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101 lines
3.5 KiB
101 lines
3.5 KiB
/* crypt.c */
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/* it just contains the shit necessary to make blowfish-cbc work ... */
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/*
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Copyright 2003 Aris Adamantiadis
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This file is part of the SSH Library
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The SSH Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or (at your
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option) any later version.
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The SSH Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the SSH Library; see the file COPYING. If not, write to
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the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor, Boston,
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MA 02110-1301, USA. */
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#include <unistd.h>
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#include <stdlib.h>
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#include <string.h>
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#include <openssl/blowfish.h>
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#include <openssl/evp.h>
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#include <openssl/hmac.h>
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#include <netdb.h>
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#include "priv.h"
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#include "crypto.h"
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u32 packet_decrypt_len(SSH_SESSION *session, char *crypted){
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u32 *decrypted;
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if(session->current_crypto)
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packet_decrypt(session,crypted,session->current_crypto->in_cipher->blocksize);
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decrypted=(u32 *)crypted;
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ssh_say(3,"size decrypted : %lx\n",ntohl(*decrypted));
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return ntohl(*decrypted);
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}
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int packet_decrypt(SSH_SESSION *session, void *data,u32 len){
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struct crypto_struct *crypto=session->current_crypto->in_cipher;
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char *out=malloc(len);
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ssh_say(3,"Decrypting %d bytes data\n",len);
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crypto->set_decrypt_key(crypto,session->current_crypto->decryptkey);
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crypto->cbc_decrypt(crypto,data,out,len,session->current_crypto->decryptIV);
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memcpy(data,out,len);
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memset(out,0,len);
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free(out);
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return 0;
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}
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char * packet_encrypt(SSH_SESSION *session,void *data,u32 len){
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struct crypto_struct *crypto;
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HMAC_CTX *ctx;
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char *out;
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int finallen;
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u32 seq=ntohl(session->send_seq);
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if(!session->current_crypto)
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return NULL; /* nothing to do here */
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crypto= session->current_crypto->out_cipher;
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ssh_say(3,"seq num = %d, len = %d\n",session->send_seq,len);
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crypto->set_encrypt_key(crypto,session->current_crypto->encryptkey);
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out=malloc(len);
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ctx=hmac_init(session->current_crypto->encryptMAC,20,HMAC_SHA1);
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hmac_update(ctx,(unsigned char *)&seq,sizeof(u32));
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hmac_update(ctx,data,len);
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hmac_final(ctx,session->current_crypto->hmacbuf,&finallen);
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#ifdef DEBUG_CRYPTO
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ssh_print_hexa("mac :",data,len);
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if(finallen!=20)
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printf("Final len is %d\n",finallen);
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ssh_print_hexa("packet hmac",session->current_crypto->hmacbuf,20);
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#endif
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crypto->cbc_encrypt(crypto,data,out,len,session->current_crypto->encryptIV);
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memcpy(data,out,len);
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memset(out,0,len);
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free(out);
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return session->current_crypto->hmacbuf;
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}
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int packet_hmac_verify(SSH_SESSION *session,BUFFER *buffer,char *mac){
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HMAC_CTX *ctx;
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unsigned char hmacbuf[EVP_MAX_MD_SIZE];
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int len;
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u32 seq=htonl(session->recv_seq);
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ctx=hmac_init(session->current_crypto->decryptMAC,20,HMAC_SHA1);
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hmac_update(ctx,(unsigned char *)&seq,sizeof(u32));
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hmac_update(ctx,buffer_get(buffer),buffer_get_len(buffer));
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hmac_final(ctx,hmacbuf,&len);
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#ifdef DEBUG_CRYPTO
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ssh_print_hexa("received mac",mac,len);
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ssh_print_hexa("Computed mac",hmacbuf,len);
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ssh_print_hexa("seq",(unsigned char *)&seq,sizeof(u32));
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#endif
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return memcmp(mac,hmacbuf,len);
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}
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