1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * XDR support for nfsd
4 *
5 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
6 */
7
8 #include "vfs.h"
9 #include "xdr.h"
10 #include "auth.h"
11
12 /*
13 * Mapping of S_IF* types to NFS file types
14 */
15 static const u32 nfs_ftypes[] = {
16 NFNON, NFCHR, NFCHR, NFBAD,
17 NFDIR, NFBAD, NFBLK, NFBAD,
18 NFREG, NFBAD, NFLNK, NFBAD,
19 NFSOCK, NFBAD, NFLNK, NFBAD,
20 };
21
22
23 /*
24 * Basic NFSv2 data types (RFC 1094 Section 2.3)
25 */
26
27 /**
28 * svcxdr_encode_stat - Encode an NFSv2 status code
29 * @xdr: XDR stream
30 * @status: status value to encode
31 *
32 * Return values:
33 * %false: Send buffer space was exhausted
34 * %true: Success
35 */
36 bool
37 svcxdr_encode_stat(struct xdr_stream *xdr, __be32 status)
38 {
39 __be32 *p;
40
41 p = xdr_reserve_space(xdr, sizeof(status));
42 if (!p)
43 return false;
44 *p = status;
45
46 return true;
47 }
48
49 /**
50 * svcxdr_decode_fhandle - Decode an NFSv2 file handle
51 * @xdr: XDR stream positioned at an encoded NFSv2 FH
52 * @fhp: OUT: filled-in server file handle
53 *
54 * Return values:
55 * %false: The encoded file handle was not valid
56 * %true: @fhp has been initialized
57 */
58 bool
59 svcxdr_decode_fhandle(struct xdr_stream *xdr, struct svc_fh *fhp)
60 {
61 __be32 *p;
62
63 p = xdr_inline_decode(xdr, NFS_FHSIZE);
64 if (!p)
65 return false;
66 fh_init(fhp, NFS_FHSIZE);
67 memcpy(&fhp->fh_handle.fh_raw, p, NFS_FHSIZE);
68 fhp->fh_handle.fh_size = NFS_FHSIZE;
69
70 return true;
71 }
72
73 static bool
74 svcxdr_encode_fhandle(struct xdr_stream *xdr, const struct svc_fh *fhp)
75 {
76 __be32 *p;
77
78 p = xdr_reserve_space(xdr, NFS_FHSIZE);
79 if (!p)
80 return false;
81 memcpy(p, &fhp->fh_handle.fh_raw, NFS_FHSIZE);
82
83 return true;
84 }
85
86 static __be32 *
87 encode_timeval(__be32 *p, const struct timespec64 *time)
88 {
89 *p++ = cpu_to_be32((u32)time->tv_sec);
90 if (time->tv_nsec)
91 *p++ = cpu_to_be32(time->tv_nsec / NSEC_PER_USEC);
92 else
93 *p++ = xdr_zero;
94 return p;
95 }
96
97 static bool
98 svcxdr_decode_filename(struct xdr_stream *xdr, char **name, unsigned int *len)
99 {
100 u32 size, i;
101 __be32 *p;
102 char *c;
103
104 if (xdr_stream_decode_u32(xdr, &size) < 0)
105 return false;
106 if (size == 0 || size > NFS_MAXNAMLEN)
107 return false;
108 p = xdr_inline_decode(xdr, size);
109 if (!p)
110 return false;
111
112 *len = size;
113 *name = (char *)p;
114 for (i = 0, c = *name; i < size; i++, c++)
115 if (*c == '\0' || *c == '/')
116 return false;
117
118 return true;
119 }
120
121 static bool
122 svcxdr_decode_diropargs(struct xdr_stream *xdr, struct svc_fh *fhp,
123 char **name, unsigned int *len)
124 {
125 return svcxdr_decode_fhandle(xdr, fhp) &&
126 svcxdr_decode_filename(xdr, name, len);
127 }
128
129 static bool
130 svcxdr_decode_sattr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
131 struct iattr *iap)
132 {
133 u32 tmp1, tmp2;
134 __be32 *p;
135
136 p = xdr_inline_decode(xdr, XDR_UNIT * 8);
137 if (!p)
138 return false;
139
140 iap->ia_valid = 0;
141
142 /*
143 * Some Sun clients put 0xffff in the mode field when they
144 * mean 0xffffffff.
