[openssh.git] / cipher.c

/*
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 *
 * As far as I am concerned, the code I have written for this software
 * can be used freely for any purpose.  Any derived versions of this
 * software must be clearly marked as such, and if the derived work is
 * incompatible with the protocol description in the RFC file, it must be
 * called by a name other than "ssh" or "Secure Shell".
 *
 *
 * Copyright (c) 1999 Niels Provos.  All rights reserved.
 * Copyright (c) 1999, 2000 Markus Friedl.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "includes.h"
RCSID("$OpenBSD: cipher.c,v 1.52 2002/02/18 13:05:32 markus Exp $");

#include "xmalloc.h"
#include "log.h"
#include "cipher.h"

#include <openssl/md5.h>
#include "rijndael.h"

#if OPENSSL_VERSION_NUMBER < 0x00906000L
#define SSH_OLD_EVP
#define EVP_CIPHER_CTX_get_app_data(e)          ((e)->app_data)
#endif

static EVP_CIPHER *evp_ssh1_3des(void);
static EVP_CIPHER *evp_ssh1_bf(void);
static EVP_CIPHER *evp_rijndael(void);

struct Cipher {
	char	*name;
	int	number;		/* for ssh1 only */
	u_int	block_size;
	u_int	key_len;
	EVP_CIPHER	*(*evptype)(void);
} ciphers[] = {
	{ "none", 		SSH_CIPHER_NONE, 8, 0, EVP_enc_null },
	{ "des", 		SSH_CIPHER_DES, 8, 8, EVP_des_cbc },
	{ "3des", 		SSH_CIPHER_3DES, 8, 16, evp_ssh1_3des },
	{ "blowfish", 		SSH_CIPHER_BLOWFISH, 8, 32, evp_ssh1_bf },

	{ "3des-cbc", 		SSH_CIPHER_SSH2, 8, 24, EVP_des_ede3_cbc },
	{ "blowfish-cbc", 	SSH_CIPHER_SSH2, 8, 16, EVP_bf_cbc },
	{ "cast128-cbc", 	SSH_CIPHER_SSH2, 8, 16, EVP_cast5_cbc },
	{ "arcfour", 		SSH_CIPHER_SSH2, 8, 16, EVP_rc4 },
	{ "aes128-cbc", 	SSH_CIPHER_SSH2, 16, 16, evp_rijndael },
	{ "aes192-cbc", 	SSH_CIPHER_SSH2, 16, 24, evp_rijndael },
	{ "aes256-cbc", 	SSH_CIPHER_SSH2, 16, 32, evp_rijndael },

	{ NULL,			SSH_CIPHER_ILLEGAL, 0, 0, NULL }
};

/*--*/

u_int	
cipher_blocksize(Cipher *c)
{
	return (c->block_size);
}
u_int	
cipher_keylen(Cipher *c)
{
	return (c->key_len);
}

u_int
cipher_mask_ssh1(int client)
{
	u_int mask = 0;
	mask |= 1 << SSH_CIPHER_3DES;		/* Mandatory */
	mask |= 1 << SSH_CIPHER_BLOWFISH;
	if (client) {
		mask |= 1 << SSH_CIPHER_DES;
	}
	return mask;
}

Cipher *
cipher_by_name(const char *name)
{
	Cipher *c;
	for (c = ciphers; c->name != NULL; c++)
		if (strcasecmp(c->name, name) == 0)
			return c;
	return NULL;
}

Cipher *
cipher_by_number(int id)
{
	Cipher *c;
	for (c = ciphers; c->name != NULL; c++)
		if (c->number == id)
			return c;
	return NULL;
}

#define	CIPHER_SEP	","
int
ciphers_valid(const char *names)
{
	Cipher *c;
	char *ciphers, *cp;
	char *p;

	if (names == NULL || strcmp(names, "") == 0)
		return 0;
	ciphers = cp = xstrdup(names);
	for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
	    (p = strsep(&cp, CIPHER_SEP))) {
		c = cipher_by_name(p);
		if (c == NULL || c->number != SSH_CIPHER_SSH2) {
			debug("bad cipher %s [%s]", p, names);
			xfree(ciphers);
			return 0;
		} else {
			debug3("cipher ok: %s [%s]", p, names);
		}
	}
	debug3("ciphers ok: [%s]", names);
	xfree(ciphers);
	return 1;
}

