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rocksdb/env/env_chroot.cc

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12 KiB

// Copyright (c) 2016-present, Facebook, Inc. All rights reserved.
// This source code is licensed under both the GPLv2 (found in the
// COPYING file in the root directory) and Apache 2.0 License
// (found in the LICENSE.Apache file in the root directory).
#if !defined(ROCKSDB_LITE) && !defined(OS_WIN)
#include "env/env_chroot.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <string>
#include <utility>
#include <vector>
#include "rocksdb/status.h"
namespace ROCKSDB_NAMESPACE {
class ChrootEnv : public EnvWrapper {
public:
ChrootEnv(Env* base_env, const std::string& chroot_dir)
: EnvWrapper(base_env) {
#if defined(OS_AIX)
char resolvedName[PATH_MAX];
char* real_chroot_dir = realpath(chroot_dir.c_str(), resolvedName);
#else
char* real_chroot_dir = realpath(chroot_dir.c_str(), nullptr);
#endif
// chroot_dir must exist so realpath() returns non-nullptr.
assert(real_chroot_dir != nullptr);
chroot_dir_ = real_chroot_dir;
#if !defined(OS_AIX)
free(real_chroot_dir);
#endif
}
Status NewSequentialFile(const std::string& fname,
std::unique_ptr<SequentialFile>* result,
const EnvOptions& options) override {
auto status_and_enc_path = EncodePathWithNewBasename(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::NewSequentialFile(status_and_enc_path.second, result,
options);
}
Status NewRandomAccessFile(const std::string& fname,
std::unique_ptr<RandomAccessFile>* result,
const EnvOptions& options) override {
auto status_and_enc_path = EncodePathWithNewBasename(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::NewRandomAccessFile(status_and_enc_path.second, result,
options);
}
Status NewWritableFile(const std::string& fname,
std::unique_ptr<WritableFile>* result,
const EnvOptions& options) override {
auto status_and_enc_path = EncodePathWithNewBasename(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::NewWritableFile(status_and_enc_path.second, result,
options);
}
Status ReuseWritableFile(const std::string& fname,
const std::string& old_fname,
std::unique_ptr<WritableFile>* result,
const EnvOptions& options) override {
auto status_and_enc_path = EncodePathWithNewBasename(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
auto status_and_old_enc_path = EncodePath(old_fname);
if (!status_and_old_enc_path.first.ok()) {
return status_and_old_enc_path.first;
}
return EnvWrapper::ReuseWritableFile(status_and_old_enc_path.second,
status_and_old_enc_path.second, result,
options);
}
Status NewRandomRWFile(const std::string& fname,
std::unique_ptr<RandomRWFile>* result,
const EnvOptions& options) override {
auto status_and_enc_path = EncodePathWithNewBasename(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::NewRandomRWFile(status_and_enc_path.second, result,
options);
}
Status NewDirectory(const std::string& dir,
std::unique_ptr<Directory>* result) override {
auto status_and_enc_path = EncodePathWithNewBasename(dir);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::NewDirectory(status_and_enc_path.second, result);
}
Status FileExists(const std::string& fname) override {
auto status_and_enc_path = EncodePathWithNewBasename(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::FileExists(status_and_enc_path.second);
}
Status GetChildren(const std::string& dir,
std::vector<std::string>* result) override {
auto status_and_enc_path = EncodePath(dir);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::GetChildren(status_and_enc_path.second, result);
}
Status GetChildrenFileAttributes(
const std::string& dir, std::vector<FileAttributes>* result) override {
auto status_and_enc_path = EncodePath(dir);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::GetChildrenFileAttributes(status_and_enc_path.second,
result);
}
Status DeleteFile(const std::string& fname) override {
auto status_and_enc_path = EncodePath(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::DeleteFile(status_and_enc_path.second);
}
Status CreateDir(const std::string& dirname) override {
auto status_and_enc_path = EncodePathWithNewBasename(dirname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::CreateDir(status_and_enc_path.second);
}
Status CreateDirIfMissing(const std::string& dirname) override {
auto status_and_enc_path = EncodePathWithNewBasename(dirname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::CreateDirIfMissing(status_and_enc_path.second);
}
Status DeleteDir(const std::string& dirname) override {
auto status_and_enc_path = EncodePath(dirname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::DeleteDir(status_and_enc_path.second);
}
Status GetFileSize(const std::string& fname, uint64_t* file_size) override {
auto status_and_enc_path = EncodePath(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::GetFileSize(status_and_enc_path.second, file_size);
}
Status GetFileModificationTime(const std::string& fname,
uint64_t* file_mtime) override {
auto status_and_enc_path = EncodePath(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::GetFileModificationTime(status_and_enc_path.second,
file_mtime);
}
Status RenameFile(const std::string& src, const std::string& dest) override {
auto status_and_src_enc_path = EncodePath(src);
if (!status_and_src_enc_path.first.ok()) {
return status_and_src_enc_path.first;
}
auto status_and_dest_enc_path = EncodePathWithNewBasename(dest);
if (!status_and_dest_enc_path.first.ok()) {
return status_and_dest_enc_path.first;
}
return EnvWrapper::RenameFile(status_and_src_enc_path.second,
status_and_dest_enc_path.second);
}
Status LinkFile(const std::string& src, const std::string& dest) override {
auto status_and_src_enc_path = EncodePath(src);
if (!status_and_src_enc_path.first.ok()) {
return status_and_src_enc_path.first;
}
auto status_and_dest_enc_path = EncodePathWithNewBasename(dest);
if (!status_and_dest_enc_path.first.ok()) {
return status_and_dest_enc_path.first;
}
return EnvWrapper::LinkFile(status_and_src_enc_path.second,
status_and_dest_enc_path.second);
}
Status LockFile(const std::string& fname, FileLock** lock) override {
auto status_and_enc_path = EncodePathWithNewBasename(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
// FileLock subclasses may store path (e.g., PosixFileLock stores it). We
// can skip stripping the chroot directory from this path because callers
// shouldn't use it.
