ttssh2/ttxssh/cipher-ctr.c

/*
 * Import from OpenSSH  (TeraTerm Project 2008.11.18)
 */
/* $OpenBSD: cipher-ctr.c,v 1.10 2006/08/03 03:34:42 deraadt Exp $ */
/*
 * Copyright (c) 2003 Markus Friedl <markus@openbsd.org>
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
#include <sys/types.h>
#include <malloc.h>
#include <string.h>

#include "config.h"

#include <openssl/evp.h>
#include <openssl/aes.h>
#include <openssl/des.h>
#include <openssl/blowfish.h>
#include <openssl/cast.h>
#include <openssl/camellia.h>

extern const EVP_CIPHER *evp_aes_128_ctr(void);
extern const EVP_CIPHER *evp_camellia_128_ctr(void);

struct ssh_aes_ctr_ctx
{
        AES_KEY         aes_ctx;
        unsigned char   aes_counter[AES_BLOCK_SIZE];
};

#define DES_BLOCK_SIZE sizeof(DES_cblock)
struct ssh_des3_ctr_ctx
{
        DES_key_schedule des3_ctx[3];
        unsigned char   des3_counter[DES_BLOCK_SIZE];
};

struct ssh_blowfish_ctr_ctx
{
        BF_KEY          blowfish_ctx;
        unsigned char   blowfish_counter[BF_BLOCK];
};

struct ssh_cast5_ctr_ctx
{
        CAST_KEY        cast5_ctx;
        unsigned char   cast5_counter[CAST_BLOCK];
};

struct ssh_camellia_ctr_ctx
{
        CAMELLIA_KEY    camellia_ctx;
        unsigned char   camellia_counter[CAMELLIA_BLOCK_SIZE];
};

static void
ssh_ctr_inc(unsigned char *ctr, unsigned int len)
{
        int i;

        for ( i = len - 1; i>= 0; i--)
                if (++ctr[i])
                        return;
}

//============================================================================
// AES
//============================================================================
static int
ssh_aes_ctr(EVP_CIPHER_CTX *ctx, unsigned char *dest, const unsigned char *src, unsigned int len)
{
        struct ssh_aes_ctr_ctx *c;
        unsigned int n = 0;
        unsigned char buf[AES_BLOCK_SIZE];

        if (len == 0)
                return (1);
        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL)
                return (0);

        while ((len--) > 0) {
                if (n == 0) {
                        AES_encrypt(c->aes_counter, buf, &c->aes_ctx);
                        ssh_ctr_inc(c->aes_counter, AES_BLOCK_SIZE);
                }
                *(dest++) = *(src++) ^ buf[n];
                n = (n + 1) % AES_BLOCK_SIZE;
        }
        return (1);
}

static int
ssh_aes_ctr_init(EVP_CIPHER_CTX *ctx, const unsigned char *key, const unsigned char *iv, int enc)
{
        struct ssh_aes_ctr_ctx *c;

        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
                c = malloc(sizeof(*c));
                EVP_CIPHER_CTX_set_app_data(ctx, c);
        }
        if (key != NULL)
                AES_set_encrypt_key(key, EVP_CIPHER_CTX_key_length(ctx) * 8, &c->aes_ctx);
        if (iv != NULL)
                memcpy(c->aes_counter, iv, AES_BLOCK_SIZE);
        return (1);
}

static int
ssh_aes_ctr_cleanup(EVP_CIPHER_CTX *ctx)
{
        struct ssh_aes_ctr_ctx *c;

        if((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
                memset(c, 0, sizeof(*c));
                free(c);
                EVP_CIPHER_CTX_set_app_data(ctx, NULL);
        }
        return (1);
}

const EVP_CIPHER *
evp_aes_128_ctr(void)
{
        static EVP_CIPHER aes_ctr;

        memset(&aes_ctr, 0, sizeof(EVP_CIPHER));
        aes_ctr.nid = NID_undef;
        aes_ctr.block_size = AES_BLOCK_SIZE;
        aes_ctr.iv_len = AES_BLOCK_SIZE;
        aes_ctr.key_len = 16;
        aes_ctr.init = ssh_aes_ctr_init;
        aes_ctr.cleanup = ssh_aes_ctr_cleanup;
        aes_ctr.do_cipher = ssh_aes_ctr;
#ifndef SSH_OLD_EVP
        aes_ctr.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH | EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV;
#endif
        return (&aes_ctr);
}

