lib/getfilecon.c

   1 /* wrap getfilecon, lgetfilecon, and fgetfilecon
   2    Copyright (C) 2009-2024 Free Software Foundation, Inc.
   3
   4    This file is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU Lesser General Public License as
   6    published by the Free Software Foundation; either version 2.1 of the
   7    License, or (at your option) any later version.
   8
   9    This file is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* written by Jim Meyering */
  18
  19 #include <config.h>
  20
  21 #include <selinux/selinux.h>
  22
  23 #include <sys/types.h>
  24 #include <errno.h>
  25 #include <string.h>
  26
  27 /* FIXME: remove this once there is an errno-gnu module
  28    that guarantees the definition of ENODATA.  */
  29 #ifndef ENODATA
  30 # define ENODATA ENOTSUP
  31 #endif
  32
  33 #undef getfilecon
  34 #undef getfilecon_raw
  35 #undef lgetfilecon
  36 #undef lgetfilecon_raw
  37 #undef fgetfilecon
  38 #undef fgetfilecon_raw
  39 int getfilecon (char const *file, char **con);
  40 int getfilecon_raw (char const *file, char **con);
  41 int lgetfilecon (char const *file, char **con);
  42 int lgetfilecon_raw (char const *file, char **con);
  43 int fgetfilecon (int fd, char **con);
  44 int fgetfilecon_raw (int fd, char **con);
  45
  46 /* getfilecon, lgetfilecon, and fgetfilecon can all misbehave, be it
  47    via an old version of libselinux where these would return 0 and set the
  48    result context to NULL, or via a modern kernel+lib operating on a file
  49    from a disk whose attributes were set by a kernel from around 2006.
  50    In that latter case, the functions return a length of 10 for the
  51    "unlabeled" context.  Map both failures to a return value of -1, and
  52    set errno to ENOTSUP in the first case, and ENODATA in the latter.  */
  53
  54 static int
  55 map_to_failure (int ret, char **con)
  56 {
  57   if (ret == 0)
  58     {
  59       errno = ENOTSUP;
  60       return -1;
  61     }
  62
  63   if (ret == 10 && strcmp (*con, "unlabeled") == 0)
  64     {
  65       freecon (*con);
  66       *con = NULL;
  67       errno = ENODATA;
  68       return -1;
  69     }
  70
  71   return ret;
  72 }
  73
  74 int
  75 rpl_getfilecon (char const *file, char **con)
  76 {
  77   int ret = getfilecon (file, con);
  78   return map_to_failure (ret, con);
  79 }
  80
  81 int
  82 rpl_getfilecon_raw (char const *file, char **con)
  83 {
  84   int ret = getfilecon_raw (file, con);
  85   return map_to_failure (ret, con);
  86 }
  87
  88 int
  89 rpl_lgetfilecon (char const *file, char **con)
  90 {
  91   int ret = lgetfilecon (file, con);
  92   return map_to_failure (ret, con);
  93 }
  94
  95 int
  96 rpl_lgetfilecon_raw (char const *file, char **con)
  97 {
  98   int ret = lgetfilecon_raw (file, con);
  99   return map_to_failure (ret, con);
 100 }
 101
 102 int
 103 rpl_fgetfilecon (int fd, char**con)
 104 {
 105   int ret = fgetfilecon (fd, con);
 106   return map_to_failure (ret, con);
 107 }
 108
 109 int
 110 rpl_fgetfilecon_raw (int fd, char**con)
 111 {
 112   int ret = fgetfilecon_raw (fd, con);
 113   return map_to_failure (ret, con);
 114 }