1 /* wrap getfilecon, lgetfilecon, and fgetfilecon
2    Copyright (C) 2009-2021 Free Software Foundation, Inc.
3 
4    This program is free software; you can redistribute it and/or modify
5    it under the terms of the GNU General Public License as published by
6    the Free Software Foundation; either version 3, or (at your option)
7    any later version.
8 
9    This program 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 General Public License for more details.
13 
14    You should have received a copy of the GNU 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 lgetfilecon
35 #undef fgetfilecon
36 int getfilecon (char const *file, char **con);
37 int lgetfilecon (char const *file, char **con);
38 int fgetfilecon (int fd, char **con);
39 
40 /* getfilecon, lgetfilecon, and fgetfilecon can all misbehave, be it
41    via an old version of libselinux where these would return 0 and set the
42    result context to NULL, or via a modern kernel+lib operating on a file
43    from a disk whose attributes were set by a kernel from around 2006.
44    In that latter case, the functions return a length of 10 for the
45    "unlabeled" context.  Map both failures to a return value of -1, and
46    set errno to ENOTSUP in the first case, and ENODATA in the latter.  */
47 
48 static int
map_to_failure(int ret,char ** con)49 map_to_failure (int ret, char **con)
50 {
51   if (ret == 0)
52     {
53       errno = ENOTSUP;
54       return -1;
55     }
56 
57   if (ret == 10 && strcmp (*con, "unlabeled") == 0)
58     {
59       freecon (*con);
60       *con = NULL;
61       errno = ENODATA;
62       return -1;
63     }
64 
65   return ret;
66 }
67 
68 int
rpl_getfilecon(char const * file,char ** con)69 rpl_getfilecon (char const *file, char **con)
70 {
71   int ret = getfilecon (file, con);
72   return map_to_failure (ret, con);
73 }
74 
75 int
rpl_lgetfilecon(char const * file,char ** con)76 rpl_lgetfilecon (char const *file, char **con)
77 {
78   int ret = lgetfilecon (file, con);
79   return map_to_failure (ret, con);
80 }
81 
82 int
rpl_fgetfilecon(int fd,char ** con)83 rpl_fgetfilecon (int fd, char**con)
84 {
85   int ret = fgetfilecon (fd, con);
86   return map_to_failure (ret, con);
87 }
88