[openssh.git] / cipher.c

/*
 *
 * cipher.c
 *
 * Author: Tatu Ylonen <ylo@cs.hut.fi>
 *
 * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
 *                    All rights reserved
 *
 * Created: Wed Apr 19 17:41:39 1995 ylo
 *
 */

#include "includes.h"
RCSID("$OpenBSD: cipher.c,v 1.29 2000/07/10 16:30:25 ho Exp $");

#include "ssh.h"
#include "cipher.h"
#include "xmalloc.h"

#include <openssl/md5.h>

/*
 * 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.
 */
void
SSH_3CBC_ENCRYPT(des_key_schedule ks1,
		 des_key_schedule ks2, des_cblock * iv2,
		 des_key_schedule ks3, des_cblock * iv3,
		 unsigned char *dest, unsigned char *src,
		 unsigned int len)
{
	des_cblock iv1;

	memcpy(&iv1, iv2, 8);

	des_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT);
	memcpy(&iv1, dest + len - 8, 8);

	des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT);
	memcpy(iv2, &iv1, 8);	/* Note how iv1 == iv2 on entry and exit. */

	des_cbc_encrypt(dest, dest, len, ks3, iv3, DES_ENCRYPT);
	memcpy(iv3, dest + len - 8, 8);
}

void
SSH_3CBC_DECRYPT(des_key_schedule ks1,
		 des_key_schedule ks2, des_cblock * iv2,
		 des_key_schedule ks3, des_cblock * iv3,
		 unsigned char *dest, unsigned char *src,
		 unsigned int len)
{
	des_cblock iv1;

	memcpy(&iv1, iv2, 8);

	des_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT);
	memcpy(iv3, src + len - 8, 8);

	des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT);
	memcpy(iv2, dest + len - 8, 8);

	des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT);
	/* memcpy(&iv1, iv2, 8); */
	/* Note how iv1 == iv2 on entry and exit. */
}

/*
 * 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 unsigned char *src, unsigned char *dst_, int n)
{
	/* dst must be properly aligned. */
	u_int32_t *dst = (u_int32_t *) dst_;
	union {
		u_int32_t i;
		char c[4];
	} t;

	/* Process 8 bytes every lap. */
	for (n = n / 8; n > 0; n--) {
		t.c[3] = *src++;
		t.c[2] = *src++;
		t.c[1] = *src++;
		t.c[0] = *src++;
		*dst++ = t.i;

		t.c[3] = *src++;
		t.c[2] = *src++;
		t.c[1] = *src++;
		t.c[0] = *src++;
		*dst++ = t.i;
	}
}

/*
 * Names of all encryption algorithms.
 * These must match the numbers defined in cipher.h.
 */
static char *cipher_names[] =
{
	"none",
	"idea",
	"des",
	"3des",
	"tss",
	"rc4",
	"blowfish",
	"reserved",
	"blowfish-cbc",
	"3des-cbc",
	"arcfour",
	"cast128-cbc"
};

/*
 * Returns a bit mask indicating which ciphers are supported by this
 * implementation.  The bit mask has the corresponding bit set of each
 * supported cipher.
 */

unsigned int
cipher_mask1()
{
	unsigned int mask = 0;
	mask |= 1 << SSH_CIPHER_3DES;		/* Mandatory */
	mask |= 1 << SSH_CIPHER_BLOWFISH;
	return mask;
}
unsigned int
cipher_mask2()
{
	unsigned int mask = 0;
	mask |= 1 << SSH_CIPHER_BLOWFISH_CBC;
	mask |= 1 << SSH_CIPHER_3DES_CBC;
	mask |= 1 << SSH_CIPHER_ARCFOUR;
	mask |= 1 << SSH_CIPHER_CAST128_CBC;
	return mask;
}
unsigned int
cipher_mask()
{
	return cipher_mask1() | cipher_mask2();
}

/* Returns the name of the cipher. */

const char *
cipher_name(int cipher)
{
	if (cipher < 0 || cipher >= sizeof(cipher_names) / sizeof(cipher_names[0]) ||
	    cipher_names[cipher] == NULL)
		fatal("cipher_name: bad cipher name: %d", cipher);
	return cipher_names[cipher];
}

