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/*
* Unix EntropySource
* (C) 1999-2009,2013 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#ifndef BOTAN_ENTROPY_SRC_UNIX_H__
#define BOTAN_ENTROPY_SRC_UNIX_H__
#include <botan/entropy_src.h>
#include <vector>
#include <mutex>
namespace Botan {
/**
* Entropy source for generic Unix. Runs various programs trying to
* gather data hard for a remote attacker to guess. Probably not too
* effective against local attackers as they can sample from the same
* distribution.
*/
class Unix_EntropySource : public EntropySource
{
public:
std::string name() const { return "Unix Process Runner"; }
void poll(Entropy_Accumulator& accum) override;
/**
* @param trusted_paths is a list of directories that are assumed
* to contain only 'safe' binaries. If an attacker can write
* an executable to one of these directories then we will
* run arbitrary code.
*/
Unix_EntropySource(const std::vector<std::string>& trusted_paths,
size_t concurrent_processes = 0);
private:
static std::vector<std::vector<std::string>> get_default_sources();
class Unix_Process
{
public:
int fd() const { return m_fd; }
void spawn(const std::vector<std::string>& args);
void shutdown();
Unix_Process() {}
Unix_Process(const std::vector<std::string>& args) { spawn(args); }
~Unix_Process() { shutdown(); }
Unix_Process(Unix_Process&& other)
{
std::swap(m_fd, other.m_fd);
std::swap(m_pid, other.m_pid);
}
Unix_Process(const Unix_Process&) = delete;
Unix_Process& operator=(const Unix_Process&) = delete;
private:
int m_fd = -1;
int m_pid = -1;
};
const std::vector<std::string>& next_source();
std::mutex m_mutex;
const std::vector<std::string> m_trusted_paths;
const size_t m_concurrent;
std::vector<std::vector<std::string>> m_sources;
size_t m_sources_idx = 0;
std::vector<Unix_Process> m_procs;
};
class UnixProcessInfo_EntropySource : public EntropySource
{
public:
std::string name() const { return "Unix Process Info"; }
void poll(Entropy_Accumulator& accum);
};
}
#endif
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