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)
  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(&init_user_ns, 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(&init_user_ns, 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 dentry   *dentry = fhp->fh_dentry;
 133         int type;
 134         struct timespec time;
 135         u32 f;
 136
 137         type = (stat->mode & S_IFMT);
 138
 139         *p++ = htonl(nfs_ftypes[type >> 12]);
 140         *p++ = htonl((u32) stat->mode);
 141         *p++ = htonl((u32) stat->nlink);
 142         *p++ = htonl((u32) from_kuid(&init_user_ns, stat->uid));
 143         *p++ = htonl((u32) from_kgid(&init_user_ns, stat->gid));
 144
 145         if (S_ISLNK(type) && stat->size > NFS_MAXPATHLEN) {
 146                 *p++ = htonl(NFS_MAXPATHLEN);
 147         } else {
 148                 *p++ = htonl((u32) stat->size);
 149         }
 150         *p++ = htonl((u32) stat->blksize);
 151         if (S_ISCHR(type) || S_ISBLK(type))
 152                 *p++ = htonl(new_encode_dev(stat->rdev));
 153         else
 154                 *p++ = htonl(0xffffffff);
 155         *p++ = htonl((u32) stat->blocks);
 156         switch (fsid_source(fhp)) {
 157         default:
 158         case FSIDSOURCE_DEV:
 159                 *p++ = htonl(new_encode_dev(stat->dev));
 160                 break;
 161         case FSIDSOURCE_FSID:
 162                 *p++ = htonl((u32) fhp->fh_export->ex_fsid);
 163                 break;
 164         case FSIDSOURCE_UUID:
 165                 f = ((u32*)fhp->fh_export->ex_uuid)[0];
 166                 f ^= ((u32*)fhp->fh_export->ex_uuid)[1];
 167                 f ^= ((u32*)fhp->fh_export->ex_uuid)[2];
 168                 f ^= ((u32*)fhp->fh_export->ex_uuid)[3];
 169                 *p++ = htonl(f);
 170                 break;
 171         }
 172         *p++ = htonl((u32) stat->ino);
 173         *p++ = htonl((u32) stat->atime.tv_sec);
 174         *p++ = htonl(stat->atime.tv_nsec ? stat->atime.tv_nsec / 1000 : 0);
 175         time = stat->mtime;
 176         lease_get_mtime(d_inode(dentry), &time);
 177         *p++ = htonl((u32) time.tv_sec);
 178         *p++ = htonl(time.tv_nsec ? time.tv_nsec / 1000 : 0);
 179         *p++ = htonl((u32) stat->ctime.tv_sec);
 180         *p++ = htonl(stat->ctime.tv_nsec ? stat->ctime.tv_nsec / 1000 : 0);
 181
 182         return p;
 183 }
 184
 185 /* Helper function for NFSv2 ACL code */
 186 __be32 *nfs2svc_encode_fattr(struct svc_rqst *rqstp, __be32 *p, struct svc_fh *fhp, struct kstat *stat)
 187 {
 188         return encode_fattr(rqstp, p, fhp, stat);
 189 }
 190
 191 /*
 192  * XDR decode functions
 193  */
 194 int
 195 nfssvc_decode_void(struct svc_rqst *rqstp, __be32 *p)
 196 {
 197         return xdr_argsize_check(rqstp, p);
 198 }
 199
 200 int
 201 nfssvc_decode_fhandle(struct svc_rqst *rqstp, __be32 *p)
 202 {
 203         struct nfsd_fhandle *args = rqstp->rq_argp;
 204
 205         p = decode_fh(p, &args->fh);
 206         if (!p)
 207                 return 0;
 208         return xdr_argsize_check(rqstp, p);
 209 }
 210
 211 int
 212 nfssvc_decode_sattrargs(struct svc_rqst *rqstp, __be32 *p)
 213 {
 214         struct nfsd_sattrargs *args = rqstp->rq_argp;
 215
 216         p = decode_fh(p, &args->fh);
 217         if (!p)
 218                 return 0;
 219         p = decode_sattr(p, &args->attrs);
 220
 221         return xdr_argsize_check(rqstp, p);
 222 }
 223
 224 int
 225 nfssvc_decode_diropargs(struct svc_rqst *rqstp, __be32 *p)
 226 {
 227         struct nfsd_diropargs *args = rqstp->rq_argp;
 228
 229         if (!(p = decode_fh(p, &args->fh))
 230          || !(p = decode_filename(p, &args->name, &args->len)))
 231                 return 0;
 232
 233         return xdr_argsize_check(rqstp, p);
 234 }
 235
 236 int
 237 nfssvc_decode_readargs(struct svc_rqst *rqstp, __be32 *p)
 238 {
 239         struct nfsd_readargs *args = rqstp->rq_argp;
 240         unsigned int len;
 241         int v;
 242         p = decode_fh(p, &args->fh);
 243         if (!p)
 244                 return 0;
 245
 246         args->offset    = ntohl(*p++);
 247         len = args->count     = ntohl(*p++);
 248         p++; /* totalcount - unused */
 249
 250         len = min_t(unsigned int, len, NFSSVC_MAXBLKSIZE_V2);
 251
 252         /* set up somewhere to store response.
