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Fix rename() when overwriting an existing file: (a) Keep the invariant that the list of directory entries is sorted and (b) delete the blob of the overwritten file

This commit is contained in:
Sebastian Messmer 2016-04-25 17:42:17 -07:00
parent 40f27acafc
commit 811c163bfa
13 changed files with 117 additions and 17 deletions
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4
src/cryfs/filesystem/CryDevice.cpp
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@ -205,4 +205,8 @@ void CryDevice::callFsActionCallbacks() const {
}
}
uint64_t CryDevice::numBlocks() const {
return _fsBlobStore->numBlocks();
}
}

2
src/cryfs/filesystem/CryDevice.h
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@ -35,6 +35,8 @@ public:
void callFsActionCallbacks() const;
uint64_t numBlocks() const;
private:
cpputils::unique_ref<parallelaccessfsblobstore::ParallelAccessFsBlobStore> _fsBlobStore;

5
src/cryfs/filesystem/CryNode.cpp
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@ -64,8 +64,11 @@ void CryNode::rename(const bf::path &to) {
}
std::string oldName = old->name(); // Store, because if targetDir == *_parent, then the 'old' object will be invalidated after we add something to targetDir
if (targetDir->key() != (*_parent)->key() || oldName != to.filename().native()) {
auto onOverwritten = [this] (const blockstore::Key &key) {
device()->RemoveBlob(key);
};
targetDir->AddOrOverwriteChild(to.filename().native(), old->key(), old->type(), old->mode(), old->uid(), old->gid(),
old->lastAccessTime(), old->lastModificationTime());
old->lastAccessTime(), old->lastModificationTime(), onOverwritten);
(*_parent)->RemoveChild(oldName);
}
}

3
src/cryfs/filesystem/CryNode.h
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@ -12,6 +12,8 @@ namespace cryfs {
class CryNode: public virtual fspp::Node {
public:
virtual ~CryNode();
CryNode(CryDevice *device, boost::optional<cpputils::unique_ref<parallelaccessfsblobstore::DirBlobRef>> parent, const blockstore::Key &key);
void access(int mask) const override;
void stat(struct ::stat *result) const override;
@ -22,7 +24,6 @@ public:
protected:
CryNode();
virtual ~CryNode();
CryDevice *device();
const CryDevice *device() const;

5
src/cryfs/filesystem/cachingfsblobstore/DirBlobRef.h
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@ -43,8 +43,9 @@ public:
}
void AddOrOverwriteChild(const std::string &name, const blockstore::Key &blobKey, fspp::Dir::EntryType type,
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime) {
return _base->AddOrOverwriteChild(name, blobKey, type, mode, uid, gid, lastAccessTime, lastModificationTime);
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime,
std::function<void (const blockstore::Key &key)> onOverwritten) {
return _base->AddOrOverwriteChild(name, blobKey, type, mode, uid, gid, lastAccessTime, lastModificationTime, onOverwritten);
}
void statChild(const blockstore::Key &key, struct ::stat *result) const {

12
src/cryfs/filesystem/fsblobstore/DirBlob.cpp
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@ -65,28 +65,32 @@ void DirBlob::_readEntriesFromBlob() {
}
void DirBlob::AddChildDir(const std::string &name, const Key &blobKey, mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime) {
std::unique_lock<std::mutex> lock(_mutex);
_addChild(name, blobKey, fspp::Dir::EntryType::DIR, mode, uid, gid, lastAccessTime, lastModificationTime);
}
void DirBlob::AddChildFile(const std::string &name, const Key &blobKey, mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime) {
std::unique_lock<std::mutex> lock(_mutex);
_addChild(name, blobKey, fspp::Dir::EntryType::FILE, mode, uid, gid, lastAccessTime, lastModificationTime);
}
void DirBlob::AddChildSymlink(const std::string &name, const blockstore::Key &blobKey, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime) {
std::unique_lock<std::mutex> lock(_mutex);
_addChild(name, blobKey, fspp::Dir::EntryType::SYMLINK, S_IFLNK | S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH, uid, gid, lastAccessTime, lastModificationTime);
}
void DirBlob::_addChild(const std::string &name, const Key &blobKey,
fspp::Dir::EntryType entryType, mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime) {
std::unique_lock<std::mutex> lock(_mutex);
_entries.add(name, blobKey, entryType, mode, uid, gid, lastAccessTime, lastModificationTime);
_changed = true;
}
void DirBlob::AddOrOverwriteChild(const std::string &name, const Key &blobKey,
fspp::Dir::EntryType entryType, mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime) {
void DirBlob::AddOrOverwriteChild(const std::string &name, const Key &blobKey, fspp::Dir::EntryType entryType,
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime,
std::function<void (const blockstore::Key &key)> onOverwritten) {
std::unique_lock<std::mutex> lock(_mutex);
_entries.addOrOverwrite(name, blobKey, entryType, mode, uid, gid, lastAccessTime, lastModificationTime);
_entries.addOrOverwrite(name, blobKey, entryType, mode, uid, gid, lastAccessTime, lastModificationTime, onOverwritten);
_changed = true;
}

