/*

 * dh.c - Diffie-Helman algorithm code against SSH 2

 *

 * This file is part of the SSH Library

 *

 * Copyright (c) 2003-2018 by Aris Adamantiadis

 * Copyright (c) 2009-2013 by Andreas Schneider <asn@cryptomilk.org>

 * Copyright (c) 2012      by Dmitriy Kuznetsov <dk@yandex.ru>

 *

 * The SSH Library is free software; you can redistribute it and/or modify

 * it under the terms of the GNU Lesser General Public License as published by

 * the Free Software Foundation; either version 2.1 of the License, or (at your

 * option) any later version.

 *

 * The SSH Library is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public

 * License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public License

 * along with the SSH Library; see the file COPYING.  If not, write to

 * the Free Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,

 * MA 02111-1307, USA.

 */

#include "config.h"

#include "libssh/priv.h"

#include "libssh/crypto.h"

#include "libssh/buffer.h"

#include "libssh/session.h"

#include "libssh/misc.h"

#include "libssh/dh.h"

#include "libssh/ssh2.h"

#include "libssh/pki.h"

#include "libssh/bignum.h"

static unsigned char p_group1_value[] = {

        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,

        0x3B, 0x13, 0x9B, 0x22, 0x51, 0x4A, 0x08, 0x79, 0x8E, 0x34, 0x04, 0xDD,

        0xEF, 0x95, 0x19, 0xB3, 0xCD, 0x3A, 0x43, 0x1B, 0x30, 0x2B, 0x0A, 0x6D,

        0xF2, 0x5F, 0x14, 0x37, 0x4F, 0xE1, 0x35, 0x6D, 0x6D, 0x51, 0xC2, 0x45,

        0xE4, 0x85, 0xB5, 0x76, 0x62, 0x5E, 0x7E, 0xC6, 0xF4, 0x4C, 0x42, 0xE9,

        0xA6, 0x37, 0xED, 0x6B, 0x0B, 0xFF, 0x5C, 0xB6, 0xF4, 0x06, 0xB7, 0xED,

        0xEE, 0x38, 0x6B, 0xFB, 0x5A, 0x89, 0x9F, 0xA5, 0xAE, 0x9F, 0x24, 0x11,

        0x7C, 0x4B, 0x1F, 0xE6, 0x49, 0x28, 0x66, 0x51, 0xEC, 0xE6, 0x53, 0x81,

        0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};

#define P_GROUP1_LEN 128	/* Size in bytes of the p number */

static unsigned char p_group14_value[] = {

        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,

        0x3B, 0x13, 0x9B, 0x22, 0x51, 0x4A, 0x08, 0x79, 0x8E, 0x34, 0x04, 0xDD,

        0xEF, 0x95, 0x19, 0xB3, 0xCD, 0x3A, 0x43, 0x1B, 0x30, 0x2B, 0x0A, 0x6D,

        0xF2, 0x5F, 0x14, 0x37, 0x4F, 0xE1, 0x35, 0x6D, 0x6D, 0x51, 0xC2, 0x45,

        0xE4, 0x85, 0xB5, 0x76, 0x62, 0x5E, 0x7E, 0xC6, 0xF4, 0x4C, 0x42, 0xE9,

        0xA6, 0x37, 0xED, 0x6B, 0x0B, 0xFF, 0x5C, 0xB6, 0xF4, 0x06, 0xB7, 0xED,

        0xEE, 0x38, 0x6B, 0xFB, 0x5A, 0x89, 0x9F, 0xA5, 0xAE, 0x9F, 0x24, 0x11,

        0x7C, 0x4B, 0x1F, 0xE6, 0x49, 0x28, 0x66, 0x51, 0xEC, 0xE4, 0x5B, 0x3D,

        0xC2, 0x00, 0x7C, 0xB8, 0xA1, 0x63, 0xBF, 0x05, 0x98, 0xDA, 0x48, 0x36,

        0x1C, 0x55, 0xD3, 0x9A, 0x69, 0x16, 0x3F, 0xA8, 0xFD, 0x24, 0xCF, 0x5F,

        0x83, 0x65, 0x5D, 0x23, 0xDC, 0xA3, 0xAD, 0x96, 0x1C, 0x62, 0xF3, 0x56,

        0x20, 0x85, 0x52, 0xBB, 0x9E, 0xD5, 0x29, 0x07, 0x70, 0x96, 0x96, 0x6D,

        0x67, 0x0C, 0x35, 0x4E, 0x4A, 0xBC, 0x98, 0x04, 0xF1, 0x74, 0x6C, 0x08,

        0xCA, 0x18, 0x21, 0x7C, 0x32, 0x90, 0x5E, 0x46, 0x2E, 0x36, 0xCE, 0x3B,

        0xE3, 0x9E, 0x77, 0x2C, 0x18, 0x0E, 0x86, 0x03, 0x9B, 0x27, 0x83, 0xA2,

        0xEC, 0x07, 0xA2, 0x8F, 0xB5, 0xC5, 0x5D, 0xF0, 0x6F, 0x4C, 0x52, 0xC9,

        0xDE, 0x2B, 0xCB, 0xF6, 0x95, 0x58, 0x17, 0x18, 0x39, 0x95, 0x49, 0x7C,

        0xEA, 0x95, 0x6A, 0xE5, 0x15, 0xD2, 0x26, 0x18, 0x98, 0xFA, 0x05, 0x10,

        0x15, 0x72, 0x8E, 0x5A, 0x8A, 0xAC, 0xAA, 0x68, 0xFF, 0xFF, 0xFF, 0xFF,

        0xFF, 0xFF, 0xFF, 0xFF};

