Dogcows Code - chaz/tar/blob - src/xattrs.c

   1 /* Support for extended attributes.
   2
   3    Copyright (C) 2006-2014 Free Software Foundation, Inc.
   4
   5    This file is part of GNU tar.
   6
   7    GNU tar is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    GNU tar is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.
  19
  20    Written by James Antill, on 2006-07-27.  */
  21
  22 #include <config.h>
  23 #include <system.h>
  24
  25 #include <fnmatch.h>
  26 #include <quotearg.h>
  27
  28 #include "common.h"
  29
  30 #include "xattr-at.h"
  31 #include "selinux-at.h"
  32
  33 struct xattrs_mask_map
  34 {
  35   const char **masks;
  36   size_t size;
  37   size_t used;
  38 };
  39
  40 /* list of fnmatch patterns */
  41 static struct
  42 {
  43   /* lists of fnmatch patterns */
  44   struct xattrs_mask_map incl;
  45   struct xattrs_mask_map excl;
  46 } xattrs_setup;
  47
  48 /* disable posix acls when problem found in gnulib script m4/acl.m4 */
  49 #if ! USE_ACL
  50 # undef HAVE_POSIX_ACLS
  51 #endif
  52
  53 #ifdef HAVE_POSIX_ACLS
  54 # include "acl.h"
  55 # include <sys/acl.h>
  56 #endif
  57
  58 #ifdef HAVE_POSIX_ACLS
  59
  60 /* acl-at wrappers, TODO: move to gnulib in future? */
  61 static acl_t acl_get_file_at (int, const char *, acl_type_t);
  62 static int acl_set_file_at (int, const char *, acl_type_t, acl_t);
  63 static int file_has_acl_at (int, char const *, struct stat const *);
  64
  65 /* acl_get_file_at */
  66 #define AT_FUNC_NAME acl_get_file_at
  67 #define AT_FUNC_RESULT acl_t
  68 #define AT_FUNC_FAIL (acl_t)NULL
  69 #define AT_FUNC_F1 acl_get_file
  70 #define AT_FUNC_POST_FILE_PARAM_DECLS   , acl_type_t type
  71 #define AT_FUNC_POST_FILE_ARGS          , type
  72 #include "at-func.c"
  73 #undef AT_FUNC_NAME
  74 #undef AT_FUNC_F1
  75 #undef AT_FUNC_RESULT
  76 #undef AT_FUNC_FAIL
  77 #undef AT_FUNC_POST_FILE_PARAM_DECLS
  78 #undef AT_FUNC_POST_FILE_ARGS
  79
  80 /* acl_set_file_at */
  81 #define AT_FUNC_NAME acl_set_file_at
  82 #define AT_FUNC_F1 acl_set_file
  83 #define AT_FUNC_POST_FILE_PARAM_DECLS   , acl_type_t type, acl_t acl
  84 #define AT_FUNC_POST_FILE_ARGS          , type, acl
  85 #include "at-func.c"
  86 #undef AT_FUNC_NAME
  87 #undef AT_FUNC_F1
  88 #undef AT_FUNC_POST_FILE_PARAM_DECLS
  89 #undef AT_FUNC_POST_FILE_ARGS
  90
  91 /* gnulib file_has_acl_at */
  92 #define AT_FUNC_NAME file_has_acl_at
  93 #define AT_FUNC_F1 file_has_acl
  94 #define AT_FUNC_POST_FILE_PARAM_DECLS   , struct stat const *st
  95 #define AT_FUNC_POST_FILE_ARGS          , st
  96 #include "at-func.c"
  97 #undef AT_FUNC_NAME
  98 #undef AT_FUNC_F1
  99 #undef AT_FUNC_POST_FILE_PARAM_DECLS
 100 #undef AT_FUNC_POST_FILE_ARGS
 101
 102 /* convert unix permissions into an ACL ... needed due to "default" ACLs */
 103 static acl_t
 104 perms2acl (int perms)
 105 {
 106   char val[] = "user::---,group::---,other::---";
 107   /*            0123456789 123456789 123456789 123456789 */
 108
 109   /* user */
 110   if (perms & 0400)
 111     val[6] = 'r';
 112   if (perms & 0200)
 113     val[7] = 'w';
 114   if (perms & 0100)
 115     val[8] = 'x';
 116
 117   /* group */
 118   if (perms & 0040)
 119     val[17] = 'r';
 120   if (perms & 0020)
 121     val[18] = 'w';
 122   if (perms & 0010)
 123     val[19] = 'x';
 124
 125   /* other */
 126   if (perms & 0004)
 127     val[28] = 'r';
 128   if (perms & 0002)
 129     val[29] = 'w';
 130   if (perms & 0001)
 131     val[30] = 'x';
 132
 133   return acl_from_text (val);
 134 }
 135
 136 static char *