3
src/cryfs/filesystem/fsblobstore/DirBlob.h
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@ -44,7 +44,8 @@ namespace cryfs {
void AddChildSymlink(const std::string &name, const blockstore::Key &blobKey, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime);
void AddOrOverwriteChild(const std::string &name, const blockstore::Key &blobKey, fspp::Dir::EntryType type,
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime);
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime,
std::function<void (const blockstore::Key &key)> onOverwritten);
void RemoveChild(const std::string &name);

13
src/cryfs/filesystem/fsblobstore/utils/DirEntryList.cpp
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@ -61,16 +61,18 @@ void DirEntryList::_add(const string &name, const Key &blobKey, fspp::Dir::Entry
}
void DirEntryList::addOrOverwrite(const string &name, const Key &blobKey, fspp::Dir::EntryType entryType, mode_t mode,
uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime) {
uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime,
std::function<void (const blockstore::Key &key)> onOverwritten) {
auto found = _findByName(name);
if (found != _entries.end()) {
_overwrite(&*found, name, blobKey, entryType, mode, uid, gid, lastAccessTime, lastModificationTime);
onOverwritten(found->key());
_overwrite(found, name, blobKey, entryType, mode, uid, gid, lastAccessTime, lastModificationTime);
} else {
_add(name, blobKey, entryType, mode, uid, gid, lastAccessTime, lastModificationTime);
}
}
void DirEntryList::_overwrite(DirEntry *entry, const string &name, const Key &blobKey, fspp::Dir::EntryType entryType, mode_t mode,
void DirEntryList::_overwrite(vector<DirEntry>::iterator entry, const string &name, const Key &blobKey, fspp::Dir::EntryType entryType, mode_t mode,
uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime) {
if (entry->type() != entryType) {
if (entry->type() == fspp::Dir::EntryType::DIR) {
@ -82,7 +84,10 @@ void DirEntryList::_overwrite(DirEntry *entry, const string &name, const Key &bl
throw fspp::fuse::FuseErrnoException(ENOTDIR);
}
}
*entry = DirEntry(entryType, name, blobKey, mode, uid, gid, lastAccessTime, lastModificationTime, time::now());
// The new entry has possibly a different key, so it has to be in a different list position (list is ordered by keys).
// That's why we remove-and-add instead of just modifying the existing entry.
_entries.erase(entry);
_add(name, blobKey, entryType, mode, uid, gid, lastAccessTime, lastModificationTime);
}
boost::optional<const DirEntry&> DirEntryList::get(const string &name) const {

5
src/cryfs/filesystem/fsblobstore/utils/DirEntryList.h
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@ -24,7 +24,8 @@ namespace cryfs {
void add(const std::string &name, const blockstore::Key &blobKey, fspp::Dir::EntryType entryType,
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime);
void addOrOverwrite(const std::string &name, const blockstore::Key &blobKey, fspp::Dir::EntryType entryType,
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime);
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime,
std::function<void (const blockstore::Key &key)> onOverwritten);
boost::optional<const DirEntry&> get(const std::string &name) const;
boost::optional<const DirEntry&> get(const blockstore::Key &key) const;
void remove(const std::string &name);
@ -50,7 +51,7 @@ namespace cryfs {
std::vector<DirEntry>::iterator _findFirst(const blockstore::Key &hint, std::function<bool (const DirEntry&)> pred);
void _add(const std::string &name, const blockstore::Key &blobKey, fspp::Dir::EntryType entryType,
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime);
void _overwrite(DirEntry *entry, const std::string &name, const blockstore::Key &blobKey, fspp::Dir::EntryType entryType,
void _overwrite(std::vector<DirEntry>::iterator entry, const std::string &name, const blockstore::Key &blobKey, fspp::Dir::EntryType entryType,
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime);
std::vector<DirEntry> _entries;

