/*

 * Copyright 2019-2024 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 <string.h>

#include <openssl/x509v3.h>

#include <openssl/err.h>

#include <openssl/ess.h>

#include "internal/sizes.h"

#include "crypto/ess.h"

#include "crypto/x509.h"

static ESS_CERT_ID *ESS_CERT_ID_new_init(const X509 *cert,

    int set_issuer_serial);

static ESS_CERT_ID_V2 *ESS_CERT_ID_V2_new_init(const EVP_MD *hash_alg,

    const X509 *cert,

    int set_issuer_serial);

ESS_SIGNING_CERT *OSSL_ESS_signing_cert_new_init(const X509 *signcert,

    const STACK_OF(X509) *certs,

    int set_issuer_serial)

{

    ESS_CERT_ID *cid = NULL;

    ESS_SIGNING_CERT *sc;

    int i;

    if ((sc = ESS_SIGNING_CERT_new()) == NULL)

        goto err;

    if (sc->cert_ids == NULL

        && (sc->cert_ids = sk_ESS_CERT_ID_new_null()) == NULL)

        goto err;

    if ((cid = ESS_CERT_ID_new_init(signcert, set_issuer_serial)) == NULL

        || !sk_ESS_CERT_ID_push(sc->cert_ids, cid))

        goto err;

    for (i = 0; i < sk_X509_num(certs); ++i) {

        X509 *cert = sk_X509_value(certs, i);

        if ((cid = ESS_CERT_ID_new_init(cert, 1)) == NULL

            || !sk_ESS_CERT_ID_push(sc->cert_ids, cid))

            goto err;

    }

    return sc;

err:

    ESS_SIGNING_CERT_free(sc);

    ESS_CERT_ID_free(cid);

    ERR_raise(ERR_LIB_ESS, ERR_R_MALLOC_FAILURE);

    return NULL;

}

static ESS_CERT_ID *ESS_CERT_ID_new_init(const X509 *cert,

    int set_issuer_serial)

{

    ESS_CERT_ID *cid = NULL;

    GENERAL_NAME *name = NULL;

    unsigned char cert_sha1[SHA_DIGEST_LENGTH];

    if ((cid = ESS_CERT_ID_new()) == NULL)

        goto err;

    if (!X509_digest(cert, EVP_sha1(), cert_sha1, NULL))

        goto err;

    if (!ASN1_OCTET_STRING_set(cid->hash, cert_sha1, SHA_DIGEST_LENGTH))

        goto err;

    /* Setting the issuer/serial if requested. */

    if (!set_issuer_serial)

        return cid;

    if (cid->issuer_serial == NULL

        && (cid->issuer_serial = ESS_ISSUER_SERIAL_new()) == NULL)

        goto err;

    if ((name = GENERAL_NAME_new()) == NULL)

        goto err;

    name->type = GEN_DIRNAME;

    if ((name->d.dirn = X509_NAME_dup(X509_get_issuer_name(cert))) == NULL)

        goto err;

    if (!sk_GENERAL_NAME_push(cid->issuer_serial->issuer, name))

        goto err;

    name = NULL; /* Ownership is lost. */

    ASN1_INTEGER_free(cid->issuer_serial->serial);

    if ((cid->issuer_serial->serial = ASN1_INTEGER_dup(X509_get0_serialNumber(cert))) == NULL)

        goto err;

    return cid;

err:

    GENERAL_NAME_free(name);

    ESS_CERT_ID_free(cid);

    ERR_raise(ERR_LIB_ESS, ERR_R_MALLOC_FAILURE);

    return NULL;

}

ESS_SIGNING_CERT_V2 *OSSL_ESS_signing_cert_v2_new_init(const EVP_MD *hash_alg,

    const X509 *signcert,

    const STACK_OF(X509) *certs,

    int set_issuer_serial)

{

    ESS_CERT_ID_V2 *cid = NULL;

