xref: /linux/fs/nfsd/nfsxdr.c (revision b24413180f5600bcb3bb70fbed5cf186b60864bd) 
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 	lease_get_mtime(d_inode(dentry), &time);
192 	*p++ = htonl((u32) time.tv_sec);
193 	*p++ = htonl(time.tv_nsec ? time.tv_nsec / 1000 : 0);
194 	*p++ = htonl((u32) stat->ctime.tv_sec);
195 	*p++ = htonl(stat->ctime.tv_nsec ? stat->ctime.tv_nsec / 1000 : 0);
196 
197 	return p;
198 }
199 
200 /* Helper function for NFSv2 ACL code */
201 __be32 *nfs2svc_encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp, struct kstat *stat)
202 {
203 	return encode_fattr(rqstp, p, fhp, stat);
204 }
205 
206 /*
207  * XDR decode functions
208  */
209 int
210 nfssvc_decode_void(struct svc_rqst *rqstp, __be32 *p)
211 {
212 	return xdr_argsize_check(rqstp, p);
213 }
214 
215 int
216 nfssvc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p)
217 {
218 	struct nfsd_fhandle *args = rqstp->rq_argp;
219 
220 	p = decode_fh(p, &args->fh);
221 	if (!p)
222 		return 0;
223 	return xdr_argsize_check(rqstp, p);
224 }
225 
226 int
227 nfssvc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p)
228 {
229 	struct nfsd_sattrargs *args = rqstp->rq_argp;
230 
231 	p = decode_fh(p, &args->fh);
232 	if (!p)
233 		return 0;
234 	p = decode_sattr(p, &args->attrs);
235 
236 	return xdr_argsize_check(rqstp, p);
237 }
238 
239 int
240 nfssvc_decode_diropargs(struct svc_rqst *rqstp, __be32 *p)
241 {
242 	struct nfsd_diropargs *args = rqstp->rq_argp;
243 
244 	if (!(p = decode_fh(p, &args->fh))
245 	 || !(p = decode_filename(p, &args->name, &args->len)))
246 		return 0;
247 
248 	return xdr_argsize_check(rqstp, p);
249 }
250 
251 int
252 nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
253 {
254 	struct nfsd_readargs *args = rqstp->rq_argp;
255 	unsigned int len;
256 	int v;
257 	p = decode_fh(p, &args->fh);
258 	if (!p)
259 		return 0;
260 
261 	args->offset    = ntohl(*p++);
262 	len = args->count     = ntohl(*p++);
263 	p++; /* totalcount - unused */
264 
265 	len = min_t(unsigned int, len, NFSSVC_MAXBLKSIZE_V2);
266 
267 	/* set up somewhere to store response.
268 	 * We take pages, put them on reslist and include in iovec
269 	 */
270 	v=0;
271 	while (len > 0) {
272 		struct page *p = *(rqstp->rq_next_page++);
273 
274 		rqstp->rq_vec[v].iov_base = page_address(p);
275 		rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
276 		len -= rqstp->rq_vec[v].iov_len;
277 		v++;
278 	}
279 	args->vlen = v;
280 	return xdr_argsize_check(rqstp, p);
281 }
282 
283 int
284 nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
285 {
286 	struct nfsd_writeargs *args = rqstp->rq_argp;
287 	unsigned int len, hdr, dlen;
288 	struct kvec *head = rqstp->rq_arg.head;
289 	int v;
290 
291 	p = decode_fh(p, &args->fh);
292 	if (!p)
293 		return 0;
294 
295 	p++;				/* beginoffset */
296 	args->offset = ntohl(*p++);	/* offset */
297 	p++;				/* totalcount */
298 	len = args->len = ntohl(*p++);
299 	/*
300 	 * The protocol specifies a maximum of 8192 bytes.
301 	 */
302 	if (len > NFSSVC_MAXBLKSIZE_V2)
303 		return 0;
304 
305 	/*
306 	 * Check to make sure that we got the right number of
307 	 * bytes.
308 	 */
309 	hdr = (void*)p - head->iov_base;
310 	if (hdr > head->iov_len)
311 		return 0;
312 	dlen = head->iov_len + rqstp->rq_arg.page_len - hdr;
313 
314 	/*
315 	 * Round the length of the data which was specified up to
316 	 * the next multiple of XDR units and then compare that
317 	 * against the length which was actually received.
318 	 * Note that when RPCSEC/GSS (for example) is used, the
319 	 * data buffer can be padded so dlen might be larger
320 	 * than required.  It must never be smaller.
321 	 */
322 	if (dlen < XDR_QUADLEN(len)*4)
323 		return 0;
324 
325 	rqstp->rq_vec[0].iov_base = (void*)p;
326 	rqstp->rq_vec[0].iov_len = head->iov_len - hdr;
327 	v = 0;
328 	while (len > rqstp->rq_vec[v].iov_len) {
329 		len -= rqstp->rq_vec[v].iov_len;
330 		v++;
331 		rqstp->rq_vec[v].iov_base = page_address(rqstp->rq_pages[v]);
332 		rqstp->rq_vec[v].iov_len = PAGE_SIZE;
333 	}
334 	rqstp->rq_vec[v].iov_len = len;
335 	args->vlen = v + 1;
336 	return 1;
337 }
338 
339 int
340 nfssvc_decode_createargs(struct svc_rqst *rqstp, __be32 *p)
341 {
342 	struct nfsd_createargs *args = rqstp->rq_argp;
343 
344 	if (   !(p = decode_fh(p, &args->fh))
345 	    || !(p = decode_filename(p, &args->name, &args->len)))
346 		return 0;
347 	p = decode_sattr(p, &args->attrs);
348 
349 	return xdr_argsize_check(rqstp, p);
350 }
351 
352 int
353 nfssvc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p)
354 {
355 	struct nfsd_renameargs *args = rqstp->rq_argp;
356 
357 	if (!(p = decode_fh(p, &args->ffh))
358 	 || !(p = decode_filename(p, &args->fname, &args->flen))
359 	 || !(p = decode_fh(p, &args->tfh))
360 	 || !(p = decode_filename(p, &args->tname, &args->tlen)))
361 		return 0;
362 
363 	return xdr_argsize_check(rqstp, p);
364 }
365 
366 int
367 nfssvc_decode_readlinkargs(struct svc_rqst *rqstp, __be32 *p)
368 {
369 	struct nfsd_readlinkargs *args = rqstp->rq_argp;
370 
371 	p = decode_fh(p, &args->fh);
372 	if (!p)
373 		return 0;
374 	args->buffer = page_address(*(rqstp->rq_next_page++));
375 
376 	return xdr_argsize_check(rqstp, p);
377 }
378 
379 int
380 nfssvc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
381 {
382 	struct nfsd_linkargs *args = rqstp->rq_argp;
383 
384 	if (!(p = decode_fh(p, &args->ffh))
385 	 || !(p = decode_fh(p, &args->tfh))
386 	 || !(p = decode_filename(p, &args->tname, &args->tlen)))
387 		return 0;
388 
389 	return xdr_argsize_check(rqstp, p);
390 }
391 
392 int
393 nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
394 {
395 	struct nfsd_symlinkargs *args = rqstp->rq_argp;
396 
397 	if (   !(p = decode_fh(p, &args->ffh))
398 	    || !(p = decode_filename(p, &args->fname, &args->flen))
399 	    || !(p = decode_pathname(p, &args->tname, &args->tlen)))
400 		return 0;
401 	p = decode_sattr(p, &args->attrs);
402 
403 	return xdr_argsize_check(rqstp, p);
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