xdr, 4 + 4);
303 	if (unlikely(p == NULL))
304 		goto out_overflow;
305 	hdr->status = be32_to_cpup(p++);
306 	/* Ignore the tag */
307 	length = be32_to_cpup(p++);
308 	p = xdr_inline_decode(xdr, length + 4);
309 	if (unlikely(p == NULL))
310 		goto out_overflow;
311 	hdr->nops = be32_to_cpup(p);
312 	return 0;
313 out_overflow:
314 	print_overflow_msg(__func__, xdr);
315 	return -EIO;
316 }
317 
318 /*
319  * CB_RECALL4args
320  *
321  *	struct CB_RECALL4args {
322  *		stateid4	stateid;
323  *		bool		truncate;
324  *		nfs_fh4		fh;
325  *	};
326  */
encode_cb_recall4args(struct xdr_stream * xdr,const struct nfs4_delegation * dp,struct nfs4_cb_compound_hdr * hdr)327 static void encode_cb_recall4args(struct xdr_stream *xdr,
328 				  const struct nfs4_delegation *dp,
329 				  struct nfs4_cb_compound_hdr *hdr)
330 {
331 	__be32 *p;
332 
333 	encode_nfs_cb_opnum4(xdr, OP_CB_RECALL);
334 	encode_stateid4(xdr, &dp->dl_stid.sc_stateid);
335 
336 	p = xdr_reserve_space(xdr, 4);
337 	*p++ = xdr_zero;			/* truncate */
338 
339 	encode_nfs_fh4(xdr, &dp->dl_fh);
340 
341 	hdr->nops++;
342 }
343 
344 /*
345  * CB_SEQUENCE4args
346  *
347  *	struct CB_SEQUENCE4args {
348  *		sessionid4		csa_sessionid;
349  *		sequenceid4		csa_sequenceid;
350  *		slotid4			csa_slotid;
351  *		slotid4			csa_highest_slotid;
352  *		bool			csa_cachethis;
353  *		referring_call_list4	csa_referring_call_lists<>;
354  *	};
355  */
encode_cb_sequence4args(struct xdr_stream * xdr,const struct nfsd4_callback * cb,struct nfs4_cb_compound_hdr * hdr)356 static void encode_cb_sequence4args(struct xdr_stream *xdr,
357 				    const struct nfsd4_callback *cb,
358 				    struct nfs4_cb_compound_hdr *hdr)
359 {
360 	struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
361 	__be32 *p;
362 
363 	if (hdr->minorversion == 0)
364 		return;
365 
366 	encode_nfs_cb_opnum4(xdr, OP_CB_SEQUENCE);
367 	encode_sessionid4(xdr, session);
368 
369 	p = xdr_reserve_space(xdr, 4 + 4 + 4 + 4 + 4);
370 	*p++ = cpu_to_be32(session->se_cb_seq_nr);	/* csa_sequenceid */
371 	*p++ = xdr_zero;			/* csa_slotid */
372 	*p++ = xdr_zero;			/* csa_highest_slotid */
373 	*p++ = xdr_zero;			/* csa_cachethis */
374 	xdr_encode_empty_array(p);		/* csa_referring_call_lists */
375 
376 	hdr->nops++;
377 }
378 
379 /*
380  * CB_SEQUENCE4resok
381  *
382  *	struct CB_SEQUENCE4resok {
383  *		sessionid4	csr_sessionid;
384  *		sequenceid4	csr_sequenceid;
385  *		slotid4		csr_slotid;
386  *		slotid4		csr_highest_slotid;
387  *		slotid4		csr_target_highest_slotid;
388  *	};
389  *
390  *	union CB_SEQUENCE4res switch (nfsstat4 csr_status) {
391  *	case NFS4_OK:
392  *		CB_SEQUENCE4resok	csr_resok4;
393  *	default:
394  *		void;
395  *	};
396  *
397  * Our current back channel implmentation supports a single backchannel
398  * with a single slot.
