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/*
* crypt.c - blowfish-cbc code
*
* This file is part of the SSH Library
*
* Copyright (c) 2003 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.
*
* vim: ts=2 sw=2 et cindent
*/
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#ifdef OPENSSL_CRYPTO
#include <openssl/blowfish.h>
#include <openssl/evp.h>
#include <openssl/hmac.h>
#endif
#include "libssh/priv.h"
#include "libssh/crypto.h"
u32 packet_decrypt_len(SSH_SESSION *session, char *crypted){
u32 decrypted;
if (session->current_crypto) {
if (packet_decrypt(session, crypted,
session->current_crypto->in_cipher->blocksize) < 0) {
return 0;
}
}
memcpy(&decrypted,crypted,sizeof(decrypted));
ssh_log(session, SSH_LOG_PACKET,
"Packet size decrypted: %lu (0x%lx)",
(long unsigned int) ntohl(decrypted),
(long unsigned int) ntohl(decrypted));
return ntohl(decrypted);
}
int packet_decrypt(SSH_SESSION *session, void *data,u32 len) {
struct crypto_struct *crypto = session->current_crypto->in_cipher;
char *out = NULL;
out = malloc(len);
if (out == NULL) {
return -1;
}
ssh_log(session,SSH_LOG_PACKET, "Decrypting %d bytes", len);
#ifdef HAVE_LIBGCRYPT
crypto->set_decrypt_key(crypto,session->current_crypto->decryptkey,session->current_crypto->decryptIV);
crypto->cbc_decrypt(crypto,data,out,len);
#elif defined HAVE_LIBCRYPTO
crypto->set_decrypt_key(crypto,session->current_crypto->decryptkey);
crypto->cbc_decrypt(crypto,data,out,len,session->current_crypto->decryptIV);
#endif
memcpy(data,out,len);
memset(out,0,len);
SAFE_FREE(out);
return 0;
}
unsigned char *packet_encrypt(SSH_SESSION *session, void *data, u32 len) {
struct crypto_struct *crypto = NULL;
HMACCTX ctx = NULL;
char *out = NULL;
unsigned int finallen;
u32 seq;
if (!session->current_crypto) {
return NULL; /* nothing to do here */
}
out = malloc(len);
if (out == NULL) {
return NULL;
}
seq = ntohl(session->send_seq);
crypto = session->current_crypto->out_cipher;
ssh_log(session, SSH_LOG_PACKET,
"Encrypting packet with seq num: %d, len: %d",
session->send_seq,len);
#ifdef HAVE_LIBGCRYPT
crypto->set_encrypt_key(crypto, session->current_crypto->encryptkey,
session->current_crypto->encryptIV);
#elif defined HAVE_LIBCRYPTO
crypto->set_encrypt_key(crypto, session->current_crypto->encryptkey);
#endif
if (session->version == 2) {
ctx = hmac_init(session->current_crypto->encryptMAC,20,HMAC_SHA1);
if (ctx == NULL) {
SAFE_FREE(out);
return NULL;
}
hmac_update(ctx,(unsigned char *)&seq,sizeof(u32));
hmac_update(ctx,data,len);
hmac_final(ctx,session->current_crypto->hmacbuf,&finallen);
#ifdef DEBUG_CRYPTO
ssh_print_hexa("mac: ",data,len);
if (finallen != 20) {
printf("Final len is %d\n",finallen);
}
ssh_print_hexa("Packet hmac", session->current_crypto->hmacbuf, 20);
#endif
}
#ifdef HAVE_LIBGCRYPT
crypto->cbc_encrypt(crypto, data, out, len);
#elif defined HAVE_LIBCRYPTO
crypto->cbc_encrypt(crypto, data, out, len,
session->current_crypto->encryptIV);
#endif
memcpy(data, out, len);
memset(out, 0, len);
SAFE_FREE(out);
if (session->version == 2) {
return session->current_crypto->hmacbuf;
}
return NULL;
}
/* TODO FIXME think about the return value isn't 0 enough and -1 on error */
int packet_hmac_verify(SSH_SESSION *session,BUFFER *buffer,unsigned char *mac){
HMACCTX ctx;
unsigned char hmacbuf[EVP_MAX_MD_SIZE];
unsigned int len;
u32 seq=htonl(session->recv_seq);
ctx=hmac_init(session->current_crypto->decryptMAC,20,HMAC_SHA1);
if (ctx == NULL) {
return -1;
}
hmac_update(ctx,(unsigned char *)&seq,sizeof(u32));
hmac_update(ctx,buffer_get(buffer),buffer_get_len(buffer));
hmac_final(ctx,hmacbuf,&len);
#ifdef DEBUG_CRYPTO
ssh_print_hexa("received mac",mac,len);
ssh_print_hexa("Computed mac",hmacbuf,len);
ssh_print_hexa("seq",(unsigned char *)&seq,sizeof(u32));
#endif
return memcmp(mac,hmacbuf,len);
}
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