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
34 #define ARRAY_SIZE(a) (sizeof(a) / sizeof((a)[0]))
35
alloc_mounted_path(const char * mount_point,const char * subpath,char ** mounted_path)36 void alloc_mounted_path(const char *mount_point, const char *subpath, char **mounted_path) {
37 *mounted_path = malloc(strlen(mount_point) + strlen(subpath) + 1);
38 if (*mounted_path == NULL) {
39 perror("Malloc Failure.");
40 exit(EXIT_FAILURE);
41 }
42 strcpy(*mounted_path, mount_point);
43 strcat(*mounted_path, subpath);
44 }
45
android_fs_config(fs_config_func_t fs_config_func,const char * path,struct stat * stat,const char * target_out_path,uint64_t * capabilities)46 void android_fs_config(fs_config_func_t fs_config_func, const char *path, struct stat *stat,
47 const char *target_out_path, uint64_t *capabilities) {
48 // filesystem_config does not preserve file type bits
49 mode_t stat_file_type_mask = stat->st_mode & S_IFMT;
50 unsigned int uid = 0, gid = 0, mode = 0;
51 if (fs_config_func) {
52 fs_config_func(path, S_ISDIR(stat->st_mode), target_out_path,
53 &uid, &gid, &mode, capabilities);
54 stat->st_uid = uid;
55 stat->st_gid = gid;
56 stat->st_mode = mode;
57 }
58 stat->st_mode |= stat_file_type_mask;
59 }
60
61
get_sehnd(const char * context_file)62 struct selabel_handle *get_sehnd(const char *context_file) {
63 struct selinux_opt seopts[] = {
64 {
65 .type = SELABEL_OPT_PATH,
66 .value = context_file
67 }
68 };
69 struct selabel_handle *sehnd =
70 selabel_open(SELABEL_CTX_FILE, seopts, ARRAY_SIZE(seopts));
71
72 if (!sehnd) {
73 perror("Error running selabel_open.");
74 exit(EXIT_FAILURE);
75 }
76 return sehnd;
77 }
78
79
set_selabel(const char * path,unsigned int mode,struct selabel_handle * sehnd)80 char *set_selabel(const char *path, unsigned int mode, struct selabel_handle *sehnd) {
81 char *secontext;
82 if (sehnd != NULL) {
83 int full_name_size = strlen(path) + 2;
84 char* full_name = (char*) malloc(full_name_size);
85 if (full_name == NULL) {
86 perror("Malloc Failure.");
87 exit(EXIT_FAILURE);
88 }
89
90 full_name[0] = '/';
91 strncpy(full_name + 1, path, full_name_size - 1);
92
93 if (selabel_lookup(sehnd, &secontext, full_name, mode)) {
94 secontext = strdup("u:object_r:unlabeled:s0");
95 }
96
97 free(full_name);
98 return secontext;
99 }
100 perror("Selabel handle is NULL.");
101 exit(EXIT_FAILURE);
102 }
103
set_caps(uint64_t capabilities)104 struct vfs_cap_data set_caps(uint64_t capabilities) {
105 struct vfs_cap_data cap_data;
106 memset(&cap_data, 0, sizeof(cap_data));
107
108 if (capabilities == 0)
109 return cap_data;
110
111 cap_data.magic_etc = VFS_CAP_REVISION | VFS_CAP_FLAGS_EFFECTIVE;
112 cap_data.data[0].permitted = (uint32_t) capabilities;
113 cap_data.data[0].inheritable = 0;
114 cap_data.data[1].permitted = (uint32_t) (capabilities >> 32);
115 cap_data.data[1].inheritable = 0;
116
117 return cap_data;
118 }
119