    ESS_SIGNING_CERT_V2 *sc;

    int i;

    if ((sc = ESS_SIGNING_CERT_V2_new()) == NULL)

        goto err;

    cid = ESS_CERT_ID_V2_new_init(hash_alg, signcert, set_issuer_serial);

    if (cid == NULL)

        goto err;

    if (!sk_ESS_CERT_ID_V2_push(sc->cert_ids, cid))

        goto err;

    cid = NULL;

    for (i = 0; i < sk_X509_num(certs); ++i) {

        X509 *cert = sk_X509_value(certs, i);

        if ((cid = ESS_CERT_ID_V2_new_init(hash_alg, cert, 1)) == NULL)

            goto err;

        if (!sk_ESS_CERT_ID_V2_push(sc->cert_ids, cid))

            goto err;

        cid = NULL;

    }

    return sc;

err:

    ESS_SIGNING_CERT_V2_free(sc);

    ESS_CERT_ID_V2_free(cid);

    ERR_raise(ERR_LIB_ESS, ERR_R_MALLOC_FAILURE);

    return NULL;

}

static ESS_CERT_ID_V2 *ESS_CERT_ID_V2_new_init(const EVP_MD *hash_alg,

    const X509 *cert,

    int set_issuer_serial)

{

    ESS_CERT_ID_V2 *cid;

    GENERAL_NAME *name = NULL;

    unsigned char hash[EVP_MAX_MD_SIZE];

    unsigned int hash_len = sizeof(hash);

    X509_ALGOR *alg = NULL;

    memset(hash, 0, sizeof(hash));

    if ((cid = ESS_CERT_ID_V2_new()) == NULL)

        goto err;

    if (!EVP_MD_is_a(hash_alg, SN_sha256)) {

        alg = X509_ALGOR_new();

        if (alg == NULL)

            goto err;

        X509_ALGOR_set_md(alg, hash_alg);

        if (alg->algorithm == NULL)

            goto err;

        cid->hash_alg = alg;

        alg = NULL;

    } else {

        cid->hash_alg = NULL;

    }

    if (!X509_digest(cert, hash_alg, hash, &hash_len))

        goto err;

    if (!ASN1_OCTET_STRING_set(cid->hash, hash, hash_len))

        goto err;

    if (!set_issuer_serial)

        return cid;

    if ((cid->issuer_serial = ESS_ISSUER_SERIAL_new()) == NULL)

        goto err;

    if ((name = GENERAL_NAME_new()) == NULL)

        goto err;

    name->type = GEN_DIRNAME;

    if ((name->d.dirn = X509_NAME_dup(X509_get_issuer_name(cert))) == NULL)

        goto err;

    if (!sk_GENERAL_NAME_push(cid->issuer_serial->issuer, name))

        goto err;

    name = NULL; /* Ownership is lost. */

    ASN1_INTEGER_free(cid->issuer_serial->serial);

    cid->issuer_serial->serial = ASN1_INTEGER_dup(X509_get0_serialNumber(cert));

    if (cid->issuer_serial->serial == NULL)

        goto err;

    return cid;

err:

    X509_ALGOR_free(alg);

    GENERAL_NAME_free(name);

    ESS_CERT_ID_V2_free(cid);

    ERR_raise(ERR_LIB_ESS, ERR_R_MALLOC_FAILURE);

    return NULL;

}

static int ess_issuer_serial_cmp(const ESS_ISSUER_SERIAL *is, const X509 *cert)

{

    GENERAL_NAME *issuer;

    if (is == NULL || cert == NULL || sk_GENERAL_NAME_num(is->issuer) != 1)

        return -1;

    issuer = sk_GENERAL_NAME_value(is->issuer, 0);

    if (issuer->type != GEN_DIRNAME

        || X509_NAME_cmp(issuer->d.dirn, X509_get_issuer_name(cert)) != 0)

        return -1;

    return ASN1_INTEGER_cmp(is->serial, X509_get0_serialNumber(cert));

}

/*

 * Find the cert in |certs| referenced by |cid| if not NULL, else by |cid_v2|.

 * The cert must be the first one in |certs| if and only if |index| is 0.

 * Return 0 on not found, -1 on error, else 1 + the position in |certs|.

