[gssapi-openssh.git] / openssh / 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 1.77 2005/07/16 01:35:24 djm Exp $");

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

#include <openssl/md5.h>

/* compatibility with old or broken OpenSSL versions */
#include "openbsd-compat/openssl-compat.h"

extern const EVP_CIPHER *evp_ssh1_bf(void);
extern const EVP_CIPHER *evp_ssh1_3des(void);
extern void ssh1_3des_iv(EVP_CIPHER_CTX *, int, u_char *, int);
extern const EVP_CIPHER *evp_aes_128_ctr(void);
extern void ssh_aes_ctr_iv(EVP_CIPHER_CTX *, int, u_char *, u_int);

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

	{ "3des-cbc",		SSH_CIPHER_SSH2, 8, 24, 0, EVP_des_ede3_cbc },
	{ "blowfish-cbc",	SSH_CIPHER_SSH2, 8, 16, 0, EVP_bf_cbc },
	{ "cast128-cbc",	SSH_CIPHER_SSH2, 8, 16, 0, EVP_cast5_cbc },
	{ "arcfour",		SSH_CIPHER_SSH2, 8, 16, 0, EVP_rc4 },
	{ "arcfour128",		SSH_CIPHER_SSH2, 8, 16, 1536, EVP_rc4 },
	{ "arcfour256",		SSH_CIPHER_SSH2, 8, 32, 1536, EVP_rc4 },
	{ "aes128-cbc",		SSH_CIPHER_SSH2, 16, 16, 0, EVP_aes_128_cbc },
	{ "aes192-cbc",		SSH_CIPHER_SSH2, 16, 24, 0, EVP_aes_192_cbc },
	{ "aes256-cbc",		SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc },
	{ "rijndael-cbc@lysator.liu.se",
				SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc },
	{ "aes128-ctr",		SSH_CIPHER_SSH2, 16, 16, 0, evp_aes_128_ctr },
	{ "aes192-ctr",		SSH_CIPHER_SSH2, 16, 24, 0, evp_aes_128_ctr },
	{ "aes256-ctr",		SSH_CIPHER_SSH2, 16, 32, 0, evp_aes_128_ctr },
#ifdef USE_CIPHER_ACSS
	{ "acss@openssh.org",	SSH_CIPHER_SSH2, 16, 5, 0, EVP_acss },
#endif
	{ NULL,			SSH_CIPHER_INVALID, 0, 0, 0, NULL }
};

/*--*/

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

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

u_int
cipher_get_number(const 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 (strcmp(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 *cipher_list, *cp;
	char *p;

	if (names == NULL || strcmp(names, "") == 0)
		return 0;
	cipher_list = 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 &&
				  c->number != SSH_CIPHER_NONE)) {
			debug("bad cipher %s [%s]", p, names);
			xfree(cipher_list);
			return 0;
		} else {
			debug3("cipher ok: %s [%s]", p, names);
		}
	}
	debug3("ciphers ok: [%s]", names);
	xfree(cipher_list);
	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;
	for (c = ciphers; c->name != NULL; c++)
		if (strcasecmp(c->name, name) == 0)
			return c->number;
	return -1;
}

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 do_encrypt)
{
	static int dowarn = 1;
#ifdef SSH_OLD_EVP
	EVP_CIPHER *type;
#else
	const EVP_CIPHER *type;
	int klen;
#endif
	u_char *junk, *discard;

	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,
	    (do_encrypt == CIPHER_ENCRYPT));
#else
	if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
	    (do_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 != (u_int)klen) {
		debug2("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

	if (cipher->discard_len > 0) {
		junk = xmalloc(cipher->discard_len);
		discard = xmalloc(cipher->discard_len);
		if (EVP_Cipher(&cc->evp, discard, junk,
		    cipher->discard_len) == 0)
			fatal("evp_crypt: EVP_Cipher failed during discard");
		memset(discard, 0, cipher->discard_len);
		xfree(junk);
		xfree(discard);
	}
}

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 (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
		fatal("evp_crypt: EVP_Cipher failed");
}