399  */
decode_cb_sequence4resok(struct xdr_stream * xdr,struct nfsd4_callback * cb)400 static int decode_cb_sequence4resok(struct xdr_stream *xdr,
401 				    struct nfsd4_callback *cb)
402 {
403 	struct nfsd4_session *session = cb->cb_clp->cl_cb_session;
404 	struct nfs4_sessionid id;
405 	int status;
406 	__be32 *p;
407 	u32 dummy;
408 
409 	status = -ESERVERFAULT;
410 
411 	/*
412 	 * If the server returns different values for sessionID, slotID or
413 	 * sequence number, the server is looney tunes.
414 	 */
415 	p = xdr_inline_decode(xdr, NFS4_MAX_SESSIONID_LEN + 4 + 4 + 4 + 4);
416 	if (unlikely(p == NULL))
417 		goto out_overflow;
418 	memcpy(id.data, p, NFS4_MAX_SESSIONID_LEN);
419 	if (memcmp(id.data, session->se_sessionid.data,
420 					NFS4_MAX_SESSIONID_LEN) != 0) {
421 		dprintk("NFS: %s Invalid session id\n", __func__);
422 		goto out;
423 	}
424 	p += XDR_QUADLEN(NFS4_MAX_SESSIONID_LEN);
425 
426 	dummy = be32_to_cpup(p++);
427 	if (dummy != session->se_cb_seq_nr) {
428 		dprintk("NFS: %s Invalid sequence number\n", __func__);
429 		goto out;
430 	}
431 
432 	dummy = be32_to_cpup(p++);
433 	if (dummy != 0) {
434 		dprintk("NFS: %s Invalid slotid\n", __func__);
435 		goto out;
436 	}
437 
438 	/*
439 	 * FIXME: process highest slotid and target highest slotid
440 	 */
441 	status = 0;
442 out:
443 	if (status)
444 		nfsd4_mark_cb_fault(cb->cb_clp, status);
445 	return status;
446 out_overflow:
447 	print_overflow_msg(__func__, xdr);
448 	return -EIO;
449 }
450 
decode_cb_sequence4res(struct xdr_stream * xdr,struct nfsd4_callback * cb)451 static int decode_cb_sequence4res(struct xdr_stream *xdr,
452 				  struct nfsd4_callback *cb)
453 {
454 	enum nfsstat4 nfserr;
455 	int status;
456 
457 	if (cb->cb_minorversion == 0)
458 		return 0;
459 
460 	status = decode_cb_op_status(xdr, OP_CB_SEQUENCE, &nfserr);
461 	if (unlikely(status))
462 		goto out;
463 	if (unlikely(nfserr != NFS4_OK))
464 		goto out_default;
465 	status = decode_cb_sequence4resok(xdr, cb);
466 out:
467 	return status;
468 out_default:
469 	return nfs_cb_stat_to_errno(nfserr);
470 }
471 
472 /*
473  * NFSv4.0 and NFSv4.1 XDR encode functions
474  *
475  * NFSv4.0 callback argument types are defined in section 15 of RFC
476  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
477  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
478  * Protocol".
479  */
480 
481 /*
482  * NB: Without this zero space reservation, callbacks over krb5p fail
483  */
nfs4_xdr_enc_cb_null(struct rpc_rqst * req,struct xdr_stream * xdr,void * __unused)484 static void nfs4_xdr_enc_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
485 				 void *__unused)
486 {
487 	xdr_reserve_space(xdr, 0);
488 }
489 
490 /*
491  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
492  */
nfs4_xdr_enc_cb_recall(struct rpc_rqst * req,struct xdr_stream * xdr,const struct nfsd4_callback * cb)493 static void nfs4_xdr_enc_cb_recall(struct rpc_rqst *req, struct xdr_stream *xdr,
494 				   const struct nfsd4_callback *cb)
495 {
496 	const struct nfs4_delegation *args = cb->cb_op;
497 	struct nfs4_cb_compound_hdr hdr = {
498 		.ident = cb->cb_clp->cl_cb_ident,
499 		.minorversion = cb->cb_minorversion,
500 	};
501 
502 	encode_cb_compound4args(xdr, &hdr);
503 	encode_cb_sequence4args(xdr, cb, &hdr);
504 	encode_cb_recall4args(xdr, args, &hdr);
505 	encode_cb_nops(&hdr);
506 }
507 
508 
509 /*
510  * NFSv4.0 and NFSv4.1 XDR decode functions
511  *
512  * NFSv4.0 callback result types are defined in section 15 of RFC
513  * 3530: "Network File System (NFS) version 4 Protocol" and section 20
514  * of RFC 5661:  "Network File System (NFS) Version 4 Minor Version 1
515  * Protocol".