/*
 * Parses the name of the cipher.  Returns the number of the corresponding
 * cipher, or -1 on error.
 */

int
cipher_number(const char *name)
{
	Cipher *c;
	if (name == NULL)
		return -1;
	c = cipher_by_name(name);
	return (c==NULL) ? -1 : c->number;
}

char *
cipher_name(int id)
{
	Cipher *c = cipher_by_number(id);
	return (c==NULL) ? "<unknown>" : c->name;
}

void
cipher_init(CipherContext *cc, Cipher *cipher,
    const u_char *key, u_int keylen, const u_char *iv, u_int ivlen,
    int encrypt)
{
	static int dowarn = 1;
#ifdef SSH_OLD_EVP
	EVP_CIPHER *type;
#else
	const EVP_CIPHER *type;
#endif
	int klen;

	if (cipher->number == SSH_CIPHER_DES) {
		if (dowarn) {
			error("Warning: use of DES is strongly discouraged "
			    "due to cryptographic weaknesses");
			dowarn = 0;
		}
		if (keylen > 8)
			keylen = 8;
	}
	cc->plaintext = (cipher->number == SSH_CIPHER_NONE);

	if (keylen < cipher->key_len)
		fatal("cipher_init: key length %d is insufficient for %s.",
		    keylen, cipher->name);
	if (iv != NULL && ivlen < cipher->block_size)
		fatal("cipher_init: iv length %d is insufficient for %s.",
		    ivlen, cipher->name);
	cc->cipher = cipher;

	type = (*cipher->evptype)();

	EVP_CIPHER_CTX_init(&cc->evp);
#ifdef SSH_OLD_EVP
	if (type->key_len > 0 && type->key_len != keylen) {
		debug("cipher_init: set keylen (%d -> %d)",
		    type->key_len, keylen);
		type->key_len = keylen;
	}
	EVP_CipherInit(&cc->evp, type, (u_char *)key, (u_char *)iv,
	    (encrypt == CIPHER_ENCRYPT));
#else
	if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
	    (encrypt == CIPHER_ENCRYPT)) == 0)
		fatal("cipher_init: EVP_CipherInit failed for %s",
		    cipher->name);
	klen = EVP_CIPHER_CTX_key_length(&cc->evp);
	if (klen > 0 && keylen != klen) {
		debug("cipher_init: set keylen (%d -> %d)", klen, keylen);
		if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
			fatal("cipher_init: set keylen failed (%d -> %d)",
			    klen, keylen);
	}
	if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
		fatal("cipher_init: EVP_CipherInit: set key failed for %s",
		    cipher->name);
#endif
}

void
cipher_crypt(CipherContext *cc, u_char *dest, const u_char *src, u_int len)
{
	if (len % cc->cipher->block_size)
		fatal("cipher_encrypt: bad plaintext length %d", len);
#ifdef SSH_OLD_EVP
	EVP_Cipher(&cc->evp, dest, (u_char *)src, len);
#else
	if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
		fatal("evp_crypt: EVP_Cipher failed");
#endif
}

void
cipher_cleanup(CipherContext *cc)
{
#ifdef SSH_OLD_EVP
	EVP_CIPHER_CTX_cleanup(&cc->evp);
#else
	if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
		error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
#endif
}

/*
 * Selects the cipher, and keys if by computing the MD5 checksum of the
 * passphrase and using the resulting 16 bytes as the key.
 */

void
cipher_set_key_string(CipherContext *cc, Cipher *cipher,
    const char *passphrase, int encrypt)
{
	MD5_CTX md;
	u_char digest[16];

	MD5_Init(&md);
	MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
	MD5_Final(digest, &md);

	cipher_init(cc, cipher, digest, 16, NULL, 0, encrypt);

	memset(digest, 0, sizeof(digest));
	memset(&md, 0, sizeof(md));
}

/* Implementations for other non-EVP ciphers */

/*
 * This is used by SSH1:
 *
 * What kind of triple DES are these 2 routines?
 *
 * Why is there a redundant initialization vector?
 *
 * If only iv3 was used, then, this would till effect have been
 * outer-cbc. However, there is also a private iv1 == iv2 which
 * perhaps makes differential analysis easier. On the other hand, the
 * private iv1 probably makes the CRC-32 attack ineffective. This is a
 * result of that there is no longer any known iv1 to use when
 * choosing the X block.
 */
struct ssh1_3des_ctx
{
	EVP_CIPHER_CTX	k1, k2, k3;
};
static int
ssh1_3des_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
    int enc)
{
	struct ssh1_3des_ctx *c;
	u_char *k1, *k2, *k3;

	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
		c = xmalloc(sizeof(*c));
		EVP_CIPHER_CTX_set_app_data(ctx, c);
	}
	if (key == NULL)
		return (1);
	if (enc == -1)
		enc = ctx->encrypt;
	k1 = k2 = k3 = (u_char *) key;
	k2 += 8;
	if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) {
		if (enc)
			k3 += 16;
		else
			k1 += 16;
	}
	EVP_CIPHER_CTX_init(&c->k1);
	EVP_CIPHER_CTX_init(&c->k2);
	EVP_CIPHER_CTX_init(&c->k3);
#ifdef SSH_OLD_EVP
	EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc);
	EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc);
	EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc);
#else
	if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 ||
	    EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 ||
	    EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
		memset(c, 0, sizeof(*c));
		xfree(c);
		EVP_CIPHER_CTX_set_app_data(ctx, NULL);
		return (0);
	}
#endif
	return (1);
}
static int
ssh1_3des_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src, u_int len)
{
	struct ssh1_3des_ctx *c;