/* Returns 1 if the name of the ciphers are valid. */

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

	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))) {
		i = cipher_number(p);
		if (i == -1 || !(cipher_mask2() & (1 << i))) {
			xfree(ciphers);
			return 0;
		}
	}
	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)
{
	int i;
	if (name == NULL)
		return -1;
	for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++)
		if (strcmp(cipher_names[i], name) == 0 &&
		    (cipher_mask() & (1 << i)))
			return i;
	return -1;
}

/*
 * 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 *context, int cipher, const char *passphrase)
{
	MD5_CTX md;
	unsigned char digest[16];

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

	cipher_set_key(context, cipher, digest, 16);

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

/* Selects the cipher to use and sets the key. */

void
cipher_set_key(CipherContext *context, int cipher, const unsigned char *key,
    int keylen)
{
	unsigned char padded[32];

	/* Set cipher type. */
	context->type = cipher;

	/* Get 32 bytes of key data.  Pad if necessary.  (So that code
	   below does not need to worry about key size). */
	memset(padded, 0, sizeof(padded));
	memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded));

	/* Initialize the initialization vector. */
	switch (cipher) {
	case SSH_CIPHER_NONE:
		/*
		 * Has to stay for authfile saving of private key with no
		 * passphrase
		 */
		break;

	case SSH_CIPHER_3DES:
		/*
		 * Note: the least significant bit of each byte of key is
		 * parity, and must be ignored by the implementation.  16
		 * bytes of key are used (first and last keys are the same).
		 */
		if (keylen < 16)
			error("Key length %d is insufficient for 3DES.", keylen);
		des_set_key((void *) padded, context->u.des3.key1);
		des_set_key((void *) (padded + 8), context->u.des3.key2);
		if (keylen <= 16)
			des_set_key((void *) padded, context->u.des3.key3);
		else
			des_set_key((void *) (padded + 16), context->u.des3.key3);
		memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2));
		memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3));
		break;

	case SSH_CIPHER_BLOWFISH:
		if (keylen < 16)
			error("Key length %d is insufficient for blowfish.", keylen);
		BF_set_key(&context->u.bf.key, keylen, padded);
		memset(context->u.bf.iv, 0, 8);
		break;

	case SSH_CIPHER_3DES_CBC:
	case SSH_CIPHER_BLOWFISH_CBC:
	case SSH_CIPHER_ARCFOUR:
	case SSH_CIPHER_CAST128_CBC:
		fatal("cipher_set_key: illegal cipher: %s", cipher_name(cipher));
		break;

	default:
		fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
	}
	memset(padded, 0, sizeof(padded));
}

void
cipher_set_key_iv(CipherContext * context, int cipher,
    const unsigned char *key, int keylen,
    const unsigned char *iv, int ivlen)
{
	/* Set cipher type. */
	context->type = cipher;

	/* Initialize the initialization vector. */
	switch (cipher) {
	case SSH_CIPHER_NONE:
		break;

	case SSH_CIPHER_3DES:
	case SSH_CIPHER_BLOWFISH:
		fatal("cipher_set_key_iv: illegal cipher: %s", cipher_name(cipher));
		break;

	case SSH_CIPHER_3DES_CBC:
		if (keylen < 24)
			error("Key length %d is insufficient for 3des-cbc.", keylen);
		des_set_key((void *) key, context->u.des3.key1);
		des_set_key((void *) (key+8), context->u.des3.key2);
		des_set_key((void *) (key+16), context->u.des3.key3);
		if (ivlen < 8)
			error("IV length %d is insufficient for 3des-cbc.", ivlen);
		memcpy(context->u.des3.iv3, (char *)iv, 8);
		break;

	case SSH_CIPHER_BLOWFISH_CBC:
		if (keylen < 16)
			error("Key length %d is insufficient for blowfish.", keylen);
		if (ivlen < 8)
			error("IV length %d is insufficient for blowfish.", ivlen);
		BF_set_key(&context->u.bf.key, keylen, (unsigned char *)key);
		memcpy(context->u.bf.iv, (char *)iv, 8);
		break;

