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1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * net/9p/protocol.c
4  *
5  * 9P Protocol Support Code
6  *
7  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
8  *
9  *  Base on code from Anthony Liguori <aliguori@us.ibm.com>
10  *  Copyright (C) 2008 by IBM, Corp.
11  */
12 
13 #include <linux/module.h>
14 #include <linux/errno.h>
15 #include <linux/kernel.h>
16 #include <linux/uaccess.h>
17 #include <linux/slab.h>
18 #include <linux/sched.h>
19 #include <linux/stddef.h>
20 #include <linux/types.h>
21 #include <linux/uio.h>
22 #include <net/9p/9p.h>
23 #include <net/9p/client.h>
24 #include "protocol.h"
25 
26 #include <trace/events/9p.h>
27 
28 static int
29 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
30 
p9stat_free(struct p9_wstat * stbuf)31 void p9stat_free(struct p9_wstat *stbuf)
32 {
33 	kfree(stbuf->name);
34 	stbuf->name = NULL;
35 	kfree(stbuf->uid);
36 	stbuf->uid = NULL;
37 	kfree(stbuf->gid);
38 	stbuf->gid = NULL;
39 	kfree(stbuf->muid);
40 	stbuf->muid = NULL;
41 	kfree(stbuf->extension);
42 	stbuf->extension = NULL;
43 }
44 EXPORT_SYMBOL(p9stat_free);
45 
pdu_read(struct p9_fcall * pdu,void * data,size_t size)46 size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
47 {
48 	size_t len = min(pdu->size - pdu->offset, size);
49 	memcpy(data, &pdu->sdata[pdu->offset], len);
50 	pdu->offset += len;
51 	return size - len;
52 }
53 
pdu_write(struct p9_fcall * pdu,const void * data,size_t size)54 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
55 {
56 	size_t len = min(pdu->capacity - pdu->size, size);
57 	memcpy(&pdu->sdata[pdu->size], data, len);
58 	pdu->size += len;
59 	return size - len;
60 }
61 
62 static size_t
pdu_write_u(struct p9_fcall * pdu,struct iov_iter * from,size_t size)63 pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size)
64 {
65 	size_t len = min(pdu->capacity - pdu->size, size);
66 	struct iov_iter i = *from;
67 	if (!copy_from_iter_full(&pdu->sdata[pdu->size], len, &i))
68 		len = 0;
69 
70 	pdu->size += len;
71 	return size - len;
72 }
73 
74 /*
75 	b - int8_t
76 	w - int16_t
77 	d - int32_t
78 	q - int64_t
79 	s - string
80 	u - numeric uid
81 	g - numeric gid
82 	S - stat
83 	Q - qid
84 	D - data blob (int32_t size followed by void *, results are not freed)
85 	T - array of strings (int16_t count, followed by strings)
86 	R - array of qids (int16_t count, followed by qids)
87 	A - stat for 9p2000.L (p9_stat_dotl)
88 	? - if optional = 1, continue parsing
89 */
90 
91 static int
p9pdu_vreadf(struct p9_fcall * pdu,int proto_version,const char * fmt,va_list ap)92 p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
93 	va_list ap)
94 {
95 	const char *ptr;
96 	int errcode = 0;
97 
98 	for (ptr = fmt; *ptr; ptr++) {
99 		switch (*ptr) {
100 		case 'b':{
101 				int8_t *val = va_arg(ap, int8_t *);
102 				if (pdu_read(pdu, val, sizeof(*val))) {
103 					errcode = -EFAULT;
104 					break;
105 				}
106 			}
107 			break;
108 		case 'w':{
109 				int16_t *val = va_arg(ap, int16_t *);
110 				__le16 le_val;
111 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
112 					errcode = -EFAULT;
113 					break;
114 				}
115 				*val = le16_to_cpu(le_val);
116 			}
117 			break;
118 		case 'd':{
119 				int32_t *val = va_arg(ap, int32_t *);
120 				__le32 le_val;