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

/*
 * 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 do_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, do_encrypt);

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

/*
 * 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(const 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;
	int evplen;

	switch (c->number) {
	case SSH_CIPHER_NONE:
	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 ((u_int)evplen != len)
			fatal("%s: wrong iv length %d != %d", __func__,
			    evplen, len);
#ifdef USE_BUILTIN_RIJNDAEL
		if (c->evptype == evp_rijndael)
			ssh_rijndael_iv(&cc->evp, 0, iv, len);
		else
#endif
		if (c->evptype == evp_aes_128_ctr)
			ssh_aes_ctr_iv(&cc->evp, 0, iv, len);
		else
			memcpy(iv, cc->evp.iv, len);
		break;
	case SSH_CIPHER_3DES:
		ssh1_3des_iv(&cc->evp, 0, iv, 24);
		break;
	default:
		fatal("%s: bad cipher %d", __func__, c->number);
	}
}

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

	switch (c->number) {
	case SSH_CIPHER_NONE:
	case SSH_CIPHER_SSH2:
	case SSH_CIPHER_DES:
	case SSH_CIPHER_BLOWFISH:
		evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
		if (evplen == 0)
			return;
#ifdef USE_BUILTIN_RIJNDAEL
		if (c->evptype == evp_rijndael)
			ssh_rijndael_iv(&cc->evp, 1, iv, evplen);
		else
#endif
		if (c->evptype == evp_aes_128_ctr)
			ssh_aes_ctr_iv(&cc->evp, 1, iv, evplen);
		else
			memcpy(cc->evp.iv, iv, evplen);
		break;
	case SSH_CIPHER_3DES:
		ssh1_3des_iv(&cc->evp, 1, iv, 24);
		break;
	default:
		fatal("%s: bad cipher %d", __func__, c->number);
	}
}

#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(const CipherContext *cc, u_char *dat)
{
	Cipher *c = cc->cipher;
	int plen = 0;

