diff options
Diffstat (limited to 'libssh/src/kex1.c')
-rw-r--r-- | libssh/src/kex1.c | 497 |
1 files changed, 0 insertions, 497 deletions
diff --git a/libssh/src/kex1.c b/libssh/src/kex1.c deleted file mode 100644 index 758054f8..00000000 --- a/libssh/src/kex1.c +++ /dev/null @@ -1,497 +0,0 @@ -/* - * kex.c - key exchange - * - * This file is part of the SSH Library - * - * Copyright (c) 2003-2008 by Aris Adamantiadis - * - * 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" - -#ifndef _WIN32 -#include <arpa/inet.h> -#endif - -#include "libssh/priv.h" -#include "libssh/buffer.h" -#include "libssh/crypto.h" -#include "libssh/kex.h" -#include "libssh/keys.h" -#include "libssh/session.h" -#include "libssh/ssh1.h" -#include "libssh/wrapper.h" - -/* SSHv1 functions */ - -/* makes a STRING contating 3 strings : ssh-rsa1,e and n */ -/* this is a public key in openssh's format */ -static ssh_string make_rsa1_string(ssh_string e, ssh_string n){ - ssh_buffer buffer = NULL; - ssh_string rsa = NULL; - ssh_string ret = NULL; - - buffer = ssh_buffer_new(); - rsa = ssh_string_from_char("ssh-rsa1"); - if (rsa == NULL) { - goto error; - } - - if (buffer_add_ssh_string(buffer, rsa) < 0) { - goto error; - } - if (buffer_add_ssh_string(buffer, e) < 0) { - goto error; - } - if (buffer_add_ssh_string(buffer, n) < 0) { - goto error; - } - - ret = ssh_string_new(ssh_buffer_get_len(buffer)); - if (ret == NULL) { - goto error; - } - - ssh_string_fill(ret, ssh_buffer_get_begin(buffer), ssh_buffer_get_len(buffer)); -error: - ssh_buffer_free(buffer); - ssh_string_free(rsa); - - return ret; -} - -static int build_session_id1(ssh_session session, ssh_string servern, - ssh_string hostn) { - MD5CTX md5 = NULL; - - md5 = md5_init(); - if (md5 == NULL) { - return -1; - } - -#ifdef DEBUG_CRYPTO - ssh_print_hexa("host modulus",ssh_string_data(hostn),ssh_string_len(hostn)); - ssh_print_hexa("server modulus",ssh_string_data(servern),ssh_string_len(servern)); -#endif - md5_update(md5,ssh_string_data(hostn),ssh_string_len(hostn)); - md5_update(md5,ssh_string_data(servern),ssh_string_len(servern)); - md5_update(md5,session->next_crypto->server_kex.cookie,8); - if(session->next_crypto->session_id != NULL) - SAFE_FREE(session->next_crypto->session_id); - session->next_crypto->session_id = malloc(MD5_DIGEST_LEN); - if(session->next_crypto->session_id == NULL){ - ssh_set_error_oom(session); - return SSH_ERROR; - } - md5_final(session->next_crypto->session_id,md5); -#ifdef DEBUG_CRYPTO - ssh_print_hexa("session_id",session->next_crypto->session_id,MD5_DIGEST_LEN); -#endif - - return 0; -} - -/* returns 1 if the modulus of k1 is < than the one of k2 */ -static int modulus_smaller(ssh_public_key k1, ssh_public_key k2){ - bignum n1; - bignum n2; - int res; -#ifdef HAVE_LIBGCRYPT - gcry_sexp_t sexp; - sexp=gcry_sexp_find_token(k1->rsa_pub,"n",0); - n1=gcry_sexp_nth_mpi(sexp,1,GCRYMPI_FMT_USG); - gcry_sexp_release(sexp); - sexp=gcry_sexp_find_token(k2->rsa_pub,"n",0); - n2=gcry_sexp_nth_mpi(sexp,1,GCRYMPI_FMT_USG); - gcry_sexp_release(sexp); -#elif defined HAVE_LIBCRYPTO - n1=k1->rsa_pub->n; - n2=k2->rsa_pub->n; -#endif - if(bignum_cmp(n1,n2)<0) - res=1; - else - res=0; -#ifdef HAVE_LIBGCRYPT - bignum_free(n1); - bignum_free(n2); -#endif - return res; - -} - -static ssh_string ssh_encrypt_rsa1(ssh_session session, - ssh_string data, - ssh_public_key key) { - ssh_string str = NULL; - size_t len = ssh_string_len(data); - size_t size = 0; -#ifdef HAVE_LIBGCRYPT - const char *tmp = NULL; - gcry_sexp_t ret_sexp; - gcry_sexp_t data_sexp; - - if (gcry_sexp_build(&data_sexp, NULL, "(data(flags pkcs1)(value %b))", - len, ssh_string_data(data))) { - ssh_set_error(session, SSH_FATAL, "RSA1 encrypt: libgcrypt error"); - return NULL; - } - if (gcry_pk_encrypt(&ret_sexp, data_sexp, key->rsa_pub)) { - gcry_sexp_release(data_sexp); - ssh_set_error(session, SSH_FATAL, "RSA1 encrypt: libgcrypt error"); - return NULL; - } - - gcry_sexp_release(data_sexp); - - data_sexp = gcry_sexp_find_token(ret_sexp, "a", 0); - if (data_sexp == NULL) { - ssh_set_error(session, SSH_FATAL, "RSA1 encrypt: libgcrypt error"); - gcry_sexp_release(ret_sexp); - return NULL; - } - tmp = gcry_sexp_nth_data(data_sexp, 1, &size); - if (*tmp == 0) { - size--; - tmp++; - } - - str = ssh_string_new(size); - if (str == NULL) { - ssh_set_error(session, SSH_FATAL, "Not enough space"); - gcry_sexp_release(data_sexp); - gcry_sexp_release(ret_sexp); - return NULL; - } - ssh_string_fill(str, tmp, size); - - gcry_sexp_release(data_sexp); - gcry_sexp_release(ret_sexp); -#elif defined HAVE_LIBCRYPTO - size = RSA_size(key->rsa_pub); - - str = ssh_string_new(size); - if (str == NULL) { - ssh_set_error(session, SSH_FATAL, "Not enough space"); - return NULL; - } - - if (RSA_public_encrypt(len, ssh_string_data(data), ssh_string_data(str), key->rsa_pub, - RSA_PKCS1_PADDING) < 0) { - ssh_string_free(str); - return NULL; - } -#endif - - return str; -} - -#define ABS(A) ( (A)<0 ? -(A):(A) ) -static ssh_string encrypt_session_key(ssh_session session, ssh_public_key srvkey, - ssh_public_key hostkey, int slen, int hlen) { - unsigned char buffer[32] = {0}; - int i; - ssh_string data1 = NULL; - ssh_string data2 = NULL; - if(session->next_crypto->encryptkey != NULL) - SAFE_FREE(session->next_crypto->encryptkey); - if(session->next_crypto->decryptkey != NULL) - SAFE_FREE(session->next_crypto->decryptkey); - if(session->next_crypto->encryptIV != NULL) - SAFE_FREE(session->next_crypto->encryptIV); - if(session->next_crypto->decryptIV != NULL) - SAFE_FREE(session->next_crypto->decryptIV); - session->next_crypto->encryptkey = malloc(32); - session->next_crypto->decryptkey = malloc(32); - session->next_crypto->encryptIV = malloc(32); - session->next_crypto->decryptIV = malloc(32); - if(session->next_crypto->encryptkey == NULL || - session->next_crypto->decryptkey == NULL || - session->next_crypto->encryptIV == NULL || - session->next_crypto->decryptIV == NULL){ - ssh_set_error_oom(session); - return NULL; - } - /* first, generate a session key */ - ssh_get_random(session->next_crypto->encryptkey, 32, 1); - memcpy(buffer, session->next_crypto->encryptkey, 32); - memcpy(session->next_crypto->decryptkey, session->next_crypto->encryptkey, 32); - memset(session->next_crypto->encryptIV, 0, 32); - memset(session->next_crypto->decryptIV, 0, 32); - -#ifdef DEBUG_CRYPTO - ssh_print_hexa("session key",buffer,32); -#endif - - /* xor session key with session_id */ - for (i = 0; i < 16; i++) { - buffer[i] ^= session->next_crypto->session_id[i]; - } - data1 = ssh_string_new(32); - if (data1 == NULL) { - return NULL; - } - ssh_string_fill(data1, buffer, 32); - if (ABS(hlen - slen) < 128){ - SSH_LOG(SSH_LOG_FUNCTIONS, - "Difference between server modulus and host modulus is only %d. " - "It's illegal and may not work", - ABS(hlen - slen)); - } - - if (modulus_smaller(srvkey, hostkey)) { - data2 = ssh_encrypt_rsa1(session, data1, srvkey); - ssh_string_free(data1); - data1 = NULL; - if (data2 == NULL) { - return NULL; - } - data1 = ssh_encrypt_rsa1(session, data2, hostkey); - ssh_string_free(data2); - if (data1 == NULL) { - return NULL; - } - } else { - data2 = ssh_encrypt_rsa1(session, data1, hostkey); - ssh_string_free(data1); - data1 = NULL; - if (data2 == NULL) { - return NULL; - } - data1 = ssh_encrypt_rsa1(session, data2, srvkey); - ssh_string_free(data2); - if (data1 == NULL) { - return NULL; - } - } - - return data1; -} - -/* 2 SSH_SMSG_PUBLIC_KEY - * - * 8 bytes anti_spoofing_cookie - * 32-bit int server_key_bits - * mp-int server_key_public_exponent - * mp-int server_key_public_modulus - * 32-bit int host_key_bits - * mp-int host_key_public_exponent - * mp-int host_key_public_modulus - * 32-bit int protocol_flags - * 32-bit int supported_ciphers_mask - * 32-bit int supported_authentications_mask - */ -/** - * @brief Wait for a SSH_SMSG_PUBLIC_KEY and does the key exchange - */ -SSH_PACKET_CALLBACK(ssh_packet_publickey1){ - ssh_string server_exp = NULL; - ssh_string server_mod = NULL; - ssh_string host_exp = NULL; - ssh_string host_mod = NULL; - ssh_string serverkey = NULL; - ssh_string hostkey = NULL; - ssh_public_key srv = NULL; - ssh_public_key host = NULL; - uint32_t server_bits; - uint32_t host_bits; - uint32_t protocol_flags; - uint32_t supported_ciphers_mask; - uint32_t supported_authentications_mask; - ssh_string enc_session = NULL; - uint16_t bits; - int ko; - uint32_t support_3DES = 0; - uint32_t support_DES = 0; - - (void)type; - (void)user; - SSH_LOG(SSH_LOG_PROTOCOL, "Got a SSH_SMSG_PUBLIC_KEY"); - if(session->session_state != SSH_SESSION_STATE_INITIAL_KEX){ - ssh_set_error(session,SSH_FATAL,"SSH_KEXINIT received in wrong state"); - goto error; - } - if (buffer_get_data(packet, session->next_crypto->server_kex.cookie, 8) != 8) { - ssh_set_error(session, SSH_FATAL, "Can't get cookie in buffer"); - goto error; - } - - buffer_get_u32(packet, &server_bits); - server_exp = buffer_get_mpint(packet); - if (server_exp == NULL) { - goto error; - } - server_mod = buffer_get_mpint(packet); - if (server_mod == NULL) { - goto error; - } - buffer_get_u32(packet, &host_bits); - host_exp = buffer_get_mpint(packet); - if (host_exp == NULL) { - goto error; - } - host_mod = buffer_get_mpint(packet); - if (host_mod == NULL) { - goto error; - } - buffer_get_u32(packet, &protocol_flags); - buffer_get_u32(packet, &supported_ciphers_mask); - ko = buffer_get_u32(packet, &supported_authentications_mask); - - if ((ko != sizeof(uint32_t)) || !host_mod || !host_exp - || !server_mod || !server_exp) { - SSH_LOG(SSH_LOG_RARE, "Invalid SSH_SMSG_PUBLIC_KEY packet"); - ssh_set_error(session, SSH_FATAL, "Invalid SSH_SMSG_PUBLIC_KEY packet"); - goto error; - } - - server_bits = ntohl(server_bits); - host_bits = ntohl(host_bits); - protocol_flags = ntohl(protocol_flags); - supported_ciphers_mask = ntohl(supported_ciphers_mask); - supported_authentications_mask = ntohl(supported_authentications_mask); - SSH_LOG(SSH_LOG_PROTOCOL, - "Server bits: %d; Host bits: %d; Protocol flags: %.8lx; " - "Cipher mask: %.8lx; Auth mask: %.8lx", - server_bits, - host_bits, - (unsigned long int) protocol_flags, - (unsigned long int) supported_ciphers_mask, - (unsigned long int) supported_authentications_mask); - - serverkey = make_rsa1_string(server_exp, server_mod); - if (serverkey == NULL) { - goto error; - } - hostkey = make_rsa1_string(host_exp,host_mod); - if (hostkey == NULL) { - goto error; - } - if (build_session_id1(session, server_mod, host_mod) < 0) { - goto error; - } - - srv = publickey_from_string(session, serverkey); - if (srv == NULL) { - goto error; - } - host = publickey_from_string(session, hostkey); - if (host == NULL) { - goto error; - } - - session->next_crypto->server_pubkey = ssh_string_copy(hostkey); - if (session->next_crypto->server_pubkey == NULL) { - goto error; - } - session->next_crypto->server_pubkey_type = "ssh-rsa1"; - - /* now, we must choose an encryption algo */ - /* hardcode 3des */ - // - support_3DES = (supported_ciphers_mask & (1<<SSH_CIPHER_3DES)); - support_DES = (supported_ciphers_mask & (1<<SSH_CIPHER_DES)); - if(!support_3DES && !support_DES){ - ssh_set_error(session, SSH_FATAL, "Remote server doesn't accept 3DES"); - goto error; - } - SSH_LOG(SSH_LOG_PROTOCOL, "Sending SSH_CMSG_SESSION_KEY"); - - if (buffer_add_u8(session->out_buffer, SSH_CMSG_SESSION_KEY) < 0) { - goto error; - } - if (buffer_add_u8(session->out_buffer, support_3DES ? SSH_CIPHER_3DES : SSH_CIPHER_DES) < 0) { - goto error; - } - if (ssh_buffer_add_data(session->out_buffer, session->next_crypto->server_kex.cookie, 8) < 0) { - goto error; - } - - enc_session = encrypt_session_key(session, srv, host, server_bits, host_bits); - if (enc_session == NULL) { - goto error; - } - - bits = ssh_string_len(enc_session) * 8 - 7; - SSH_LOG(SSH_LOG_PROTOCOL, "%d bits, %" PRIdS " bytes encrypted session", - bits, ssh_string_len(enc_session)); - bits = htons(bits); - /* the encrypted mpint */ - if (ssh_buffer_add_data(session->out_buffer, &bits, sizeof(uint16_t)) < 0) { - goto error; - } - if (ssh_buffer_add_data(session->out_buffer, ssh_string_data(enc_session), - ssh_string_len(enc_session)) < 0) { - goto error; - } - /* the protocol flags */ - if (buffer_add_u32(session->out_buffer, 0) < 0) { - goto error; - } - session->session_state=SSH_SESSION_STATE_KEXINIT_RECEIVED; - if (packet_send(session) == SSH_ERROR) { - goto error; - } - - /* we can set encryption */ - if(crypt_set_algorithms(session, support_3DES ? SSH_3DES : SSH_DES)){ - goto error; - } - - session->current_crypto = session->next_crypto; - session->next_crypto = NULL; - goto end; -error: - session->session_state=SSH_SESSION_STATE_ERROR; -end: - - ssh_string_free(host_mod); - ssh_string_free(host_exp); - ssh_string_free(server_mod); - ssh_string_free(server_exp); - ssh_string_free(serverkey); - ssh_string_free(hostkey); - ssh_string_free(enc_session); - - publickey_free(srv); - publickey_free(host); - - return SSH_PACKET_USED; -} - -int ssh_get_kex1(ssh_session session) { - SSH_LOG(SSH_LOG_PROTOCOL, "Waiting for a SSH_SMSG_PUBLIC_KEY"); - - /* Here the callback is called */ - while(session->session_state==SSH_SESSION_STATE_INITIAL_KEX){ - ssh_handle_packets(session, SSH_TIMEOUT_USER); - } - if (session->session_state==SSH_SESSION_STATE_ERROR) { - return SSH_ERROR; - } - SSH_LOG(SSH_LOG_PROTOCOL, "Waiting for a SSH_SMSG_SUCCESS"); - /* Waiting for SSH_SMSG_SUCCESS */ - while(session->session_state==SSH_SESSION_STATE_KEXINIT_RECEIVED){ - ssh_handle_packets(session, SSH_TIMEOUT_USER); - } - if(session->session_state==SSH_SESSION_STATE_ERROR) { - return SSH_ERROR; - } - SSH_LOG(SSH_LOG_PROTOCOL, "received SSH_SMSG_SUCCESS\n"); - - return SSH_OK; -} |