net/9p/protocol.c

   1 /*
   2  * net/9p/protocol.c
   3  *
   4  * 9P Protocol Support Code
   5  *
   6  *  Copyright (C) 2008 by Eric Van Hensbergen <ericvh@gmail.com>
   7  *
   8  *  Base on code from Anthony Liguori <aliguori@us.ibm.com>
   9  *  Copyright (C) 2008 by IBM, Corp.
  10  *
  11  *  This program is free software; you can redistribute it and/or modify
  12  *  it under the terms of the GNU General Public License version 2
  13  *  as published by the Free Software Foundation.
  14  *
  15  *  This program is distributed in the hope that it will be useful,
  16  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  *  GNU General Public License for more details.
  19  *
  20  *  You should have received a copy of the GNU General Public License
  21  *  along with this program; if not, write to:
  22  *  Free Software Foundation
  23  *  51 Franklin Street, Fifth Floor
  24  *  Boston, MA  02111-1301  USA
  25  *
  26  */
  27
  28 #include <linux/module.h>
  29 #include <linux/errno.h>
  30 #include <linux/kernel.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/slab.h>
  33 #include <linux/sched.h>
  34 #include <linux/stddef.h>
  35 #include <linux/types.h>
  36 #include <linux/uio.h>
  37 #include <net/9p/9p.h>
  38 #include <net/9p/client.h>
  39 #include "protocol.h"
  40
  41 #include <trace/events/9p.h>
  42
  43 static int
  44 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...);
  45
  46 void p9stat_free(struct p9_wstat *stbuf)
  47 {
  48         kfree(stbuf->name);
  49         stbuf->name = NULL;
  50         kfree(stbuf->uid);
  51         stbuf->uid = NULL;
  52         kfree(stbuf->gid);
  53         stbuf->gid = NULL;
  54         kfree(stbuf->muid);
  55         stbuf->muid = NULL;
  56         kfree(stbuf->extension);
  57         stbuf->extension = NULL;
  58 }
  59 EXPORT_SYMBOL(p9stat_free);
  60
  61 size_t pdu_read(struct p9_fcall *pdu, void *data, size_t size)
  62 {
  63         size_t len = min(pdu->size - pdu->offset, size);
  64         memcpy(data, &pdu->sdata[pdu->offset], len);
  65         pdu->offset += len;
  66         return size - len;
  67 }
  68
  69 static size_t pdu_write(struct p9_fcall *pdu, const void *data, size_t size)
  70 {
  71         size_t len = min(pdu->capacity - pdu->size, size);
  72         memcpy(&pdu->sdata[pdu->size], data, len);
  73         pdu->size += len;
  74         return size - len;
  75 }
  76
  77 static size_t
  78 pdu_write_u(struct p9_fcall *pdu, struct iov_iter *from, size_t size)
  79 {
  80         size_t len = min(pdu->capacity - pdu->size, size);
  81         struct iov_iter i = *from;
  82         if (copy_from_iter(&pdu->sdata[pdu->size], len, &i) != len)
  83                 len = 0;
  84
  85         pdu->size += len;
  86         return size - len;
  87 }
  88
  89 /*
  90         b - int8_t
  91         w - int16_t
  92         d - int32_t
  93         q - int64_t
  94         s - string
  95         u - numeric uid
  96         g - numeric gid
  97         S - stat
  98         Q - qid
  99         D - data blob (int32_t size followed by void *, results are not freed)
 100         T - array of strings (int16_t count, followed by strings)
 101         R - array of qids (int16_t count, followed by qids)
 102         A - stat for 9p2000.L (p9_stat_dotl)
 103         ? - if optional = 1, continue parsing
 104 */
 105
 106 static int
 107 p9pdu_vreadf(struct p9_fcall *pdu, int proto_version, const char *fmt,
 108         va_list ap)
 109 {
 110         const char *ptr;
 111         int errcode = 0;
 112
 113         for (ptr = fmt; *ptr; ptr++) {
 114                 switch (*ptr) {
 115                 case 'b':{
 116                                 int8_t *val = va_arg(ap, int8_t *);
 117                                 if (pdu_read(pdu, val, sizeof(*val))) {
 118                                         errcode = -EFAULT;
 119                                         break;
 120                                 }
 121                         }
 122                         break;
 123                 case 'w':{
 124                                 int16_t *val = va_arg(ap, int16_t *);
 125                                 __le16 le_val;
 126                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 127                                         errcode = -EFAULT;
 128                                         break;
 129                                 }
 130                                 *val = le16_to_cpu(le_val);
 131                         }
 132                         break;
 133                 case 'd':{
 134                                 int32_t *val = va_arg(ap, int32_t *);
 135                                 __le32 le_val;
 136                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 137                                         errcode = -EFAULT;
 138                                         break;
 139                                 }
 140                                 *val = le32_to_cpu(le_val);
 141                         }
 142                         break;
 143                 case 'q':{
 144                                 int64_t *val = va_arg(ap, int64_t *);
 145                                 __le64 le_val;
 146                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 147                                         errcode = -EFAULT;
