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platform_system_vold/vold_prepare_subdirs.cpp
Jooyung Han 64d727c503 Use /data/misc/apexdata for the list of APEXes 
vold_prepare_subdirs should create apexdata directories for each APEX.
Previously, it gets the list by scanning /apex directory. However,
vold/vold_prepare_subdirs run in the bootstrap mount namespace, they can
see only bootstrap apexes in /apex. The reason why it worked was that
unintended side effects of how we managed /apex directory for both mount
namespace.

Instead, since apexdata directories are already populated by init in
/data/misc/apexdata, we can use that directory for the same purpose.

Bug: 295345486
Test: CtsPackageSettingHostTestCases
Change-Id: I453cd59f54ccbb140f73b5e8576b36fa49f9bc59
2023-08-12 01:05:53 +09:00

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/*
* Copyright (C) 2017 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.
*/
/*
* Tool to create a directory with the right SELinux context applied, or
* apply the context if it's absent. Also fixes mode, uid, gid.
*/
#include <iostream>
#include <string>
#include <vector>
#include <dirent.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <android-base/logging.h>
#include <android-base/scopeguard.h>
#include <cutils/fs.h>
#include <selinux/android.h>
#include "Utils.h"
#include "android/os/IVold.h"
#include <private/android_filesystem_config.h>
static void usage(const char* progname) {
std::cerr << "Usage: " << progname << " [ prepare | destroy ] <volume_uuid> <user_id> <flags>"
<< std::endl;
exit(-1);
}
static bool small_int(const std::string& s) {
return !s.empty() && s.size() < 7 && s.find_first_not_of("0123456789") == std::string::npos;
}
static bool valid_uuid(const std::string& s) {
return s.size() < 40 && s.find_first_not_of("0123456789abcdefABCDEF-_") == std::string::npos;
}
static bool prepare_dir_for_user(struct selabel_handle* sehandle, mode_t mode, uid_t uid, gid_t gid,
const std::string& path, uid_t user_id) {
auto clearfscreatecon = android::base::make_scope_guard([] { setfscreatecon(nullptr); });
auto secontext = std::unique_ptr<char, void (*)(char*)>(nullptr, freecon);
char* tmp_secontext;
if (selabel_lookup(sehandle, &tmp_secontext, path.c_str(), S_IFDIR) == 0) {
secontext.reset(tmp_secontext);
if (user_id != (uid_t)-1) {
if (selinux_android_context_with_level(secontext.get(), &tmp_secontext, user_id,
(uid_t)-1) != 0) {
PLOG(ERROR) << "Unable to create context with level for: " << path;
return false;
}
secontext.reset(tmp_secontext);
}
if (setfscreatecon(secontext.get()) != 0) {
LOG(ERROR) << "Failed to setfscreatecon for directory " << path;
return false;
}
} else if (errno == ENOENT) {
LOG(DEBUG) << "No selabel defined for directory " << path;
} else {
PLOG(ERROR) << "Failed to look up selabel for directory " << path;
return false;
}
LOG(DEBUG) << "Setting up mode " << std::oct << mode << std::dec << " uid " << uid << " gid "
<< gid << " context " << (secontext ? secontext.get() : "null")
<< " on path: " << path;
if (fs_prepare_dir(path.c_str(), mode, uid, gid) != 0) {
return false;
}
if (secontext) {
char* tmp_oldsecontext = nullptr;
if (lgetfilecon(path.c_str(), &tmp_oldsecontext) < 0) {
PLOG(ERROR) << "Unable to read secontext for: " << path;
return false;
}
auto oldsecontext = std::unique_ptr<char, void (*)(char*)>(tmp_oldsecontext, freecon);
if (strcmp(secontext.get(), oldsecontext.get()) != 0) {
LOG(INFO) << "Relabelling from " << ((char*)oldsecontext.get()) << " to "
<< ((char*)secontext.get()) << ": " << path;
if (lsetfilecon(path.c_str(), secontext.get()) != 0) {
PLOG(ERROR) << "Relabelling failed for: " << path;
return false;
}
}
}
return true;
}
static bool prepare_dir(struct selabel_handle* sehandle, mode_t mode, uid_t uid, gid_t gid,
const std::string& path) {
return prepare_dir_for_user(sehandle, mode, uid, gid, path, (uid_t)-1);
}
static bool rmrf_contents(const std::string& path) {
auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir(path.c_str()), closedir);
if (!dirp) {
if (errno == ENOENT) {
return true;
}
PLOG(ERROR) << "Unable to open directory: " << path;
return false;
}
bool res = true;
for (;;) {
errno = 0;
auto const entry = readdir(dirp.get());
if (!entry) {
if (errno) {
PLOG(ERROR) << "readdir failed on: " << path;
return false;
}
return res;
}
if (entry->d_name[0] == '.') continue;
auto subdir = path + "/" + entry->d_name;
if (0 !=
android::vold::ForkExecvp(std::vector<std::string>{"/system/bin/rm", "-rf", subdir})) {
LOG(ERROR) << "rm -rf failed on " << subdir;
res = false;
}
}
}
static bool prepare_apex_subdirs(struct selabel_handle* sehandle, const std::string& path) {
if (!prepare_dir(sehandle, 0711, 0, 0, path + "/apexdata")) return false;
// Since vold/vold_prepare_subdirs run in the bootstrap mount namespace
// we can't get the full list of APEXes by scanning /apex directory.
