fs/nfsd/nfsxdr.c

   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_sattr(__be32 *p, struct iattr *iap, struct user_namespace *userns)
  75 {
  76         u32     tmp, tmp1;
  77
  78         iap->ia_valid = 0;
  79
  80         /* Sun client bug compatibility check: some sun clients seem to
  81          * put 0xffff in the mode field when they mean 0xffffffff.
  82          * Quoting the 4.4BSD nfs server code: Nah nah nah nah na nah.
  83          */
  84         if ((tmp = ntohl(*p++)) != (u32)-1 && tmp != 0xffff) {
  85                 iap->ia_valid |= ATTR_MODE;
  86                 iap->ia_mode = tmp;
  87         }
  88         if ((tmp = ntohl(*p++)) != (u32)-1) {
  89                 iap->ia_uid = make_kuid(userns, tmp);
  90                 if (uid_valid(iap->ia_uid))
  91                         iap->ia_valid |= ATTR_UID;
  92         }
  93         if ((tmp = ntohl(*p++)) != (u32)-1) {
  94                 iap->ia_gid = make_kgid(userns, tmp);
  95                 if (gid_valid(iap->ia_gid))
  96                         iap->ia_valid |= ATTR_GID;
  97         }
  98         if ((tmp = ntohl(*p++)) != (u32)-1) {
  99                 iap->ia_valid |= ATTR_SIZE;
 100                 iap->ia_size = tmp;
 101         }
 102         tmp  = ntohl(*p++); tmp1 = ntohl(*p++);
 103         if (tmp != (u32)-1 && tmp1 != (u32)-1) {
 104                 iap->ia_valid |= ATTR_ATIME | ATTR_ATIME_SET;
 105                 iap->ia_atime.tv_sec = tmp;
 106                 iap->ia_atime.tv_nsec = tmp1 * 1000;
 107         }
 108         tmp  = ntohl(*p++); tmp1 = ntohl(*p++);
 109         if (tmp != (u32)-1 && tmp1 != (u32)-1) {
 110                 iap->ia_valid |= ATTR_MTIME | ATTR_MTIME_SET;
 111                 iap->ia_mtime.tv_sec = tmp;
 112                 iap->ia_mtime.tv_nsec = tmp1 * 1000;
 113                 /*
 114                  * Passing the invalid value useconds=1000000 for mtime
 115                  * is a Sun convention for "set both mtime and atime to
 116                  * current server time".  It's needed to make permissions
 117                  * checks for the "touch" program across v2 mounts to
 118                  * Solaris and Irix boxes work correctly. See description of
 119                  * sattr in section 6.1 of "NFS Illustrated" by
 120                  * Brent Callaghan, Addison-Wesley, ISBN 0-201-32750-5
 121                  */
 122                 if (tmp1 == 1000000)
 123                         iap->ia_valid &= ~(ATTR_ATIME_SET|ATTR_MTIME_SET);
 124         }
 125         return p;
 126 }
 127
 128 static __be32 *
 129 encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp,
 130              struct kstat *stat)
 131 {
 132         struct user_namespace *userns = nfsd_user_namespace(rqstp);
 133         struct dentry   *dentry = fhp->fh_dentry;
 134         int type;
 135         struct timespec64 time;
 136         u32 f;
 137
 138         type = (stat->mode & S_IFMT);
 139
 140         *p++ = htonl(nfs_ftypes[type >> 12]);
 141         *p++ = htonl((u32) stat->mode);
 142         *p++ = htonl((u32) stat->nlink);
 143         *p++ = htonl((u32) from_kuid_munged(userns, stat->uid));
 144         *p++ = htonl((u32) from_kgid_munged(userns, stat->gid));
 145
 146         if (S_ISLNK(type) && stat->size > NFS_MAXPATHLEN) {
 147                 *p++ = htonl(NFS_MAXPATHLEN);
 148         } else {
