platform_system_core/init/util.h
Eric Biggers 6cb5a36f4c init: fix mkdir to reliably detect top-level /data directories
To determine the default encryption action, the mkdir command checks
whether the given path is a top-level directory of /data.  However, it
assumed a path without any duplicate slashes or trailing slash(es).

While everyone *should* be providing paths without unnecessary slashes,
it is not guaranteed, as paths with unnecessary slashes still work
correctly for all other parts of the mkdir command, including the
SELinux label lookup and the actual directory creation.  In particular,
the /data/fonts directory is being created using 'mkdir /data/fonts/'.

The effect is that the mkdir command thinks that /data/fonts/ is *not* a
top-level directory of /data, so it defaults to no encryption action.
Fortunately, the full command happens to use "encryption=Require", so we
dodged a bullet there, though the warning "Inferred action different
from explicit one" is still triggered.

There are a few approaches we could take here, including even just
fixing the /data/fonts/ command specifically, but I think the best
solution is to have mkdir clean its path at the very beginning.  This
retains the Linux path semantics that people expect, while avoiding
surprises in path processing afterwards.  This CL implements that.

Note, this CL intentionally changes the behavior of, and thus would
break, any existing cases where mkdir is used to create a top-level
/data directory using a path with unnecessary slashes and without using
an explicit encryption action.  There are no known cases where this
already occurs, however.  No cases exist in platform code, and vendor
init scripts shouldn't be creating top-level /data directories anyway.

Test: atest CtsInitTestCases
Test: Booted and verified that a trailing slash is no longer present in
      the log message "Verified that /data/fonts/ has the encryption
      policy ...".  Also verified that the message "Inferred action
      different ..." is no longer present just above it.
Bug: 232554803
Change-Id: Ie55c3ac1a2b1cf50632d54a1e565cb98c17b2a6a
2022-05-13 19:29:00 +00:00

110 lines
3.5 KiB
C++

/*
* Copyright (C) 2010 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.
*/
#pragma once
#include <sys/stat.h>
#include <sys/types.h>
#include <chrono>
#include <functional>
#include <string>
#include <vector>
#include <android-base/chrono_utils.h>
#include "fscrypt_init_extensions.h"
#include "result.h"
using android::base::boot_clock;
namespace android {
namespace init {
enum mount_mode {
MOUNT_MODE_DEFAULT = 0,
MOUNT_MODE_EARLY = 1,
MOUNT_MODE_LATE = 2,
};
static const char kColdBootDoneProp[] = "ro.cold_boot_done";
extern void (*trigger_shutdown)(const std::string& command);
Result<int> CreateSocket(const std::string& name, int type, bool passcred, mode_t perm, uid_t uid,
gid_t gid, const std::string& socketcon);
Result<std::string> ReadFile(const std::string& path);
Result<void> WriteFile(const std::string& path, const std::string& content);
Result<uid_t> DecodeUid(const std::string& name);
bool mkdir_recursive(const std::string& pathname, mode_t mode);
int wait_for_file(const char *filename, std::chrono::nanoseconds timeout);
void ImportKernelCmdline(const std::function<void(const std::string&, const std::string&)>&);
void ImportBootconfig(const std::function<void(const std::string&, const std::string&)>&);
bool make_dir(const std::string& path, mode_t mode);
bool is_dir(const char* pathname);
Result<std::string> ExpandProps(const std::string& src);
// Returns the platform's Android DT directory as specified in the kernel cmdline.
// If the platform does not configure a custom DT path, returns the standard one (based in procfs).
const std::string& get_android_dt_dir();
// Reads or compares the content of device tree file under the platform's Android DT directory.
bool read_android_dt_file(const std::string& sub_path, std::string* dt_content);
bool is_android_dt_value_expected(const std::string& sub_path, const std::string& expected_content);
bool IsLegalPropertyName(const std::string& name);
Result<void> IsLegalPropertyValue(const std::string& name, const std::string& value);
std::string CleanDirPath(const std::string& path);
struct MkdirOptions {
std::string target;
mode_t mode;
uid_t uid;
gid_t gid;
FscryptAction fscrypt_action;
std::string ref_option;
};
Result<MkdirOptions> ParseMkdir(const std::vector<std::string>& args);
struct MountAllOptions {
std::vector<std::string> rc_paths;
std::string fstab_path;
mount_mode mode;
bool import_rc;
};
Result<MountAllOptions> ParseMountAll(const std::vector<std::string>& args);
Result<std::pair<int, std::vector<std::string>>> ParseRestorecon(
const std::vector<std::string>& args);
Result<std::string> ParseSwaponAll(const std::vector<std::string>& args);
Result<std::string> ParseUmountAll(const std::vector<std::string>& args);
void SetStdioToDevNull(char** argv);
void InitKernelLogging(char** argv);
bool IsRecoveryMode();
bool IsDefaultMountNamespaceReady();
void SetDefaultMountNamespaceReady();
bool IsMicrodroid();
} // namespace init
} // namespace android