	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
		error("ssh1_3des_cbc: no context");
		return (0);
	}
#ifdef SSH_OLD_EVP
	EVP_Cipher(&c->k1, dest, (u_char *)src, len);
	EVP_Cipher(&c->k2, dest, dest, len);
	EVP_Cipher(&c->k3, dest, dest, len);
#else
	if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 ||
	    EVP_Cipher(&c->k2, dest, dest, len) == 0 ||
	    EVP_Cipher(&c->k3, dest, dest, len) == 0)
		return (0);
#endif
	return (1);
}
static int
ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
{
	struct ssh1_3des_ctx *c;

	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
		memset(c, 0, sizeof(*c));
		xfree(c);
		EVP_CIPHER_CTX_set_app_data(ctx, NULL);
	}
	return (1);
}
static EVP_CIPHER *
evp_ssh1_3des(void)
{
	static EVP_CIPHER ssh1_3des;

	memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
	ssh1_3des.nid = NID_undef;
	ssh1_3des.block_size = 8;
	ssh1_3des.iv_len = 0;
	ssh1_3des.key_len = 16;
	ssh1_3des.init = ssh1_3des_init;
	ssh1_3des.cleanup = ssh1_3des_cleanup;
	ssh1_3des.do_cipher = ssh1_3des_cbc;
#ifndef SSH_OLD_EVP
	ssh1_3des.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH;
#endif
	return (&ssh1_3des);
}

/*
 * SSH1 uses a variation on Blowfish, all bytes must be swapped before
 * and after encryption/decryption. Thus the swap_bytes stuff (yuk).
 */
static void
swap_bytes(const u_char *src, u_char *dst, int n)
{
	u_char c[4];

	/* Process 4 bytes every lap. */
	for (n = n / 4; n > 0; n--) {
		c[3] = *src++;
		c[2] = *src++;
		c[1] = *src++;
		c[0] = *src++;

		*dst++ = c[0];
		*dst++ = c[1];
		*dst++ = c[2];
		*dst++ = c[3];
	}
}
static int (*orig_bf)(EVP_CIPHER_CTX *, u_char *, const u_char *, u_int) = NULL;
static int
bf_ssh1_cipher(EVP_CIPHER_CTX *ctx, u_char *out, const u_char *in, u_int len)
{
	int ret;

	swap_bytes(in, out, len);
	ret = (*orig_bf)(ctx, out, out, len);
	swap_bytes(out, out, len);
	return (ret);
}
static EVP_CIPHER *
evp_ssh1_bf(void)
{
	static EVP_CIPHER ssh1_bf;

	memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER));
	orig_bf = ssh1_bf.do_cipher;
	ssh1_bf.nid = NID_undef;
	ssh1_bf.do_cipher = bf_ssh1_cipher;
	ssh1_bf.key_len = 32;
	return (&ssh1_bf);
}

/* RIJNDAEL */
#define RIJNDAEL_BLOCKSIZE 16
struct ssh_rijndael_ctx
{
	rijndael_ctx	r_ctx;
	u_char		r_iv[RIJNDAEL_BLOCKSIZE];
};

static int
ssh_rijndael_init(EVP_CIPHER_CTX *ctx, const u_char *key, const u_char *iv,
    int enc)
{
	struct ssh_rijndael_ctx *c;

	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
		c = xmalloc(sizeof(*c));
		EVP_CIPHER_CTX_set_app_data(ctx, c);
	}
	if (key != NULL) {
		if (enc == -1)
			enc = ctx->encrypt;
		rijndael_set_key(&c->r_ctx, (u_char *)key,
		    8*EVP_CIPHER_CTX_key_length(ctx), enc);
	}
	if (iv != NULL)
		memcpy(c->r_iv, iv, RIJNDAEL_BLOCKSIZE);
	return (1);
}
static int
ssh_rijndael_cbc(EVP_CIPHER_CTX *ctx, u_char *dest, const u_char *src,
    u_int len)
{
	struct ssh_rijndael_ctx *c;
	u_char buf[RIJNDAEL_BLOCKSIZE];
	u_char *cprev, *cnow, *plain, *ivp;
	int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;

