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/*
* (C) 2015,2017 Jack Lloyd
*
* Botan is released under the Simplified BSD License (see license.txt)
*/
#include "cli.h"
#include <botan/rng.h>
#include <botan/entropy_src.h>
#include <botan/hex.h>
#include <botan/parsing.h>
#if defined(BOTAN_HAS_AUTO_SEEDING_RNG)
#include <botan/auto_rng.h>
#endif
#if defined(BOTAN_HAS_SYSTEM_RNG)
#include <botan/system_rng.h>
#endif
#if defined(BOTAN_HAS_PROCESSOR_RNG)
#include <botan/processor_rng.h>
#endif
#if defined(BOTAN_HAS_HMAC_DRBG)
#include <botan/hmac_drbg.h>
#endif
namespace Botan_CLI {
std::unique_ptr<Botan::RandomNumberGenerator>
cli_make_rng(const std::string& rng_type, const std::string& hex_drbg_seed)
{
#if defined(BOTAN_HAS_SYSTEM_RNG)
if(rng_type == "system" || rng_type.empty())
{
return std::unique_ptr<Botan::RandomNumberGenerator>(new Botan::System_RNG);
}
#endif
const std::vector<uint8_t> drbg_seed = Botan::hex_decode(hex_drbg_seed);
#if defined(BOTAN_HAS_AUTO_SEEDING_RNG)
if(rng_type == "auto" || rng_type == "entropy" || rng_type.empty())
{
std::unique_ptr<Botan::RandomNumberGenerator> rng;
if(rng_type == "entropy")
rng.reset(new Botan::AutoSeeded_RNG(Botan::Entropy_Sources::global_sources()));
else
rng.reset(new Botan::AutoSeeded_RNG);
if(drbg_seed.size() > 0)
rng->add_entropy(drbg_seed.data(), drbg_seed.size());
return rng;
}
#endif
#if defined(BOTAN_HAS_HMAC_DRBG) && defined(BOTAN_HAS_SHA2_32)
if(rng_type == "drbg" || (rng_type.empty() && drbg_seed.empty() == false))
{
std::unique_ptr<Botan::MessageAuthenticationCode> mac =
Botan::MessageAuthenticationCode::create_or_throw("HMAC(SHA-256)");
std::unique_ptr<Botan::Stateful_RNG> rng(new Botan::HMAC_DRBG(std::move(mac)));
rng->add_entropy(drbg_seed.data(), drbg_seed.size());
if(rng->is_seeded() == false)
throw CLI_Error("For " + rng->name() + " a seed of at least " +
std::to_string(rng->security_level()/8) +
" bytes must be provided");
return std::unique_ptr<Botan::RandomNumberGenerator>(rng.release());
}
#endif
#if defined(BOTAN_HAS_PROCESSOR_RNG)
if(rng_type == "rdrand" || rng_type == "cpu" || rng_type.empty())
{
if(Botan::Processor_RNG::available())
return std::unique_ptr<Botan::RandomNumberGenerator>(new Botan::Processor_RNG);
else if(rng_type.empty() == false)
throw CLI_Error("RNG instruction not supported on this processor");
}
#endif
if(rng_type.empty())
throw CLI_Error_Unsupported("No random number generator seems to be available in the current build");
else
throw CLI_Error_Unsupported("RNG", rng_type);
}
class RNG final : public Command
{
public:
RNG() : Command("rng --format=hex --system --rdrand --auto --entropy --drbg --drbg-seed= *bytes") {}
std::string group() const override
{
return "misc";
}
std::string description() const override
{
return "Sample random bytes from the specified rng";
}
void go() override
{
const std::string format = get_arg("format");
std::string type = get_arg("rng-type");
if(type.empty())
{
for(std::string flag : { "system", "rdrand", "auto", "entropy", "drbg" })
{
if(flag_set(flag))
{
type = flag;
break;
}
}
}
const std::string drbg_seed = get_arg("drbg-seed");
std::unique_ptr<Botan::RandomNumberGenerator> rng = cli_make_rng(type, drbg_seed);
for(const std::string& req : get_arg_list("bytes"))
{
const size_t req_len = Botan::to_u32bit(req);
const auto blob = rng->random_vec(req_len);
if(format == "binary" || format == "raw")
{
output().write(reinterpret_cast<const char*>(blob.data()), blob.size());
}
else
{
output() << format_blob(format, blob) << "\n";
}
}
}
};
BOTAN_REGISTER_COMMAND("rng", RNG);
}