/*

 * Copyright 1999-2021 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 "internal/cryptlib.h"

#include <openssl/conf.h>

#include <openssl/asn1.h>

#include <openssl/asn1t.h>

#include <openssl/x509v3.h>

#include "crypto/x509.h"

#include "ext_dat.h"

static STACK_OF(CONF_VALUE) *i2v_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,

                                                 AUTHORITY_KEYID *akeyid,

                                                 STACK_OF(CONF_VALUE)

                                                 *extlist);

static AUTHORITY_KEYID *v2i_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,

                                            X509V3_CTX *ctx,

                                            STACK_OF(CONF_VALUE) *values);

const X509V3_EXT_METHOD ossl_v3_akey_id = {

    NID_authority_key_identifier,

    X509V3_EXT_MULTILINE, ASN1_ITEM_ref(AUTHORITY_KEYID),

    0, 0, 0, 0,

    0, 0,

    (X509V3_EXT_I2V) i2v_AUTHORITY_KEYID,

    (X509V3_EXT_V2I)v2i_AUTHORITY_KEYID,

    0, 0,

    NULL

};

static STACK_OF(CONF_VALUE) *i2v_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,

                                                 AUTHORITY_KEYID *akeyid,

                                                 STACK_OF(CONF_VALUE)

                                                 *extlist)

{

    char *tmp = NULL;

    STACK_OF(CONF_VALUE) *origextlist = extlist, *tmpextlist;

    if (akeyid->keyid) {

        tmp = OPENSSL_buf2hexstr(akeyid->keyid->data, akeyid->keyid->length);

        if (tmp == NULL) {

            ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);

            return NULL;

        }

        if (!X509V3_add_value((akeyid->issuer || akeyid->serial) ? "keyid" : NULL,

                              tmp, &extlist)) {

            OPENSSL_free(tmp);

            ERR_raise(ERR_LIB_X509V3, ERR_R_X509_LIB);

            goto err;

        }

        OPENSSL_free(tmp);

    }

    if (akeyid->issuer) {

        tmpextlist = i2v_GENERAL_NAMES(NULL, akeyid->issuer, extlist);

        if (tmpextlist == NULL) {

            ERR_raise(ERR_LIB_X509V3, ERR_R_X509_LIB);

            goto err;

        }

        extlist = tmpextlist;

    }

    if (akeyid->serial) {

        tmp = OPENSSL_buf2hexstr(akeyid->serial->data, akeyid->serial->length);

        if (tmp == NULL) {

            ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);

            goto err;

        }

        if (!X509V3_add_value("serial", tmp, &extlist)) {

            OPENSSL_free(tmp);

            goto err;

        }

        OPENSSL_free(tmp);

    }

    return extlist;

 err:

    if (origextlist == NULL)

        sk_CONF_VALUE_pop_free(extlist, X509V3_conf_free);

    return NULL;

}

/*-

 * Currently two options:

 * keyid: use the issuers subject keyid, the value 'always' means its is

 * an error if the issuer certificate doesn't have a key id.

 * issuer: use the issuers cert issuer and serial number. The default is

 * to only use this if keyid is not present. With the option 'always'

 * this is always included.

 */

static AUTHORITY_KEYID *v2i_AUTHORITY_KEYID(X509V3_EXT_METHOD *method,

                                            X509V3_CTX *ctx,

                                            STACK_OF(CONF_VALUE) *values)

{

    char keyid = 0, issuer = 0;

    int i, n = sk_CONF_VALUE_num(values);

    CONF_VALUE *cnf;

    ASN1_OCTET_STRING *ikeyid = NULL;

    X509_NAME *isname = NULL;

    GENERAL_NAMES *gens = NULL;

    GENERAL_NAME *gen = NULL;

    ASN1_INTEGER *serial = NULL;

    X509_EXTENSION *ext;

    X509 *issuer_cert;

    int same_issuer, ss;

    AUTHORITY_KEYID *akeyid = AUTHORITY_KEYID_new();

    if (akeyid == NULL)

        goto err;

    if (n == 1 && strcmp(sk_CONF_VALUE_value(values, 0)->name, "none") == 0) {

        return akeyid;