	if (len == 0)
		return (1);
	if (len % RIJNDAEL_BLOCKSIZE)
		fatal("ssh_rijndael_cbc: bad len %d", len);
	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
		error("ssh_rijndael_cbc: no context");
		return (0);
	}
	if (ctx->encrypt) {
		cnow  = dest;
		plain = (u_char *)src;
		cprev = c->r_iv;
		for (i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE,
		    cnow+=RIJNDAEL_BLOCKSIZE) {
			for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
				buf[j] = plain[j] ^ cprev[j];
			rijndael_encrypt(&c->r_ctx, buf, cnow);
			cprev = cnow;
		}
		memcpy(c->r_iv, cprev, RIJNDAEL_BLOCKSIZE);
	} else {
		cnow  = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE);
		plain = dest+len-RIJNDAEL_BLOCKSIZE;

		memcpy(buf, cnow, RIJNDAEL_BLOCKSIZE);
		for (i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE,
		    plain-=RIJNDAEL_BLOCKSIZE) {
			rijndael_decrypt(&c->r_ctx, cnow, plain);
			ivp = (i == 1) ? c->r_iv : cnow-RIJNDAEL_BLOCKSIZE;
			for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
				plain[j] ^= ivp[j];
		}
		memcpy(c->r_iv, buf, RIJNDAEL_BLOCKSIZE);
	}
	return (1);
}
static int
ssh_rijndael_cleanup(EVP_CIPHER_CTX *ctx)
{
	struct ssh_rijndael_ctx *c;

	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
		memset(c, 0, sizeof(*c));
		xfree(c);
		EVP_CIPHER_CTX_set_app_data(ctx, NULL);
	}
	return (1);
}
static EVP_CIPHER *
evp_rijndael(void)
{
	static EVP_CIPHER rijndal_cbc;