	case SSH_CIPHER_ARCFOUR:
		if (keylen < 16)
			error("Key length %d is insufficient for arcfour.", keylen);
		RC4_set_key(&context->u.rc4, keylen, (unsigned char *)key);
		break;

	case SSH_CIPHER_CAST128_CBC:
		if (keylen < 16)
			error("Key length %d is insufficient for cast128.", keylen);
		if (ivlen < 8)
			error("IV length %d is insufficient for cast128.", ivlen);
		CAST_set_key(&context->u.cast.key, keylen, (unsigned char *) key);
		memcpy(context->u.cast.iv, (char *)iv, 8);
		break;

	default:
		fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
	}
}

/* Encrypts data using the cipher. */

void
cipher_encrypt(CipherContext *context, unsigned char *dest,
	       const unsigned char *src, unsigned int len)
{
	if ((len & 7) != 0)
		fatal("cipher_encrypt: bad plaintext length %d", len);

	switch (context->type) {
	case SSH_CIPHER_NONE:
		memcpy(dest, src, len);
		break;

	case SSH_CIPHER_3DES:
		SSH_3CBC_ENCRYPT(context->u.des3.key1,
				 context->u.des3.key2, &context->u.des3.iv2,
				 context->u.des3.key3, &context->u.des3.iv3,
				 dest, (unsigned char *) src, len);
		break;

	case SSH_CIPHER_BLOWFISH:
		swap_bytes(src, dest, len);
		BF_cbc_encrypt(dest, dest, len,
			       &context->u.bf.key, context->u.bf.iv,
			       BF_ENCRYPT);
		swap_bytes(dest, dest, len);
		break;

	case SSH_CIPHER_BLOWFISH_CBC:
		BF_cbc_encrypt((void *)src, dest, len,
			       &context->u.bf.key, context->u.bf.iv,
			       BF_ENCRYPT);
		break;

	case SSH_CIPHER_3DES_CBC:
		des_ede3_cbc_encrypt(src, dest, len,
		    context->u.des3.key1, context->u.des3.key2,
		    context->u.des3.key3, &context->u.des3.iv3, DES_ENCRYPT);
		break;

	case SSH_CIPHER_ARCFOUR:
		RC4(&context->u.rc4, len, (unsigned char *)src, dest);
		break;

	case SSH_CIPHER_CAST128_CBC:
		CAST_cbc_encrypt(src, dest, len,
		    &context->u.cast.key, context->u.cast.iv, CAST_ENCRYPT);
		break;

	default:
		fatal("cipher_encrypt: unknown cipher: %s", cipher_name(context->type));
	}
}

/* Decrypts data using the cipher. */

void
cipher_decrypt(CipherContext *context, unsigned char *dest,
	       const unsigned char *src, unsigned int len)
{
	if ((len & 7) != 0)
		fatal("cipher_decrypt: bad ciphertext length %d", len);

	switch (context->type) {
	case SSH_CIPHER_NONE:
		memcpy(dest, src, len);
		break;

	case SSH_CIPHER_3DES:
		SSH_3CBC_DECRYPT(context->u.des3.key1,
				 context->u.des3.key2, &context->u.des3.iv2,
				 context->u.des3.key3, &context->u.des3.iv3,
				 dest, (unsigned char *) src, len);
		break;

	case SSH_CIPHER_BLOWFISH:
		swap_bytes(src, dest, len);
		BF_cbc_encrypt((void *) dest, dest, len,
			       &context->u.bf.key, context->u.bf.iv,
			       BF_DECRYPT);
		swap_bytes(dest, dest, len);
		break;

	case SSH_CIPHER_BLOWFISH_CBC:
		BF_cbc_encrypt((void *) src, dest, len,
			       &context->u.bf.key, context->u.bf.iv,
			       BF_DECRYPT);
		break;

