xref: /openbmc/linux/fs/nfsd/nfsxdr.c (revision f9a82c48) 
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 #define NFSDDBG_FACILITY		NFSDDBG_XDR
13 
14 /*
15  * Mapping of S_IF* types to NFS file types
16  */
17 static u32	nfs_ftypes[] = {
18 	NFNON,  NFCHR,  NFCHR, NFBAD,
19 	NFDIR,  NFBAD,  NFBLK, NFBAD,
20 	NFREG,  NFBAD,  NFLNK, NFBAD,
21 	NFSOCK, NFBAD,  NFLNK, NFBAD,
22 };
23 
24 
25 /*
26  * XDR functions for basic NFS types
27  */
28 static __be32 *
29 decode_fh(__be32 *p, struct svc_fh *fhp)
30 {
31 	fh_init(fhp, NFS_FHSIZE);
32 	memcpy(&fhp->fh_handle.fh_base, p, NFS_FHSIZE);
33 	fhp->fh_handle.fh_size = NFS_FHSIZE;
34 
35 	/* FIXME: Look up export pointer here and verify
36 	 * Sun Secure RPC if requested */
37 	return p + (NFS_FHSIZE >> 2);
38 }
39 
40 /* Helper function for NFSv2 ACL code */
41 __be32 *nfs2svc_decode_fh(__be32 *p, struct svc_fh *fhp)
42 {
43 	return decode_fh(p, fhp);
44 }
45 
46 static __be32 *
47 encode_fh(__be32 *p, struct svc_fh *fhp)
48 {
49 	memcpy(p, &fhp->fh_handle.fh_base, NFS_FHSIZE);
50 	return p + (NFS_FHSIZE>> 2);
51 }
52 
53 /*
54  * Decode a file name and make sure that the path contains
55  * no slashes or null bytes.
56  */
57 static __be32 *
58 decode_filename(__be32 *p, char **namp, unsigned int *lenp)
59 {
60 	char		*name;
61 	unsigned int	i;
62 
63 	if ((p = xdr_decode_string_inplace(p, namp, lenp, NFS_MAXNAMLEN)) != NULL) {
64 		for (i = 0, name = *namp; i < *lenp; i++, name++) {
65 			if (*name == '\0' || *name == '/')
66 				return NULL;
67 		}
68 	}
69 
70 	return p;
71 }
72 
73 static __be32 *
74 decode_sattr(__be32 *p, struct iattr *iap)
75 {
76 	u32	tmp, tmp1;
77 
78 	iap->ia_valid = 0;
79 
80 	/* Sun client bug compatibility check: some sun clients seem to
81 	 * put 0xffff in the mode field when they mean 0xffffffff.
82 	 * Quoting the 4.4BSD nfs server code: Nah nah nah nah na nah.
83 	 */
84 	if ((tmp = ntohl(*p++)) != (u32)-1 && tmp != 0xffff) {
85 		iap->ia_valid |= ATTR_MODE;
86 		iap->ia_mode = tmp;
87 	}
88 	if ((tmp = ntohl(*p++)) != (u32)-1) {
89 		iap->ia_uid = make_kuid(&init_user_ns, tmp);
90 		if (uid_valid(iap->ia_uid))
91 			iap->ia_valid |= ATTR_UID;
92 	}
93 	if ((tmp = ntohl(*p++)) != (u32)-1) {
94 		iap->ia_gid = make_kgid(&init_user_ns, tmp);
95 		if (gid_valid(iap->ia_gid))
96 			iap->ia_valid |= ATTR_GID;
97 	}
98 	if ((tmp = ntohl(*p++)) != (u32)-1) {
99 		iap->ia_valid |= ATTR_SIZE;
100 		iap->ia_size = tmp;
101 	}
102 	tmp  = ntohl(*p++); tmp1 = ntohl(*p++);
103 	if (tmp != (u32)-1 && tmp1 != (u32)-1) {
104 		iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
105 		iap->ia_atime.tv_sec = tmp;
106 		iap->ia_atime.tv_nsec = tmp1 * 1000;
107 	}
108 	tmp  = ntohl(*p++); tmp1 = ntohl(*p++);
109 	if (tmp != (u32)-1 && tmp1 != (u32)-1) {
110 		iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
