blob: 2e1d769d99d90e73bb4756891b77dcd4ffaf9da0 [file] [log] [blame]
bigbiff1f9e4842020-10-31 11:33:15 -04001/*
2 * Copyright (C) 2014 The Team Win Recovery 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/*
18 * The purpose of these functions is to try to get and set the proper
19 * file permissions, SELinux contexts, owner, and group so that these
20 * files are accessible when we boot up to normal Android via MTP and to
21 * file manager apps. During early boot we try to read the contexts and
22 * owner / group info from /data/media or from /data/media/0 and store
23 * them in static variables. From there, we'll try to set the same
24 * contexts, owner, and group information on most files we create during
25 * operations like backups, copying the log, and MTP operations.
26 */
27
28#include <sys/stat.h>
29#include <stdio.h>
30#include <unistd.h>
31#include "selinux/selinux.h"
32
33static security_context_t selinux_context;
34struct stat s;
35static int has_stat = 0;
36
37int tw_get_context(const char* filename) {
38 if (lgetfilecon(filename, &selinux_context) >= 0) {
39 printf("tw_get_context got selinux context: %s\n", selinux_context);
40 return 0;
41 } else {
42 printf("tw_get_context failed to get selinux context\n");
43 selinux_context = NULL;
44 }
45 return -1;
46}
47
48int tw_get_stat(const char* filename) {
49 if (lstat(filename, &s) == 0) {
50 has_stat = 1;
51 return 0;
52 }
53 printf("tw_get_stat failed to lstat '%s'\n", filename);
54 return -1;
55}
56
57int tw_get_default_metadata(const char* filename) {
58 if (tw_get_context(filename) == 0 && tw_get_stat(filename) == 0)
59 return 0;
60 return -1;
61}
62
63// Most of this logging is disabled to prevent log spam if we are trying
64// to set contexts and permissions on file systems that do not support
65// these types of things (e.g. vfat / FAT / FAT32).
66int tw_set_default_metadata(const char* filename) {
67 int ret = 0;
68 struct stat st;
69
70 if (selinux_context == NULL) {
71 //printf("selinux_context was null, '%s'\n", filename);
72 ret = -1;
73 } else if (lsetfilecon(filename, selinux_context) < 0) {
74 //printf("Failed to set default contexts on '%s'.\n", filename);
75 ret = -1;
76 }
77
78 if (lstat(filename, &st) == 0 && st.st_mode & S_IFREG && chmod(filename, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IROTH) < 0) {
79 //printf("Failed to chmod '%s'\n", filename);
80 ret = -1;
81 }
82
83 if (has_stat && chown(filename, s.st_uid, s.st_gid) < 0) {
84 //printf("Failed to lchown '%s'.\n", filename);
85 ret = -1;
86 }
87 //printf("Done trying to set defaults on '%s'\n");
88 return ret;
89}