lokinet/llarp/crypto/crypto_libsodium.cpp
2019-08-12 16:52:58 +01:00

403 lines
11 KiB
C++

#include <crypto/crypto_libsodium.hpp>
#include <sodium/crypto_generichash.h>
#include <sodium/crypto_sign.h>
#include <sodium/crypto_scalarmult.h>
#include <sodium/crypto_stream_xchacha20.h>
#include <util/mem.hpp>
#include <cassert>
extern "C"
{
extern int
sodium_init(void);
}
#include "ec.hpp"
namespace llarp
{
namespace sodium
{
static bool
dh(llarp::SharedSecret &out, const PubKey &client_pk,
const PubKey &server_pk, const uint8_t *themPub, const SecretKey &usSec)
{
llarp::SharedSecret shared;
crypto_generichash_state h;
if(crypto_scalarmult_curve25519(shared.data(), usSec.data(), themPub))
{
return false;
}
crypto_generichash_blake2b_init(&h, nullptr, 0U, shared.size());
crypto_generichash_blake2b_update(&h, client_pk.data(), 32);
crypto_generichash_blake2b_update(&h, server_pk.data(), 32);
crypto_generichash_blake2b_update(&h, shared.data(), 32);
crypto_generichash_blake2b_final(&h, out.data(), shared.size());
return true;
}
static bool
dh_client_priv(llarp::SharedSecret &shared, const PubKey &pk,
const SecretKey &sk, const TunnelNonce &n)
{
llarp::SharedSecret dh_result;
if(dh(dh_result, sk.toPublic(), pk, pk.data(), sk))
{
return crypto_generichash_blake2b(shared.data(), 32, n.data(), 32,
dh_result.data(), 32)
!= -1;
}
llarp::LogWarn("crypto::dh_client - dh failed");
return false;
}
static bool
dh_server_priv(llarp::SharedSecret &shared, const PubKey &pk,
const SecretKey &sk, const TunnelNonce &n)
{
llarp::SharedSecret dh_result;
if(dh(dh_result, pk, sk.toPublic(), pk.data(), sk))
{
return crypto_generichash_blake2b(shared.data(), 32, n.data(), 32,
dh_result.data(), 32)
!= -1;
}
llarp::LogWarn("crypto::dh_server - dh failed");
return false;
}
CryptoLibSodium::CryptoLibSodium()
{
if(sodium_init() == -1)
{
throw std::runtime_error("sodium_init() returned -1");
}
char *avx2 = std::getenv("AVX2_FORCE_DISABLE");
if(avx2 && std::string(avx2) == "1")
{
ntru_init(1);
}
else
{
ntru_init(0);
}
int seed = 0;
randombytes(reinterpret_cast< unsigned char * >(&seed), sizeof(seed));
srand(seed);
}
bool
CryptoLibSodium::xchacha20(const llarp_buffer_t &buff,
const SharedSecret &k, const TunnelNonce &n)
{
return crypto_stream_xchacha20_xor(buff.base, buff.base, buff.sz,
n.data(), k.data())
== 0;
}
bool
CryptoLibSodium::xchacha20_alt(const llarp_buffer_t &out,
const llarp_buffer_t &in,
const SharedSecret &k, const byte_t *n)
{
if(in.sz > out.sz)
return false;
return crypto_stream_xchacha20_xor(out.base, in.base, in.sz, n, k.data())
== 0;
}
bool
CryptoLibSodium::dh_client(llarp::SharedSecret &shared, const PubKey &pk,
const SecretKey &sk, const TunnelNonce &n)
{
return dh_client_priv(shared, pk, sk, n);
}
/// path dh relay side
bool
CryptoLibSodium::dh_server(llarp::SharedSecret &shared, const PubKey &pk,
const SecretKey &sk, const TunnelNonce &n)
