[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("$Id$");

#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;
	char *p;
	int i;

	if (strcmp(names, "") == 0)
		return 0;
	ciphers = xstrdup(names);
	for ((p = strtok(ciphers, CIPHER_SEP)); p; (p = strtok(NULL, 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;
	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
	14	#include "includes.h"
	15	RCSID("$Id$");
	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	{
	177	char *ciphers;
	178	char *p;
	179	int i;
	180
	181	if (strcmp(names, "") == 0)
	182	return 0;
	183	ciphers = xstrdup(names);
	184	for ((p = strtok(ciphers, CIPHER_SEP)); p; (p = strtok(NULL, CIPHER_SEP))) {
	185	i = cipher_number(p);
	186	if (i == -1 \|\| !(cipher_mask2() & (1 << i))) {
	187	xfree(ciphers);
	188	return 0;
	189	}
	190	}
	191	xfree(ciphers);
	192	return 1;
	193	}
	194
aa3378df	195	/*
	196	* Parses the name of the cipher. Returns the number of the corresponding
	197	* cipher, or -1 on error.
	198	*/
8efc0c15	199
	200	int
	201	cipher_number(const char *name)
	202	{
5260325f	203	int i;
	204	for (i = 0; i < sizeof(cipher_names) / sizeof(cipher_names[0]); i++)
	205	if (strcmp(cipher_names[i], name) == 0 &&
	206	(cipher_mask() & (1 << i)))
	207	return i;
	208	return -1;
8efc0c15	209	}
8efc0c15	210
aa3378df	211	/*
	212	* Selects the cipher, and keys if by computing the MD5 checksum of the
	213	* passphrase and using the resulting 16 bytes as the key.
	214	*/
8efc0c15	215
6ae2364d	216	void
8ce64345	217	cipher_set_key_string(CipherContext context, int cipher, const char passphrase)
8efc0c15	218	{
5260325f	219	MD5_CTX md;
	220	unsigned char digest[16];
	221
	222	MD5_Init(&md);
	223	MD5_Update(&md, (const unsigned char *) passphrase, strlen(passphrase));
	224	MD5_Final(digest, &md);
	225
8ce64345	226	cipher_set_key(context, cipher, digest, 16);
5260325f	227
	228	memset(digest, 0, sizeof(digest));
	229	memset(&md, 0, sizeof(md));
8efc0c15	230	}
	231
	232	/* Selects the cipher to use and sets the key. */
	233
6ae2364d	234	void
8ce64345	235	cipher_set_key(CipherContext context, int cipher, const unsigned char key,
8ce64345	236	int keylen)
8efc0c15	237	{
5260325f	238	unsigned char padded[32];
	239
	240	/* Set cipher type. */
	241	context->type = cipher;
	242
	243	/* Get 32 bytes of key data. Pad if necessary. (So that code
	244	below does not need to worry about key size). */
	245	memset(padded, 0, sizeof(padded));
	246	memcpy(padded, key, keylen < sizeof(padded) ? keylen : sizeof(padded));
	247
	248	/* Initialize the initialization vector. */
	249	switch (cipher) {
	250	case SSH_CIPHER_NONE:
aa3378df	251	/*
	252	* Has to stay for authfile saving of private key with no
	253	* passphrase
	254	*/
5260325f	255	break;
	256
	257	case SSH_CIPHER_3DES:
aa3378df	258	/*
	259	* Note: the least significant bit of each byte of key is
	260	* parity, and must be ignored by the implementation. 16
	261	* bytes of key are used (first and last keys are the same).
