/* crypto/evp/bio_enc.c */

/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)

 * All rights reserved.

 *

 * This package is an SSL implementation written

 * by Eric Young (eay@cryptsoft.com).

 * The implementation was written so as to conform with Netscapes SSL.

 *

 * This library is free for commercial and non-commercial use as long as

 * the following conditions are aheared to.  The following conditions

 * apply to all code found in this distribution, be it the RC4, RSA,

 * lhash, DES, etc., code; not just the SSL code.  The SSL documentation

 * included with this distribution is covered by the same copyright terms

 * except that the holder is Tim Hudson (tjh@cryptsoft.com).

 *

 * Copyright remains Eric Young's, and as such any Copyright notices in

 * the code are not to be removed.

 * If this package is used in a product, Eric Young should be given attribution

 * as the author of the parts of the library used.

 * This can be in the form of a textual message at program startup or

 * in documentation (online or textual) provided with the package.

 *

 * 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 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.

 * 3. All advertising materials mentioning features or use of this software

 *    must display the following acknowledgement:

 *    "This product includes cryptographic software written by

 *     Eric Young (eay@cryptsoft.com)"

 *    The word 'cryptographic' can be left out if the rouines from the library

 *    being used are not cryptographic related :-).

 * 4. If you include any Windows specific code (or a derivative thereof) from

 *    the apps directory (application code) you must include an acknowledgement:

 *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"

 *

 * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``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 OR CONTRIBUTORS 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.

 *

 * The licence and distribution terms for any publically available version or

 * derivative of this code cannot be changed.  i.e. this code cannot simply be

 * copied and put under another distribution licence

 * [including the GNU Public Licence.]

 */

#include <stdio.h>

#include <errno.h>

#include "cryptlib.h"

#include <openssl/buffer.h>

#include <openssl/evp.h>

static int enc_write(BIO *h, const char *buf, int num);

static int enc_read(BIO *h, char *buf, int size);

/*

 * static int enc_puts(BIO *h, const char *str);

 */

/*

 * static int enc_gets(BIO *h, char *str, int size);

 */

static long enc_ctrl(BIO *h, int cmd, long arg1, void *arg2);

static int enc_new(BIO *h);

static int enc_free(BIO *data);

static long enc_callback_ctrl(BIO *h, int cmd, bio_info_cb *fps);

#define ENC_BLOCK_SIZE  (1024*4)

#define BUF_OFFSET      (EVP_MAX_BLOCK_LENGTH*2)

typedef struct enc_struct {

    int buf_len;

    int buf_off;

    int cont;                   /* <= 0 when finished */

    int finished;

    int ok;                     /* bad decrypt */

    EVP_CIPHER_CTX cipher;

    /*

     * buf is larger than ENC_BLOCK_SIZE because EVP_DecryptUpdate can return

     * up to a block more data than is presented to it

     */

    char buf[ENC_BLOCK_SIZE + BUF_OFFSET + 2];

} BIO_ENC_CTX;

static BIO_METHOD methods_enc = {

    BIO_TYPE_CIPHER, "cipher",

    enc_write,

    enc_read,

    NULL,                       /* enc_puts, */

    NULL,                       /* enc_gets, */

    enc_ctrl,

    enc_new,

    enc_free,

    enc_callback_ctrl,

};

BIO_METHOD *BIO_f_cipher(void)

{

    return (&methods_enc);

}

static int enc_new(BIO *bi)

{

    BIO_ENC_CTX *ctx;

    ctx = (BIO_ENC_CTX *)OPENSSL_malloc(sizeof(BIO_ENC_CTX));

    if (ctx == NULL)

        return (0);

    EVP_CIPHER_CTX_init(&ctx->cipher);

    ctx->buf_len = 0;

    ctx->buf_off = 0;

    ctx->cont = 1;

    ctx->finished = 0;

    ctx->ok = 1;

    bi->init = 0;

    bi->ptr = (char *)ctx;

    bi->flags = 0;

    return (1);

}

static int enc_free(BIO *a)

{

    BIO_ENC_CTX *b;

    if (a == NULL)

        return (0);

    b = (BIO_ENC_CTX *)a->ptr;

    EVP_CIPHER_CTX_cleanup(&(b->cipher));

    OPENSSL_cleanse(a->ptr, sizeof(BIO_ENC_CTX));

    OPENSSL_free(a->ptr);

    a->ptr = NULL;

    a->init = 0;

    a->flags = 0;

    return (1);