//============================================================================
// Triple-DES
//============================================================================
static int
ssh_des3_ctr(EVP_CIPHER_CTX *ctx, unsigned char *dest, const unsigned char *src, unsigned int len)
{
        struct ssh_des3_ctr_ctx *c;
        unsigned int n = 0;
        unsigned char buf[DES_BLOCK_SIZE];

        if (len == 0)
                return (1);
        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL)
                return (0);

        while ((len--) > 0) {
                if (n == 0) {
                        memcpy(buf, (unsigned char *)(c->des3_counter), DES_BLOCK_SIZE);
                        DES_encrypt3((DES_LONG *)buf, &c->des3_ctx[0], &c->des3_ctx[1], &c->des3_ctx[2]);
                        ssh_ctr_inc(c->des3_counter, DES_BLOCK_SIZE);
                }
                *(dest++) = *(src++) ^ buf[n];
                n = (n + 1) % DES_BLOCK_SIZE;
        }
        return (1);
}

static int
ssh_des3_ctr_init(EVP_CIPHER_CTX *ctx, const unsigned char *key, const unsigned char *iv, int enc)
{
        struct ssh_des3_ctr_ctx *c;

        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
                c = malloc(sizeof(*c));
                EVP_CIPHER_CTX_set_app_data(ctx, c);
        }
        if (key != NULL) {
                DES_set_key((const_DES_cblock *)key, &c->des3_ctx[0]);
                DES_set_key((const_DES_cblock *)(key + 8), &c->des3_ctx[1]);
                DES_set_key((const_DES_cblock *)(key + 16), &c->des3_ctx[2]);
        }

        if (iv != NULL)
                memcpy(c->des3_counter, iv, DES_BLOCK_SIZE);
        return (1);
}

static int
ssh_des3_ctr_cleanup(EVP_CIPHER_CTX *ctx)
{
        struct ssh_des3_ctr_ctx *c;

        if((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
                memset(c, 0, sizeof(*c));
                free(c);
                EVP_CIPHER_CTX_set_app_data(ctx, NULL);
        }
        return (1);
}

const EVP_CIPHER *
evp_des3_ctr(void)
{
        static EVP_CIPHER des3_ctr;

        memset(&des3_ctr, 0, sizeof(EVP_CIPHER));
        des3_ctr.nid = NID_undef;
        des3_ctr.block_size = DES_BLOCK_SIZE;
        des3_ctr.iv_len = DES_BLOCK_SIZE;
        des3_ctr.key_len = 24;
        des3_ctr.init = ssh_des3_ctr_init;
        des3_ctr.cleanup = ssh_des3_ctr_cleanup;
        des3_ctr.do_cipher = ssh_des3_ctr;
#ifndef SSH_OLD_EVP
        des3_ctr.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH | EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV;
#endif
        return (&des3_ctr);
}

//============================================================================
// Blowfish
//============================================================================
static int
ssh_bf_ctr(EVP_CIPHER_CTX *ctx, unsigned char *dest, const unsigned char *src, unsigned int len)
{
        struct ssh_blowfish_ctr_ctx *c;
        unsigned int n = 0;
        unsigned char buf[BF_BLOCK];
        int i, j;
        BF_LONG tmp[(BF_BLOCK + 3) / 4];
        unsigned char *p;

        if (len == 0)
                return (1);
        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL)
                return (0);

        while ((len--) > 0) {
                if (n == 0) {
                        for (i = j = 0, p = c->blowfish_counter; i < BF_BLOCK; i += 4, j++) {
                                tmp[j]  = ((BF_LONG)*p++) << 24;
                                tmp[j] |= ((BF_LONG)*p++) << 16;
                                tmp[j] |= ((BF_LONG)*p++) << 8;
                                tmp[j] |= ((BF_LONG)*p++);
                        }

                        BF_encrypt(tmp, &c->blowfish_ctx);

                        for (i = j = 0, p = buf; i < BF_BLOCK; i += 4, j++) {
                                *p++ = (unsigned char)(tmp[j] >> 24);
                                *p++ = (unsigned char)(tmp[j] >> 16);
                                *p++ = (unsigned char)(tmp[j] >> 8);
                                *p++ = (unsigned char)tmp[j];
                        }