	if (c->evptype == EVP_rc4 || c->evptype == EVP_acss) {
		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->evptype == EVP_rc4 || c->evptype == EVP_acss) {
		plen = EVP_X_STATE_LEN(cc->evp);
		memcpy(EVP_X_STATE(cc->evp), dat, plen);
	}
}
Commit	Line	Data
3c0ef626	1	/*
	2	* Author: Tatu Ylonen <ylo@cs.hut.fi>
	3	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
	4	* All rights reserved
	5	*
	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.
	14	* Copyright (c) 1999, 2000 Markus Friedl. All rights reserved.
	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.
	24	*
	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.
	35	*/
	36
	37	#include "includes.h"
2ce0bfe4	38	RCSID("$OpenBSD: cipher.c,v 1.77 2005/07/16 01:35:24 djm Exp $");
3c0ef626	39
	40	#include "xmalloc.h"
	41	#include "log.h"
	42	#include "cipher.h"
	43
	44	#include <openssl/md5.h>
905081a4	45
2ce0bfe4	46	/* compatibility with old or broken OpenSSL versions */
2ce0bfe4	47	#include "openbsd-compat/openssl-compat.h"
540d72c3	48
7cac2b65	49	extern const EVP_CIPHER *evp_ssh1_bf(void);
	50	extern const EVP_CIPHER *evp_ssh1_3des(void);
	51	extern void ssh1_3des_iv(EVP_CIPHER_CTX , int, u_char , int);
	52	extern const EVP_CIPHER *evp_aes_128_ctr(void);
	53	extern void ssh_aes_ctr_iv(EVP_CIPHER_CTX , int, u_char , u_int);
905081a4	54
	55	struct Cipher {
	56	char *name;
	57	int number; /* for ssh1 only */
	58	u_int block_size;
	59	u_int key_len;
2ce0bfe4	60	u_int discard_len;
44a053a3	61	const EVP_CIPHER (evptype)(void);
905081a4	62	} ciphers[] = {
2ce0bfe4	63	{ "none", SSH_CIPHER_NONE, 8, 0, 0, EVP_enc_null },
	64	{ "des", SSH_CIPHER_DES, 8, 8, 0, EVP_des_cbc },
	65	{ "3des", SSH_CIPHER_3DES, 8, 16, 0, evp_ssh1_3des },
	66	{ "blowfish", SSH_CIPHER_BLOWFISH, 8, 32, 0, evp_ssh1_bf },
	67
	68	{ "3des-cbc", SSH_CIPHER_SSH2, 8, 24, 0, EVP_des_ede3_cbc },
	69	{ "blowfish-cbc", SSH_CIPHER_SSH2, 8, 16, 0, EVP_bf_cbc },
	70	{ "cast128-cbc", SSH_CIPHER_SSH2, 8, 16, 0, EVP_cast5_cbc },
	71	{ "arcfour", SSH_CIPHER_SSH2, 8, 16, 0, EVP_rc4 },
	72	{ "arcfour128", SSH_CIPHER_SSH2, 8, 16, 1536, EVP_rc4 },
	73	{ "arcfour256", SSH_CIPHER_SSH2, 8, 32, 1536, EVP_rc4 },
	74	{ "aes128-cbc", SSH_CIPHER_SSH2, 16, 16, 0, EVP_aes_128_cbc },
	75	{ "aes192-cbc", SSH_CIPHER_SSH2, 16, 24, 0, EVP_aes_192_cbc },
	76	{ "aes256-cbc", SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc },
350391c5	77	{ "rijndael-cbc@lysator.liu.se",
2ce0bfe4	78	SSH_CIPHER_SSH2, 16, 32, 0, EVP_aes_256_cbc },
	79	{ "aes128-ctr", SSH_CIPHER_SSH2, 16, 16, 0, evp_aes_128_ctr },
	80	{ "aes192-ctr", SSH_CIPHER_SSH2, 16, 24, 0, evp_aes_128_ctr },
	81	{ "aes256-ctr", SSH_CIPHER_SSH2, 16, 32, 0, evp_aes_128_ctr },
	82	#ifdef USE_CIPHER_ACSS
	83	{ "acss@openssh.org", SSH_CIPHER_SSH2, 16, 5, 0, EVP_acss },
29d88157	84	#endif
2ce0bfe4	85	{ NULL, SSH_CIPHER_INVALID, 0, 0, 0, NULL }
905081a4	86	};
3c0ef626	87
905081a4	88	/--/
3c0ef626	89
905081a4	90	u_int
540d72c3	91	cipher_blocksize(const Cipher *c)
3c0ef626	92	{
905081a4	93	return (c->block_size);
3c0ef626	94	}
276b07a3	95
905081a4	96	u_int
540d72c3	97	cipher_keylen(const Cipher *c)
3c0ef626	98	{