	case SSH_CIPHER_3DES_CBC:
		des_ede3_cbc_encrypt(src, dest, len,
		    context->u.des3.key1, context->u.des3.key2,
		    context->u.des3.key3, &context->u.des3.iv3, DES_DECRYPT);
		break;

	case SSH_CIPHER_ARCFOUR:
		RC4(&context->u.rc4, len, (unsigned char *)src, dest);
		break;

	case SSH_CIPHER_CAST128_CBC:
		CAST_cbc_encrypt(src, dest, len,
		    &context->u.cast.key, context->u.cast.iv, CAST_DECRYPT);
		break;

	default:
		fatal("cipher_decrypt: unknown cipher: %s", cipher_name(context->type));
	}
}
Commit	Line	Data
8efc0c15	1	/*
6ae2364d	2	*
5260325f	3	* cipher.c
6ae2364d	4	*
5260325f	5	* Author: Tatu Ylonen <ylo@cs.hut.fi>
6ae2364d	6	*
5260325f	7	* Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland
5260325f	8	* All rights reserved
6ae2364d	9	*
5260325f	10	* Created: Wed Apr 19 17:41:39 1995 ylo
6ae2364d	11	*
5260325f	12	*/
8efc0c15	13
8efc0c15	14	#include "includes.h"
089fbbd2	15	RCSID("$OpenBSD: cipher.c,v 1.29 2000/07/10 16:30:25 ho Exp $");
8efc0c15	16
	17	#include "ssh.h"
	18	#include "cipher.h"
a8be9f80	19	#include "xmalloc.h"
8efc0c15	20
	21	#include <openssl/md5.h>
	22
	23	/*
a8be9f80	24	* This is used by SSH1:
	25	*
	26	* What kind of triple DES are these 2 routines?
8efc0c15	27	*
	28	* Why is there a redundant initialization vector?
	29	*
	30	* If only iv3 was used, then, this would till effect have been
	31	* outer-cbc. However, there is also a private iv1 == iv2 which
	32	* perhaps makes differential analysis easier. On the other hand, the
	33	* private iv1 probably makes the CRC-32 attack ineffective. This is a
	34	* result of that there is no longer any known iv1 to use when
	35	* choosing the X block.
	36	*/
	37	void
	38	SSH_3CBC_ENCRYPT(des_key_schedule ks1,
5260325f	39	des_key_schedule ks2, des_cblock * iv2,
5260325f	40	des_key_schedule ks3, des_cblock * iv3,
c8d54615	41	unsigned char dest, unsigned char src,
8efc0c15	42	unsigned int len)
8efc0c15	43	{
5260325f	44	des_cblock iv1;
8efc0c15	45
5260325f	46	memcpy(&iv1, iv2, 8);
8efc0c15	47
5260325f	48	des_cbc_encrypt(src, dest, len, ks1, &iv1, DES_ENCRYPT);
c8d54615	49	memcpy(&iv1, dest + len - 8, 8);
8efc0c15	50
5260325f	51	des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_DECRYPT);
5260325f	52	memcpy(iv2, &iv1, 8); /* Note how iv1 == iv2 on entry and exit. */
8efc0c15	53
5260325f	54	des_cbc_encrypt(dest, dest, len, ks3, iv3, DES_ENCRYPT);
c8d54615	55	memcpy(iv3, dest + len - 8, 8);
8efc0c15	56	}
	57
	58	void
	59	SSH_3CBC_DECRYPT(des_key_schedule ks1,
5260325f	60	des_key_schedule ks2, des_cblock * iv2,
5260325f	61	des_key_schedule ks3, des_cblock * iv3,
c8d54615	62	unsigned char dest, unsigned char src,
8efc0c15	63	unsigned int len)
8efc0c15	64	{
5260325f	65	des_cblock iv1;
8efc0c15	66
5260325f	67	memcpy(&iv1, iv2, 8);
8efc0c15	68
5260325f	69	des_cbc_encrypt(src, dest, len, ks3, iv3, DES_DECRYPT);
c8d54615	70	memcpy(iv3, src + len - 8, 8);
8efc0c15	71
5260325f	72	des_cbc_encrypt(dest, dest, len, ks2, iv2, DES_ENCRYPT);
