Fix CVE-2018-20482
[tar.git] / src / xattrs.c
blob9e1ddb1dceb0aabaace86a250e35cc670f5b58ff
1 /* Support for extended attributes.
3 Copyright (C) 2006-2014, 2016-2017 Free Software Foundation, Inc.
5 This file is part of GNU tar.
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.
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.
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/>.
20 Written by James Antill, on 2006-07-27. */
22 #include <config.h>
23 #include <system.h>
25 #include <fnmatch.h>
26 #include <quotearg.h>
28 #include "common.h"
30 #include "xattr-at.h"
31 #include "selinux-at.h"
33 struct xattrs_mask_map
35 const char **masks;
36 size_t size;
37 size_t used;
40 /* list of fnmatch patterns */
41 static struct
43 /* lists of fnmatch patterns */
44 struct xattrs_mask_map incl;
45 struct xattrs_mask_map excl;
46 } xattrs_setup;
48 /* disable posix acls when problem found in gnulib script m4/acl.m4 */
49 #if ! USE_ACL
50 # undef HAVE_POSIX_ACLS
51 #endif
53 #ifdef HAVE_POSIX_ACLS
54 # include "acl.h"
55 # include <sys/acl.h>
56 #endif
58 #ifdef HAVE_POSIX_ACLS
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 static int acl_delete_def_file_at (int, char const *);
66 /* acl_get_file_at */
67 #define AT_FUNC_NAME acl_get_file_at
68 #define AT_FUNC_RESULT acl_t
69 #define AT_FUNC_FAIL (acl_t)NULL
70 #define AT_FUNC_F1 acl_get_file
71 #define AT_FUNC_POST_FILE_PARAM_DECLS , acl_type_t type
72 #define AT_FUNC_POST_FILE_ARGS , type
73 #include "at-func.c"
74 #undef AT_FUNC_NAME
75 #undef AT_FUNC_F1
76 #undef AT_FUNC_RESULT
77 #undef AT_FUNC_FAIL
78 #undef AT_FUNC_POST_FILE_PARAM_DECLS
79 #undef AT_FUNC_POST_FILE_ARGS
81 /* acl_set_file_at */
82 #define AT_FUNC_NAME acl_set_file_at
83 #define AT_FUNC_F1 acl_set_file
84 #define AT_FUNC_POST_FILE_PARAM_DECLS , acl_type_t type, acl_t acl
85 #define AT_FUNC_POST_FILE_ARGS , type, acl
86 #include "at-func.c"
87 #undef AT_FUNC_NAME
88 #undef AT_FUNC_F1
89 #undef AT_FUNC_POST_FILE_PARAM_DECLS
90 #undef AT_FUNC_POST_FILE_ARGS
92 /* acl_delete_def_file_at */
93 #define AT_FUNC_NAME acl_delete_def_file_at
94 #define AT_FUNC_F1 acl_delete_def_file
95 #define AT_FUNC_POST_FILE_PARAM_DECLS
96 #define AT_FUNC_POST_FILE_ARGS
97 #include "at-func.c"
98 #undef AT_FUNC_NAME
99 #undef AT_FUNC_F1
100 #undef AT_FUNC_POST_FILE_PARAM_DECLS
101 #undef AT_FUNC_POST_FILE_ARGS
103 /* gnulib file_has_acl_at */
104 #define AT_FUNC_NAME file_has_acl_at
105 #define AT_FUNC_F1 file_has_acl
106 #define AT_FUNC_POST_FILE_PARAM_DECLS , struct stat const *st
107 #define AT_FUNC_POST_FILE_ARGS , st
108 #include "at-func.c"
109 #undef AT_FUNC_NAME
110 #undef AT_FUNC_F1
111 #undef AT_FUNC_POST_FILE_PARAM_DECLS
112 #undef AT_FUNC_POST_FILE_ARGS
114 /* convert unix permissions into an ACL ... needed due to "default" ACLs */
115 static acl_t
116 perms2acl (int perms)
118 char val[] = "user::---,group::---,other::---";
119 /* 0123456789 123456789 123456789 123456789 */
121 /* user */
122 if (perms & 0400)
123 val[6] = 'r';
124 if (perms & 0200)
125 val[7] = 'w';
126 if (perms & 0100)
127 val[8] = 'x';
129 /* group */
130 if (perms & 0040)
131 val[17] = 'r';
132 if (perms & 0020)
133 val[18] = 'w';
134 if (perms & 0010)
135 val[19] = 'x';
137 /* other */
138 if (perms & 0004)
139 val[28] = 'r';
140 if (perms & 0002)
141 val[29] = 'w';
142 if (perms & 0001)
143 val[30] = 'x';
145 return acl_from_text (val);
148 static char *
149 skip_to_ext_fields (char *ptr)
151 /* skip tag name (user/group/default/mask) */
152 ptr += strcspn (ptr, ":,\n");
154 if (*ptr != ':')
155 return ptr;
156 ++ptr;
158 ptr += strcspn (ptr, ":,\n"); /* skip user/group name */
160 if (*ptr != ':')
161 return ptr;
162 ++ptr;
164 ptr += strcspn (ptr, ":,\n"); /* skip perms */
166 return ptr;
169 /* The POSIX draft allows extra fields after the three main ones. Star
170 uses this to add a fourth field for user/group which is the numeric ID.
