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/*
* 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.
*/
#include <private/fs_config.h>
// 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"
#include <errno.h>
#include <fcntl.h>
#include <fnmatch.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <string>
#include <android-base/strings.h>
#include <cutils/fs.h>
#include <log/log.h>
#include <private/android_filesystem_config.h>
#include "fs_config.h"
using android::base::EndsWith;
using android::base::StartsWith;
#define ALIGN(x, alignment) (((x) + ((alignment)-1)) & ~((alignment)-1))
#define CAP_MASK_LONG(cap_name) (1ULL << (cap_name))
// 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[] = {
// clang-format off
{ 00770, AID_SYSTEM, AID_CACHE, 0, "cache" },
{ 00555, AID_ROOT, AID_ROOT, 0, "config" },
{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app" },
{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private" },
{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data/app-ephemeral" },
{ 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" },
{ 00770, AID_DHCP, AID_DHCP, 0, "data/misc/dhcp" },
{ 00771, AID_SHARED_RELRO, AID_SHARED_RELRO, 0, "data/misc/shared_relro" },
{ 01771, AID_SYSTEM, AID_MISC, 0, "data/misc" },
{ 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/Music" },
{ 00775, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media" },
{ 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest" },
{ 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest64" },
{ 00750, AID_ROOT, AID_SHELL, 0, "data/benchmarktest" },
{ 00750, AID_ROOT, AID_SHELL, 0, "data/benchmarktest64" },
{ 00775, AID_ROOT, AID_ROOT, 0, "data/preloads" },
{ 00771, AID_SYSTEM, AID_SYSTEM, 0, "data" },
{ 00755, AID_ROOT, AID_SYSTEM, 0, "mnt" },
{ 00751, AID_ROOT, AID_SHELL, 0, "product/bin" },
{ 00751, AID_ROOT, AID_SHELL, 0, "product/apex/*/bin" },
{ 00777, AID_ROOT, AID_ROOT, 0, "sdcard" },
{ 00751, AID_ROOT, AID_SDCARD_R, 0, "storage" },
{ 00750, AID_ROOT, AID_SYSTEM, 0, "system/apex/com.android.tethering/bin/for-system" },
{ 00751, AID_ROOT, AID_SHELL, 0, "system/bin" },
{ 00755, AID_ROOT, AID_ROOT, 0, "system/etc/ppp" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/vendor" },
{ 00750, AID_ROOT, AID_SHELL, 0, "system/xbin" },
{ 00751, AID_ROOT, AID_SHELL, 0, "system/apex/*/bin" },
{ 00750, AID_ROOT, AID_SYSTEM, 0, "system_ext/apex/com.android.tethering/bin/for-system" },
{ 00751, AID_ROOT, AID_SHELL, 0, "system_ext/bin" },
{ 00751, AID_ROOT, AID_SHELL, 0, "system_ext/apex/*/bin" },
{ 00751, AID_ROOT, AID_SHELL, 0, "vendor/bin" },
{ 00751, AID_ROOT, AID_SHELL, 0, "vendor/apex/*/bin" },
{ 00755, AID_ROOT, AID_SHELL, 0, "vendor" },
{ 00755, AID_ROOT, AID_ROOT, 0, 0 },
// clang-format on
};
#ifndef __ANDROID_VNDK__
auto __for_testing_only__android_dirs = android_dirs;
#endif
// 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 sys_conf_dir[] = "/system/etc/fs_config_dirs";
static const char sys_conf_file[] = "/system/etc/fs_config_files";
// No restrictions are placed on the vendor and oem file-system config files,
// although the developer is advised to restrict the scope to the /vendor or
// oem/ file-system since the intent is to provide support for customized
// portions of a separate vendor.img or oem.img. Has to remain open so that
// customization can also land on /system/vendor, /system/oem, /system/odm,
// /system/product or /system/system_ext.