    }

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

        cnf = sk_CONF_VALUE_value(values, i);

        if (strcmp(cnf->name, "keyid") == 0) {

            keyid = 1;

            if (cnf->value && strcmp(cnf->value, "always") == 0)

                keyid = 2;

        } else if (strcmp(cnf->name, "issuer") == 0) {

            issuer = 1;

            if (cnf->value && strcmp(cnf->value, "always") == 0)

                issuer = 2;

        } else {

            ERR_raise_data(ERR_LIB_X509V3, X509V3_R_UNKNOWN_OPTION,

                           "name=%s", cnf->name);

            goto err;

        }

    }

    if (ctx != NULL && (ctx->flags & X509V3_CTX_TEST) != 0)

        return akeyid;

    if (ctx == NULL) {

        ERR_raise(ERR_LIB_X509V3, ERR_R_PASSED_NULL_PARAMETER);

        goto err;

    }

    if ((issuer_cert = ctx->issuer_cert) == NULL) {

        ERR_raise(ERR_LIB_X509V3, X509V3_R_NO_ISSUER_CERTIFICATE);

        goto err;

    }

    same_issuer = ctx->subject_cert == ctx->issuer_cert;

    ERR_set_mark();

    if (ctx->issuer_pkey != NULL)

        ss = X509_check_private_key(ctx->subject_cert, ctx->issuer_pkey);

    else

        ss = same_issuer;

    ERR_pop_to_mark();

    /* unless forced with "always", AKID is suppressed for self-signed certs */

    if (keyid == 2 || (keyid == 1 && !ss)) {

        /*

         * prefer any pre-existing subject key identifier of the issuer cert

         * except issuer cert is same as subject cert and is not self-signed

         */

        i = X509_get_ext_by_NID(issuer_cert, NID_subject_key_identifier, -1);

        if (i >= 0 && (ext = X509_get_ext(issuer_cert, i)) != NULL

            && !(same_issuer && !ss))

            ikeyid = X509V3_EXT_d2i(ext);

        if (ikeyid == NULL && same_issuer && ctx->issuer_pkey != NULL) {

            /* generate fallback AKID, emulating s2i_skey_id(..., "hash") */

            X509_PUBKEY *pubkey = NULL;

            if (X509_PUBKEY_set(&pubkey, ctx->issuer_pkey))

                ikeyid = ossl_x509_pubkey_hash(pubkey);

            X509_PUBKEY_free(pubkey);

        }

        if ((keyid == 2 || issuer == 0)

            && (ikeyid == NULL

                || ASN1_STRING_length(ikeyid) <= 2) /* indicating "none" */) {

            ERR_raise(ERR_LIB_X509V3, X509V3_R_UNABLE_TO_GET_ISSUER_KEYID);

            goto err;

        }

    }

    if (issuer == 2 || (issuer == 1 && ikeyid == NULL)) {

        isname = X509_NAME_dup(X509_get_issuer_name(issuer_cert));

        serial = ASN1_INTEGER_dup(X509_get0_serialNumber(issuer_cert));

        if (isname == NULL || serial == NULL) {

            ERR_raise(ERR_LIB_X509V3, X509V3_R_UNABLE_TO_GET_ISSUER_DETAILS);

            goto err;

        }

    }

    if (isname != NULL) {

        if ((gens = sk_GENERAL_NAME_new_null()) == NULL

            || (gen = GENERAL_NAME_new()) == NULL

            || !sk_GENERAL_NAME_push(gens, gen)) {

            ERR_raise(ERR_LIB_X509V3, ERR_R_MALLOC_FAILURE);

            goto err;

        }

        gen->type = GEN_DIRNAME;

        gen->d.dirn = isname;

    }

    akeyid->issuer = gens;

    gen = NULL;

    gens = NULL;

    akeyid->serial = serial;

    akeyid->keyid = ikeyid;

    return akeyid;

 err:

    sk_GENERAL_NAME_free(gens);

    GENERAL_NAME_free(gen);

    X509_NAME_free(isname);

    ASN1_INTEGER_free(serial);

    ASN1_OCTET_STRING_free(ikeyid);

    AUTHORITY_KEYID_free(akeyid);

    return NULL;

}