[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"

#if OPENSSL_VERSION_NUMBER <= 0x0090600fL
#define EVP_CIPHER_CTX_get_app_data(e)          ((e)->app_data)
#endif
 
#include <openssl/md5.h>
#include "rijndael.h"

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;
	const EVP_CIPHER *type;
	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);
#if OPENSSL_VERSION_NUMBER > 0x0090600fL
	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);
#else
	EVP_CipherInit(&cc->evp, type, (u_char *)key, (u_char *)iv,
	    (encrypt == CIPHER_ENCRYPT));
#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);
#if OPENSSL_VERSION_NUMBER > 0x0090600fL
	if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
		fatal("evp_crypt: EVP_Cipher failed");
#else
	EVP_Cipher(&cc->evp, dest, (u_char *)src, len);
#endif
}

void
cipher_cleanup(CipherContext *cc)
{
#if OPENSSL_VERSION_NUMBER > 0x0090600fL
	if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
		error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
#else
	EVP_CIPHER_CTX_cleanup(&cc->evp);
#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);
#if OPENSSL_VERSION_NUMBER > 0x0090600fL
	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);
	}
#else
	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);
#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);
	}
#if OPENSSL_VERSION_NUMBER > 0x0090600fL
	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);
#else
	EVP_Cipher(&c->k1, dest, (u_char *)src, len);
	EVP_Cipher(&c->k2, dest, dest, len);
	EVP_Cipher(&c->k3, dest, dest, len);
#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;
#if OPENSSL_VERSION_NUMBER > 0x0090600fL
	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;
#if OPENSSL_VERSION_NUMBER > 0x0090600fL
	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
492a3893	44	#if OPENSSL_VERSION_NUMBER <= 0x0090600fL
	45	#define EVP_CIPHER_CTX_get_app_data(e) ((e)->app_data)
	46	#endif
	47
8efc0c15	48	#include <openssl/md5.h>
70fc1609	49	#include "rijndael.h"
	50
	51	static EVP_CIPHER *evp_ssh1_3des(void);
	52	static EVP_CIPHER *evp_ssh1_bf(void);
	53	static EVP_CIPHER *evp_rijndael(void);
8efc0c15	54
3ee832e5	55	struct Cipher {
	56	char *name;
	57	int number; /* for ssh1 only */
	58	u_int block_size;
	59	u_int key_len;
70fc1609	60	EVP_CIPHER (evptype)(void);
	61	} ciphers[] = {
	62	{ "none", SSH_CIPHER_NONE, 8, 0, EVP_enc_null },
	63	{ "des", SSH_CIPHER_DES, 8, 8, EVP_des_cbc },
	64	{ "3des", SSH_CIPHER_3DES, 8, 16, evp_ssh1_3des },
	65	{ "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, evp_ssh1_bf },
	66
	67	{ "3des-cbc", SSH_CIPHER_SSH2, 8, 24, EVP_des_ede3_cbc },
	68	{ "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_bf_cbc },
	69	{ "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, EVP_cast5_cbc },
	70	{ "arcfour", SSH_CIPHER_SSH2, 8, 16, EVP_rc4 },
	71	{ "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, evp_rijndael },
	72	{ "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, evp_rijndael },
	73	{ "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
	74
	75	{ NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL }
94ec8c6b	76	};
	77
	78	/--/
	79
70fc1609	80	u_int
3ee832e5	81	cipher_blocksize(Cipher *c)
	82	{
	83	return (c->block_size);
	84	}
70fc1609	85	u_int
3ee832e5	86	cipher_keylen(Cipher *c)
	87	{
	88	return (c->key_len);