905081a4	99	return (c->key_len);
3c0ef626	100	}
276b07a3	101
905081a4	102	u_int
540d72c3	103	cipher_get_number(const Cipher *c)
3c0ef626	104	{
905081a4	105	return (c->number);
3c0ef626	106	}
3c0ef626	107
3c0ef626	108	u_int
	109	cipher_mask_ssh1(int client)
	110	{
	111	u_int mask = 0;
905081a4	112	mask \|= 1 << SSH_CIPHER_3DES; /* Mandatory */
3c0ef626	113	mask \|= 1 << SSH_CIPHER_BLOWFISH;
	114	if (client) {
	115	mask \|= 1 << SSH_CIPHER_DES;
	116	}
	117	return mask;
	118	}
	119
	120	Cipher *
	121	cipher_by_name(const char *name)
	122	{
	123	Cipher *c;
	124	for (c = ciphers; c->name != NULL; c++)
dfddba3d	125	if (strcmp(c->name, name) == 0)
3c0ef626	126	return c;
	127	return NULL;
	128	}
	129
	130	Cipher *
	131	cipher_by_number(int id)
	132	{
	133	Cipher *c;
	134	for (c = ciphers; c->name != NULL; c++)
	135	if (c->number == id)
	136	return c;
	137	return NULL;
	138	}
	139
	140	#define CIPHER_SEP ","
	141	int
	142	ciphers_valid(const char *names)
	143	{
	144	Cipher *c;
7e82606e	145	char cipher_list, cp;
3c0ef626	146	char *p;
	147
	148	if (names == NULL \|\| strcmp(names, "") == 0)
	149	return 0;
7e82606e	150	cipher_list = cp = xstrdup(names);
3c0ef626	151	for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
905081a4	152	(p = strsep(&cp, CIPHER_SEP))) {
3c0ef626	153	c = cipher_by_name(p);
8af0406b	154	if (c == NULL \|\| (c->number != SSH_CIPHER_SSH2 &&
8af0406b	155	c->number != SSH_CIPHER_NONE)) {
3c0ef626	156	debug("bad cipher %s [%s]", p, names);
7e82606e	157	xfree(cipher_list);
3c0ef626	158	return 0;
	159	} else {
	160	debug3("cipher ok: %s [%s]", p, names);
	161	}
	162	}
	163	debug3("ciphers ok: [%s]", names);
7e82606e	164	xfree(cipher_list);
3c0ef626	165	return 1;
	166	}
	167
	168	/*
	169	* Parses the name of the cipher. Returns the number of the corresponding
	170	* cipher, or -1 on error.
	171	*/
	172
	173	int
	174	cipher_number(const char *name)
	175	{
	176	Cipher *c;
	177	if (name == NULL)
	178	return -1;
dfddba3d	179	for (c = ciphers; c->name != NULL; c++)
	180	if (strcasecmp(c->name, name) == 0)
	181	return c->number;
	182	return -1;
3c0ef626	183	}
	184
	185	char *
	186	cipher_name(int id)
	187	{
	188	Cipher *c = cipher_by_number(id);
	189	return (c==NULL) ? "<unknown>" : c->name;
	190	}
	191
	192	void
	193	cipher_init(CipherContext cc, Cipher cipher,
905081a4	194	const u_char key, u_int keylen, const u_char iv, u_int ivlen,
7e82606e	195	int do_encrypt)
3c0ef626	196	{
905081a4	197	static int dowarn = 1;
350391c5	198	#ifdef SSH_OLD_EVP
	199	EVP_CIPHER *type;
	200	#else
905081a4	201	const EVP_CIPHER *type;
905081a4	202	int klen;
2ce0bfe4	203	#endif
2ce0bfe4	204	u_char junk, discard;
905081a4	205
	206	if (cipher->number == SSH_CIPHER_DES) {
	207	if (dowarn) {
	208	error("Warning: use of DES is strongly discouraged "
	209	"due to cryptographic weaknesses");
	210	dowarn = 0;
	211	}
	212	if (keylen > 8)
	213	keylen = 8;
	214	}
	215	cc->plaintext = (cipher->number == SSH_CIPHER_NONE);
	216
3c0ef626	217	if (keylen < cipher->key_len)
	218	fatal("cipher_init: key length %d is insufficient for %s.",
	219	keylen, cipher->name);
	220	if (iv != NULL && ivlen < cipher->block_size)