c8d54615	73	memcpy(iv2, dest + len - 8, 8);
8efc0c15	74
5260325f	75	des_cbc_encrypt(dest, dest, len, ks1, &iv1, DES_DECRYPT);
	76	/* memcpy(&iv1, iv2, 8); */
	77	/* Note how iv1 == iv2 on entry and exit. */
8efc0c15	78	}
	79
	80	/*
a8be9f80	81	* SSH1 uses a variation on Blowfish, all bytes must be swapped before
8efc0c15	82	* and after encryption/decryption. Thus the swap_bytes stuff (yuk).
8efc0c15	83	*/
5260325f	84	static void
8efc0c15	85	swap_bytes(const unsigned char src, unsigned char dst_, int n)
8efc0c15	86	{
5260325f	87	/* dst must be properly aligned. */
	88	u_int32_t dst = (u_int32_t ) dst_;
	89	union {
	90	u_int32_t i;
	91	char c[4];
	92	} t;
	93
	94	/* Process 8 bytes every lap. */
	95	for (n = n / 8; n > 0; n--) {
	96	t.c[3] = *src++;
	97	t.c[2] = *src++;
	98	t.c[1] = *src++;
	99	t.c[0] = *src++;
	100	*dst++ = t.i;
	101
	102	t.c[3] = *src++;
	103	t.c[2] = *src++;
	104	t.c[1] = *src++;
	105	t.c[0] = *src++;
	106	*dst++ = t.i;
	107	}
8efc0c15	108	}
8efc0c15	109
aa3378df	110	/*
	111	* Names of all encryption algorithms.
	112	* These must match the numbers defined in cipher.h.
	113	*/
8efc0c15	114	static char *cipher_names[] =
8efc0c15	115	{
5260325f	116	"none",
	117	"idea",
	118	"des",
	119	"3des",
	120	"tss",
	121	"rc4",
7368a6c8	122	"blowfish",
	123	"reserved",
	124	"blowfish-cbc",
	125	"3des-cbc",
	126	"arcfour",
	127	"cast128-cbc"
8efc0c15	128	};
8efc0c15	129
aa3378df	130	/*
	131	* Returns a bit mask indicating which ciphers are supported by this
	132	* implementation. The bit mask has the corresponding bit set of each
	133	* supported cipher.
	134	*/
8efc0c15	135
6ae2364d	136	unsigned int
8ce64345	137	cipher_mask1()
8efc0c15	138	{
5260325f	139	unsigned int mask = 0;
	140	mask \|= 1 << SSH_CIPHER_3DES; /* Mandatory */
	141	mask \|= 1 << SSH_CIPHER_BLOWFISH;
8ce64345	142	return mask;
8ce64345	143	}
6ae2364d	144	unsigned int
8ce64345	145	cipher_mask2()
	146	{
	147	unsigned int mask = 0;
7368a6c8	148	mask \|= 1 << SSH_CIPHER_BLOWFISH_CBC;
	149	mask \|= 1 << SSH_CIPHER_3DES_CBC;
	150	mask \|= 1 << SSH_CIPHER_ARCFOUR;
	151	mask \|= 1 << SSH_CIPHER_CAST128_CBC;
5260325f	152	return mask;
8efc0c15	153	}
6ae2364d	154	unsigned int
8ce64345	155	cipher_mask()
	156	{
	157	return cipher_mask1() \| cipher_mask2();
	158	}
8efc0c15	159
	160	/* Returns the name of the cipher. */
	161
5260325f	162	const char *
5260325f	163	cipher_name(int cipher)
8efc0c15	164	{
5260325f	165	if (cipher < 0 \|\| cipher >= sizeof(cipher_names) / sizeof(cipher_names[0]) \|\|
5260325f	166	cipher_names[cipher] == NULL)
a8be9f80	167	fatal("cipher_name: bad cipher name: %d", cipher);
5260325f	168	return cipher_names[cipher];
8efc0c15	169	}
8efc0c15	170
a8be9f80	171	/* Returns 1 if the name of the ciphers are valid. */
	172
	173	#define CIPHER_SEP ","
	174	int
	175	ciphers_valid(const char *names)
	176	{
089fbbd2	177	char ciphers, cp;
a8be9f80	178	char *p;
	179	int i;
	180
71276795	181	if (names == NULL \|\| strcmp(names, "") == 0)
a8be9f80	182	return 0;