	89	}
	90
1e3b8b07	91	u_int
94ec8c6b	92	cipher_mask_ssh1(int client)
8ce64345	93	{
1e3b8b07	94	u_int mask = 0;
184eed6a	95	mask \|= 1 << SSH_CIPHER_3DES; /* Mandatory */
94ec8c6b	96	mask \|= 1 << SSH_CIPHER_BLOWFISH;
	97	if (client) {
	98	mask \|= 1 << SSH_CIPHER_DES;
	99	}
5260325f	100	return mask;
8efc0c15	101	}
94ec8c6b	102
	103	Cipher *
	104	cipher_by_name(const char *name)
8ce64345	105	{
94ec8c6b	106	Cipher *c;
	107	for (c = ciphers; c->name != NULL; c++)
	108	if (strcasecmp(c->name, name) == 0)
	109	return c;
	110	return NULL;
8ce64345	111	}
8efc0c15	112
94ec8c6b	113	Cipher *
94ec8c6b	114	cipher_by_number(int id)
8efc0c15	115	{
94ec8c6b	116	Cipher *c;
	117	for (c = ciphers; c->name != NULL; c++)
	118	if (c->number == id)
	119	return c;
	120	return NULL;
8efc0c15	121	}
8efc0c15	122
a8be9f80	123	#define CIPHER_SEP ","
	124	int
	125	ciphers_valid(const char *names)
	126	{
94ec8c6b	127	Cipher *c;
089fbbd2	128	char ciphers, cp;
a8be9f80	129	char *p;
a8be9f80	130
71276795	131	if (names == NULL \|\| strcmp(names, "") == 0)
a8be9f80	132	return 0;
089fbbd2	133	ciphers = cp = xstrdup(names);
94ec8c6b	134	for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
184eed6a	135	(p = strsep(&cp, CIPHER_SEP))) {
94ec8c6b	136	c = cipher_by_name(p);
	137	if (c == NULL \|\| c->number != SSH_CIPHER_SSH2) {
	138	debug("bad cipher %s [%s]", p, names);
a8be9f80	139	xfree(ciphers);
a8be9f80	140	return 0;
94ec8c6b	141	} else {
33de75a3	142	debug3("cipher ok: %s [%s]", p, names);
a8be9f80	143	}
a8be9f80	144	}
33de75a3	145	debug3("ciphers ok: [%s]", names);
a8be9f80	146	xfree(ciphers);
	147	return 1;
	148	}
	149
aa3378df	150	/*
	151	* Parses the name of the cipher. Returns the number of the corresponding
	152	* cipher, or -1 on error.
	153	*/
8efc0c15	154
	155	int
	156	cipher_number(const char *name)
	157	{
94ec8c6b	158	Cipher *c;
71276795	159	if (name == NULL)
71276795	160	return -1;
94ec8c6b	161	c = cipher_by_name(name);
	162	return (c==NULL) ? -1 : c->number;
	163	}
	164
	165	char *
	166	cipher_name(int id)
	167	{
	168	Cipher *c = cipher_by_number(id);
	169	return (c==NULL) ? "<unknown>" : c->name;
	170	}
	171
	172	void
70fc1609	173	cipher_init(CipherContext cc, Cipher cipher,
	174	const u_char key, u_int keylen, const u_char iv, u_int ivlen,
	175	int encrypt)
94ec8c6b	176	{
70fc1609	177	static int dowarn = 1;
	178	const EVP_CIPHER *type;
	179	int klen;
	180
	181	if (cipher->number == SSH_CIPHER_DES) {
	182	if (dowarn) {
	183	error("Warning: use of DES is strongly discouraged "
	184	"due to cryptographic weaknesses");
	185	dowarn = 0;
	186	}
	187	if (keylen > 8)
	188	keylen = 8;
	189	}
	190	cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
	191
94ec8c6b	192	if (keylen < cipher->key_len)
	193	fatal("cipher_init: key length %d is insufficient for %s.",
	194	keylen, cipher->name);
	195	if (iv != NULL && ivlen < cipher->block_size)
	196	fatal("cipher_init: iv length %d is insufficient for %s.",
	197	ivlen, cipher->name);
	198	cc->cipher = cipher;
70fc1609	199
	200	type = (*cipher->evptype)();
	201
	202	EVP_CIPHER_CTX_init(&cc->evp);
492a3893	203	#if OPENSSL_VERSION_NUMBER > 0x0090600fL
70fc1609	204	if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
	205	(encrypt == CIPHER_ENCRYPT)) == 0)
	206	fatal("cipher_init: EVP_CipherInit failed for %s",
	207	cipher->name);
	208	klen = EVP_CIPHER_CTX_key_length(&cc->evp);
