[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 1.55 2002/04/03 09:26:11 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 },
	{ "rijndael-cbc@lysator.liu.se",
				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_get_number(Cipher *c)
{
	return (c->number);
}

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);
}

/*
 * Exports an IV from the CipherContext required to export the key
 * state back from the unprivileged child to the privileged parent
 * process.
 */

int
cipher_get_keyiv_len(CipherContext *cc)
{
	Cipher *c = cc->cipher;
	int ivlen;

	if (c->number == SSH_CIPHER_3DES)
		ivlen = 24;
	else
		ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
	return (ivlen);
}

void
cipher_get_keyiv(CipherContext *cc, u_char *iv, u_int len)
{
	Cipher *c = cc->cipher;
	u_char *civ = NULL;
	int evplen;

	switch (c->number) {
	case SSH_CIPHER_SSH2:
	case SSH_CIPHER_DES:
	case SSH_CIPHER_BLOWFISH:
		evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
		if (evplen == 0)
			return;
		if (evplen != len)
			fatal("%s: wrong iv length %d != %d", __FUNCTION__,
			    evplen, len);

		if (c->evptype == evp_rijndael) {
			struct ssh_rijndael_ctx *aesc;

			aesc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
			if (aesc == NULL)
				fatal("%s: no rijndael context", __FUNCTION__);
			civ = aesc->r_iv;
		} else {
			civ = cc->evp.iv;
		}
		break;
	case SSH_CIPHER_3DES: {
		struct ssh1_3des_ctx *desc;
		if (len != 24)
			fatal("%s: bad 3des iv length: %d", __FUNCTION__, len);
		desc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
		if (desc == NULL)
			fatal("%s: no 3des context", __FUNCTION__);
		debug3("%s: Copying 3DES IV", __FUNCTION__);
		memcpy(iv, desc->k1.iv, 8);
		memcpy(iv + 8, desc->k2.iv, 8);
		memcpy(iv + 16, desc->k3.iv, 8);
		return;
	}
	default:
		fatal("%s: bad cipher %d", __FUNCTION__, c->number);
	}
	memcpy(iv, civ, len);
}

void
cipher_set_keyiv(CipherContext *cc, u_char *iv)
{
	Cipher *c = cc->cipher;
	u_char *div = NULL;
	int evplen = 0;

	switch (c->number) {
	case SSH_CIPHER_SSH2:
	case SSH_CIPHER_DES:
	case SSH_CIPHER_BLOWFISH:
		evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
		if (evplen == 0)
			return;

		if (c->evptype == evp_rijndael) {
			struct ssh_rijndael_ctx *aesc;

			aesc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
			if (aesc == NULL)
				fatal("%s: no rijndael context", __FUNCTION__);
			div = aesc->r_iv;
		}else {
			div = cc->evp.iv;
		}
		break;
	case SSH_CIPHER_3DES: {
		struct ssh1_3des_ctx *desc;
		desc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
		if (desc == NULL)
			fatal("%s: no 3des context", __FUNCTION__);
		debug3("%s: Installed 3DES IV", __FUNCTION__);
		memcpy(desc->k1.iv, iv, 8);
		memcpy(desc->k2.iv, iv + 8, 8);
		memcpy(desc->k3.iv, iv + 16, 8);
		return;
	}
	default:
		fatal("%s: bad cipher %d", __FUNCTION__, c->number);
	}
	memcpy(div, iv, evplen);
}

#if OPENSSL_VERSION_NUMBER < 0x00907000L
#define EVP_X_STATE(evp)	&(evp).c
#define EVP_X_STATE_LEN(evp)	sizeof((evp).c)
#else
#define EVP_X_STATE(evp)	(evp).cipher_data
#define EVP_X_STATE_LEN(evp)	(evp).cipher->ctx_size
#endif

int
cipher_get_keycontext(CipherContext *cc, u_char *dat)
{
	Cipher *c = cc->cipher;
	int plen;

	if (c->number == SSH_CIPHER_3DES) {
		struct ssh1_3des_ctx *desc;
		desc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
		if (desc == NULL)
			fatal("%s: no 3des context", __FUNCTION__);
		plen = EVP_X_STATE_LEN(desc->k1);
		if (dat == NULL)
			return (3*plen);
		memcpy(dat, EVP_X_STATE(desc->k1), plen);
		memcpy(dat + plen, EVP_X_STATE(desc->k2), plen);
		memcpy(dat + 2*plen, EVP_X_STATE(desc->k3), plen);
		return (3*plen);
	}