	221	fatal("cipher_init: iv length %d is insufficient for %s.",
	222	ivlen, cipher->name);
	223	cc->cipher = cipher;
905081a4	224
	225	type = (*cipher->evptype)();
	226
	227	EVP_CIPHER_CTX_init(&cc->evp);
350391c5	228	#ifdef SSH_OLD_EVP
	229	if (type->key_len > 0 && type->key_len != keylen) {
	230	debug("cipher_init: set keylen (%d -> %d)",
	231	type->key_len, keylen);
	232	type->key_len = keylen;
	233	}
	234	EVP_CipherInit(&cc->evp, type, (u_char )key, (u_char )iv,
7e82606e	235	(do_encrypt == CIPHER_ENCRYPT));
350391c5	236	#else
905081a4	237	if (EVP_CipherInit(&cc->evp, type, NULL, (u_char *)iv,
7e82606e	238	(do_encrypt == CIPHER_ENCRYPT)) == 0)
905081a4	239	fatal("cipher_init: EVP_CipherInit failed for %s",
	240	cipher->name);
	241	klen = EVP_CIPHER_CTX_key_length(&cc->evp);
2ce0bfe4	242	if (klen > 0 && keylen != (u_int)klen) {
bfe49944	243	debug2("cipher_init: set keylen (%d -> %d)", klen, keylen);
905081a4	244	if (EVP_CIPHER_CTX_set_key_length(&cc->evp, keylen) == 0)
	245	fatal("cipher_init: set keylen failed (%d -> %d)",
	246	klen, keylen);
	247	}
	248	if (EVP_CipherInit(&cc->evp, NULL, (u_char *)key, NULL, -1) == 0)
	249	fatal("cipher_init: EVP_CipherInit: set key failed for %s",
	250	cipher->name);
350391c5	251	#endif
2ce0bfe4	252
	253	if (cipher->discard_len > 0) {
	254	junk = xmalloc(cipher->discard_len);
	255	discard = xmalloc(cipher->discard_len);
	256	if (EVP_Cipher(&cc->evp, discard, junk,
	257	cipher->discard_len) == 0)
	258	fatal("evp_crypt: EVP_Cipher failed during discard");
	259	memset(discard, 0, cipher->discard_len);
	260	xfree(junk);
	261	xfree(discard);
	262	}
3c0ef626	263	}
	264
	265	void
905081a4	266	cipher_crypt(CipherContext cc, u_char dest, const u_char *src, u_int len)
3c0ef626	267	{
	268	if (len % cc->cipher->block_size)
	269	fatal("cipher_encrypt: bad plaintext length %d", len);
905081a4	270	if (EVP_Cipher(&cc->evp, dest, (u_char *)src, len) == 0)
905081a4	271	fatal("evp_crypt: EVP_Cipher failed");
3c0ef626	272	}
	273
	274	void
905081a4	275	cipher_cleanup(CipherContext *cc)
3c0ef626	276	{
905081a4	277	if (EVP_CIPHER_CTX_cleanup(&cc->evp) == 0)
905081a4	278	error("cipher_cleanup: EVP_CIPHER_CTX_cleanup failed");
3c0ef626	279	}
	280
	281	/*
	282	* Selects the cipher, and keys if by computing the MD5 checksum of the
	283	* passphrase and using the resulting 16 bytes as the key.
	284	*/
	285
	286	void
	287	cipher_set_key_string(CipherContext cc, Cipher cipher,
7e82606e	288	const char *passphrase, int do_encrypt)
3c0ef626	289	{
	290	MD5_CTX md;
	291	u_char digest[16];
	292
	293	MD5_Init(&md);
	294	MD5_Update(&md, (const u_char *)passphrase, strlen(passphrase));
	295	MD5_Final(digest, &md);
	296
7e82606e	297	cipher_init(cc, cipher, digest, 16, NULL, 0, do_encrypt);
3c0ef626	298
	299	memset(digest, 0, sizeof(digest));
	300	memset(&md, 0, sizeof(md));
	301	}
905081a4	302
905081a4	303	/*
	304	* Exports an IV from the CipherContext required to export the key
	305	* state back from the unprivileged child to the privileged parent
	306	* process.
	307	*/
	308
	309	int
540d72c3	310	cipher_get_keyiv_len(const CipherContext *cc)
905081a4	311	{
	312	Cipher *c = cc->cipher;
