/*
* This file is part of the SSH Library
*
* Copyright (c) 2003-2009 by Aris Adamantiadis
*
* This 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.
*
* This 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 this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/*
* crypto.h is an include file for internal cryptographic structures of libssh
*/
#ifndef _CRYPTO_H_
#define _CRYPTO_H_
#include <stdbool.h>
#include "config.h"
#ifdef HAVE_LIBGCRYPT
#include <gcrypt.h>
#elif defined(HAVE_LIBMBEDCRYPTO)
#include <mbedtls/gcm.h>
#endif
#include "libssh/wrapper.h"
#ifdef cbc_encrypt
#undef cbc_encrypt
#endif
#ifdef cbc_decrypt
#undef cbc_decrypt
#endif
#ifdef HAVE_OPENSSL_ECDH_H
#include <openssl/ecdh.h>
#endif
#include "libssh/dh.h"
#include "libssh/ecdh.h"
#include "libssh/kex.h"
#include "libssh/curve25519.h"
#define DIGEST_MAX_LEN 64
#define AES_GCM_TAGLEN 16
#define AES_GCM_IVLEN 12
enum ssh_key_exchange_e {
/* diffie-hellman-group1-sha1 */
SSH_KEX_DH_GROUP1_SHA1=1,
/* diffie-hellman-group14-sha1 */
SSH_KEX_DH_GROUP14_SHA1,
#ifdef WITH_GEX
/* diffie-hellman-group-exchange-sha1 */
SSH_KEX_DH_GEX_SHA1,
/* diffie-hellman-group-exchange-sha256 */
SSH_KEX_DH_GEX_SHA256,
#endif /* WITH_GEX */
/* ecdh-sha2-nistp256 */
SSH_KEX_ECDH_SHA2_NISTP256,
/* ecdh-sha2-nistp384 */
SSH_KEX_ECDH_SHA2_NISTP384,
/* ecdh-sha2-nistp521 */
SSH_KEX_ECDH_SHA2_NISTP521,
/* curve25519-sha256@libssh.org */
SSH_KEX_CURVE25519_SHA256_LIBSSH_ORG,
/* curve25519-sha256 */
SSH_KEX_CURVE25519_SHA256,
/* diffie-hellman-group16-sha512 */
SSH_KEX_DH_GROUP16_SHA512,
/* diffie-hellman-group18-sha512 */
SSH_KEX_DH_GROUP18_SHA512,
};
enum ssh_cipher_e {
SSH_NO_CIPHER=0,
#ifdef WITH_BLOWFISH_CIPHER
SSH_BLOWFISH_CBC,
#endif /* WITH_BLOWFISH_CIPHER */
SSH_3DES_CBC,
SSH_AES128_CBC,
SSH_AES192_CBC,
SSH_AES256_CBC,
SSH_AES128_CTR,
SSH_AES192_CTR,
SSH_AES256_CTR,
SSH_AEAD_AES128_GCM,
SSH_AEAD_AES256_GCM,
SSH_AEAD_CHACHA20_POLY1305
};
struct dh_ctx;
struct ssh_crypto_struct {
bignum shared_secret;
struct dh_ctx *dh_ctx;
#ifdef WITH_GEX
size_t dh_pmin; int dh_pn; int dh_pmax; /* preferred group parameters */
#endif /* WITH_GEX */
#ifdef HAVE_ECDH
#ifdef HAVE_OPENSSL_ECC
EC_KEY *ecdh_privkey;
#elif defined HAVE_GCRYPT_ECC
gcry_sexp_t ecdh_privkey;
#elif defined HAVE_LIBMBEDCRYPTO
mbedtls_ecp_keypair *ecdh_privkey;
#endif
ssh_string ecdh_client_pubkey;
ssh_string ecdh_server_pubkey;
#endif
#ifdef HAVE_CURVE25519
ssh_curve25519_privkey curve25519_privkey;
ssh_curve25519_pubkey curve25519_client_pubkey;
ssh_curve25519_pubkey curve25519_server_pubkey;
#endif
ssh_string dh_server_signature; /* information used by dh_handshake. */
size_t digest_len; /* len of the two fields below */
unsigned char *session_id;
unsigned char *secret_hash; /* Secret hash is same as session id until re-kex */
unsigned char *encryptIV;
unsigned char *decryptIV;
unsigned char *decryptkey;
unsigned char *encryptkey;
unsigned char *encryptMAC;
unsigned char *decryptMAC;
unsigned char hmacbuf[DIGEST_MAX_LEN];