111 		iap->ia_mtime.tv_sec = tmp;
112 		iap->ia_mtime.tv_nsec = tmp1 * 1000;
113 		/*
114 		 * Passing the invalid value useconds=1000000 for mtime
115 		 * is a Sun convention for "set both mtime and atime to
116 		 * current server time".  It's needed to make permissions
117 		 * checks for the "touch" program across v2 mounts to
118 		 * Solaris and Irix boxes work correctly. See description of
119 		 * sattr in section 6.1 of "NFS Illustrated" by
120 		 * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
121 		 */
122 		if (tmp1 == 1000000)
123 			iap->ia_valid &= ~(ATTR_ATIME_SET|ATTR_MTIME_SET);
124 	}
125 	return p;
126 }
127 
128 static __be32 *
129 encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
130 	     struct kstat *stat)
131 {
132 	struct dentry	*dentry = fhp->fh_dentry;
133 	int type;
134 	struct timespec64 time;
135 	u32 f;
136 
137 	type = (stat->mode & S_IFMT);
138 
139 	*p++ = htonl(nfs_ftypes[type >> 12]);
140 	*p++ = htonl((u32) stat->mode);
141 	*p++ = htonl((u32) stat->nlink);
142 	*p++ = htonl((u32) from_kuid(&init_user_ns, stat->uid));
143 	*p++ = htonl((u32) from_kgid(&init_user_ns, stat->gid));
144 
145 	if (S_ISLNK(type) && stat->size > NFS_MAXPATHLEN) {
146 		*p++ = htonl(NFS_MAXPATHLEN);
147 	} else {
148 		*p++ = htonl((u32) stat->size);
149 	}
150 	*p++ = htonl((u32) stat->blksize);
151 	if (S_ISCHR(type) || S_ISBLK(type))
152 		*p++ = htonl(new_encode_dev(stat->rdev));
153 	else
154 		*p++ = htonl(0xffffffff);
155 	*p++ = htonl((u32) stat->blocks);
156 	switch (fsid_source(fhp)) {
157 	default:
158 	case FSIDSOURCE_DEV:
159 		*p++ = htonl(new_encode_dev(stat->dev));
160 		break;
161 	case FSIDSOURCE_FSID:
162 		*p++ = htonl((u32) fhp->fh_export->ex_fsid);
163 		break;
164 	case FSIDSOURCE_UUID:
165 		f = ((u32*)fhp->fh_export->ex_uuid)[0];
166 		f ^= ((u32*)fhp->fh_export->ex_uuid)[1];
167 		f ^= ((u32*)fhp->fh_export->ex_uuid)[2];
168 		f ^= ((u32*)fhp->fh_export->ex_uuid)[3];
169 		*p++ = htonl(f);
170 		break;
171 	}
172 	*p++ = htonl((u32) stat->ino);
173 	*p++ = htonl((u32) stat->atime.tv_sec);
174 	*p++ = htonl(stat->atime.tv_nsec ? stat->atime.tv_nsec / 1000 : 0);
175 	time = stat->mtime;
176 	lease_get_mtime(d_inode(dentry), &time);
177 	*p++ = htonl((u32) time.tv_sec);
178 	*p++ = htonl(time.tv_nsec ? time.tv_nsec / 1000 : 0);
179 	*p++ = htonl((u32) stat->ctime.tv_sec);
180 	*p++ = htonl(stat->ctime.tv_nsec ? stat->ctime.tv_nsec / 1000 : 0);
181 
182 	return p;
183 }
184 
185 /* Helper function for NFSv2 ACL code */
186 __be32 *nfs2svc_encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp, struct kstat *stat)
187 {
188 	return encode_fattr(rqstp, p, fhp, stat);
189 }
190 
191 /*
192  * XDR decode functions
193  */
194 int
195 nfssvc_decode_void(struct svc_rqst *rqstp, __be32 *p)
196 {
197 	return xdr_argsize_check(rqstp, p);
198 }
199 
200 int