#define P_GROUP14_LEN 256 /* Size in bytes of the p number for group 14 */

static unsigned char p_group16_value[] = {

    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,

    0x3B, 0x13, 0x9B, 0x22, 0x51, 0x4A, 0x08, 0x79, 0x8E, 0x34, 0x04, 0xDD,

    0xEF, 0x95, 0x19, 0xB3, 0xCD, 0x3A, 0x43, 0x1B, 0x30, 0x2B, 0x0A, 0x6D,

    0xF2, 0x5F, 0x14, 0x37, 0x4F, 0xE1, 0x35, 0x6D, 0x6D, 0x51, 0xC2, 0x45,

    0xE4, 0x85, 0xB5, 0x76, 0x62, 0x5E, 0x7E, 0xC6, 0xF4, 0x4C, 0x42, 0xE9,

    0xA6, 0x37, 0xED, 0x6B, 0x0B, 0xFF, 0x5C, 0xB6, 0xF4, 0x06, 0xB7, 0xED,

    0xEE, 0x38, 0x6B, 0xFB, 0x5A, 0x89, 0x9F, 0xA5, 0xAE, 0x9F, 0x24, 0x11,

    0x7C, 0x4B, 0x1F, 0xE6, 0x49, 0x28, 0x66, 0x51, 0xEC, 0xE4, 0x5B, 0x3D,

    0xC2, 0x00, 0x7C, 0xB8, 0xA1, 0x63, 0xBF, 0x05, 0x98, 0xDA, 0x48, 0x36,

    0x1C, 0x55, 0xD3, 0x9A, 0x69, 0x16, 0x3F, 0xA8, 0xFD, 0x24, 0xCF, 0x5F,

    0x83, 0x65, 0x5D, 0x23, 0xDC, 0xA3, 0xAD, 0x96, 0x1C, 0x62, 0xF3, 0x56,

    0x20, 0x85, 0x52, 0xBB, 0x9E, 0xD5, 0x29, 0x07, 0x70, 0x96, 0x96, 0x6D,

    0x67, 0x0C, 0x35, 0x4E, 0x4A, 0xBC, 0x98, 0x04, 0xF1, 0x74, 0x6C, 0x08,

    0xCA, 0x18, 0x21, 0x7C, 0x32, 0x90, 0x5E, 0x46, 0x2E, 0x36, 0xCE, 0x3B,

    0xE3, 0x9E, 0x77, 0x2C, 0x18, 0x0E, 0x86, 0x03, 0x9B, 0x27, 0x83, 0xA2,

    0xEC, 0x07, 0xA2, 0x8F, 0xB5, 0xC5, 0x5D, 0xF0, 0x6F, 0x4C, 0x52, 0xC9,

    0xDE, 0x2B, 0xCB, 0xF6, 0x95, 0x58, 0x17, 0x18, 0x39, 0x95, 0x49, 0x7C,

    0xEA, 0x95, 0x6A, 0xE5, 0x15, 0xD2, 0x26, 0x18, 0x98, 0xFA, 0x05, 0x10,

    0x15, 0x72, 0x8E, 0x5A, 0x8A, 0xAA, 0xC4, 0x2D, 0xAD, 0x33, 0x17, 0x0D,

    0x04, 0x50, 0x7A, 0x33, 0xA8, 0x55, 0x21, 0xAB, 0xDF, 0x1C, 0xBA, 0x64,

    0xEC, 0xFB, 0x85, 0x04, 0x58, 0xDB, 0xEF, 0x0A, 0x8A, 0xEA, 0x71, 0x57,

    0x5D, 0x06, 0x0C, 0x7D, 0xB3, 0x97, 0x0F, 0x85, 0xA6, 0xE1, 0xE4, 0xC7,

    0xAB, 0xF5, 0xAE, 0x8C, 0xDB, 0x09, 0x33, 0xD7, 0x1E, 0x8C, 0x94, 0xE0,

    0x4A, 0x25, 0x61, 0x9D, 0xCE, 0xE3, 0xD2, 0x26, 0x1A, 0xD2, 0xEE, 0x6B,

    0xF1, 0x2F, 0xFA, 0x06, 0xD9, 0x8A, 0x08, 0x64, 0xD8, 0x76, 0x02, 0x73,

    0x3E, 0xC8, 0x6A, 0x64, 0x52, 0x1F, 0x2B, 0x18, 0x17, 0x7B, 0x20, 0x0C,

    0xBB, 0xE1, 0x17, 0x57, 0x7A, 0x61, 0x5D, 0x6C, 0x77, 0x09, 0x88, 0xC0,

    0xBA, 0xD9, 0x46, 0xE2, 0x08, 0xE2, 0x4F, 0xA0, 0x74, 0xE5, 0xAB, 0x31,

    0x43, 0xDB, 0x5B, 0xFC, 0xE0, 0xFD, 0x10, 0x8E, 0x4B, 0x82, 0xD1, 0x20,

    0xA9, 0x21, 0x08, 0x01, 0x1A, 0x72, 0x3C, 0x12, 0xA7, 0x87, 0xE6, 0xD7,

    0x88, 0x71, 0x9A, 0x10, 0xBD, 0xBA, 0x5B, 0x26, 0x99, 0xC3, 0x27, 0x18,

    0x6A, 0xF4, 0xE2, 0x3C, 0x1A, 0x94, 0x68, 0x34, 0xB6, 0x15, 0x0B, 0xDA,

    0x25, 0x83, 0xE9, 0xCA, 0x2A, 0xD4, 0x4C, 0xE8, 0xDB, 0xBB, 0xC2, 0xDB,

    0x04, 0xDE, 0x8E, 0xF9, 0x2E, 0x8E, 0xFC, 0x14, 0x1F, 0xBE, 0xCA, 0xA6,

    0x28, 0x7C, 0x59, 0x47, 0x4E, 0x6B, 0xC0, 0x5D, 0x99, 0xB2, 0x96, 0x4F,

    0xA0, 0x90, 0xC3, 0xA2, 0x23, 0x3B, 0xA1, 0x86, 0x51, 0x5B, 0xE7, 0xED,

    0x1F, 0x61, 0x29, 0x70, 0xCE, 0xE2, 0xD7, 0xAF, 0xB8, 0x1B, 0xDD, 0x76,

    0x21, 0x70, 0x48, 0x1C, 0xD0, 0x06, 0x91, 0x27, 0xD5, 0xB0, 0x5A, 0xA9,

    0x93, 0xB4, 0xEA, 0x98, 0x8D, 0x8F, 0xDD, 0xC1, 0x86, 0xFF, 0xB7, 0xDC,

    0x90, 0xA6, 0xC0, 0x8F, 0x4D, 0xF4, 0x35, 0xC9, 0x34, 0x06, 0x31, 0x99,

    0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF};

