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// OpenVPN -- An application to securely tunnel IP networks
// over a single port, with support for SSL/TLS-based
// session authentication and key exchange,
// packet encryption, packet authentication, and
// packet compression.
//
// Copyright (C) 2012- OpenVPN Inc.
//
// SPDX-License-Identifier: MPL-2.0 OR AGPL-3.0-only WITH openvpn3-openssl-exception
//
#pragma once
#include <string>
#include <cstring> // for std::strlen, and std::memset
#include <ostream>
#include <openvpn/common/strneq.hpp>
#include <openvpn/buffer/buffer.hpp>
#include <openvpn/buffer/bufstr.hpp>
namespace openvpn {
/**
@brief A string-like type that clears the buffer contents on delete
*/
class SafeString
{
static constexpr size_t INITIAL_CAPACITY = 32;
static constexpr unsigned int BUF_FLAGS = BufAllocFlags::DESTRUCT_ZERO | BufAllocFlags::GROW;
public:
SafeString()
{
}
SafeString(const char *str, const size_t size)
: data(size + 1, BUF_FLAGS)
{
if (size == std::numeric_limits<size_t>::max())
OPENVPN_BUFFER_THROW(buffer_overflow)
data.write((unsigned char *)str, size);
trail();
}
SafeString(const char *str)
: SafeString(str, std::strlen(str))
{
}
SafeString(const std::string &str)
: SafeString(str.c_str(), str.length())
{
}
const char *c_str() const
{
if (data.defined())
return (const char *)data.c_data();
else
return "";
}
// Note: unsafe because of conversion to std::string
std::string to_string() const
{
return buf_to_string(data);
}
size_t length() const
{
return data.size();
}
bool empty() const
{
return !length();
}
char &operator[](size_t pos)
{
return *reinterpret_cast<char *>(data.index(pos));
}
const char &operator[](size_t pos) const
{
return *reinterpret_cast<const char *>(data.c_index(pos));
}
bool operator==(const char *str) const
{
return !operator!=(str);
}
bool operator!=(const char *str) const
{
return crypto::str_neq(str, c_str());
}
bool operator==(const std::string &str) const
{
return !operator!=(str);
}
bool operator!=(const std::string &str) const
{
return crypto::str_neq(str.c_str(), c_str());
}
SafeString &operator+=(char c)
{
alloc();
data.push_back((unsigned char)c);
trail();
return *this;
}
SafeString &operator+=(const char *s)
{
return append(s);
}
SafeString &operator+=(const SafeString &str)
{
return append(str);
}
SafeString &append(const char *s)
{
alloc();
data.write((unsigned char *)s, std::strlen(s));
trail();
return *this;
}
SafeString &append(const SafeString &str)
{
alloc();
data.append(str.data);
trail();
return *this;
}
SafeString &append(const SafeString &str, size_t subpos, size_t sublen)
{
alloc();
data.append(str.data.range(subpos, sublen));
trail();
return *this;
}
void reserve(const size_t n)
{
if (data.allocated())
data.reserve(n + 1);
else
data.init(n + 1, BUF_FLAGS);
}
void wipe()
{
data.clear();
}
private:
void alloc()
{
if (!data.allocated())
data.init(INITIAL_CAPACITY, BUF_FLAGS);
}
void trail()
{
data.set_trailer(0);
}
BufferAllocated data;
};
template <typename Elem, typename Traits>
std::basic_ostream<Elem, Traits> &operator<<(std::basic_ostream<Elem, Traits> &os,
const SafeString &ss)
{
os << ss.c_str();
return os;
}
} // namespace openvpn
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