516  */
517 
nfs4_xdr_dec_cb_null(struct rpc_rqst * req,struct xdr_stream * xdr,void * __unused)518 static int nfs4_xdr_dec_cb_null(struct rpc_rqst *req, struct xdr_stream *xdr,
519 				void *__unused)
520 {
521 	return 0;
522 }
523 
524 /*
525  * 20.2. Operation 4: CB_RECALL - Recall a Delegation
526  */
nfs4_xdr_dec_cb_recall(struct rpc_rqst * rqstp,struct xdr_stream * xdr,struct nfsd4_callback * cb)527 static int nfs4_xdr_dec_cb_recall(struct rpc_rqst *rqstp,
528 				  struct xdr_stream *xdr,
529 				  struct nfsd4_callback *cb)
530 {
531 	struct nfs4_cb_compound_hdr hdr;
532 	enum nfsstat4 nfserr;
533 	int status;
534 
535 	status = decode_cb_compound4res(xdr, &hdr);
536 	if (unlikely(status))
537 		goto out;
538 
539 	if (cb != NULL) {
540 		status = decode_cb_sequence4res(xdr, cb);
541 		if (unlikely(status))
542 			goto out;
543 	}
544 
545 	status = decode_cb_op_status(xdr, OP_CB_RECALL, &nfserr);
546 	if (unlikely(status))
547 		goto out;
548 	if (unlikely(nfserr != NFS4_OK))
549 		status = nfs_cb_stat_to_errno(nfserr);
550 out:
551 	return status;
552 }
553 
554 /*
555  * RPC procedure tables
556  */
557 #define PROC(proc, call, argtype, restype)				\
558 [NFSPROC4_CLNT_##proc] = {						\
559 	.p_proc    = NFSPROC4_CB_##call,				\
560 	.p_encode  = (kxdreproc_t)nfs4_xdr_enc_##argtype,		\
561 	.p_decode  = (kxdrdproc_t)nfs4_xdr_dec_##restype,		\
562 	.p_arglen  = NFS4_enc_##argtype##_sz,				\
563 	.p_replen  = NFS4_dec_##restype##_sz,				\
564 	.p_statidx = NFSPROC4_CB_##call,				\
565 	.p_name    = #proc,						\
566 }
567 
568 static struct rpc_procinfo nfs4_cb_procedures[] = {
569 	PROC(CB_NULL,	NULL,		cb_null,	cb_null),
570 	PROC(CB_RECALL,	COMPOUND,	cb_recall,	cb_recall),
571 };
572 
573 static struct rpc_version nfs_cb_version4 = {
574 /*
575  * Note on the callback rpc program version number: despite language in rfc
576  * 5661 section 18.36.3 requiring servers to use 4 in this field, the
577  * official xdr descriptions for both 4.0 and 4.1 specify version 1, and
578  * in practice that appears to be what implementations use.  The section
579  * 18.36.3 language is expected to be fixed in an erratum.