#define P_GROUP16_LEN 512 /* Size in bytes of the p number for group 16 */

static unsigned char p_group18_value[] = {

    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,

    0x3B, 0x13, 0x9B, 0x22, 0x51, 0x4A, 0x08, 0x79, 0x8E, 0x34, 0x04, 0xDD,

    0xEF, 0x95, 0x19, 0xB3, 0xCD, 0x3A, 0x43, 0x1B, 0x30, 0x2B, 0x0A, 0x6D,

    0xF2, 0x5F, 0x14, 0x37, 0x4F, 0xE1, 0x35, 0x6D, 0x6D, 0x51, 0xC2, 0x45,

    0xE4, 0x85, 0xB5, 0x76, 0x62, 0x5E, 0x7E, 0xC6, 0xF4, 0x4C, 0x42, 0xE9,

    0xA6, 0x37, 0xED, 0x6B, 0x0B, 0xFF, 0x5C, 0xB6, 0xF4, 0x06, 0xB7, 0xED,

    0xEE, 0x38, 0x6B, 0xFB, 0x5A, 0x89, 0x9F, 0xA5, 0xAE, 0x9F, 0x24, 0x11,

    0x7C, 0x4B, 0x1F, 0xE6, 0x49, 0x28, 0x66, 0x51, 0xEC, 0xE4, 0x5B, 0x3D,

    0xC2, 0x00, 0x7C, 0xB8, 0xA1, 0x63, 0xBF, 0x05, 0x98, 0xDA, 0x48, 0x36,

    0x1C, 0x55, 0xD3, 0x9A, 0x69, 0x16, 0x3F, 0xA8, 0xFD, 0x24, 0xCF, 0x5F,

    0x83, 0x65, 0x5D, 0x23, 0xDC, 0xA3, 0xAD, 0x96, 0x1C, 0x62, 0xF3, 0x56,

    0x20, 0x85, 0x52, 0xBB, 0x9E, 0xD5, 0x29, 0x07, 0x70, 0x96, 0x96, 0x6D,

    0x67, 0x0C, 0x35, 0x4E, 0x4A, 0xBC, 0x98, 0x04, 0xF1, 0x74, 0x6C, 0x08,

    0xCA, 0x18, 0x21, 0x7C, 0x32, 0x90, 0x5E, 0x46, 0x2E, 0x36, 0xCE, 0x3B,

    0xE3, 0x9E, 0x77, 0x2C, 0x18, 0x0E, 0x86, 0x03, 0x9B, 0x27, 0x83, 0xA2,

    0xEC, 0x07, 0xA2, 0x8F, 0xB5, 0xC5, 0x5D, 0xF0, 0x6F, 0x4C, 0x52, 0xC9,

    0xDE, 0x2B, 0xCB, 0xF6, 0x95, 0x58, 0x17, 0x18, 0x39, 0x95, 0x49, 0x7C,

    0xEA, 0x95, 0x6A, 0xE5, 0x15, 0xD2, 0x26, 0x18, 0x98, 0xFA, 0x05, 0x10,

    0x15, 0x72, 0x8E, 0x5A, 0x8A, 0xAA, 0xC4, 0x2D, 0xAD, 0x33, 0x17, 0x0D,

    0x04, 0x50, 0x7A, 0x33, 0xA8, 0x55, 0x21, 0xAB, 0xDF, 0x1C, 0xBA, 0x64,

    0xEC, 0xFB, 0x85, 0x04, 0x58, 0xDB, 0xEF, 0x0A, 0x8A, 0xEA, 0x71, 0x57,

    0x5D, 0x06, 0x0C, 0x7D, 0xB3, 0x97, 0x0F, 0x85, 0xA6, 0xE1, 0xE4, 0xC7,

    0xAB, 0xF5, 0xAE, 0x8C, 0xDB, 0x09, 0x33, 0xD7, 0x1E, 0x8C, 0x94, 0xE0,

    0x4A, 0x25, 0x61, 0x9D, 0xCE, 0xE3, 0xD2, 0x26, 0x1A, 0xD2, 0xEE, 0x6B,

    0xF1, 0x2F, 0xFA, 0x06, 0xD9, 0x8A, 0x08, 0x64, 0xD8, 0x76, 0x02, 0x73,

    0x3E, 0xC8, 0x6A, 0x64, 0x52, 0x1F, 0x2B, 0x18, 0x17, 0x7B, 0x20, 0x0C,

    0xBB, 0xE1, 0x17, 0x57, 0x7A, 0x61, 0x5D, 0x6C, 0x77, 0x09, 0x88, 0xC0,

    0xBA, 0xD9, 0x46, 0xE2, 0x08, 0xE2, 0x4F, 0xA0, 0x74, 0xE5, 0xAB, 0x31,

    0x43, 0xDB, 0x5B, 0xFC, 0xE0, 0xFD, 0x10, 0x8E, 0x4B, 0x82, 0xD1, 0x20,

    0xA9, 0x21, 0x08, 0x01, 0x1A, 0x72, 0x3C, 0x12, 0xA7, 0x87, 0xE6, 0xD7,

    0x88, 0x71, 0x9A, 0x10, 0xBD, 0xBA, 0x5B, 0x26, 0x99, 0xC3, 0x27, 0x18,

    0x6A, 0xF4, 0xE2, 0x3C, 0x1A, 0x94, 0x68, 0x34, 0xB6, 0x15, 0x0B, 0xDA,

    0x25, 0x83, 0xE9, 0xCA, 0x2A, 0xD4, 0x4C, 0xE8, 0xDB, 0xBB, 0xC2, 0xDB,

    0x04, 0xDE, 0x8E, 0xF9, 0x2E, 0x8E, 0xFC, 0x14, 0x1F, 0xBE, 0xCA, 0xA6,

    0x28, 0x7C, 0x59, 0x47, 0x4E, 0x6B, 0xC0, 0x5D, 0x99, 0xB2, 0x96, 0x4F,