	/* Generic EVP */
	plen = EVP_X_STATE_LEN(cc->evp);
	if (dat == NULL)
		return (plen);

	memcpy(dat, EVP_X_STATE(cc->evp), plen);
	return (plen);
}

void
cipher_set_keycontext(CipherContext *cc, u_char *dat)
{
	Cipher *c = cc->cipher;
	int plen;

	if (c->number == SSH_CIPHER_3DES) {
		struct ssh1_3des_ctx *desc;
		desc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
		if (desc == NULL)
			fatal("%s: no 3des context", __FUNCTION__);
		plen = EVP_X_STATE_LEN(desc->k1);
		memcpy(EVP_X_STATE(desc->k1), dat, plen);
		memcpy(EVP_X_STATE(desc->k2), dat + plen, plen);
		memcpy(EVP_X_STATE(desc->k3), dat + 2*plen, plen);
	} else {
		plen = EVP_X_STATE_LEN(cc->evp);
		memcpy(EVP_X_STATE(cc->evp), dat, plen);
	}
}
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"
bf03f2da	38	RCSID("$OpenBSD: cipher.c,v 1.55 2002/04/03 09:26:11 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 },
bf03f2da	75	{ "rijndael-cbc@lysator.liu.se",
bf03f2da	76	SSH_CIPHER_SSH2, 16, 32, evp_rijndael },
70fc1609	77
70fc1609	78	{ NULL, SSH_CIPHER_ILLEGAL, 0, 0, NULL }
94ec8c6b	79	};
	80
	81	/--/
	82
762715ce	83	u_int
3ee832e5	84	cipher_blocksize(Cipher *c)
	85	{
	86	return (c->block_size);
	87	}
762715ce	88	u_int
3ee832e5	89	cipher_keylen(Cipher *c)
	90	{
	91	return (c->key_len);
	92	}
762715ce	93	u_int
bf8269a9	94	cipher_get_number(Cipher *c)
	95	{
	96	return (c->number);
	97	}
3ee832e5	98
1e3b8b07	99	u_int
94ec8c6b	100	cipher_mask_ssh1(int client)
8ce64345	101	{
1e3b8b07	102	u_int mask = 0;
184eed6a	103	mask \|= 1 << SSH_CIPHER_3DES; /* Mandatory */
94ec8c6b	104	mask \|= 1 << SSH_CIPHER_BLOWFISH;
	105	if (client) {
	106	mask \|= 1 << SSH_CIPHER_DES;
	107	}
5260325f	108	return mask;
8efc0c15	109	}
94ec8c6b	110
	111	Cipher *
	112	cipher_by_name(const char *name)
8ce64345	113	{
94ec8c6b	114	Cipher *c;
	115	for (c = ciphers; c->name != NULL; c++)
	116	if (strcasecmp(c->name, name) == 0)
	117	return c;
	118	return NULL;
8ce64345	119	}
8efc0c15	120
94ec8c6b	121	Cipher *
94ec8c6b	122	cipher_by_number(int id)
8efc0c15	123	{
94ec8c6b	124	Cipher *c;
	125	for (c = ciphers; c->name != NULL; c++)
	126	if (c->number == id)
	127	return c;
	128	return NULL;
8efc0c15	129	}
8efc0c15	130
a8be9f80	131	#define CIPHER_SEP ","
	132	int
	133	ciphers_valid(const char *names)
	134	{
94ec8c6b	135	Cipher *c;
089fbbd2	136	char ciphers, cp;
a8be9f80	137	char *p;
a8be9f80	138
71276795	139	if (names == NULL \|\| strcmp(names, "") == 0)
a8be9f80	140	return 0;
089fbbd2	141	ciphers = cp = xstrdup(names);
94ec8c6b	142	for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
184eed6a	143	(p = strsep(&cp, CIPHER_SEP))) {
94ec8c6b	144	c = cipher_by_name(p);
	145	if (c == NULL \|\| c->number != SSH_CIPHER_SSH2) {
	146	debug("bad cipher %s [%s]", p, names);
a8be9f80	147	xfree(ciphers);
a8be9f80	148	return 0;