201 nfssvc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p)
202 {
203 	struct nfsd_fhandle *args = rqstp->rq_argp;
204 
205 	p = decode_fh(p, &args->fh);
206 	if (!p)
207 		return 0;
208 	return xdr_argsize_check(rqstp, p);
209 }
210 
211 int
212 nfssvc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p)
213 {
214 	struct nfsd_sattrargs *args = rqstp->rq_argp;
215 
216 	p = decode_fh(p, &args->fh);
217 	if (!p)
218 		return 0;
219 	p = decode_sattr(p, &args->attrs);
220 
221 	return xdr_argsize_check(rqstp, p);
222 }
223 
224 int
225 nfssvc_decode_diropargs(struct svc_rqst *rqstp, __be32 *p)
226 {
227 	struct nfsd_diropargs *args = rqstp->rq_argp;
228 
229 	if (!(p = decode_fh(p, &args->fh))
230 	 || !(p = decode_filename(p, &args->name, &args->len)))
231 		return 0;
232 
233 	return xdr_argsize_check(rqstp, p);
234 }
235 
236 int
237 nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
238 {
239 	struct nfsd_readargs *args = rqstp->rq_argp;
240 	unsigned int len;
241 	int v;
242 	p = decode_fh(p, &args->fh);
243 	if (!p)
244 		return 0;
245 
246 	args->offset    = ntohl(*p++);
247 	len = args->count     = ntohl(*p++);
248 	p++; /* totalcount - unused */
249 
250 	len = min_t(unsigned int, len, NFSSVC_MAXBLKSIZE_V2);
251 
252 	/* set up somewhere to store response.
253 	 * We take pages, put them on reslist and include in iovec
254 	 */
255 	v=0;
256 	while (len > 0) {
257 		struct page *p = *(rqstp->rq_next_page++);
258 
259 		rqstp->rq_vec[v].iov_base = page_address(p);
260 		rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
261 		len -= rqstp->rq_vec[v].iov_len;
262 		v++;
263 	}
264 	args->vlen = v;
265 	return xdr_argsize_check(rqstp, p);
266 }
267 
268 int
269 nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
270 {
271 	struct nfsd_writeargs *args = rqstp->rq_argp;
272 	unsigned int len, hdr, dlen;
273 	struct kvec *head = rqstp->rq_arg.head;
274 
275 	p = decode_fh(p, &args->fh);
276 	if (!p)
277 		return 0;
278 
279 	p++;				/* beginoffset */
280 	args->offset = ntohl(*p++);	/* offset */
281 	p++;				/* totalcount */
282 	len = args->len = ntohl(*p++);
283 	/*
284 	 * The protocol specifies a maximum of 8192 bytes.
285 	 */
286 	if (len > NFSSVC_MAXBLKSIZE_V2)
287 		return 0;
288 
289 	/*
290 	 * Check to make sure that we got the right number of
291 	 * bytes.
292 	 */
293 	hdr = (void*)p - head->iov_base;
294 	if (hdr > head->iov_len)
295 		return 0;
296 	dlen = head->iov_len + rqstp->rq_arg.page_len - hdr;
297 
298 	/*
299 	 * Round the length of the data which was specified up to
300 	 * the next multiple of XDR units and then compare that
301 	 * against the length which was actually received.
302 	 * Note that when RPCSEC/GSS (for example) is used, the
303 	 * data buffer can be padded so dlen might be larger
304 	 * than required.  It must never be smaller.