}

static int enc_read(BIO *b, char *out, int outl)

{

    int ret = 0, i;

    BIO_ENC_CTX *ctx;

    if (out == NULL)

        return (0);

    ctx = (BIO_ENC_CTX *)b->ptr;

    if ((ctx == NULL) || (b->next_bio == NULL))

        return (0);

    /* First check if there are bytes decoded/encoded */

    if (ctx->buf_len > 0) {

        i = ctx->buf_len - ctx->buf_off;

        if (i > outl)

            i = outl;

        memcpy(out, &(ctx->buf[ctx->buf_off]), i);

        ret = i;

        out += i;

        outl -= i;

        ctx->buf_off += i;

        if (ctx->buf_len == ctx->buf_off) {

            ctx->buf_len = 0;

            ctx->buf_off = 0;

        }

    }

    /*

     * At this point, we have room of outl bytes and an empty buffer, so we

     * should read in some more.

     */

    while (outl > 0) {

        if (ctx->cont <= 0)

            break;

        /*

         * read in at IV offset, read the EVP_Cipher documentation about why

         */

        i = BIO_read(b->next_bio, &(ctx->buf[BUF_OFFSET]), ENC_BLOCK_SIZE);

        if (i <= 0) {

            /* Should be continue next time we are called? */

            if (!BIO_should_retry(b->next_bio)) {

                ctx->cont = i;

                i = EVP_CipherFinal_ex(&(ctx->cipher),

                                       (unsigned char *)ctx->buf,

                                       &(ctx->buf_len));

                ctx->ok = i;

                ctx->buf_off = 0;

            } else {

                ret = (ret == 0) ? i : ret;

                break;

            }

        } else {

            if (!EVP_CipherUpdate(&ctx->cipher,

                                  (unsigned char *)ctx->buf, &ctx->buf_len,

                                  (unsigned char *)&(ctx->buf[BUF_OFFSET]),

                                  i)) {

                BIO_clear_retry_flags(b);

                ctx->ok = 0;

                return 0;

            }

            ctx->cont = 1;

            /*

             * Note: it is possible for EVP_CipherUpdate to decrypt zero

             * bytes because this is or looks like the final block: if this

             * happens we should retry and either read more data or decrypt

             * the final block

             */

            if (ctx->buf_len == 0)

                continue;

        }

        if (ctx->buf_len <= outl)

            i = ctx->buf_len;

        else

            i = outl;

        if (i <= 0)

            break;

        memcpy(out, ctx->buf, i);

        ret += i;

        ctx->buf_off = i;

        outl -= i;

        out += i;

    }

    BIO_clear_retry_flags(b);

    BIO_copy_next_retry(b);

    return ((ret == 0) ? ctx->cont : ret);

}

static int enc_write(BIO *b, const char *in, int inl)

{

    int ret = 0, n, i;

    BIO_ENC_CTX *ctx;

    ctx = (BIO_ENC_CTX *)b->ptr;

    ret = inl;

    BIO_clear_retry_flags(b);

    n = ctx->buf_len - ctx->buf_off;

    while (n > 0) {

        i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);

        if (i <= 0) {

            BIO_copy_next_retry(b);

            return (i);

        }

        ctx->buf_off += i;

        n -= i;

    }

    /* at this point all pending data has been written */

    if ((in == NULL) || (inl <= 0))

        return (0);

    ctx->buf_off = 0;

    while (inl > 0) {

        n = (inl > ENC_BLOCK_SIZE) ? ENC_BLOCK_SIZE : inl;

        if (!EVP_CipherUpdate(&ctx->cipher,

                              (unsigned char *)ctx->buf, &ctx->buf_len,

                              (unsigned char *)in, n)) {

            BIO_clear_retry_flags(b);

            ctx->ok = 0;

            return 0;

        }

        inl -= n;

        in += n;

        ctx->buf_off = 0;

        n = ctx->buf_len;

        while (n > 0) {

            i = BIO_write(b->next_bio, &(ctx->buf[ctx->buf_off]), n);

            if (i <= 0) {

                BIO_copy_next_retry(b);

                return (ret == inl) ? i : ret - inl;

            }

            n -= i;

            ctx->buf_off += i;

        }

        ctx->buf_len = 0;

        ctx->buf_off = 0;

    }

    BIO_copy_next_retry(b);

    return (ret);

}

static long enc_ctrl(BIO *b, int cmd, long num, void *ptr)

