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
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
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
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
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
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 errcode = p9pdu_readf(pdu, proto_version,
232 "w", nwname);
233 if (!errcode) {
234 *wnames =
235 kmalloc_array(*nwname,
236 sizeof(char *),
237 GFP_NOFS);
238 if (!*wnames)
239 errcode = -ENOMEM;
240 }
241
242 if (!errcode) {
243 int i;
244
245 for (i = 0; i < *nwname; i++) {
246 errcode =
247 p9pdu_readf(pdu,
248 proto_version,
249 "s",
250 &(*wnames)[i]);
251 if (errcode)
252 break;
253 }
254 }
255
256 if (errcode) {
257 if (*wnames) {
258 int i;
259
260 for (i = 0; i < *nwname; i++)
261 kfree((*wnames)[i]);
262 }
263 kfree(*wnames);
264 *wnames = NULL;
265 }
266 }
267 break;
268 case 'R':{
269 uint16_t *nwqid = va_arg(ap, uint16_t *);
270 struct p9_qid **wqids =
271 va_arg(ap, struct p9_qid **);
272
273 *wqids = NULL;
274
275 errcode =
276 p9pdu_readf(pdu, proto_version, "w", nwqid);
277 if (!errcode) {
278 *wqids =
279 kmalloc_array(*nwqid,
280 sizeof(struct p9_qid),
281 GFP_NOFS);
282 if (*wqids == NULL)
283 errcode = -ENOMEM;
284 }
285
286 if (!errcode) {
287 int i;
288
289 for (i = 0; i < *nwqid; i++) {
290 errcode =
291 p9pdu_readf(pdu,
292 proto_version,
293 "Q",
294 &(*wqids)[i]);
295 if (errcode)
296 break;
297 }
298 }
299
300 if (errcode) {
301 kfree(*wqids);
302 *wqids = NULL;
303 }
304 }
305 break;
306 case 'A': {
307 struct p9_stat_dotl *stbuf =
308 va_arg(ap, struct p9_stat_dotl *);
309
310 memset(stbuf, 0, sizeof(struct p9_stat_dotl));
311 errcode =
312 p9pdu_readf(pdu, proto_version,
313 "qQdugqqqqqqqqqqqqqqq",
314 &stbuf->st_result_mask,
315 &stbuf->qid,
316 &stbuf->st_mode,
317 &stbuf->st_uid, &stbuf->st_gid,
318 &stbuf->st_nlink,
319 &stbuf->st_rdev, &stbuf->st_size,
320 &stbuf->st_blksize, &stbuf->st_blocks,
321 &stbuf->st_atime_sec,
322 &stbuf->st_atime_nsec,
323 &stbuf->st_mtime_sec,
324 &stbuf->st_mtime_nsec,
325 &stbuf->st_ctime_sec,
326 &stbuf->st_ctime_nsec,
327 &stbuf->st_btime_sec,
328 &stbuf->st_btime_nsec,
329 &stbuf->st_gen,
330 &stbuf->st_data_version);
331 }
332 break;
333 case '?':
334 if ((proto_version != p9_proto_2000u) &&
335 (proto_version != p9_proto_2000L))
336 return 0;
337 break;
338 default:
339 BUG();
340 break;
341 }
342
343 if (errcode)
344 break;
345 }
346
347 return errcode;
348 }
349
350 int
351 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
352 va_list ap)
353 {
354 const char *ptr;
355 int errcode = 0;
356
357 for (ptr = fmt; *ptr; ptr++) {
358 switch (*ptr) {
359 case 'b':{
360 int8_t val = va_arg(ap, int);
361 if (pdu_write(pdu, &val, sizeof(val)))
362 errcode = -EFAULT;
363 }
364 break;
365 case 'w':{
366 __le16 val = cpu_to_le16(va_arg(ap, int));
367 if (pdu_write(pdu, &val, sizeof(val)))
368 errcode = -EFAULT;
369 }
370 break;
371 case 'd':{
372 __le32 val = cpu_to_le32(va_arg(ap, int32_t));
373 if (pdu_write(pdu, &val, sizeof(val)))
374 errcode = -EFAULT;
375 }
376 break;
377 case 'q':{
378 __le64 val = cpu_to_le64(va_arg(ap, int64_t));
379 if (pdu_write(pdu, &val, sizeof(val)))
380 errcode = -EFAULT;
381 }
382 break;
383 case 's':{
384 const char *sptr = va_arg(ap, const char *);
385 uint16_t len = 0;
386 if (sptr)
387 len = min_t(size_t, strlen(sptr),
388 USHRT_MAX);
389
390 errcode = p9pdu_writef(pdu, proto_version,
391 "w", len);
392 if (!errcode && pdu_write(pdu, sptr, len))
393 errcode = -EFAULT;
394 }
395 break;
396 case 'u': {
397 kuid_t uid = va_arg(ap, kuid_t);
398 __le32 val = cpu_to_le32(
399 from_kuid(&init_user_ns, uid));
400 if (pdu_write(pdu, &val, sizeof(val)))
401 errcode = -EFAULT;
402 } break;
403 case 'g': {
404 kgid_t gid = va_arg(ap, kgid_t);
405 __le32 val = cpu_to_le32(
406 from_kgid(&init_user_ns, gid));
407 if (pdu_write(pdu, &val, sizeof(val)))
408 errcode = -EFAULT;
409 } break;
410 case 'Q':{
411 const struct p9_qid *qid =
412 va_arg(ap, const struct p9_qid *);
413 errcode =
414 p9pdu_writef(pdu, proto_version, "bdq",
415 qid->type, qid->version,
416 qid->path);
417 } break;
418 case 'S':{
419 const struct p9_wstat *stbuf =
420 va_arg(ap, const struct p9_wstat *);
421 errcode =
422 p9pdu_writef(pdu, proto_version,
423 "wwdQdddqssss?sugu",