94ec8c6b	149	} else {
33de75a3	150	debug3("cipher ok: %s [%s]", p, names);
a8be9f80	151	}
a8be9f80	152	}
33de75a3	153	debug3("ciphers ok: [%s]", names);
a8be9f80	154	xfree(ciphers);
	155	return 1;
	156	}
	157
aa3378df	158	/*
	159	* Parses the name of the cipher. Returns the number of the corresponding
	160	* cipher, or -1 on error.
	161	*/
8efc0c15	162
	163	int
	164	cipher_number(const char *name)
	165	{
94ec8c6b	166	Cipher *c;
71276795	167	if (name == NULL)
71276795	168	return -1;
94ec8c6b	169	c = cipher_by_name(name);
	170	return (c==NULL) ? -1 : c->number;
	171	}
	172
	173	char *
	174	cipher_name(int id)
	175	{
	176	Cipher *c = cipher_by_number(id);
	177	return (c==NULL) ? "<unknown>" : c->name;
	178	}
	179
	180	void
70fc1609	181	cipher_init(CipherContext cc, Cipher cipher,
	182	const u_char key, u_int keylen, const u_char iv, u_int ivlen,
	183	int encrypt)
94ec8c6b	184	{
70fc1609	185	static int dowarn = 1;
a068d86f	186	#ifdef SSH_OLD_EVP
	187	EVP_CIPHER *type;
	188	#else
70fc1609	189	const EVP_CIPHER *type;
a068d86f	190	#endif
70fc1609	191	int klen;
	192
	193	if (cipher->number == SSH_CIPHER_DES) {
	194	if (dowarn) {
	195	error("Warning: use of DES is strongly discouraged "
	196	"due to cryptographic weaknesses");
	197	dowarn = 0;
	198	}
	199	if (keylen > 8)
	200	keylen = 8;
	201	}
	202	cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
	203
94ec8c6b	204	if (keylen < cipher->key_len)
	205	fatal("cipher_init: key length %d is insufficient for %s.",
	206	keylen, cipher->name);
	207	if (iv != NULL && ivlen < cipher->block_size)
	208	fatal("cipher_init: iv length %d is insufficient for %s.",
	209	ivlen, cipher->name);
	210	cc->cipher = cipher;
70fc1609	211
	212	type = (*cipher->evptype)();
	213
	214	EVP_CIPHER_CTX_init(&cc->evp);
a068d86f	215	#ifdef SSH_OLD_EVP
	216	if (type->key_len > 0 && type->key_len != keylen) {
	217	debug("cipher_init: set keylen (%d -> %d)",
	218	type->key_len, keylen);
	219	type->key_len = keylen;
	220	}
	221	EVP_CipherInit(&cc->evp, type, (u_char )key, (u_char )iv,
	222	(encrypt == CIPHER_ENCRYPT));
	223	#else
70fc1609	224	if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
	225	(encrypt == CIPHER_ENCRYPT)) == 0)
	226	fatal("cipher_init: EVP_CipherInit failed for %s",
	227	cipher->name);
	228	klen = EVP_CIPHER_CTX_key_length(&cc->evp);
	229	if (klen > 0 && keylen != klen) {
	230	debug("cipher_init: set keylen (%d -> %d)", klen, keylen);
	231	if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
	232	fatal("cipher_init: set keylen failed (%d -> %d)",
	233	klen, keylen);
	234	}
	235	if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
	236	fatal("cipher_init: EVP_CipherInit: set key failed for %s",
	237	cipher->name);
a068d86f	238	#endif
94ec8c6b	239	}
	240
	241	void