089fbbd2	183	ciphers = cp = xstrdup(names);
	184	for ((p = strsep(&cp, CIPHER_SEP)); p && *p != '\0';
	185	(p = strsep(&cp, CIPHER_SEP))) {
a8be9f80	186	i = cipher_number(p);
	187	if (i == -1 \|\| !(cipher_mask2() & (1 << i))) {
	188	xfree(ciphers);
	189	return 0;
	190	}
	191	}
	192	xfree(ciphers);
	193	return 1;
	194	}
	195
aa3378df	196	/*
	197	* Parses the name of the cipher. Returns the number of the corresponding
	198	* cipher, or -1 on error.
	199	*/
8efc0c15	200
	201	int
	202	cipher_number(const char *name)
	203	{
5260325f	204	int i;
71276795	205	if (name == NULL)
71276795	206	return -1;
5260325f	207	for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++)
	208	if (strcmp(cipher_names[i], name) == 0 &&
	209	(cipher_mask() & (1 << i)))
	210	return i;
	211	return -1;
8efc0c15	212	}
8efc0c15	213
aa3378df	214	/*
	215	* Selects the cipher, and keys if by computing the MD5 checksum of the
	216	* passphrase and using the resulting 16 bytes as the key.
	217	*/
8efc0c15	218
6ae2364d	219	void
8ce64345	220	cipher_set_key_string(CipherContext context, int cipher, const char passphrase)
8efc0c15	221	{
5260325f	222	MD5_CTX md;
	223	unsigned char digest[16];
	224
	225	MD5_Init(&md);
	226	MD5_Update(&md, (const unsigned char *) passphrase, strlen(passphrase));
	227	MD5_Final(digest, &md);
	228
8ce64345	229	cipher_set_key(context, cipher, digest, 16);
5260325f	230
	231	memset(digest, 0, sizeof(digest));
	232	memset(&md, 0, sizeof(md));
8efc0c15	233	}
	234
	235	/* Selects the cipher to use and sets the key. */
	236
6ae2364d	237	void
8ce64345	238	cipher_set_key(CipherContext context, int cipher, const unsigned char key,
8ce64345	239	int keylen)
8efc0c15	240	{
5260325f	241	unsigned char padded[32];
	242
	243	/* Set cipher type. */
	244	context->type = cipher;
	245
	246	/* Get 32 bytes of key data. Pad if necessary. (So that code
	247	below does not need to worry about key size). */
	248	memset(padded, 0, sizeof(padded));
	249	memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded));
	250
	251	/* Initialize the initialization vector. */
	252	switch (cipher) {
	253	case SSH_CIPHER_NONE:
aa3378df	254	/*
	255	* Has to stay for authfile saving of private key with no
	256	* passphrase
	257	*/
5260325f	258	break;
	259
	260	case SSH_CIPHER_3DES:
aa3378df	261	/*
	262	* Note: the least significant bit of each byte of key is
	263	* parity, and must be ignored by the implementation. 16
	264	* bytes of key are used (first and last keys are the same).
	265	*/
5260325f	266	if (keylen < 16)
	267	error("Key length %d is insufficient for 3DES.", keylen);
	268	des_set_key((void *) padded, context->u.des3.key1);
	269	des_set_key((void *) (padded + 8), context->u.des3.key2);
	270	if (keylen <= 16)
	271	des_set_key((void *) padded, context->u.des3.key3);
	272	else
	273	des_set_key((void *) (padded + 16), context->u.des3.key3);
	274	memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2));
	275	memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3));