// Instead, we can look up /data/misc/apexdata for the list of APEXes,
// which is populated during `perform_apex_config` in init.
// Note: `init_user0` should be invoked after `perform_apex_config`.
auto dirp = std::unique_ptr<DIR, int (*)(DIR*)>(opendir("/data/misc/apexdata"), closedir);
if (!dirp) {
PLOG(ERROR) << "Unable to open apex directory";
return false;
}
struct dirent* entry;
while ((entry = readdir(dirp.get())) != nullptr) {
if (entry->d_type != DT_DIR) continue;
const char* name = entry->d_name;
// skip any starting with "."
if (name[0] == '.') continue;
if (!prepare_dir(sehandle, 0771, AID_ROOT, AID_SYSTEM, path + "/apexdata/" + name)) {
return false;
}
}
return true;
}
static bool prepare_subdirs(const std::string& volume_uuid, int user_id, int flags) {
struct selabel_handle* sehandle = selinux_android_file_context_handle();
if (!sehandle) {
LOG(ERROR) << "Failed to get SELinux file contexts handle";
return false;
}
if (flags & android::os::IVold::STORAGE_FLAG_DE) {
auto user_de_path = android::vold::BuildDataUserDePath(volume_uuid, user_id);
if (!prepare_dir_for_user(sehandle, 0771, AID_SYSTEM, AID_SYSTEM, user_de_path, user_id)) {
return false;
}
auto misc_de_path = android::vold::BuildDataMiscDePath(volume_uuid, user_id);
if (!prepare_dir_for_user(sehandle, 0771, AID_SYSTEM, AID_SYSTEM,
misc_de_path + "/sdksandbox", user_id)) {
return false;
}
if (volume_uuid.empty()) {
if (!prepare_dir(sehandle, 0700, 0, 0, misc_de_path + "/vold")) return false;
if (!prepare_dir(sehandle, 0700, 0, 0, misc_de_path + "/storaged")) return false;
if (!prepare_dir(sehandle, 0700, 0, 0, misc_de_path + "/rollback")) return false;
// TODO: Return false if this returns false once sure this should succeed.
prepare_dir(sehandle, 0700, 0, 0, misc_de_path + "/apexrollback");
prepare_apex_subdirs(sehandle, misc_de_path);
auto profiles_de_path = android::vold::BuildDataProfilesDePath(user_id);
if (!prepare_dir_for_user(sehandle, 0771, AID_SYSTEM, AID_SYSTEM, profiles_de_path,
user_id)) {
return false;
}
auto vendor_de_path = android::vold::BuildDataVendorDePath(user_id);
if (!prepare_dir(sehandle, 0700, AID_SYSTEM, AID_SYSTEM, vendor_de_path + "/fpdata")) {
return false;
}
auto facedata_path = vendor_de_path + "/facedata";
if (!prepare_dir(sehandle, 0700, AID_SYSTEM, AID_SYSTEM, facedata_path)) {
return false;
}
}
}
if (flags & android::os::IVold::STORAGE_FLAG_CE) {
auto user_ce_path = android::vold::BuildDataUserCePath(volume_uuid, user_id);
if (!prepare_dir_for_user(sehandle, 0771, AID_SYSTEM, AID_SYSTEM, user_ce_path, user_id)) {
return false;
}
auto misc_ce_path = android::vold::BuildDataMiscCePath(volume_uuid, user_id);
if (!prepare_dir_for_user(sehandle, 0771, AID_SYSTEM, AID_SYSTEM,
misc_ce_path + "/sdksandbox", user_id)) {
return false;
}
if (volume_uuid.empty()) {
if (!prepare_dir(sehandle, 0700, 0, 0, misc_ce_path + "/vold")) return false;
if (!prepare_dir(sehandle, 0700, 0, 0, misc_ce_path + "/storaged")) return false;
if (!prepare_dir(sehandle, 0700, 0, 0, misc_ce_path + "/rollback")) return false;
// TODO: Return false if this returns false once sure this should succeed.