 253          * We take pages, put them on reslist and include in iovec
 254          */
 255         v=0;
 256         while (len > 0) {
 257                 struct page *p = *(rqstp->rq_next_page++);
 258
 259                 rqstp->rq_vec[v].iov_base = page_address(p);
 260                 rqstp->rq_vec[v].iov_len = min_t(unsigned int, len, PAGE_SIZE);
 261                 len -= rqstp->rq_vec[v].iov_len;
 262                 v++;
 263         }
 264         args->vlen = v;
 265         return xdr_argsize_check(rqstp, p);
 266 }
 267
 268 int
 269 nfssvc_decode_writeargs(struct svc_rqst *rqstp, __be32 *p)
 270 {
 271         struct nfsd_writeargs *args = rqstp->rq_argp;
 272         unsigned int len, hdr, dlen;
 273         struct kvec *head = rqstp->rq_arg.head;
 274
 275         p = decode_fh(p, &args->fh);
 276         if (!p)
 277                 return 0;
 278
 279         p++;                            /* beginoffset */
 280         args->offset = ntohl(*p++);     /* offset */
 281         p++;                            /* totalcount */
 282         len = args->len = ntohl(*p++);
 283         /*
 284          * The protocol specifies a maximum of 8192 bytes.
 285          */
 286         if (len > NFSSVC_MAXBLKSIZE_V2)
 287                 return 0;
 288
 289         /*
 290          * Check to make sure that we got the right number of
 291          * bytes.
 292          */
 293         hdr = (void*)p - head->iov_base;
 294         if (hdr > head->iov_len)
 295                 return 0;
 296         dlen = head->iov_len + rqstp->rq_arg.page_len - hdr;
 297
 298         /*
 299          * Round the length of the data which was specified up to
 300          * the next multiple of XDR units and then compare that
 301          * against the length which was actually received.
 302          * Note that when RPCSEC/GSS (for example) is used, the
 303          * data buffer can be padded so dlen might be larger
 304          * than required.  It must never be smaller.
 305          */
 306         if (dlen < XDR_QUADLEN(len)*4)
 307                 return 0;
 308
 309         args->first.iov_base = (void *)p;
 310         args->first.iov_len = head->iov_len - hdr;
 311         return 1;
 312 }
 313
 314 int
 315 nfssvc_decode_createargs(struct svc_rqst *rqstp, __be32 *p)
 316 {
 317         struct nfsd_createargs *args = rqstp->rq_argp;
 318
 319         if (   !(p = decode_fh(p, &args->fh))
 320             || !(p = decode_filename(p, &args->name, &args->len)))
 321                 return 0;
 322         p = decode_sattr(p, &args->attrs);
 323
 324         return xdr_argsize_check(rqstp, p);
 325 }
 326
 327 int
 328 nfssvc_decode_renameargs(struct svc_rqst *rqstp, __be32 *p)
 329 {
 330         struct nfsd_renameargs *args = rqstp->rq_argp;
 331
 332         if (!(p = decode_fh(p, &args->ffh))
 333          || !(p = decode_filename(p, &args->fname, &args->flen))
 334          || !(p = decode_fh(p, &args->tfh))
 335          || !(p = decode_filename(p, &args->tname, &args->tlen)))
 336                 return 0;
 337
 338         return xdr_argsize_check(rqstp, p);
 339 }
 340
 341 int
 342 nfssvc_decode_readlinkargs(struct svc_rqst *rqstp, __be32 *p)
 343 {
 344         struct nfsd_readlinkargs *args = rqstp->rq_argp;
 345
 346         p = decode_fh(p, &args->fh);
 347         if (!p)
 348                 return 0;
 349         args->buffer = page_address(*(rqstp->rq_next_page++));
 350
 351         return xdr_argsize_check(rqstp, p);
 352 }
 353
 354 int