	209	if (klen > 0 && keylen != klen) {
	210	debug("cipher_init: set keylen (%d -> %d)", klen, keylen);
	211	if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
	212	fatal("cipher_init: set keylen failed (%d -> %d)",
	213	klen, keylen);
	214	}
	215	if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
	216	fatal("cipher_init: EVP_CipherInit: set key failed for %s",
	217	cipher->name);
492a3893	218	#else
	219	EVP_CipherInit(&cc->evp, type, (u_char )key, (u_char )iv,
	220	(encrypt == CIPHER_ENCRYPT));
	221	#endif
94ec8c6b	222	}
	223
	224	void
3ee832e5	225	cipher_crypt(CipherContext cc, u_char dest, const u_char *src, u_int len)
94ec8c6b	226	{
	227	if (len % cc->cipher->block_size)
	228	fatal("cipher_encrypt: bad plaintext length %d", len);
492a3893	229	#if OPENSSL_VERSION_NUMBER > 0x0090600fL
70fc1609	230	if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
70fc1609	231	fatal("evp_crypt: EVP_Cipher failed");
492a3893	232	#else
	233	EVP_Cipher(&cc->evp, dest, (u_char *)src, len);
	234	#endif
94ec8c6b	235	}
	236
	237	void
3ee832e5	238	cipher_cleanup(CipherContext *cc)
94ec8c6b	239	{
492a3893	240	#if OPENSSL_VERSION_NUMBER > 0x0090600fL
70fc1609	241	if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
70fc1609	242	error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
492a3893	243	#else
	244	EVP_CIPHER_CTX_cleanup(&cc->evp);
	245	#endif
8efc0c15	246	}
8efc0c15	247
aa3378df	248	/*
	249	* Selects the cipher, and keys if by computing the MD5 checksum of the
	250	* passphrase and using the resulting 16 bytes as the key.
	251	*/
8efc0c15	252
6ae2364d	253	void
94ec8c6b	254	cipher_set_key_string(CipherContext cc, Cipher cipher,
3ee832e5	255	const char *passphrase, int encrypt)
8efc0c15	256	{
5260325f	257	MD5_CTX md;
1e3b8b07	258	u_char digest[16];
5260325f	259
5260325f	260	MD5_Init(&md);
94ec8c6b	261	MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
5260325f	262	MD5_Final(digest, &md);
5260325f	263
3ee832e5	264	cipher_init(cc, cipher, digest, 16, NULL, 0, encrypt);
5260325f	265
	266	memset(digest, 0, sizeof(digest));
	267	memset(&md, 0, sizeof(md));
8efc0c15	268	}
70fc1609	269
	270	/* Implementations for other non-EVP ciphers */
	271
	272	/*
	273	* This is used by SSH1:
	274	*
	275	* What kind of triple DES are these 2 routines?
	276	*
	277	* Why is there a redundant initialization vector?
	278	*
	279	* If only iv3 was used, then, this would till effect have been
	280	* outer-cbc. However, there is also a private iv1 == iv2 which
	281	* perhaps makes differential analysis easier. On the other hand, the
	282	* private iv1 probably makes the CRC-32 attack ineffective. This is a
	283	* result of that there is no longer any known iv1 to use when
	284	* choosing the X block.
	285	*/
	286	struct ssh1_3des_ctx
	287	{
	288	EVP_CIPHER_CTX k1, k2, k3;
	289	};
	290	static int
	291	ssh1_3des_init(EVP_CIPHER_CTX ctx, const u_char key, const u_char *iv,
	292	int enc)
	293	{
	294	struct ssh1_3des_ctx *c;
	295	u_char k1, k2, *k3;
	296
	297	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
	298	c = xmalloc(sizeof(*c));
	299	EVP_CIPHER_CTX_set_app_data(ctx, c);
	300	}
	301	if (key == NULL)
	302	return (1);
	303	if (enc == -1)
	304	enc = ctx->encrypt;
	305	k1 = k2 = k3 = (u_char *) key;
	306	k2 += 8;
	307	if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) {