    0xA0, 0x90, 0xC3, 0xA2, 0x23, 0x3B, 0xA1, 0x86, 0x51, 0x5B, 0xE7, 0xED,

    0x1F, 0x61, 0x29, 0x70, 0xCE, 0xE2, 0xD7, 0xAF, 0xB8, 0x1B, 0xDD, 0x76,

    0x21, 0x70, 0x48, 0x1C, 0xD0, 0x06, 0x91, 0x27, 0xD5, 0xB0, 0x5A, 0xA9,

    0x93, 0xB4, 0xEA, 0x98, 0x8D, 0x8F, 0xDD, 0xC1, 0x86, 0xFF, 0xB7, 0xDC,

    0x90, 0xA6, 0xC0, 0x8F, 0x4D, 0xF4, 0x35, 0xC9, 0x34, 0x02, 0x84, 0x92,

    0x36, 0xC3, 0xFA, 0xB4, 0xD2, 0x7C, 0x70, 0x26, 0xC1, 0xD4, 0xDC, 0xB2,

    0x60, 0x26, 0x46, 0xDE, 0xC9, 0x75, 0x1E, 0x76, 0x3D, 0xBA, 0x37, 0xBD,

    0xF8, 0xFF, 0x94, 0x06, 0xAD, 0x9E, 0x53, 0x0E, 0xE5, 0xDB, 0x38, 0x2F,

    0x41, 0x30, 0x01, 0xAE, 0xB0, 0x6A, 0x53, 0xED, 0x90, 0x27, 0xD8, 0x31,

    0x17, 0x97, 0x27, 0xB0, 0x86, 0x5A, 0x89, 0x18, 0xDA, 0x3E, 0xDB, 0xEB,

    0xCF, 0x9B, 0x14, 0xED, 0x44, 0xCE, 0x6C, 0xBA, 0xCE, 0xD4, 0xBB, 0x1B,

    0xDB, 0x7F, 0x14, 0x47, 0xE6, 0xCC, 0x25, 0x4B, 0x33, 0x20, 0x51, 0x51,

    0x2B, 0xD7, 0xAF, 0x42, 0x6F, 0xB8, 0xF4, 0x01, 0x37, 0x8C, 0xD2, 0xBF,

    0x59, 0x83, 0xCA, 0x01, 0xC6, 0x4B, 0x92, 0xEC, 0xF0, 0x32, 0xEA, 0x15,

    0xD1, 0x72, 0x1D, 0x03, 0xF4, 0x82, 0xD7, 0xCE, 0x6E, 0x74, 0xFE, 0xF6,

    0xD5, 0x5E, 0x70, 0x2F, 0x46, 0x98, 0x0C, 0x82, 0xB5, 0xA8, 0x40, 0x31,

    0x90, 0x0B, 0x1C, 0x9E, 0x59, 0xE7, 0xC9, 0x7F, 0xBE, 0xC7, 0xE8, 0xF3,

    0x23, 0xA9, 0x7A, 0x7E, 0x36, 0xCC, 0x88, 0xBE, 0x0F, 0x1D, 0x45, 0xB7,

    0xFF, 0x58, 0x5A, 0xC5, 0x4B, 0xD4, 0x07, 0xB2, 0x2B, 0x41, 0x54, 0xAA,

    0xCC, 0x8F, 0x6D, 0x7E, 0xBF, 0x48, 0xE1, 0xD8, 0x14, 0xCC, 0x5E, 0xD2,

    0x0F, 0x80, 0x37, 0xE0, 0xA7, 0x97, 0x15, 0xEE, 0xF2, 0x9B, 0xE3, 0x28,

    0x06, 0xA1, 0xD5, 0x8B, 0xB7, 0xC5, 0xDA, 0x76, 0xF5, 0x50, 0xAA, 0x3D,

    0x8A, 0x1F, 0xBF, 0xF0, 0xEB, 0x19, 0xCC, 0xB1, 0xA3, 0x13, 0xD5, 0x5C,

    0xDA, 0x56, 0xC9, 0xEC, 0x2E, 0xF2, 0x96, 0x32, 0x38, 0x7F, 0xE8, 0xD7,

    0x6E, 0x3C, 0x04, 0x68, 0x04, 0x3E, 0x8F, 0x66, 0x3F, 0x48, 0x60, 0xEE,

    0x12, 0xBF, 0x2D, 0x5B, 0x0B, 0x74, 0x74, 0xD6, 0xE6, 0x94, 0xF9, 0x1E,

    0x6D, 0xBE, 0x11, 0x59, 0x74, 0xA3, 0x92, 0x6F, 0x12, 0xFE, 0xE5, 0xE4,

    0x38, 0x77, 0x7C, 0xB6, 0xA9, 0x32, 0xDF, 0x8C, 0xD8, 0xBE, 0xC4, 0xD0,

    0x73, 0xB9, 0x31, 0xBA, 0x3B, 0xC8, 0x32, 0xB6, 0x8D, 0x9D, 0xD3, 0x00,

    0x74, 0x1F, 0xA7, 0xBF, 0x8A, 0xFC, 0x47, 0xED, 0x25, 0x76, 0xF6, 0x93,

    0x6B, 0xA4, 0x24, 0x66, 0x3A, 0xAB, 0x63, 0x9C, 0x5A, 0xE4, 0xF5, 0x68,

    0x34, 0x23, 0xB4, 0x74, 0x2B, 0xF1, 0xC9, 0x78, 0x23, 0x8F, 0x16, 0xCB,

    0xE3, 0x9D, 0x65, 0x2D, 0xE3, 0xFD, 0xB8, 0xBE, 0xFC, 0x84, 0x8A, 0xD9,

    0x22, 0x22, 0x2E, 0x04, 0xA4, 0x03, 0x7C, 0x07, 0x13, 0xEB, 0x57, 0xA8,

    0x1A, 0x23, 0xF0, 0xC7, 0x34, 0x73, 0xFC, 0x64, 0x6C, 0xEA, 0x30, 0x6B,

    0x4B, 0xCB, 0xC8, 0x86, 0x2F, 0x83, 0x85, 0xDD, 0xFA, 0x9D, 0x4B, 0x7F,