return EnvWrapper::LockFile(status_and_enc_path.second, lock);
}
Status GetTestDirectory(std::string* path) override {
// Adapted from PosixEnv's implementation since it doesn't provide a way to
// create directory in the chroot.
char buf[256];
snprintf(buf, sizeof(buf), "/rocksdbtest-%d", static_cast<int>(geteuid()));
*path = buf;
// Directory may already exist, so ignore return
CreateDir(*path);
return Status::OK();
}
Status NewLogger(const std::string& fname,
std::shared_ptr<Logger>* result) override {
auto status_and_enc_path = EncodePathWithNewBasename(fname);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::NewLogger(status_and_enc_path.second, result);
}
Status GetAbsolutePath(const std::string& db_path,
std::string* output_path) override {
auto status_and_enc_path = EncodePath(db_path);
if (!status_and_enc_path.first.ok()) {
return status_and_enc_path.first;
}
return EnvWrapper::GetAbsolutePath(status_and_enc_path.second, output_path);
}
private:
// Returns status and expanded absolute path including the chroot directory.
// Checks whether the provided path breaks out of the chroot. If it returns
// non-OK status, the returned path should not be used.
std::pair<Status, std::string> EncodePath(const std::string& path) {
if (path.empty() || path[0] != '/') {
return {Status::InvalidArgument(path, "Not an absolute path"), ""};
}
std::pair<Status, std::string> res;
res.second = chroot_dir_ + path;
#if defined(OS_AIX)
char resolvedName[PATH_MAX];
char* normalized_path = realpath(res.second.c_str(), resolvedName);
#else
char* normalized_path = realpath(res.second.c_str(), nullptr);
#endif
if (normalized_path == nullptr) {
res.first = Status::NotFound(res.second, strerror(errno));
} else if (strlen(normalized_path) < chroot_dir_.size() ||
strncmp(normalized_path, chroot_dir_.c_str(),
chroot_dir_.size()) != 0) {
res.first = Status::IOError(res.second,
"Attempted to access path outside chroot");
} else {
res.first = Status::OK();
}
#if !defined(OS_AIX)
free(normalized_path);
#endif
return res;
}
// Similar to EncodePath() except assumes the basename in the path hasn't been
// created yet.
std::pair<Status, std::string> EncodePathWithNewBasename(
const std::string& path) {
if (path.empty() || path[0] != '/') {
return {Status::InvalidArgument(path, "Not an absolute path"), ""};
}
// Basename may be followed by trailing slashes
size_t final_idx = path.find_last_not_of('/');
if (final_idx == std::string::npos) {
// It's only slashes so no basename to extract
return EncodePath(path);
}
// Pull off the basename temporarily since realname(3) (used by
// EncodePath()) requires a path that exists
size_t base_sep = path.rfind('/', final_idx);
auto status_and_enc_path = EncodePath(path.substr(0, base_sep + 1));
status_and_enc_path.second.append(path.substr(base_sep + 1));
return status_and_enc_path;
}
std::string chroot_dir_;
};
Env* NewChrootEnv(Env* base_env, const std::string& chroot_dir) {
if (!base_env->FileExists(chroot_dir).ok()) {
return nullptr;
}
return new ChrootEnv(base_env, chroot_dir);
}
} // namespace ROCKSDB_NAMESPACE
#endif // !defined(ROCKSDB_LITE) && !defined(OS_WIN)