struct ssh_cipher_struct *in_cipher, *out_cipher; /* the cipher structures/objects */
enum ssh_hmac_e in_hmac, out_hmac; /* the MAC algorithms used */
bool in_hmac_etm, out_hmac_etm; /* Whether EtM mode is used or not */
ssh_key server_pubkey;
int do_compress_out; /* idem */
int do_compress_in; /* don't set them, set the option instead */
int delayed_compress_in; /* Use of zlib@openssh.org */
int delayed_compress_out;
void *compress_out_ctx; /* don't touch it */
void *compress_in_ctx; /* really, don't */
/* kex sent by server, client, and mutually elected methods */
struct ssh_kex_struct server_kex;
struct ssh_kex_struct client_kex;
char *kex_methods[SSH_KEX_METHODS];
enum ssh_key_exchange_e kex_type;
enum ssh_kdf_digest digest_type; /* Digest type for session keys derivation */
enum ssh_crypto_direction_e used; /* Is this crypto still used for either of directions? */
};
struct ssh_cipher_struct {
const char *name; /* ssh name of the algorithm */
unsigned int blocksize; /* blocksize of the algo */
enum ssh_cipher_e ciphertype;
uint32_t lenfield_blocksize; /* blocksize of the packet length field */
size_t keylen; /* length of the key structure */
#ifdef HAVE_LIBGCRYPT
gcry_cipher_hd_t *key;
unsigned char last_iv[AES_GCM_IVLEN];
#elif defined HAVE_LIBCRYPTO
struct ssh_3des_key_schedule *des3_key;
struct ssh_aes_key_schedule *aes_key;
const EVP_CIPHER *cipher;
EVP_CIPHER_CTX *ctx;
#elif defined HAVE_LIBMBEDCRYPTO
mbedtls_cipher_context_t encrypt_ctx;
mbedtls_cipher_context_t decrypt_ctx;
mbedtls_cipher_type_t type;
#ifdef MBEDTLS_GCM_C
mbedtls_gcm_context gcm_ctx;
unsigned char last_iv[AES_GCM_IVLEN];
#endif /* MBEDTLS_GCM_C */
#endif
struct chacha20_poly1305_keysched *chacha20_schedule;
unsigned int keysize; /* bytes of key used. != keylen */
size_t tag_size; /* overhead required for tag */
/* Counters for rekeying initialization */
uint32_t packets;
uint64_t blocks;
/* Rekeying limit for the cipher or manually enforced */
uint64_t max_blocks;
/* sets the new key for immediate use */
int (*set_encrypt_key)(struct ssh_cipher_struct *cipher, void *key, void *IV);
int (*set_decrypt_key)(struct ssh_cipher_struct *cipher, void *key, void *IV);
void (*encrypt)(struct ssh_cipher_struct *cipher,
void *in,
void *out,
size_t len);
void (*decrypt)(struct ssh_cipher_struct *cipher,
void *in,
void *out,
size_t len);
void (*aead_encrypt)(struct ssh_cipher_struct *cipher, void *in, void *out,
size_t len, uint8_t *mac, uint64_t seq);
int (*aead_decrypt_length)(struct ssh_cipher_struct *cipher, void *in,
uint8_t *out, size_t len, uint64_t seq);
int (*aead_decrypt)(struct ssh_cipher_struct *cipher, void *complete_packet, uint8_t *out,
size_t encrypted_size, uint64_t seq);
void (*cleanup)(struct ssh_cipher_struct *cipher);
};
const struct ssh_cipher_struct *ssh_get_chacha20poly1305_cipher(void);
int sshkdf_derive_key(struct ssh_crypto_struct *crypto,
unsigned char *key, size_t key_len,
int key_type, unsigned char *output,
size_t requested_len);
#endif /* _CRYPTO_H_ */