 148                                         break;
 149                                 }
 150                                 *val = le64_to_cpu(le_val);
 151                         }
 152                         break;
 153                 case 's':{
 154                                 char **sptr = va_arg(ap, char **);
 155                                 uint16_t len;
 156
 157                                 errcode = p9pdu_readf(pdu, proto_version,
 158                                                                 "w", &len);
 159                                 if (errcode)
 160                                         break;
 161
 162                                 *sptr = kmalloc(len + 1, GFP_NOFS);
 163                                 if (*sptr == NULL) {
 164                                         errcode = -EFAULT;
 165                                         break;
 166                                 }
 167                                 if (pdu_read(pdu, *sptr, len)) {
 168                                         errcode = -EFAULT;
 169                                         kfree(*sptr);
 170                                         *sptr = NULL;
 171                                 } else
 172                                         (*sptr)[len] = 0;
 173                         }
 174                         break;
 175                 case 'u': {
 176                                 kuid_t *uid = va_arg(ap, kuid_t *);
 177                                 __le32 le_val;
 178                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 179                                         errcode = -EFAULT;
 180                                         break;
 181                                 }
 182                                 *uid = make_kuid(&init_user_ns,
 183                                                  le32_to_cpu(le_val));
 184                         } break;
 185                 case 'g': {
 186                                 kgid_t *gid = va_arg(ap, kgid_t *);
 187                                 __le32 le_val;
 188                                 if (pdu_read(pdu, &le_val, sizeof(le_val))) {
 189                                         errcode = -EFAULT;
 190                                         break;
 191                                 }
 192                                 *gid = make_kgid(&init_user_ns,
 193                                                  le32_to_cpu(le_val));
 194                         } break;
 195                 case 'Q':{
 196                                 struct p9_qid *qid =
 197                                     va_arg(ap, struct p9_qid *);
 198
 199                                 errcode = p9pdu_readf(pdu, proto_version, "bdq",
 200                                                       &qid->type, &qid->version,
 201                                                       &qid->path);
 202                         }
 203                         break;
 204                 case 'S':{
 205                                 struct p9_wstat *stbuf =
 206                                     va_arg(ap, struct p9_wstat *);
 207
 208                                 memset(stbuf, 0, sizeof(struct p9_wstat));
 209                                 stbuf->n_uid = stbuf->n_muid = INVALID_UID;
 210                                 stbuf->n_gid = INVALID_GID;
 211
 212                                 errcode =
 213                                     p9pdu_readf(pdu, proto_version,
 214                                                 "wwdQdddqssss?sugu",
 215                                                 &stbuf->size, &stbuf->type,
 216                                                 &stbuf->dev, &stbuf->qid,
 217                                                 &stbuf->mode, &stbuf->atime,
 218                                                 &stbuf->mtime, &stbuf->length,
 219                                                 &stbuf->name, &stbuf->uid,
 220                                                 &stbuf->gid, &stbuf->muid,
 221                                                 &stbuf->extension,
 222                                                 &stbuf->n_uid, &stbuf->n_gid,
 223                                                 &stbuf->n_muid);
 224                                 if (errcode)
 225                                         p9stat_free(stbuf);
 226                         }
 227                         break;
 228                 case 'D':{
 229                                 uint32_t *count = va_arg(ap, uint32_t *);
 230                                 void **data = va_arg(ap, void **);
 231
 232                                 errcode =
 233                                     p9pdu_readf(pdu, proto_version, "d", count);
 234                                 if (!errcode) {
 235                                         *count =
 236                                             min_t(uint32_t, *count,
 237                                                   pdu->size - pdu->offset);
 238                                         *data = &pdu->sdata[pdu->offset];
 239                                 }
 240                         }
 241                         break;
 242                 case 'T':{
 243                                 uint16_t *nwname = va_arg(ap, uint16_t *);
