1 /*
2 * Copyright (C) 2008 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include <stdio.h>
18 #include <stdlib.h>
19 #include <sys/stat.h>
20 #include <errno.h>
21 #include <unistd.h>
22 #include <string.h>
23 #include <inttypes.h>
24
25 #include <selinux/selinux.h>
26 #include <selinux/label.h>
27 #include <selinux/android.h>
28
29 #include "private/android_filesystem_config.h"
30
31 // This program takes a list of files and directories (indicated by a
32 // trailing slash) on the stdin, and prints to stdout each input
33 // filename along with its desired uid, gid, and mode (in octal).
34 // The leading slash should be stripped from the input.
35 //
36 // After the first 4 columns, optional key=value pairs are emitted
37 // for each file. Currently, the following keys are supported:
38 // * -S: selabel=[selinux_label]
39 // * -C: capabilities=[hex capabilities value]
40 //
41 // Example input:
42 //
43 // system/etc/dbus.conf
44 // data/app/
45 //
46 // Output:
47 //
48 // system/etc/dbus.conf 1002 1002 440
49 // data/app 1000 1000 771
50 //
51 // or if, for example, -S is used:
52 //
53 // system/etc/dbus.conf 1002 1002 440 selabel=u:object_r:system_file:s0
54 // data/app 1000 1000 771 selabel=u:object_r:apk_data_file:s0
55 //
56 // Note that the output will omit the trailing slash from
57 // directories.
58
get_sehnd(const char * context_file)59 static struct selabel_handle* get_sehnd(const char* context_file) {
60 struct selinux_opt seopts[] = { { SELABEL_OPT_PATH, context_file } };
61 struct selabel_handle* sehnd = selabel_open(SELABEL_CTX_FILE, seopts, 1);
62
63 if (!sehnd) {
64 perror("error running selabel_open");
65 exit(EXIT_FAILURE);
66 }
67 return sehnd;
68 }
69
usage()70 static void usage() {
71 fprintf(stderr, "Usage: fs_config [-S context_file] [-C]\n");
72 }
73
main(int argc,char ** argv)74 int main(int argc, char** argv) {
75 char buffer[1024];
76 const char* context_file = NULL;
77 struct selabel_handle* sehnd = NULL;
78 int print_capabilities = 0;
79 int opt;
80 while((opt = getopt(argc, argv, "CS:")) != -1) {
81 switch(opt) {
82 case 'C':
83 print_capabilities = 1;
84 break;
85 case 'S':
86 context_file = optarg;
87 break;
88 default:
89 usage();
90 exit(EXIT_FAILURE);
91 }
92 }
93
94 if (context_file != NULL) {
95 sehnd = get_sehnd(context_file);
96 }
97
98 while (fgets(buffer, 1023, stdin) != NULL) {
99 int is_dir = 0;
100 int i;
101 for (i = 0; i < 1024 && buffer[i]; ++i) {
102 switch (buffer[i]) {
103 case '\n':
104 buffer[i-is_dir] = '\0';
105 i = 1025;
106 break;
107 case '/':
108 is_dir = 1;
109 break;
110 default:
111 is_dir = 0;
112 break;
113 }
114 }
115
116 unsigned uid = 0, gid = 0, mode = 0;
117 uint64_t capabilities;
118 fs_config(buffer, is_dir, &uid, &gid, &mode, &capabilities);
119 printf("%s %d %d %o", buffer, uid, gid, mode);
120
121 if (sehnd != NULL) {
122 size_t buffer_strlen = strnlen(buffer, sizeof(buffer));
123 if (buffer_strlen >= sizeof(buffer)) {
124 fprintf(stderr, "non null terminated buffer, aborting\n");
125 exit(EXIT_FAILURE);
126 }
127 size_t full_name_size = buffer_strlen + 2;
128 char* full_name = (char*) malloc(full_name_size);
129 if (full_name == NULL) {
130 perror("malloc");
131 exit(EXIT_FAILURE);
132 }
133
134 full_name[0] = '/';
135 strncpy(full_name + 1, buffer, full_name_size - 1);
136 full_name[full_name_size - 1] = '\0';
137
138 char* secontext;
139 if (selabel_lookup(sehnd, &secontext, full_name, ( mode | (is_dir ? S_IFDIR : S_IFREG)))) {
140 secontext = strdup("u:object_r:unlabeled:s0");
141 }
142
143 printf(" selabel=%s", secontext);
144 free(full_name);
145 freecon(secontext);
146 }
147
148 if (print_capabilities) {
149 printf(" capabilities=0x%" PRIx64, capabilities);
150 }
151
152 printf("\n");
153 }
154 return 0;
155 }
156