	memset(&rijndal_cbc, 0, sizeof(EVP_CIPHER));
	rijndal_cbc.nid = NID_undef;
	rijndal_cbc.block_size = RIJNDAEL_BLOCKSIZE;
	rijndal_cbc.iv_len = RIJNDAEL_BLOCKSIZE;
	rijndal_cbc.key_len = 16;
	rijndal_cbc.init = ssh_rijndael_init;
	rijndal_cbc.cleanup = ssh_rijndael_cleanup;
	rijndal_cbc.do_cipher = ssh_rijndael_cbc;
#ifndef SSH_OLD_EVP
	rijndal_cbc.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH |
	    EVP_CIPH_ALWAYS_CALL_INIT;
#endif
	return (&rijndal_cbc);
}
Commit	Line	Data
8efc0c15	1	/*
5260325f	2	* Author: Tatu Ylonen <ylo@cs.hut.fi>
5260325f	3	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5260325f	4	* All rights reserved
6ae2364d	5	*
bcbf86ec	6	* As far as I am concerned, the code I have written for this software
	7	* can be used freely for any purpose. Any derived versions of this
	8	* software must be clearly marked as such, and if the derived work is
	9	* incompatible with the protocol description in the RFC file, it must be
	10	* called by a name other than "ssh" or "Secure Shell".
	11	*
	12	*
	13	* Copyright (c) 1999 Niels Provos. All rights reserved.
a96070d4	14	* Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
bcbf86ec	15	*
	16	* Redistribution and use in source and binary forms, with or without
	17	* modification, are permitted provided that the following conditions
	18	* are met:
	19	* 1. Redistributions of source code must retain the above copyright
	20	* notice, this list of conditions and the following disclaimer.
	21	* 2. Redistributions in binary form must reproduce the above copyright
	22	* notice, this list of conditions and the following disclaimer in the
	23	* documentation and/or other materials provided with the distribution.
6ae2364d	24	*
bcbf86ec	25	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
	26	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	27	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
	28	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
	29	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
	30	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	31	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	32	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	33	* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
	34	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
5260325f	35	*/
8efc0c15	36
8efc0c15	37	#include "includes.h"
70fc1609	38	RCSID("$OpenBSD: cipher.c,v 1.52 2002/02/18 13:05:32 markus Exp $");
8efc0c15	39
a8be9f80	40	#include "xmalloc.h"
42f11eb2	41	#include "log.h"
42f11eb2	42	#include "cipher.h"
8efc0c15	43
8efc0c15	44	#include <openssl/md5.h>
70fc1609	45	#include "rijndael.h"
70fc1609	46
a068d86f	47	#if OPENSSL_VERSION_NUMBER < 0x00906000L
	48	#define SSH_OLD_EVP
	49	#define EVP_CIPHER_CTX_get_app_data(e) ((e)->app_data)
	50	#endif
	51
70fc1609	52	static EVP_CIPHER *evp_ssh1_3des(void);
	53	static EVP_CIPHER *evp_ssh1_bf(void);
	54	static EVP_CIPHER *evp_rijndael(void);
8efc0c15	55
3ee832e5	56	struct Cipher {
	57	char *name;
	58	int number; /* for ssh1 only */
	59	u_int block_size;
	60	u_int key_len;
70fc1609	61	EVP_CIPHER (evptype)(void);
	62	} ciphers[] = {
	63	{ "none", SSH_CIPHER_NONE, 8, 0, EVP_enc_null },
	64	{ "des", SSH_CIPHER_DES, 8, 8, EVP_des_cbc },
	65	{ "3des", SSH_CIPHER_3DES, 8, 16, evp_ssh1_3des },
	66	{ "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, evp_ssh1_bf },
	67
	68	{ "3des-cbc", SSH_CIPHER_SSH2, 8, 24, EVP_des_ede3_cbc },
	69	{ "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_bf_cbc },
	70	{ "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_cast5_cbc },
	71	{ "arcfour", SSH_CIPHER_SSH2, 8, 16, EVP_rc4 },
	72	{ "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, evp_rijndael },
	73	{ "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, evp_rijndael },
	74	{ "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
	75
	76	{ NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL }
94ec8c6b	77	};
	78
	79	/--/
	80
70fc1609	81	u_int
3ee832e5	82	cipher_blocksize(Cipher *c)
	83	{
	84	return (c->block_size);
	85	}
70fc1609	86	u_int
3ee832e5	87	cipher_keylen(Cipher *c)
	88	{
	89	return (c->key_len);
	90	}
	91
1e3b8b07	92	u_int
94ec8c6b	93	cipher_mask_ssh1(int client)
8ce64345	94	{
1e3b8b07	95	u_int mask = 0;
184eed6a	96	mask \|= 1 << SSH_CIPHER_3DES; /* Mandatory */
94ec8c6b	97	mask \|= 1 << SSH_CIPHER_BLOWFISH;
	98	if (client) {
	99	mask \|= 1 << SSH_CIPHER_DES;
	100	}