    0xA2, 0xC0, 0x87, 0xE8, 0x79, 0x68, 0x33, 0x03, 0xED, 0x5B, 0xDD, 0x3A,

    0x06, 0x2B, 0x3C, 0xF5, 0xB3, 0xA2, 0x78, 0xA6, 0x6D, 0x2A, 0x13, 0xF8,

    0x3F, 0x44, 0xF8, 0x2D, 0xDF, 0x31, 0x0E, 0xE0, 0x74, 0xAB, 0x6A, 0x36,

    0x45, 0x97, 0xE8, 0x99, 0xA0, 0x25, 0x5D, 0xC1, 0x64, 0xF3, 0x1C, 0xC5,

    0x08, 0x46, 0x85, 0x1D, 0xF9, 0xAB, 0x48, 0x19, 0x5D, 0xED, 0x7E, 0xA1,

    0xB1, 0xD5, 0x10, 0xBD, 0x7E, 0xE7, 0x4D, 0x73, 0xFA, 0xF3, 0x6B, 0xC3,

    0x1E, 0xCF, 0xA2, 0x68, 0x35, 0x90, 0x46, 0xF4, 0xEB, 0x87, 0x9F, 0x92,

    0x40, 0x09, 0x43, 0x8B, 0x48, 0x1C, 0x6C, 0xD7, 0x88, 0x9A, 0x00, 0x2E,

    0xD5, 0xEE, 0x38, 0x2B, 0xC9, 0x19, 0x0D, 0xA6, 0xFC, 0x02, 0x6E, 0x47,

    0x95, 0x58, 0xE4, 0x47, 0x56, 0x77, 0xE9, 0xAA, 0x9E, 0x30, 0x50, 0xE2,

    0x76, 0x56, 0x94, 0xDF, 0xC8, 0x1F, 0x56, 0xE8, 0x80, 0xB9, 0x6E, 0x71,

    0x60, 0xC9, 0x80, 0xDD, 0x98, 0xED, 0xD3, 0xDF, 0xFF, 0xFF, 0xFF, 0xFF,

    0xFF, 0xFF, 0xFF, 0xFF};

#define P_GROUP18_LEN 1024 /* Size in bytes of the p number for group 18 */

bignum ssh_dh_generator;

bignum ssh_dh_group1;

bignum ssh_dh_group14;

bignum ssh_dh_group16;

bignum ssh_dh_group18;

static int dh_crypto_initialized;

/**

 * @internal

 * @brief Initialize global constants used in DH key agreement

 * @return SSH_OK on success, SSH_ERROR otherwise.

 */

int ssh_dh_init(void)

{

    unsigned long g_int = 2 ;	/* G is defined as 2 by the ssh2 standards */

    int rc;

    if (dh_crypto_initialized) {

        return SSH_OK;

    }

    dh_crypto_initialized = 1;

    ssh_dh_generator = bignum_new();

    if (ssh_dh_generator == NULL) {

        goto error;

    }

    rc = bignum_set_word(ssh_dh_generator, g_int);

    if (rc != 1) {

        goto error;

    }

    bignum_bin2bn(p_group1_value, P_GROUP1_LEN, &ssh_dh_group1);

    if (ssh_dh_group1 == NULL) {

        goto error;

    }

    bignum_bin2bn(p_group14_value, P_GROUP14_LEN, &ssh_dh_group14);

    if (ssh_dh_group14 == NULL) {

        goto error;

    }

    bignum_bin2bn(p_group16_value, P_GROUP16_LEN, &ssh_dh_group16);

    if (ssh_dh_group16 == NULL) {

        goto error;

    }

    bignum_bin2bn(p_group18_value, P_GROUP18_LEN, &ssh_dh_group18);

    if (ssh_dh_group18 == NULL) {

        goto error;

    }

    return 0;

error:

    ssh_dh_finalize();

    return SSH_ERROR;

}

/**

 * @internal

 * @brief Finalize and free global constants used in DH key agreement

 */

void ssh_dh_finalize(void)

{

    if (!dh_crypto_initialized) {

        return;

    }

    bignum_safe_free(ssh_dh_generator);

    bignum_safe_free(ssh_dh_group1);

    bignum_safe_free(ssh_dh_group14);

    bignum_safe_free(ssh_dh_group16);

    bignum_safe_free(ssh_dh_group18);

    dh_crypto_initialized = 0;