 137 skip_to_ext_fields (char *ptr)
 138 {
 139   /* skip tag name (user/group/default/mask) */
 140   ptr += strcspn (ptr, ":,\n");
 141
 142   if (*ptr != ':')
 143     return ptr;
 144   ++ptr;
 145
 146   ptr += strcspn (ptr, ":,\n"); /* skip user/group name */
 147
 148   if (*ptr != ':')
 149     return ptr;
 150   ++ptr;
 151
 152   ptr += strcspn (ptr, ":,\n"); /* skip perms */
 153
 154   return ptr;
 155 }
 156
 157 /* The POSIX draft allows extra fields after the three main ones. Star
 158    uses this to add a fourth field for user/group which is the numeric ID.
 159    This function removes such extra fields by overwriting them with the
 160    characters that follow. */
 161 static char *
 162 fixup_extra_acl_fields (char *ptr)
 163 {
 164   char *src = ptr;
 165   char *dst = ptr;
 166
 167   while (*src)
 168     {
 169       const char *old = src;
 170       size_t len = 0;
 171
 172       src = skip_to_ext_fields (src);
 173       len = src - old;
 174       if (old != dst)
 175         memmove (dst, old, len);
 176       dst += len;
 177
 178       if (*src == ':')          /* We have extra fields, skip them all */
 179         src += strcspn (src, "\n,");
 180
 181       if ((*src == '\n') || (*src == ','))
 182         *dst++ = *src++;        /* also done when dst == src, but that's ok */
 183     }
 184   if (src != dst)
 185     *dst = 0;
 186
 187   return ptr;
 188 }
 189
 190 /* "system.posix_acl_access" */
 191 static void
 192 xattrs__acls_set (struct tar_stat_info const *st,
 193                   char const *file_name, int type,
 194                   char *ptr, size_t len, bool def)
 195 {
 196   acl_t acl;
 197
 198   if (ptr)
 199     {
 200       /* assert (strlen (ptr) == len); */
 201       ptr = fixup_extra_acl_fields (ptr);
 202
 203       acl = acl_from_text (ptr);
 204       acls_option = 1;
 205     }
 206   else if (acls_option > 0)
 207     acl = perms2acl (st->stat.st_mode);
 208   else
 209     return;  /* don't call acl functions unless we first hit an ACL, or
 210                 --acls was passed explicitly */
 211
 212   if (!acl)
 213     {
 214       call_arg_warn ("acl_from_text", file_name);
 215       return;
 216     }
 217
 218   if (acl_set_file_at (chdir_fd, file_name, type, acl) == -1)
 219     /* warn even if filesystem does not support acls */
 220     WARNOPT (WARN_XATTR_WRITE,
 221              (0, errno,
 222               _ ("acl_set_file_at: Cannot set POSIX ACLs for file '%s'"),
 223               file_name));
 224
 225   acl_free (acl);
 226 }
 227
 228 static void
 229 xattrs__acls_get_a (int parentfd, const char *file_name,
 230                     struct tar_stat_info *st,
 231                     char **ret_ptr, size_t * ret_len)
 232 {
 233   char *val = NULL;
 234   ssize_t len;
 235   acl_t acl;
 236
 237   if (!(acl = acl_get_file_at (parentfd, file_name, ACL_TYPE_ACCESS)))
 238     {
 239       if (errno != ENOTSUP)
 240         call_arg_warn ("acl_get_file_at", file_name);
 241       return;
 242     }
 243
 244   val = acl_to_text (acl, &len);
 245   acl_free (acl);
 246
 247   if (!val)
 248     {
 249       call_arg_warn ("acl_to_text", file_name);
 250       return;
 251     }
 252
 253   *ret_ptr = xstrdup (val);
 254   *ret_len = len;
 255
 256   acl_free (val);
 257 }
 258
 259 /* "system.posix_acl_default" */
 260 static void
 261 xattrs__acls_get_d (int parentfd, char const *file_name,
 262                     struct tar_stat_info *st,
 263                     char **ret_ptr, size_t * ret_len)
 264 {
 265   char *val = NULL;
 266   ssize_t len;
 267   acl_t acl;