580  */
581 	.number			= 1,
582 	.nrprocs		= ARRAY_SIZE(nfs4_cb_procedures),
583 	.procs			= nfs4_cb_procedures
584 };
585 
586 static const struct rpc_version *nfs_cb_version[] = {
587 	&nfs_cb_version4,
588 };
589 
590 static const struct rpc_program cb_program;
591 
592 static struct rpc_stat cb_stats = {
593 	.program		= &cb_program
594 };
595 
596 #define NFS4_CALLBACK 0x40000000
597 static const struct rpc_program cb_program = {
598 	.name			= "nfs4_cb",
599 	.number			= NFS4_CALLBACK,
600 	.nrvers			= ARRAY_SIZE(nfs_cb_version),
601 	.version		= nfs_cb_version,
602 	.stats			= &cb_stats,
603 	.pipe_dir_name		= "nfsd4_cb",
604 };
605 
max_cb_time(struct net * net)606 static int max_cb_time(struct net *net)
607 {
608 	struct nfsd_net *nn = net_generic(net, nfsd_net_id);
609 	return max(nn->nfsd4_lease/10, (time_t)1) * HZ;
610 }
611 
612 static struct rpc_cred *callback_cred;
613 
set_callback_cred(void)614 int set_callback_cred(void)
615 {
616 	if (callback_cred)
617 		return 0;
618 	callback_cred = rpc_lookup_machine_cred("nfs");
619 	if (!callback_cred)
620 		return -ENOMEM;
621 	return 0;
622 }
623 
get_backchannel_cred(struct nfs4_client * clp,struct rpc_clnt * client,struct nfsd4_session * ses)624 static struct rpc_cred *get_backchannel_cred(struct nfs4_client *clp, struct rpc_clnt *client, struct nfsd4_session *ses)
625 {
626 	if (clp->cl_minorversion == 0) {
627 		return get_rpccred(callback_cred);
628 	} else {
629 		struct rpc_auth *auth = client->cl_auth;
630 		struct auth_cred acred = {};
631 
632 		acred.uid = ses->se_cb_sec.uid;
633 		acred.gid = ses->se_cb_sec.gid;
634 		return auth->au_ops->lookup_cred(client->cl_auth, &acred, 0);
635 	}
636 }
637 
setup_callback_client(struct nfs4_client * clp,struct nfs4_cb_conn * conn,struct nfsd4_session * ses)638 static int setup_callback_client(struct nfs4_client *clp, struct nfs4_cb_conn *conn, struct nfsd4_session *ses)
639 {
640 	struct rpc_timeout	timeparms = {
641 		.to_initval	= max_cb_time(clp->net),
642 		.to_retries	= 0,
643 	};
644 	struct rpc_create_args args = {
645 		.net		= clp->net,
646 		.address	= (struct sockaddr *) &conn->cb_addr,
647 		.addrsize	= conn->cb_addrlen,
648 		.saddress	= (struct sockaddr *) &conn->cb_saddr,
649 		.timeout	= &timeparms,
650 		.program	= &cb_program,
651 		.version	= 0,
652 		.flags		= (RPC_CLNT_CREATE_NOPING | RPC_CLNT_CREATE_QUIET),
653 	};
654 	struct rpc_clnt *client;
655 	struct rpc_cred *cred;
656 
657 	if (clp->cl_minorversion == 0) {
658 		if (!clp->cl_cred.cr_principal &&
659 				(clp->cl_cred.cr_flavor >= RPC_AUTH_GSS_KRB5))
660 			return -EINVAL;
661 		args.client_name = clp->cl_cred.cr_principal;
662 		args.prognumber	= conn->cb_prog,
663 		args.protocol = XPRT_TRANSPORT_TCP;
664 		args.authflavor = clp->cl_cred.cr_flavor;
665 		clp->cl_cb_ident = conn->cb_ident;
666 	} else {
667 		if (!conn->cb_xprt)
668 			return -EINVAL;
669 		clp->cl_cb_conn.cb_xprt = conn->cb_xprt;
670 		clp->cl_cb_session = ses;
671 		args.bc_xprt = conn->cb_xprt;
672 		args.prognumber = clp->cl_cb_session->se_cb_prog;
673 		args.protocol = XPRT_TRANSPORT_BC_TCP;
674 		args.authflavor = ses->se_cb_sec.flavor;
675 	}
676 	/* Create RPC client */
677 	client = rpc_create(&args);
678 	if (IS_ERR(client)) {