305 	 */
306 	if (dlen < XDR_QUADLEN(len)*4)
307 		return 0;
308 
309 	args->first.iov_base = (void *)p;
310 	args->first.iov_len = head->iov_len - hdr;
311 	return 1;
312 }
313 
314 int
315 nfssvc_decode_createargs(struct svc_rqst *rqstp, __be32 *p)
316 {
317 	struct nfsd_createargs *args = rqstp->rq_argp;
318 
319 	if (   !(p = decode_fh(p, &args->fh))
320 	    || !(p = decode_filename(p, &args->name, &args->len)))
321 		return 0;
322 	p = decode_sattr(p, &args->attrs);
323 
324 	return xdr_argsize_check(rqstp, p);
325 }
326 
327 int
328 nfssvc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p)
329 {
330 	struct nfsd_renameargs *args = rqstp->rq_argp;
331 
332 	if (!(p = decode_fh(p, &args->ffh))
333 	 || !(p = decode_filename(p, &args->fname, &args->flen))
334 	 || !(p = decode_fh(p, &args->tfh))
335 	 || !(p = decode_filename(p, &args->tname, &args->tlen)))
336 		return 0;
337 
338 	return xdr_argsize_check(rqstp, p);
339 }
340 
341 int
342 nfssvc_decode_readlinkargs(struct svc_rqst *rqstp, __be32 *p)
343 {
344 	struct nfsd_readlinkargs *args = rqstp->rq_argp;
345 
346 	p = decode_fh(p, &args->fh);
347 	if (!p)
348 		return 0;
349 	args->buffer = page_address(*(rqstp->rq_next_page++));
350 
351 	return xdr_argsize_check(rqstp, p);
352 }
353 
354 int
355 nfssvc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
356 {
357 	struct nfsd_linkargs *args = rqstp->rq_argp;
358 
359 	if (!(p = decode_fh(p, &args->ffh))
360 	 || !(p = decode_fh(p, &args->tfh))
361 	 || !(p = decode_filename(p, &args->tname, &args->tlen)))
362 		return 0;
363 
364 	return xdr_argsize_check(rqstp, p);
365 }
366 
367 int
368 nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
369 {
370 	struct nfsd_symlinkargs *args = rqstp->rq_argp;
371 	char *base = (char *)p;
372 	size_t xdrlen;
373 
374 	if (   !(p = decode_fh(p, &args->ffh))
375 	    || !(p = decode_filename(p, &args->fname, &args->flen)))
376 		return 0;
377 
378 	args->tlen = ntohl(*p++);
379 	if (args->tlen == 0)
380 		return 0;
381 
382 	args->first.iov_base = p;
383 	args->first.iov_len = rqstp->rq_arg.head[0].iov_len;
384 	args->first.iov_len -= (char *)p - base;
385 
386 	/* This request is never larger than a page. Therefore,
387 	 * transport will deliver either:
388 	 * 1. pathname in the pagelist -> sattr is in the tail.
389 	 * 2. everything in the head buffer -> sattr is in the head.
390 	 */
391 	if (rqstp->rq_arg.page_len) {
392 		if (args->tlen != rqstp->rq_arg.page_len)
393 			return 0;
394 		p = rqstp->rq_arg.tail[0].iov_base;
395 	} else {
396 		xdrlen = XDR_QUADLEN(args->tlen);
397 		if (xdrlen > args->first.iov_len - (8 * sizeof(__be32)))
398 			return 0;
399 		p += xdrlen;
400 	}
401 	decode_sattr(p, &args->attrs);
402 
403 	return 1;
404 }
405 
406 int
407 nfssvc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
408 {
409 	struct nfsd_readdirargs *args = rqstp->rq_argp;
410 
411 	p = decode_fh(p, &args->fh);
412 	if (!p)
413 		return 0;
414 	args->cookie = ntohl(*p++);
415 	args->count  = ntohl(*p++);
416 	args->count  = min_t(u32, args->count, PAGE_SIZE);
417 	args->buffer = page_address(*(rqstp->rq_next_page++));
418 
419 	return xdr_argsize_check(rqstp, p);
420 }
421 
422 /*
423  * XDR encode functions
424  */
425 int
426 nfssvc_encode_void(struct svc_rqst *rqstp, __be32 *p)
427 {
428 	return xdr_ressize_check(rqstp, p);
429 }
430 
431 int
432 nfssvc_encode_attrstat(struct svc_rqst *rqstp, __be32 *p)
433 {
434 	struct nfsd_attrstat *resp = rqstp->rq_resp;
435 
436 	p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
437 	return xdr_ressize_check(rqstp, p);