 149                 *p++ = htonl((u32) stat->size);
 150         }
 151         *p++ = htonl((u32) stat->blksize);
 152         if (S_ISCHR(type) || S_ISBLK(type))
 153                 *p++ = htonl(new_encode_dev(stat->rdev));
 154         else
 155                 *p++ = htonl(0xffffffff);
 156         *p++ = htonl((u32) stat->blocks);
 157         switch (fsid_source(fhp)) {
 158         default:
 159         case FSIDSOURCE_DEV:
 160                 *p++ = htonl(new_encode_dev(stat->dev));
 161                 break;
 162         case FSIDSOURCE_FSID:
 163                 *p++ = htonl((u32) fhp->fh_export->ex_fsid);
 164                 break;
 165         case FSIDSOURCE_UUID:
 166                 f = ((u32*)fhp->fh_export->ex_uuid)[0];
 167                 f ^= ((u32*)fhp->fh_export->ex_uuid)[1];
 168                 f ^= ((u32*)fhp->fh_export->ex_uuid)[2];
 169                 f ^= ((u32*)fhp->fh_export->ex_uuid)[3];
 170                 *p++ = htonl(f);
 171                 break;
 172         }
 173         *p++ = htonl((u32) stat->ino);
 174         *p++ = htonl((u32) stat->atime.tv_sec);
 175         *p++ = htonl(stat->atime.tv_nsec ? stat->atime.tv_nsec / 1000 : 0);
 176         time = stat->mtime;
 177         lease_get_mtime(d_inode(dentry), &time);
 178         *p++ = htonl((u32) time.tv_sec);
 179         *p++ = htonl(time.tv_nsec ? time.tv_nsec / 1000 : 0);
 180         *p++ = htonl((u32) stat->ctime.tv_sec);
 181         *p++ = htonl(stat->ctime.tv_nsec ? stat->ctime.tv_nsec / 1000 : 0);
 182
 183         return p;
 184 }
 185
 186 /* Helper function for NFSv2 ACL code */
 187 __be32 *nfs2svc_encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp, struct kstat *stat)
 188 {
 189         return encode_fattr(rqstp, p, fhp, stat);
 190 }
 191
 192 /*
 193  * XDR decode functions
 194  */
 195
 196 int
 197 nfssvc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p)
 198 {
 199         struct nfsd_fhandle *args = rqstp->rq_argp;
 200
 201         p = decode_fh(p, &args->fh);
 202         if (!p)
 203                 return 0;
 204         return xdr_argsize_check(rqstp, p);
 205 }
 206
 207 int
 208 nfssvc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p)
 209 {
 210         struct nfsd_sattrargs *args = rqstp->rq_argp;
 211
 212         p = decode_fh(p, &args->fh);
 213         if (!p)
 214                 return 0;
 215         p = decode_sattr(p, &args->attrs, nfsd_user_namespace(rqstp));
 216
 217         return xdr_argsize_check(rqstp, p);
 218 }
 219
 220 int
 221 nfssvc_decode_diropargs(struct svc_rqst *rqstp, __be32 *p)
 222 {
 223         struct nfsd_diropargs *args = rqstp->rq_argp;
 224
 225         if (!(p = decode_fh(p, &args->fh))
 226          || !(p = decode_filename(p, &args->name, &args->len)))
 227                 return 0;
 228
 229         return xdr_argsize_check(rqstp, p);
 230 }
 231
 232 int
 233 nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
 234 {
 235         struct nfsd_readargs *args = rqstp->rq_argp;
 236         unsigned int len;
 237         int v;
 238         p = decode_fh(p, &args->fh);
 239         if (!p)
 240                 return 0;
 241
 242         args->offset    = ntohl(*p++);
 243         len = args->count     = ntohl(*p++);
 244         p++; /* totalcount - unused */
 245
 246         len = min_t(unsigned int, len, NFSSVC_MAXBLKSIZE_V2);
 247
 248         /* set up somewhere to store response.