5
src/cryfs/filesystem/parallelaccessfsblobstore/DirBlobRef.h
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@ -39,8 +39,9 @@ public:
}
void AddOrOverwriteChild(const std::string &name, const blockstore::Key &blobKey, fspp::Dir::EntryType type,
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime) {
return _base->AddOrOverwriteChild(name, blobKey, type, mode, uid, gid, lastAccessTime, lastModificationTime);
mode_t mode, uid_t uid, gid_t gid, timespec lastAccessTime, timespec lastModificationTime,
std::function<void (const blockstore::Key &key)> onOverwritten) {
return _base->AddOrOverwriteChild(name, blobKey, type, mode, uid, gid, lastAccessTime, lastModificationTime, onOverwritten);
}
void statChild(const blockstore::Key &key, struct ::stat *result) const {

1
test/cryfs/CMakeLists.txt
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@ -15,6 +15,7 @@ set(SOURCES
config/CryConfigLoaderTest.cpp
config/CryConfigConsoleTest.cpp
filesystem/CryFsTest.cpp
filesystem/CryNodeTest.cpp
filesystem/FileSystemTest.cpp
)

43
test/cryfs/filesystem/CryNodeTest.cpp Normal file
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@ -0,0 +1,43 @@
#include <gtest/gtest.h>
#include "testutils/CryTestBase.h"
#include <cryfs/filesystem/CryDir.h>
#include <cryfs/filesystem/CryFile.h>
#include <cryfs/filesystem/CryOpenFile.h>
using cpputils::unique_ref;
using cpputils::dynamic_pointer_move;
using namespace cryfs;
namespace bf = boost::filesystem;
// Many generic (black box) test cases for FsppNode are covered in Fspp fstest.
// This class adds some tests that need insight into how CryFS works.
class CryNodeTest : public ::testing::Test, public CryTestBase {
public:
static constexpr mode_t MODE_PUBLIC = S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IWGRP | S_IXGRP | S_IROTH | S_IWOTH | S_IXOTH;
unique_ref<CryNode> CreateFile(const bf::path &path) {
auto _parentDir = device().Load(path.parent_path()).value();
auto parentDir = dynamic_pointer_move<CryDir>(_parentDir).value();
parentDir->createAndOpenFile(path.filename().native(), MODE_PUBLIC, 0, 0);
auto createdFile = device().Load(path).value();
return dynamic_pointer_move<CryNode>(createdFile).value();
}
};
TEST_F(CryNodeTest, Rename_DoesntLeaveBlocksOver) {
auto node = CreateFile("/oldname");
EXPECT_EQ(2u, device().numBlocks()); // In the beginning, there is two blocks (the root block and the created file). If that is not true anymore, we'll have to adapt the test case.
node->rename("/newname");
EXPECT_EQ(2u, device().numBlocks()); // Still same number of blocks
}
// TODO Add similar test cases (i.e. checking number of blocks) for other situations in rename, and also for other operations (e.g. deleting files).
TEST_F(CryNodeTest, Rename_Overwrite_DoesntLeaveBlocksOver) {
auto node = CreateFile("/oldname");
CreateFile("/newexistingname");
EXPECT_EQ(3u, device().numBlocks()); // In the beginning, there is three blocks (the root block and the two created files). If that is not true anymore, we'll have to adapt the test case.
node->rename("/newexistingname");
EXPECT_EQ(2u, device().numBlocks()); // Only the blocks of one file are left
}

33
test/cryfs/filesystem/testutils/CryTestBase.h Normal file
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@ -0,0 +1,33 @@
#ifndef MESSMER_CRYFS_TEST_CRYFS_FILESYSTEM_CRYTESTBASE_H
#define MESSMER_CRYFS_TEST_CRYFS_FILESYSTEM_CRYTESTBASE_H
#include <cryfs/filesystem/CryDevice.h>
#include <blockstore/implementations/testfake/FakeBlockStore.h>
#include <cpp-utils/tempfile/TempFile.h>
#include <cpp-utils/crypto/kdf/Scrypt.h>
class CryTestBase {
public:
CryTestBase(): _configFile(false), _device(nullptr) {
auto fakeBlockStore = cpputils::make_unique_ref<blockstore::testfake::FakeBlockStore>();
_device = std::make_unique<cryfs::CryDevice>(configFile(), std::move(fakeBlockStore));
}
cryfs::CryConfigFile configFile() {
cryfs::CryConfig config;
config.SetCipher("aes-256-gcm");
config.SetEncryptionKey(cpputils::AES256_GCM::CreateKey(cpputils::Random::PseudoRandom()).ToString());
config.SetBlocksizeBytes(10240);
return cryfs::CryConfigFile::create(_configFile.path(), std::move(config), "mypassword", cpputils::SCrypt::TestSettings);
}
cryfs::CryDevice &device() {
return *_device;
}
private:
cpputils::TempFile _configFile;
std::unique_ptr<cryfs::CryDevice> _device;
};
#endif