121 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
122 					errcode = -EFAULT;
123 					break;
124 				}
125 				*val = le32_to_cpu(le_val);
126 			}
127 			break;
128 		case 'q':{
129 				int64_t *val = va_arg(ap, int64_t *);
130 				__le64 le_val;
131 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
132 					errcode = -EFAULT;
133 					break;
134 				}
135 				*val = le64_to_cpu(le_val);
136 			}
137 			break;
138 		case 's':{
139 				char **sptr = va_arg(ap, char **);
140 				uint16_t len;
141 
142 				errcode = p9pdu_readf(pdu, proto_version,
143 								"w", &len);
144 				if (errcode)
145 					break;
146 
147 				*sptr = kmalloc(len + 1, GFP_NOFS);
148 				if (*sptr == NULL) {
149 					errcode = -ENOMEM;
150 					break;
151 				}
152 				if (pdu_read(pdu, *sptr, len)) {
153 					errcode = -EFAULT;
154 					kfree(*sptr);
155 					*sptr = NULL;
156 				} else
157 					(*sptr)[len] = 0;
158 			}
159 			break;
160 		case 'u': {
161 				kuid_t *uid = va_arg(ap, kuid_t *);
162 				__le32 le_val;
163 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
164 					errcode = -EFAULT;
165 					break;
166 				}
167 				*uid = make_kuid(&init_user_ns,
168 						 le32_to_cpu(le_val));
169 			} break;
170 		case 'g': {
171 				kgid_t *gid = va_arg(ap, kgid_t *);
172 				__le32 le_val;
173 				if (pdu_read(pdu, &le_val, sizeof(le_val))) {
174 					errcode = -EFAULT;
175 					break;
176 				}
177 				*gid = make_kgid(&init_user_ns,
178 						 le32_to_cpu(le_val));
179 			} break;
180 		case 'Q':{
181 				struct p9_qid *qid =
182 				    va_arg(ap, struct p9_qid *);
183 
184 				errcode = p9pdu_readf(pdu, proto_version, "bdq",
185 						      &qid->type, &qid->version,
186 						      &qid->path);
187 			}
188 			break;
189 		case 'S':{
190 				struct p9_wstat *stbuf =
191 				    va_arg(ap, struct p9_wstat *);
192 
193 				memset(stbuf, 0, sizeof(struct p9_wstat));
194 				stbuf->n_uid = stbuf->n_muid = INVALID_UID;
195 				stbuf->n_gid = INVALID_GID;
196 
197 				errcode =
198 				    p9pdu_readf(pdu, proto_version,
199 						"wwdQdddqssss?sugu",
200 						&stbuf->size, &stbuf->type,
201 						&stbuf->dev, &stbuf->qid,
202 						&stbuf->mode, &stbuf->atime,
203 						&stbuf->mtime, &stbuf->length,
204 						&stbuf->name, &stbuf->uid,
205 						&stbuf->gid, &stbuf->muid,
206 						&stbuf->extension,
207 						&stbuf->n_uid, &stbuf->n_gid,
208 						&stbuf->n_muid);
209 				if (errcode)
210 					p9stat_free(stbuf);
211 			}
212 			break;
213 		case 'D':{
214 				uint32_t *count = va_arg(ap, uint32_t *);
215 				void **data = va_arg(ap, void **);
216 
217 				errcode =
218 				    p9pdu_readf(pdu, proto_version, "d", count);
219 				if (!errcode) {
220 					*count =
221 					    min_t(uint32_t, *count,
222 						  pdu->size - pdu->offset);
223 					*data = &pdu->sdata[pdu->offset];
224 				}
225 			}
226 			break;
227 		case 'T':{
228 				uint16_t *nwname = va_arg(ap, uint16_t *);
229 				char ***wnames = va_arg(ap, char ***);
230 
231 				*wnames = NULL;
232 
233 				errcode = p9pdu_readf(pdu, proto_version,
234 								"w", nwname);
235 				if (!errcode) {
236 					*wnames =
237 					    kmalloc_array(*nwname,
238 							  sizeof(char *),
239 							  GFP_NOFS);
240 					if (!*wnames)
241 						errcode = -ENOMEM;
242 					else
243 						(*wnames)[0] = NULL;
244 				}
245 
246 				if (!errcode) {
247 					int i;
248 