3ee832e5	242	cipher_crypt(CipherContext cc, u_char dest, const u_char *src, u_int len)
94ec8c6b	243	{
	244	if (len % cc->cipher->block_size)
	245	fatal("cipher_encrypt: bad plaintext length %d", len);
a068d86f	246	#ifdef SSH_OLD_EVP
	247	EVP_Cipher(&cc->evp, dest, (u_char *)src, len);
	248	#else
70fc1609	249	if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
70fc1609	250	fatal("evp_crypt: EVP_Cipher failed");
a068d86f	251	#endif
94ec8c6b	252	}
	253
	254	void
3ee832e5	255	cipher_cleanup(CipherContext *cc)
94ec8c6b	256	{
a068d86f	257	#ifdef SSH_OLD_EVP
	258	EVP_CIPHER_CTX_cleanup(&cc->evp);
	259	#else
70fc1609	260	if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
70fc1609	261	error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
a068d86f	262	#endif
8efc0c15	263	}
8efc0c15	264
aa3378df	265	/*
	266	* Selects the cipher, and keys if by computing the MD5 checksum of the
	267	* passphrase and using the resulting 16 bytes as the key.
	268	*/
8efc0c15	269
6ae2364d	270	void
94ec8c6b	271	cipher_set_key_string(CipherContext cc, Cipher cipher,
3ee832e5	272	const char *passphrase, int encrypt)
8efc0c15	273	{
5260325f	274	MD5_CTX md;
1e3b8b07	275	u_char digest[16];
5260325f	276
5260325f	277	MD5_Init(&md);
94ec8c6b	278	MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
5260325f	279	MD5_Final(digest, &md);
5260325f	280
3ee832e5	281	cipher_init(cc, cipher, digest, 16, NULL, 0, encrypt);
5260325f	282
	283	memset(digest, 0, sizeof(digest));
	284	memset(&md, 0, sizeof(md));
8efc0c15	285	}
70fc1609	286
	287	/* Implementations for other non-EVP ciphers */
	288
	289	/*
	290	* This is used by SSH1:
	291	*
	292	* What kind of triple DES are these 2 routines?
	293	*
	294	* Why is there a redundant initialization vector?
	295	*
	296	* If only iv3 was used, then, this would till effect have been
	297	* outer-cbc. However, there is also a private iv1 == iv2 which
	298	* perhaps makes differential analysis easier. On the other hand, the
	299	* private iv1 probably makes the CRC-32 attack ineffective. This is a
	300	* result of that there is no longer any known iv1 to use when
	301	* choosing the X block.
	302	*/
	303	struct ssh1_3des_ctx
	304	{
	305	EVP_CIPHER_CTX k1, k2, k3;
	306	};
	307	static int
	308	ssh1_3des_init(EVP_CIPHER_CTX ctx, const u_char key, const u_char *iv,
	309	int enc)
	310	{
	311	struct ssh1_3des_ctx *c;
	312	u_char k1, k2, *k3;
	313
	314	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
	315	c = xmalloc(sizeof(*c));
	316	EVP_CIPHER_CTX_set_app_data(ctx, c);
	317	}
	318	if (key == NULL)
	319	return (1);
	320	if (enc == -1)
	321	enc = ctx->encrypt;
	322	k1 = k2 = k3 = (u_char *) key;
	323	k2 += 8;
	324	if (EVP_CIPHER_CTX_key_length(ctx) >= 16+8) {
	325	if (enc)
	326	k3 += 16;
	327	else
	328	k1 += 16;
	329	}
	330	EVP_CIPHER_CTX_init(&c->k1);