145 */
146 tmp1 = be32_to_cpup(p++);
147 if (tmp1 != (u32)-1 && tmp1 != 0xffff) {
148 iap->ia_valid |= ATTR_MODE;
149 iap->ia_mode = tmp1;
150 }
151
152 tmp1 = be32_to_cpup(p++);
153 if (tmp1 != (u32)-1) {
154 iap->ia_uid = make_kuid(nfsd_user_namespace(rqstp), tmp1);
155 if (uid_valid(iap->ia_uid))
156 iap->ia_valid |= ATTR_UID;
157 }
158
159 tmp1 = be32_to_cpup(p++);
160 if (tmp1 != (u32)-1) {
161 iap->ia_gid = make_kgid(nfsd_user_namespace(rqstp), tmp1);
162 if (gid_valid(iap->ia_gid))
163 iap->ia_valid |= ATTR_GID;
164 }
165
166 tmp1 = be32_to_cpup(p++);
167 if (tmp1 != (u32)-1) {
168 iap->ia_valid |= ATTR_SIZE;
169 iap->ia_size = tmp1;
170 }
171
172 tmp1 = be32_to_cpup(p++);
173 tmp2 = be32_to_cpup(p++);
174 if (tmp1 != (u32)-1 && tmp2 != (u32)-1) {
175 iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
176 iap->ia_atime.tv_sec = tmp1;
177 iap->ia_atime.tv_nsec = tmp2 * NSEC_PER_USEC;
178 }
179
180 tmp1 = be32_to_cpup(p++);
181 tmp2 = be32_to_cpup(p++);
182 if (tmp1 != (u32)-1 && tmp2 != (u32)-1) {
183 iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
184 iap->ia_mtime.tv_sec = tmp1;
185 iap->ia_mtime.tv_nsec = tmp2 * NSEC_PER_USEC;
186 /*
187 * Passing the invalid value useconds=1000000 for mtime
188 * is a Sun convention for "set both mtime and atime to
189 * current server time". It's needed to make permissions
190 * checks for the "touch" program across v2 mounts to
191 * Solaris and Irix boxes work correctly. See description of
192 * sattr in section 6.1 of "NFS Illustrated" by
193 * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
194 */
195 if (tmp2 == 1000000)
196 iap->ia_valid &= ~(ATTR_ATIME_SET|ATTR_MTIME_SET);
197 }
198
199 return true;
200 }
201
202 /**
203 * svcxdr_encode_fattr - Encode NFSv2 file attributes
204 * @rqstp: Context of a completed RPC transaction
205 * @xdr: XDR stream
206 * @fhp: File handle to encode
207 * @stat: Attributes to encode
208 *
209 * Return values:
210 * %false: Send buffer space was exhausted
211 * %true: Success
212 */
213 bool
214 svcxdr_encode_fattr(struct svc_rqst *rqstp, struct xdr_stream *xdr,
215 const struct svc_fh *fhp, const struct kstat *stat)
216 {
217 struct user_namespace *userns = nfsd_user_namespace(rqstp);
218 struct dentry *dentry = fhp->fh_dentry;
219 int type = stat->mode & S_IFMT;
220 struct timespec64 time;
221 __be32 *p;
222 u32 fsid;
223
224 p = xdr_reserve_space(xdr, XDR_UNIT * 17);
225 if (!p)
226 return false;
227
228 *p++ = cpu_to_be32(nfs_ftypes[type >> 12]);
229 *p++ = cpu_to_be32((u32)stat->mode);
230 *p++ = cpu_to_be32((u32)stat->nlink);
231 *p++ = cpu_to_be32((u32)from_kuid_munged(userns, stat->uid));
232 *p++ = cpu_to_be32((u32)from_kgid_munged(userns, stat->gid));
233
234 if (S_ISLNK(type) && stat->size > NFS_MAXPATHLEN)
235 *p++ = cpu_to_be32(NFS_MAXPATHLEN);
236 else
237 *p++ = cpu_to_be32((u32) stat->size);
238 *p++ = cpu_to_be32((u32) stat->blksize);
239 if (S_ISCHR(type) || S_ISBLK(type))
240 *p++ = cpu_to_be32(new_encode_dev(stat->rdev));
241 else
242 *p++ = cpu_to_be32(0xffffffff);
243 *p++ = cpu_to_be32((u32)stat->blocks);
244
245 switch (fsid_source(fhp)) {
246 case FSIDSOURCE_FSID:
247 fsid = (u32)fhp->fh_export->ex_fsid;
248 break;
249 case FSIDSOURCE_UUID:
250 fsid = ((u32 *)fhp->fh_export->ex_uuid)[0];
251 fsid ^= ((u32 *)fhp->fh_export->ex_uuid)[1];
252 fsid ^= ((u32 *)fhp->fh_export->ex_uuid)[2];
253 fsid ^= ((u32 *)fhp->fh_export->ex_uuid)[3];
254 break;
255 default:
256 fsid = new_encode_dev(stat->dev);
257 break;
258 }
259 *p++ = cpu_to_be32(fsid);
260
261 *p++ = cpu_to_be32((u32)stat->ino);
262 p = encode_timeval(p, &stat->atime);
263 time = stat->mtime;
264 lease_get_mtime(d_inode(dentry), &time);
265 p = encode_timeval(p, &time);
266 encode_timeval(p, &stat->ctime);
267
268 return true;
269 }
270
271 /*
272 * XDR decode functions
273 */
274
275 bool
276 nfssvc_decode_fhandleargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
