/*

 * Copyright 2007-2023 The OpenSSL Project Authors. All Rights Reserved.

 * Copyright Nokia 2007-2019

 * Copyright Siemens AG 2015-2019

 *

 * 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 "cmp_local.h"

#include "crypto/asn1.h"

/* explicit #includes not strictly needed since implied by the above: */

#include <openssl/asn1t.h>

#include <openssl/cmp.h>

#include <openssl/crmf.h>

#include <openssl/err.h>

#include <openssl/x509.h>

/*

 * This function is also used by the internal verify_PBMAC() in cmp_vfy.c.

 *

 * Calculate protection for |msg| according to |msg->header->protectionAlg|

 * using the credentials, library context, and property criteria in the ctx.

 * Unless |msg->header->protectionAlg| is PasswordBasedMAC,

 * its value is completed according to |ctx->pkey| and |ctx->digest|,

 * where the latter irrelevant in the case of Edwards curves.

 *

 * returns ASN1_BIT_STRING representing the protection on success, else NULL

 */

ASN1_BIT_STRING *ossl_cmp_calc_protection(const OSSL_CMP_CTX *ctx,

                                          const OSSL_CMP_MSG *msg)

{

    ASN1_BIT_STRING *prot = NULL;

    OSSL_CMP_PROTECTEDPART prot_part;

    const ASN1_OBJECT *algorOID = NULL;

    const void *ppval = NULL;

    int pptype = 0;

    if (!ossl_assert(ctx != NULL && msg != NULL))

        return NULL;

    /* construct data to be signed */

    prot_part.header = msg->header;

    prot_part.body = msg->body;

    if (msg->header->protectionAlg == NULL) {

        ERR_raise(ERR_LIB_CMP, CMP_R_UNKNOWN_ALGORITHM_ID);

        return NULL;

    }

    X509_ALGOR_get0(&algorOID, &pptype, &ppval, msg->header->protectionAlg);

    if (OBJ_obj2nid(algorOID) == NID_id_PasswordBasedMAC) {

        int len;

        size_t prot_part_der_len;

        unsigned char *prot_part_der = NULL;

        size_t sig_len;

        unsigned char *protection = NULL;

        OSSL_CRMF_PBMPARAMETER *pbm = NULL;

        ASN1_STRING *pbm_str = NULL;

        const unsigned char *pbm_str_uc = NULL;

        if (ctx->secretValue == NULL) {

            ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PBM_SECRET);

            return NULL;

        }

        if (ppval == NULL) {

            ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_CALCULATING_PROTECTION);

            return NULL;

        }

        len = i2d_OSSL_CMP_PROTECTEDPART(&prot_part, &prot_part_der);

        if (len < 0 || prot_part_der == NULL) {

            ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_CALCULATING_PROTECTION);

            goto end;

        }

        prot_part_der_len = (size_t)len;

        pbm_str = (ASN1_STRING *)ppval;

        pbm_str_uc = pbm_str->data;

        pbm = d2i_OSSL_CRMF_PBMPARAMETER(NULL, &pbm_str_uc, pbm_str->length);

        if (pbm == NULL) {

            ERR_raise(ERR_LIB_CMP, CMP_R_WRONG_ALGORITHM_OID);

            goto end;

        }

        if (!OSSL_CRMF_pbm_new(ctx->libctx, ctx->propq,

                               pbm, prot_part_der, prot_part_der_len,

                               ctx->secretValue->data, ctx->secretValue->length,

                               &protection, &sig_len))

            goto end;

        if ((prot = ASN1_BIT_STRING_new()) == NULL)

            goto end;

        /* OpenSSL by default encodes all bit strings as ASN.1 NamedBitList */

        ossl_asn1_string_set_bits_left(prot, 0);

        if (!ASN1_BIT_STRING_set(prot, protection, sig_len)) {

            ASN1_BIT_STRING_free(prot);

            prot = NULL;

        }

    end:

        OSSL_CRMF_PBMPARAMETER_free(pbm);

        OPENSSL_free(protection);

        OPENSSL_free(prot_part_der);

        return prot;