//
// We expect build-time checking or filtering when constructing the associated
// fs_config_* files (see build/tools/fs_config/fs_config_generate.c)
static const char ven_conf_dir[] = "/vendor/etc/fs_config_dirs";
static const char ven_conf_file[] = "/vendor/etc/fs_config_files";
static const char oem_conf_dir[] = "/oem/etc/fs_config_dirs";
static const char oem_conf_file[] = "/oem/etc/fs_config_files";
static const char odm_conf_dir[] = "/odm/etc/fs_config_dirs";
static const char odm_conf_file[] = "/odm/etc/fs_config_files";
static const char product_conf_dir[] = "/product/etc/fs_config_dirs";
static const char product_conf_file[] = "/product/etc/fs_config_files";
static const char system_ext_conf_dir[] = "/system_ext/etc/fs_config_dirs";
static const char system_ext_conf_file[] = "/system_ext/etc/fs_config_files";
static const char* conf[][2] = {
{sys_conf_file, sys_conf_dir}, {ven_conf_file, ven_conf_dir},
{oem_conf_file, oem_conf_dir}, {odm_conf_file, odm_conf_dir},
{product_conf_file, product_conf_dir}, {system_ext_conf_file, system_ext_conf_dir},
};
// Do not use android_files to grant Linux capabilities. Use ambient capabilities in their
// associated init.rc file instead. See https://source.android.com/devices/tech/config/ambient.
// Do not place any new vendor/, data/vendor/, etc entries in android_files.
// Vendor entries should be done via a vendor or device specific config.fs.
// See https://source.android.com/devices/tech/config/filesystem#using-file-system-capabilities
static const struct fs_path_config android_files[] = {
// clang-format off
{ 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app/*" },
{ 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app-ephemeral/*" },
{ 00644, AID_SYSTEM, AID_SYSTEM, 0, "data/app-private/*" },
{ 00644, AID_APP, AID_APP, 0, "data/data/*" },
{ 00644, AID_MEDIA_RW, AID_MEDIA_RW, 0, "data/media/*" },
{ 00640, AID_ROOT, AID_SHELL, 0, "data/nativetest/tests.txt" },
{ 00640, AID_ROOT, AID_SHELL, 0, "data/nativetest64/tests.txt" },
{ 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest/*" },
{ 00750, AID_ROOT, AID_SHELL, 0, "data/nativetest64/*" },
{ 00750, AID_ROOT, AID_SHELL, 0, "data/benchmarktest/*" },
{ 00750, AID_ROOT, AID_SHELL, 0, "data/benchmarktest64/*" },
{ 00600, AID_ROOT, AID_ROOT, 0, "default.prop" }, // legacy
{ 00600, AID_ROOT, AID_ROOT, 0, "system/etc/prop.default" },
{ 00600, AID_ROOT, AID_ROOT, 0, "odm/build.prop" }, // legacy; only for P release
{ 00600, AID_ROOT, AID_ROOT, 0, "odm/default.prop" }, // legacy; only for P release
{ 00600, AID_ROOT, AID_ROOT, 0, "odm/etc/build.prop" },
{ 00444, AID_ROOT, AID_ROOT, 0, odm_conf_dir + 1 },
{ 00444, AID_ROOT, AID_ROOT, 0, odm_conf_file + 1 },
{ 00444, AID_ROOT, AID_ROOT, 0, oem_conf_dir + 1 },
{ 00444, AID_ROOT, AID_ROOT, 0, oem_conf_file + 1 },
{ 00600, AID_ROOT, AID_ROOT, 0, "product/build.prop" },
{ 00444, AID_ROOT, AID_ROOT, 0, product_conf_dir + 1 },
{ 00444, AID_ROOT, AID_ROOT, 0, product_conf_file + 1 },
{ 00600, AID_ROOT, AID_ROOT, 0, "system_ext/build.prop" },
{ 00444, AID_ROOT, AID_ROOT, 0, system_ext_conf_dir + 1 },
{ 00444, AID_ROOT, AID_ROOT, 0, system_ext_conf_file + 1 },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/bin/crash_dump32" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/bin/crash_dump64" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/bin/debuggerd" },
{ 00550, AID_LOGD, AID_LOGD, 0, "system/bin/logd" },
{ 00700, AID_ROOT, AID_ROOT, 0, "system/bin/secilc" },
{ 00750, AID_ROOT, AID_ROOT, 0, "system/bin/uncrypt" },
{ 00600, AID_ROOT, AID_ROOT, 0, "system/build.prop" },
{ 00444, AID_ROOT, AID_ROOT, 0, sys_conf_dir + 1 },
{ 00444, AID_ROOT, AID_ROOT, 0, sys_conf_file + 1 },
{ 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" },
{ 00555, AID_ROOT, AID_ROOT, 0, "system/etc/ppp/*" },
{ 00555, AID_ROOT, AID_ROOT, 0, "system/etc/rc.*" },
{ 00750, AID_ROOT, AID_ROOT, 0, "vendor/bin/install-recovery.sh" },
{ 00600, AID_ROOT, AID_ROOT, 0, "vendor/build.prop" },
{ 00600, AID_ROOT, AID_ROOT, 0, "vendor/default.prop" },
{ 00440, AID_ROOT, AID_ROOT, 0, "vendor/etc/recovery.img" },
{ 00444, AID_ROOT, AID_ROOT, 0, ven_conf_dir + 1 },
{ 00444, AID_ROOT, AID_ROOT, 0, ven_conf_file + 1 },
// the following two files are INTENTIONALLY set-uid, but they
// are NOT included on user builds.