 268
 269   if (!(acl = acl_get_file_at (parentfd, file_name, ACL_TYPE_DEFAULT)))
 270     {
 271       if (errno != ENOTSUP)
 272         call_arg_warn ("acl_get_file_at", file_name);
 273       return;
 274     }
 275
 276   val = acl_to_text (acl, &len);
 277   acl_free (acl);
 278
 279   if (!val)
 280     {
 281       call_arg_warn ("acl_to_text", file_name);
 282       return;
 283     }
 284
 285   *ret_ptr = xstrdup (val);
 286   *ret_len = len;
 287
 288   acl_free (val);
 289 }
 290 #endif /* HAVE_POSIX_ACLS */
 291
 292 static void
 293 acls_one_line (const char *prefix, char delim,
 294                const char *aclstring, size_t len)
 295 {
 296   /* support both long and short text representation of posix acls */
 297   struct obstack stk;
 298   int pref_len = strlen (prefix);
 299   const char *oldstring = aclstring;
 300   int pos = 0;
 301
 302   if (!aclstring || !len)
 303     return;
 304
 305   obstack_init (&stk);
 306   while (pos <= len)
 307     {
 308       int move = strcspn (aclstring, ",\n");
 309       if (!move)
 310         break;
 311
 312       if (oldstring != aclstring)
 313         obstack_1grow (&stk, delim);
 314
 315       obstack_grow (&stk, prefix, pref_len);
 316       obstack_grow (&stk, aclstring, move);
 317
 318       aclstring += move + 1;
 319     }
 320
 321   obstack_1grow (&stk, '\0');
 322
 323   fprintf (stdlis, "%s", (char *) obstack_finish (&stk));
 324
 325   obstack_free (&stk, NULL);
 326 }
 327
 328 void
 329 xattrs_acls_get (int parentfd, char const *file_name,
 330                  struct tar_stat_info *st, int fd, int xisfile)
 331 {
 332   if (acls_option > 0)
 333     {
 334 #ifndef HAVE_POSIX_ACLS
 335       static int done = 0;
 336       if (!done)
 337         WARN ((0, 0, _("POSIX ACL support is not available")));
 338       done = 1;
 339 #else
 340       int err = file_has_acl_at (parentfd, file_name, &st->stat);
 341       if (err == 0)
 342         return;
 343       if (err == -1)
 344         {
 345           call_arg_warn ("file_has_acl_at", file_name);
 346           return;
 347         }
 348
 349       xattrs__acls_get_a (parentfd, file_name, st,
 350                           &st->acls_a_ptr, &st->acls_a_len);
 351       if (!xisfile)
 352         xattrs__acls_get_d (parentfd, file_name, st,
 353                             &st->acls_d_ptr, &st->acls_d_len);
 354 #endif
 355     }
 356 }
 357
 358 void
 359 xattrs_acls_set (struct tar_stat_info const *st,
 360                  char const *file_name, char typeflag)
 361 {
 362   if (acls_option > 0 && typeflag != SYMTYPE)
 363     {
 364 #ifndef HAVE_POSIX_ACLS
 365       static int done = 0;
 366       if (!done)
 367         WARN ((0, 0, _("POSIX ACL support is not available")));
 368       done = 1;
 369 #else
 370       xattrs__acls_set (st, file_name, ACL_TYPE_ACCESS,
 371                         st->acls_a_ptr, st->acls_a_len, false);
 372       if (typeflag == DIRTYPE || typeflag == GNUTYPE_DUMPDIR)
 373         xattrs__acls_set (st, file_name, ACL_TYPE_DEFAULT,
 374                           st->acls_d_ptr, st->acls_d_len, true);
 375 #endif
 376     }
 377 }
 378
 379 static void
 380 mask_map_realloc (struct xattrs_mask_map *map)
 381 {
 382   if (map->used == map->size)
 383     {
 384       if (map->size == 0)
 385         map->size = 4;
 386       map->masks = x2nrealloc (map->masks, &map->size, sizeof (map->masks[0]));
 387     }
 388 }
 389
 390 void
 391 xattrs_mask_add (const char *mask, bool incl)
 392 {
 393   struct xattrs_mask_map *mask_map =
 394     incl ? &xattrs_setup.incl : &xattrs_setup.excl;