249 					for (i = 0; i < *nwname; i++) {
250 						errcode =
251 						    p9pdu_readf(pdu,
252 								proto_version,
253 								"s",
254 								&(*wnames)[i]);
255 						if (errcode) {
256 							(*wnames)[i] = NULL;
257 							break;
258 						}
259 					}
260 				}
261 
262 				if (errcode) {
263 					if (*wnames) {
264 						int i;
265 
266 						for (i = 0; i < *nwname; i++) {
267 							if (!(*wnames)[i])
268 								break;
269 							kfree((*wnames)[i]);
270 						}
271 						kfree(*wnames);
272 						*wnames = NULL;
273 					}
274 				}
275 			}
276 			break;
277 		case 'R':{
278 				uint16_t *nwqid = va_arg(ap, uint16_t *);
279 				struct p9_qid **wqids =
280 				    va_arg(ap, struct p9_qid **);
281 
282 				*wqids = NULL;
283 
284 				errcode =
285 				    p9pdu_readf(pdu, proto_version, "w", nwqid);
286 				if (!errcode) {
287 					*wqids =
288 					    kmalloc_array(*nwqid,
289 							  sizeof(struct p9_qid),
290 							  GFP_NOFS);
291 					if (*wqids == NULL)
292 						errcode = -ENOMEM;
293 				}
294 
295 				if (!errcode) {
296 					int i;
297 
298 					for (i = 0; i < *nwqid; i++) {
299 						errcode =
300 						    p9pdu_readf(pdu,
301 								proto_version,
302 								"Q",
303 								&(*wqids)[i]);
304 						if (errcode)
305 							break;
306 					}
307 				}
308 
309 				if (errcode) {
310 					kfree(*wqids);
311 					*wqids = NULL;
312 				}
313 			}
314 			break;
315 		case 'A': {
316 				struct p9_stat_dotl *stbuf =
317 				    va_arg(ap, struct p9_stat_dotl *);
318 
319 				memset(stbuf, 0, sizeof(struct p9_stat_dotl));
320 				errcode =
321 				    p9pdu_readf(pdu, proto_version,
322 					"qQdugqqqqqqqqqqqqqqq",
323 					&stbuf->st_result_mask,
324 					&stbuf->qid,
325 					&stbuf->st_mode,
326 					&stbuf->st_uid, &stbuf->st_gid,
327 					&stbuf->st_nlink,
328 					&stbuf->st_rdev, &stbuf->st_size,
329 					&stbuf->st_blksize, &stbuf->st_blocks,
330 					&stbuf->st_atime_sec,
331 					&stbuf->st_atime_nsec,
332 					&stbuf->st_mtime_sec,
333 					&stbuf->st_mtime_nsec,
334 					&stbuf->st_ctime_sec,
335 					&stbuf->st_ctime_nsec,
336 					&stbuf->st_btime_sec,
337 					&stbuf->st_btime_nsec,
338 					&stbuf->st_gen,
339 					&stbuf->st_data_version);
340 			}
341 			break;
342 		case '?':
343 			if ((proto_version != p9_proto_2000u) &&
344 				(proto_version != p9_proto_2000L))
345 				return 0;
346 			break;
347 		default:
348 			BUG();
349 			break;
350 		}
351 
352 		if (errcode)
353 			break;
354 	}
355 
356 	return errcode;
357 }
358 
359 int
p9pdu_vwritef(struct p9_fcall * pdu,int proto_version,const char * fmt,va_list ap)360 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
361 	va_list ap)
362 {
363 	const char *ptr;
364 	int errcode = 0;
365 
366 	for (ptr = fmt; *ptr; ptr++) {
367 		switch (*ptr) {
368 		case 'b':{
369 				int8_t val = va_arg(ap, int);
370 				if (pdu_write(pdu, &val, sizeof(val)))
371 					errcode = -EFAULT;
372 			}
373 			break;
374 		case 'w':{
375 				__le16 val = cpu_to_le16(va_arg(ap, int));
376 				if (pdu_write(pdu, &val, sizeof(val)))
377 					errcode = -EFAULT;
378 			}
379 			break;
380 		case 'd':{
381 				__le32 val = cpu_to_le32(va_arg(ap, int32_t));
382 				if (pdu_write(pdu, &val, sizeof(val)))
383 					errcode = -EFAULT;
384 			}
385 			break;
386 		case 'q':{
387 				__le64 val = cpu_to_le64(va_arg(ap, int64_t));