{
return dh_server_priv(shared, pk, sk, n);
}
/// transport dh client side
bool
CryptoLibSodium::transport_dh_client(llarp::SharedSecret &shared,
const PubKey &pk, const SecretKey &sk,
const TunnelNonce &n)
{
return dh_client_priv(shared, pk, sk, n);
}
/// transport dh server side
bool
CryptoLibSodium::transport_dh_server(llarp::SharedSecret &shared,
const PubKey &pk, const SecretKey &sk,
const TunnelNonce &n)
{
return dh_server_priv(shared, pk, sk, n);
}
bool
CryptoLibSodium::shorthash(ShortHash &result, const llarp_buffer_t &buff)
{
return crypto_generichash_blake2b(result.data(), ShortHash::SIZE,
buff.base, buff.sz, nullptr, 0)
!= -1;
}
bool
CryptoLibSodium::hmac(byte_t *result, const llarp_buffer_t &buff,
const SharedSecret &secret)
{
return crypto_generichash_blake2b(result, HMACSIZE, buff.base, buff.sz,
secret.data(), HMACSECSIZE)
!= -1;
}
using ec_scalar = AlignedBuffer< 32 >;
struct s_comm final
: public AlignedBuffer< LongHash::SIZE + (ec_scalar::SIZE * 2) >
{
byte_t *
H()
{
return data();
}
byte_t *
K()
{
return data() + LongHash::SIZE;
}
byte_t *
C()
{
return data() + LongHash::SIZE + ec_scalar::SIZE;
}
};
static inline bool
IsNonZero(const byte_t *s)
{
return (((int)(s[0] | s[1] | s[2] | s[3] | s[4] | s[5] | s[6] | s[7]
| s[8] | s[9] | s[10] | s[11] | s[12] | s[13] | s[14]
| s[15] | s[16] | s[17] | s[18] | s[19] | s[20] | s[21]
| s[22] | s[23] | s[24] | s[25] | s[26] | s[27] | s[28]
| s[29] | s[30] | s[31])
- 1)
>> 8)
+ 1;
}
static inline bool
less32(const unsigned char *k0, const unsigned char *k1)
{
for(int n = 31; n >= 0; --n)
{
if(k0[n] < k1[n])
return true;
if(k0[n] > k1[n])
return false;
}
return false;
}
static void
rand32_unbais(byte_t *k)
{
// l = 2^252 + 27742317777372353535851937790883648493.
// it fits 15 in 32 bytes
static const unsigned char limit[32] = {
0xe3, 0x6a, 0x67, 0x72, 0x8b, 0xce, 0x13, 0x29, 0x8f, 0x30, 0x82,
0x8c, 0x0b, 0xa4, 0x10, 0x39, 0x01, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0xf0};
do
{
randombytes(k, 32);
} while(!IsNonZero(k) && !less32(k, limit));
sc25519_reduce32(k);
}
static bool
check_key(const byte_t *k)
{
ge25519_p3 p;
return ge25519_frombytes_vartime(&p, k) == 0;
}
template < typename T, size_t outsz = ec_scalar::SIZE >
static inline bool
hash_to_scalar(const T &in, byte_t *out)
{
if(crypto_generichash_blake2b(out, outsz, in.data(), in.size(), nullptr,
0)
== -1)
return false;
sc25519_reduce32(out);
return true;
}
static bool
hash(uint8_t *result, const llarp_buffer_t &buff)
{
return crypto_generichash_blake2b(result, HASHSIZE, buff.base, buff.sz,
nullptr, 0)
!= -1;
}
bool
CryptoLibSodium::sign(Signature &sig, const SecretKey &secret,
const llarp_buffer_t &buf)
{
s_comm tmp;
if(!hash(tmp.H(), buf))
return false;
ge25519_p3 tmp3;
ec_scalar K;
const PubKey pk = secret.toPublic();
std::copy_n(pk.begin(), pk.size(), tmp.K());
do
{
rand32_unbais(K.data());