	313	int ivlen;
	314
	315	if (c->number == SSH_CIPHER_3DES)
	316	ivlen = 24;
	317	else
	318	ivlen = EVP_CIPHER_CTX_iv_length(&cc->evp);
	319	return (ivlen);
	320	}
	321
	322	void
	323	cipher_get_keyiv(CipherContext cc, u_char iv, u_int len)
	324	{
	325	Cipher *c = cc->cipher;
905081a4	326	int evplen;
	327
	328	switch (c->number) {
473db5ab	329	case SSH_CIPHER_NONE:
905081a4	330	case SSH_CIPHER_SSH2:
	331	case SSH_CIPHER_DES:
	332	case SSH_CIPHER_BLOWFISH:
	333	evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
2ce0bfe4	334	if (evplen <= 0)
905081a4	335	return;
2ce0bfe4	336	if ((u_int)evplen != len)
44a053a3	337	fatal("%s: wrong iv length %d != %d", __func__,
905081a4	338	evplen, len);
08822d99	339	#ifdef USE_BUILTIN_RIJNDAEL
7cac2b65	340	if (c->evptype == evp_rijndael)
	341	ssh_rijndael_iv(&cc->evp, 0, iv, len);
	342	else
44a053a3	343	#endif
7cac2b65	344	if (c->evptype == evp_aes_128_ctr)
	345	ssh_aes_ctr_iv(&cc->evp, 0, iv, len);
	346	else
	347	memcpy(iv, cc->evp.iv, len);
	348	break;
	349	case SSH_CIPHER_3DES:
	350	ssh1_3des_iv(&cc->evp, 0, iv, 24);
905081a4	351	break;
905081a4	352	default:
44a053a3	353	fatal("%s: bad cipher %d", __func__, c->number);
905081a4	354	}
905081a4	355	}
	356
	357	void
	358	cipher_set_keyiv(CipherContext cc, u_char iv)
	359	{
	360	Cipher *c = cc->cipher;
905081a4	361	int evplen = 0;
	362
	363	switch (c->number) {
473db5ab	364	case SSH_CIPHER_NONE:
905081a4	365	case SSH_CIPHER_SSH2:
	366	case SSH_CIPHER_DES:
	367	case SSH_CIPHER_BLOWFISH:
	368	evplen = EVP_CIPHER_CTX_iv_length(&cc->evp);
	369	if (evplen == 0)
	370	return;
08822d99	371	#ifdef USE_BUILTIN_RIJNDAEL
7cac2b65	372	if (c->evptype == evp_rijndael)
	373	ssh_rijndael_iv(&cc->evp, 1, iv, evplen);
	374	else
44a053a3	375	#endif
7cac2b65	376	if (c->evptype == evp_aes_128_ctr)
	377	ssh_aes_ctr_iv(&cc->evp, 1, iv, evplen);
	378	else
	379	memcpy(cc->evp.iv, iv, evplen);
	380	break;
	381	case SSH_CIPHER_3DES:
	382	ssh1_3des_iv(&cc->evp, 1, iv, 24);
905081a4	383	break;
905081a4	384	default:
44a053a3	385	fatal("%s: bad cipher %d", __func__, c->number);
905081a4	386	}
905081a4	387	}
	388
	389	#if OPENSSL_VERSION_NUMBER < 0x00907000L
	390	#define EVP_X_STATE(evp) &(evp).c
	391	#define EVP_X_STATE_LEN(evp) sizeof((evp).c)
	392	#else
	393	#define EVP_X_STATE(evp) (evp).cipher_data
	394	#define EVP_X_STATE_LEN(evp) (evp).cipher->ctx_size
	395	#endif
	396
	397	int
540d72c3	398	cipher_get_keycontext(const CipherContext cc, u_char dat)
905081a4	399	{
905081a4	400	Cipher *c = cc->cipher;
44a053a3	401	int plen = 0;
905081a4	402
540d72c3	403	if (c->evptype == EVP_rc4 \|\| c->evptype == EVP_acss) {
44a053a3	404	plen = EVP_X_STATE_LEN(cc->evp);
905081a4	405	if (dat == NULL)
44a053a3	406	return (plen);
44a053a3	407	memcpy(dat, EVP_X_STATE(cc->evp), plen);
905081a4	408	}
905081a4	409	return (plen);
	410	}
	411
	412	void
	413	cipher_set_keycontext(CipherContext cc, u_char dat)
	414	{
	415	Cipher *c = cc->cipher;
	416	int plen;
	417
540d72c3	418	if (c->evptype == EVP_rc4 \|\| c->evptype == EVP_acss) {
905081a4	419	plen = EVP_X_STATE_LEN(cc->evp);
	420	memcpy(EVP_X_STATE(cc->evp), dat, plen);
	421	}
	422	}