 395   /* ensure there is enough space */
 396   mask_map_realloc (mask_map);
 397   /* just assign pointers -- we silently expect that pointer "mask" is valid
 398      through the whole program (pointer to argv array) */
 399   mask_map->masks[mask_map->used++] = mask;
 400 }
 401
 402 static void
 403 clear_mask_map (struct xattrs_mask_map *mask_map)
 404 {
 405   if (mask_map->size)
 406     free (mask_map->masks);
 407 }
 408
 409 void
 410 xattrs_clear_setup (void)
 411 {
 412   clear_mask_map (&xattrs_setup.incl);
 413   clear_mask_map (&xattrs_setup.excl);
 414 }
 415
 416 /* get all xattrs from file given by FILE_NAME or FD (when non-zero).  This
 417    includes all the user.*, security.*, system.*, etc. available domains */
 418 void
 419 xattrs_xattrs_get (int parentfd, char const *file_name,
 420                    struct tar_stat_info *st, int fd)
 421 {
 422   if (xattrs_option > 0)
 423     {
 424 #ifndef HAVE_XATTRS
 425       static int done = 0;
 426       if (!done)
 427         WARN ((0, 0, _("XATTR support is not available")));
 428       done = 1;
 429 #else
 430       static size_t xsz = 1024;
 431       static char *xatrs = NULL;
 432       ssize_t xret = -1;
 433
 434       if (!xatrs)
 435         xatrs = x2nrealloc (xatrs, &xsz, 1);
 436
 437       while (((fd == 0) ?
 438               ((xret =
 439                 llistxattrat (parentfd, file_name, xatrs, xsz)) == -1) :
 440               ((xret = flistxattr (fd, xatrs, xsz)) == -1))
 441              && (errno == ERANGE))
 442         {
 443           xatrs = x2nrealloc (xatrs, &xsz, 1);
 444         }
 445
 446       if (xret == -1)
 447         call_arg_warn ((fd == 0) ? "llistxattrat" : "flistxattr", file_name);
 448       else
 449         {
 450           const char *attr = xatrs;
 451           static size_t asz = 1024;
 452           static char *val = NULL;
 453
 454           if (!val)
 455             val = x2nrealloc (val, &asz, 1);
 456
 457           while (xret > 0)
 458             {
 459               size_t len = strlen (attr);
 460               ssize_t aret = 0;
 461
 462               /* Archive all xattrs during creation, decide at extraction time
 463                * which ones are of interest/use for the target filesystem. */
 464               while (((fd == 0)
 465                       ? ((aret = lgetxattrat (parentfd, file_name, attr,
 466                                               val, asz)) == -1)
 467                       : ((aret = fgetxattr (fd, attr, val, asz)) == -1))
 468                      && (errno == ERANGE))
 469                 {
 470                   val = x2nrealloc (val, &asz, 1);
 471                 }
 472
 473               if (aret != -1)
 474                 xheader_xattr_add (st, attr, val, aret);
 475               else if (errno != ENOATTR)
 476                 call_arg_warn ((fd == 0) ? "lgetxattrat"
 477                                : "fgetxattr", file_name);
 478
 479               attr += len + 1;
 480               xret -= len + 1;
 481             }
 482         }
 483 #endif
 484     }
 485 }
 486
 487 #ifdef HAVE_XATTRS
 488 static void
 489 xattrs__fd_set (struct tar_stat_info const *st,
 490                 char const *file_name, char typeflag,
 491                 const char *attr, const char *ptr, size_t len)
 492 {
 493   if (ptr)
 494     {
 495       const char *sysname = "setxattrat";
 496       int ret = -1;
 497
 498       if (typeflag != SYMTYPE)
 499         ret = setxattrat (chdir_fd, file_name, attr, ptr, len, 0);
 500       else
 501         {