438 }
439 
440 int
441 nfssvc_encode_diropres(struct svc_rqst *rqstp, __be32 *p)
442 {
443 	struct nfsd_diropres *resp = rqstp->rq_resp;
444 
445 	p = encode_fh(p, &resp->fh);
446 	p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
447 	return xdr_ressize_check(rqstp, p);
448 }
449 
450 int
451 nfssvc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
452 {
453 	struct nfsd_readlinkres *resp = rqstp->rq_resp;
454 
455 	*p++ = htonl(resp->len);
456 	xdr_ressize_check(rqstp, p);
457 	rqstp->rq_res.page_len = resp->len;
458 	if (resp->len & 3) {
459 		/* need to pad the tail */
460 		rqstp->rq_res.tail[0].iov_base = p;
461 		*p = 0;
462 		rqstp->rq_res.tail[0].iov_len = 4 - (resp->len&3);
463 	}
464 	return 1;
465 }
466 
467 int
468 nfssvc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
469 {
470 	struct nfsd_readres *resp = rqstp->rq_resp;
471 
472 	p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
473 	*p++ = htonl(resp->count);
474 	xdr_ressize_check(rqstp, p);
475 
476 	/* now update rqstp->rq_res to reflect data as well */
477 	rqstp->rq_res.page_len = resp->count;
478 	if (resp->count & 3) {
479 		/* need to pad the tail */
480 		rqstp->rq_res.tail[0].iov_base = p;
481 		*p = 0;
482 		rqstp->rq_res.tail[0].iov_len = 4 - (resp->count&3);
483 	}
484 	return 1;
485 }
486 
487 int
488 nfssvc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
489 {
490 	struct nfsd_readdirres *resp = rqstp->rq_resp;
491 
492 	xdr_ressize_check(rqstp, p);
493 	p = resp->buffer;
494 	*p++ = 0;			/* no more entries */
495 	*p++ = htonl((resp->common.err == nfserr_eof));
496 	rqstp->rq_res.page_len = (((unsigned long)p-1) & ~PAGE_MASK)+1;
497 
498 	return 1;
499 }
500 
501 int
502 nfssvc_encode_statfsres(struct svc_rqst *rqstp, __be32 *p)
503 {
504 	struct nfsd_statfsres *resp = rqstp->rq_resp;
505 	struct kstatfs	*stat = &resp->stats;
506 
507 	*p++ = htonl(NFSSVC_MAXBLKSIZE_V2);	/* max transfer size */
508 	*p++ = htonl(stat->f_bsize);
509 	*p++ = htonl(stat->f_blocks);
510 	*p++ = htonl(stat->f_bfree);
511 	*p++ = htonl(stat->f_bavail);
512 	return xdr_ressize_check(rqstp, p);
513 }
514 
515 int
516 nfssvc_encode_entry(void *ccdv, const char *name,
517 		    int namlen, loff_t offset, u64 ino, unsigned int d_type)
518 {
519 	struct readdir_cd *ccd = ccdv;
520 	struct nfsd_readdirres *cd = container_of(ccd, struct nfsd_readdirres, common);
521 	__be32	*p = cd->buffer;
522 	int	buflen, slen;
523 
524 	/*
525 	dprintk("nfsd: entry(%.*s off %ld ino %ld)\n",
526 			namlen, name, offset, ino);
527 	 */
528 
529 	if (offset > ~((u32) 0)) {
530 		cd->common.err = nfserr_fbig;
531 		return -EINVAL;
532 	}
533 	if (cd->offset)
534 		*cd->offset = htonl(offset);
535 
536 	/* truncate filename */
537 	namlen = min(namlen, NFS2_MAXNAMLEN);
538 	slen = XDR_QUADLEN(namlen);
539 
540 	if ((buflen = cd->buflen - slen - 4) < 0) {
541 		cd->common.err = nfserr_toosmall;
542 		return -EINVAL;
543 	}
544 	if (ino > ~((u32) 0)) {
545 		cd->common.err = nfserr_fbig;
546 		return -EINVAL;
547 	}
548 	*p++ = xdr_one;				/* mark entry present */
549 	*p++ = htonl((u32) ino);		/* file id */
550 	p    = xdr_encode_array(p, name, namlen);/* name length & name */
551 	cd->offset = p;			/* remember pointer */
552 	*p++ = htonl(~0U);		/* offset of next entry */
553 
554 	cd->buflen = buflen;
555 	cd->buffer = p;
556 	cd->common.err = nfs_ok;
557 	return 0;
558 }
559 
560 /*
561  * XDR release functions
562  */
563 void
564 nfssvc_release_fhandle(struct svc_rqst *rqstp)
565 {
566 	struct nfsd_fhandle *resp = rqstp->rq_resp;
567 
568 	fh_put(&resp->fh);
569 }
570