    } else {

        const EVP_MD *md = ctx->digest;

        char name[80] = "";

        if (ctx->pkey == NULL) {

            ERR_raise(ERR_LIB_CMP,

                      CMP_R_MISSING_KEY_INPUT_FOR_CREATING_PROTECTION);

            return NULL;

        }

        if (EVP_PKEY_get_default_digest_name(ctx->pkey, name, sizeof(name)) > 0

            && strcmp(name, "UNDEF") == 0) /* at least for Ed25519, Ed448 */

            md = NULL;

        if ((prot = ASN1_BIT_STRING_new()) == NULL)

            return NULL;

        if (ASN1_item_sign_ex(ASN1_ITEM_rptr(OSSL_CMP_PROTECTEDPART),

                              msg->header->protectionAlg, /* sets X509_ALGOR */

                              NULL, prot, &prot_part, NULL, ctx->pkey, md,

                              ctx->libctx, ctx->propq))

            return prot;

        ASN1_BIT_STRING_free(prot);

        return NULL;

    }

}

/* ctx is not const just because ctx->chain may get adapted */

int ossl_cmp_msg_add_extraCerts(OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg)

{

    if (!ossl_assert(ctx != NULL && msg != NULL))

        return 0;

    /* Add first ctx->cert and its chain if using signature-based protection */

    if (!ctx->unprotectedSend && ctx->secretValue == NULL

            && ctx->cert != NULL && ctx->pkey != NULL) {

        int prepend = X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP

            | X509_ADD_FLAG_PREPEND | X509_ADD_FLAG_NO_SS;

        /* if not yet done try to build chain using available untrusted certs */

        if (ctx->chain == NULL) {

            ossl_cmp_debug(ctx,

                           "trying to build chain for own CMP signer cert");

            ctx->chain = X509_build_chain(ctx->cert, ctx->untrusted, NULL, 0,

                                          ctx->libctx, ctx->propq);

            if (ctx->chain != NULL) {

                ossl_cmp_debug(ctx,

                               "success building chain for own CMP signer cert");

            } else {

                /* dump errors to avoid confusion when printing further ones */

                OSSL_CMP_CTX_print_errors(ctx);

                ossl_cmp_warn(ctx,

                              "could not build chain for own CMP signer cert");

            }

        }

        if (ctx->chain != NULL) {

            if (!ossl_x509_add_certs_new(&msg->extraCerts, ctx->chain, prepend))

                return 0;

        } else {

            /* make sure that at least our own signer cert is included first */

            if (!ossl_x509_add_cert_new(&msg->extraCerts, ctx->cert, prepend))

                return 0;

            ossl_cmp_debug(ctx, "fallback: adding just own CMP signer cert");

        }

    }

    /* add any additional certificates from ctx->extraCertsOut */

    if (!ossl_x509_add_certs_new(&msg->extraCerts, ctx->extraCertsOut,

                                 X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP))

        return 0;

    /* in case extraCerts are empty list avoid empty ASN.1 sequence */

    if (sk_X509_num(msg->extraCerts) == 0) {

        sk_X509_free(msg->extraCerts);

        msg->extraCerts = NULL;

    }

    return 1;

}

/*

 * Create an X509_ALGOR structure for PasswordBasedMAC protection based on

 * the pbm settings in the context

 */

static X509_ALGOR *pbmac_algor(const OSSL_CMP_CTX *ctx)

{

    OSSL_CRMF_PBMPARAMETER *pbm = NULL;

    unsigned char *pbm_der = NULL;

    int pbm_der_len;

    ASN1_STRING *pbm_str = NULL;

    X509_ALGOR *alg = NULL;

    if (!ossl_assert(ctx != NULL))

        return NULL;

    pbm = OSSL_CRMF_pbmp_new(ctx->libctx, ctx->pbm_slen,

                             EVP_MD_get_type(ctx->pbm_owf), ctx->pbm_itercnt,

                             ctx->pbm_mac);

    pbm_str = ASN1_STRING_new();

    if (pbm == NULL || pbm_str == NULL)

        goto err;

    if ((pbm_der_len = i2d_OSSL_CRMF_PBMPARAMETER(pbm, &pbm_der)) < 0)

        goto err;

    if (!ASN1_STRING_set(pbm_str, pbm_der, pbm_der_len))

        goto err;

    alg = ossl_X509_ALGOR_from_nid(NID_id_PasswordBasedMAC,

                                   V_ASN1_SEQUENCE, pbm_str);

 err:

    if (alg == NULL)