171 This function removes such extra fields by overwriting them with the
172 characters that follow. */
173 static char *
174 fixup_extra_acl_fields (char *ptr)
176 char *src = ptr;
177 char *dst = ptr;
179 while (*src)
181 const char *old = src;
182 size_t len = 0;
184 src = skip_to_ext_fields (src);
185 len = src - old;
186 if (old != dst)
187 memmove (dst, old, len);
188 dst += len;
190 if (*src == ':') /* We have extra fields, skip them all */
191 src += strcspn (src, "\n,");
193 if ((*src == '\n') || (*src == ','))
194 *dst++ = *src++; /* also done when dst == src, but that's ok */
196 if (src != dst)
197 *dst = 0;
199 return ptr;
202 /* Set the "system.posix_acl_access/system.posix_acl_default" extended
203 attribute. Called only when acls_option > 0. */
204 static void
205 xattrs__acls_set (struct tar_stat_info const *st,
206 char const *file_name, int type,
207 char *ptr, size_t len, bool def)
209 acl_t acl;
211 if (ptr)
213 /* assert (strlen (ptr) == len); */
214 ptr = fixup_extra_acl_fields (ptr);
215 acl = acl_from_text (ptr);
217 else if (def)
219 /* No "default" IEEE 1003.1e ACL set for directory. At this moment,
220 FILE_NAME may already have inherited default acls from parent
221 directory; clean them up. */
222 if (acl_delete_def_file_at (chdir_fd, file_name))
223 WARNOPT (WARN_XATTR_WRITE,
224 (0, errno,
225 _("acl_delete_def_file_at: Cannot drop default POSIX ACLs "
226 "for file '%s'"),
227 file_name));
228 return;
230 else
231 acl = perms2acl (st->stat.st_mode);
233 if (!acl)
235 call_arg_warn ("acl_from_text", file_name);
236 return;
239 if (acl_set_file_at (chdir_fd, file_name, type, acl) == -1)
240 /* warn even if filesystem does not support acls */
241 WARNOPT (WARN_XATTR_WRITE,
242 (0, errno,
243 _ ("acl_set_file_at: Cannot set POSIX ACLs for file '%s'"),
244 file_name));
246 acl_free (acl);
249 /* Cleanup textual representation of the ACL in VAL by eliminating tab
250 characters and comments */
251 static void
252 xattrs_acls_cleanup (char *val, size_t *plen)
254 char *p, *q;
256 p = q = val + strcspn (val, "#\t");
257 while (*q)
259 if (*q == '\t')
260 q++;
261 else if (*q == '#')
263 while (*q != '\n')
264 q++;
266 else
267 *p++ = *q++;
269 *plen = p - val;
270 *p++ = 0;
273 static void
274 xattrs__acls_get_a (int parentfd, const char *file_name,
275 struct tar_stat_info *st,
276 char **ret_ptr, size_t * ret_len)
278 char *val = NULL;
279 acl_t acl;
281 if (!(acl = acl_get_file_at (parentfd, file_name, ACL_TYPE_ACCESS)))
283 if (errno != ENOTSUP)
284 call_arg_warn ("acl_get_file_at", file_name);
285 return;
288 val = acl_to_text (acl, NULL);
289 acl_free (acl);
291 if (!val)
293 call_arg_warn ("acl_to_text", file_name);
294 return;
297 *ret_ptr = xstrdup (val);
298 xattrs_acls_cleanup (*ret_ptr, ret_len);
299 acl_free (val);
302 /* "system.posix_acl_default" */
303 static void
304 xattrs__acls_get_d (int parentfd, char const *file_name,
305 struct tar_stat_info *st,
306 char **ret_ptr, size_t * ret_len)
308 char *val = NULL;
309 acl_t acl;
311 if (!(acl = acl_get_file_at (parentfd, file_name, ACL_TYPE_DEFAULT)))
313 if (errno != ENOTSUP)
314 call_arg_warn ("acl_get_file_at", file_name);
315 return;
318 val = acl_to_text (acl, NULL);
319 acl_free (acl);
321 if (!val)
323 call_arg_warn ("acl_to_text", file_name);
324 return;
327 *ret_ptr = xstrdup (val);
328 xattrs_acls_cleanup (*ret_ptr, ret_len);
329 acl_free (val);
331 #endif /* HAVE_POSIX_ACLS */
333 static void
334 acls_one_line (const char *prefix, char delim,
335 const char *aclstring, size_t len)
