source: trunk/third/openssh/cipher.c @ 18759

/*
 * 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 1.61 2002/07/12 15:50:17 markus Exp $");

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

#include <openssl/md5.h>

#if OPENSSL_VERSION_NUMBER < 0x00906000L
#define SSH_OLD_EVP
#define EVP_CIPHER_CTX_get_app_data(e)          ((e)->app_data)
#endif

#if OPENSSL_VERSION_NUMBER < 0x00907000L
#include "rijndael.h"
static const EVP_CIPHER *evp_rijndael(void);
#endif
static const EVP_CIPHER *evp_ssh1_3des(void);
static const EVP_CIPHER *evp_ssh1_bf(void);

struct Cipher {
        char    *name;
        int     number;         /* for ssh1 only */
        u_int   block_size;
        u_int   key_len;
        const 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 },
#if OPENSSL_VERSION_NUMBER < 0x00907000L
        { "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 },
#else
        { "aes128-cbc",         SSH_CIPHER_SSH2, 16, 16, EVP_aes_128_cbc },
        { "aes192-cbc",         SSH_CIPHER_SSH2, 16, 24, EVP_aes_192_cbc },
        { "aes256-cbc",         SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
        { "rijndael-cbc@lysator.liu.se",
                                SSH_CIPHER_SSH2, 16, 32, EVP_aes_256_cbc },
#endif

        { 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 const 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];
        }
}

#ifdef SSH_OLD_EVP
static void bf_ssh1_init (EVP_CIPHER_CTX * ctx, const unsigned char *key,
                          const unsigned char *iv, int enc)
{
        if (iv != NULL)
                memcpy (&(ctx->oiv[0]), iv, 8);
        memcpy (&(ctx->iv[0]), &(ctx->oiv[0]), 8);
        if (key != NULL)
                BF_set_key (&(ctx->c.bf_ks), EVP_CIPHER_CTX_key_length (ctx),
                            key);
}
#endif
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 const 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;
#ifdef SSH_OLD_EVP
        ssh1_bf.init = bf_ssh1_init;
#endif
        ssh1_bf.do_cipher = bf_ssh1_cipher;
        ssh1_bf.key_len = 32;
        return (&ssh1_bf);
}

#if OPENSSL_VERSION_NUMBER < 0x00907000L
/* 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 const 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 | EVP_CIPH_CUSTOM_IV;
#endif
        return (&rijndal_cbc);
}
#endif

/*
 * 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", __func__,
                            evplen, len);

#if OPENSSL_VERSION_NUMBER < 0x00907000L
                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", __func__);
                        civ = aesc->r_iv;
                } else
#endif
                {
                        civ = cc->evp.iv;
                }
                break;
        case SSH_CIPHER_3DES: {
                struct ssh1_3des_ctx *desc;
                if (len != 24)
                        fatal("%s: bad 3des iv length: %d", __func__, len);
                desc = EVP_CIPHER_CTX_get_app_data(&cc->evp);
                if (desc == NULL)
                        fatal("%s: no 3des context", __func__);
                debug3("%s: Copying 3DES IV", __func__);
                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", __func__, 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 OPENSSL_VERSION_NUMBER < 0x00907000L
                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", __func__);
                        div = aesc->r_iv;
                } else
#endif
                {
                        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", __func__);
                debug3("%s: Installed 3DES IV", __func__);
                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", __func__, 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 = 0;

        if (c->evptype == EVP_rc4) {
                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) {
                plen = EVP_X_STATE_LEN(cc->evp);
                memcpy(EVP_X_STATE(cc->evp), dat, plen);
        }
}