679 		dprintk("NFSD: couldn't create callback client: %ld\n",
680 			PTR_ERR(client));
681 		return PTR_ERR(client);
682 	}
683 	cred = get_backchannel_cred(clp, client, ses);
684 	if (IS_ERR(cred)) {
685 		rpc_shutdown_client(client);
686 		return PTR_ERR(cred);
687 	}
688 	clp->cl_cb_client = client;
689 	clp->cl_cb_cred = cred;
690 	return 0;
691 }
692 
warn_no_callback_path(struct nfs4_client * clp,int reason)693 static void warn_no_callback_path(struct nfs4_client *clp, int reason)
694 {
695 	dprintk("NFSD: warning: no callback path to client %.*s: error %d\n",
696 		(int)clp->cl_name.len, clp->cl_name.data, reason);
697 }
698 
nfsd4_mark_cb_down(struct nfs4_client * clp,int reason)699 static void nfsd4_mark_cb_down(struct nfs4_client *clp, int reason)
700 {
701 	clp->cl_cb_state = NFSD4_CB_DOWN;
702 	warn_no_callback_path(clp, reason);
703 }
704 
nfsd4_mark_cb_fault(struct nfs4_client * clp,int reason)705 static void nfsd4_mark_cb_fault(struct nfs4_client *clp, int reason)
706 {
707 	clp->cl_cb_state = NFSD4_CB_FAULT;
708 	warn_no_callback_path(clp, reason);
709 }
710 
nfsd4_cb_probe_done(struct rpc_task * task,void * calldata)711 static void nfsd4_cb_probe_done(struct rpc_task *task, void *calldata)
712 {
713 	struct nfs4_client *clp = container_of(calldata, struct nfs4_client, cl_cb_null);
714 
715 	if (task->tk_status)
716 		nfsd4_mark_cb_down(clp, task->tk_status);
717 	else
718 		clp->cl_cb_state = NFSD4_CB_UP;
719 }
720 
721 static const struct rpc_call_ops nfsd4_cb_probe_ops = {
722 	/* XXX: release method to ensure we set the cb channel down if
723 	 * necessary on early failure? */
724 	.rpc_call_done = nfsd4_cb_probe_done,
725 };
726 
727 static struct workqueue_struct *callback_wq;
728 
run_nfsd4_cb(struct nfsd4_callback * cb)729 static void run_nfsd4_cb(struct nfsd4_callback *cb)
730 {
731 	queue_work(callback_wq, &cb->cb_work);
732 }
733 
do_probe_callback(struct nfs4_client * clp)734 static void do_probe_callback(struct nfs4_client *clp)
735 {
736 	struct nfsd4_callback *cb = &clp->cl_cb_null;
737 
738 	cb->cb_op = NULL;
739 	cb->cb_clp = clp;
740 
741 	cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_NULL];
742 	cb->cb_msg.rpc_argp = NULL;
743 	cb->cb_msg.rpc_resp = NULL;
744 
745 	cb->cb_ops = &nfsd4_cb_probe_ops;
746 
747 	run_nfsd4_cb(cb);
748 }
749 
750 /*
751  * Poke the callback thread to process any updates to the callback
752  * parameters, and send a null probe.
753  */
nfsd4_probe_callback(struct nfs4_client * clp)754 void nfsd4_probe_callback(struct nfs4_client *clp)
755 {
756 	clp->cl_cb_state = NFSD4_CB_UNKNOWN;
757 	set_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
758 	do_probe_callback(clp);
759 }
760 
nfsd4_probe_callback_sync(struct nfs4_client * clp)761 void nfsd4_probe_callback_sync(struct nfs4_client *clp)
762 {
763 	nfsd4_probe_callback(clp);
764 	flush_workqueue(callback_wq);
765 }
766 
nfsd4_change_callback(struct nfs4_client * clp,struct nfs4_cb_conn * conn)767 void nfsd4_change_callback(struct nfs4_client *clp, struct nfs4_cb_conn *conn)
768 {
769 	clp->cl_cb_state = NFSD4_CB_UNKNOWN;
770 	spin_lock(&clp->cl_lock);
771 	memcpy(&clp->cl_cb_conn, conn, sizeof(struct nfs4_cb_conn));
772 	spin_unlock(&clp->cl_lock);
773 }
774 
775 /*
776  * There's currently a single callback channel slot.
