1 /*
2 * Copyright (C) 2015 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 /* This file is used to define the properties of the filesystem
18 ** images generated by build tools (mkbootfs and mkyaffs2image) and
19 ** by the device side of adb.
20 */
21
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <sys/stat.h>
26
27 #include <selinux/label.h>
28 #include <selinux/selinux.h>
29
30 #include "android.h"
31 #include "private/android_filesystem_config.h"
32 #include "private/canned_fs_config.h"
33 #include "private/fs_config.h"
34
35 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
36
alloc_mounted_path(const char * mount_point,const char * subpath,char ** mounted_path)37 void alloc_mounted_path(const char *mount_point, const char *subpath, char **mounted_path) {
38 *mounted_path = malloc(strlen(mount_point) + strlen(subpath) + 1);
39 if (*mounted_path == NULL) {
40 perror("Malloc Failure.");
41 exit(EXIT_FAILURE);
42 }
43 strcpy(*mounted_path, mount_point);
44 strcat(*mounted_path, subpath);
45 }
46
android_fs_config(fs_config_func_t fs_config_func,const char * path,struct stat * stat,const char * target_out_path,uint64_t * capabilities)47 void android_fs_config(fs_config_func_t fs_config_func, const char *path, struct stat *stat,
48 const char *target_out_path, uint64_t *capabilities) {
49 // filesystem_config does not preserve file type bits
50 mode_t stat_file_type_mask = stat->st_mode & S_IFMT;
51 unsigned int uid = 0, gid = 0, mode = 0;
52 if (fs_config_func) {
53 fs_config_func(path, S_ISDIR(stat->st_mode), target_out_path,
54 &uid, &gid, &mode, capabilities);
55 stat->st_uid = uid;
56 stat->st_gid = gid;
57 stat->st_mode = mode;
58 }
59 stat->st_mode |= stat_file_type_mask;
60 }
61
62
get_sehnd(const char * context_file)63 struct selabel_handle *get_sehnd(const char *context_file) {
64 struct selinux_opt seopts[] = {
65 {
66 .type = SELABEL_OPT_PATH,
67 .value = context_file
68 }
69 };
70 struct selabel_handle *sehnd =
71 selabel_open(SELABEL_CTX_FILE, seopts, ARRAY_SIZE(seopts));
72
73 if (!sehnd) {
74 perror("Error running selabel_open.");
75 exit(EXIT_FAILURE);
76 }
77 return sehnd;
78 }
79
80
set_selabel(const char * path,unsigned int mode,struct selabel_handle * sehnd)81 char *set_selabel(const char *path, unsigned int mode, struct selabel_handle *sehnd) {
82 char *secontext;
83 if (sehnd != NULL) {
84 int full_name_size = strlen(path) + 2;
85 char* full_name = (char*) malloc(full_name_size);
86 if (full_name == NULL) {
87 perror("Malloc Failure.");
88 exit(EXIT_FAILURE);
89 }
90
91 full_name[0] = '/';
92 strncpy(full_name + 1, path, full_name_size - 1);
93
94 if (selabel_lookup(sehnd, &secontext, full_name, mode)) {
95 secontext = strdup("u:object_r:unlabeled:s0");
96 }
97
98 free(full_name);
99 return secontext;
100 }
101 perror("Selabel handle is NULL.");
102 exit(EXIT_FAILURE);
103 }
104
set_caps(uint64_t capabilities)105 struct vfs_cap_data set_caps(uint64_t capabilities) {
106 struct vfs_cap_data cap_data;
107 memset(&cap_data, 0, sizeof(cap_data));
108
109 if (capabilities == 0)
110 return cap_data;
111
112 cap_data.magic_etc = VFS_CAP_REVISION_2 | VFS_CAP_FLAGS_EFFECTIVE;
113 cap_data.data[0].permitted = (uint32_t) capabilities;
114 cap_data.data[0].inheritable = 0;
115 cap_data.data[1].permitted = (uint32_t) (capabilities >> 32);
116 cap_data.data[1].inheritable = 0;
117
118 return cap_data;
119 }
120