 244                                 char ***wnames = va_arg(ap, char ***);
 245
 246                                 errcode = p9pdu_readf(pdu, proto_version,
 247                                                                 "w", nwname);
 248                                 if (!errcode) {
 249                                         *wnames =
 250                                             kmalloc(sizeof(char *) * *nwname,
 251                                                     GFP_NOFS);
 252                                         if (!*wnames)
 253                                                 errcode = -ENOMEM;
 254                                 }
 255
 256                                 if (!errcode) {
 257                                         int i;
 258
 259                                         for (i = 0; i < *nwname; i++) {
 260                                                 errcode =
 261                                                     p9pdu_readf(pdu,
 262                                                                 proto_version,
 263                                                                 "s",
 264                                                                 &(*wnames)[i]);
 265                                                 if (errcode)
 266                                                         break;
 267                                         }
 268                                 }
 269
 270                                 if (errcode) {
 271                                         if (*wnames) {
 272                                                 int i;
 273
 274                                                 for (i = 0; i < *nwname; i++)
 275                                                         kfree((*wnames)[i]);
 276                                         }
 277                                         kfree(*wnames);
 278                                         *wnames = NULL;
 279                                 }
 280                         }
 281                         break;
 282                 case 'R':{
 283                                 uint16_t *nwqid = va_arg(ap, uint16_t *);
 284                                 struct p9_qid **wqids =
 285                                     va_arg(ap, struct p9_qid **);
 286
 287                                 *wqids = NULL;
 288
 289                                 errcode =
 290                                     p9pdu_readf(pdu, proto_version, "w", nwqid);
 291                                 if (!errcode) {
 292                                         *wqids =
 293                                             kmalloc(*nwqid *
 294                                                     sizeof(struct p9_qid),
 295                                                     GFP_NOFS);
 296                                         if (*wqids == NULL)
 297                                                 errcode = -ENOMEM;
 298                                 }
 299
 300                                 if (!errcode) {
 301                                         int i;
 302
 303                                         for (i = 0; i < *nwqid; i++) {
 304                                                 errcode =
 305                                                     p9pdu_readf(pdu,
 306                                                                 proto_version,
 307                                                                 "Q",
 308                                                                 &(*wqids)[i]);
 309                                                 if (errcode)
 310                                                         break;
 311                                         }
 312                                 }
 313
 314                                 if (errcode) {
 315                                         kfree(*wqids);
 316                                         *wqids = NULL;
 317                                 }
 318                         }
 319                         break;
 320                 case 'A': {
 321                                 struct p9_stat_dotl *stbuf =
 322                                     va_arg(ap, struct p9_stat_dotl *);
 323
 324                                 memset(stbuf, 0, sizeof(struct p9_stat_dotl));
 325                                 errcode =
 326                                     p9pdu_readf(pdu, proto_version,
 327                                         "qQdugqqqqqqqqqqqqqqq",
 328                                         &stbuf->st_result_mask,
 329                                         &stbuf->qid,
 330                                         &stbuf->st_mode,
 331                                         &stbuf->st_uid, &stbuf->st_gid,
 332                                         &stbuf->st_nlink,
 333                                         &stbuf->st_rdev, &stbuf->st_size,
 334                                         &stbuf->st_blksize, &stbuf->st_blocks,
 335                                         &stbuf->st_atime_sec,
 336                                         &stbuf->st_atime_nsec,
 337                                         &stbuf->st_mtime_sec,
 338                                         &stbuf->st_mtime_nsec,
 339                                         &stbuf->st_ctime_sec,
