Mercurial > dropbear
diff common-kex.c @ 839:33207ed1174b
Merge in ECC
author | Matt Johnston <matt@ucc.asn.au> |
---|---|
date | Mon, 21 Oct 2013 22:57:21 +0800 |
parents | 724c3e0c8734 |
children | 6c69e7df3621 |
line wrap: on
line diff
--- a/common-kex.c Wed Oct 16 22:55:03 2013 +0800 +++ b/common-kex.c Mon Oct 21 22:57:21 2013 +0800 @@ -34,10 +34,11 @@ #include "bignum.h" #include "random.h" #include "runopts.h" +#include "ecc.h" +#include "crypto_desc.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 +52,7 @@ 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, @@ -87,8 +87,9 @@ #endif static void read_kex_algos(); /* helper function for gen_new_keys */ -static void hashkeys(unsigned char *out, int outlen, - const hash_state * hs, unsigned const char X); +static void hashkeys(unsigned char *out, unsigned int outlen, + const hash_state * hs, const unsigned char X); +static void finish_kexhashbuf(void); /* Send our list of algorithms we can use */ @@ -150,7 +151,7 @@ ses.newkeys = (struct key_context*)m_malloc(sizeof(struct key_context)); if (ses.send_kex_first_guess) { - ses.newkeys->algo_kex = sshkex[0].val; + ses.newkeys->algo_kex = sshkex[0].data; ses.newkeys->algo_hostkey = sshhostkey[0].val; ses.send_kex_first_guess(); } @@ -279,26 +280,28 @@ * out must have at least min(SHA1_HASH_SIZE, outlen) bytes allocated. * * See Section 7.2 of rfc4253 (ssh transport) for details */ -static void hashkeys(unsigned char *out, int outlen, +static void hashkeys(unsigned char *out, unsigned int outlen, const hash_state * hs, const unsigned char X) { + const struct ltc_hash_descriptor *hash_desc = ses.newkeys->algo_kex->hash_desc; hash_state hs2; - int offset; + unsigned int offset; + unsigned char tmpout[hash_desc->hashsize]; memcpy(&hs2, hs, sizeof(hash_state)); - sha1_process(&hs2, &X, 1); - sha1_process(&hs2, ses.session_id, SHA1_HASH_SIZE); - sha1_done(&hs2, out); - for (offset = SHA1_HASH_SIZE; + hash_desc->process(&hs2, &X, 1); + hash_desc->process(&hs2, ses.session_id->data, ses.session_id->len); + hash_desc->done(&hs2, tmpout); + memcpy(out, tmpout, MIN(hash_desc->hashsize, outlen)); + for (offset = hash_desc->hashsize; offset < outlen; - offset += SHA1_HASH_SIZE) + offset += hash_desc->hashsize) { /* need to extend */ - unsigned char k2[SHA1_HASH_SIZE]; memcpy(&hs2, hs, sizeof(hash_state)); - sha1_process(&hs2, out, offset); - sha1_done(&hs2, k2); - memcpy(&out[offset], k2, MIN(outlen - offset, SHA1_HASH_SIZE)); + hash_desc->process(&hs2, out, offset); + hash_desc->done(&hs2, tmpout); + memcpy(&out[offset], tmpout, MIN(outlen - offset, hash_desc->hashsize)); } } @@ -319,26 +322,26 @@ unsigned char *trans_IV, *trans_key, *recv_IV, *recv_key; hash_state hs; - unsigned int C2S_keysize, S2C_keysize; + const struct ltc_hash_descriptor *hash_desc = ses.newkeys->algo_kex->hash_desc; char mactransletter, macrecvletter; /* Client or server specific */ TRACE(("enter gen_new_keys")) /* the dh_K and hash are the start of all hashes, we make use of that */ - sha1_init(&hs); - sha1_process_mp(&hs, ses.dh_K); + hash_desc->init(&hs); + hash_process_mp(hash_desc, &hs, ses.dh_K); mp_clear(ses.dh_K); m_free(ses.dh_K); - sha1_process(&hs, ses.hash, SHA1_HASH_SIZE); - m_burn(ses.hash, SHA1_HASH_SIZE); + hash_desc->process(&hs, ses.hash->data, ses.hash->len); + buf_burn(ses.hash); + buf_free(ses.hash); + ses.hash = NULL; if (IS_DROPBEAR_CLIENT) { trans_IV = C2S_IV; recv_IV = S2C_IV; trans_key = C2S_key; recv_key = S2C_key; - C2S_keysize = ses.newkeys->trans.algo_crypt->keysize; - S2C_keysize = ses.newkeys->recv.algo_crypt->keysize; mactransletter = 'E'; macrecvletter = 'F'; } else { @@ -346,16 +349,14 @@ recv_IV = C2S_IV; trans_key = S2C_key; recv_key = C2S_key; - C2S_keysize = ses.newkeys->recv.algo_crypt->keysize; - S2C_keysize = ses.newkeys->trans.algo_crypt->keysize; mactransletter = 'F'; macrecvletter = 'E'; } - hashkeys(C2S_IV, SHA1_HASH_SIZE, &hs, 'A'); - hashkeys(S2C_IV, SHA1_HASH_SIZE, &hs, 'B'); - hashkeys(C2S_key, C2S_keysize, &hs, 'C'); - hashkeys(S2C_key, S2C_keysize, &hs, 'D'); + hashkeys(C2S_IV, sizeof(C2S_IV), &hs, 'A'); + hashkeys(S2C_IV, sizeof(S2C_IV), &hs, 'B'); + hashkeys(C2S_key, sizeof(C2S_key), &hs, 'C'); + hashkeys(S2C_key, sizeof(S2C_key), &hs, 'D'); if (ses.newkeys->recv.algo_crypt->cipherdesc != NULL) { int recv_cipher = find_cipher(ses.newkeys->recv.algo_crypt->cipherdesc->name); @@ -381,16 +382,16 @@ } } - if (ses.newkeys->trans.algo_mac->hashdesc != NULL) { + if (ses.newkeys->trans.algo_mac->hash_desc != NULL) { hashkeys(ses.newkeys->trans.mackey, ses.newkeys->trans.algo_mac->keysize, &hs, mactransletter); - ses.newkeys->trans.hash_index = find_hash(ses.newkeys->trans.algo_mac->hashdesc->name); + ses.newkeys->trans.hash_index = find_hash(ses.newkeys->trans.algo_mac->hash_desc->name); } - if (ses.newkeys->recv.algo_mac->hashdesc != NULL) { + if (ses.newkeys->recv.algo_mac->hash_desc != NULL) { hashkeys(ses.newkeys->recv.mackey, ses.newkeys->recv.algo_mac->keysize, &hs, macrecvletter); - ses.newkeys->recv.hash_index = find_hash(ses.newkeys->recv.algo_mac->hashdesc->name); + ses.newkeys->recv.hash_index = find_hash(ses.newkeys->recv.algo_mac->hash_desc->name); } /* Ready to switch over */ @@ -560,28 +561,23 @@ 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. * See the transport rfc 4253 section 8 for details */ /* dh_pub and dh_priv MUST be already initialised */ -void gen_kexdh_vals(mp_int *dh_pub, mp_int *dh_priv) { +struct kex_dh_param *gen_kexdh_param() { DEF_MP_INT(dh_p); DEF_MP_INT(dh_q); DEF_MP_INT(dh_g); TRACE(("enter gen_kexdh_vals")) - - m_mp_init_multi(&dh_g, &dh_p, &dh_q, NULL); + + struct kex_dh_param *param = m_malloc(sizeof(*param)); + m_mp_init_multi(¶m->pub, ¶m->priv, NULL); /* read the prime and generator*/ load_dh_p(&dh_p); @@ -592,33 +588,39 @@ /* calculate q = (p-1)/2 */ /* dh_priv is just a temp var here */ - if (mp_sub_d(&dh_p, 1, dh_priv) != MP_OKAY) { + if (mp_sub_d(&dh_p, 1, ¶m->priv) != MP_OKAY) { dropbear_exit("Diffie-Hellman error"); } - if (mp_div_2(dh_priv, &dh_q) != MP_OKAY) { + if (mp_div_2(¶m->priv, &dh_q) != MP_OKAY) { dropbear_exit("Diffie-Hellman error"); } /* Generate a private portion 0 < dh_priv < dh_q */ - gen_random_mpint(&dh_q, dh_priv); + gen_random_mpint(&dh_q, ¶m->priv); /* f = g^y mod p */ - if (mp_exptmod(&dh_g, dh_priv, &dh_p, dh_pub) != MP_OKAY) { + if (mp_exptmod(&dh_g, ¶m->priv, &dh_p, ¶m->pub) != MP_OKAY) { dropbear_exit("Diffie-Hellman error"); } mp_clear_multi(&dh_g, &dh_p, &dh_q, NULL); + return param; +} + +void free_kexdh_param(struct kex_dh_param *param) +{ + mp_clear_multi(¶m->pub, ¶m->priv, NULL); + m_free(param); } /* This function is fairly common between client/server, with some substitution * of dh_e/dh_f etc. Hence these arguments: * dh_pub_us is 'e' for the client, 'f' for the server. dh_pub_them is * vice-versa. dh_priv is the x/y value corresponding to dh_pub_us */ -void kexdh_comb_key(mp_int *dh_pub_us, mp_int *dh_priv, mp_int *dh_pub_them, +void kexdh_comb_key(struct kex_dh_param *param, mp_int *dh_pub_them, sign_key *hostkey) { mp_int dh_p; mp_int *dh_e = NULL, *dh_f = NULL; - hash_state hs; /* read the prime and generator*/ m_mp_init(&dh_p); @@ -631,9 +633,8 @@ } /* 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, dh_priv, &dh_p, ses.dh_K) != MP_OKAY) { + m_mp_alloc_init_multi(&ses.dh_K, NULL); + if (mp_exptmod(dh_pub_them, ¶m->priv, &dh_p, ses.dh_K) != MP_OKAY) { dropbear_exit("Diffie-Hellman error"); } @@ -643,11 +644,11 @@ /* 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 = dh_pub_us; + dh_e = ¶m->pub; dh_f = dh_pub_them; } else { dh_e = dh_pub_them; - dh_f = dh_pub_us; + dh_f = ¶m->pub; } /* Create the remainder of the hash buffer, to generate the exchange hash */ @@ -661,11 +662,70 @@ buf_putmpint(ses.kexhashbuf, ses.dh_K); /* calculate the hash H to sign */ - sha1_init(&hs); + finish_kexhashbuf(); +} + +#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, ses.newkeys->algo_kex->ecc_curve->dp) != 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 kexecdh_comb_key(struct kex_ecdh_param *param, buffer *pub_them, + sign_key *hostkey) { + const struct dropbear_kex *algo_kex = ses.newkeys->algo_kex; + // public keys from client and server + ecc_key *Q_C, *Q_S, *Q_them; + + Q_them = buf_get_ecc_raw_pubkey(pub_them, algo_kex->ecc_curve); + + 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 */ + if (IS_DROPBEAR_CLIENT) { + Q_C = ¶m->key; + Q_S = Q_them; + } else { + Q_C = Q_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 */ + buf_put_ecc_raw_pubkey_string(ses.kexhashbuf, Q_C); + /* Q_S, server's ephemeral public key octet string */ + buf_put_ecc_raw_pubkey_string(ses.kexhashbuf, Q_S); + /* K, the shared secret */ + buf_putmpint(ses.kexhashbuf, ses.dh_K); + + /* calculate the hash H to sign */ + finish_kexhashbuf(); +} +#endif + +static void finish_kexhashbuf(void) { + hash_state hs; + const struct ltc_hash_descriptor *hash_desc = ses.newkeys->algo_kex->hash_desc; + + hash_desc->init(&hs); buf_setpos(ses.kexhashbuf, 0); - sha1_process(&hs, buf_getptr(ses.kexhashbuf, ses.kexhashbuf->len), + hash_desc->process(&hs, buf_getptr(ses.kexhashbuf, ses.kexhashbuf->len), ses.kexhashbuf->len); - sha1_done(&hs, ses.hash); + ses.hash = buf_new(hash_desc->hashsize); + hash_desc->done(&hs, buf_getwriteptr(ses.hash, hash_desc->hashsize)); + buf_setlen(ses.hash, hash_desc->hashsize); buf_burn(ses.kexhashbuf); buf_free(ses.kexhashbuf); @@ -674,9 +734,9 @@ /* 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); + ses.session_id = buf_newcopy(ses.hash); } + } /* read the other side's algo list. buf_match_algo is a callback to match @@ -719,7 +779,7 @@ } TRACE(("kexguess2 %d", kexguess2)) TRACE(("kex algo %s", algo->name)) - ses.newkeys->algo_kex = algo->val; + ses.newkeys->algo_kex = algo->data; /* server_host_key_algorithms */ algo = buf_match_algo(ses.payload, sshhostkey, &kexguess2, &goodguess);