 502           sysname = "lsetxattr";
 503           ret = lsetxattrat (chdir_fd, file_name, attr, ptr, len, 0);
 504         }
 505
 506       if (ret == -1)
 507         WARNOPT (WARN_XATTR_WRITE,
 508                  (0, errno,
 509                   _("%s: Cannot set '%s' extended attribute for file '%s'"),
 510                   sysname, attr, file_name));
 511     }
 512 }
 513 #endif
 514
 515 /* lgetfileconat is called against FILE_NAME iff the FD parameter is set to
 516    zero, otherwise the fgetfileconat is used against correct file descriptor */
 517 void
 518 xattrs_selinux_get (int parentfd, char const *file_name,
 519                     struct tar_stat_info *st, int fd)
 520 {
 521   if (selinux_context_option > 0)
 522     {
 523 #if HAVE_SELINUX_SELINUX_H != 1
 524       static int done = 0;
 525       if (!done)
 526         WARN ((0, 0, _("SELinux support is not available")));
 527       done = 1;
 528 #else
 529       int result = fd ?
 530                     fgetfilecon (fd, &st->cntx_name)
 531                     : lgetfileconat (parentfd, file_name, &st->cntx_name);
 532
 533       if (result == -1 && errno != ENODATA && errno != ENOTSUP)
 534         call_arg_warn (fd ? "fgetfilecon" : "lgetfileconat", file_name);
 535 #endif
 536     }
 537 }
 538
 539 void
 540 xattrs_selinux_set (struct tar_stat_info const *st,
 541                     char const *file_name, char typeflag)
 542 {
 543   if (selinux_context_option > 0)
 544     {
 545 #if HAVE_SELINUX_SELINUX_H != 1
 546       static int done = 0;
 547       if (!done)
 548         WARN ((0, 0, _("SELinux support is not available")));
 549       done = 1;
 550 #else
 551       const char *sysname = "setfilecon";
 552       int ret;
 553
 554       if (!st->cntx_name)
 555         return;
 556
 557       if (typeflag != SYMTYPE)
 558         {
 559           ret = setfileconat (chdir_fd, file_name, st->cntx_name);
 560           sysname = "setfileconat";
 561         }
 562       else
 563         {
 564           ret = lsetfileconat (chdir_fd, file_name, st->cntx_name);
 565           sysname = "lsetfileconat";
 566         }
 567
 568       if (ret == -1)
 569         WARNOPT (WARN_XATTR_WRITE,
 570                  (0, errno,
 571                   _("%s: Cannot set SELinux context for file '%s'"),
 572                   sysname, file_name));
 573 #endif
 574     }
 575 }
 576
 577 static bool
 578 xattrs_matches_mask (const char *kw, struct xattrs_mask_map *mm)
 579 {
 580   int i;
 581
 582   if (!mm->size)
 583     return false;
 584
 585   for (i = 0; i < mm->used; i++)
 586     if (fnmatch (mm->masks[i], kw, 0) == 0)
 587       return true;
 588
 589   return false;
 590 }
 591
 592 #define USER_DOT_PFX "user."
 593
 594 static bool
 595 xattrs_kw_included (const char *kw, bool archiving)
 596 {
 597   if (xattrs_setup.incl.size)
 598     return xattrs_matches_mask (kw, &xattrs_setup.incl);
 599   else if (archiving)
 600     return true;
 601   else
 602     return strncmp (kw, USER_DOT_PFX, sizeof (USER_DOT_PFX) - 1) == 0;
 603 }
 604
 605 static bool
 606 xattrs_kw_excluded (const char *kw, bool archiving)
 607 {
 608   return xattrs_setup.excl.size ?
 609     xattrs_matches_mask (kw, &xattrs_setup.excl) : false;
 610 }
 611
 612 /* Check whether the xattr with keyword KW should be discarded from list of
 613    attributes that are going to be archived/excluded (set ARCHIVING=true for
 614    archiving, false for excluding) */
 615 static bool
 616 xattrs_masked_out (const char *kw, bool archiving)
 617 {
 618   return xattrs_kw_included (kw, archiving) ?