                        ssh_ctr_inc(c->blowfish_counter, BF_BLOCK);
                }
                *(dest++) = *(src++) ^ buf[n];
                n = (n + 1) % BF_BLOCK;
        }
        return (1);
}

static int
ssh_bf_ctr_init(EVP_CIPHER_CTX *ctx, const unsigned char *key, const unsigned char *iv, int enc)
{
        struct ssh_blowfish_ctr_ctx *c;

        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
                c = malloc(sizeof(*c));
                EVP_CIPHER_CTX_set_app_data(ctx, c);
        }
        if (key != NULL) {
                BF_set_key(&c->blowfish_ctx, EVP_CIPHER_CTX_key_length(ctx), key);
        }

        if (iv != NULL)
                memcpy(c->blowfish_counter, iv, BF_BLOCK);
        return (1);
}

static int
ssh_bf_ctr_cleanup(EVP_CIPHER_CTX *ctx)
{
        struct ssh_blowfish_ctr_ctx *c;

        if((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
                memset(c, 0, sizeof(*c));
                free(c);
                EVP_CIPHER_CTX_set_app_data(ctx, NULL);
        }
        return (1);
}

const EVP_CIPHER *
evp_bf_ctr(void)
{
        static EVP_CIPHER blowfish_ctr;

        memset(&blowfish_ctr, 0, sizeof(EVP_CIPHER));
        blowfish_ctr.nid = NID_undef;
        blowfish_ctr.block_size = BF_BLOCK;
        blowfish_ctr.iv_len = BF_BLOCK;
        blowfish_ctr.key_len = 16;
        blowfish_ctr.init = ssh_bf_ctr_init;
        blowfish_ctr.cleanup = ssh_bf_ctr_cleanup;
        blowfish_ctr.do_cipher = ssh_bf_ctr;
#ifndef SSH_OLD_EVP
        blowfish_ctr.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH | EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV;
#endif
        return (&blowfish_ctr);
}

//============================================================================
// CAST-128
//============================================================================
static int
ssh_cast5_ctr(EVP_CIPHER_CTX *ctx, unsigned char *dest, const unsigned char *src, unsigned int len)
{
        struct ssh_cast5_ctr_ctx *c;
        unsigned int n = 0;
        unsigned char buf[CAST_BLOCK];
        int i, j;
        CAST_LONG tmp[(CAST_BLOCK + 3) / 4];
        unsigned char *p;

        if (len == 0)
                return (1);
        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL)
                return (0);

        while ((len--) > 0) {
                if (n == 0) {
                        for (i = j = 0, p = c->cast5_counter; i < CAST_BLOCK; i += 4, j++) {
                                tmp[j]  = ((CAST_LONG)*p++) << 24;
                                tmp[j] |= ((CAST_LONG)*p++) << 16;
                                tmp[j] |= ((CAST_LONG)*p++) << 8;
                                tmp[j] |= ((CAST_LONG)*p++);
                        }

                        CAST_encrypt(tmp, &c->cast5_ctx);

                        for (i = j = 0, p = buf; i < CAST_BLOCK; i += 4, j++) {
                                *p++ = (unsigned char)(tmp[j] >> 24);
                                *p++ = (unsigned char)(tmp[j] >> 16);
                                *p++ = (unsigned char)(tmp[j] >> 8);
                                *p++ = (unsigned char)tmp[j];
                        }

                        ssh_ctr_inc(c->cast5_counter, CAST_BLOCK);
                }
                *(dest++) = *(src++) ^ buf[n];
                n = (n + 1) % CAST_BLOCK;
        }
        return (1);
}

static int
ssh_cast5_ctr_init(EVP_CIPHER_CTX *ctx, const unsigned char *key, const unsigned char *iv, int enc)
{
        struct ssh_cast5_ctr_ctx *c;