{

    BIO *dbio;

    BIO_ENC_CTX *ctx, *dctx;

    long ret = 1;

    int i;

    EVP_CIPHER_CTX **c_ctx;

    ctx = (BIO_ENC_CTX *)b->ptr;

    switch (cmd) {

    case BIO_CTRL_RESET:

        ctx->ok = 1;

        ctx->finished = 0;

        EVP_CipherInit_ex(&(ctx->cipher), NULL, NULL, NULL, NULL,

                          ctx->cipher.encrypt);

        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);

        break;

    case BIO_CTRL_EOF:         /* More to read */

        if (ctx->cont <= 0)

            ret = 1;

        else

            ret = BIO_ctrl(b->next_bio, cmd, num, ptr);

        break;

    case BIO_CTRL_WPENDING:

        ret = ctx->buf_len - ctx->buf_off;

        if (ret <= 0)

            ret = BIO_ctrl(b->next_bio, cmd, num, ptr);

        break;

    case BIO_CTRL_PENDING:     /* More to read in buffer */

        ret = ctx->buf_len - ctx->buf_off;

        if (ret <= 0)

            ret = BIO_ctrl(b->next_bio, cmd, num, ptr);

        break;

    case BIO_CTRL_FLUSH:

        /* do a final write */

 again:

        while (ctx->buf_len != ctx->buf_off) {

            i = enc_write(b, NULL, 0);

            if (i < 0)

                return i;

        }

        if (!ctx->finished) {

            ctx->finished = 1;

            ctx->buf_off = 0;

            ret = EVP_CipherFinal_ex(&(ctx->cipher),

                                     (unsigned char *)ctx->buf,

                                     &(ctx->buf_len));

            ctx->ok = (int)ret;

            if (ret <= 0)

                break;

            /* push out the bytes */

            goto again;

        }

        /* Finally flush the underlying BIO */

        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);

        break;

    case BIO_C_GET_CIPHER_STATUS:

        ret = (long)ctx->ok;

        break;

    case BIO_C_DO_STATE_MACHINE:

        BIO_clear_retry_flags(b);

        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);

        BIO_copy_next_retry(b);

        break;

    case BIO_C_GET_CIPHER_CTX:

        c_ctx = (EVP_CIPHER_CTX **)ptr;

        (*c_ctx) = &(ctx->cipher);

        b->init = 1;

        break;

    case BIO_CTRL_DUP:

        dbio = (BIO *)ptr;

        dctx = (BIO_ENC_CTX *)dbio->ptr;

        EVP_CIPHER_CTX_init(&dctx->cipher);

        ret = EVP_CIPHER_CTX_copy(&dctx->cipher, &ctx->cipher);

        if (ret)

            dbio->init = 1;

        break;

    default:

        ret = BIO_ctrl(b->next_bio, cmd, num, ptr);

        break;

    }

    return (ret);

}

static long enc_callback_ctrl(BIO *b, int cmd, bio_info_cb *fp)

{

    long ret = 1;

    if (b->next_bio == NULL)

        return (0);

    switch (cmd) {

    default:

        ret = BIO_callback_ctrl(b->next_bio, cmd, fp);

        break;

    }

    return (ret);

}

/*-

void BIO_set_cipher_ctx(b,c)

BIO *b;

EVP_CIPHER_ctx *c;

        {

        if (b == NULL) return;

        if ((b->callback != NULL) &&

                (b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,0L) <= 0))

                return;

        b->init=1;

        ctx=(BIO_ENC_CTX *)b->ptr;

        memcpy(ctx->cipher,c,sizeof(EVP_CIPHER_CTX));

        if (b->callback != NULL)

                b->callback(b,BIO_CB_CTRL,(char *)c,BIO_CTRL_SET,e,1L);

        }

*/

void BIO_set_cipher(BIO *b, const EVP_CIPHER *c, const unsigned char *k,

                    const unsigned char *i, int e)

{

    BIO_ENC_CTX *ctx;

    if (b == NULL)

        return;

    if ((b->callback != NULL) &&

        (b->callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 0L) <=

         0))

        return;

    b->init = 1;

    ctx = (BIO_ENC_CTX *)b->ptr;

    EVP_CipherInit_ex(&(ctx->cipher), c, NULL, k, i, e);

    if (b->callback != NULL)

        b->callback(b, BIO_CB_CTRL, (const char *)c, BIO_CTRL_SET, e, 1L);

}