1 /*
2 * Copyright (C) 2007 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 #define LOG_TAG "fs_config"
23
24 #define _GNU_SOURCE
25
26 #include <errno.h>
27 #include <fcntl.h>
28 #include <stdbool.h>
29 #include <stdint.h>
30 #include <stdio.h>
31 #include <stdlib.h>
32 #include <string.h>
33 #include <sys/stat.h>
34 #include <sys/types.h>
35
36 #include <log/log.h>
37 #include <private/android_filesystem_config.h>
38 #include <private/fs_config.h>
39 #include <utils/Compat.h>
40
41 #ifndef O_BINARY
42 #define O_BINARY 0
43 #endif
44
45 /* My kingdom for <endian.h> */
get2LE(const uint8_t * src)46 static inline uint16_t get2LE(const uint8_t* src) { return src[0] | (src[1] << 8); }
47
get8LE(const uint8_t * src)48 static inline uint64_t get8LE(const uint8_t* src) {
49 uint32_t low, high;
50
51 low = src[0] | (src[1] << 8) | (src[2] << 16) | (src[3] << 24);
52 high = src[4] | (src[5] << 8) | (src[6] << 16) | (src[7] << 24);
53 return ((uint64_t)high << 32) | (uint64_t)low;
54 }
55
56 #define ALIGN(x, alignment) (((x) + ((alignment)-1)) & ~((alignment)-1))
57
58 /* Rules for directories.
59 ** These rules are applied based on "first match", so they
60 ** should start with the most specific path and work their
61 ** way up to the root.
62 */
63
64 static const struct fs_path_config android_dirs[] = {
65 /* clang-format off */
66 { 00770, AID_SYSTEM, AID_CACHE, 0, "cache" },
67 { 00500, AID_ROOT, AID_ROOT, 0, "config" },
68 { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app" },
69 { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private" },
70 { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-ephemeral" },
71 { 00771, AID_ROOT, AID_ROOT, 0, "data/dalvik-cache" },
72 { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/data" },
73 { 00771, AID_SHELL, AID_SHELL, 0, "data/local/tmp" },
74 { 00771, AID_SHELL, AID_SHELL, 0, "data/local" },
75 { 00770, AID_DHCP, AID_DHCP, 0, "data/misc/dhcp" },
76 { 00771, AID_SHARED_RELRO, AID_SHARED_RELRO, 0, "data/misc/shared_relro" },
77 { 01771, AID_SYSTEM, AID_MISC, 0, "data/misc" },
78 { 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/Music" },
79 { 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media" },
80 { 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest" },
81 { 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest64" },
82 { 00775, AID_ROOT, AID_ROOT, 0, "data/preloads" },
83 { 00771, AID_SYSTEM, AID_SYSTEM, 0, "data" },
84 { 00755, AID_ROOT, AID_SYSTEM, 0, "mnt" },
85 { 00755, AID_ROOT, AID_ROOT, 0, "root" },
86 { 00750, AID_ROOT, AID_SHELL, 0, "sbin" },
87 { 00777, AID_ROOT, AID_ROOT, 0, "sdcard" },
88 { 00751, AID_ROOT, AID_SDCARD_R, 0, "storage" },
89 { 00755, AID_ROOT, AID_SHELL, 0, "system/bin" },
90 { 00755, AID_ROOT, AID_ROOT, 0, "system/etc/ppp" },
91 { 00755, AID_ROOT, AID_SHELL, 0, "system/vendor" },
92 { 00755, AID_ROOT, AID_SHELL, 0, "system/xbin" },
93 { 00755, AID_ROOT, AID_SHELL, 0, "vendor" },
94 { 00755, AID_ROOT, AID_ROOT, 0, 0 },
95 /* clang-format on */
96 };
97
98 /* Rules for files.
99 ** These rules are applied based on "first match", so they
100 ** should start with the most specific path and work their
101 ** way up to the root. Prefixes ending in * denotes wildcard
102 ** and will allow partial matches.