337 /* support both long and short text representation of posix acls */
338 struct obstack stk;
339 int pref_len = strlen (prefix);
340 const char *oldstring = aclstring;
341 int pos = 0;
343 if (!aclstring || !len)
344 return;
346 obstack_init (&stk);
347 while (pos <= len)
349 int move = strcspn (aclstring, ",\n");
350 if (!move)
351 break;
353 if (oldstring != aclstring)
354 obstack_1grow (&stk, delim);
356 obstack_grow (&stk, prefix, pref_len);
357 obstack_grow (&stk, aclstring, move);
359 pos += move + 1;
360 aclstring += move + 1;
363 obstack_1grow (&stk, '\0');
365 fprintf (stdlis, "%s", (char *) obstack_finish (&stk));
367 obstack_free (&stk, NULL);
370 void
371 xattrs_acls_get (int parentfd, char const *file_name,
372 struct tar_stat_info *st, int fd, int xisfile)
374 if (acls_option > 0)
376 #ifndef HAVE_POSIX_ACLS
377 static int done = 0;
378 if (!done)
379 WARN ((0, 0, _("POSIX ACL support is not available")));
380 done = 1;
381 #else
382 int err = file_has_acl_at (parentfd, file_name, &st->stat);
383 if (err == 0)
384 return;
385 if (err == -1)
387 call_arg_warn ("file_has_acl_at", file_name);
388 return;
391 xattrs__acls_get_a (parentfd, file_name, st,
392 &st->acls_a_ptr, &st->acls_a_len);
393 if (!xisfile)
394 xattrs__acls_get_d (parentfd, file_name, st,
395 &st->acls_d_ptr, &st->acls_d_len);
396 #endif
400 void
401 xattrs_acls_set (struct tar_stat_info const *st,
402 char const *file_name, char typeflag)
404 if (acls_option > 0 && typeflag != SYMTYPE)
406 #ifndef HAVE_POSIX_ACLS
407 static int done = 0;
408 if (!done)
409 WARN ((0, 0, _("POSIX ACL support is not available")));
410 done = 1;
411 #else
412 xattrs__acls_set (st, file_name, ACL_TYPE_ACCESS,
413 st->acls_a_ptr, st->acls_a_len, false);
414 if (typeflag == DIRTYPE || typeflag == GNUTYPE_DUMPDIR)
415 xattrs__acls_set (st, file_name, ACL_TYPE_DEFAULT,
416 st->acls_d_ptr, st->acls_d_len, true);
417 #endif
421 static void
422 mask_map_realloc (struct xattrs_mask_map *map)
424 if (map->used == map->size)
426 if (map->size == 0)
427 map->size = 4;
428 map->masks = x2nrealloc (map->masks, &map->size, sizeof (map->masks[0]));
432 void
433 xattrs_mask_add (const char *mask, bool incl)
435 struct xattrs_mask_map *mask_map =
436 incl ? &xattrs_setup.incl : &xattrs_setup.excl;
437 /* ensure there is enough space */
438 mask_map_realloc (mask_map);
439 /* just assign pointers -- we silently expect that pointer "mask" is valid
440 through the whole program (pointer to argv array) */
441 mask_map->masks[mask_map->used++] = mask;
444 static void
445 clear_mask_map (struct xattrs_mask_map *mask_map)
447 if (mask_map->size)
448 free (mask_map->masks);
451 void
452 xattrs_clear_setup (void)
454 clear_mask_map (&xattrs_setup.incl);
455 clear_mask_map (&xattrs_setup.excl);
458 static bool xattrs_masked_out (const char *kw, bool archiving);
460 /* get xattrs from file given by FILE_NAME or FD (when non-zero)
461 xattrs are checked against the user supplied include/exclude mask
462 if no mask is given this includes all the user.*, security.*, system.*,
463 etc. available domains */
464 void
465 xattrs_xattrs_get (int parentfd, char const *file_name,
466 struct tar_stat_info *st, int fd)
468 if (xattrs_option > 0)
470 #ifndef HAVE_XATTRS
471 static int done = 0;
472 if (!done)
473 WARN ((0, 0, _("XATTR support is not available")));
474 done = 1;
475 #else
476 static size_t xsz = 1024;
477 static char *xatrs = NULL;
478 ssize_t xret = -1;
480 if (!xatrs)
481 xatrs = x2nrealloc (xatrs, &xsz, 1);
483 while (((fd == 0) ?