	276	break;
	277
	278	case SSH_CIPHER_BLOWFISH:
7368a6c8	279	if (keylen < 16)
7368a6c8	280	error("Key length %d is insufficient for blowfish.", keylen);
5260325f	281	BF_set_key(&context->u.bf.key, keylen, padded);
	282	memset(context->u.bf.iv, 0, 8);
	283	break;
	284
7368a6c8	285	case SSH_CIPHER_3DES_CBC:
	286	case SSH_CIPHER_BLOWFISH_CBC:
	287	case SSH_CIPHER_ARCFOUR:
	288	case SSH_CIPHER_CAST128_CBC:
	289	fatal("cipher_set_key: illegal cipher: %s", cipher_name(cipher));
	290	break;
	291
5260325f	292	default:
	293	fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
	294	}
	295	memset(padded, 0, sizeof(padded));
8efc0c15	296	}
8efc0c15	297
6ae2364d	298	void
7368a6c8	299	cipher_set_key_iv(CipherContext * context, int cipher,
6ae2364d	300	const unsigned char *key, int keylen,
7368a6c8	301	const unsigned char *iv, int ivlen)
	302	{
	303	/* Set cipher type. */
	304	context->type = cipher;
	305
	306	/* Initialize the initialization vector. */
	307	switch (cipher) {
	308	case SSH_CIPHER_NONE:
	309	break;
	310
	311	case SSH_CIPHER_3DES:
	312	case SSH_CIPHER_BLOWFISH:
	313	fatal("cipher_set_key_iv: illegal cipher: %s", cipher_name(cipher));
	314	break;
	315
	316	case SSH_CIPHER_3DES_CBC:
	317	if (keylen < 24)
	318	error("Key length %d is insufficient for 3des-cbc.", keylen);
	319	des_set_key((void *) key, context->u.des3.key1);
	320	des_set_key((void *) (key+8), context->u.des3.key2);
	321	des_set_key((void *) (key+16), context->u.des3.key3);
	322	if (ivlen < 8)
	323	error("IV length %d is insufficient for 3des-cbc.", ivlen);
	324	memcpy(context->u.des3.iv3, (char *)iv, 8);
	325	break;
	326
	327	case SSH_CIPHER_BLOWFISH_CBC:
	328	if (keylen < 16)
	329	error("Key length %d is insufficient for blowfish.", keylen);
	330	if (ivlen < 8)
	331	error("IV length %d is insufficient for blowfish.", ivlen);
	332	BF_set_key(&context->u.bf.key, keylen, (unsigned char *)key);
	333	memcpy(context->u.bf.iv, (char *)iv, 8);
	334	break;
	335
	336	case SSH_CIPHER_ARCFOUR:
	337	if (keylen < 16)
	338	error("Key length %d is insufficient for arcfour.", keylen);
	339	RC4_set_key(&context->u.rc4, keylen, (unsigned char *)key);
	340	break;
	341
	342	case SSH_CIPHER_CAST128_CBC:
	343	if (keylen < 16)
	344	error("Key length %d is insufficient for cast128.", keylen);
	345	if (ivlen < 8)
	346	error("IV length %d is insufficient for cast128.", ivlen);
	347	CAST_set_key(&context->u.cast.key, keylen, (unsigned char *) key);
	348	memcpy(context->u.cast.iv, (char *)iv, 8);
	349	break;
	350
	351	default:
	352	fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
	353	}
	354	}
	355
8efc0c15	356	/* Encrypts data using the cipher. */
8efc0c15	357
6ae2364d	358	void
5260325f	359	cipher_encrypt(CipherContext context, unsigned char dest,
5260325f	360	const unsigned char *src, unsigned int len)
8efc0c15	361	{
5260325f	362	if ((len & 7) != 0)
	363	fatal("cipher_encrypt: bad plaintext length %d", len);
	364
	365	switch (context->type) {
	366	case SSH_CIPHER_NONE:
