/*
 * Copyright 1999-2021 The OpenSSL Project Authors. All Rights Reserved.
 *
 * Licensed under the OpenSSL license (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 "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 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) {
            X509V3err(X509V3_F_I2V_AUTHORITY_KEYID, ERR_R_MALLOC_FAILURE);
            return NULL;
        }
        if (!X509V3_add_value("keyid", tmp, &extlist)) {
            OPENSSL_free(tmp);
            X509V3err(X509V3_F_I2V_AUTHORITY_KEYID, ERR_R_X509_LIB);
            goto err;
        }
        OPENSSL_free(tmp);
    }
    if (akeyid->issuer) {
        tmpextlist = i2v_GENERAL_NAMES(NULL, akeyid->issuer, extlist);
        if (tmpextlist == NULL) {
            X509V3err(X509V3_F_I2V_AUTHORITY_KEYID, ERR_R_X509_LIB);
            goto err;
        }
        extlist = tmpextlist;
    }
    if (akeyid->serial) {
        tmp = OPENSSL_buf2hexstr(akeyid->serial->data, akeyid->serial->length);
        if (tmp == NULL) {
            X509V3err(X509V3_F_I2V_AUTHORITY_KEYID, ERR_R_MALLOC_FAILURE);
            goto err;
        }
        if (!X509V3_add_value("serial", tmp, &extlist)) {
            OPENSSL_free(tmp);
            X509V3err(X509V3_F_I2V_AUTHORITY_KEYID, ERR_R_X509_LIB);
            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;
    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 *cert;
    AUTHORITY_KEYID *akeyid;

    for (i = 0; i < sk_CONF_VALUE_num(values); 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 {
            X509V3err(X509V3_F_V2I_AUTHORITY_KEYID, X509V3_R_UNKNOWN_OPTION);
            ERR_add_error_data(2, "name=", cnf->name);
            return NULL;
        }
    }

    if (!ctx || !ctx->issuer_cert) {
        if (ctx && (ctx->flags == CTX_TEST))
            return AUTHORITY_KEYID_new();
        X509V3err(X509V3_F_V2I_AUTHORITY_KEYID,
                  X509V3_R_NO_ISSUER_CERTIFICATE);
        return NULL;
    }

    cert = ctx->issuer_cert;

    if (keyid) {
        i = X509_get_ext_by_NID(cert, NID_subject_key_identifier, -1);
        if ((i >= 0) && (ext = X509_get_ext(cert, i)))
            ikeyid = X509V3_EXT_d2i(ext);
        if (keyid == 2 && !ikeyid) {
            X509V3err(X509V3_F_V2I_AUTHORITY_KEYID,
                      X509V3_R_UNABLE_TO_GET_ISSUER_KEYID);
            return NULL;
        }
    }

    if ((issuer && !ikeyid) || (issuer == 2)) {
        isname = X509_NAME_dup(X509_get_issuer_name(cert));
        serial = ASN1_INTEGER_dup(X509_get_serialNumber(cert));
        if (!isname || !serial) {
            X509V3err(X509V3_F_V2I_AUTHORITY_KEYID,
                      X509V3_R_UNABLE_TO_GET_ISSUER_DETAILS);
            goto err;
        }
    }

    if ((akeyid = AUTHORITY_KEYID_new()) == NULL)
        goto err;

    if (isname) {
        if ((gens = sk_GENERAL_NAME_new_null()) == NULL
            || (gen = GENERAL_NAME_new()) == NULL
            || !sk_GENERAL_NAME_push(gens, gen)) {
            X509V3err(X509V3_F_V2I_AUTHORITY_KEYID, 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);
    return NULL;
}