5260325f	101	return mask;
8efc0c15	102	}
94ec8c6b	103
	104	Cipher *
	105	cipher_by_name(const char *name)
8ce64345	106	{
94ec8c6b	107	Cipher *c;
	108	for (c = ciphers; c->name != NULL; c++)
	109	if (strcasecmp(c->name, name) == 0)
	110	return c;
	111	return NULL;
8ce64345	112	}
8efc0c15	113
94ec8c6b	114	Cipher *
94ec8c6b	115	cipher_by_number(int id)
8efc0c15	116	{
94ec8c6b	117	Cipher *c;
	118	for (c = ciphers; c->name != NULL; c++)
	119	if (c->number == id)
	120	return c;
	121	return NULL;
8efc0c15	122	}
8efc0c15	123
a8be9f80	124	#define CIPHER_SEP ","
	125	int
	126	ciphers_valid(const char *names)
	127	{
94ec8c6b	128	Cipher *c;
089fbbd2	129	char ciphers, cp;
a8be9f80	130	char *p;
a8be9f80	131
71276795	132	if (names == NULL \|\| strcmp(names, "") == 0)
a8be9f80	133	return 0;
089fbbd2	134	ciphers = cp = xstrdup(names);
94ec8c6b	135	for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
184eed6a	136	(p = strsep(&cp, CIPHER_SEP))) {
94ec8c6b	137	c = cipher_by_name(p);
	138	if (c == NULL \|\| c->number != SSH_CIPHER_SSH2) {
	139	debug("bad cipher %s [%s]", p, names);
a8be9f80	140	xfree(ciphers);
a8be9f80	141	return 0;
94ec8c6b	142	} else {
33de75a3	143	debug3("cipher ok: %s [%s]", p, names);
a8be9f80	144	}
a8be9f80	145	}
33de75a3	146	debug3("ciphers ok: [%s]", names);
a8be9f80	147	xfree(ciphers);
	148	return 1;
	149	}
	150
aa3378df	151	/*
	152	* Parses the name of the cipher. Returns the number of the corresponding
	153	* cipher, or -1 on error.
	154	*/
8efc0c15	155
	156	int
	157	cipher_number(const char *name)
	158	{
94ec8c6b	159	Cipher *c;
71276795	160	if (name == NULL)
71276795	161	return -1;
94ec8c6b	162	c = cipher_by_name(name);
	163	return (c==NULL) ? -1 : c->number;
	164	}
	165
	166	char *
	167	cipher_name(int id)
	168	{
	169	Cipher *c = cipher_by_number(id);
	170	return (c==NULL) ? "<unknown>" : c->name;
	171	}
	172
	173	void
70fc1609	174	cipher_init(CipherContext cc, Cipher cipher,
	175	const u_char key, u_int keylen, const u_char iv, u_int ivlen,
	176	int encrypt)
94ec8c6b	177	{
70fc1609	178	static int dowarn = 1;
a068d86f	179	#ifdef SSH_OLD_EVP
	180	EVP_CIPHER *type;
	181	#else
70fc1609	182	const EVP_CIPHER *type;
a068d86f	183	#endif
70fc1609	184	int klen;
	185
	186	if (cipher->number == SSH_CIPHER_DES) {
	187	if (dowarn) {
	188	error("Warning: use of DES is strongly discouraged "
	189	"due to cryptographic weaknesses");
	190	dowarn = 0;
	191	}
	192	if (keylen > 8)
	193	keylen = 8;
	194	}
	195	cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
	196
94ec8c6b	197	if (keylen < cipher->key_len)
	198	fatal("cipher_init: key length %d is insufficient for %s.",
	199	keylen, cipher->name);
	200	if (iv != NULL && ivlen < cipher->block_size)
	201	fatal("cipher_init: iv length %d is insufficient for %s.",
	202	ivlen, cipher->name);
	203	cc->cipher = cipher;
70fc1609	204
	205	type = (*cipher->evptype)();
	206
	207	EVP_CIPHER_CTX_init(&cc->evp);
a068d86f	208	#ifdef SSH_OLD_EVP
	209	if (type->key_len > 0 && type->key_len != keylen) {
	210	debug("cipher_init: set keylen (%d -> %d)",
	211	type->key_len, keylen);
	212	type->key_len = keylen;
	213	}
	214	EVP_CipherInit(&cc->evp, type, (u_char )key, (u_char )iv,
	215	(encrypt == CIPHER_ENCRYPT));
	216	#else
70fc1609	217	if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
	218	(encrypt == CIPHER_ENCRYPT)) == 0)
	219	fatal("cipher_init: EVP_CipherInit failed for %s",
	220	cipher->name);
	221	klen = EVP_CIPHER_CTX_key_length(&cc->evp);
	222	if (klen > 0 && keylen != klen) {
	223	debug("cipher_init: set keylen (%d -> %d)", klen, keylen);
	224	if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
	225	fatal("cipher_init: set keylen failed (%d -> %d)",
	226	klen, keylen);
	227	}
	228	if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
	229	fatal("cipher_init: EVP_CipherInit: set key failed for %s",
	230	cipher->name);
a068d86f	231	#endif
94ec8c6b	232	}
	233
	234	void
3ee832e5	235	cipher_crypt(CipherContext cc, u_char dest, const u_char *src, u_int len)
94ec8c6b	236	{
	237	if (len % cc->cipher->block_size)
	238	fatal("cipher_encrypt: bad plaintext length %d", len);
a068d86f	239	#ifdef SSH_OLD_EVP
	240	EVP_Cipher(&cc->evp, dest, (u_char *)src, len);
	241	#else
70fc1609	242	if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
70fc1609	243	fatal("evp_crypt: EVP_Cipher failed");
a068d86f	244	#endif
94ec8c6b	245	}
	246
	247	void
3ee832e5	248	cipher_cleanup(CipherContext *cc)
