diff options
Diffstat (limited to 'common-kex.c')
| -rw-r--r-- | common-kex.c | 73 |
1 files changed, 68 insertions, 5 deletions
diff --git a/common-kex.c b/common-kex.c index a32ca6d..a304d02 100644 --- a/common-kex.c +++ b/common-kex.c @@ -577,7 +577,7 @@ struct kex_dh_param *gen_kexdh_param() { TRACE(("enter gen_kexdh_vals")) struct kex_dh_param *param = m_malloc(sizeof(*param)); - m_mp_init_multi(¶m->pub, ¶m->priv, NULL); + m_mp_init_multi(¶m->pub, ¶m->priv, &dh_g, &dh_p, &dh_q, NULL); /* read the prime and generator*/ load_dh_p(&dh_p); @@ -690,8 +690,8 @@ void kexecdh_comb_key(struct kex_ecdh_param *param, buffer *pub_them, ses.dh_K = dropbear_ecc_shared_secret(Q_them, ¶m->key); - /* From here on, the code needs to work with the _same_ vars on each side, - * not vice-versaing for client/server */ + /* Create the remainder of the hash buffer, to generate the exchange hash + See RFC5656 section 4 page 7 */ if (IS_DROPBEAR_CLIENT) { Q_C = ¶m->key; Q_S = Q_them; @@ -700,7 +700,6 @@ void kexecdh_comb_key(struct kex_ecdh_param *param, buffer *pub_them, Q_S = ¶m->key; } - /* Create the remainder of the hash buffer, to generate the exchange hash */ /* K_S, the host key */ buf_put_pub_key(ses.kexhashbuf, hostkey, ses.newkeys->algo_hostkey); /* Q_C, client's ephemeral public key octet string */ @@ -713,7 +712,71 @@ void kexecdh_comb_key(struct kex_ecdh_param *param, buffer *pub_them, /* calculate the hash H to sign */ finish_kexhashbuf(); } -#endif +#endif /* DROPBEAR_ECDH */ + +#ifdef DROPBEAR_CURVE25519 +struct kex_curve25519_param *gen_kexcurve25519_param () { + /* Per http://cr.yp.to/ecdh.html */ + struct kex_curve25519_param *param = m_malloc(sizeof(*param)); + const unsigned char basepoint[32] = {9}; + + genrandom(param->priv, CURVE25519_LEN); + param->priv[0] &= 248; + param->priv[31] &= 127; + param->priv[31] |= 64; + + curve25519_donna(param->pub, param->priv, basepoint); + + return param; +} + +void free_kexcurve25519_param(struct kex_curve25519_param *param) +{ + m_burn(param->priv, CURVE25519_LEN); + m_free(param); +} + +void kexcurve25519_comb_key(struct kex_curve25519_param *param, buffer *buf_pub_them, + sign_key *hostkey) { + unsigned char out[CURVE25519_LEN]; + const unsigned char* Q_C = NULL; + const unsigned char* Q_S = NULL; + + if (buf_pub_them->len != CURVE25519_LEN) + { + dropbear_exit("Bad curve25519"); + } + + curve25519_donna(out, param->priv, buf_pub_them->data); + m_mp_alloc_init_multi(&ses.dh_K, NULL); + bytes_to_mp(ses.dh_K, out, CURVE25519_LEN); + m_burn(out, sizeof(out)); + + /* Create the remainder of the hash buffer, to generate the exchange hash. + See RFC5656 section 4 page 7 */ + if (IS_DROPBEAR_CLIENT) { + Q_C = param->pub; + Q_S = buf_pub_them->data; + } else { + Q_S = param->pub; + Q_C = buf_pub_them->data; + } + + /* K_S, the host key */ + buf_put_pub_key(ses.kexhashbuf, hostkey, ses.newkeys->algo_hostkey); + /* Q_C, client's ephemeral public key octet string */ + buf_putstring(ses.kexhashbuf, Q_C, CURVE25519_LEN); + /* Q_S, server's ephemeral public key octet string */ + buf_putstring(ses.kexhashbuf, Q_S, CURVE25519_LEN); + /* K, the shared secret */ + buf_putmpint(ses.kexhashbuf, ses.dh_K); + + /* calculate the hash H to sign */ + finish_kexhashbuf(); +} +#endif /* DROPBEAR_CURVE25519 */ + + static void finish_kexhashbuf(void) { hash_state hs; |