777  * If the slot is available, then mark it busy.  Otherwise, set the
778  * thread for sleeping on the callback RPC wait queue.
779  */
nfsd41_cb_get_slot(struct nfs4_client * clp,struct rpc_task * task)780 static bool nfsd41_cb_get_slot(struct nfs4_client *clp, struct rpc_task *task)
781 {
782 	if (test_and_set_bit(0, &clp->cl_cb_slot_busy) != 0) {
783 		rpc_sleep_on(&clp->cl_cb_waitq, task, NULL);
784 		dprintk("%s slot is busy\n", __func__);
785 		return false;
786 	}
787 	return true;
788 }
789 
790 /*
791  * TODO: cb_sequence should support referring call lists, cachethis, multiple
792  * slots, and mark callback channel down on communication errors.
793  */
nfsd4_cb_prepare(struct rpc_task * task,void * calldata)794 static void nfsd4_cb_prepare(struct rpc_task *task, void *calldata)
795 {
796 	struct nfsd4_callback *cb = calldata;
797 	struct nfs4_client *clp = cb->cb_clp;
798 	u32 minorversion = clp->cl_minorversion;
799 
800 	cb->cb_minorversion = minorversion;
801 	if (minorversion) {
802 		if (!nfsd41_cb_get_slot(clp, task))
803 			return;
804 	}
805 	spin_lock(&clp->cl_lock);
806 	if (list_empty(&cb->cb_per_client)) {
807 		/* This is the first call, not a restart */
808 		cb->cb_done = false;
809 		list_add(&cb->cb_per_client, &clp->cl_callbacks);
810 	}
811 	spin_unlock(&clp->cl_lock);
812 	rpc_call_start(task);
813 }
814 
nfsd4_cb_done(struct rpc_task * task,void * calldata)815 static void nfsd4_cb_done(struct rpc_task *task, void *calldata)
816 {
817 	struct nfsd4_callback *cb = calldata;
818 	struct nfs4_client *clp = cb->cb_clp;
819 
820 	dprintk("%s: minorversion=%d\n", __func__,
821 		clp->cl_minorversion);
822 
823 	if (clp->cl_minorversion) {
824 		/* No need for lock, access serialized in nfsd4_cb_prepare */
825 		++clp->cl_cb_session->se_cb_seq_nr;
826 		clear_bit(0, &clp->cl_cb_slot_busy);
827 		rpc_wake_up_next(&clp->cl_cb_waitq);
828 		dprintk("%s: freed slot, new seqid=%d\n", __func__,
829 			clp->cl_cb_session->se_cb_seq_nr);
830 
831 		/* We're done looking into the sequence information */
832 		task->tk_msg.rpc_resp = NULL;
833 	}
834 }
835 
836 
nfsd4_cb_recall_done(struct rpc_task * task,void * calldata)837 static void nfsd4_cb_recall_done(struct rpc_task *task, void *calldata)
838 {
839 	struct nfsd4_callback *cb = calldata;
840 	struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
841 	struct nfs4_client *clp = cb->cb_clp;
842 	struct rpc_clnt *current_rpc_client = clp->cl_cb_client;
843 
844 	nfsd4_cb_done(task, calldata);
845 
846 	if (current_rpc_client != task->tk_client) {
847 		/* We're shutting down or changing cl_cb_client; leave
848 		 * it to nfsd4_process_cb_update to restart the call if
849 		 * necessary. */
850 		return;
851 	}
852 
853 	if (cb->cb_done)
854 		return;
855 	switch (task->tk_status) {
856 	case 0:
857 		cb->cb_done = true;
858 		return;