 */

static int find(const ESS_CERT_ID *cid, const ESS_CERT_ID_V2 *cid_v2,

    int index, const STACK_OF(X509) *certs)

{

    const X509 *cert;

    EVP_MD *md = NULL;

    char name[OSSL_MAX_NAME_SIZE];

    unsigned char cert_digest[EVP_MAX_MD_SIZE];

    unsigned int len, cid_hash_len;

    const ESS_ISSUER_SERIAL *is;

    int i;

    int ret = -1;

    if (cid == NULL && cid_v2 == NULL) {

        ERR_raise(ERR_LIB_ESS, ERR_R_PASSED_INVALID_ARGUMENT);

        return -1;

    }

    if (cid != NULL)

        strcpy(name, "SHA1");

    else if (cid_v2->hash_alg == NULL)

        strcpy(name, "SHA256");

    else

        OBJ_obj2txt(name, sizeof(name), cid_v2->hash_alg->algorithm, 0);

    (void)ERR_set_mark();

    md = EVP_MD_fetch(NULL, name, NULL);

    if (md == NULL)

        md = (EVP_MD *)EVP_get_digestbyname(name);

    if (md == NULL) {

        (void)ERR_clear_last_mark();

        ERR_raise(ERR_LIB_ESS, ESS_R_ESS_DIGEST_ALG_UNKNOWN);

        goto end;

    }

    (void)ERR_pop_to_mark();

    for (i = 0; i < sk_X509_num(certs); ++i) {

        cert = sk_X509_value(certs, i);

        cid_hash_len = cid != NULL ? cid->hash->length : cid_v2->hash->length;

        if (!X509_digest(cert, md, cert_digest, &len)

            || cid_hash_len != len) {

            ERR_raise(ERR_LIB_ESS, ESS_R_ESS_CERT_DIGEST_ERROR);

            goto end;

        }

        if (memcmp(cid != NULL ? cid->hash->data : cid_v2->hash->data,

                cert_digest, len)

            == 0) {

            is = cid != NULL ? cid->issuer_serial : cid_v2->issuer_serial;

            /* Well, it's not really required to match the serial numbers. */

            if (is == NULL || ess_issuer_serial_cmp(is, cert) == 0) {

                if ((i == 0) == (index == 0)) {

                    ret = i + 1;

                    goto end;

                }

                ERR_raise(ERR_LIB_ESS, ESS_R_ESS_CERT_ID_WRONG_ORDER);

                goto end;

            }

        }

    }

    ret = 0;

    ERR_raise(ERR_LIB_ESS, ESS_R_ESS_CERT_ID_NOT_FOUND);

end:

    EVP_MD_free(md);

    return ret;

}

int OSSL_ESS_check_signing_certs(const ESS_SIGNING_CERT *ss,

    const ESS_SIGNING_CERT_V2 *ssv2,

    const STACK_OF(X509) *chain,

    int require_signing_cert)

{

    int n_v1 = ss == NULL ? -1 : sk_ESS_CERT_ID_num(ss->cert_ids);

    int n_v2 = ssv2 == NULL ? -1 : sk_ESS_CERT_ID_V2_num(ssv2->cert_ids);

    int i, ret;

    if (require_signing_cert && ss == NULL && ssv2 == NULL) {

        ERR_raise(ERR_LIB_ESS, ESS_R_MISSING_SIGNING_CERTIFICATE_ATTRIBUTE);

        return -1;

    }

    if (n_v1 == 0 || n_v2 == 0) {

        ERR_raise(ERR_LIB_ESS, ESS_R_EMPTY_ESS_CERT_ID_LIST);

        return -1;

    }

    /* If both ss and ssv2 exist, as required evaluate them independently. */

    for (i = 0; i < n_v1; i++) {

        ret = find(sk_ESS_CERT_ID_value(ss->cert_ids, i), NULL, i, chain);

        if (ret <= 0)

            return ret;

    }

    for (i = 0; i < n_v2; i++) {

        ret = find(NULL, sk_ESS_CERT_ID_V2_value(ssv2->cert_ids, i), i, chain);

        if (ret <= 0)

            return ret;

    }

    return 1;

}