388 				if (pdu_write(pdu, &val, sizeof(val)))
389 					errcode = -EFAULT;
390 			}
391 			break;
392 		case 's':{
393 				const char *sptr = va_arg(ap, const char *);
394 				uint16_t len = 0;
395 				if (sptr)
396 					len = min_t(size_t, strlen(sptr),
397 								USHRT_MAX);
398 
399 				errcode = p9pdu_writef(pdu, proto_version,
400 								"w", len);
401 				if (!errcode && pdu_write(pdu, sptr, len))
402 					errcode = -EFAULT;
403 			}
404 			break;
405 		case 'u': {
406 				kuid_t uid = va_arg(ap, kuid_t);
407 				__le32 val = cpu_to_le32(
408 						from_kuid(&init_user_ns, uid));
409 				if (pdu_write(pdu, &val, sizeof(val)))
410 					errcode = -EFAULT;
411 			} break;
412 		case 'g': {
413 				kgid_t gid = va_arg(ap, kgid_t);
414 				__le32 val = cpu_to_le32(
415 						from_kgid(&init_user_ns, gid));
416 				if (pdu_write(pdu, &val, sizeof(val)))
417 					errcode = -EFAULT;
418 			} break;
419 		case 'Q':{
420 				const struct p9_qid *qid =
421 				    va_arg(ap, const struct p9_qid *);
422 				errcode =
423 				    p9pdu_writef(pdu, proto_version, "bdq",
424 						 qid->type, qid->version,
425 						 qid->path);
426 			} break;
427 		case 'S':{
428 				const struct p9_wstat *stbuf =
429 				    va_arg(ap, const struct p9_wstat *);
430 				errcode =
431 				    p9pdu_writef(pdu, proto_version,
432 						 "wwdQdddqssss?sugu",
433 						 stbuf->size, stbuf->type,
434 						 stbuf->dev, &stbuf->qid,
435 						 stbuf->mode, stbuf->atime,
436 						 stbuf->mtime, stbuf->length,
437 						 stbuf->name, stbuf->uid,
438 						 stbuf->gid, stbuf->muid,
439 						 stbuf->extension, stbuf->n_uid,
440 						 stbuf->n_gid, stbuf->n_muid);
441 			} break;
442 		case 'V':{
443 				uint32_t count = va_arg(ap, uint32_t);
444 				struct iov_iter *from =
445 						va_arg(ap, struct iov_iter *);
446 				errcode = p9pdu_writef(pdu, proto_version, "d",
447 									count);
448 				if (!errcode && pdu_write_u(pdu, from, count))
449 					errcode = -EFAULT;
450 			}
451 			break;
452 		case 'T':{
453 				uint16_t nwname = va_arg(ap, int);
454 				const char **wnames = va_arg(ap, const char **);
455 
456 				errcode = p9pdu_writef(pdu, proto_version, "w",
457 									nwname);
458 				if (!errcode) {
459 					int i;
460 
461 					for (i = 0; i < nwname; i++) {
462 						errcode =
463 						    p9pdu_writef(pdu,
464 								proto_version,
465 								 "s",
466 								 wnames[i]);
467 						if (errcode)
468 							break;
469 					}
470 				}
471 			}
472 			break;
473 		case 'R':{
474 				uint16_t nwqid = va_arg(ap, int);
475 				struct p9_qid *wqids =
476 				    va_arg(ap, struct p9_qid *);
477 
478 				errcode = p9pdu_writef(pdu, proto_version, "w",
479 									nwqid);
480 				if (!errcode) {
481 					int i;
482 
483 					for (i = 0; i < nwqid; i++) {
484 						errcode =
485 						    p9pdu_writef(pdu,
486 								proto_version,
487 								 "Q",
488 								 &wqids[i]);
489 						if (errcode)
490 							break;
491 					}
492 				}
493 			}
494 			break;
495 		case 'I':{
496 				struct p9_iattr_dotl *p9attr = va_arg(ap,
497 							struct p9_iattr_dotl *);
498 
499 				errcode = p9pdu_writef(pdu, proto_version,
500 							"ddugqqqqq",
501 							p9attr->valid,
502 							p9attr->mode,
503 							p9attr->uid,
504 							p9attr->gid,
505 							p9attr->size,
506 							p9attr->atime_sec,
507 							p9attr->atime_nsec,