	331	EVP_CIPHER_CTX_init(&c->k2);
	332	EVP_CIPHER_CTX_init(&c->k3);
a068d86f	333	#ifdef SSH_OLD_EVP
	334	EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc);
	335	EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc);
	336	EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc);
	337	#else
70fc1609	338	if (EVP_CipherInit(&c->k1, EVP_des_cbc(), k1, NULL, enc) == 0 \|\|
	339	EVP_CipherInit(&c->k2, EVP_des_cbc(), k2, NULL, !enc) == 0 \|\|
	340	EVP_CipherInit(&c->k3, EVP_des_cbc(), k3, NULL, enc) == 0) {
	341	memset(c, 0, sizeof(*c));
	342	xfree(c);
	343	EVP_CIPHER_CTX_set_app_data(ctx, NULL);
	344	return (0);
	345	}
a068d86f	346	#endif
70fc1609	347	return (1);
	348	}
	349	static int
	350	ssh1_3des_cbc(EVP_CIPHER_CTX ctx, u_char dest, const u_char *src, u_int len)
	351	{
	352	struct ssh1_3des_ctx *c;
	353
	354	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
	355	error("ssh1_3des_cbc: no context");
	356	return (0);
	357	}
a068d86f	358	#ifdef SSH_OLD_EVP
	359	EVP_Cipher(&c->k1, dest, (u_char *)src, len);
	360	EVP_Cipher(&c->k2, dest, dest, len);
	361	EVP_Cipher(&c->k3, dest, dest, len);
	362	#else
70fc1609	363	if (EVP_Cipher(&c->k1, dest, (u_char *)src, len) == 0 \|\|
	364	EVP_Cipher(&c->k2, dest, dest, len) == 0 \|\|
	365	EVP_Cipher(&c->k3, dest, dest, len) == 0)
	366	return (0);
a068d86f	367	#endif
70fc1609	368	return (1);
	369	}
	370	static int
	371	ssh1_3des_cleanup(EVP_CIPHER_CTX *ctx)
	372	{
	373	struct ssh1_3des_ctx *c;
	374
	375	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
	376	memset(c, 0, sizeof(*c));
	377	xfree(c);
	378	EVP_CIPHER_CTX_set_app_data(ctx, NULL);
	379	}
	380	return (1);
	381	}
	382	static EVP_CIPHER *
	383	evp_ssh1_3des(void)
	384	{
	385	static EVP_CIPHER ssh1_3des;
	386
	387	memset(&ssh1_3des, 0, sizeof(EVP_CIPHER));
	388	ssh1_3des.nid = NID_undef;
	389	ssh1_3des.block_size = 8;
	390	ssh1_3des.iv_len = 0;
	391	ssh1_3des.key_len = 16;
	392	ssh1_3des.init = ssh1_3des_init;
	393	ssh1_3des.cleanup = ssh1_3des_cleanup;
	394	ssh1_3des.do_cipher = ssh1_3des_cbc;
a068d86f	395	#ifndef SSH_OLD_EVP
70fc1609	396	ssh1_3des.flags = EVP_CIPH_CBC_MODE \| EVP_CIPH_VARIABLE_LENGTH;
a068d86f	397	#endif
70fc1609	398	return (&ssh1_3des);
	399	}
	400
	401	/*
	402	* SSH1 uses a variation on Blowfish, all bytes must be swapped before
	403	* and after encryption/decryption. Thus the swap_bytes stuff (yuk).
	404	*/
	405	static void
	406	swap_bytes(const u_char src, u_char dst, int n)
	407	{
	408	u_char c[4];
	409
	410	/* Process 4 bytes every lap. */
	411	for (n = n / 4; n > 0; n--) {
	412	c[3] = *src++;
	413	c[2] = *src++;
	414	c[1] = *src++;
	415	c[0] = *src++;
	416
	417	*dst++ = c[0];
	418	*dst++ = c[1];
	419	*dst++ = c[2];
	420	*dst++ = c[3];
	421	}
	422	}
	423	static int (orig_bf)(EVP_CIPHER_CTX , u_char , const u_char , u_int) = NULL;
