/*

 * Copyright 2008-2023 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 <openssl/asn1.h>

#include <openssl/asn1t.h>

#include <openssl/bio.h>

#include <openssl/err.h>

#include <stdio.h>

/* Experimental NDEF ASN1 BIO support routines */

/*

 * The usage is quite simple, initialize an ASN1 structure, get a BIO from it

 * then any data written through the BIO will end up translated to

 * appropriate format on the fly. The data is streamed out and does *not*

 * need to be all held in memory at once. When the BIO is flushed the output

 * is finalized and any signatures etc written out. The BIO is a 'proper'

 * BIO and can handle non blocking I/O correctly. The usage is simple. The

 * implementation is *not*...

 */

/* BIO support data stored in the ASN1 BIO ex_arg */

typedef struct ndef_aux_st {

    /* ASN1 structure this BIO refers to */

    ASN1_VALUE *val;

    const ASN1_ITEM *it;

    /* Top of the BIO chain */

    BIO *ndef_bio;

    /* Output BIO */

    BIO *out;

    /* Boundary where content is inserted */

    unsigned char **boundary;

    /* DER buffer start */

    unsigned char *derbuf;

} NDEF_SUPPORT;

static int ndef_prefix(BIO *b, unsigned char **pbuf, int *plen, void *parg);

static int ndef_prefix_free(BIO *b, unsigned char **pbuf, int *plen,

                            void *parg);

static int ndef_suffix(BIO *b, unsigned char **pbuf, int *plen, void *parg);

static int ndef_suffix_free(BIO *b, unsigned char **pbuf, int *plen,

                            void *parg);

/*

 * On success, the returned BIO owns the input BIO as part of its BIO chain.

 * On failure, NULL is returned and the input BIO is owned by the caller.

 *

 * Unfortunately cannot constify this due to CMS_stream() and PKCS7_stream()

 */

BIO *BIO_new_NDEF(BIO *out, ASN1_VALUE *val, const ASN1_ITEM *it)

{

    NDEF_SUPPORT *ndef_aux = NULL;

    BIO *asn_bio = NULL;

    const ASN1_AUX *aux = it->funcs;

    ASN1_STREAM_ARG sarg;

    BIO *pop_bio = NULL;

    if (!aux || !aux->asn1_cb) {

        ERR_raise(ERR_LIB_ASN1, ASN1_R_STREAMING_NOT_SUPPORTED);

        return NULL;

    }

    ndef_aux = OPENSSL_zalloc(sizeof(*ndef_aux));

    asn_bio = BIO_new(BIO_f_asn1());

    if (ndef_aux == NULL || asn_bio == NULL)

        goto err;

    /* ASN1 bio needs to be next to output BIO */

    out = BIO_push(asn_bio, out);

    if (out == NULL)

        goto err;

    pop_bio = asn_bio;

    if (BIO_asn1_set_prefix(asn_bio, ndef_prefix, ndef_prefix_free) <= 0

            || BIO_asn1_set_suffix(asn_bio, ndef_suffix, ndef_suffix_free) <= 0

            || BIO_ctrl(asn_bio, BIO_C_SET_EX_ARG, 0, ndef_aux) <= 0)

        goto err;

    /*

     * Now let the callback prepend any digest, cipher, etc., that the BIO's

     * ASN1 structure needs.

     */

    sarg.out = out;

    sarg.ndef_bio = NULL;

    sarg.boundary = NULL;

    /*

     * The asn1_cb(), must not have mutated asn_bio on error, leaving it in the

     * middle of some partially built, but not returned BIO chain.

     */

    if (aux->asn1_cb(ASN1_OP_STREAM_PRE, &val, it, &sarg) <= 0) {

        /*

         * ndef_aux is now owned by asn_bio so we must not free it in the err

         * clean up block

         */

        ndef_aux = NULL;

        goto err;

    }

    /*

     * We must not fail now because the callback has prepended additional

     * BIOs to the chain

     */

    ndef_aux->val = val;

    ndef_aux->it = it;

    ndef_aux->ndef_bio = sarg.ndef_bio;

    ndef_aux->boundary = sarg.boundary;

    ndef_aux->out = out;

    return sarg.ndef_bio;

 err:

    /* BIO_pop() is NULL safe */

    (void)BIO_pop(pop_bio);

    BIO_free(asn_bio);

    OPENSSL_free(ndef_aux);

    return NULL;

}

static int ndef_prefix(BIO *b, unsigned char **pbuf, int *plen, void *parg)

{

    NDEF_SUPPORT *ndef_aux;

    unsigned char *p;

    int derlen;

    if (parg == NULL)

        return 0;

    ndef_aux = *(NDEF_SUPPORT **)parg;

    derlen = ASN1_item_ndef_i2d(ndef_aux->val, NULL, ndef_aux->it);

    if (derlen < 0)

        return 0;

    if ((p = OPENSSL_malloc(derlen)) == NULL)

        return 0;

    ndef_aux->derbuf = p;

    *pbuf = p;

    ASN1_item_ndef_i2d(ndef_aux->val, &p, ndef_aux->it);

    if (*ndef_aux->boundary == NULL)

        return 0;

    *plen = *ndef_aux->boundary - *pbuf;

    return 1;

}

static int ndef_prefix_free(BIO *b, unsigned char **pbuf, int *plen,

                            void *parg)

{

    NDEF_SUPPORT *ndef_aux;

    if (parg == NULL)

        return 0;

    ndef_aux = *(NDEF_SUPPORT **)parg;

    if (ndef_aux == NULL)

        return 0;

    OPENSSL_free(ndef_aux->derbuf);

    ndef_aux->derbuf = NULL;

    *pbuf = NULL;

    *plen = 0;

    return 1;

}

static int ndef_suffix_free(BIO *b, unsigned char **pbuf, int *plen,

                            void *parg)

{

    NDEF_SUPPORT **pndef_aux = (NDEF_SUPPORT **)parg;

    if (!ndef_prefix_free(b, pbuf, plen, parg))

        return 0;

    OPENSSL_free(*pndef_aux);

    *pndef_aux = NULL;

    return 1;

}

static int ndef_suffix(BIO *b, unsigned char **pbuf, int *plen, void *parg)

{

    NDEF_SUPPORT *ndef_aux;

    unsigned char *p;

    int derlen;

    const ASN1_AUX *aux;

    ASN1_STREAM_ARG sarg;

    if (parg == NULL)

        return 0;

    ndef_aux = *(NDEF_SUPPORT **)parg;

    aux = ndef_aux->it->funcs;

    /* Finalize structures */

    sarg.ndef_bio = ndef_aux->ndef_bio;

    sarg.out = ndef_aux->out;

    sarg.boundary = ndef_aux->boundary;

    if (aux->asn1_cb(ASN1_OP_STREAM_POST,

                     &ndef_aux->val, ndef_aux->it, &sarg) <= 0)

        return 0;

    derlen = ASN1_item_ndef_i2d(ndef_aux->val, NULL, ndef_aux->it);

    if (derlen < 0)

        return 0;

    if ((p = OPENSSL_malloc(derlen)) == NULL)

        return 0;

    ndef_aux->derbuf = p;

    *pbuf = p;

    derlen = ASN1_item_ndef_i2d(ndef_aux->val, &p, ndef_aux->it);

    if (*ndef_aux->boundary == NULL)

        return 0;

    *pbuf = *ndef_aux->boundary;

    *plen = derlen - (*ndef_aux->boundary - ndef_aux->derbuf);

    return 1;

}