 355 nfssvc_decode_linkargs(struct svc_rqst *rqstp, __be32 *p)
 356 {
 357         struct nfsd_linkargs *args = rqstp->rq_argp;
 358
 359         if (!(p = decode_fh(p, &args->ffh))
 360          || !(p = decode_fh(p, &args->tfh))
 361          || !(p = decode_filename(p, &args->tname, &args->tlen)))
 362                 return 0;
 363
 364         return xdr_argsize_check(rqstp, p);
 365 }
 366
 367 int
 368 nfssvc_decode_symlinkargs(struct svc_rqst *rqstp, __be32 *p)
 369 {
 370         struct nfsd_symlinkargs *args = rqstp->rq_argp;
 371         char *base = (char *)p;
 372         size_t xdrlen;
 373
 374         if (   !(p = decode_fh(p, &args->ffh))
 375             || !(p = decode_filename(p, &args->fname, &args->flen)))
 376                 return 0;
 377
 378         args->tlen = ntohl(*p++);
 379         if (args->tlen == 0)
 380                 return 0;
 381
 382         args->first.iov_base = p;
 383         args->first.iov_len = rqstp->rq_arg.head[0].iov_len;
 384         args->first.iov_len -= (char *)p - base;
 385
 386         /* This request is never larger than a page. Therefore,
 387          * transport will deliver either:
 388          * 1. pathname in the pagelist -> sattr is in the tail.
 389          * 2. everything in the head buffer -> sattr is in the head.
 390          */
 391         if (rqstp->rq_arg.page_len) {
 392                 if (args->tlen != rqstp->rq_arg.page_len)
 393                         return 0;
 394                 p = rqstp->rq_arg.tail[0].iov_base;
 395         } else {
 396                 xdrlen = XDR_QUADLEN(args->tlen);
 397                 if (xdrlen > args->first.iov_len - (8 * sizeof(__be32)))
 398                         return 0;
 399                 p += xdrlen;
 400         }
 401         decode_sattr(p, &args->attrs);
 402
 403         return 1;
 404 }
 405
 406 int
 407 nfssvc_decode_readdirargs(struct svc_rqst *rqstp, __be32 *p)
 408 {
 409         struct nfsd_readdirargs *args = rqstp->rq_argp;
 410
 411         p = decode_fh(p, &args->fh);
 412         if (!p)
 413                 return 0;
 414         args->cookie = ntohl(*p++);
 415         args->count  = ntohl(*p++);
 416         args->count  = min_t(u32, args->count, PAGE_SIZE);
 417         args->buffer = page_address(*(rqstp->rq_next_page++));
 418
 419         return xdr_argsize_check(rqstp, p);
 420 }
 421
 422 /*
 423  * XDR encode functions
 424  */
 425 int
 426 nfssvc_encode_void(struct svc_rqst *rqstp, __be32 *p)
 427 {
 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 = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
 437         return xdr_ressize_check(rqstp, p);
 438 }
 439
 440 int
 441 nfssvc_encode_diropres(struct svc_rqst *rqstp, __be32 *p)
 442 {
 443         struct nfsd_diropres *resp = rqstp->rq_resp;
 444
 445         p = encode_fh(p, &resp->fh);
 446         p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
 447         return xdr_ressize_check(rqstp, p);
 448 }
 449
 450 int
 451 nfssvc_encode_readlinkres(struct svc_rqst *rqstp, __be32 *p)
 452 {
 453         struct nfsd_readlinkres *resp = rqstp->rq_resp;
 454
 455         *p++ = htonl(resp->len);
 456         xdr_ressize_check(rqstp, p);
 457         rqstp->rq_res.page_len = resp->len;
 458         if (resp->len & 3) {
 459                 /* need to pad the tail */
 460                 rqstp->rq_res.tail[0].iov_base = p;
 461                 *p = 0;
 462                 rqstp->rq_res.tail[0].iov_len = 4 - (resp->len&3);
 463         }
 464         return 1;
 465 }
 466
 467 int
