encfs/encfs/NameIO.cpp
2017-08-05 23:23:09 -07:00

303 lines
8.8 KiB
C++

/*****************************************************************************
* Author: Valient Gough <vgough@pobox.com>
*
*****************************************************************************
* Copyright (c) 2004, Valient Gough
*
* This program is free software: you can redistribute it and/or modify it
* under the terms of the GNU Lesser General Public License as published by the
* Free Software Foundation, either version 3 of the License, or (at your
* option) any later version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
* for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "NameIO.h"
#include "easylogging++.h"
#include <cstring>
// for static build. Need to reference the modules which are registered at
// run-time, to ensure that the linker doesn't optimize them away.
#include <iostream>
#include <map>
#include <utility>
#include "BlockNameIO.h"
#include "CipherKey.h"
#include "Error.h"
#include "Interface.h"
#include "NullNameIO.h"
#include "StreamNameIO.h"
using namespace std;
#define REF_MODULE(TYPE) \
if (!TYPE::Enabled()) cerr << "referenceModule: should never happen\n";
namespace encfs {
static void AddSymbolReferences() {
REF_MODULE(BlockNameIO)
REF_MODULE(StreamNameIO)
REF_MODULE(NullNameIO)
}
struct NameIOAlg {
bool hidden;
NameIO::Constructor constructor;
string description;
Interface iface;
};
using NameIOMap_t = multimap<string, NameIOAlg>;
static NameIOMap_t *gNameIOMap = nullptr;
list<NameIO::Algorithm> NameIO::GetAlgorithmList(bool includeHidden) {
AddSymbolReferences();
list<Algorithm> result;
if (gNameIOMap != nullptr) {
NameIOMap_t::const_iterator it;
NameIOMap_t::const_iterator end = gNameIOMap->end();
for (it = gNameIOMap->begin(); it != end; ++it) {
if (includeHidden || !it->second.hidden) {
Algorithm tmp;
tmp.name = it->first;
tmp.description = it->second.description;
tmp.iface = it->second.iface;
result.push_back(tmp);
}
}
}
return result;
}
bool NameIO::Register(const char *name, const char *description,
const Interface &iface, Constructor constructor,
bool hidden) {
if (gNameIOMap == nullptr) {
gNameIOMap = new NameIOMap_t;
}
NameIOAlg alg;
alg.hidden = hidden;
alg.constructor = constructor;
alg.description = description;
alg.iface = iface;
gNameIOMap->insert(make_pair(string(name), alg));
return true;
}
std::shared_ptr<NameIO> NameIO::New(const string &name,
const std::shared_ptr<Cipher> &cipher,
const CipherKey &key) {
std::shared_ptr<NameIO> result;
if (gNameIOMap != nullptr) {
NameIOMap_t::const_iterator it = gNameIOMap->find(name);
if (it != gNameIOMap->end()) {
Constructor fn = it->second.constructor;
result = (*fn)(it->second.iface, cipher, key);
}
}
return result;
}
std::shared_ptr<NameIO> NameIO::New(const Interface &iface,
const std::shared_ptr<Cipher> &cipher,
const CipherKey &key) {
std::shared_ptr<NameIO> result;
if (gNameIOMap != nullptr) {
NameIOMap_t::const_iterator it;
NameIOMap_t::const_iterator end = gNameIOMap->end();
for (it = gNameIOMap->begin(); it != end; ++it) {
if (it->second.iface.implements(iface)) {
Constructor fn = it->second.constructor;
result = (*fn)(iface, cipher, key);
break;
}
}
}
return result;
}
NameIO::NameIO() : chainedNameIV(false), reverseEncryption(false) {}
NameIO::~NameIO() = default;
void NameIO::setChainedNameIV(bool enable) { chainedNameIV = enable; }
bool NameIO::getChainedNameIV() const { return chainedNameIV; }
void NameIO::setReverseEncryption(bool enable) { reverseEncryption = enable; }
bool NameIO::getReverseEncryption() const { return reverseEncryption; }
std::string NameIO::recodePath(
const char *path, int (NameIO::*_length)(int) const,
int (NameIO::*_code)(const char *, int, uint64_t *, char *, int) const,
uint64_t *iv) const {
string output;
while (*path != 0) {
if (*path == '/') {
if (!output.empty()) { // don't start the string with '/'
output += '/';
}
++path;
} else {
bool isDotFile = (*path == '.');
const char *next = strchr(path, '/');
int len = next != nullptr ? next - path : strlen(path);
// at this point we know that len > 0
if (isDotFile && (path[len - 1] == '.') && (len <= 2)) {
output.append(len, '.'); // append [len] copies of '.'