 340                                         &stbuf->st_ctime_nsec,
 341                                         &stbuf->st_btime_sec,
 342                                         &stbuf->st_btime_nsec,
 343                                         &stbuf->st_gen,
 344                                         &stbuf->st_data_version);
 345                         }
 346                         break;
 347                 case '?':
 348                         if ((proto_version != p9_proto_2000u) &&
 349                                 (proto_version != p9_proto_2000L))
 350                                 return 0;
 351                         break;
 352                 default:
 353                         BUG();
 354                         break;
 355                 }
 356
 357                 if (errcode)
 358                         break;
 359         }
 360
 361         return errcode;
 362 }
 363
 364 int
 365 p9pdu_vwritef(struct p9_fcall *pdu, int proto_version, const char *fmt,
 366         va_list ap)
 367 {
 368         const char *ptr;
 369         int errcode = 0;
 370
 371         for (ptr = fmt; *ptr; ptr++) {
 372                 switch (*ptr) {
 373                 case 'b':{
 374                                 int8_t val = va_arg(ap, int);
 375                                 if (pdu_write(pdu, &val, sizeof(val)))
 376                                         errcode = -EFAULT;
 377                         }
 378                         break;
 379                 case 'w':{
 380                                 __le16 val = cpu_to_le16(va_arg(ap, int));
 381                                 if (pdu_write(pdu, &val, sizeof(val)))
 382                                         errcode = -EFAULT;
 383                         }
 384                         break;
 385                 case 'd':{
 386                                 __le32 val = cpu_to_le32(va_arg(ap, int32_t));
 387                                 if (pdu_write(pdu, &val, sizeof(val)))
 388                                         errcode = -EFAULT;
 389                         }
 390                         break;
 391                 case 'q':{
 392                                 __le64 val = cpu_to_le64(va_arg(ap, int64_t));
 393                                 if (pdu_write(pdu, &val, sizeof(val)))
 394                                         errcode = -EFAULT;
 395                         }
 396                         break;
 397                 case 's':{
 398                                 const char *sptr = va_arg(ap, const char *);
 399                                 uint16_t len = 0;
 400                                 if (sptr)
 401                                         len = min_t(size_t, strlen(sptr),
 402                                                                 USHRT_MAX);
 403
 404                                 errcode = p9pdu_writef(pdu, proto_version,
 405                                                                 "w", len);
 406                                 if (!errcode && pdu_write(pdu, sptr, len))
 407                                         errcode = -EFAULT;
 408                         }
 409                         break;
 410                 case 'u': {
 411                                 kuid_t uid = va_arg(ap, kuid_t);
 412                                 __le32 val = cpu_to_le32(
 413                                                 from_kuid(&init_user_ns, uid));
 414                                 if (pdu_write(pdu, &val, sizeof(val)))
 415                                         errcode = -EFAULT;
 416                         } break;
 417                 case 'g': {
 418                                 kgid_t gid = va_arg(ap, kgid_t);
 419                                 __le32 val = cpu_to_le32(
 420                                                 from_kgid(&init_user_ns, gid));
 421                                 if (pdu_write(pdu, &val, sizeof(val)))
 422                                         errcode = -EFAULT;
 423                         } break;
 424                 case 'Q':{
 425                                 const struct p9_qid *qid =
 426                                     va_arg(ap, const struct p9_qid *);
 427                                 errcode =
 428                                     p9pdu_writef(pdu, proto_version, "bdq",
 429                                                  qid->type, qid->version,
 430                                                  qid->path);
 431                         } break;
 432                 case 'S':{
 433                                 const struct p9_wstat *stbuf =
 434                                     va_arg(ap, const struct p9_wstat *);
 435                                 errcode =
 436                                     p9pdu_writef(pdu, proto_version,
 437                                                  "wwdQdddqssss?sugu",
 438                                                  stbuf->size, stbuf->type,
 439                                                  stbuf->dev, &stbuf->qid,
 440                                                  stbuf->mode, stbuf->atime,
 441                                                  stbuf->mtime, stbuf->length,
 442                                                  stbuf->name, stbuf->uid,
 443                                                  stbuf->gid, stbuf->muid,