 249          * We take pages, put them on reslist and include in iovec
 250          */
 251         v=0;
 252         while (len > 0) {
 253                 struct page *p = *(rqstp->rq_next_page++);
 254
 255                 rqstp->rq_vec[v].iov_base = page_address(p);
 256                 rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
 257                 len -= rqstp->rq_vec[v].iov_len;
 258                 v++;
 259         }
 260         args->vlen = v;
 261         return xdr_argsize_check(rqstp, p);
 262 }
 263
 264 int
 265 nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
 266 {
 267         struct nfsd_writeargs *args = rqstp->rq_argp;
 268         unsigned int len, hdr, dlen;
 269         struct kvec *head = rqstp->rq_arg.head;
 270
 271         p = decode_fh(p, &args->fh);
 272         if (!p)
 273                 return 0;
 274
 275         p++;                            /* beginoffset */
 276         args->offset = ntohl(*p++);     /* offset */
 277         p++;                            /* totalcount */
 278         len = args->len = ntohl(*p++);
 279         /*
 280          * The protocol specifies a maximum of 8192 bytes.
 281          */
 282         if (len > NFSSVC_MAXBLKSIZE_V2)
 283                 return 0;
 284
 285         /*
 286          * Check to make sure that we got the right number of
 287          * bytes.
 288          */
 289         hdr = (void*)p - head->iov_base;
 290         if (hdr > head->iov_len)
 291                 return 0;
 292         dlen = head->iov_len + rqstp->rq_arg.page_len - hdr;
 293
 294         /*
 295          * Round the length of the data which was specified up to
 296          * the next multiple of XDR units and then compare that
 297          * against the length which was actually received.
 298          * Note that when RPCSEC/GSS (for example) is used, the
 299          * data buffer can be padded so dlen might be larger
 300          * than required.  It must never be smaller.
 301          */
 302         if (dlen < XDR_QUADLEN(len)*4)
 303                 return 0;
 304
 305         args->first.iov_base = (void *)p;
 306         args->first.iov_len = head->iov_len - hdr;
 307         return 1;
 308 }
 309
 310 int
 311 nfssvc_decode_createargs(struct svc_rqst *rqstp, __be32 *p)
 312 {
 313         struct nfsd_createargs *args = rqstp->rq_argp;
 314
 315         if (   !(p = decode_fh(p, &args->fh))
 316             || !(p = decode_filename(p, &args->name, &args->len)))
 317                 return 0;
 318         p = decode_sattr(p, &args->attrs, nfsd_user_namespace(rqstp));
 319
 320         return xdr_argsize_check(rqstp, p);
 321 }
 322
 323 int
 324 nfssvc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p)
 325 {
 326         struct nfsd_renameargs *args = rqstp->rq_argp;
 327
 328         if (!(p = decode_fh(p, &args->ffh))
 329          || !(p = decode_filename(p, &args->fname, &args->flen))
 330          || !(p = decode_fh(p, &args->tfh))
 331          || !(p = decode_filename(p, &args->tname, &args->tlen)))
 332                 return 0;
 333
 334         return xdr_argsize_check(rqstp, p);
 335 }
 336
 337 int
 338 nfssvc_decode_readlinkargs(struct svc_rqst *rqstp, __be32 *p)
 339 {
 340         struct nfsd_readlinkargs *args = rqstp->rq_argp;
 341
 342         p = decode_fh(p, &args->fh);
 343         if (!p)
 344                 return 0;
 345         args->buffer = page_address(*(rqstp->rq_next_page++));
 346
 347         return xdr_argsize_check(rqstp, p);
 348 }
 349
 350 int
 351 nfssvc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
 352 {
 353         struct nfsd_linkargs *args = rqstp->rq_argp;
 354
 355         if (!(p = decode_fh(p, &args->ffh))
 356          || !(p = decode_fh(p, &args->tfh))
 357          || !(p = decode_filename(p, &args->tname, &args->tlen)))
 358                 return 0;
 359
 360         return xdr_argsize_check(rqstp, p);
 361 }
 362
 363 int
 364 nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
 365 {
 366         struct nfsd_symlinkargs *args = rqstp->rq_argp;
 367         char *base = (char *)p;
 368         size_t xdrlen;
 369
 370         if (   !(p = decode_fh(p, &args->ffh))
 371             || !(p = decode_filename(p, &args->fname, &args->flen)))
 372                 return 0;
 373
 374         args->tlen = ntohl(*p++);
 375         if (args->tlen == 0)
 376                 return 0;
 377
 378         args->first.iov_base = p;
 379         args->first.iov_len = rqstp->rq_arg.head[0].iov_len;
 380         args->first.iov_len -= (char *)p - base;
 381
 382         /* This request is never larger than a page. Therefore,
 383          * transport will deliver either:
 384          * 1. pathname in the pagelist -> sattr is in the tail.
