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