path += len;
continue;
}
// figure out buffer sizes
int approxLen = (this->*_length)(len);
if (approxLen <= 0) {
throw Error("Filename too small to decode");
}
int bufSize = 0;
BUFFER_INIT_S(codeBuf, 32, (unsigned int)approxLen + 1, bufSize)
// code the name
int codedLen = (this->*_code)(path, len, iv, codeBuf, bufSize);
rAssert(codedLen <= approxLen);
rAssert(codeBuf[codedLen] == '\0');
path += len;
// append result to string
output += (char *)codeBuf;
BUFFER_RESET(codeBuf)
}
}
return output;
}
std::string NameIO::encodePath(const char *plaintextPath) const {
uint64_t iv = 0;
return encodePath(plaintextPath, &iv);
}
std::string NameIO::decodePath(const char *cipherPath) const {
uint64_t iv = 0;
return decodePath(cipherPath, &iv);
}
std::string NameIO::_encodePath(const char *plaintextPath, uint64_t *iv) const {
// if chaining is not enabled, then the iv pointer is not used..
if (!chainedNameIV) {
iv = nullptr;
}
return recodePath(plaintextPath, &NameIO::maxEncodedNameLen,
&NameIO::encodeName, iv);
}
std::string NameIO::_decodePath(const char *cipherPath, uint64_t *iv) const {
// if chaining is not enabled, then the iv pointer is not used..
if (!chainedNameIV) {
iv = nullptr;
}
return recodePath(cipherPath, &NameIO::maxDecodedNameLen, &NameIO::decodeName,
iv);
}
std::string NameIO::encodePath(const char *path, uint64_t *iv) const {
return getReverseEncryption() ? _decodePath(path, iv) : _encodePath(path, iv);
}
std::string NameIO::decodePath(const char *path, uint64_t *iv) const {
return getReverseEncryption() ? _encodePath(path, iv) : _decodePath(path, iv);
}
int NameIO::encodeName(const char *input, int length, char *output,
int bufferLength) const {
return encodeName(input, length, (uint64_t *)nullptr, output, bufferLength);
}
int NameIO::decodeName(const char *input, int length, char *output,
int bufferLength) const {
return decodeName(input, length, (uint64_t *)nullptr, output, bufferLength);
}
std::string NameIO::_encodeName(const char *plaintextName, int length) const {
int approxLen = maxEncodedNameLen(length);
int bufSize = 0;
BUFFER_INIT_S(codeBuf, 32, (unsigned int)approxLen + 1, bufSize)
// code the name
int codedLen = encodeName(plaintextName, length, nullptr, codeBuf, bufSize);
rAssert(codedLen <= approxLen);
rAssert(codeBuf[codedLen] == '\0');
// append result to string
std::string result = (char *)codeBuf;
BUFFER_RESET(codeBuf)
return result;
}
std::string NameIO::_decodeName(const char *encodedName, int length) const {
int approxLen = maxDecodedNameLen(length);
int bufSize = 0;
BUFFER_INIT_S(codeBuf, 32, (unsigned int)approxLen + 1, bufSize)
// code the name
int codedLen = decodeName(encodedName, length, nullptr, codeBuf, bufSize);
rAssert(codedLen <= approxLen);
rAssert(codeBuf[codedLen] == '\0');
// append result to string
std::string result = (char *)codeBuf;
BUFFER_RESET(codeBuf)
return result;
}
std::string NameIO::encodeName(const char *path, int length) const {
return getReverseEncryption() ? _decodeName(path, length)
: _encodeName(path, length);
}
std::string NameIO::decodeName(const char *path, int length) const {
return getReverseEncryption() ? _encodeName(path, length)
: _decodeName(path, length);
}
/*
int NameIO::encodeName( const char *path, int length,
char *output ) const
{
return getReverseEncryption() ?
_decodeName( path, length, output ) :
_encodeName( path, length, output );
}
int NameIO::decodeName( const char *path, int length,
char *output ) const
{
return getReverseEncryption() ?
_encodeName( path, length, output ) :
_decodeName( path, length, output );
}
*/
} // namespace encfs