103 */
104 static const char sys_conf_dir[] = "/system/etc/fs_config_dirs";
105 static const char sys_conf_file[] = "/system/etc/fs_config_files";
106 /* No restrictions are placed on the vendor and oem file-system config files,
107 * although the developer is advised to restrict the scope to the /vendor or
108 * oem/ file-system since the intent is to provide support for customized
109 * portions of a separate vendor.img or oem.img. Has to remain open so that
110 * customization can also land on /system/vendor, /system/oem or /system/odm.
111 * We expect build-time checking or filtering when constructing the associated
112 * fs_config_* files (see build/tools/fs_config/fs_config_generate.c)
113 */
114 static const char ven_conf_dir[] = "/vendor/etc/fs_config_dirs";
115 static const char ven_conf_file[] = "/vendor/etc/fs_config_files";
116 static const char oem_conf_dir[] = "/oem/etc/fs_config_dirs";
117 static const char oem_conf_file[] = "/oem/etc/fs_config_files";
118 static const char odm_conf_dir[] = "/odm/etc/fs_config_dirs";
119 static const char odm_conf_file[] = "/odm/etc/fs_config_files";
120 static const char* conf[][2] = {
121 {sys_conf_file, sys_conf_dir},
122 {ven_conf_file, ven_conf_dir},
123 {oem_conf_file, oem_conf_dir},
124 {odm_conf_file, odm_conf_dir},
125 };
126
127 static const struct fs_path_config android_files[] = {
128 /* clang-format off */
129 { 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app/*" },
130 { 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app-ephemeral/*" },
131 { 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private/*" },
132 { 00644, AID_APP, AID_APP, 0, "data/data/*" },
133 { 00644, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/*" },
134 { 00640, AID_ROOT, AID_SHELL, 0, "data/nativetest/tests.txt" },
135 { 00640, AID_ROOT, AID_SHELL, 0, "data/nativetest64/tests.txt" },
136 { 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest/*" },
137 { 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest64/*" },
138 { 00600, AID_ROOT, AID_ROOT, 0, "default.prop" }, // legacy
139 { 00600, AID_ROOT, AID_ROOT, 0, "system/etc/prop.default" },
140 { 00600, AID_ROOT, AID_ROOT, 0, "odm/build.prop" },
141 { 00600, AID_ROOT, AID_ROOT, 0, "odm/default.prop" },
142 { 00444, AID_ROOT, AID_ROOT, 0, odm_conf_dir + 1 },
143 { 00444, AID_ROOT, AID_ROOT, 0, odm_conf_file + 1 },
144 { 00600, AID_ROOT, AID_ROOT, 0, "system/odm/build.prop" },
145 { 00600, AID_ROOT, AID_ROOT, 0, "system/odm/default.prop" },
146 { 00444, AID_ROOT, AID_ROOT, 0, "system/odm/etc/fs_config_dirs" },
147 { 00444, AID_ROOT, AID_ROOT, 0, "system/odm/etc/fs_config_files" },
148 { 00444, AID_ROOT, AID_ROOT, 0, oem_conf_dir + 1 },
149 { 00444, AID_ROOT, AID_ROOT, 0, oem_conf_file + 1 },
150 { 00444, AID_ROOT, AID_ROOT, 0, "system/oem/etc/fs_config_dirs" },
151 { 00444, AID_ROOT, AID_ROOT, 0, "system/oem/etc/fs_config_files" },
152 { 00750, AID_ROOT, AID_SHELL, 0, "sbin/fs_mgr" },
153 { 00755, AID_ROOT, AID_SHELL, 0, "system/bin/crash_dump32" },
154 { 00755, AID_ROOT, AID_SHELL, 0, "system/bin/crash_dump64" },
