| /* |
| * Dropbear - a SSH2 server |
| * |
| * Copyright (c) 2002,2003 Matt Johnston |
| * Copyright (c) 2004 by Mihnea Stoenescu |
| * All rights reserved. |
| * |
| * Permission is hereby granted, free of charge, to any person obtaining a copy |
| * of this software and associated documentation files (the "Software"), to deal |
| * in the Software without restriction, including without limitation the rights |
| * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell |
| * copies of the Software, and to permit persons to whom the Software is |
| * furnished to do so, subject to the following conditions: |
| * |
| * The above copyright notice and this permission notice shall be included in |
| * all copies or substantial portions of the Software. |
| * |
| * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR |
| * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, |
| * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE |
| * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER |
| * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, |
| * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
| * SOFTWARE. */ |
| |
| #include "includes.h" |
| #include "dbutil.h" |
| #include "algo.h" |
| #include "buffer.h" |
| #include "session.h" |
| #include "kex.h" |
| #include "ssh.h" |
| #include "packet.h" |
| #include "bignum.h" |
| #include "random.h" |
| #include "runopts.h" |
| |
| |
| static void send_msg_kexdh_reply(mp_int *dh_e); |
| |
| /* Handle a diffie-hellman key exchange initialisation. This involves |
| * calculating a session key reply value, and corresponding hash. These |
| * are carried out by send_msg_kexdh_reply(). recv_msg_kexdh_init() calls |
| * that function, then brings the new keys into use */ |
| void recv_msg_kexdh_init() { |
| |
| DEF_MP_INT(dh_e); |
| |
| TRACE(("enter recv_msg_kexdh_init")) |
| if (!ses.kexstate.recvkexinit) { |
| dropbear_exit("Premature kexdh_init message received"); |
| } |
| |
| m_mp_init(&dh_e); |
| buf_getmpint(ses.payload, &dh_e); |
| |
| send_msg_kexdh_reply(&dh_e); |
| |
| mp_clear(&dh_e); |
| |
| send_msg_newkeys(); |
| ses.requirenext = SSH_MSG_NEWKEYS; |
| TRACE(("leave recv_msg_kexdh_init")) |
| } |
| |
| /* Generate our side of the diffie-hellman key exchange value (dh_f), and |
| * calculate the session key using the diffie-hellman algorithm. Following |
| * that, the session hash is calculated, and signed with RSA or DSS. The |
| * result is sent to the client. |
| * |
| * See the ietf-secsh-transport draft, section 6, for details */ |
| static void send_msg_kexdh_reply(mp_int *dh_e) { |
| |
| DEF_MP_INT(dh_y); |
| DEF_MP_INT(dh_f); |
| |
| TRACE(("enter send_msg_kexdh_reply")) |
| m_mp_init_multi(&dh_y, &dh_f, NULL); |
| |
| gen_kexdh_vals(&dh_f, &dh_y); |
| |
| kexdh_comb_key(&dh_f, &dh_y, dh_e, svr_opts.hostkey); |
| mp_clear(&dh_y); |
| |
| /* we can start creating the kexdh_reply packet */ |
| CHECKCLEARTOWRITE(); |
| buf_putbyte(ses.writepayload, SSH_MSG_KEXDH_REPLY); |
| buf_put_pub_key(ses.writepayload, svr_opts.hostkey, |
| ses.newkeys->algo_hostkey); |
| |
| /* put f */ |
| buf_putmpint(ses.writepayload, &dh_f); |
| mp_clear(&dh_f); |
| |
| /* calc the signature */ |
| buf_put_sign(ses.writepayload, svr_opts.hostkey, |
| ses.newkeys->algo_hostkey, ses.hash, SHA1_HASH_SIZE); |
| |
| /* the SSH_MSG_KEXDH_REPLY is done */ |
| encrypt_packet(); |
| |
| TRACE(("leave send_msg_kexdh_reply")) |
| } |
| |