}

int ssh_dh_import_next_pubkey_blob(ssh_session session, ssh_string pubkey_blob)

{

    return ssh_pki_import_pubkey_blob(pubkey_blob,

                                      &session->next_crypto->server_pubkey);

}

static SSH_PACKET_CALLBACK(ssh_packet_client_dh_reply);

static ssh_packet_callback dh_client_callbacks[]= {

    ssh_packet_client_dh_reply

};

static struct ssh_packet_callbacks_struct ssh_dh_client_callbacks = {

    .start = SSH2_MSG_KEXDH_REPLY,

    .n_callbacks = 1,

    .callbacks = dh_client_callbacks,

    .user = NULL

};

/** @internal

 * @brief Starts diffie-hellman-group1 key exchange

 */

int ssh_client_dh_init(ssh_session session){

  struct ssh_crypto_struct *crypto = session->next_crypto;

  const_bignum pubkey;

  int rc;

  rc = ssh_dh_init_common(crypto);

  if (rc == SSH_ERROR) {

    goto error;

  }

  rc = ssh_dh_keypair_gen_keys(crypto->dh_ctx, DH_CLIENT_KEYPAIR);

  if (rc == SSH_ERROR){

      goto error;

  }

  rc = ssh_dh_keypair_get_keys(crypto->dh_ctx, DH_CLIENT_KEYPAIR,

                               NULL, &pubkey);

  if (rc != SSH_OK) {

    goto error;

  }

  rc = ssh_buffer_pack(session->out_buffer, "bB", SSH2_MSG_KEXDH_INIT, pubkey);

  if (rc != SSH_OK) {

    goto error;

  }

  /* register the packet callbacks */

  ssh_packet_set_callbacks(session, &ssh_dh_client_callbacks);

  session->dh_handshake_state = DH_STATE_INIT_SENT;

  rc = ssh_packet_send(session);

  return rc;

error:

  ssh_dh_cleanup(crypto);

  return SSH_ERROR;

}

SSH_PACKET_CALLBACK(ssh_packet_client_dh_reply){

  struct ssh_crypto_struct *crypto=session->next_crypto;

  ssh_string pubkey_blob = NULL;

  bignum server_pubkey;

  int rc;

  (void)type;

  (void)user;

  ssh_packet_remove_callbacks(session, &ssh_dh_client_callbacks);

  rc = ssh_buffer_unpack(packet, "SBS", &pubkey_blob, &server_pubkey,

          &crypto->dh_server_signature);

  if (rc == SSH_ERROR) {

      goto error;

  }

  rc = ssh_dh_keypair_set_keys(crypto->dh_ctx, DH_SERVER_KEYPAIR,

                               NULL, server_pubkey);

  if (rc != SSH_OK) {

      bignum_safe_free(server_pubkey);

      goto error;

  }

  rc = ssh_dh_import_next_pubkey_blob(session, pubkey_blob);

  SSH_STRING_FREE(pubkey_blob);

  if (rc != 0) {

      goto error;

  }

  rc = ssh_dh_compute_shared_secret(session->next_crypto->dh_ctx,

                                    DH_CLIENT_KEYPAIR, DH_SERVER_KEYPAIR,

                                    &session->next_crypto->shared_secret);

  ssh_dh_debug_crypto(session->next_crypto);

  if (rc == SSH_ERROR){

    ssh_set_error(session, SSH_FATAL, "Could not generate shared secret");

    goto error;

  }

  /* Send the MSG_NEWKEYS */

  if (ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS) < 0) {

    goto error;

  }

  rc=ssh_packet_send(session);

  if (rc == SSH_ERROR) {

    goto error;

  }

  SSH_LOG(SSH_LOG_PROTOCOL, "SSH_MSG_NEWKEYS sent");

  session->dh_handshake_state = DH_STATE_NEWKEYS_SENT;

  return SSH_PACKET_USED;

error:

  ssh_dh_cleanup(session->next_crypto);

  session->session_state=SSH_SESSION_STATE_ERROR;

  return SSH_PACKET_USED;

}

#ifdef WITH_SERVER

static SSH_PACKET_CALLBACK(ssh_packet_server_dh_init);

static ssh_packet_callback dh_server_callbacks[] = {

    ssh_packet_server_dh_init,

};

static struct ssh_packet_callbacks_struct ssh_dh_server_callbacks = {

    .start = SSH2_MSG_KEXDH_INIT,

    .n_callbacks = 1,

    .callbacks = dh_server_callbacks,

    .user = NULL

};

/** @internal

 * @brief sets up the diffie-hellman-groupx kex callbacks

 */

void ssh_server_dh_init(ssh_session session){

    /* register the packet callbacks */

    ssh_packet_set_callbacks(session, &ssh_dh_server_callbacks);

    ssh_dh_init_common(session->next_crypto);

}

/** @internal

 * @brief processes a SSH_MSG_KEXDH_INIT or SSH_MSG_KEX_DH_GEX_INIT packet and sends

 * the appropriate SSH_MSG_KEXDH_REPLY or SSH_MSG_KEX_DH_GEX_REPLY

 */

int ssh_server_dh_process_init(ssh_session session, ssh_buffer packet)

{

    struct ssh_crypto_struct *crypto = session->next_crypto;

    ssh_key privkey = NULL;

    enum ssh_digest_e digest = SSH_DIGEST_AUTO;

    ssh_string sig_blob = NULL;

    ssh_string pubkey_blob = NULL;

    bignum client_pubkey;

    const_bignum server_pubkey;

    int packet_type;

    int rc;

    rc = ssh_buffer_unpack(packet, "B", &client_pubkey);

    if (rc == SSH_ERROR) {

        ssh_set_error(session, SSH_FATAL, "No e number in client request");

        goto error;