155 { 00755, AID_ROOT, AID_SHELL, 0, "system/bin/debuggerd" },
156 { 00750, AID_ROOT, AID_ROOT, 0, "system/bin/install-recovery.sh" },
157 { 00700, AID_ROOT, AID_ROOT, 0, "system/bin/secilc" },
158 { 00750, AID_ROOT, AID_ROOT, 0, "system/bin/uncrypt" },
159 { 00600, AID_ROOT, AID_ROOT, 0, "system/build.prop" },
160 { 00444, AID_ROOT, AID_ROOT, 0, sys_conf_dir + 1 },
161 { 00444, AID_ROOT, AID_ROOT, 0, sys_conf_file + 1 },
162 { 00440, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.rc" },
163 { 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.goldfish.sh" },
164 { 00550, AID_ROOT, AID_SHELL, 0, "system/etc/init.ril" },
165 { 00555, AID_ROOT, AID_ROOT, 0, "system/etc/ppp/*" },
166 { 00555, AID_ROOT, AID_ROOT, 0, "system/etc/rc.*" },
167 { 00440, AID_ROOT, AID_ROOT, 0, "system/etc/recovery.img" },
168 { 00600, AID_ROOT, AID_ROOT, 0, "system/vendor/build.prop" },
169 { 00600, AID_ROOT, AID_ROOT, 0, "system/vendor/default.prop" },
170 { 00444, AID_ROOT, AID_ROOT, 0, "system/vendor/etc/fs_config_dirs" },
171 { 00444, AID_ROOT, AID_ROOT, 0, "system/vendor/etc/fs_config_files" },
172 { 00600, AID_ROOT, AID_ROOT, 0, "vendor/build.prop" },
173 { 00600, AID_ROOT, AID_ROOT, 0, "vendor/default.prop" },
174 { 00444, AID_ROOT, AID_ROOT, 0, ven_conf_dir + 1 },
175 { 00444, AID_ROOT, AID_ROOT, 0, ven_conf_file + 1 },
176
177 /* the following two files are INTENTIONALLY set-uid, but they
178 * are NOT included on user builds. */
179 { 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/procmem" },
180 { 04750, AID_ROOT, AID_SHELL, 0, "system/xbin/su" },
181
182 /* the following files have enhanced capabilities and ARE included
183 * in user builds. */
184 { 00700, AID_SYSTEM, AID_SHELL, CAP_MASK_LONG(CAP_BLOCK_SUSPEND),
185 "system/bin/inputflinger" },
186 { 00550, AID_LOGD, AID_LOGD, CAP_MASK_LONG(CAP_SYSLOG) |
187 CAP_MASK_LONG(CAP_AUDIT_CONTROL) |
188 CAP_MASK_LONG(CAP_SETGID),
189 "system/bin/logd" },
190 { 00750, AID_ROOT, AID_SHELL, CAP_MASK_LONG(CAP_SETUID) |
191 CAP_MASK_LONG(CAP_SETGID),
192 "system/bin/run-as" },
193
194 /* Support FIFO scheduling mode in SurfaceFlinger. */
195 { 00755, AID_SYSTEM, AID_GRAPHICS, CAP_MASK_LONG(CAP_SYS_NICE),
196 "system/bin/surfaceflinger" },
197
198 /* Support hostapd administering a network interface. */
199 { 00755, AID_WIFI, AID_WIFI, CAP_MASK_LONG(CAP_NET_ADMIN) |
200 CAP_MASK_LONG(CAP_NET_RAW),
201 "system/vendor/bin/hostapd" },
202 { 00755, AID_WIFI, AID_WIFI, CAP_MASK_LONG(CAP_NET_ADMIN) |
203 CAP_MASK_LONG(CAP_NET_RAW),
204 "vendor/bin/hostapd" },
205
206 /* Support Bluetooth legacy hal accessing /sys/class/rfkill
207 * Support RT scheduling in Bluetooth */
208 { 00700, AID_BLUETOOTH, AID_BLUETOOTH, CAP_MASK_LONG(CAP_NET_ADMIN) |
209 CAP_MASK_LONG(CAP_SYS_NICE),
210 "system/vendor/bin/hw/android.hardware.bluetooth@1.0-service" },
211 { 00700, AID_BLUETOOTH, AID_BLUETOOTH, CAP_MASK_LONG(CAP_NET_ADMIN) |
212 CAP_MASK_LONG(CAP_SYS_NICE),
213 "vendor/bin/hw/android.hardware.bluetooth@1.0-service" },
214
215 /* Support wifi_hal_legacy administering a network interface. */