 385          * 2. everything in the head buffer -> sattr is in the head.
 386          */
 387         if (rqstp->rq_arg.page_len) {
 388                 if (args->tlen != rqstp->rq_arg.page_len)
 389                         return 0;
 390                 p = rqstp->rq_arg.tail[0].iov_base;
 391         } else {
 392                 xdrlen = XDR_QUADLEN(args->tlen);
 393                 if (xdrlen > args->first.iov_len - (8 * sizeof(__be32)))
 394                         return 0;
 395                 p += xdrlen;
 396         }
 397         decode_sattr(p, &args->attrs, nfsd_user_namespace(rqstp));
 398
 399         return 1;
 400 }
 401
 402 int
 403 nfssvc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
 404 {
 405         struct nfsd_readdirargs *args = rqstp->rq_argp;
 406
 407         p = decode_fh(p, &args->fh);
 408         if (!p)
 409                 return 0;
 410         args->cookie = ntohl(*p++);
 411         args->count  = ntohl(*p++);
 412         args->count  = min_t(u32, args->count, PAGE_SIZE);
 413         args->buffer = page_address(*(rqstp->rq_next_page++));
 414
 415         return xdr_argsize_check(rqstp, p);
 416 }
 417
 418 /*
 419  * XDR encode functions
 420  */
 421
 422 int
 423 nfssvc_encode_stat(struct svc_rqst *rqstp, __be32 *p)
 424 {
 425         struct nfsd_stat *resp = rqstp->rq_resp;
 426
 427         *p++ = resp->status;
 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++ = resp->status;
 437         if (resp->status != nfs_ok)
 438                 goto out;
 439         p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
 440 out:
 441         return xdr_ressize_check(rqstp, p);
 442 }
 443
 444 int
 445 nfssvc_encode_diropres(struct svc_rqst *rqstp, __be32 *p)
 446 {
 447         struct nfsd_diropres *resp = rqstp->rq_resp;
 448
 449         *p++ = resp->status;
 450         if (resp->status != nfs_ok)
 451                 goto out;
 452         p = encode_fh(p, &resp->fh);
 453         p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
 454 out:
 455         return xdr_ressize_check(rqstp, p);
 456 }
 457
 458 int
 459 nfssvc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
 460 {
 461         struct nfsd_readlinkres *resp = rqstp->rq_resp;
 462         struct kvec *head = rqstp->rq_res.head;
 463
 464         *p++ = resp->status;
 465         if (resp->status != nfs_ok)
 466                 return xdr_ressize_check(rqstp, p);
 467
 468         *p++ = htonl(resp->len);
 469         xdr_ressize_check(rqstp, p);
 470         rqstp->rq_res.page_len = resp->len;
 471         if (resp->len & 3) {
 472                 /* need to pad the tail */
 473                 rqstp->rq_res.tail[0].iov_base = p;
 474                 *p = 0;
 475                 rqstp->rq_res.tail[0].iov_len = 4 - (resp->len&3);
 476         }
 477         if (svc_encode_result_payload(rqstp, head->iov_len, resp->len))
 478                 return 0;
 479         return 1;
 480 }
 481
 482 int
 483 nfssvc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
 484 {
 485         struct nfsd_readres *resp = rqstp->rq_resp;
 486         struct kvec *head = rqstp->rq_res.head;
 487
 488         *p++ = resp->status;
 489         if (resp->status != nfs_ok)
 490                 return xdr_ressize_check(rqstp, p);
 491
 492         p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
 493         *p++ = htonl(resp->count);
 494         xdr_ressize_check(rqstp, p);
 495
 496         /* now update rqstp->rq_res to reflect data as well */
 497         rqstp->rq_res.page_len = resp->count;
 498         if (resp->count & 3) {
 499                 /* need to pad the tail */
 500                 rqstp->rq_res.tail[0].iov_base = p;
 501                 *p = 0;