	308	if (enc)
	309	k3 += 16;
	310	else
	311	k1 += 16;
	312	}
	313	EVP_CIPHER_CTX_init(&c->k1);
	314	EVP_CIPHER_CTX_init(&c->k2);
	315	EVP_CIPHER_CTX_init(&c->k3);
492a3893	316	#if OPENSSL_VERSION_NUMBER > 0x0090600fL
70fc1609	317	if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 \|\|
	318	EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 \|\|
	319	EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
	320	memset(c, 0, sizeof(*c));
	321	xfree(c);
	322	EVP_CIPHER_CTX_set_app_data(ctx, NULL);
	323	return (0);
	324	}
492a3893	325	#else
	326	EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc);
	327	EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc);
	328	EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc);
	329	#endif
70fc1609	330	return (1);
	331	}
	332	static int
	333	ssh1_3des_cbc(EVP_CIPHER_CTX ctx, u_char dest, const u_char *src, u_int len)
	334	{
	335	struct ssh1_3des_ctx *c;
	336
	337	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
	338	error("ssh1_3des_cbc: no context");
	339	return (0);
	340	}
492a3893	341	#if OPENSSL_VERSION_NUMBER > 0x0090600fL
70fc1609	342	if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 \|\|
	343	EVP_Cipher(&c->k2, dest, dest, len) == 0 \|\|
	344	EVP_Cipher(&c->k3, dest, dest, len) == 0)
	345	return (0);
492a3893	346	#else
	347	EVP_Cipher(&c->k1, dest, (u_char *)src, len);
	348	EVP_Cipher(&c->k2, dest, dest, len);
	349	EVP_Cipher(&c->k3, dest, dest, len);
	350	#endif
70fc1609	351	return (1);
	352	}
	353	static int
	354	ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
	355	{
	356	struct ssh1_3des_ctx *c;
	357
	358	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
	359	memset(c, 0, sizeof(*c));
	360	xfree(c);
	361	EVP_CIPHER_CTX_set_app_data(ctx, NULL);
	362	}
	363	return (1);
	364	}
	365	static EVP_CIPHER *
	366	evp_ssh1_3des(void)
	367	{
	368	static EVP_CIPHER ssh1_3des;
	369
	370	memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
	371	ssh1_3des.nid = NID_undef;
	372	ssh1_3des.block_size = 8;
	373	ssh1_3des.iv_len = 0;
	374	ssh1_3des.key_len = 16;
	375	ssh1_3des.init = ssh1_3des_init;
	376	ssh1_3des.cleanup = ssh1_3des_cleanup;
	377	ssh1_3des.do_cipher = ssh1_3des_cbc;
492a3893	378	#if OPENSSL_VERSION_NUMBER > 0x0090600fL
70fc1609	379	ssh1_3des.flags = EVP_CIPH_CBC_MODE \| EVP_CIPH_VARIABLE_LENGTH;
492a3893	380	#endif
70fc1609	381	return (&ssh1_3des);
	382	}
	383
	384	/*
	385	* SSH1 uses a variation on Blowfish, all bytes must be swapped before
	386	* and after encryption/decryption. Thus the swap_bytes stuff (yuk).
	387	*/
	388	static void
	389	swap_bytes(const u_char src, u_char dst, int n)
	390	{
	391	u_char c[4];
	392
	393	/* Process 4 bytes every lap. */
	394	for (n = n / 4; n > 0; n--) {
	395	c[3] = *src++;
	396	c[2] = *src++;
	397	c[1] = *src++;
	398	c[0] = *src++;
	399
	400	*dst++ = c[0];
	401	*dst++ = c[1];
	402	*dst++ = c[2];
	403	*dst++ = c[3];
	404	}
	405	}
	406	static int (orig_bf)(EVP_CIPHER_CTX , u_char , const u_char , u_int) = NULL;
	407	static int
	408	bf_ssh1_cipher(EVP_CIPHER_CTX ctx, u_char out, const u_char *in, u_int len)
	409	{
	410	int ret;
	411
	412	swap_bytes(in, out, len);
	413	ret = (*orig_bf)(ctx, out, out, len);
	414	swap_bytes(out, out, len);
	415	return (ret);
	416	}
	417	static EVP_CIPHER *
	418	evp_ssh1_bf(void)
	419	{
	420	static EVP_CIPHER ssh1_bf;
	421
