diff options
Diffstat (limited to 'svr-kex.c')
| -rw-r--r-- | svr-kex.c | 148 |
1 files changed, 127 insertions, 21 deletions
@@ -35,6 +35,7 @@ #include "random.h" #include "runopts.h" #include "ecc.h" +#include "gensignkey.h" static void send_msg_kexdh_reply(mp_int *dh_e, buffer *ecdh_qs); @@ -52,15 +53,22 @@ void recv_msg_kexdh_init() { dropbear_exit("Premature kexdh_init message received"); } - if (IS_NORMAL_DH(ses.newkeys->algo_kex)) { - m_mp_init(&dh_e); - if (buf_getmpint(ses.payload, &dh_e) != DROPBEAR_SUCCESS) { - dropbear_exit("Failed to get kex value"); - } - } else { -#ifdef DROPBEAR_ECDH - ecdh_qs = buf_getstringbuf(ses.payload); + switch (ses.newkeys->algo_kex->mode) { + case DROPBEAR_KEX_NORMAL_DH: + m_mp_init(&dh_e); + if (buf_getmpint(ses.payload, &dh_e) != DROPBEAR_SUCCESS) { + dropbear_exit("Bad kex value"); + } + break; + case DROPBEAR_KEX_ECDH: + case DROPBEAR_KEX_CURVE25519: +#if defined(DROPBEAR_ECDH) || defined(DROPBEAR_CURVE25519) + ecdh_qs = buf_getstringbuf(ses.payload); #endif + break; + } + if (ses.payload->pos != ses.payload->len) { + dropbear_exit("Bad kex value"); } send_msg_kexdh_reply(&dh_e, ecdh_qs); @@ -68,6 +76,7 @@ void recv_msg_kexdh_init() { mp_clear(&dh_e); if (ecdh_qs) { buf_free(ecdh_qs); + ecdh_qs = NULL; } send_msg_newkeys(); @@ -75,6 +84,79 @@ void recv_msg_kexdh_init() { ses.requirenext[1] = 0; TRACE(("leave recv_msg_kexdh_init")) } + +#ifdef DROPBEAR_DELAY_HOSTKEY +static void svr_ensure_hostkey() { + + const char* fn = NULL; + char *fn_temp = NULL; + enum signkey_type type = ses.newkeys->algo_hostkey; + void **hostkey = signkey_key_ptr(svr_opts.hostkey, type); + int ret = DROPBEAR_FAILURE; + + if (hostkey && *hostkey) { + return; + } + + switch (type) + { +#ifdef DROPBEAR_RSA + case DROPBEAR_SIGNKEY_RSA: + fn = RSA_PRIV_FILENAME; + break; +#endif +#ifdef DROPBEAR_DSS + case DROPBEAR_SIGNKEY_DSS: + fn = DSS_PRIV_FILENAME; + break; +#endif +#ifdef DROPBEAR_ECDSA + case DROPBEAR_SIGNKEY_ECDSA_NISTP256: + case DROPBEAR_SIGNKEY_ECDSA_NISTP384: + case DROPBEAR_SIGNKEY_ECDSA_NISTP521: + fn = ECDSA_PRIV_FILENAME; + break; +#endif + default: + (void)0; + } + + if (readhostkey(fn, svr_opts.hostkey, &type) == DROPBEAR_SUCCESS) { + return; + } + + fn_temp = m_malloc(strlen(fn) + 20); + snprintf(fn_temp, strlen(fn)+20, "%s.tmp%d", fn, getpid()); + + if (signkey_generate(type, 0, fn_temp) == DROPBEAR_FAILURE) { + goto out; + } + + if (link(fn_temp, fn) < 0) { + /* It's OK to get EEXIST - we probably just lost a race + with another connection to generate the key */ + if (errno != EEXIST) { + dropbear_log(LOG_ERR, "Failed moving key file to %s: %s", fn, + strerror(errno)); + /* XXX fallback to non-atomic copy for some filesystems? */ + goto out; + } + } + + ret = readhostkey(fn, svr_opts.hostkey, &type); + +out: + if (fn_temp) { + unlink(fn_temp); + m_free(fn_temp); + } + + if (ret == DROPBEAR_FAILURE) + { + dropbear_exit("Couldn't read or generate hostkey %s", fn); + } +} +#endif /* Generate our side of the diffie-hellman key exchange value (dh_f), and * calculate the session key using the diffie-hellman algorithm. Following @@ -88,26 +170,50 @@ static void send_msg_kexdh_reply(mp_int *dh_e, buffer *ecdh_qs) { /* we can start creating the kexdh_reply packet */ CHECKCLEARTOWRITE(); + +#ifdef DROPBEAR_DELAY_HOSTKEY + if (svr_opts.delay_hostkey) + { + svr_ensure_hostkey(); + } +#endif + buf_putbyte(ses.writepayload, SSH_MSG_KEXDH_REPLY); buf_put_pub_key(ses.writepayload, svr_opts.hostkey, ses.newkeys->algo_hostkey); - if (IS_NORMAL_DH(ses.newkeys->algo_kex)) { - // Normal diffie-hellman - struct kex_dh_param * dh_param = gen_kexdh_param(); - kexdh_comb_key(dh_param, dh_e, svr_opts.hostkey); - - /* put f */ - buf_putmpint(ses.writepayload, &dh_param->pub); - free_kexdh_param(dh_param); - } else { + switch (ses.newkeys->algo_kex->mode) { + case DROPBEAR_KEX_NORMAL_DH: + { + struct kex_dh_param * dh_param = gen_kexdh_param(); + kexdh_comb_key(dh_param, dh_e, svr_opts.hostkey); + + /* put f */ + buf_putmpint(ses.writepayload, &dh_param->pub); + free_kexdh_param(dh_param); + } + break; + case DROPBEAR_KEX_ECDH: #ifdef DROPBEAR_ECDH - struct kex_ecdh_param *ecdh_param = gen_kexecdh_param(); - kexecdh_comb_key(ecdh_param, ecdh_qs, svr_opts.hostkey); + { + struct kex_ecdh_param *ecdh_param = gen_kexecdh_param(); + kexecdh_comb_key(ecdh_param, ecdh_qs, svr_opts.hostkey); - buf_put_ecc_raw_pubkey_string(ses.writepayload, &ecdh_param->key); - free_kexecdh_param(ecdh_param); + buf_put_ecc_raw_pubkey_string(ses.writepayload, &ecdh_param->key); + free_kexecdh_param(ecdh_param); + } +#endif + break; + case DROPBEAR_KEX_CURVE25519: +#ifdef DROPBEAR_CURVE25519 + { + struct kex_curve25519_param *param = gen_kexcurve25519_param(); + kexcurve25519_comb_key(param, ecdh_qs, svr_opts.hostkey); + buf_putstring(ses.writepayload, param->pub, CURVE25519_LEN); + free_kexcurve25519_param(param); + } #endif + break; } /* calc the signature */ |