1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
|
/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/* This file is used to define the properties of the filesystem
** images generated by build tools (mkbootfs and mkyaffs2image) and
** by the device side of adb.
*/
#define LOG_TAG "fs_config"
#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <log/log.h>
#include <private/android_filesystem_config.h>
#include <utils/Compat.h>
#ifndef O_BINARY
#define O_BINARY 0
#endif
/* The following structure is stored little endian */
struct fs_path_config_from_file {
uint16_t len;
uint16_t mode;
uint16_t uid;
uint16_t gid;
uint64_t capabilities;
char prefix[];
} __attribute__((__aligned__(sizeof(uint64_t))));
/* My kingdom for <endian.h> */
static inline uint16_t get2LE(const uint8_t* src)
{
return src[0] | (src[1] << 8);
}
static inline uint64_t get8LE(const uint8_t* src)
{
uint32_t low, high;
low = src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
high = src[4] | (src[5] << 8) | (src[6] << 16) | (src[7] << 24);
return ((uint64_t) high << 32) | (uint64_t) low;
}
#define ALIGN(x, alignment) ( ((x) + ((alignment) - 1)) & ~((alignment) - 1) )
/* Rules for directories.
** These rules are applied based on "first match", so they
** should start with the most specific path and work their
** way up to the root.
*/
static const struct fs_path_config android_dirs[] = {
{ 00770, AID_SYSTEM, AID_CACHE, 0, "cache" },
{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app" },
{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private" },
{ 00771, AID_ROOT, AID_ROOT, 0, "data/dalvik-cache" },
{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/data" },
{ 00771, AID_SHELL, AID_SHELL, 0, "data/local/tmp" },
{ 00771, AID_SHELL, AID_SHELL, 0, "data/local" },
{ 01771, AID_SYSTEM, AID_MISC, 0, "data/misc" },
{ 00770, AID_DHCP, AID_DHCP, 0, "data/misc/dhcp" },
{ 00771, AID_SHARED_RELRO, AID_SHARED_RELRO, 0, "data/misc/shared_relro" },
{ 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media" },
{ 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/Music" },
{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data" },
{ 00750, AID_ROOT, AID_SHELL, 0, "sbin" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/bin" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/vendor" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/xbin" },
{ 00755, AID_ROOT, AID_ROOT, 0, "system/etc/ppp" },
{ 00755, AID_ROOT, AID_SHELL, 0, "vendor" },
{ 00777, AID_ROOT, AID_ROOT, 0, "sdcard" },
{ 00755, AID_ROOT, AID_ROOT, 0, 0 },
};
/* Rules for files.
** These rules are applied based on "first match", so they
** should start with the most specific path and work their
** way up to the root. Prefixes ending in * denotes wildcard
** and will allow partial matches.
*/
static const char conf_dir[] = "/system/etc/fs_config_dirs";
static const char conf_file[] = "/system/etc/fs_config_files";
static const struct fs_path_config android_files[] = {
{ 00440, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.rc" },
{ 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.sh" },
{ 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.ril" },
{ 00550, AID_DHCP, AID_SHELL, 0, "system/etc/dhcpcd/dhcpcd-run-hooks" },
{ 00555, AID_ROOT, AID_ROOT, 0, "system/etc/ppp/*" },
{ 00555, AID_ROOT, AID_ROOT, 0, "system/etc/rc.*" },
{ 00444, AID_ROOT, AID_ROOT, 0, conf_dir + 1 },
{ 00444, AID_ROOT, AID_ROOT, 0, conf_file + 1 },
{ 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app/*" },
{ 00644, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/*" },
{ 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private/*" },
{ 00644, AID_APP, AID_APP, 0, "data/data/*" },
/* the following five files are INTENTIONALLY set-uid, but they
* are NOT included on user builds. */
{ 04750, AID_ROOT, AID_SHELL, 0, "system/xbin/su" },
{ 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/librank" },
{ 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/procrank" },
{ 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/procmem" },
