/*

 * Copyright 1998-2026 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 <stddef.h>

#include <openssl/x509.h>

#include <openssl/asn1.h>

#include <openssl/asn1t.h>

#include <openssl/err.h>

#include "crypto/asn1.h"

#include "crypto/evp.h"

ASN1_SEQUENCE(X509_ALGOR) = {

    ASN1_SIMPLE(X509_ALGOR, algorithm, ASN1_OBJECT),

    ASN1_OPT(X509_ALGOR, parameter, ASN1_ANY)

} ASN1_SEQUENCE_END(X509_ALGOR)

ASN1_ITEM_TEMPLATE(X509_ALGORS) = ASN1_EX_TEMPLATE_TYPE(ASN1_TFLG_SEQUENCE_OF, 0, algorithms, X509_ALGOR)

ASN1_ITEM_TEMPLATE_END(X509_ALGORS)

IMPLEMENT_ASN1_FUNCTIONS(X509_ALGOR)

IMPLEMENT_ASN1_ENCODE_FUNCTIONS_fname(X509_ALGORS, X509_ALGORS, X509_ALGORS)

IMPLEMENT_ASN1_DUP_FUNCTION(X509_ALGOR)

int X509_ALGOR_set0(X509_ALGOR *alg, ASN1_OBJECT *aobj, int ptype, void *pval)

{

    if (alg == NULL)

        return 0;

    if (ptype != V_ASN1_UNDEF && alg->parameter == NULL

        && (alg->parameter = ASN1_TYPE_new()) == NULL)

        return 0;

    ASN1_OBJECT_free(alg->algorithm);

    alg->algorithm = aobj;

    if (ptype == V_ASN1_EOC)

        return 1;

    if (ptype == V_ASN1_UNDEF) {

        ASN1_TYPE_free(alg->parameter);

        alg->parameter = NULL;

    } else

        ASN1_TYPE_set(alg->parameter, ptype, pval);

    return 1;

}

X509_ALGOR *ossl_X509_ALGOR_from_nid(int nid, int ptype, void *pval)

{

    ASN1_OBJECT *algo = OBJ_nid2obj(nid);

    X509_ALGOR *alg = NULL;

    if (algo == NULL)

        return NULL;

    if ((alg = X509_ALGOR_new()) == NULL)

        goto err;

    if (X509_ALGOR_set0(alg, algo, ptype, pval))

        return alg;

    alg->algorithm = NULL; /* precaution to prevent double free */

err:

    X509_ALGOR_free(alg);

    /* ASN1_OBJECT_free(algo) is not needed due to OBJ_nid2obj() */

    return NULL;

}

void X509_ALGOR_get0(const ASN1_OBJECT **paobj, int *pptype,

    const void **ppval, const X509_ALGOR *algor)

{

    if (paobj)

        *paobj = algor->algorithm;

    if (pptype) {

        if (algor->parameter == NULL) {

            *pptype = V_ASN1_UNDEF;

            return;

        } else

            *pptype = algor->parameter->type;

        if (ppval)

            *ppval = algor->parameter->value.ptr;

    }

}

/* Set up an X509_ALGOR DigestAlgorithmIdentifier from an EVP_MD */

int X509_ALGOR_set_md(X509_ALGOR *alg, const EVP_MD *md)

{

    int type = md->flags & EVP_MD_FLAG_DIGALGID_ABSENT ? V_ASN1_UNDEF

                                                       : V_ASN1_NULL;

    int md_type = EVP_MD_type(md);

    ASN1_OBJECT *obj = (md_type == NID_undef) ? OBJ_txt2obj(EVP_MD_get0_name(md), 0) : OBJ_nid2obj(md_type);

    return X509_ALGOR_set0(alg, obj, type, NULL);

}

int X509_ALGOR_cmp(const X509_ALGOR *a, const X509_ALGOR *b)

{

    int rv;

    rv = OBJ_cmp(a->algorithm, b->algorithm);

    if (rv)

        return rv;

    if (!a->parameter && !b->parameter)

        return 0;

    return ASN1_TYPE_cmp(a->parameter, b->parameter);

}

int X509_ALGOR_copy(X509_ALGOR *dest, const X509_ALGOR *src)

{

    if (src == NULL || dest == NULL)

        return 0;

    if (dest->algorithm)

        ASN1_OBJECT_free(dest->algorithm);

    dest->algorithm = NULL;

    if (dest->parameter)

        ASN1_TYPE_free(dest->parameter);

    dest->parameter = NULL;

    if (src->algorithm)

        if ((dest->algorithm = OBJ_dup(src->algorithm)) == NULL)

            return 0;

    if (src->parameter != NULL) {

        dest->parameter = ASN1_TYPE_new();

        if (dest->parameter == NULL)

            return 0;

        /* Assuming this is also correct for a BOOL.

         * set does copy as a side effect.

         */

        if (ASN1_TYPE_set1(dest->parameter, src->parameter->type,

                src->parameter->value.ptr)

            == 0)

            return 0;

    }

    return 1;

}

/* allocate and set algorithm ID from EVP_MD, default SHA1 */

int ossl_x509_algor_new_from_md(X509_ALGOR **palg, const EVP_MD *md)

{

    X509_ALGOR *alg;

    /* Default is SHA1 so no need to create it - still success */

    if (md == NULL || EVP_MD_is_a(md, "SHA1"))

        return 1;

    if ((alg = X509_ALGOR_new()) == NULL)

        return 0;

    if (!X509_ALGOR_set_md(alg, md)) {

        X509_ALGOR_free(alg);

        return 0;

    }

    *palg = alg;

    return 1;

}

/* convert algorithm ID to EVP_MD, default SHA1 */

const EVP_MD *ossl_x509_algor_get_md(X509_ALGOR *alg)

{

    const EVP_MD *md;

    if (alg == NULL)

        return EVP_sha1();

    md = EVP_get_digestbyobj(alg->algorithm);

    if (md == NULL)

        ERR_raise(ERR_LIB_ASN1, ASN1_R_UNKNOWN_DIGEST);

    return md;

}

X509_ALGOR *ossl_x509_algor_mgf1_decode(X509_ALGOR *alg)

{

    if (OBJ_obj2nid(alg->algorithm) != NID_mgf1)

        return NULL;

    return ASN1_TYPE_unpack_sequence(ASN1_ITEM_rptr(X509_ALGOR),

        alg->parameter);

}

/* Allocate and set MGF1 algorithm ID from EVP_MD */

int ossl_x509_algor_md_to_mgf1(X509_ALGOR **palg, const EVP_MD *mgf1md)

{

    X509_ALGOR *algtmp = NULL;

    ASN1_STRING *stmp = NULL;

    *palg = NULL;

    if (mgf1md == NULL || EVP_MD_is_a(mgf1md, "SHA1"))

        return 1;

    /* need to embed algorithm ID inside another */

    if (!ossl_x509_algor_new_from_md(&algtmp, mgf1md))

        goto err;

    if (ASN1_item_pack(algtmp, ASN1_ITEM_rptr(X509_ALGOR), &stmp) == NULL)

        goto err;

    *palg = ossl_X509_ALGOR_from_nid(NID_mgf1, V_ASN1_SEQUENCE, stmp);

    if (*palg == NULL)

        goto err;

    stmp = NULL;

err:

    ASN1_STRING_free(stmp);

    X509_ALGOR_free(algtmp);

    return *palg != NULL;

}