        ASN1_STRING_free(pbm_str);

    OPENSSL_free(pbm_der);

    OSSL_CRMF_PBMPARAMETER_free(pbm);

    return alg;

}

static int set_senderKID(const OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg,

                         const ASN1_OCTET_STRING *id)

{

    if (id == NULL)

        id = ctx->referenceValue; /* standard for PBM, fallback for sig-based */

    return id == NULL || ossl_cmp_hdr_set1_senderKID(msg->header, id);

}

/* ctx is not const just because ctx->chain may get adapted */

int ossl_cmp_msg_protect(OSSL_CMP_CTX *ctx, OSSL_CMP_MSG *msg)

{

    if (!ossl_assert(ctx != NULL && msg != NULL))

        return 0;

    /*

     * For the case of re-protection remove pre-existing protection.

     * Does not remove any pre-existing extraCerts.

     */

    X509_ALGOR_free(msg->header->protectionAlg);

    msg->header->protectionAlg = NULL;

    ASN1_BIT_STRING_free(msg->protection);

    msg->protection = NULL;

    if (ctx->unprotectedSend) {

        if (!set_senderKID(ctx, msg, NULL))

            goto err;

    } else if (ctx->secretValue != NULL) {

        /* use PasswordBasedMac according to 5.1.3.1 if secretValue is given */

        if ((msg->header->protectionAlg = pbmac_algor(ctx)) == NULL)

            goto err;

        if (!set_senderKID(ctx, msg, NULL))

            goto err;

        /*

         * will add any additional certificates from ctx->extraCertsOut

         * while not needed to validate the protection certificate,

         * the option to do this might be handy for certain use cases

         */

    } else if (ctx->cert != NULL && ctx->pkey != NULL) {

        /* use MSG_SIG_ALG according to 5.1.3.3 if client cert and key given */

        /* make sure that key and certificate match */

        if (!X509_check_private_key(ctx->cert, ctx->pkey)) {

            ERR_raise(ERR_LIB_CMP, CMP_R_CERT_AND_KEY_DO_NOT_MATCH);

            goto err;

        }

        if ((msg->header->protectionAlg = X509_ALGOR_new()) == NULL)

            goto err;

        /* set senderKID to keyIdentifier of the cert according to 5.1.1 */

        if (!set_senderKID(ctx, msg, X509_get0_subject_key_id(ctx->cert)))

            goto err;

        /*

         * will add ctx->cert followed, if possible, by its chain built

         * from ctx->untrusted, and then ctx->extraCertsOut

         */

    } else {

        ERR_raise(ERR_LIB_CMP,

                  CMP_R_MISSING_KEY_INPUT_FOR_CREATING_PROTECTION);

        goto err;

    }

    if (!ctx->unprotectedSend

        /* protect according to msg->header->protectionAlg partly set above */

            && ((msg->protection = ossl_cmp_calc_protection(ctx, msg)) == NULL))

        goto err;

    /*

     * For signature-based protection add ctx->cert followed by its chain.

     * Finally add any additional certificates from ctx->extraCertsOut;

     * even if not needed to validate the protection

     * the option to do this might be handy for certain use cases.

     */

    if (!ossl_cmp_msg_add_extraCerts(ctx, msg))

        goto err;

    /*

     * As required by RFC 4210 section 5.1.1., if the sender name is not known

     * to the client it set to NULL-DN. In this case for identification at least

     * the senderKID must be set, where we took the referenceValue as fallback.

     */

    if (!(ossl_cmp_general_name_is_NULL_DN(msg->header->sender)

          && msg->header->senderKID == NULL))

        return 1;

    ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_SENDER_IDENTIFICATION);

 err:

    ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_PROTECTING_MESSAGE);

    return 0;

}