{ 06755, AID_ROOT, AID_ROOT, 0, "system/xbin/procmem" },
{ 04750, AID_ROOT, AID_SHELL, 0, "system/xbin/su" },
// the following files have enhanced capabilities and ARE included
// in user builds.
{ 06755, AID_CLAT, AID_CLAT, 0, "system/apex/com.android.tethering/bin/for-system/clatd" },
{ 06755, AID_CLAT, AID_CLAT, 0, "system_ext/apex/com.android.tethering/bin/for-system/clatd" },
{ 00700, AID_SYSTEM, AID_SHELL, CAP_MASK_LONG(CAP_BLOCK_SUSPEND),
"system/bin/inputflinger" },
{ 00750, AID_ROOT, AID_SHELL, CAP_MASK_LONG(CAP_SETUID) |
CAP_MASK_LONG(CAP_SETGID),
"system/bin/run-as" },
{ 00750, AID_ROOT, AID_SHELL, CAP_MASK_LONG(CAP_SETUID) |
CAP_MASK_LONG(CAP_SETGID),
"system/bin/simpleperf_app_runner" },
{ 00755, AID_ROOT, AID_ROOT, 0, "first_stage_ramdisk/system/bin/e2fsck" },
#ifdef __LP64__
{ 00755, AID_ROOT, AID_ROOT, 0, "first_stage_ramdisk/system/bin/linker64" },
#else
{ 00755, AID_ROOT, AID_ROOT, 0, "first_stage_ramdisk/system/bin/linker" },
#endif
{ 00755, AID_ROOT, AID_ROOT, 0, "first_stage_ramdisk/system/bin/resize2fs" },
{ 00755, AID_ROOT, AID_ROOT, 0, "first_stage_ramdisk/system/bin/snapuserd" },
{ 00755, AID_ROOT, AID_ROOT, 0, "first_stage_ramdisk/system/bin/snapuserd_ramdisk" },
{ 00755, AID_ROOT, AID_ROOT, 0, "first_stage_ramdisk/system/bin/tune2fs" },
{ 00755, AID_ROOT, AID_ROOT, 0, "first_stage_ramdisk/system/bin/fsck.f2fs" },
// generic defaults
{ 00755, AID_ROOT, AID_ROOT, 0, "bin/*" },
{ 00640, AID_ROOT, AID_SHELL, 0, "fstab.*" },
{ 00750, AID_ROOT, AID_SHELL, 0, "init*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "odm/bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "product/bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "product/apex/*bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/xbin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system/apex/*/bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system_ext/bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "system_ext/apex/*/bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "vendor/bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "vendor/apex/*bin/*" },
{ 00755, AID_ROOT, AID_SHELL, 0, "vendor/xbin/*" },
{ 00644, AID_ROOT, AID_ROOT, 0, 0 },
// clang-format on
};
#ifndef __ANDROID_VNDK__
auto __for_testing_only__android_files = android_files;
#endif
static size_t strip(const char* path, size_t len, const char suffix[]) {
if (len < strlen(suffix)) return len;
if (strncmp(path + len - strlen(suffix), suffix, strlen(suffix))) return len;
return len - strlen(suffix);
}
static int fs_config_open(int dir, int which, const char* target_out_path) {
int fd = -1;
if (target_out_path && *target_out_path) {
// target_out_path is the path to the directory holding content of
// system partition but as we cannot guarantee it ends with '/system'
// or with or without a trailing slash, need to strip them carefully.