	424	static int
	425	bf_ssh1_cipher(EVP_CIPHER_CTX ctx, u_char out, const u_char *in, u_int len)
	426	{
	427	int ret;
	428
	429	swap_bytes(in, out, len);
	430	ret = (*orig_bf)(ctx, out, out, len);
	431	swap_bytes(out, out, len);
	432	return (ret);
	433	}
	434	static EVP_CIPHER *
	435	evp_ssh1_bf(void)
	436	{
	437	static EVP_CIPHER ssh1_bf;
	438
	439	memcpy(&ssh1_bf, EVP_bf_cbc(), sizeof(EVP_CIPHER));
	440	orig_bf = ssh1_bf.do_cipher;
	441	ssh1_bf.nid = NID_undef;
	442	ssh1_bf.do_cipher = bf_ssh1_cipher;
	443	ssh1_bf.key_len = 32;
	444	return (&ssh1_bf);
	445	}
	446
	447	/* RIJNDAEL */
	448	#define RIJNDAEL_BLOCKSIZE 16
	449	struct ssh_rijndael_ctx
	450	{
	451	rijndael_ctx r_ctx;
	452	u_char r_iv[RIJNDAEL_BLOCKSIZE];
	453	};
	454
	455	static int
	456	ssh_rijndael_init(EVP_CIPHER_CTX ctx, const u_char key, const u_char *iv,
	457	int enc)
	458	{
	459	struct ssh_rijndael_ctx *c;
	460
	461	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
462	c = xmalloc(sizeof(*c));
463	EVP_CIPHER_CTX_set_app_data(ctx, c);
464	}
465	if (key != NULL) {
466	if (enc == -1)
467	enc = ctx->encrypt;
468	rijndael_set_key(&c->r_ctx, (u_char *)key,
469	8*EVP_CIPHER_CTX_key_length(ctx), enc);
470	}
471	if (iv != NULL)
472	memcpy(c->r_iv, iv, RIJNDAEL_BLOCKSIZE);
473	return (1);
474	}
475	static int
476	ssh_rijndael_cbc(EVP_CIPHER_CTX ctx, u_char dest, const u_char *src,
477	u_int len)
478	{
479	struct ssh_rijndael_ctx *c;
480	u_char buf[RIJNDAEL_BLOCKSIZE];
481	u_char cprev, cnow, plain, ivp;
482	int i, j, blocks = len / RIJNDAEL_BLOCKSIZE;
483
484	if (len == 0)
485	return (1);
486	if (len % RIJNDAEL_BLOCKSIZE)
487	fatal("ssh_rijndael_cbc: bad len %d", len);
488	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
489	error("ssh_rijndael_cbc: no context");
490	return (0);
491	}
492	if (ctx->encrypt) {
493	cnow = dest;
494	plain = (u_char *)src;
495	cprev = c->r_iv;
496	for (i = 0; i < blocks; i++, plain+=RIJNDAEL_BLOCKSIZE,
497	cnow+=RIJNDAEL_BLOCKSIZE) {
498	for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
499	buf[j] = plain[j] ^ cprev[j];
500	rijndael_encrypt(&c->r_ctx, buf, cnow);
501	cprev = cnow;
502	}
503	memcpy(c->r_iv, cprev, RIJNDAEL_BLOCKSIZE);
504	} else {
505	cnow = (u_char *) (src+len-RIJNDAEL_BLOCKSIZE);
506	plain = dest+len-RIJNDAEL_BLOCKSIZE;
507
508	memcpy(buf, cnow, RIJNDAEL_BLOCKSIZE);
509	for (i = blocks; i > 0; i--, cnow-=RIJNDAEL_BLOCKSIZE,
510	plain-=RIJNDAEL_BLOCKSIZE) {
511	rijndael_decrypt(&c->r_ctx, cnow, plain);
05976246	512	ivp = (i == 1) ? c->r_iv : cnow-RIJNDAEL_BLOCKSIZE;
	513	for (j = 0; j < RIJNDAEL_BLOCKSIZE; j++)
	514	plain[j] ^= ivp[j];
	515	}
	516	memcpy(c->r_iv, buf, RIJNDAEL_BLOCKSIZE);
	517	}
	518	return (1);
	519	}
	520	static int
	521	ssh_rijndael_cleanup(EVP_CIPHER_CTX *ctx)
	522	{
	523	struct ssh_rijndael_ctx *c;
