/*

 * Copyright 1995-2021 The OpenSSL Project Authors. All Rights Reserved.

 *

 * Licensed under the Apache License 2.0 (the "License").  You may not use

 * this file except in compliance with the License.  You can obtain a copy

 * in the file LICENSE in the source distribution or at

 * https://www.openssl.org/source/license.html

 */

#include <stdio.h>

#include <errno.h>

#include <openssl/buffer.h>

#include <openssl/evp.h>

#include "internal/bio.h"

/*

 * BIO_put and BIO_get both add to the digest, BIO_gets returns the digest

 */

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

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

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

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

static int md_new(BIO *h);

static int md_free(BIO *data);

static long md_callback_ctrl(BIO *h, int cmd, BIO_info_cb *fp);

static const BIO_METHOD methods_md = {

    BIO_TYPE_MD,

    "message digest",

    bwrite_conv,

    md_write,

    bread_conv,

    md_read,

    NULL, /* md_puts, */

    md_gets,

    md_ctrl,

    md_new,

    md_free,

    md_callback_ctrl,

};

const BIO_METHOD *BIO_f_md(void)

{

    return &methods_md;

}

static int md_new(BIO *bi)

{

    EVP_MD_CTX *ctx;

    ctx = EVP_MD_CTX_new();

    if (ctx == NULL)

        return 0;

    BIO_set_init(bi, 1);

    BIO_set_data(bi, ctx);

    return 1;

}

static int md_free(BIO *a)

{

    if (a == NULL)

        return 0;

    EVP_MD_CTX_free(BIO_get_data(a));

    BIO_set_data(a, NULL);

    BIO_set_init(a, 0);

    return 1;

}

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

{

    int ret = 0;

    EVP_MD_CTX *ctx;

    BIO *next;

    if (out == NULL)

        return 0;

    ctx = BIO_get_data(b);

    next = BIO_next(b);

    if ((ctx == NULL) || (next == NULL))

        return 0;

    ret = BIO_read(next, out, outl);

    if (BIO_get_init(b)) {

        if (ret > 0) {

            if (EVP_DigestUpdate(ctx, (unsigned char *)out,

                    (unsigned int)ret)

                <= 0)

                return -1;

        }

    }

    BIO_clear_retry_flags(b);

    BIO_copy_next_retry(b);

    return ret;

}

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

{

    int ret = 0;

    EVP_MD_CTX *ctx;

    BIO *next;

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

        return 0;

    ctx = BIO_get_data(b);

    next = BIO_next(b);

    if ((ctx != NULL) && (next != NULL))

        ret = BIO_write(next, in, inl);

    if (BIO_get_init(b)) {

        if (ret > 0) {

            if (!EVP_DigestUpdate(ctx, (const unsigned char *)in,

                    (unsigned int)ret)) {

                BIO_clear_retry_flags(b);

                return 0;

            }

        }

    }

    if (next != NULL) {

        BIO_clear_retry_flags(b);

        BIO_copy_next_retry(b);

    }

    return ret;

}

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

{

    EVP_MD_CTX *ctx, *dctx, **pctx;

    const EVP_MD **ppmd;

    EVP_MD *md;

    long ret = 1;

    BIO *dbio, *next;

    ctx = BIO_get_data(b);

    next = BIO_next(b);

    switch (cmd) {

    case BIO_CTRL_RESET:

        if (BIO_get_init(b))

            ret = EVP_DigestInit_ex(ctx, EVP_MD_CTX_get0_md(ctx), NULL);

        else

            ret = 0;

        if (ret > 0)

            ret = BIO_ctrl(next, cmd, num, ptr);

        break;

    case BIO_C_GET_MD:

        if (BIO_get_init(b)) {

            ppmd = ptr;

            *ppmd = EVP_MD_CTX_get0_md(ctx);

        } else

            ret = 0;

        break;

    case BIO_C_GET_MD_CTX:

        pctx = ptr;

        *pctx = ctx;

        BIO_set_init(b, 1);

        break;

    case BIO_C_SET_MD_CTX:

        if (BIO_get_init(b))

            BIO_set_data(b, ptr);

        else

            ret = 0;

        break;

    case BIO_C_DO_STATE_MACHINE:

        BIO_clear_retry_flags(b);

        ret = BIO_ctrl(next, cmd, num, ptr);

        BIO_copy_next_retry(b);

        break;

    case BIO_C_SET_MD:

        md = ptr;

        ret = EVP_DigestInit_ex(ctx, md, NULL);

        if (ret > 0)

            BIO_set_init(b, 1);

        break;

    case BIO_CTRL_DUP:

        dbio = ptr;

        dctx = BIO_get_data(dbio);

        if (!EVP_MD_CTX_copy_ex(dctx, ctx))

            return 0;

        BIO_set_init(b, 1);

        break;

    default:

        ret = BIO_ctrl(next, cmd, num, ptr);

        break;

    }

    return ret;

}

static long md_callback_ctrl(BIO *b, int cmd, BIO_info_cb *fp)

{

    BIO *next;

    next = BIO_next(b);

    if (next == NULL)

        return 0;

    return BIO_callback_ctrl(next, cmd, fp);

}

static int md_gets(BIO *bp, char *buf, int size)

{

    EVP_MD_CTX *ctx;

    unsigned int ret;

    ctx = BIO_get_data(bp);

    if (size < EVP_MD_CTX_get_size(ctx))

        return 0;

    if (EVP_DigestFinal_ex(ctx, (unsigned char *)buf, &ret) <= 0)

        return -1;

    return (int)ret;

}