prepare_dir(sehandle, 0700, 0, 0, misc_ce_path + "/apexrollback");
prepare_apex_subdirs(sehandle, misc_ce_path);
// Give gmscore (who runs in cache group) access to the checkin directory. Also provide
// the user id to set the correct selinux mls_level.
if (!prepare_dir_for_user(sehandle, 0770, AID_SYSTEM, AID_CACHE,
misc_ce_path + "/checkin", user_id)) {
// TODO(b/203742483) the checkin directory was created with the wrong permission &
// context. Delete the directory to get these devices out of the bad state. Revert
// the change once the droidfood population is on newer build.
LOG(INFO) << "Failed to prepare the checkin directory, deleting for recreation";
android::vold::DeleteDirContentsAndDir(misc_ce_path + "/checkin");
if (!prepare_dir_for_user(sehandle, 0770, AID_SYSTEM, AID_CACHE,
misc_ce_path + "/checkin", user_id)) {
return false;
}
}
auto system_ce_path = android::vold::BuildDataSystemCePath(user_id);
if (!prepare_dir(sehandle, 0700, AID_SYSTEM, AID_SYSTEM, system_ce_path + "/backup")) {
return false;
}
if (!prepare_dir(sehandle, 0700, AID_SYSTEM, AID_SYSTEM,
system_ce_path + "/backup_stage")) {
return false;
}
auto vendor_ce_path = android::vold::BuildDataVendorCePath(user_id);
auto facedata_path = vendor_ce_path + "/facedata";
if (!prepare_dir(sehandle, 0700, AID_SYSTEM, AID_SYSTEM, facedata_path)) {
return false;
}
}
}
return true;
}
static bool destroy_subdirs(const std::string& volume_uuid, int user_id, int flags) {
bool res = true;
if (flags & android::os::IVold::STORAGE_FLAG_CE) {
auto misc_ce_path = android::vold::BuildDataMiscCePath(volume_uuid, user_id);
res &= rmrf_contents(misc_ce_path);
if (volume_uuid.empty()) {
auto vendor_ce_path = android::vold::BuildDataVendorCePath(user_id);
res &= rmrf_contents(vendor_ce_path);
}
}
if (flags & android::os::IVold::STORAGE_FLAG_DE) {
auto misc_de_path = android::vold::BuildDataMiscDePath(volume_uuid, user_id);
res &= rmrf_contents(misc_de_path);
if (volume_uuid.empty()) {
auto vendor_de_path = android::vold::BuildDataVendorDePath(user_id);
res &= rmrf_contents(vendor_de_path);
}
}
return res;
}
int main(int argc, const char* const argv[]) {
android::base::InitLogging(const_cast<char**>(argv));
std::vector<std::string> args(argv + 1, argv + argc);
if (args.size() != 4 || !valid_uuid(args[1]) || !small_int(args[2]) || !small_int(args[3])) {
usage(argv[0]);
return -1;
}
auto volume_uuid = args[1];
int user_id = stoi(args[2]);
int flags = stoi(args[3]);
if (args[0] == "prepare") {
if (!prepare_subdirs(volume_uuid, user_id, flags)) return -1;
} else if (args[0] == "destroy") {
if (!destroy_subdirs(volume_uuid, user_id, flags)) return -1;
} else {
usage(argv[0]);
return -1;
}
return 0;
}
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