	422	memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER));
	423	orig_bf = ssh1_bf.do_cipher;
	424	ssh1_bf.nid = NID_undef;
	425	ssh1_bf.do_cipher = bf_ssh1_cipher;
	426	ssh1_bf.key_len = 32;
	427	return (&ssh1_bf);
	428	}
	429
	430	/* RIJNDAEL */
	431	#define RIJNDAEL_BLOCKSIZE 16
	432	struct ssh_rijndael_ctx
	433	{
	434	rijndael_ctx r_ctx;
	435	u_char r_iv[RIJNDAEL_BLOCKSIZE];
	436	};
	437
	438	static int
	439	ssh_rijndael_init(EVP_CIPHER_CTX ctx, const u_char key, const u_char *iv,
	440	int enc)
	441	{
	442	struct ssh_rijndael_ctx *c;
	443
	444	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
445	c = xmalloc(sizeof(*c));
446	EVP_CIPHER_CTX_set_app_data(ctx, c);
447	}
448	if (key != NULL) {
449	if (enc == -1)
450	enc = ctx->encrypt;
451	rijndael_set_key(&c->r_ctx, (u_char *)key,
452	8*EVP_CIPHER_CTX_key_length(ctx), enc);
453	}
454	if (iv != NULL)
455	memcpy(c->r_iv, iv, RIJNDAEL_BLOCKSIZE);
456	return (1);
457	}
458	static int
459	ssh_rijndael_cbc(EVP_CIPHER_CTX ctx, u_char dest, const u_char *src,
460	u_int len)
461	{
462	struct ssh_rijndael_ctx *c;
463	u_char buf[RIJNDAEL_BLOCKSIZE];
464	u_char cprev, cnow, plain, ivp;
465	int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;
466
467	if (len == 0)
468	return (1);
469	if (len % RIJNDAEL_BLOCKSIZE)
470	fatal("ssh_rijndael_cbc: bad len %d", len);
471	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
472	error("ssh_rijndael_cbc: no context");
473	return (0);
474	}
475	if (ctx->encrypt) {
476	cnow = dest;
477	plain = (u_char *)src;
478	cprev = c->r_iv;
479	for (i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE,
480	cnow+=RIJNDAEL_BLOCKSIZE) {
481	for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
482	buf[j] = plain[j] ^ cprev[j];
483	rijndael_encrypt(&c->r_ctx, buf, cnow);
484	cprev = cnow;
485	}
486	memcpy(c->r_iv, cprev, RIJNDAEL_BLOCKSIZE);
487	} else {
488	cnow = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE);
489	plain = dest+len-RIJNDAEL_BLOCKSIZE;
490
491	memcpy(buf, cnow, RIJNDAEL_BLOCKSIZE);
492	for (i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE,
493	plain-=RIJNDAEL_BLOCKSIZE) {
494	rijndael_decrypt(&c->r_ctx, cnow, plain);
495	ivp = (i == 1) ? c->r_iv : cnow-RIJNDAEL_BLOCKSIZE;
496	for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
497	plain[j] ^= ivp[j];
498	}
499	memcpy(c->r_iv, buf, RIJNDAEL_BLOCKSIZE);
500	}
501	return (1);
502	}
503	static int
504	ssh_rijndael_cleanup(EVP_CIPHER_CTX *ctx)
505	{
506	struct ssh_rijndael_ctx *c;
507
508	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
509	memset(c, 0, sizeof(*c));
510	xfree(c);
511	EVP_CIPHER_CTX_set_app_data(ctx, NULL);
512	}
513	return (1);
514	}
515	static EVP_CIPHER *
516	evp_rijndael(void)
517	{
518	static EVP_CIPHER rijndal_cbc;
519
520	memset(&rijndal_cbc, 0, sizeof(EVP_CIPHER));
521	rijndal_cbc.nid = NID_undef;
522	rijndal_cbc.block_size = RIJNDAEL_BLOCKSIZE;
523	rijndal_cbc.iv_len = RIJNDAEL_BLOCKSIZE;
524	rijndal_cbc.key_len = 16;
525	rijndal_cbc.init = ssh_rijndael_init;
526	rijndal_cbc.cleanup = ssh_rijndael_cleanup;
527	rijndal_cbc.do_cipher = ssh_rijndael_cbc;
492a3893	528	#if OPENSSL_VERSION_NUMBER > 0x0090600fL
70fc1609	529	rijndal_cbc.flags = EVP_CIPH_CBC_MODE \| EVP_CIPH_VARIABLE_LENGTH \|
70fc1609	530	EVP_CIPH_ALWAYS_CALL_INIT;
492a3893	531	#endif
70fc1609	532	return (&rijndal_cbc);
70fc1609	533	}