94ec8c6b	249	{
a068d86f	250	#ifdef SSH_OLD_EVP
	251	EVP_CIPHER_CTX_cleanup(&cc->evp);
	252	#else
70fc1609	253	if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
70fc1609	254	error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
a068d86f	255	#endif
8efc0c15	256	}
8efc0c15	257
aa3378df	258	/*
	259	* Selects the cipher, and keys if by computing the MD5 checksum of the
	260	* passphrase and using the resulting 16 bytes as the key.
	261	*/
8efc0c15	262
6ae2364d	263	void
94ec8c6b	264	cipher_set_key_string(CipherContext cc, Cipher cipher,
3ee832e5	265	const char *passphrase, int encrypt)
8efc0c15	266	{
5260325f	267	MD5_CTX md;
1e3b8b07	268	u_char digest[16];
5260325f	269
5260325f	270	MD5_Init(&md);
94ec8c6b	271	MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
5260325f	272	MD5_Final(digest, &md);
5260325f	273
3ee832e5	274	cipher_init(cc, cipher, digest, 16, NULL, 0, encrypt);
5260325f	275
	276	memset(digest, 0, sizeof(digest));
	277	memset(&md, 0, sizeof(md));
8efc0c15	278	}
70fc1609	279
	280	/* Implementations for other non-EVP ciphers */
	281
	282	/*
	283	* This is used by SSH1:
	284	*
	285	* What kind of triple DES are these 2 routines?
	286	*
	287	* Why is there a redundant initialization vector?
	288	*
	289	* If only iv3 was used, then, this would till effect have been
	290	* outer-cbc. However, there is also a private iv1 == iv2 which
	291	* perhaps makes differential analysis easier. On the other hand, the
	292	* private iv1 probably makes the CRC-32 attack ineffective. This is a
	293	* result of that there is no longer any known iv1 to use when
	294	* choosing the X block.
	295	*/
	296	struct ssh1_3des_ctx
	297	{
	298	EVP_CIPHER_CTX k1, k2, k3;
	299	};
	300	static int
	301	ssh1_3des_init(EVP_CIPHER_CTX ctx, const u_char key, const u_char *iv,
	302	int enc)
	303	{
	304	struct ssh1_3des_ctx *c;
	305	u_char k1, k2, *k3;
	306
	307	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
	308	c = xmalloc(sizeof(*c));
	309	EVP_CIPHER_CTX_set_app_data(ctx, c);
	310	}
	311	if (key == NULL)
	312	return (1);
	313	if (enc == -1)
	314	enc = ctx->encrypt;
	315	k1 = k2 = k3 = (u_char *) key;
	316	k2 += 8;
	317	if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) {
	318	if (enc)
	319	k3 += 16;
	320	else
	321	k1 += 16;
	322	}
	323	EVP_CIPHER_CTX_init(&c->k1);
	324	EVP_CIPHER_CTX_init(&c->k2);
	325	EVP_CIPHER_CTX_init(&c->k3);
a068d86f	326	#ifdef SSH_OLD_EVP
	327	EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc);
	328	EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc);
	329	EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc);
	330	#else
70fc1609	331	if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 \|\|
	332	EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 \|\|
	333	EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
	334	memset(c, 0, sizeof(*c));
	335	xfree(c);
	336	EVP_CIPHER_CTX_set_app_data(ctx, NULL);
	337	return (0);
	338	}
a068d86f	339	#endif
70fc1609	340	return (1);
	341	}
	342	static int
	343	ssh1_3des_cbc(EVP_CIPHER_CTX ctx, u_char dest, const u_char *src, u_int len)
	344	{
	345	struct ssh1_3des_ctx *c;
	346
	347	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
	348	error("ssh1_3des_cbc: no context");
	349	return (0);
	350	}
a068d86f	351	#ifdef SSH_OLD_EVP
	352	EVP_Cipher(&c->k1, dest, (u_char *)src, len);
	353	EVP_Cipher(&c->k2, dest, dest, len);
	354	EVP_Cipher(&c->k3, dest, dest, len);
	355	#else
70fc1609	356	if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 \|\|
	357	EVP_Cipher(&c->k2, dest, dest, len) == 0 \|\|
	358	EVP_Cipher(&c->k3, dest, dest, len) == 0)
	359	return (0);
a068d86f	360	#endif
70fc1609	361	return (1);
	362	}
	363	static int
	364	ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
	365	{
	366	struct ssh1_3des_ctx *c;
	367
	368	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
	369	memset(c, 0, sizeof(*c));
	370	xfree(c);
	371	EVP_CIPHER_CTX_set_app_data(ctx, NULL);
	372	}
	373	return (1);
	374	}
	375	static EVP_CIPHER *
	376	evp_ssh1_3des(void)
	377	{
	378	static EVP_CIPHER ssh1_3des;
	379
	380	memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
	381	ssh1_3des.nid = NID_undef;
	382	ssh1_3des.block_size = 8;
	383	ssh1_3des.iv_len = 0;
	384	ssh1_3des.key_len = 16;
	385	ssh1_3des.init = ssh1_3des_init;
	386	ssh1_3des.cleanup = ssh1_3des_cleanup;
	387	ssh1_3des.do_cipher = ssh1_3des_cbc;
a068d86f	388	#ifndef SSH_OLD_EVP