 468 nfssvc_encode_readres(struct svc_rqst *rqstp, __be32 *p)
 469 {
 470         struct nfsd_readres *resp = rqstp->rq_resp;
 471
 472         p = encode_fattr(rqstp, p, &resp->fh, &resp->stat);
 473         *p++ = htonl(resp->count);
 474         xdr_ressize_check(rqstp, p);
 475
 476         /* now update rqstp->rq_res to reflect data as well */
 477         rqstp->rq_res.page_len = resp->count;
 478         if (resp->count & 3) {
 479                 /* need to pad the tail */
 480                 rqstp->rq_res.tail[0].iov_base = p;
 481                 *p = 0;
 482                 rqstp->rq_res.tail[0].iov_len = 4 - (resp->count&3);
 483         }
 484         return 1;
 485 }
 486
 487 int
 488 nfssvc_encode_readdirres(struct svc_rqst *rqstp, __be32 *p)
 489 {
 490         struct nfsd_readdirres *resp = rqstp->rq_resp;
 491
 492         xdr_ressize_check(rqstp, p);
 493         p = resp->buffer;
 494         *p++ = 0;                       /* no more entries */
 495         *p++ = htonl((resp->common.err == nfserr_eof));
 496         rqstp->rq_res.page_len = (((unsigned long)p-1) & ~PAGE_MASK)+1;
 497
 498         return 1;
 499 }
 500
 501 int
 502 nfssvc_encode_statfsres(struct svc_rqst *rqstp, __be32 *p)
 503 {
 504         struct nfsd_statfsres *resp = rqstp->rq_resp;
 505         struct kstatfs  *stat = &resp->stats;
 506
 507         *p++ = htonl(NFSSVC_MAXBLKSIZE_V2);     /* max transfer size */
 508         *p++ = htonl(stat->f_bsize);
 509         *p++ = htonl(stat->f_blocks);
 510         *p++ = htonl(stat->f_bfree);
 511         *p++ = htonl(stat->f_bavail);
 512         return xdr_ressize_check(rqstp, p);
 513 }
 514
 515 int
 516 nfssvc_encode_entry(void *ccdv, const char *name,
 517                     int namlen, loff_t offset, u64 ino, unsigned int d_type)
 518 {
 519         struct readdir_cd *ccd = ccdv;
 520         struct nfsd_readdirres *cd = container_of(ccd, struct nfsd_readdirres, common);
 521         __be32  *p = cd->buffer;
 522         int     buflen, slen;
 523
 524         /*
 525         dprintk("nfsd: entry(%.*s off %ld ino %ld)\n",
 526                         namlen, name, offset, ino);
 527          */
 528
 529         if (offset > ~((u32) 0)) {
 530                 cd->common.err = nfserr_fbig;
 531                 return -EINVAL;
 532         }
 533         if (cd->offset)
 534                 *cd->offset = htonl(offset);
 535
 536         /* truncate filename */
 537         namlen = min(namlen, NFS2_MAXNAMLEN);
 538         slen = XDR_QUADLEN(namlen);
 539
 540         if ((buflen = cd->buflen - slen - 4) < 0) {
 541                 cd->common.err = nfserr_toosmall;
 542                 return -EINVAL;
 543         }
 544         if (ino > ~((u32) 0)) {
 545                 cd->common.err = nfserr_fbig;
 546                 return -EINVAL;
 547         }
 548         *p++ = xdr_one;                         /* mark entry present */
 549         *p++ = htonl((u32) ino);                /* file id */
 550         p    = xdr_encode_array(p, name, namlen);/* name length & name */
 551         cd->offset = p;                 /* remember pointer */
 552         *p++ = htonl(~0U);              /* offset of next entry */
 553
 554         cd->buflen = buflen;
 555         cd->buffer = p;
 556         cd->common.err = nfs_ok;
 557         return 0;
 558 }
 559
 560 /*
 561  * XDR release functions
 562  */
 563 void
 564 nfssvc_release_fhandle(struct svc_rqst *rqstp)
 565 {
 566         struct nfsd_fhandle *resp = rqstp->rq_resp;
 567
 568         fh_put(&resp->fh);
 569 }