diff options
Diffstat (limited to 'common-kex.c')
| -rw-r--r-- | common-kex.c | 97 |
1 files changed, 81 insertions, 16 deletions
diff --git a/common-kex.c b/common-kex.c index c153c8f..5d46f79 100644 --- a/common-kex.c +++ b/common-kex.c @@ -36,8 +36,7 @@ #include "runopts.h" /* diffie-hellman-group1-sha1 value for p */ -#define DH_P_1_LEN 128 -static const unsigned char dh_p_1[DH_P_1_LEN] = { +const unsigned char dh_p_1[DH_P_1_LEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2, 0x21, 0x68, 0xC2, 0x34, 0xC4, 0xC6, 0x62, 0x8B, 0x80, 0xDC, 0x1C, 0xD1, 0x29, 0x02, 0x4E, 0x08, 0x8A, 0x67, 0xCC, 0x74, 0x02, 0x0B, 0xBE, 0xA6, @@ -51,8 +50,7 @@ static const unsigned char dh_p_1[DH_P_1_LEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF}; /* diffie-hellman-group14-sha1 value for p */ -#define DH_P_14_LEN 256 -static const unsigned char dh_p_14[DH_P_14_LEN] = { +const unsigned char dh_p_14[DH_P_14_LEN] = { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xC9, 0x0F, 0xDA, 0xA2, 0x21, 0x68, 0xC2, 0x34, 0xC4, 0xC6, 0x62, 0x8B, 0x80, 0xDC, 0x1C, 0xD1, 0x29, 0x02, 0x4E, 0x08, 0x8A, 0x67, 0xCC, 0x74, 0x02, 0x0B, 0xBE, 0xA6, @@ -536,14 +534,8 @@ void recv_msg_kexinit() { static void load_dh_p(mp_int * dh_p) { - switch (ses.newkeys->algo_kex) { - case DROPBEAR_KEX_DH_GROUP1: - bytes_to_mp(dh_p, dh_p_1, DH_P_1_LEN); - break; - case DROPBEAR_KEX_DH_GROUP14: - bytes_to_mp(dh_p, dh_p_14, DH_P_14_LEN); - break; - } + bytes_to_mp(dh_p, ses.newkeys->algo_kex->dh_p_bytes, + ses.newkeys->algo_kex->dh_p_len); } /* Initialises and generate one side of the diffie-hellman key exchange values. @@ -667,11 +659,84 @@ void kexdh_comb_key(struct kex_dh_param *param, mp_int *dh_pub_them, #ifdef DROPBEAR_ECDH struct kex_ecdh_param *gen_kexecdh_param() { struct kex_ecdh_param *param = m_malloc(sizeof(*param)); - if (ecc_make_key_ex(NULL, dropbear_ltc_prng, ¶m->key + if (ecc_make_key_ex(NULL, dropbear_ltc_prng, + ¶m->key, ses.newkeys->algo_kex->ecc_curve) != CRYPT_OK) { + dropbear_exit("ECC error") + } + return param; +} + +void free_kexecdh_param(struct kex_ecdh_param *param) { + ecc_free(¶m->key); + m_free(param); + } -void free_kexecdh_param(struct kex_ecdh_param *param); void kexecdh_comb_key(struct kex_ecdh_param *param, buffer *pub_them, - sign_key *hostkey); + sign_key *hostkey) { + + hash_state hs; + // public keys from client and server + ecc_key *Q_C, *Q_S, *Q_them; + + // XXX load Q_them + + ses.dh_K = dropbear_ecc_shared_secret() + + /* Check that dh_pub_them (dh_e or dh_f) is in the range [1, p-1] */ + if (mp_cmp(dh_pub_them, &dh_p) != MP_LT + || mp_cmp_d(dh_pub_them, 0) != MP_GT) { + dropbear_exit("Diffie-Hellman error"); + } + + /* K = e^y mod p = f^x mod p */ + ses.dh_K = (mp_int*)m_malloc(sizeof(mp_int)); + m_mp_init(ses.dh_K); + if (mp_exptmod(dh_pub_them, ¶m->priv, &dh_p, ses.dh_K) != MP_OKAY) { + dropbear_exit("Diffie-Hellman error"); + } + + /* clear no longer needed vars */ + mp_clear_multi(&dh_p, NULL); + + /* From here on, the code needs to work with the _same_ vars on each side, + * not vice-versaing for client/server */ + if (IS_DROPBEAR_CLIENT) { + dh_e = ¶m->pub; + dh_f = dh_pub_them; + } else { + dh_e = dh_pub_them; + dh_f = ¶m->pub; + } + + /* 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); + /* e, exchange value sent by the client */ + buf_putmpint(ses.kexhashbuf, dh_e); + /* f, exchange value sent by the server */ + buf_putmpint(ses.kexhashbuf, dh_f); + /* K, the shared secret */ + buf_putmpint(ses.kexhashbuf, ses.dh_K); + + /* calculate the hash H to sign */ + sha1_init(&hs); + buf_setpos(ses.kexhashbuf, 0); + sha1_process(&hs, buf_getptr(ses.kexhashbuf, ses.kexhashbuf->len), + ses.kexhashbuf->len); + sha1_done(&hs, ses.hash); + + buf_burn(ses.kexhashbuf); + buf_free(ses.kexhashbuf); + ses.kexhashbuf = NULL; + + /* first time around, we set the session_id to H */ + if (ses.session_id == NULL) { + /* create the session_id, this never needs freeing */ + ses.session_id = (unsigned char*)m_malloc(SHA1_HASH_SIZE); + memcpy(ses.session_id, ses.hash, SHA1_HASH_SIZE); + } + +} #endif /* read the other side's algo list. buf_match_algo is a callback to match @@ -707,7 +772,7 @@ static void read_kex_algos() { goto error; } TRACE(("kex algo %s", algo->name)) - ses.newkeys->algo_kex = algo->val; + ses.newkeys->algo_kex = algo->data; /* server_host_key_algorithms */ algo = ses.buf_match_algo(ses.payload, sshhostkey, &goodguess); |