 502                 rqstp->rq_res.tail[0].iov_len = 4 - (resp->count&3);
 503         }
 504         if (svc_encode_result_payload(rqstp, head->iov_len, resp->count))
 505                 return 0;
 506         return 1;
 507 }
 508
 509 int
 510 nfssvc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
 511 {
 512         struct nfsd_readdirres *resp = rqstp->rq_resp;
 513
 514         *p++ = resp->status;
 515         if (resp->status != nfs_ok)
 516                 return xdr_ressize_check(rqstp, p);
 517
 518         xdr_ressize_check(rqstp, p);
 519         p = resp->buffer;
 520         *p++ = 0;                       /* no more entries */
 521         *p++ = htonl((resp->common.err == nfserr_eof));
 522         rqstp->rq_res.page_len = (((unsigned long)p-1) & ~PAGE_MASK)+1;
 523
 524         return 1;
 525 }
 526
 527 int
 528 nfssvc_encode_statfsres(struct svc_rqst *rqstp, __be32 *p)
 529 {
 530         struct nfsd_statfsres *resp = rqstp->rq_resp;
 531         struct kstatfs  *stat = &resp->stats;
 532
 533         *p++ = resp->status;
 534         if (resp->status != nfs_ok)
 535                 return xdr_ressize_check(rqstp, p);
 536
 537         *p++ = htonl(NFSSVC_MAXBLKSIZE_V2);     /* max transfer size */
 538         *p++ = htonl(stat->f_bsize);
 539         *p++ = htonl(stat->f_blocks);
 540         *p++ = htonl(stat->f_bfree);
 541         *p++ = htonl(stat->f_bavail);
 542         return xdr_ressize_check(rqstp, p);
 543 }
 544
 545 int
 546 nfssvc_encode_entry(void *ccdv, const char *name,
 547                     int namlen, loff_t offset, u64 ino, unsigned int d_type)
 548 {
 549         struct readdir_cd *ccd = ccdv;
 550         struct nfsd_readdirres *cd = container_of(ccd, struct nfsd_readdirres, common);
 551         __be32  *p = cd->buffer;
 552         int     buflen, slen;
 553
 554         /*
 555         dprintk("nfsd: entry(%.*s off %ld ino %ld)\n",
 556                         namlen, name, offset, ino);
 557          */
 558
 559         if (offset > ~((u32) 0)) {
 560                 cd->common.err = nfserr_fbig;
 561                 return -EINVAL;
 562         }
 563         if (cd->offset)
 564                 *cd->offset = htonl(offset);
 565
 566         /* truncate filename */
 567         namlen = min(namlen, NFS2_MAXNAMLEN);
 568         slen = XDR_QUADLEN(namlen);
 569
 570         if ((buflen = cd->buflen - slen - 4) < 0) {
 571                 cd->common.err = nfserr_toosmall;
 572                 return -EINVAL;
 573         }
 574         if (ino > ~((u32) 0)) {
 575                 cd->common.err = nfserr_fbig;
 576                 return -EINVAL;
 577         }
 578         *p++ = xdr_one;                         /* mark entry present */
 579         *p++ = htonl((u32) ino);                /* file id */
 580         p    = xdr_encode_array(p, name, namlen);/* name length & name */
 581         cd->offset = p;                 /* remember pointer */
 582         *p++ = htonl(~0U);              /* offset of next entry */
 583
 584         cd->buflen = buflen;
 585         cd->buffer = p;
 586         cd->common.err = nfs_ok;
 587         return 0;
 588 }
 589
 590 /*
 591  * XDR release functions
 592  */
 593 void nfssvc_release_attrstat(struct svc_rqst *rqstp)
 594 {
 595         struct nfsd_attrstat *resp = rqstp->rq_resp;
 596
 597         fh_put(&resp->fh);
 598 }
 599
 600 void nfssvc_release_diropres(struct svc_rqst *rqstp)
 601 {
 602         struct nfsd_diropres *resp = rqstp->rq_resp;
 603
 604         fh_put(&resp->fh);
 605 }
 606
 607 void nfssvc_release_readres(struct svc_rqst *rqstp)
 608 {
 609         struct nfsd_readres *resp = rqstp->rq_resp;
 610
 611         fh_put(&resp->fh);
 612 }