216 { 00755, AID_WIFI, AID_WIFI, CAP_MASK_LONG(CAP_NET_ADMIN) |
217 CAP_MASK_LONG(CAP_NET_RAW),
218 "system/vendor/bin/hw/android.hardware.wifi@1.0-service" },
219 { 00755, AID_WIFI, AID_WIFI, CAP_MASK_LONG(CAP_NET_ADMIN) |
220 CAP_MASK_LONG(CAP_NET_RAW),
221 "vendor/bin/hw/android.hardware.wifi@1.0-service" },
222
223 /* A non-privileged zygote that spawns
224 * isolated processes for web rendering. */
225 { 0750, AID_ROOT, AID_ROOT, CAP_MASK_LONG(CAP_SETUID) |
226 CAP_MASK_LONG(CAP_SETGID) |
227 CAP_MASK_LONG(CAP_SETPCAP),
228 "system/bin/webview_zygote32" },
229 { 0750, AID_ROOT, AID_ROOT, CAP_MASK_LONG(CAP_SETUID) |
230 CAP_MASK_LONG(CAP_SETGID) |
231 CAP_MASK_LONG(CAP_SETPCAP),
232 "system/bin/webview_zygote64" },
233
234 /* generic defaults */
235 { 00755, AID_ROOT, AID_ROOT, 0, "bin/*" },
236 { 00640, AID_ROOT, AID_SHELL, 0, "fstab.*" },
237 { 00750, AID_ROOT, AID_SHELL, 0, "init*" },
238 { 00750, AID_ROOT, AID_SHELL, 0, "sbin/*" },
239 { 00755, AID_ROOT, AID_SHELL, 0, "system/bin/*" },
240 { 00755, AID_ROOT, AID_ROOT, 0, "system/lib/valgrind/*" },
241 { 00755, AID_ROOT, AID_ROOT, 0, "system/lib64/valgrind/*" },
242 { 00755, AID_ROOT, AID_SHELL, 0, "system/vendor/bin/*" },
243 { 00755, AID_ROOT, AID_SHELL, 0, "system/vendor/xbin/*" },
244 { 00755, AID_ROOT, AID_SHELL, 0, "system/xbin/*" },
245 { 00755, AID_ROOT, AID_SHELL, 0, "vendor/bin/*" },
246 { 00755, AID_ROOT, AID_SHELL, 0, "vendor/xbin/*" },
247 { 00644, AID_ROOT, AID_ROOT, 0, 0 },
248 /* clang-format on */
249 };
250
strip(const char * path,size_t len,const char suffix[])251 static size_t strip(const char* path, size_t len, const char suffix[]) {
252 if (len < strlen(suffix)) return len;
253 if (strncmp(path + len - strlen(suffix), suffix, strlen(suffix))) return len;
254 return len - strlen(suffix);
255 }
256
fs_config_open(int dir,int which,const char * target_out_path)257 static int fs_config_open(int dir, int which, const char* target_out_path) {
258 int fd = -1;
259
260 if (target_out_path && *target_out_path) {
261 /* target_out_path is the path to the directory holding content of
262 * system partition but as we cannot guarantee it ends with '/system'
263 * or with or without a trailing slash, need to strip them carefully. */
264 char* name = NULL;
265 size_t len = strlen(target_out_path);
266 len = strip(target_out_path, len, "/");
267 len = strip(target_out_path, len, "/system");
268 if (asprintf(&name, "%.*s%s", (int)len, target_out_path, conf[which][dir]) != -1) {
269 fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY | O_BINARY));
270 free(name);
271 }
272 }
273 if (fd < 0) {
274 fd = TEMP_FAILURE_RETRY(open(conf[which][dir], O_RDONLY | O_BINARY));
275 }
276 return fd;
277 }
278
fs_config_cmp(bool dir,const char * prefix,size_t len,const char * path,size_t plen)279 static bool fs_config_cmp(bool dir, const char* prefix, size_t len, const char* path, size_t plen) {
280 if (dir) {
281 if (plen < len) {
282 return false;
283 }
284 } else {
285 /* If name ends in * then allow partial matches. */
286 if (prefix[len - 1] == '*') {