277 {
278 struct nfsd_fhandle *args = rqstp->rq_argp;
279
280 return svcxdr_decode_fhandle(xdr, &args->fh);
281 }
282
283 bool
284 nfssvc_decode_sattrargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
285 {
286 struct nfsd_sattrargs *args = rqstp->rq_argp;
287
288 return svcxdr_decode_fhandle(xdr, &args->fh) &&
289 svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
290 }
291
292 bool
293 nfssvc_decode_diropargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
294 {
295 struct nfsd_diropargs *args = rqstp->rq_argp;
296
297 return svcxdr_decode_diropargs(xdr, &args->fh, &args->name, &args->len);
298 }
299
300 bool
301 nfssvc_decode_readargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
302 {
303 struct nfsd_readargs *args = rqstp->rq_argp;
304 u32 totalcount;
305
306 if (!svcxdr_decode_fhandle(xdr, &args->fh))
307 return false;
308 if (xdr_stream_decode_u32(xdr, &args->offset) < 0)
309 return false;
310 if (xdr_stream_decode_u32(xdr, &args->count) < 0)
311 return false;
312 /* totalcount is ignored */
313 if (xdr_stream_decode_u32(xdr, &totalcount) < 0)
314 return false;
315
316 return true;
317 }
318
319 bool
320 nfssvc_decode_writeargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
321 {
322 struct nfsd_writeargs *args = rqstp->rq_argp;
323 u32 beginoffset, totalcount;
324
325 if (!svcxdr_decode_fhandle(xdr, &args->fh))
326 return false;
327 /* beginoffset is ignored */
328 if (xdr_stream_decode_u32(xdr, &beginoffset) < 0)
329 return false;
330 if (xdr_stream_decode_u32(xdr, &args->offset) < 0)
331 return false;
332 /* totalcount is ignored */
333 if (xdr_stream_decode_u32(xdr, &totalcount) < 0)
334 return false;
335
336 /* opaque data */
337 if (xdr_stream_decode_u32(xdr, &args->len) < 0)
338 return false;
339 if (args->len > NFSSVC_MAXBLKSIZE_V2)
340 return false;
341
342 return xdr_stream_subsegment(xdr, &args->payload, args->len);
343 }
344
345 bool
346 nfssvc_decode_createargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
347 {
348 struct nfsd_createargs *args = rqstp->rq_argp;
349
350 return svcxdr_decode_diropargs(xdr, &args->fh,
351 &args->name, &args->len) &&
352 svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
353 }
354
355 bool
356 nfssvc_decode_renameargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
357 {
358 struct nfsd_renameargs *args = rqstp->rq_argp;
359
360 return svcxdr_decode_diropargs(xdr, &args->ffh,
361 &args->fname, &args->flen) &&
362 svcxdr_decode_diropargs(xdr, &args->tfh,
363 &args->tname, &args->tlen);
364 }
365
366 bool
367 nfssvc_decode_linkargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
368 {
369 struct nfsd_linkargs *args = rqstp->rq_argp;
370
371 return svcxdr_decode_fhandle(xdr, &args->ffh) &&
372 svcxdr_decode_diropargs(xdr, &args->tfh,
373 &args->tname, &args->tlen);
374 }
375
376 bool
377 nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
378 {
379 struct nfsd_symlinkargs *args = rqstp->rq_argp;
380 struct kvec *head = rqstp->rq_arg.head;
381
382 if (!svcxdr_decode_diropargs(xdr, &args->ffh, &args->fname, &args->flen))
383 return false;
384 if (xdr_stream_decode_u32(xdr, &args->tlen) < 0)
385 return false;
386 if (args->tlen == 0)
387 return false;
388
389 args->first.iov_len = head->iov_len - xdr_stream_pos(xdr);
390 args->first.iov_base = xdr_inline_decode(xdr, args->tlen);
391 if (!args->first.iov_base)
392 return false;
393 return svcxdr_decode_sattr(rqstp, xdr, &args->attrs);
394 }
395
396 bool
397 nfssvc_decode_readdirargs(struct svc_rqst *rqstp, struct xdr_stream *xdr)
398 {
399 struct nfsd_readdirargs *args = rqstp->rq_argp;
400
401 if (!svcxdr_decode_fhandle(xdr, &args->fh))
402 return false;
403 if (xdr_stream_decode_u32(xdr, &args->cookie) < 0)
404 return false;
405 if (xdr_stream_decode_u32(xdr, &args->count) < 0)
406 return false;
407
408 return true;
409 }
410
411 /*
412 * XDR encode functions