70fc1609	389	ssh1_3des.flags = EVP_CIPH_CBC_MODE \| EVP_CIPH_VARIABLE_LENGTH;
a068d86f	390	#endif
70fc1609	391	return (&ssh1_3des);
	392	}
	393
	394	/*
	395	* SSH1 uses a variation on Blowfish, all bytes must be swapped before
	396	* and after encryption/decryption. Thus the swap_bytes stuff (yuk).
	397	*/
	398	static void
	399	swap_bytes(const u_char src, u_char dst, int n)
	400	{
	401	u_char c[4];
	402
	403	/* Process 4 bytes every lap. */
	404	for (n = n / 4; n > 0; n--) {
	405	c[3] = *src++;
	406	c[2] = *src++;
	407	c[1] = *src++;
	408	c[0] = *src++;
	409
	410	*dst++ = c[0];
	411	*dst++ = c[1];
	412	*dst++ = c[2];
	413	*dst++ = c[3];
	414	}
	415	}
	416	static int (orig_bf)(EVP_CIPHER_CTX , u_char , const u_char , u_int) = NULL;
	417	static int
	418	bf_ssh1_cipher(EVP_CIPHER_CTX ctx, u_char out, const u_char *in, u_int len)
	419	{
	420	int ret;
	421
	422	swap_bytes(in, out, len);
	423	ret = (*orig_bf)(ctx, out, out, len);
	424	swap_bytes(out, out, len);
	425	return (ret);
	426	}
	427	static EVP_CIPHER *
	428	evp_ssh1_bf(void)
	429	{
	430	static EVP_CIPHER ssh1_bf;
	431
	432	memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER));
	433	orig_bf = ssh1_bf.do_cipher;
	434	ssh1_bf.nid = NID_undef;
	435	ssh1_bf.do_cipher = bf_ssh1_cipher;
	436	ssh1_bf.key_len = 32;
	437	return (&ssh1_bf);
	438	}
	439
	440	/* RIJNDAEL */
	441	#define RIJNDAEL_BLOCKSIZE 16
	442	struct ssh_rijndael_ctx
	443	{
	444	rijndael_ctx r_ctx;
	445	u_char r_iv[RIJNDAEL_BLOCKSIZE];
	446	};
	447
	448	static int
	449	ssh_rijndael_init(EVP_CIPHER_CTX ctx, const u_char key, const u_char *iv,
	450	int enc)
	451	{
	452	struct ssh_rijndael_ctx *c;
	453
	454	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
455	c = xmalloc(sizeof(*c));
456	EVP_CIPHER_CTX_set_app_data(ctx, c);
457	}
458	if (key != NULL) {
459	if (enc == -1)
460	enc = ctx->encrypt;
461	rijndael_set_key(&c->r_ctx, (u_char *)key,
462	8*EVP_CIPHER_CTX_key_length(ctx), enc);
463	}
464	if (iv != NULL)
465	memcpy(c->r_iv, iv, RIJNDAEL_BLOCKSIZE);
466	return (1);
467	}
468	static int
469	ssh_rijndael_cbc(EVP_CIPHER_CTX ctx, u_char dest, const u_char *src,
470	u_int len)
471	{
472	struct ssh_rijndael_ctx *c;
473	u_char buf[RIJNDAEL_BLOCKSIZE];
474	u_char cprev, cnow, plain, ivp;
475	int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;
476
477	if (len == 0)
478	return (1);
479	if (len % RIJNDAEL_BLOCKSIZE)
480	fatal("ssh_rijndael_cbc: bad len %d", len);
481	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
482	error("ssh_rijndael_cbc: no context");
483	return (0);
484	}
485	if (ctx->encrypt) {
486	cnow = dest;
487	plain = (u_char *)src;
488	cprev = c->r_iv;
489	for (i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE,
490	cnow+=RIJNDAEL_BLOCKSIZE) {
491	for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
492	buf[j] = plain[j] ^ cprev[j];
493	rijndael_encrypt(&c->r_ctx, buf, cnow);
494	cprev = cnow;
495	}
496	memcpy(c->r_iv, cprev, RIJNDAEL_BLOCKSIZE);
497	} else {
498	cnow = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE);
499	plain = dest+len-RIJNDAEL_BLOCKSIZE;
500
501	memcpy(buf, cnow, RIJNDAEL_BLOCKSIZE);
502	for (i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE,
503	plain-=RIJNDAEL_BLOCKSIZE) {
504	rijndael_decrypt(&c->r_ctx, cnow, plain);
505	ivp = (i == 1) ? c->r_iv : cnow-RIJNDAEL_BLOCKSIZE;
506	for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
507	plain[j] ^= ivp[j];
508	}
509	memcpy(c->r_iv, buf, RIJNDAEL_BLOCKSIZE);
510	}
511	return (1);
512	}
513	static int
514	ssh_rijndael_cleanup(EVP_CIPHER_CTX *ctx)
515	{
516	struct ssh_rijndael_ctx *c;
517
518	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
519	memset(c, 0, sizeof(*c));
520	xfree(c);
521	EVP_CIPHER_CTX_set_app_data(ctx, NULL);
522	}
523	return (1);
524	}
525	static EVP_CIPHER *
526	evp_rijndael(void)
527	{
528	static EVP_CIPHER rijndal_cbc;
529
530	memset(&rijndal_cbc, 0, sizeof(EVP_CIPHER));
531	rijndal_cbc.nid = NID_undef;
532	rijndal_cbc.block_size = RIJNDAEL_BLOCKSIZE;
533	rijndal_cbc.iv_len = RIJNDAEL_BLOCKSIZE;
534	rijndal_cbc.key_len = 16;
535	rijndal_cbc.init = ssh_rijndael_init;
536	rijndal_cbc.cleanup = ssh_rijndael_cleanup;
537	rijndal_cbc.do_cipher = ssh_rijndael_cbc;
a068d86f	538	#ifndef SSH_OLD_EVP
70fc1609	539	rijndal_cbc.flags = EVP_CIPH_CBC_MODE \| EVP_CIPH_VARIABLE_LENGTH \|
70fc1609	540	EVP_CIPH_ALWAYS_CALL_INIT;
a068d86f	541	#endif
70fc1609	542	return (&rijndal_cbc);
70fc1609	543	}