	367	memcpy(dest, src, len);
	368	break;
	369
	370	case SSH_CIPHER_3DES:
	371	SSH_3CBC_ENCRYPT(context->u.des3.key1,
	372	context->u.des3.key2, &context->u.des3.iv2,
	373	context->u.des3.key3, &context->u.des3.iv3,
c8d54615	374	dest, (unsigned char *) src, len);
5260325f	375	break;
	376
	377	case SSH_CIPHER_BLOWFISH:
	378	swap_bytes(src, dest, len);
	379	BF_cbc_encrypt(dest, dest, len,
6ae2364d	380	&context->u.bf.key, context->u.bf.iv,
5260325f	381	BF_ENCRYPT);
	382	swap_bytes(dest, dest, len);
	383	break;
	384
7368a6c8	385	case SSH_CIPHER_BLOWFISH_CBC:
7368a6c8	386	BF_cbc_encrypt((void *)src, dest, len,
6ae2364d	387	&context->u.bf.key, context->u.bf.iv,
7368a6c8	388	BF_ENCRYPT);
	389	break;
	390
	391	case SSH_CIPHER_3DES_CBC:
	392	des_ede3_cbc_encrypt(src, dest, len,
	393	context->u.des3.key1, context->u.des3.key2,
	394	context->u.des3.key3, &context->u.des3.iv3, DES_ENCRYPT);
	395	break;
	396
	397	case SSH_CIPHER_ARCFOUR:
	398	RC4(&context->u.rc4, len, (unsigned char *)src, dest);
	399	break;
	400
	401	case SSH_CIPHER_CAST128_CBC:
	402	CAST_cbc_encrypt(src, dest, len,
	403	&context->u.cast.key, context->u.cast.iv, CAST_ENCRYPT);
	404	break;
	405
5260325f	406	default:
	407	fatal("cipher_encrypt: unknown cipher: %s", cipher_name(context->type));
	408	}
8efc0c15	409	}
5260325f	410
8efc0c15	411	/* Decrypts data using the cipher. */
8efc0c15	412
6ae2364d	413	void
5260325f	414	cipher_decrypt(CipherContext context, unsigned char dest,
5260325f	415	const unsigned char *src, unsigned int len)
8efc0c15	416	{
5260325f	417	if ((len & 7) != 0)
	418	fatal("cipher_decrypt: bad ciphertext length %d", len);
	419
	420	switch (context->type) {
	421	case SSH_CIPHER_NONE:
	422	memcpy(dest, src, len);
	423	break;
	424
	425	case SSH_CIPHER_3DES:
5260325f	426	SSH_3CBC_DECRYPT(context->u.des3.key1,
	427	context->u.des3.key2, &context->u.des3.iv2,
	428	context->u.des3.key3, &context->u.des3.iv3,
c8d54615	429	dest, (unsigned char *) src, len);
5260325f	430	break;
	431
	432	case SSH_CIPHER_BLOWFISH:
5260325f	433	swap_bytes(src, dest, len);
	434	BF_cbc_encrypt((void *) dest, dest, len,
	435	&context->u.bf.key, context->u.bf.iv,
	436	BF_DECRYPT);
	437	swap_bytes(dest, dest, len);
	438	break;
	439
7368a6c8	440	case SSH_CIPHER_BLOWFISH_CBC:
	441	BF_cbc_encrypt((void *) src, dest, len,
	442	&context->u.bf.key, context->u.bf.iv,
	443	BF_DECRYPT);
	444	break;
	445
	446	case SSH_CIPHER_3DES_CBC:
	447	des_ede3_cbc_encrypt(src, dest, len,
	448	context->u.des3.key1, context->u.des3.key2,
	449	context->u.des3.key3, &context->u.des3.iv3, DES_DECRYPT);
	450	break;
	451
	452	case SSH_CIPHER_ARCFOUR:
	453	RC4(&context->u.rc4, len, (unsigned char *)src, dest);
	454	break;
	455
	456	case SSH_CIPHER_CAST128_CBC:
	457	CAST_cbc_encrypt(src, dest, len,
	458	&context->u.cast.key, context->u.cast.iv, CAST_DECRYPT);
	459	break;
	460
5260325f	461	default:
	462	fatal("cipher_decrypt: unknown cipher: %s", cipher_name(context->type));
	463	}
8efc0c15	464	}