413 */
414
415 bool
416 nfssvc_encode_statres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
417 {
418 struct nfsd_stat *resp = rqstp->rq_resp;
419
420 return svcxdr_encode_stat(xdr, resp->status);
421 }
422
423 bool
424 nfssvc_encode_attrstatres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
425 {
426 struct nfsd_attrstat *resp = rqstp->rq_resp;
427
428 if (!svcxdr_encode_stat(xdr, resp->status))
429 return false;
430 switch (resp->status) {
431 case nfs_ok:
432 if (!svcxdr_encode_fattr(rqstp, xdr, &resp->fh, &resp->stat))
433 return false;
434 break;
435 }
436
437 return true;
438 }
439
440 bool
441 nfssvc_encode_diropres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
442 {
443 struct nfsd_diropres *resp = rqstp->rq_resp;
444
445 if (!svcxdr_encode_stat(xdr, resp->status))
446 return false;
447 switch (resp->status) {
448 case nfs_ok:
449 if (!svcxdr_encode_fhandle(xdr, &resp->fh))
450 return false;
451 if (!svcxdr_encode_fattr(rqstp, xdr, &resp->fh, &resp->stat))
452 return false;
453 break;
454 }
455
456 return true;
457 }
458
459 bool
460 nfssvc_encode_readlinkres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
461 {
462 struct nfsd_readlinkres *resp = rqstp->rq_resp;
463 struct kvec *head = rqstp->rq_res.head;
464
465 if (!svcxdr_encode_stat(xdr, resp->status))
466 return false;
467 switch (resp->status) {
468 case nfs_ok:
469 if (xdr_stream_encode_u32(xdr, resp->len) < 0)
470 return false;
471 svcxdr_encode_opaque_pages(rqstp, xdr, &resp->page, 0,
472 resp->len);
473 if (svc_encode_result_payload(rqstp, head->iov_len, resp->len) < 0)
474 return false;
475 break;
476 }
477
478 return true;
479 }
480
481 bool
482 nfssvc_encode_readres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
483 {
484 struct nfsd_readres *resp = rqstp->rq_resp;
485 struct kvec *head = rqstp->rq_res.head;
486
487 if (!svcxdr_encode_stat(xdr, resp->status))
488 return false;
489 switch (resp->status) {
490 case nfs_ok:
491 if (!svcxdr_encode_fattr(rqstp, xdr, &resp->fh, &resp->stat))
492 return false;
493 if (xdr_stream_encode_u32(xdr, resp->count) < 0)
494 return false;
495 svcxdr_encode_opaque_pages(rqstp, xdr, resp->pages,
496 rqstp->rq_res.page_base,
497 resp->count);
498 if (svc_encode_result_payload(rqstp, head->iov_len, resp->count) < 0)
499 return false;
500 break;
501 }
502
503 return true;
504 }
505
506 bool
507 nfssvc_encode_readdirres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
508 {
509 struct nfsd_readdirres *resp = rqstp->rq_resp;
510 struct xdr_buf *dirlist = &resp->dirlist;
511
512 if (!svcxdr_encode_stat(xdr, resp->status))
513 return false;
514 switch (resp->status) {
515 case nfs_ok:
516 svcxdr_encode_opaque_pages(rqstp, xdr, dirlist->pages, 0,
517 dirlist->len);
518 /* no more entries */
519 if (xdr_stream_encode_item_absent(xdr) < 0)
520 return false;
521 if (xdr_stream_encode_bool(xdr, resp->common.err == nfserr_eof) < 0)
522 return false;
523 break;
524 }
525
526 return true;
527 }
528
529 bool
530 nfssvc_encode_statfsres(struct svc_rqst *rqstp, struct xdr_stream *xdr)
531 {
532 struct nfsd_statfsres *resp = rqstp->rq_resp;
533 struct kstatfs *stat = &resp->stats;
534 __be32 *p;
535
536 if (!svcxdr_encode_stat(xdr, resp->status))
537 return false;
538 switch (resp->status) {
539 case nfs_ok:
540 p = xdr_reserve_space(xdr, XDR_UNIT * 5);
541 if (!p)
542 return false;
543 *p++ = cpu_to_be32(NFSSVC_MAXBLKSIZE_V2);
544 *p++ = cpu_to_be32(stat->f_bsize);
545 *p++ = cpu_to_be32(stat->f_blocks);
546 *p++ = cpu_to_be32(stat->f_bfree);
547 *p = cpu_to_be32(stat->f_bavail);
548 break;
549 }
550
551 return true;
552 }
553
554 /**
555 * nfssvc_encode_nfscookie - Encode a directory offset cookie
556 * @resp: readdir result context
557 * @offset: offset cookie to encode
558 *
559 * The buffer space for the offset cookie has already been reserved
560 * by svcxdr_encode_entry_common().