	262	*/
5260325f	263	if (keylen < 16)
	264	error("Key length %d is insufficient for 3DES.", keylen);
	265	des_set_key((void *) padded, context->u.des3.key1);
	266	des_set_key((void *) (padded + 8), context->u.des3.key2);
	267	if (keylen <= 16)
	268	des_set_key((void *) padded, context->u.des3.key3);
	269	else
	270	des_set_key((void *) (padded + 16), context->u.des3.key3);
	271	memset(context->u.des3.iv2, 0, sizeof(context->u.des3.iv2));
	272	memset(context->u.des3.iv3, 0, sizeof(context->u.des3.iv3));
	273	break;
	274
	275	case SSH_CIPHER_BLOWFISH:
7368a6c8	276	if (keylen < 16)
7368a6c8	277	error("Key length %d is insufficient for blowfish.", keylen);
5260325f	278	BF_set_key(&context->u.bf.key, keylen, padded);
	279	memset(context->u.bf.iv, 0, 8);
	280	break;
	281
7368a6c8	282	case SSH_CIPHER_3DES_CBC:
	283	case SSH_CIPHER_BLOWFISH_CBC:
	284	case SSH_CIPHER_ARCFOUR:
	285	case SSH_CIPHER_CAST128_CBC:
	286	fatal("cipher_set_key: illegal cipher: %s", cipher_name(cipher));
	287	break;
	288
5260325f	289	default:
	290	fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
	291	}
	292	memset(padded, 0, sizeof(padded));
8efc0c15	293	}
8efc0c15	294
6ae2364d	295	void
7368a6c8	296	cipher_set_key_iv(CipherContext * context, int cipher,
6ae2364d	297	const unsigned char *key, int keylen,
7368a6c8	298	const unsigned char *iv, int ivlen)
	299	{
	300	/* Set cipher type. */
	301	context->type = cipher;
	302
	303	/* Initialize the initialization vector. */
	304	switch (cipher) {
	305	case SSH_CIPHER_NONE:
	306	break;
	307
	308	case SSH_CIPHER_3DES:
	309	case SSH_CIPHER_BLOWFISH:
	310	fatal("cipher_set_key_iv: illegal cipher: %s", cipher_name(cipher));
	311	break;
	312
	313	case SSH_CIPHER_3DES_CBC:
	314	if (keylen < 24)
	315	error("Key length %d is insufficient for 3des-cbc.", keylen);
	316	des_set_key((void *) key, context->u.des3.key1);
	317	des_set_key((void *) (key+8), context->u.des3.key2);
	318	des_set_key((void *) (key+16), context->u.des3.key3);
	319	if (ivlen < 8)
	320	error("IV length %d is insufficient for 3des-cbc.", ivlen);
	321	memcpy(context->u.des3.iv3, (char *)iv, 8);
	322	break;
	323
	324	case SSH_CIPHER_BLOWFISH_CBC:
	325	if (keylen < 16)
	326	error("Key length %d is insufficient for blowfish.", keylen);
	327	if (ivlen < 8)
	328	error("IV length %d is insufficient for blowfish.", ivlen);
	329	BF_set_key(&context->u.bf.key, keylen, (unsigned char *)key);
	330	memcpy(context->u.bf.iv, (char *)iv, 8);
	331	break;
	332
	333	case SSH_CIPHER_ARCFOUR:
	334	if (keylen < 16)
	335	error("Key length %d is insufficient for arcfour.", keylen);
	336	RC4_set_key(&context->u.rc4, keylen, (unsigned char *)key);
	337	break;
	338
	339	case SSH_CIPHER_CAST128_CBC:
	340	if (keylen < 16)
	341	error("Key length %d is insufficient for cast128.", keylen);
	342	if (ivlen < 8)
	343	error("IV length %d is insufficient for cast128.", ivlen);
	344	CAST_set_key(&context->u.cast.key, keylen, (unsigned char *) key);
	345	memcpy(context->u.cast.iv, (char *)iv, 8);
	346	break;
	347
	348	default:
	349	fatal("cipher_set_key: unknown cipher: %s", cipher_name(cipher));
	350	}
	351	}
	352
8efc0c15	353	/* Encrypts data using the cipher. */
8efc0c15	354
6ae2364d	355	void
