xref: /openbmc/linux/fs/nfsd/nfsxdr.c (revision 550987be) 
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_pathname(__be32 *p, char **namp, unsigned int *lenp)
75 {
76 	char		*name;
77 	unsigned int	i;
78 
79 	if ((p = xdr_decode_string_inplace(p, namp, lenp, NFS_MAXPATHLEN)) != NULL) {
80 		for (i = 0, name = *namp; i < *lenp; i++, name++) {
81 			if (*name == '\0')
82 				return NULL;
83 		}
84 	}
85 
86 	return p;
87 }
88 
89 static __be32 *
90 decode_sattr(__be32 *p, struct iattr *iap)
91 {
92 	u32	tmp, tmp1;
93 
94 	iap->ia_valid = 0;
95 
96 	/* Sun client bug compatibility check: some sun clients seem to
97 	 * put 0xffff in the mode field when they mean 0xffffffff.
98 	 * Quoting the 4.4BSD nfs server code: Nah nah nah nah na nah.
99 	 */
100 	if ((tmp = ntohl(*p++)) != (u32)-1 && tmp != 0xffff) {
101 		iap->ia_valid |= ATTR_MODE;
102 		iap->ia_mode = tmp;
103 	}
104 	if ((tmp = ntohl(*p++)) != (u32)-1) {
105 		iap->ia_uid = make_kuid(&init_user_ns, tmp);
106 		if (uid_valid(iap->ia_uid))
107 			iap->ia_valid |= ATTR_UID;
108 	}
109 	if ((tmp = ntohl(*p++)) != (u32)-1) {
110 		iap->ia_gid = make_kgid(&init_user_ns, tmp);
111 		if (gid_valid(iap->ia_gid))
112 			iap->ia_valid |= ATTR_GID;
113 	}
114 	if ((tmp = ntohl(*p++)) != (u32)-1) {
115 		iap->ia_valid |= ATTR_SIZE;
116 		iap->ia_size = tmp;
117 	}
118 	tmp  = ntohl(*p++); tmp1 = ntohl(*p++);
119 	if (tmp != (u32)-1 && tmp1 != (u32)-1) {
120 		iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
121 		iap->ia_atime.tv_sec = tmp;
122 		iap->ia_atime.tv_nsec = tmp1 * 1000;
123 	}
124 	tmp  = ntohl(*p++); tmp1 = ntohl(*p++);
125 	if (tmp != (u32)-1 && tmp1 != (u32)-1) {
126 		iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
127 		iap->ia_mtime.tv_sec = tmp;
128 		iap->ia_mtime.tv_nsec = tmp1 * 1000;
129 		/*
130 		 * Passing the invalid value useconds=1000000 for mtime
131 		 * is a Sun convention for "set both mtime and atime to
132 		 * current server time".  It's needed to make permissions
133 		 * checks for the "touch" program across v2 mounts to
134 		 * Solaris and Irix boxes work correctly. See description of
135 		 * sattr in section 6.1 of "NFS Illustrated" by
136 		 * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
137 		 */
138 		if (tmp1 == 1000000)
139 			iap->ia_valid &= ~(ATTR_ATIME_SET|ATTR_MTIME_SET);
140 	}
141 	return p;
142 }
143 
144 static __be32 *
145 encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
146 	     struct kstat *stat)
147 {
148 	struct dentry	*dentry = fhp->fh_dentry;
149 	int type;
150 	struct timespec time;
151 	u32 f;
152 
153 	type = (stat->mode & S_IFMT);
154 
155 	*p++ = htonl(nfs_ftypes[type >> 12]);
156 	*p++ = htonl((u32) stat->mode);
157 	*p++ = htonl((u32) stat->nlink);
158 	*p++ = htonl((u32) from_kuid(&init_user_ns, stat->uid));
159 	*p++ = htonl((u32) from_kgid(&init_user_ns, stat->gid));
160 
161 	if (S_ISLNK(type) && stat->size > NFS_MAXPATHLEN) {
162 		*p++ = htonl(NFS_MAXPATHLEN);
163 	} else {
164 		*p++ = htonl((u32) stat->size);
165 	}
166 	*p++ = htonl((u32) stat->blksize);
167 	if (S_ISCHR(type) || S_ISBLK(type))
168 		*p++ = htonl(new_encode_dev(stat->rdev));
169 	else
170 		*p++ = htonl(0xffffffff);
171 	*p++ = htonl((u32) stat->blocks);
172 	switch (fsid_source(fhp)) {
173 	default:
174 	case FSIDSOURCE_DEV:
175 		*p++ = htonl(new_encode_dev(stat->dev));
176 		break;
177 	case FSIDSOURCE_FSID:
178 		*p++ = htonl((u32) fhp->fh_export->ex_fsid);
179 		break;