{ 04770, AID_ROOT, AID_RADIO, 0, "system/bin/pppd-ril" },
/* the following files have enhanced capabilities and ARE included in user builds. */
{ 00750, AID_ROOT, AID_SHELL, (1ULL << CAP_SETUID) | (1ULL << CAP_SETGID), "system/bin/run-as" },
{ 00700, AID_SYSTEM, AID_SHELL, (1ULL << CAP_BLOCK_SUSPEND), "system/bin/inputflinger" },
{ 00750, AID_ROOT, AID_ROOT, 0, "system/bin/uncrypt" },
{ 00750, AID_ROOT, AID_ROOT, 0, "system/bin/install-recovery.sh" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/bin/*" },
{ 00755, AID_ROOT, AID_ROOT, 0, "system/lib/valgrind/*" },
{ 00755, AID_ROOT, AID_ROOT, 0, "system/lib64/valgrind/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/xbin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/vendor/bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "vendor/bin/*" },
{ 00750, AID_ROOT, AID_SHELL, 0, "sbin/*" },
{ 00755, AID_ROOT, AID_ROOT, 0, "bin/*" },
{ 00750, AID_ROOT, AID_SHELL, 0, "init*" },
{ 00750, AID_ROOT, AID_SHELL, 0, "sbin/fs_mgr" },
{ 00640, AID_ROOT, AID_SHELL, 0, "fstab.*" },
{ 00644, AID_ROOT, AID_ROOT, 0, 0 },
};
static int fs_config_open(int dir)
{
int fd = -1;
const char *out = getenv("OUT");
if (out && *out) {
char *name = NULL;
asprintf(&name, "%s%s", out, dir ? conf_dir : conf_file);
if (name) {
fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY | O_BINARY));
free(name);
}
}
if (fd < 0) {
fd = TEMP_FAILURE_RETRY(open(dir ? conf_dir : conf_file, O_RDONLY | O_BINARY));
}
return fd;
}
static bool fs_config_cmp(bool dir, const char *prefix, size_t len,
const char *path, size_t plen)
{
if (dir) {
if (plen < len) {
return false;
}
} else {
/* If name ends in * then allow partial matches. */
if (prefix[len - 1] == '*') {
return !strncmp(prefix, path, len - 1);
}
if (plen != len) {
return false;
}
}
return !strncmp(prefix, path, len);
}
void fs_config(const char *path, int dir,
unsigned *uid, unsigned *gid, unsigned *mode, uint64_t *capabilities)
{
const struct fs_path_config *pc;
int fd, plen;
if (path[0] == '/') {
path++;
}
plen = strlen(path);
fd = fs_config_open(dir);
if (fd >= 0) {
struct fs_path_config_from_file header;
while (TEMP_FAILURE_RETRY(read(fd, &header, sizeof(header))) == sizeof(header)) {
char *prefix;
uint16_t host_len = get2LE((const uint8_t *)&header.len);
ssize_t len, remainder = host_len - sizeof(header);
if (remainder <= 0) {
ALOGE("%s len is corrupted", dir ? conf_dir : conf_file);
break;
}
prefix = calloc(1, remainder);
if (!prefix) {
ALOGE("%s out of memory", dir ? conf_dir : conf_file);
break;
}
if (TEMP_FAILURE_RETRY(read(fd, prefix, remainder)) != remainder) {
free(prefix);
ALOGE("%s prefix is truncated", dir ? conf_dir : conf_file);
break;
}
len = strnlen(prefix, remainder);
if (len >= remainder) { /* missing a terminating null */
free(prefix);
ALOGE("%s is corrupted", dir ? conf_dir : conf_file);
break;
}
if (fs_config_cmp(dir, prefix, len, path, plen)) {
free(prefix);
close(fd);
*uid = get2LE((const uint8_t *)&(header.uid));
*gid = get2LE((const uint8_t *)&(header.gid));
*mode = (*mode & (~07777)) | get2LE((const uint8_t *)&(header.mode));
*capabilities = get8LE((const uint8_t *)&(header.capabilities));
return;
}
free(prefix);
}
close(fd);
}
pc = dir ? android_dirs : android_files;
for(; pc->prefix; pc++){
if (fs_config_cmp(dir, pc->prefix, strlen(pc->prefix), path, plen)) {
break;
}
}
*uid = pc->uid;
*gid = pc->gid;
*mode = (*mode & (~07777)) | pc->mode;
*capabilities = pc->capabilities;
}
ssize_t fs_config_generate(char *buffer, size_t length, const struct fs_path_config *pc)
{
struct fs_path_config_from_file *p = (struct fs_path_config_from_file *)buffer;
size_t len = ALIGN(sizeof(*p) + strlen(pc->prefix) + 1, sizeof(uint64_t));
if ((length < len) || (len > UINT16_MAX)) {
return -ENOSPC;
}
memset(p, 0, len);
uint16_t host_len = len;
p->len = get2LE((const uint8_t *)&host_len);
p->mode = get2LE((const uint8_t *)&(pc->mode));
p->uid = get2LE((const uint8_t *)&(pc->uid));
p->gid = get2LE((const uint8_t *)&(pc->gid));
p->capabilities = get8LE((const uint8_t *)&(pc->capabilities));
strcpy(p->prefix, pc->prefix);
return len;
}
|