859 	case -EBADHANDLE:
860 	case -NFS4ERR_BAD_STATEID:
861 		/* Race: client probably got cb_recall
862 		 * before open reply granting delegation */
863 		break;
864 	default:
865 		/* Network partition? */
866 		nfsd4_mark_cb_down(clp, task->tk_status);
867 	}
868 	if (dp->dl_retries--) {
869 		rpc_delay(task, 2*HZ);
870 		task->tk_status = 0;
871 		rpc_restart_call_prepare(task);
872 		return;
873 	}
874 	nfsd4_mark_cb_down(clp, task->tk_status);
875 	cb->cb_done = true;
876 }
877 
nfsd4_cb_recall_release(void * calldata)878 static void nfsd4_cb_recall_release(void *calldata)
879 {
880 	struct nfsd4_callback *cb = calldata;
881 	struct nfs4_client *clp = cb->cb_clp;
882 	struct nfs4_delegation *dp = container_of(cb, struct nfs4_delegation, dl_recall);
883 
884 	if (cb->cb_done) {
885 		spin_lock(&clp->cl_lock);
886 		list_del(&cb->cb_per_client);
887 		spin_unlock(&clp->cl_lock);
888 		nfs4_put_delegation(dp);
889 	}
890 }
891 
892 static const struct rpc_call_ops nfsd4_cb_recall_ops = {
893 	.rpc_call_prepare = nfsd4_cb_prepare,
894 	.rpc_call_done = nfsd4_cb_recall_done,
895 	.rpc_release = nfsd4_cb_recall_release,
896 };
897 
nfsd4_create_callback_queue(void)898 int nfsd4_create_callback_queue(void)
899 {
900 	callback_wq = create_singlethread_workqueue("nfsd4_callbacks");
901 	if (!callback_wq)
902 		return -ENOMEM;
903 	return 0;
904 }
905 
nfsd4_destroy_callback_queue(void)906 void nfsd4_destroy_callback_queue(void)
907 {
908 	destroy_workqueue(callback_wq);
909 }
910 
911 /* must be called under the state lock */
nfsd4_shutdown_callback(struct nfs4_client * clp)912 void nfsd4_shutdown_callback(struct nfs4_client *clp)
913 {
914 	set_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags);
915 	/*
916 	 * Note this won't actually result in a null callback;
917 	 * instead, nfsd4_do_callback_rpc() will detect the killed
918 	 * client, destroy the rpc client, and stop:
919 	 */
920 	do_probe_callback(clp);
921 	flush_workqueue(callback_wq);
922 }
923 
nfsd4_release_cb(struct nfsd4_callback * cb)924 static void nfsd4_release_cb(struct nfsd4_callback *cb)
925 {
926 	if (cb->cb_ops->rpc_release)
927 		cb->cb_ops->rpc_release(cb);
928 }
929 
930 /* requires cl_lock: */
__nfsd4_find_backchannel(struct nfs4_client * clp)931 static struct nfsd4_conn * __nfsd4_find_backchannel(struct nfs4_client *clp)
932 {
933 	struct nfsd4_session *s;
934 	struct nfsd4_conn *c;
935 
936 	list_for_each_entry(s, &clp->cl_sessions, se_perclnt) {
937 		list_for_each_entry(c, &s->se_conns, cn_persession) {
938 			if (c->cn_flags & NFS4_CDFC4_BACK)
939 				return c;
940 		}
941 	}
942 	return NULL;
943 }
944 
nfsd4_process_cb_update(struct nfsd4_callback * cb)945 static void nfsd4_process_cb_update(struct nfsd4_callback *cb)
946 {
947 	struct nfs4_cb_conn conn;
948 	struct nfs4_client *clp = cb->cb_clp;
949 	struct nfsd4_session *ses = NULL;