 444                                                  stbuf->extension, stbuf->n_uid,
 445                                                  stbuf->n_gid, stbuf->n_muid);
 446                         } break;
 447                 case 'V':{
 448                                 uint32_t count = va_arg(ap, uint32_t);
 449                                 struct iov_iter *from =
 450                                                 va_arg(ap, struct iov_iter *);
 451                                 errcode = p9pdu_writef(pdu, proto_version, "d",
 452                                                                         count);
 453                                 if (!errcode && pdu_write_u(pdu, from, count))
 454                                         errcode = -EFAULT;
 455                         }
 456                         break;
 457                 case 'T':{
 458                                 uint16_t nwname = va_arg(ap, int);
 459                                 const char **wnames = va_arg(ap, const char **);
 460
 461                                 errcode = p9pdu_writef(pdu, proto_version, "w",
 462                                                                         nwname);
 463                                 if (!errcode) {
 464                                         int i;
 465
 466                                         for (i = 0; i < nwname; i++) {
 467                                                 errcode =
 468                                                     p9pdu_writef(pdu,
 469                                                                 proto_version,
 470                                                                  "s",
 471                                                                  wnames[i]);
 472                                                 if (errcode)
 473                                                         break;
 474                                         }
 475                                 }
 476                         }
 477                         break;
 478                 case 'R':{
 479                                 uint16_t nwqid = va_arg(ap, int);
 480                                 struct p9_qid *wqids =
 481                                     va_arg(ap, struct p9_qid *);
 482
 483                                 errcode = p9pdu_writef(pdu, proto_version, "w",
 484                                                                         nwqid);
 485                                 if (!errcode) {
 486                                         int i;
 487
 488                                         for (i = 0; i < nwqid; i++) {
 489                                                 errcode =
 490                                                     p9pdu_writef(pdu,
 491                                                                 proto_version,
 492                                                                  "Q",
 493                                                                  &wqids[i]);
 494                                                 if (errcode)
 495                                                         break;
 496                                         }
 497                                 }
 498                         }
 499                         break;
 500                 case 'I':{
 501                                 struct p9_iattr_dotl *p9attr = va_arg(ap,
 502                                                         struct p9_iattr_dotl *);
 503
 504                                 errcode = p9pdu_writef(pdu, proto_version,
 505                                                         "ddugqqqqq",
 506                                                         p9attr->valid,
 507                                                         p9attr->mode,
 508                                                         p9attr->uid,
 509                                                         p9attr->gid,
 510                                                         p9attr->size,
 511                                                         p9attr->atime_sec,
 512                                                         p9attr->atime_nsec,
 513                                                         p9attr->mtime_sec,
 514                                                         p9attr->mtime_nsec);
 515                         }
 516                         break;
 517                 case '?':
 518                         if ((proto_version != p9_proto_2000u) &&
 519                                 (proto_version != p9_proto_2000L))
 520                                 return 0;
 521                         break;
 522                 default:
 523                         BUG();
 524                         break;
 525                 }
 526
 527                 if (errcode)
 528                         break;
 529         }
 530
 531         return errcode;
 532 }
 533
 534 int p9pdu_readf(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 535 {
 536         va_list ap;
 537         int ret;
 538
 539         va_start(ap, fmt);
 540         ret = p9pdu_vreadf(pdu, proto_version, fmt, ap);
 541         va_end(ap);
 542
 543         return ret;
 544 }
 545
 546 static int
 547 p9pdu_writef(struct p9_fcall *pdu, int proto_version, const char *fmt, ...)