	524
	525	if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
	526	memset(c, 0, sizeof(*c));
	527	xfree(c);
	528	EVP_CIPHER_CTX_set_app_data(ctx, NULL);
	529	}
	530	return (1);
	531	}
	532	static EVP_CIPHER *
	533	evp_rijndael(void)
	534	{
	535	static EVP_CIPHER rijndal_cbc;
	536
	537	memset(&rijndal_cbc, 0, sizeof(EVP_CIPHER));
	538	rijndal_cbc.nid = NID_undef;
	539	rijndal_cbc.block_size = RIJNDAEL_BLOCKSIZE;
	540	rijndal_cbc.iv_len = RIJNDAEL_BLOCKSIZE;
	541	rijndal_cbc.key_len = 16;
	542	rijndal_cbc.init = ssh_rijndael_init;
	543	rijndal_cbc.cleanup = ssh_rijndael_cleanup;
	544	rijndal_cbc.do_cipher = ssh_rijndael_cbc;
	545	#ifndef SSH_OLD_EVP
	546	rijndal_cbc.flags = EVP_CIPH_CBC_MODE \| EVP_CIPH_VARIABLE_LENGTH \|
	547	EVP_CIPH_ALWAYS_CALL_INIT;
	548	#endif
	549	return (&rijndal_cbc);
bf8269a9	550	}
bf8269a9	551
762715ce	552	/*
bf8269a9	553	* Exports an IV from the CipherContext required to export the key
	554	* state back from the unprivileged child to the privileged parent
	555	* process.
	556	*/
	557
	558	int
	559	cipher_get_keyiv_len(CipherContext *cc)
	560	{
	561	Cipher *c = cc->cipher;
	562	int ivlen;
	563
	564	if (c->number == SSH_CIPHER_3DES)
	565	ivlen = 24;
	566	else
	567	ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
	568	return (ivlen);
	569	}
	570
	571	void
	572	cipher_get_keyiv(CipherContext cc, u_char iv, u_int len)
	573	{
	574	Cipher *c = cc->cipher;
	575	u_char *civ = NULL;
	576	int evplen;
	577
	578	switch (c->number) {
	579	case SSH_CIPHER_SSH2:
	580	case SSH_CIPHER_DES:
	581	case SSH_CIPHER_BLOWFISH:
	582	evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
	583	if (evplen == 0)
	584	return;
	585	if (evplen != len)
	586	fatal("%s: wrong iv length %d != %d", __FUNCTION__,
	587	evplen, len);
	588
bf03f2da	589	if (c->evptype == evp_rijndael) {
bf8269a9	590	struct ssh_rijndael_ctx *aesc;
	591
	592	aesc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
	593	if (aesc == NULL)
	594	fatal("%s: no rijndael context", __FUNCTION__);
	595	civ = aesc->r_iv;
	596	} else {
	597	civ = cc->evp.iv;
	598	}
	599	break;
	600	case SSH_CIPHER_3DES: {
	601	struct ssh1_3des_ctx *desc;
	602	if (len != 24)
	603	fatal("%s: bad 3des iv length: %d", __FUNCTION__, len);
	604	desc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
	605	if (desc == NULL)
	606	fatal("%s: no 3des context", __FUNCTION__);
	607	debug3("%s: Copying 3DES IV", __FUNCTION__);
	608	memcpy(iv, desc->k1.iv, 8);
	609	memcpy(iv + 8, desc->k2.iv, 8);
	610	memcpy(iv + 16, desc->k3.iv, 8);
	611	return;
	612	}
	613	default:
	614	fatal("%s: bad cipher %d", __FUNCTION__, c->number);
	615	}
	616	memcpy(iv, civ, len);
	617	}
	618
	619	void
	620	cipher_set_keyiv(CipherContext cc, u_char iv)
	621	{
	622	Cipher *c = cc->cipher;
	623	u_char *div = NULL;