180 	case FSIDSOURCE_UUID:
181 		f = ((u32*)fhp->fh_export->ex_uuid)[0];
182 		f ^= ((u32*)fhp->fh_export->ex_uuid)[1];
183 		f ^= ((u32*)fhp->fh_export->ex_uuid)[2];
184 		f ^= ((u32*)fhp->fh_export->ex_uuid)[3];
185 		*p++ = htonl(f);
186 		break;
187 	}
188 	*p++ = htonl((u32) stat->ino);
189 	*p++ = htonl((u32) stat->atime.tv_sec);
190 	*p++ = htonl(stat->atime.tv_nsec ? stat->atime.tv_nsec / 1000 : 0);
191 	time = stat->mtime;
192 	lease_get_mtime(d_inode(dentry), &time);
193 	*p++ = htonl((u32) time.tv_sec);
194 	*p++ = htonl(time.tv_nsec ? time.tv_nsec / 1000 : 0);
195 	*p++ = htonl((u32) stat->ctime.tv_sec);
196 	*p++ = htonl(stat->ctime.tv_nsec ? stat->ctime.tv_nsec / 1000 : 0);
197 
198 	return p;
199 }
200 
201 /* Helper function for NFSv2 ACL code */
202 __be32 *nfs2svc_encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp, struct kstat *stat)
203 {
204 	return encode_fattr(rqstp, p, fhp, stat);
205 }
206 
207 /*
208  * XDR decode functions
209  */
210 int
211 nfssvc_decode_void(struct svc_rqst *rqstp, __be32 *p)
212 {
213 	return xdr_argsize_check(rqstp, p);
214 }
215 
216 int
217 nfssvc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p)
218 {
219 	struct nfsd_fhandle *args = rqstp->rq_argp;
220 
221 	p = decode_fh(p, &args->fh);
222 	if (!p)
223 		return 0;
224 	return xdr_argsize_check(rqstp, p);
225 }
226 
227 int
228 nfssvc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p)
229 {
230 	struct nfsd_sattrargs *args = rqstp->rq_argp;
231 
232 	p = decode_fh(p, &args->fh);
233 	if (!p)
234 		return 0;
235 	p = decode_sattr(p, &args->attrs);
236 
237 	return xdr_argsize_check(rqstp, p);
238 }
239 
240 int
241 nfssvc_decode_diropargs(struct svc_rqst *rqstp, __be32 *p)
242 {
243 	struct nfsd_diropargs *args = rqstp->rq_argp;
244 
245 	if (!(p = decode_fh(p, &args->fh))
246 	 || !(p = decode_filename(p, &args->name, &args->len)))
247 		return 0;
248 
249 	return xdr_argsize_check(rqstp, p);
250 }
251 
252 int
253 nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
254 {
255 	struct nfsd_readargs *args = rqstp->rq_argp;
256 	unsigned int len;
257 	int v;
258 	p = decode_fh(p, &args->fh);
259 	if (!p)
260 		return 0;
261 
262 	args->offset    = ntohl(*p++);
263 	len = args->count     = ntohl(*p++);
264 	p++; /* totalcount - unused */
265 
266 	len = min_t(unsigned int, len, NFSSVC_MAXBLKSIZE_V2);
267 
268 	/* set up somewhere to store response.
269 	 * We take pages, put them on reslist and include in iovec
270 	 */
271 	v=0;
272 	while (len > 0) {
273 		struct page *p = *(rqstp->rq_next_page++);
274 
275 		rqstp->rq_vec[v].iov_base = page_address(p);
276 		rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
277 		len -= rqstp->rq_vec[v].iov_len;
278 		v++;
279 	}
280 	args->vlen = v;
281 	return xdr_argsize_check(rqstp, p);
282 }
283 
284 int
285 nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
286 {
287 	struct nfsd_writeargs *args = rqstp->rq_argp;
288 	unsigned int len, hdr, dlen;
289 	struct kvec *head = rqstp->rq_arg.head;
290 	int v;
291 
292 	p = decode_fh(p, &args->fh);
293 	if (!p)
294 		return 0;
295 
296 	p++;				/* beginoffset */
297 	args->offset = ntohl(*p++);	/* offset */
298 	p++;				/* totalcount */
299 	len = args->len = ntohl(*p++);
300 	/*
301 	 * The protocol specifies a maximum of 8192 bytes.
302 	 */
303 	if (len > NFSSVC_MAXBLKSIZE_V2)
304 		return 0;
305 
306 	/*
307 	 * Check to make sure that we got the right number of
308 	 * bytes.