508 							p9attr->mtime_sec,
509 							p9attr->mtime_nsec);
510 			}
511 			break;
512 		case '?':
513 			if ((proto_version != p9_proto_2000u) &&
514 				(proto_version != p9_proto_2000L))
515 				return 0;
516 			break;
517 		default:
518 			BUG();
519 			break;
520 		}
521 
522 		if (errcode)
523 			break;
524 	}
525 
526 	return errcode;
527 }
528 
p9pdu_readf(struct p9_fcall * pdu,int proto_version,const char * fmt,...)529 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
530 {
531 	va_list ap;
532 	int ret;
533 
534 	va_start(ap, fmt);
535 	ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
536 	va_end(ap);
537 
538 	return ret;
539 }
540 
541 static int
p9pdu_writef(struct p9_fcall * pdu,int proto_version,const char * fmt,...)542 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
543 {
544 	va_list ap;
545 	int ret;
546 
547 	va_start(ap, fmt);
548 	ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
549 	va_end(ap);
550 
551 	return ret;
552 }
553 
p9stat_read(struct p9_client * clnt,char * buf,int len,struct p9_wstat * st)554 int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
555 {
556 	struct p9_fcall fake_pdu;
557 	int ret;
558 
559 	fake_pdu.size = len;
560 	fake_pdu.capacity = len;
561 	fake_pdu.sdata = buf;
562 	fake_pdu.offset = 0;
563 
564 	ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
565 	if (ret) {
566 		p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
567 		trace_9p_protocol_dump(clnt, &fake_pdu);
568 		return ret;
569 	}
570 
571 	return fake_pdu.offset;
572 }
573 EXPORT_SYMBOL(p9stat_read);
574 
p9pdu_prepare(struct p9_fcall * pdu,int16_t tag,int8_t type)575 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
576 {
577 	pdu->id = type;
578 	return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
579 }
580 
p9pdu_finalize(struct p9_client * clnt,struct p9_fcall * pdu)581 int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
582 {
583 	int size = pdu->size;
584 	int err;
585 
586 	pdu->size = 0;
587 	err = p9pdu_writef(pdu, 0, "d", size);
588 	pdu->size = size;
589 
590 	trace_9p_protocol_dump(clnt, pdu);
591 	p9_debug(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n",
592 		 pdu->size, pdu->id, pdu->tag);
593 
594 	return err;
595 }
596 
p9pdu_reset(struct p9_fcall * pdu)597 void p9pdu_reset(struct p9_fcall *pdu)
598 {
599 	pdu->offset = 0;
600 	pdu->size = 0;
601 }
602 
p9dirent_read(struct p9_client * clnt,char * buf,int len,struct p9_dirent * dirent)603 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
604 		  struct p9_dirent *dirent)
605 {
606 	struct p9_fcall fake_pdu;
607 	int ret;
608 	char *nameptr;
609 
610 	fake_pdu.size = len;
611 	fake_pdu.capacity = len;
612 	fake_pdu.sdata = buf;
613 	fake_pdu.offset = 0;
614 
615 	ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
616 			  &dirent->d_off, &dirent->d_type, &nameptr);
617 	if (ret) {
618 		p9_debug(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
619 		trace_9p_protocol_dump(clnt, &fake_pdu);
620 		return ret;
621 	}
622 
623 	ret = strscpy(dirent->d_name, nameptr, sizeof(dirent->d_name));
624 	if (ret < 0) {
625 		p9_debug(P9_DEBUG_ERROR,
626 			 "On the wire dirent name too long: %s\n",
627 			 nameptr);
628 		kfree(nameptr);
629 		return ret;
630 	}
631 	kfree(nameptr);
632 
633 	return fake_pdu.offset;
634 }
635 EXPORT_SYMBOL(p9dirent_read);
636