    }

    rc = ssh_dh_keypair_set_keys(crypto->dh_ctx, DH_CLIENT_KEYPAIR,

                                 NULL, client_pubkey);

    if (rc != SSH_OK) {

        bignum_safe_free(client_pubkey);

        goto error;

    }

    rc = ssh_dh_keypair_gen_keys(crypto->dh_ctx, DH_SERVER_KEYPAIR);

    if (rc == SSH_ERROR) {

        goto error;

    }

    rc = ssh_get_key_params(session, &privkey, &digest);

    if (rc != SSH_OK) {

        goto error;

    }

    rc = ssh_dh_compute_shared_secret(crypto->dh_ctx,

                                      DH_SERVER_KEYPAIR, DH_CLIENT_KEYPAIR,

                                      &crypto->shared_secret);

    ssh_dh_debug_crypto(crypto);

    if (rc == SSH_ERROR) {

        ssh_set_error(session, SSH_FATAL, "Could not generate shared secret");

        goto error;

    }

    rc = ssh_make_sessionid(session);

    if (rc != SSH_OK) {

        ssh_set_error(session, SSH_FATAL, "Could not create a session id");

        goto error;

    }

    sig_blob = ssh_srv_pki_do_sign_sessionid(session, privkey, digest);

    if (sig_blob == NULL) {

        ssh_set_error(session, SSH_FATAL, "Could not sign the session id");

        goto error;

    }

    switch (crypto->kex_type){

    case SSH_KEX_DH_GROUP1_SHA1:

    case SSH_KEX_DH_GROUP14_SHA1:

    case SSH_KEX_DH_GROUP14_SHA256:

    case SSH_KEX_DH_GROUP16_SHA512:

    case SSH_KEX_DH_GROUP18_SHA512:

        packet_type = SSH2_MSG_KEXDH_REPLY;

        break;

#ifdef WITH_GEX

    case SSH_KEX_DH_GEX_SHA1:

    case SSH_KEX_DH_GEX_SHA256:

        packet_type = SSH2_MSG_KEX_DH_GEX_REPLY;

        break;

#endif /* WITH_GEX */

    default:

        ssh_set_error(session, SSH_FATAL, "Invalid kex type");

        goto error;

    }

    rc = ssh_dh_keypair_get_keys(crypto->dh_ctx, DH_SERVER_KEYPAIR,

                                 NULL, &server_pubkey);

    if (rc != SSH_OK){

        goto error;

    }

    rc = ssh_dh_get_next_server_publickey_blob(session, &pubkey_blob);

    if (rc != SSH_OK){

        ssh_set_error_oom(session);

        goto error;

    }

    rc = ssh_buffer_pack(session->out_buffer,

                         "bSBS",

                         packet_type,

                         pubkey_blob,

                         server_pubkey,

                         sig_blob);

    SSH_STRING_FREE(sig_blob);

    SSH_STRING_FREE(pubkey_blob);

    if(rc != SSH_OK) {

        ssh_set_error_oom(session);

        ssh_buffer_reinit(session->out_buffer);

        goto error;

    }

    rc = ssh_packet_send(session);

    if (rc == SSH_ERROR) {

        goto error;

    }

    SSH_LOG(SSH_LOG_DEBUG, "Sent KEX_DH_[GEX]_REPLY");

    if (ssh_buffer_add_u8(session->out_buffer, SSH2_MSG_NEWKEYS) < 0) {

        ssh_buffer_reinit(session->out_buffer);

        goto error;

    }

    session->dh_handshake_state=DH_STATE_NEWKEYS_SENT;

    if (ssh_packet_send(session) == SSH_ERROR) {

        goto error;

    }

    SSH_LOG(SSH_LOG_PACKET, "SSH_MSG_NEWKEYS sent");

    return SSH_OK;

error:

    SSH_STRING_FREE(sig_blob);

    SSH_STRING_FREE(pubkey_blob);

    session->session_state = SSH_SESSION_STATE_ERROR;

    ssh_dh_cleanup(session->next_crypto);

    return SSH_ERROR;

}

/** @internal

 * @brief parse an incoming SSH_MSG_KEXDH_INIT packet and complete

 *        Diffie-Hellman key exchange

 **/

static SSH_PACKET_CALLBACK(ssh_packet_server_dh_init){

    (void)type;

    (void)user;

    SSH_LOG(SSH_LOG_DEBUG, "Received SSH_MSG_KEXDH_INIT");

    ssh_packet_remove_callbacks(session, &ssh_dh_server_callbacks);

    ssh_server_dh_process_init(session, packet);

    return SSH_PACKET_USED;

}

/** @internal

 * @brief Choose a fallback group for the DH Group exchange if the

 * moduli file is not readable

 * @param[in] pmax maximum requestsd group size

 * @param[out] modulus

 * @param[out] generator

 * @returns SSH_OK on success, SSH_ERROR otherwise

 */

int ssh_fallback_group(uint32_t pmax,

                       bignum *modulus,

                       bignum *generator)

{

    *modulus = NULL;

    *generator = NULL;

    if (pmax < 3072) {

        bignum_dup(ssh_dh_group14, modulus);

    } else if (pmax < 6144) {

        bignum_dup(ssh_dh_group16, modulus);

    } else {

        bignum_dup(ssh_dh_group18, modulus);

    }

    if (*modulus == NULL) {

        return SSH_ERROR;

    }

    bignum_dup(ssh_dh_generator, generator);

    if (*generator == NULL) {

        bignum_safe_free((*modulus));

        return SSH_ERROR;

    }

    return SSH_OK;

}

#endif /* WITH_SERVER */

/**

 * @addtogroup libssh_session

 *

 * @{

 */

bool ssh_dh_is_known_group(bignum modulus, bignum generator)

{

    int cmp, bits;

    bignum m = NULL;

    bits = bignum_num_bits(modulus);

    if (bits < 3072) {

        m = ssh_dh_group14;