287 return !strncmp(prefix, path, len - 1);
288 }
289 if (plen != len) {
290 return false;
291 }
292 }
293 return !strncmp(prefix, path, len);
294 }
295
fs_config(const char * path,int dir,const char * target_out_path,unsigned * uid,unsigned * gid,unsigned * mode,uint64_t * capabilities)296 void fs_config(const char* path, int dir, const char* target_out_path, unsigned* uid, unsigned* gid,
297 unsigned* mode, uint64_t* capabilities) {
298 const struct fs_path_config* pc;
299 size_t which, plen;
300
301 if (path[0] == '/') {
302 path++;
303 }
304
305 plen = strlen(path);
306
307 for (which = 0; which < (sizeof(conf) / sizeof(conf[0])); ++which) {
308 struct fs_path_config_from_file header;
309
310 int fd = fs_config_open(dir, which, target_out_path);
311 if (fd < 0) continue;
312
313 while (TEMP_FAILURE_RETRY(read(fd, &header, sizeof(header))) == sizeof(header)) {
314 char* prefix;
315 uint16_t host_len = get2LE((const uint8_t*)&header.len);
316 ssize_t len, remainder = host_len - sizeof(header);
317 if (remainder <= 0) {
318 ALOGE("%s len is corrupted", conf[which][dir]);
319 break;
320 }
321 prefix = calloc(1, remainder);
322 if (!prefix) {
323 ALOGE("%s out of memory", conf[which][dir]);
324 break;
325 }
326 if (TEMP_FAILURE_RETRY(read(fd, prefix, remainder)) != remainder) {
327 free(prefix);
328 ALOGE("%s prefix is truncated", conf[which][dir]);
329 break;
330 }
331 len = strnlen(prefix, remainder);
332 if (len >= remainder) { /* missing a terminating null */
333 free(prefix);
334 ALOGE("%s is corrupted", conf[which][dir]);
335 break;
336 }
337 if (fs_config_cmp(dir, prefix, len, path, plen)) {
338 free(prefix);
339 close(fd);
340 *uid = get2LE((const uint8_t*)&(header.uid));
341 *gid = get2LE((const uint8_t*)&(header.gid));
342 *mode = (*mode & (~07777)) | get2LE((const uint8_t*)&(header.mode));
343 *capabilities = get8LE((const uint8_t*)&(header.capabilities));
344 return;
345 }
346 free(prefix);
347 }
348 close(fd);
349 }
350
351 for (pc = dir ? android_dirs : android_files; pc->prefix; pc++) {
352 if (fs_config_cmp(dir, pc->prefix, strlen(pc->prefix), path, plen)) {
353 break;
354 }
355 }
356 *uid = pc->uid;
357 *gid = pc->gid;
358 *mode = (*mode & (~07777)) | pc->mode;
359 *capabilities = pc->capabilities;
360 }
361
fs_config_generate(char * buffer,size_t length,const struct fs_path_config * pc)362 ssize_t fs_config_generate(char* buffer, size_t length, const struct fs_path_config* pc) {
363 struct fs_path_config_from_file* p = (struct fs_path_config_from_file*)buffer;
364 size_t len = ALIGN(sizeof(*p) + strlen(pc->prefix) + 1, sizeof(uint64_t));
365
366 if ((length < len) || (len > UINT16_MAX)) {
367 return -ENOSPC;
368 }
369 memset(p, 0, len);
370 uint16_t host_len = len;
371 p->len = get2LE((const uint8_t*)&host_len);
372 p->mode = get2LE((const uint8_t*)&(pc->mode));
373 p->uid = get2LE((const uint8_t*)&(pc->uid));
374 p->gid = get2LE((const uint8_t*)&(pc->gid));
375 p->capabilities = get8LE((const uint8_t*)&(pc->capabilities));
376 strcpy(p->prefix, pc->prefix);
377 return len;
378 }
379