5260325f	356	cipher_encrypt(CipherContext context, unsigned char dest,
5260325f	357	const unsigned char *src, unsigned int len)
8efc0c15	358	{
5260325f	359	if ((len & 7) != 0)
	360	fatal("cipher_encrypt: bad plaintext length %d", len);
	361
	362	switch (context->type) {
	363	case SSH_CIPHER_NONE:
	364	memcpy(dest, src, len);
	365	break;
	366
	367	case SSH_CIPHER_3DES:
	368	SSH_3CBC_ENCRYPT(context->u.des3.key1,
	369	context->u.des3.key2, &context->u.des3.iv2,
	370	context->u.des3.key3, &context->u.des3.iv3,
c8d54615	371	dest, (unsigned char *) src, len);
5260325f	372	break;
	373
	374	case SSH_CIPHER_BLOWFISH:
	375	swap_bytes(src, dest, len);
	376	BF_cbc_encrypt(dest, dest, len,
6ae2364d	377	&context->u.bf.key, context->u.bf.iv,
5260325f	378	BF_ENCRYPT);
	379	swap_bytes(dest, dest, len);
	380	break;
	381
7368a6c8	382	case SSH_CIPHER_BLOWFISH_CBC:
7368a6c8	383	BF_cbc_encrypt((void *)src, dest, len,
6ae2364d	384	&context->u.bf.key, context->u.bf.iv,
7368a6c8	385	BF_ENCRYPT);
	386	break;
	387
	388	case SSH_CIPHER_3DES_CBC:
	389	des_ede3_cbc_encrypt(src, dest, len,
	390	context->u.des3.key1, context->u.des3.key2,
	391	context->u.des3.key3, &context->u.des3.iv3, DES_ENCRYPT);
	392	break;
	393
	394	case SSH_CIPHER_ARCFOUR:
	395	RC4(&context->u.rc4, len, (unsigned char *)src, dest);
	396	break;
	397
	398	case SSH_CIPHER_CAST128_CBC:
	399	CAST_cbc_encrypt(src, dest, len,
	400	&context->u.cast.key, context->u.cast.iv, CAST_ENCRYPT);
	401	break;
	402
5260325f	403	default:
	404	fatal("cipher_encrypt: unknown cipher: %s", cipher_name(context->type));
	405	}
8efc0c15	406	}
5260325f	407
8efc0c15	408	/* Decrypts data using the cipher. */
8efc0c15	409
6ae2364d	410	void
5260325f	411	cipher_decrypt(CipherContext context, unsigned char dest,
5260325f	412	const unsigned char *src, unsigned int len)
8efc0c15	413	{
5260325f	414	if ((len & 7) != 0)
	415	fatal("cipher_decrypt: bad ciphertext length %d", len);
	416
	417	switch (context->type) {
	418	case SSH_CIPHER_NONE:
	419	memcpy(dest, src, len);
	420	break;
	421
	422	case SSH_CIPHER_3DES:
5260325f	423	SSH_3CBC_DECRYPT(context->u.des3.key1,
	424	context->u.des3.key2, &context->u.des3.iv2,
	425	context->u.des3.key3, &context->u.des3.iv3,
c8d54615	426	dest, (unsigned char *) src, len);
5260325f	427	break;
	428
	429	case SSH_CIPHER_BLOWFISH:
5260325f	430	swap_bytes(src, dest, len);
	431	BF_cbc_encrypt((void *) dest, dest, len,
	432	&context->u.bf.key, context->u.bf.iv,
	433	BF_DECRYPT);
	434	swap_bytes(dest, dest, len);
	435	break;
	436
7368a6c8	437	case SSH_CIPHER_BLOWFISH_CBC:
	438	BF_cbc_encrypt((void *) src, dest, len,
	439	&context->u.bf.key, context->u.bf.iv,
	440	BF_DECRYPT);
	441	break;
	442
	443	case SSH_CIPHER_3DES_CBC:
	444	des_ede3_cbc_encrypt(src, dest, len,
	445	context->u.des3.key1, context->u.des3.key2,
	446	context->u.des3.key3, &context->u.des3.iv3, DES_DECRYPT);
	447	break;
	448
	449	case SSH_CIPHER_ARCFOUR:
	450	RC4(&context->u.rc4, len, (unsigned char *)src, dest);
	451	break;
	452
	453	case SSH_CIPHER_CAST128_CBC:
	454	CAST_cbc_encrypt(src, dest, len,
	455	&context->u.cast.key, context->u.cast.iv, CAST_DECRYPT);
	456	break;
	457
5260325f	458	default:
	459	fatal("cipher_decrypt: unknown cipher: %s", cipher_name(context->type));
	460	}
8efc0c15	461	}