    } else if (bits < 6144) {

        m = ssh_dh_group16;

    } else {

        m = ssh_dh_group18;

    }

    cmp = bignum_cmp(m, modulus);

    if (cmp != 0) {

        return false;

    }

    cmp = bignum_cmp(ssh_dh_generator, generator);

    if (cmp != 0) {

        return false;

    }

    SSH_LOG(SSH_LOG_TRACE, "The received primes in FIPS are known");

    return true;

}

ssh_key ssh_dh_get_current_server_publickey(ssh_session session)

{

    if (session->current_crypto == NULL) {

        return NULL;

    }

    return session->current_crypto->server_pubkey;

}

/* Caller need to free the blob */

int ssh_dh_get_current_server_publickey_blob(ssh_session session,

                                     ssh_string *pubkey_blob)

{

    const ssh_key pubkey = ssh_dh_get_current_server_publickey(session);

    return ssh_pki_export_pubkey_blob(pubkey, pubkey_blob);

}

ssh_key ssh_dh_get_next_server_publickey(ssh_session session)

{

    return session->next_crypto->server_pubkey;

}

/* Caller need to free the blob */

int ssh_dh_get_next_server_publickey_blob(ssh_session session,

                                          ssh_string *pubkey_blob)

{

    const ssh_key pubkey = ssh_dh_get_next_server_publickey(session);

    return ssh_pki_export_pubkey_blob(pubkey, pubkey_blob);

}

/**

 * @internal

 *

 * @brief Convert a buffer into an unpadded base64 string.

 * The caller has to free the memory.

 *

 * @param  hash         What should be converted to a base64 string.

 *

 * @param  len          Length of the buffer to convert.

 *

 * @return              The base64 string or NULL on error.

 *

 * @see ssh_string_free_char()

 */

static char *ssh_get_b64_unpadded(const unsigned char *hash, size_t len)

{

    char *b64_padded = NULL;

    char *b64_unpadded = NULL;

    size_t k;

    b64_padded = (char *)bin_to_base64(hash, (int)len);

    if (b64_padded == NULL) {

        return NULL;

    }

    for (k = strlen(b64_padded); k != 0 && b64_padded[k-1] == '='; k--);

    b64_unpadded = strndup(b64_padded, k);

    SAFE_FREE(b64_padded);

    return b64_unpadded;

}

/**

 * @brief Get a hash as a human-readable hex- or base64-string.

 *

 * This gets an allocated fingerprint hash.  If it is a SHA sum, it will

 * return an unpadded base64 strings.  If it is a MD5 sum, it will return hex

 * string. Either way, the output is prepended by the hash-type.

 *

 * @warning Do NOT use MD5 or SHA1! Those hash functions are being deprecated.

 *

 * @param  type         Which sort of hash is given, use

 *                      SSH_PUBLICKEY_HASH_SHA256 or better.

 *

 * @param  hash         The hash to be converted to fingerprint.

 *

 * @param  len          Length of the buffer to convert.

 *

 * @return Returns the allocated fingerprint hash or NULL on error.

 *

 * @see ssh_string_free_char()

 */

char *ssh_get_fingerprint_hash(enum ssh_publickey_hash_type type,

                               unsigned char *hash,

                               size_t len)

{

    const char *prefix = "UNKNOWN";

    char *fingerprint = NULL;

    char *str = NULL;

    size_t str_len;

    int rc;

    switch (type) {

    case SSH_PUBLICKEY_HASH_SHA1:

    case SSH_PUBLICKEY_HASH_SHA256:

        fingerprint = ssh_get_b64_unpadded(hash, len);

        break;

    case SSH_PUBLICKEY_HASH_MD5:

        fingerprint = ssh_get_hexa(hash, len);

        break;

    }

    if (fingerprint == NULL) {

        return NULL;

    }

    switch (type) {

    case SSH_PUBLICKEY_HASH_MD5:

        prefix = "MD5";

        break;

    case SSH_PUBLICKEY_HASH_SHA1:

        prefix = "SHA1";

        break;

    case SSH_PUBLICKEY_HASH_SHA256:

        prefix = "SHA256";

        break;

    }

    str_len = strlen(prefix);

    if (str_len + 1 + strlen(fingerprint) + 1 < str_len) {

        SAFE_FREE(fingerprint);

        return NULL;

    }

    str_len += 1 + strlen(fingerprint) + 1;

    str = malloc(str_len);

    if (str == NULL) {

        SAFE_FREE(fingerprint);

        return NULL;

    }

    rc = snprintf(str, str_len, "%s:%s", prefix, fingerprint);

    SAFE_FREE(fingerprint);

    if (rc < 0 || rc < (int)(str_len - 1)) {

        SAFE_FREE(str);

    }

    return str;

}

/**

 * @brief Print a hash as a human-readable hex- or base64-string.

 *

 * This prints an unpadded base64 strings for SHA sums and hex strings for MD5

 * sum.  Either way, the output is prepended by the hash-type.

 *

 * @param  type         Which sort of hash is given. Use

 *                      SSH_PUBLICKEY_HASH_SHA256 or better.

 *

 * @param  hash         The hash to be converted to fingerprint.

 *

 * @param  len          Length of the buffer to convert.

 *

 * @see ssh_get_publickey_hash()

 * @see ssh_get_fingerprint_hash()

 */

void ssh_print_hash(enum ssh_publickey_hash_type type,

                    unsigned char *hash,

                    size_t len)

{

    char *fingerprint = NULL;

    fingerprint = ssh_get_fingerprint_hash(type,

                                           hash,

                                           len);

    if (fingerprint == NULL) {

        return;

    }

    fprintf(stderr, "%s\n", fingerprint);

    SAFE_FREE(fingerprint);

}

/** @} */