 548 {
 549         va_list ap;
 550         int ret;
 551
 552         va_start(ap, fmt);
 553         ret = p9pdu_vwritef(pdu, proto_version, fmt, ap);
 554         va_end(ap);
 555
 556         return ret;
 557 }
 558
 559 int p9stat_read(struct p9_client *clnt, char *buf, int len, struct p9_wstat *st)
 560 {
 561         struct p9_fcall fake_pdu;
 562         int ret;
 563
 564         fake_pdu.size = len;
 565         fake_pdu.capacity = len;
 566         fake_pdu.sdata = buf;
 567         fake_pdu.offset = 0;
 568
 569         ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "S", st);
 570         if (ret) {
 571                 p9_debug(P9_DEBUG_9P, "<<< p9stat_read failed: %d\n", ret);
 572                 trace_9p_protocol_dump(clnt, &fake_pdu);
 573                 return ret;
 574         }
 575
 576         return fake_pdu.offset;
 577 }
 578 EXPORT_SYMBOL(p9stat_read);
 579
 580 int p9pdu_prepare(struct p9_fcall *pdu, int16_t tag, int8_t type)
 581 {
 582         pdu->id = type;
 583         return p9pdu_writef(pdu, 0, "dbw", 0, type, tag);
 584 }
 585
 586 int p9pdu_finalize(struct p9_client *clnt, struct p9_fcall *pdu)
 587 {
 588         int size = pdu->size;
 589         int err;
 590
 591         pdu->size = 0;
 592         err = p9pdu_writef(pdu, 0, "d", size);
 593         pdu->size = size;
 594
 595         trace_9p_protocol_dump(clnt, pdu);
 596         p9_debug(P9_DEBUG_9P, ">>> size=%d type: %d tag: %d\n",
 597                  pdu->size, pdu->id, pdu->tag);
 598
 599         return err;
 600 }
 601
 602 void p9pdu_reset(struct p9_fcall *pdu)
 603 {
 604         pdu->offset = 0;
 605         pdu->size = 0;
 606 }
 607
 608 int p9dirent_read(struct p9_client *clnt, char *buf, int len,
 609                   struct p9_dirent *dirent)
 610 {
 611         struct p9_fcall fake_pdu;
 612         int ret;
 613         char *nameptr;
 614
 615         fake_pdu.size = len;
 616         fake_pdu.capacity = len;
 617         fake_pdu.sdata = buf;
 618         fake_pdu.offset = 0;
 619
 620         ret = p9pdu_readf(&fake_pdu, clnt->proto_version, "Qqbs", &dirent->qid,
 621                           &dirent->d_off, &dirent->d_type, &nameptr);
 622         if (ret) {
 623                 p9_debug(P9_DEBUG_9P, "<<< p9dirent_read failed: %d\n", ret);
 624                 trace_9p_protocol_dump(clnt, &fake_pdu);
 625                 return ret;
 626         }
 627
 628         ret = strscpy(dirent->d_name, nameptr, sizeof(dirent->d_name));
 629         if (ret < 0) {
 630                 p9_debug(P9_DEBUG_ERROR,
 631                          "On the wire dirent name too long: %s\n",
 632                          nameptr);
 633                 kfree(nameptr);
 634                 return ret;
 635         }
 636         kfree(nameptr);
 637
 638         return fake_pdu.offset;
 639 }
 640 EXPORT_SYMBOL(p9dirent_read);