309 	 */
310 	hdr = (void*)p - head->iov_base;
311 	if (hdr > head->iov_len)
312 		return 0;
313 	dlen = head->iov_len + rqstp->rq_arg.page_len - hdr;
314 
315 	/*
316 	 * Round the length of the data which was specified up to
317 	 * the next multiple of XDR units and then compare that
318 	 * against the length which was actually received.
319 	 * Note that when RPCSEC/GSS (for example) is used, the
320 	 * data buffer can be padded so dlen might be larger
321 	 * than required.  It must never be smaller.
322 	 */
323 	if (dlen < XDR_QUADLEN(len)*4)
324 		return 0;
325 
326 	rqstp->rq_vec[0].iov_base = (void*)p;
327 	rqstp->rq_vec[0].iov_len = head->iov_len - hdr;
328 	v = 0;
329 	while (len > rqstp->rq_vec[v].iov_len) {
330 		len -= rqstp->rq_vec[v].iov_len;
331 		v++;
332 		rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_pages[v]);
333 		rqstp->rq_vec[v].iov_len = PAGE_SIZE;
334 	}
335 	rqstp->rq_vec[v].iov_len = len;
336 	args->vlen = v + 1;
337 	return 1;
338 }
339 
340 int
341 nfssvc_decode_createargs(struct svc_rqst *rqstp, __be32 *p)
342 {
343 	struct nfsd_createargs *args = rqstp->rq_argp;
344 
345 	if (   !(p = decode_fh(p, &args->fh))
346 	    || !(p = decode_filename(p, &args->name, &args->len)))
347 		return 0;
348 	p = decode_sattr(p, &args->attrs);
349 
350 	return xdr_argsize_check(rqstp, p);
351 }
352 
353 int
354 nfssvc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p)
355 {
356 	struct nfsd_renameargs *args = rqstp->rq_argp;
357 
358 	if (!(p = decode_fh(p, &args->ffh))
359 	 || !(p = decode_filename(p, &args->fname, &args->flen))
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_readlinkargs(struct svc_rqst *rqstp, __be32 *p)
369 {
370 	struct nfsd_readlinkargs *args = rqstp->rq_argp;
371 
372 	p = decode_fh(p, &args->fh);
373 	if (!p)
374 		return 0;
375 	args->buffer = page_address(*(rqstp->rq_next_page++));
376 
377 	return xdr_argsize_check(rqstp, p);
378 }
379 
380 int
381 nfssvc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
382 {
383 	struct nfsd_linkargs *args = rqstp->rq_argp;
384 
385 	if (!(p = decode_fh(p, &args->ffh))
386 	 || !(p = decode_fh(p, &args->tfh))
387 	 || !(p = decode_filename(p, &args->tname, &args->tlen)))
388 		return 0;
389 
390 	return xdr_argsize_check(rqstp, p);
391 }
392 
393 int
394 nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
395 {
396 	struct nfsd_symlinkargs *args = rqstp->rq_argp;
397 
398 	if (   !(p = decode_fh(p, &args->ffh))
399 	    || !(p = decode_filename(p, &args->fname, &args->flen))
400 	    || !(p = decode_pathname(p, &args->tname, &args->tlen)))
401 		return 0;
402 	p = decode_sattr(p, &args->attrs);
403 
404 	return xdr_argsize_check(rqstp, p);
405 }
406 
407 int
408 nfssvc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
409 {
410 	struct nfsd_readdirargs *args = rqstp->rq_argp;
411 
412 	p = decode_fh(p, &args->fh);
413 	if (!p)
414 		return 0;
415 	args->cookie = ntohl(*p++);
416 	args->count  = ntohl(*p++);
417 	args->count  = min_t(u32, args->count, PAGE_SIZE);
418 	args->buffer = page_address(*(rqstp->rq_next_page++));
419 
420 	return xdr_argsize_check(rqstp, p);
421 }
422 
423 /*
424  * XDR encode functions
425  */
426 int
427 nfssvc_encode_void(struct svc_rqst *rqstp, __be32 *p)
428 {
429 	return xdr_ressize_check(rqstp, p);
430 }
431 
432 int
433 nfssvc_encode_attrstat(struct svc_rqst *rqstp, __be32 *p)
434 {
435 	struct nfsd_attrstat *resp = rqstp->rq_resp;
436 
437 	p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
438 	return xdr_ressize_check(rqstp, p);
439 }
440 
441 int