424 stbuf->size, stbuf->type,
425 stbuf->dev, &stbuf->qid,
426 stbuf->mode, stbuf->atime,
427 stbuf->mtime, stbuf->length,
428 stbuf->name, stbuf->uid,
429 stbuf->gid, stbuf->muid,
430 stbuf->extension, stbuf->n_uid,
431 stbuf->n_gid, stbuf->n_muid);
432 } break;
433 case 'V':{
434 uint32_t count = va_arg(ap, uint32_t);
435 struct iov_iter *from =
436 va_arg(ap, struct iov_iter *);
437 errcode = p9pdu_writef(pdu, proto_version, "d",
438 count);
439 if (!errcode && pdu_write_u(pdu, from, count))
440 errcode = -EFAULT;
441 }
442 break;
443 case 'T':{
444 uint16_t nwname = va_arg(ap, int);
445 const char **wnames = va_arg(ap, const char **);
446
447 errcode = p9pdu_writef(pdu, proto_version, "w",
448 nwname);
449 if (!errcode) {
450 int i;
451
452 for (i = 0; i < nwname; i++) {
453 errcode =
454 p9pdu_writef(pdu,
455 proto_version,
456 "s",
457 wnames[i]);
458 if (errcode)
459 break;
460 }
461 }
462 }
463 break;
464 case 'R':{
465 uint16_t nwqid = va_arg(ap, int);
466 struct p9_qid *wqids =
467 va_arg(ap, struct p9_qid *);
468
469 errcode = p9pdu_writef(pdu, proto_version, "w",
470 nwqid);
471 if (!errcode) {
472 int i;
473
474 for (i = 0; i < nwqid; i++) {
475 errcode =
476 p9pdu_writef(pdu,
477 proto_version,
478 "Q",
479 &wqids[i]);
480 if (errcode)
481 break;
482 }
483 }
484 }
485 break;
486 case 'I':{
487 struct p9_iattr_dotl *p9attr = va_arg(ap,
488 struct p9_iattr_dotl *);
489
490 errcode = p9pdu_writef(pdu, proto_version,
491 "ddugqqqqq",
492 p9attr->valid,
493 p9attr->mode,
494 p9attr->uid,
495 p9attr->gid,
496 p9attr->size,
497 p9attr->atime_sec,
498 p9attr->atime_nsec,
499 p9attr->mtime_sec,
500 p9attr->mtime_nsec);
501 }
502 break;
503 case '?':
504 if ((proto_version != p9_proto_2000u) &&
505 (proto_version != p9_proto_2000L))
506 return 0;
507 break;
508 default:
509 BUG();
510 break;
511 }
512
513 if (errcode)
514 break;
515 }
516
517 return errcode;
518 }
519
520 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
521 {
522 va_list ap;
523 int ret;
524
525 va_start(ap, fmt);
526 ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
527 va_end(ap);
528
529 return ret;
530 }
531
532 static int
533 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
534 {
535 va_list ap;
536 int ret;
537
538 va_start(ap, fmt);
539 ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
540 va_end(ap);
541
542 return ret;
543 }
544
545 int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
546 {
547 struct p9_fcall fake_pdu;
548 int ret;
549
550 fake_pdu.size = len;
551 fake_pdu.capacity = len;
552 fake_pdu.sdata = buf;
553 fake_pdu.offset = 0;
554
555 ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
556 if (ret) {
557 p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
558 trace_9p_protocol_dump(clnt, &fake_pdu);
559 return ret;
560 }
561
562 return fake_pdu.offset;
563 }
564 EXPORT_SYMBOL(p9stat_read);
565
566 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
567 {
568 pdu->id = type;
569 return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
570 }
571
572 int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
573 {
574 int size = pdu->size;
575 int err;
576
577 pdu->size = 0;
578 err = p9pdu_writef(pdu, 0, "d", size);
579 pdu->size = size;
580
581 trace_9p_protocol_dump(clnt, pdu);
582 p9_debug(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n",
583 pdu->size, pdu->id, pdu->tag);
584
585 return err;
586 }
587
588 void p9pdu_reset(struct p9_fcall *pdu)
589 {
590 pdu->offset = 0;
591 pdu->size = 0;
592 }
593
594 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
595 struct p9_dirent *dirent)
596 {
597 struct p9_fcall fake_pdu;
598 int ret;
599 char *nameptr;
600
601 fake_pdu.size = len;
602 fake_pdu.capacity = len;
603 fake_pdu.sdata = buf;
604 fake_pdu.offset = 0;
605
606 ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
607 &dirent->d_off, &dirent->d_type, &nameptr);
608 if (ret) {
609 p9_debug(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
610 trace_9p_protocol_dump(clnt, &fake_pdu);
611 return ret;
612 }
613
614 ret = strscpy(dirent->d_name, nameptr, sizeof(dirent->d_name));
615 if (ret < 0) {
616 p9_debug(P9_DEBUG_ERROR,
617 "On the wire dirent name too long: %s\n",
618 nameptr);
619 kfree(nameptr);
620 return ret;
621 }
622 kfree(nameptr);
623
624 return fake_pdu.offset;
625 }
626 EXPORT_SYMBOL(p9dirent_read);