        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
                c = malloc(sizeof(*c));
                EVP_CIPHER_CTX_set_app_data(ctx, c);
        }
        if (key != NULL) {
                CAST_set_key(&c->cast5_ctx, EVP_CIPHER_CTX_key_length(ctx), key);
        }

        if (iv != NULL)
                memcpy(c->cast5_counter, iv, CAST_BLOCK);
        return (1);
}

static int
ssh_cast5_ctr_cleanup(EVP_CIPHER_CTX *ctx)
{
        struct ssh_cast5_ctr_ctx *c;

        if((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
                memset(c, 0, sizeof(*c));
                free(c);
                EVP_CIPHER_CTX_set_app_data(ctx, NULL);
        }
        return (1);
}

const EVP_CIPHER *
evp_cast5_ctr(void)
{
        static EVP_CIPHER cast5_ctr;

        memset(&cast5_ctr, 0, sizeof(EVP_CIPHER));
        cast5_ctr.nid = NID_undef;
        cast5_ctr.block_size = CAST_BLOCK;
        cast5_ctr.iv_len = CAST_BLOCK;
        cast5_ctr.key_len = 16;
        cast5_ctr.init = ssh_cast5_ctr_init;
        cast5_ctr.cleanup = ssh_cast5_ctr_cleanup;
        cast5_ctr.do_cipher = ssh_cast5_ctr;
#ifndef SSH_OLD_EVP
        cast5_ctr.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH | EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV;
#endif
        return (&cast5_ctr);
}

//============================================================================
// Camellia
//============================================================================
static int
ssh_camellia_ctr(EVP_CIPHER_CTX *ctx, unsigned char *dest, const unsigned char *src, unsigned int len)
{
        struct ssh_camellia_ctr_ctx *c;
        unsigned int n = 0;
        unsigned char buf[CAMELLIA_BLOCK_SIZE];

        if (len == 0)
                return (1);
        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL)
                return (0);

        while ((len--) > 0) {
                if (n == 0) {
                        Camellia_encrypt(c->camellia_counter, buf, &c->camellia_ctx);
                        ssh_ctr_inc(c->camellia_counter, CAMELLIA_BLOCK_SIZE);
                }
                *(dest++) = *(src++) ^ buf[n];
                n = (n + 1) % CAMELLIA_BLOCK_SIZE;
        }
        return (1);
}

static int
ssh_camellia_ctr_init(EVP_CIPHER_CTX *ctx, const unsigned char *key, const unsigned char *iv, int enc)
{
        struct ssh_camellia_ctr_ctx *c;

        if ((c = EVP_CIPHER_CTX_get_app_data(ctx)) == NULL) {
                c = malloc(sizeof(*c));
                EVP_CIPHER_CTX_set_app_data(ctx, c);
        }
        if (key != NULL)
                Camellia_set_key(key, EVP_CIPHER_CTX_key_length(ctx) * 8, &c->camellia_ctx);
        if (iv != NULL)
                memcpy(c->camellia_counter, iv, CAMELLIA_BLOCK_SIZE);
        return (1);
}

static int
ssh_camellia_ctr_cleanup(EVP_CIPHER_CTX *ctx)
{
        struct ssh_camellia_ctr_ctx *c;

        if((c = EVP_CIPHER_CTX_get_app_data(ctx)) != NULL) {
                memset(c, 0, sizeof(*c));
                free(c);
                EVP_CIPHER_CTX_set_app_data(ctx, NULL);
        }
        return (1);
}

void
ssh_camellia_ctr_iv(EVP_CIPHER_CTX *evp, int doset, unsigned char * iv, unsigned int len)
{
        struct ssh_camellia_ctr_ctx *c;

        if ((c = EVP_CIPHER_CTX_get_app_data(evp)) != NULL)
                if(doset)
                        memcpy(c->camellia_counter, iv, len);
                else
                        memcpy(iv, c->camellia_counter, len);
}

const EVP_CIPHER *
evp_camellia_128_ctr(void)
{
        static EVP_CIPHER camellia_ctr;

        memset(&camellia_ctr, 0, sizeof(EVP_CIPHER));
        camellia_ctr.nid = NID_undef;
        camellia_ctr.block_size = CAMELLIA_BLOCK_SIZE;
        camellia_ctr.iv_len = CAMELLIA_BLOCK_SIZE;
        camellia_ctr.key_len = 16;
        camellia_ctr.init = ssh_camellia_ctr_init;
        camellia_ctr.cleanup = ssh_camellia_ctr_cleanup;
        camellia_ctr.do_cipher = ssh_camellia_ctr;
#ifndef SSH_OLD_EVP
        camellia_ctr.flags = EVP_CIPH_CBC_MODE | EVP_CIPH_VARIABLE_LENGTH | EVP_CIPH_ALWAYS_CALL_INIT | EVP_CIPH_CUSTOM_IV;
#endif
        return (&camellia_ctr);
}