442 nfssvc_encode_diropres(struct svc_rqst *rqstp, __be32 *p)
443 {
444 	struct nfsd_diropres *resp = rqstp->rq_resp;
445 
446 	p = encode_fh(p, &resp->fh);
447 	p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
448 	return xdr_ressize_check(rqstp, p);
449 }
450 
451 int
452 nfssvc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
453 {
454 	struct nfsd_readlinkres *resp = rqstp->rq_resp;
455 
456 	*p++ = htonl(resp->len);
457 	xdr_ressize_check(rqstp, p);
458 	rqstp->rq_res.page_len = resp->len;
459 	if (resp->len & 3) {
460 		/* need to pad the tail */
461 		rqstp->rq_res.tail[0].iov_base = p;
462 		*p = 0;
463 		rqstp->rq_res.tail[0].iov_len = 4 - (resp->len&3);
464 	}
465 	return 1;
466 }
467 
468 int
469 nfssvc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
470 {
471 	struct nfsd_readres *resp = rqstp->rq_resp;
472 
473 	p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
474 	*p++ = htonl(resp->count);
475 	xdr_ressize_check(rqstp, p);
476 
477 	/* now update rqstp->rq_res to reflect data as well */
478 	rqstp->rq_res.page_len = resp->count;
479 	if (resp->count & 3) {
480 		/* need to pad the tail */
481 		rqstp->rq_res.tail[0].iov_base = p;
482 		*p = 0;
483 		rqstp->rq_res.tail[0].iov_len = 4 - (resp->count&3);
484 	}
485 	return 1;
486 }
487 
488 int
489 nfssvc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
490 {
491 	struct nfsd_readdirres *resp = rqstp->rq_resp;
492 
493 	xdr_ressize_check(rqstp, p);
494 	p = resp->buffer;
495 	*p++ = 0;			/* no more entries */
496 	*p++ = htonl((resp->common.err == nfserr_eof));
497 	rqstp->rq_res.page_len = (((unsigned long)p-1) & ~PAGE_MASK)+1;
498 
499 	return 1;
500 }
501 
502 int
503 nfssvc_encode_statfsres(struct svc_rqst *rqstp, __be32 *p)
504 {
505 	struct nfsd_statfsres *resp = rqstp->rq_resp;
506 	struct kstatfs	*stat = &resp->stats;
507 
508 	*p++ = htonl(NFSSVC_MAXBLKSIZE_V2);	/* max transfer size */
509 	*p++ = htonl(stat->f_bsize);
510 	*p++ = htonl(stat->f_blocks);
511 	*p++ = htonl(stat->f_bfree);
512 	*p++ = htonl(stat->f_bavail);
513 	return xdr_ressize_check(rqstp, p);
514 }
515 
516 int
517 nfssvc_encode_entry(void *ccdv, const char *name,
518 		    int namlen, loff_t offset, u64 ino, unsigned int d_type)
519 {
520 	struct readdir_cd *ccd = ccdv;
521 	struct nfsd_readdirres *cd = container_of(ccd, struct nfsd_readdirres, common);
522 	__be32	*p = cd->buffer;
523 	int	buflen, slen;
524 
525 	/*
526 	dprintk("nfsd: entry(%.*s off %ld ino %ld)\n",
527 			namlen, name, offset, ino);
528 	 */
529 
530 	if (offset > ~((u32) 0)) {
531 		cd->common.err = nfserr_fbig;
532 		return -EINVAL;
533 	}
534 	if (cd->offset)
535 		*cd->offset = htonl(offset);
536 
537 	/* truncate filename */
538 	namlen = min(namlen, NFS2_MAXNAMLEN);
539 	slen = XDR_QUADLEN(namlen);
540 
541 	if ((buflen = cd->buflen - slen - 4) < 0) {
542 		cd->common.err = nfserr_toosmall;
543 		return -EINVAL;
544 	}
545 	if (ino > ~((u32) 0)) {
546 		cd->common.err = nfserr_fbig;
547 		return -EINVAL;
548 	}
549 	*p++ = xdr_one;				/* mark entry present */
550 	*p++ = htonl((u32) ino);		/* file id */
551 	p    = xdr_encode_array(p, name, namlen);/* name length & name */
552 	cd->offset = p;			/* remember pointer */
553 	*p++ = htonl(~0U);		/* offset of next entry */
554 
555 	cd->buflen = buflen;
556 	cd->buffer = p;
557 	cd->common.err = nfs_ok;
558 	return 0;
559 }
560 
561 /*
562  * XDR release functions
563  */
564 void
565 nfssvc_release_fhandle(struct svc_rqst *rqstp)
566 {
567 	struct nfsd_fhandle *resp = rqstp->rq_resp;
568 
569 	fh_put(&resp->fh);
570 }
571