	624	int evplen = 0;
	625
	626	switch (c->number) {
	627	case SSH_CIPHER_SSH2:
	628	case SSH_CIPHER_DES:
	629	case SSH_CIPHER_BLOWFISH:
	630	evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
	631	if (evplen == 0)
	632	return;
	633
bf03f2da	634	if (c->evptype == evp_rijndael) {
bf8269a9	635	struct ssh_rijndael_ctx *aesc;
	636
	637	aesc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
	638	if (aesc == NULL)
	639	fatal("%s: no rijndael context", __FUNCTION__);
	640	div = aesc->r_iv;
	641	}else {
	642	div = cc->evp.iv;
	643	}
	644	break;
	645	case SSH_CIPHER_3DES: {
	646	struct ssh1_3des_ctx *desc;
	647	desc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
	648	if (desc == NULL)
	649	fatal("%s: no 3des context", __FUNCTION__);
	650	debug3("%s: Installed 3DES IV", __FUNCTION__);
	651	memcpy(desc->k1.iv, iv, 8);
	652	memcpy(desc->k2.iv, iv + 8, 8);
	653	memcpy(desc->k3.iv, iv + 16, 8);
	654	return;
762715ce	655	}
bf8269a9	656	default:
	657	fatal("%s: bad cipher %d", __FUNCTION__, c->number);
	658	}
	659	memcpy(div, iv, evplen);
	660	}
	661
	662	#if OPENSSL_VERSION_NUMBER < 0x00907000L
	663	#define EVP_X_STATE(evp) &(evp).c
	664	#define EVP_X_STATE_LEN(evp) sizeof((evp).c)
	665	#else
	666	#define EVP_X_STATE(evp) (evp).cipher_data
	667	#define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size
	668	#endif
	669
	670	int
	671	cipher_get_keycontext(CipherContext cc, u_char dat)
	672	{
	673	Cipher *c = cc->cipher;
	674	int plen;
	675
	676	if (c->number == SSH_CIPHER_3DES) {
	677	struct ssh1_3des_ctx *desc;
	678	desc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
	679	if (desc == NULL)
	680	fatal("%s: no 3des context", __FUNCTION__);
	681	plen = EVP_X_STATE_LEN(desc->k1);
	682	if (dat == NULL)
	683	return (3*plen);
	684	memcpy(dat, EVP_X_STATE(desc->k1), plen);
	685	memcpy(dat + plen, EVP_X_STATE(desc->k2), plen);
	686	memcpy(dat + 2*plen, EVP_X_STATE(desc->k3), plen);
	687	return (3*plen);
	688	}
	689
	690	/* Generic EVP */
	691	plen = EVP_X_STATE_LEN(cc->evp);
	692	if (dat == NULL)
	693	return (plen);
	694
	695	memcpy(dat, EVP_X_STATE(cc->evp), plen);
	696	return (plen);
	697	}
	698
	699	void
	700	cipher_set_keycontext(CipherContext cc, u_char dat)
	701	{
	702	Cipher *c = cc->cipher;
	703	int plen;
	704
	705	if (c->number == SSH_CIPHER_3DES) {
	706	struct ssh1_3des_ctx *desc;
	707	desc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
	708	if (desc == NULL)
	709	fatal("%s: no 3des context", __FUNCTION__);
	710	plen = EVP_X_STATE_LEN(desc->k1);
	711	memcpy(EVP_X_STATE(desc->k1), dat, plen);
	712	memcpy(EVP_X_STATE(desc->k2), dat + plen, plen);
	713	memcpy(EVP_X_STATE(desc->k3), dat + 2*plen, plen);
	714	} else {
	715	plen = EVP_X_STATE_LEN(cc->evp);
	716	memcpy(EVP_X_STATE(cc->evp), dat, plen);
	717	}
70fc1609	718	}