char* name = NULL;
size_t len = strlen(target_out_path);
len = strip(target_out_path, len, "/");
len = strip(target_out_path, len, "/system");
if (asprintf(&name, "%.*s%s", (int)len, target_out_path, conf[which][dir]) != -1) {
fd = TEMP_FAILURE_RETRY(open(name, O_RDONLY));
free(name);
}
}
if (fd < 0) {
fd = TEMP_FAILURE_RETRY(open(conf[which][dir], O_RDONLY));
}
return fd;
}
// if path is "odm/<stuff>", "oem/<stuff>", "product/<stuff>",
// "system_ext/<stuff>" or "vendor/<stuff>"
static bool is_partition(const std::string& path) {
static const char* partitions[] = {"odm/", "oem/", "product/", "system_ext/", "vendor/"};
for (size_t i = 0; i < (sizeof(partitions) / sizeof(partitions[0])); ++i) {
if (StartsWith(path, partitions[i])) return true;
}
return false;
}
// alias prefixes of "<partition>/<stuff>" to "system/<partition>/<stuff>" or
// "system/<partition>/<stuff>" to "<partition>/<stuff>"
static bool fs_config_cmp(bool dir, const char* prefix, size_t len, const char* path, size_t plen) {
std::string pattern(prefix, len);
std::string input(path, plen);
// Massage pattern and input so that they can be used by fnmatch where
// directories have to end with /.
if (dir) {
if (!EndsWith(input, "/")) {
input.append("/");
}
if (!EndsWith(pattern, "/*")) {
if (EndsWith(pattern, "/")) {
pattern.append("*");
} else {
pattern.append("/*");
}
}
}
// no FNM_PATHNAME is set in order to match a/b/c/d with a/*
// FNM_ESCAPE is set in order to prevent using \\? and \\* and maintenance issues.
const int fnm_flags = FNM_NOESCAPE;
if (fnmatch(pattern.c_str(), input.c_str(), fnm_flags) == 0) return true;
// Check match between logical partition's files and patterns.
static constexpr const char* kLogicalPartitions[] = {"system/product/", "system/system_ext/",
"system/vendor/", "vendor/odm/"};
for (auto& logical_partition : kLogicalPartitions) {
if (StartsWith(input, logical_partition)) {
std::string input_in_partition = input.substr(input.find('/') + 1);
if (!is_partition(input_in_partition)) continue;
if (fnmatch(pattern.c_str(), input_in_partition.c_str(), fnm_flags) == 0) {
return true;
}
}
}
return false;
}
#ifndef __ANDROID_VNDK__
auto __for_testing_only__fs_config_cmp = fs_config_cmp;
#endif
void fs_config(const char* path, int dir, const char* target_out_path, unsigned* uid, unsigned* gid,
unsigned* mode, uint64_t* capabilities) {
const struct fs_path_config* pc;
size_t which, plen;
if (path[0] == '/') {
path++;
}
plen = strlen(path);
for (which = 0; which < (sizeof(conf) / sizeof(conf[0])); ++which) {
struct fs_path_config_from_file header;
int fd = fs_config_open(dir, which, target_out_path);
if (fd < 0) continue;
while (TEMP_FAILURE_RETRY(read(fd, &header, sizeof(header))) == sizeof(header)) {
char* prefix;
uint16_t host_len = header.len;
ssize_t len, remainder = host_len - sizeof(header);
if (remainder <= 0) {
ALOGE("%s len is corrupted", conf[which][dir]);
break;
}
prefix = static_cast<char*>(calloc(1, remainder));
if (!prefix) {
ALOGE("%s out of memory", conf[which][dir]);
break;
}
if (TEMP_FAILURE_RETRY(read(fd, prefix, remainder)) != remainder) {
free(prefix);
ALOGE("%s prefix is truncated", conf[which][dir]);
break;
}
len = strnlen(prefix, remainder);
if (len >= remainder) { // missing a terminating null
free(prefix);
ALOGE("%s is corrupted", conf[which][dir]);
break;
}
if (fs_config_cmp(dir, prefix, len, path, plen)) {
free(prefix);
close(fd);
*uid = header.uid;
*gid = header.gid;
*mode = (*mode & (~07777)) | header.mode;
*capabilities = header.capabilities;
return;
}
free(prefix);
}
close(fd);
}
for (pc = dir ? android_dirs : android_files; 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;
}
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