484 ((xret =
485 llistxattrat (parentfd, file_name, xatrs, xsz)) == -1) :
486 ((xret = flistxattr (fd, xatrs, xsz)) == -1))
487 && (errno == ERANGE))
489 xatrs = x2nrealloc (xatrs, &xsz, 1);
492 if (xret == -1)
493 call_arg_warn ((fd == 0) ? "llistxattrat" : "flistxattr", file_name);
494 else
496 const char *attr = xatrs;
497 static size_t asz = 1024;
498 static char *val = NULL;
500 if (!val)
501 val = x2nrealloc (val, &asz, 1);
503 while (xret > 0)
505 size_t len = strlen (attr);
506 ssize_t aret = 0;
508 while (((fd == 0)
509 ? ((aret = lgetxattrat (parentfd, file_name, attr,
510 val, asz)) == -1)
511 : ((aret = fgetxattr (fd, attr, val, asz)) == -1))
512 && (errno == ERANGE))
514 val = x2nrealloc (val, &asz, 1);
517 if (aret != -1)
519 if (!xattrs_masked_out (attr, true))
520 xheader_xattr_add (st, attr, val, aret);
522 else if (errno != ENOATTR)
523 call_arg_warn ((fd == 0) ? "lgetxattrat"
524 : "fgetxattr", file_name);
526 attr += len + 1;
527 xret -= len + 1;
530 #endif
534 #ifdef HAVE_XATTRS
535 static void
536 xattrs__fd_set (struct tar_stat_info const *st,
537 char const *file_name, char typeflag,
538 const char *attr, const char *ptr, size_t len)
540 if (ptr)
542 const char *sysname = "setxattrat";
543 int ret = -1;
545 if (typeflag != SYMTYPE)
546 ret = setxattrat (chdir_fd, file_name, attr, ptr, len, 0);
547 else
549 sysname = "lsetxattr";
550 ret = lsetxattrat (chdir_fd, file_name, attr, ptr, len, 0);
553 if (ret == -1)
554 WARNOPT (WARN_XATTR_WRITE,
555 (0, errno,
556 _("%s: Cannot set '%s' extended attribute for file '%s'"),
557 sysname, attr, file_name));
560 #endif
562 /* lgetfileconat is called against FILE_NAME iff the FD parameter is set to
563 zero, otherwise the fgetfileconat is used against correct file descriptor */
564 void
565 xattrs_selinux_get (int parentfd, char const *file_name,
566 struct tar_stat_info *st, int fd)
568 if (selinux_context_option > 0)
570 #if HAVE_SELINUX_SELINUX_H != 1
571 static int done = 0;
572 if (!done)
573 WARN ((0, 0, _("SELinux support is not available")));
574 done = 1;
575 #else
576 int result = fd ?
577 fgetfilecon (fd, &st->cntx_name)
578 : lgetfileconat (parentfd, file_name, &st->cntx_name);
580 if (result == -1 && errno != ENODATA && errno != ENOTSUP)
581 call_arg_warn (fd ? "fgetfilecon" : "lgetfileconat", file_name);
582 #endif
586 void
587 xattrs_selinux_set (struct tar_stat_info const *st,
588 char const *file_name, char typeflag)
590 if (selinux_context_option > 0)
592 #if HAVE_SELINUX_SELINUX_H != 1
593 static int done = 0;
594 if (!done)
595 WARN ((0, 0, _("SELinux support is not available")));
596 done = 1;
597 #else
598 const char *sysname = "setfilecon";
599 int ret;
601 if (!st->cntx_name)
602 return;
604 if (typeflag != SYMTYPE)
606 ret = setfileconat (chdir_fd, file_name, st->cntx_name);
607 sysname = "setfileconat";
609 else
611 ret = lsetfileconat (chdir_fd, file_name, st->cntx_name);
612 sysname = "lsetfileconat";
615 if (ret == -1)
616 WARNOPT (WARN_XATTR_WRITE,
617 (0, errno,
618 _("%s: Cannot set SELinux context for file '%s'"),
619 sysname, file_name));
620 #endif
624 static bool
625 xattrs_matches_mask (const char *kw, struct xattrs_mask_map *mm)
627 int i;
629 if (!mm->size)
630 return false;
632 for (i = 0; i < mm->used; i++)
633 if (fnmatch (mm->masks[i], kw, 0) == 0)
634 return true;
636 return false;
639 #define USER_DOT_PFX "user."