 619     xattrs_kw_excluded (kw, archiving) : true;
 620 }
 621
 622 void
 623 xattrs_xattrs_set (struct tar_stat_info const *st,
 624                    char const *file_name, char typeflag, int later_run)
 625 {
 626   if (xattrs_option > 0)
 627     {
 628 #ifndef HAVE_XATTRS
 629       static int done = 0;
 630       if (!done)
 631         WARN ((0, 0, _("XATTR support is not available")));
 632       done = 1;
 633 #else
 634       size_t scan = 0;
 635
 636       if (!st->xattr_map_size)
 637         return;
 638
 639       for (; scan < st->xattr_map_size; ++scan)
 640         {
 641           char *keyword = st->xattr_map[scan].xkey;
 642           keyword += strlen ("SCHILY.xattr.");
 643
 644           /* TODO: this 'later_run' workaround is temporary solution -> once
 645              capabilities should become fully supported by it's API and there
 646              should exist something like xattrs_capabilities_set() call.
 647              For a regular files: all extended attributes are restored during
 648              the first run except 'security.capability' which is restored in
 649              'later_run == 1'.  */
 650           if (typeflag == REGTYPE
 651               && later_run == !!strcmp (keyword, "security.capability"))
 652             continue;
 653
 654           if (xattrs_masked_out (keyword, false /* extracting */ ))
 655             /* we don't want to restore this keyword */
 656             continue;
 657
 658           xattrs__fd_set (st, file_name, typeflag, keyword,
 659                           st->xattr_map[scan].xval_ptr,
 660                           st->xattr_map[scan].xval_len);
 661         }
 662 #endif
 663     }
 664 }
 665
 666 void
 667 xattrs_print_char (struct tar_stat_info const *st, char *output)
 668 {
 669   int i;
 670
 671   if (verbose_option < 2)
 672     {
 673       *output = 0;
 674       return;
 675     }
 676
 677   if (xattrs_option > 0 || selinux_context_option > 0 || acls_option > 0)
 678     {
 679       /* placeholders */
 680       *output = ' ';
 681       output[1] = 0;
 682     }
 683
 684   if (xattrs_option > 0 && st->xattr_map_size)
 685     for (i = 0; i < st->xattr_map_size; ++i)
 686       {
 687         char *keyword = st->xattr_map[i].xkey + strlen ("SCHILY.xattr.");
 688         if (!xattrs_masked_out (keyword, false /* like extracting */ ))
 689           {
 690             *output = '*';
 691             break;
 692           }
 693       }
 694
 695   if (selinux_context_option > 0 && st->cntx_name)
 696     *output = '.';
 697
 698   if (acls_option && (st->acls_a_len || st->acls_d_len))
 699     *output = '+';
 700 }
 701
 702 void
 703 xattrs_print (struct tar_stat_info const *st)
 704 {
 705   if (verbose_option < 3)
 706     return;
 707
 708   /* selinux */
 709   if (selinux_context_option && st->cntx_name)
 710     fprintf (stdlis, "  s: %s\n", st->cntx_name);
 711
 712   /* acls */
 713   if (acls_option && (st->acls_a_len || st->acls_d_len))
 714     {
 715       fprintf (stdlis, "  a: ");
 716       acls_one_line ("", ',', st->acls_a_ptr, st->acls_a_len);
 717       acls_one_line ("default:", ',', st->acls_d_ptr, st->acls_d_len);
 718       fprintf (stdlis, "\n");
 719     }
 720
 721   /* xattrs */
 722   if (xattrs_option && st->xattr_map_size)
 723     {
 724       int i;
 725
 726       for (i = 0; i < st->xattr_map_size; ++i)
 727         {
 728           char *keyword = st->xattr_map[i].xkey + strlen ("SCHILY.xattr.");
 729           if (!xattrs_masked_out (keyword, false /* like extracting */ ))
 730             fprintf (stdlis, "  x: %lu %s\n",
 731                      (unsigned long) st->xattr_map[i].xval_len, keyword);
 732         }
 733     }
 734 }