950 	struct nfsd4_conn *c;
951 	int err;
952 
953 	/*
954 	 * This is either an update, or the client dying; in either case,
955 	 * kill the old client:
956 	 */
957 	if (clp->cl_cb_client) {
958 		rpc_shutdown_client(clp->cl_cb_client);
959 		clp->cl_cb_client = NULL;
960 		put_rpccred(clp->cl_cb_cred);
961 		clp->cl_cb_cred = NULL;
962 	}
963 	if (clp->cl_cb_conn.cb_xprt) {
964 		svc_xprt_put(clp->cl_cb_conn.cb_xprt);
965 		clp->cl_cb_conn.cb_xprt = NULL;
966 	}
967 	if (test_bit(NFSD4_CLIENT_CB_KILL, &clp->cl_flags))
968 		return;
969 	spin_lock(&clp->cl_lock);
970 	/*
971 	 * Only serialized callback code is allowed to clear these
972 	 * flags; main nfsd code can only set them:
973 	 */
974 	BUG_ON(!(clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK));
975 	clear_bit(NFSD4_CLIENT_CB_UPDATE, &clp->cl_flags);
976 	memcpy(&conn, &cb->cb_clp->cl_cb_conn, sizeof(struct nfs4_cb_conn));
977 	c = __nfsd4_find_backchannel(clp);
978 	if (c) {
979 		svc_xprt_get(c->cn_xprt);
980 		conn.cb_xprt = c->cn_xprt;
981 		ses = c->cn_session;
982 	}
983 	spin_unlock(&clp->cl_lock);
984 
985 	err = setup_callback_client(clp, &conn, ses);
986 	if (err) {
987 		nfsd4_mark_cb_down(clp, err);
988 		return;
989 	}
990 	/* Yay, the callback channel's back! Restart any callbacks: */
991 	list_for_each_entry(cb, &clp->cl_callbacks, cb_per_client)
992 		run_nfsd4_cb(cb);
993 }
994 
nfsd4_do_callback_rpc(struct work_struct * w)995 static void nfsd4_do_callback_rpc(struct work_struct *w)
996 {
997 	struct nfsd4_callback *cb = container_of(w, struct nfsd4_callback, cb_work);
998 	struct nfs4_client *clp = cb->cb_clp;
999 	struct rpc_clnt *clnt;
1000 
1001 	if (clp->cl_flags & NFSD4_CLIENT_CB_FLAG_MASK)
1002 		nfsd4_process_cb_update(cb);
1003 
1004 	clnt = clp->cl_cb_client;
1005 	if (!clnt) {
1006 		/* Callback channel broken, or client killed; give up: */
1007 		nfsd4_release_cb(cb);
1008 		return;
1009 	}
1010 	cb->cb_msg.rpc_cred = clp->cl_cb_cred;
1011 	rpc_call_async(clnt, &cb->cb_msg, RPC_TASK_SOFT | RPC_TASK_SOFTCONN,
1012 			cb->cb_ops, cb);
1013 }
1014 
nfsd4_init_callback(struct nfsd4_callback * cb)1015 void nfsd4_init_callback(struct nfsd4_callback *cb)
1016 {
1017 	INIT_WORK(&cb->cb_work, nfsd4_do_callback_rpc);
1018 }
1019 
nfsd4_cb_recall(struct nfs4_delegation * dp)1020 void nfsd4_cb_recall(struct nfs4_delegation *dp)
1021 {
1022 	struct nfsd4_callback *cb = &dp->dl_recall;
1023 	struct nfs4_client *clp = dp->dl_stid.sc_client;
1024 
1025 	dp->dl_retries = 1;
1026 	cb->cb_op = dp;
1027 	cb->cb_clp = clp;
1028 	cb->cb_msg.rpc_proc = &nfs4_cb_procedures[NFSPROC4_CLNT_CB_RECALL];
1029 	cb->cb_msg.rpc_argp = cb;
1030 	cb->cb_msg.rpc_resp = cb;
1031 
1032 	cb->cb_ops = &nfsd4_cb_recall_ops;
1033 
1034 	INIT_LIST_HEAD(&cb->cb_per_client);
1035 	cb->cb_done = true;
1036 
1037 	run_nfsd4_cb(&dp->dl_recall);
1038 }
1039