561 */
562 void nfssvc_encode_nfscookie(struct nfsd_readdirres *resp, u32 offset)
563 {
564 __be32 cookie = cpu_to_be32(offset);
565
566 if (!resp->cookie_offset)
567 return;
568
569 write_bytes_to_xdr_buf(&resp->dirlist, resp->cookie_offset, &cookie,
570 sizeof(cookie));
571 resp->cookie_offset = 0;
572 }
573
574 static bool
575 svcxdr_encode_entry_common(struct nfsd_readdirres *resp, const char *name,
576 int namlen, loff_t offset, u64 ino)
577 {
578 struct xdr_buf *dirlist = &resp->dirlist;
579 struct xdr_stream *xdr = &resp->xdr;
580
581 if (xdr_stream_encode_item_present(xdr) < 0)
582 return false;
583 /* fileid */
584 if (xdr_stream_encode_u32(xdr, (u32)ino) < 0)
585 return false;
586 /* name */
587 if (xdr_stream_encode_opaque(xdr, name, min(namlen, NFS2_MAXNAMLEN)) < 0)
588 return false;
589 /* cookie */
590 resp->cookie_offset = dirlist->len;
591 if (xdr_stream_encode_u32(xdr, ~0U) < 0)
592 return false;
593
594 return true;
595 }
596
597 /**
598 * nfssvc_encode_entry - encode one NFSv2 READDIR entry
599 * @data: directory context
600 * @name: name of the object to be encoded
601 * @namlen: length of that name, in bytes
602 * @offset: the offset of the previous entry
603 * @ino: the fileid of this entry
604 * @d_type: unused
605 *
606 * Return values:
607 * %0: Entry was successfully encoded.
608 * %-EINVAL: An encoding problem occured, secondary status code in resp->common.err
609 *
610 * On exit, the following fields are updated:
611 * - resp->xdr
612 * - resp->common.err
613 * - resp->cookie_offset
614 */
615 int nfssvc_encode_entry(void *data, const char *name, int namlen,
616 loff_t offset, u64 ino, unsigned int d_type)
617 {
618 struct readdir_cd *ccd = data;
619 struct nfsd_readdirres *resp = container_of(ccd,
620 struct nfsd_readdirres,
621 common);
622 unsigned int starting_length = resp->dirlist.len;
623
624 /* The offset cookie for the previous entry */
625 nfssvc_encode_nfscookie(resp, offset);
626
627 if (!svcxdr_encode_entry_common(resp, name, namlen, offset, ino))
628 goto out_toosmall;
629
630 xdr_commit_encode(&resp->xdr);
631 resp->common.err = nfs_ok;
632 return 0;
633
634 out_toosmall:
635 resp->cookie_offset = 0;
636 resp->common.err = nfserr_toosmall;
637 resp->dirlist.len = starting_length;
638 return -EINVAL;
639 }
640
641 /*
642 * XDR release functions
643 */
644 void nfssvc_release_attrstat(struct svc_rqst *rqstp)
645 {
646 struct nfsd_attrstat *resp = rqstp->rq_resp;
647
648 fh_put(&resp->fh);
649 }
650
651 void nfssvc_release_diropres(struct svc_rqst *rqstp)
652 {
653 struct nfsd_diropres *resp = rqstp->rq_resp;
654
655 fh_put(&resp->fh);
656 }
657
658 void nfssvc_release_readres(struct svc_rqst *rqstp)
659 {
660 struct nfsd_readres *resp = rqstp->rq_resp;
661
662 fh_put(&resp->fh);
663 }
664
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