641 static bool
642 xattrs_kw_included (const char *kw, bool archiving)
644 if (xattrs_setup.incl.size)
645 return xattrs_matches_mask (kw, &xattrs_setup.incl);
646 else if (archiving)
647 return true;
648 else
649 return strncmp (kw, USER_DOT_PFX, sizeof (USER_DOT_PFX) - 1) == 0;
652 static bool
653 xattrs_kw_excluded (const char *kw, bool archiving)
655 return xattrs_setup.excl.size ?
656 xattrs_matches_mask (kw, &xattrs_setup.excl) : false;
659 /* Check whether the xattr with keyword KW should be discarded from list of
660 attributes that are going to be archived/excluded (set ARCHIVING=true for
661 archiving, false for excluding) */
662 static bool
663 xattrs_masked_out (const char *kw, bool archiving)
665 return xattrs_kw_included (kw, archiving) ?
666 xattrs_kw_excluded (kw, archiving) : true;
669 void
670 xattrs_xattrs_set (struct tar_stat_info const *st,
671 char const *file_name, char typeflag, int later_run)
673 if (xattrs_option > 0)
675 #ifndef HAVE_XATTRS
676 static int done = 0;
677 if (!done)
678 WARN ((0, 0, _("XATTR support is not available")));
679 done = 1;
680 #else
681 size_t scan = 0;
683 if (!st->xattr_map_size)
684 return;
686 for (; scan < st->xattr_map_size; ++scan)
688 char *keyword = st->xattr_map[scan].xkey;
689 keyword += strlen ("SCHILY.xattr.");
691 /* TODO: this 'later_run' workaround is temporary solution -> once
692 capabilities should become fully supported by it's API and there
693 should exist something like xattrs_capabilities_set() call.
694 For a regular files: all extended attributes are restored during
695 the first run except 'security.capability' which is restored in
696 'later_run == 1'. */
697 if (typeflag == REGTYPE
698 && later_run == !!strcmp (keyword, "security.capability"))
699 continue;
701 if (xattrs_masked_out (keyword, false /* extracting */ ))
702 /* we don't want to restore this keyword */
703 continue;
705 xattrs__fd_set (st, file_name, typeflag, keyword,
706 st->xattr_map[scan].xval_ptr,
707 st->xattr_map[scan].xval_len);
709 #endif
713 void
714 xattrs_print_char (struct tar_stat_info const *st, char *output)
716 int i;
718 if (verbose_option < 2)
720 *output = 0;
721 return;
724 if (xattrs_option > 0 || selinux_context_option > 0 || acls_option > 0)
726 /* placeholders */
727 *output = ' ';
728 output[1] = 0;
731 if (xattrs_option > 0 && st->xattr_map_size)
732 for (i = 0; i < st->xattr_map_size; ++i)
734 char *keyword = st->xattr_map[i].xkey + strlen ("SCHILY.xattr.");
735 if (!xattrs_masked_out (keyword, false /* like extracting */ ))
737 *output = '*';
738 break;
742 if (selinux_context_option > 0 && st->cntx_name)
743 *output = '.';
745 if (acls_option > 0 && (st->acls_a_len || st->acls_d_len))
746 *output = '+';
749 void
750 xattrs_print (struct tar_stat_info const *st)
752 if (verbose_option < 3)
753 return;
755 /* selinux */
756 if (selinux_context_option > 0 && st->cntx_name)
757 fprintf (stdlis, " s: %s\n", st->cntx_name);
759 /* acls */
760 if (acls_option > 0 && (st->acls_a_len || st->acls_d_len))
762 fprintf (stdlis, " a: ");
763 acls_one_line ("", ',', st->acls_a_ptr, st->acls_a_len);
764 if (st->acls_a_len && st->acls_d_len)
765 fprintf (stdlis, ",");
766 acls_one_line ("default:", ',', st->acls_d_ptr, st->acls_d_len);
767 fprintf (stdlis, "\n");
770 /* xattrs */
771 if (xattrs_option > 0 && st->xattr_map_size)
773 int i;
775 for (i = 0; i < st->xattr_map_size; ++i)
777 char *keyword = st->xattr_map[i].xkey + strlen ("SCHILY.xattr.");
778 if (!xattrs_masked_out (keyword, false /* like extracting */ ))
779 fprintf (stdlis, " x: %lu %s\n",
780 (unsigned long) st->xattr_map[i].xval_len, keyword);