if(((const uint32_t *)(K.data()))[7]
== 0) // we don't want tiny numbers here
continue;
ge25519_scalarmult_base(&tmp3, K.data());
ge25519_p3_tobytes(tmp.C(), &tmp3);
hash_to_scalar(tmp, sig.C());
if(!IsNonZero(sig.C()))
continue;
sc25519_mulsub(sig.R(), sig.C(), secret.data(), K.data());
if(!IsNonZero(sig.R()))
continue;
return true;
} while(true);
}
bool
CryptoLibSodium::verify(const PubKey &pub, const llarp_buffer_t &buf,
const Signature &sig)
{
s_comm tmp;
ge25519_p2 tmp2;
ge25519_p3 tmp3;
ec_scalar C;
std::copy_n(pub.begin(), pub.size(), tmp.K());
if(!hash(tmp.H(), buf))
return false;
if(ge25519_frombytes_vartime(&tmp3, pub.data()) != 0)
return false;
if(sc25519_check(sig.C()) != 0 || sc25519_check(sig.R()) != 0
|| !IsNonZero(sig.C()))
return false;
ge25519_double_scalarmult_base_vartime(&tmp2, sig.C(), &tmp3, sig.R());
ge25519_tobytes(tmp.C(), &tmp2);
static const ec_scalar infinity{{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0}};
if(memcmp(tmp.C(), &infinity, 32) == 0)
return false;
hash_to_scalar(tmp, C.data());
sc25519_sub(C.data(), C.data(), sig.C());
return !IsNonZero(C.data());
}
bool
CryptoLibSodium::seed_to_secretkey(llarp::SecretKey &secret,
const llarp::IdentitySecret &seed)
{
if(sc25519_check(seed.data()) != 0)
return false;
ge25519_p3 A;
std::copy_n(seed.begin(), 32, secret.begin());
ge25519_scalarmult_base(&A, seed.data());
byte_t *pub = secret.data() + 32;
ge25519_p3_tobytes(pub, &A);
return true;
}
void
CryptoLibSodium::randomize(const llarp_buffer_t &buff)
{
randombytes((unsigned char *)buff.base, buff.sz);
}
void
CryptoLibSodium::randbytes(byte_t *ptr, size_t sz)
{
randombytes((unsigned char *)ptr, sz);
}
void
CryptoLibSodium::identity_keygen(llarp::SecretKey &keys)
{
llarp::IdentitySecret seed;
rand32_unbais(seed.data());
seed_to_secretkey(keys, seed);
}
void
CryptoLibSodium::encryption_keygen(llarp::SecretKey &keys)
{
auto d = keys.data();
rand32_unbais(d);
crypto_scalarmult_curve25519_base(d + 32, d);
}
bool
CryptoLibSodium::pqe_encrypt(PQCipherBlock &ciphertext,
SharedSecret &sharedkey,
const PQPubKey &pubkey)
{
return crypto_kem_enc(ciphertext.data(), sharedkey.data(), pubkey.data())
!= -1;
}
bool
CryptoLibSodium::pqe_decrypt(const PQCipherBlock &ciphertext,
SharedSecret &sharedkey,
const byte_t *secretkey)
{
return crypto_kem_dec(sharedkey.data(), ciphertext.data(), secretkey)
!= -1;
}
void
CryptoLibSodium::pqe_keygen(PQKeyPair &keypair)
{
auto d = keypair.data();
crypto_kem_keypair(d + PQ_SECRETKEYSIZE, d);
}
} // namespace sodium
const byte_t *
seckey_topublic(const SecretKey &sec)
{
return sec.data() + 32;
}
const byte_t *
pq_keypair_to_public(const PQKeyPair &k)
{
return k.data() + PQ_SECRETKEYSIZE;
}
const byte_t *
pq_keypair_to_secret(const PQKeyPair &k)
{
return k.data();
}
uint64_t
randint()
{
uint64_t i;
randombytes((byte_t *)&i, sizeof(i));
return i;
}
} // namespace llarp