/*

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

 * Copyright Nokia 2007-2020

 * Copyright Siemens AG 2015-2020

 *

 * 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

 */

/* CMP functions for PKIMessage checking */

#include "cmp_local.h"

#include <openssl/cmp_util.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>

/* Verify a message protected by signature according to RFC section 5.1.3.3 */

static int verify_signature(const OSSL_CMP_CTX *cmp_ctx,

                            const OSSL_CMP_MSG *msg, X509 *cert)

{

    OSSL_CMP_PROTECTEDPART prot_part;

    EVP_PKEY *pubkey = NULL;

    BIO *bio;

    int res = 0;

    if (!ossl_assert(cmp_ctx != NULL && msg != NULL && cert != NULL))

        return 0;

    bio = BIO_new(BIO_s_mem()); /* may be NULL */

    /* verify that keyUsage, if present, contains digitalSignature */

    if (!cmp_ctx->ignore_keyusage

            && (X509_get_key_usage(cert) & X509v3_KU_DIGITAL_SIGNATURE) == 0) {

        ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_KEY_USAGE_DIGITALSIGNATURE);

        goto sig_err;

    }

    pubkey = X509_get_pubkey(cert);

    if (pubkey == NULL) {

        ERR_raise(ERR_LIB_CMP, CMP_R_FAILED_EXTRACTING_PUBKEY);

        goto sig_err;

    }

    prot_part.header = msg->header;

    prot_part.body = msg->body;

    if (ASN1_item_verify_ex(ASN1_ITEM_rptr(OSSL_CMP_PROTECTEDPART),

                            msg->header->protectionAlg, msg->protection,

                            &prot_part, NULL, pubkey, cmp_ctx->libctx,

                            cmp_ctx->propq) > 0) {

        res = 1;

        goto end;

    }

 sig_err:

    res = ossl_x509_print_ex_brief(bio, cert, X509_FLAG_NO_EXTENSIONS);

    ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_VALIDATING_SIGNATURE);

    if (res)

        ERR_add_error_mem_bio("\n", bio);

    res = 0;

 end:

    EVP_PKEY_free(pubkey);

    BIO_free(bio);

    return res;

}

/* Verify a message protected with PBMAC */

static int verify_PBMAC(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)

{

    ASN1_BIT_STRING *protection = NULL;

    int valid = 0;

    /* generate expected protection for the message */

    if ((protection = ossl_cmp_calc_protection(ctx, msg)) == NULL)

        return 0; /* failed to generate protection string! */

    valid = msg->protection != NULL && msg->protection->length >= 0

            && msg->protection->type == protection->type

            && msg->protection->length == protection->length

            && CRYPTO_memcmp(msg->protection->data, protection->data,

                             protection->length) == 0;

    ASN1_BIT_STRING_free(protection);

    if (!valid)

        ERR_raise(ERR_LIB_CMP, CMP_R_WRONG_PBM_VALUE);

    return valid;

}

/*-

 * Attempt to validate certificate and path using any given store with trusted

 * certs (possibly including CRLs and a cert verification callback function)

 * and non-trusted intermediate certs from the given ctx.

 *

 * Returns 1 on successful validation and 0 otherwise.

 */

int OSSL_CMP_validate_cert_path(const OSSL_CMP_CTX *ctx,

                                X509_STORE *trusted_store, X509 *cert)

{

    int valid = 0;

    X509_STORE_CTX *csc = NULL;

    int err;

    if (ctx == NULL || cert == NULL) {

        ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);

        return 0;

    }

    if (trusted_store == NULL) {

        ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_TRUST_STORE);

        return 0;

    }

    if ((csc = X509_STORE_CTX_new_ex(ctx->libctx, ctx->propq)) == NULL

            || !X509_STORE_CTX_init(csc, trusted_store,

                                    cert, ctx->untrusted))

        goto err;

    valid = X509_verify_cert(csc) > 0;

    /* make sure suitable error is queued even if callback did not do */

    err = ERR_peek_last_error();

    if (!valid && ERR_GET_REASON(err) != CMP_R_POTENTIALLY_INVALID_CERTIFICATE)

        ERR_raise(ERR_LIB_CMP, CMP_R_POTENTIALLY_INVALID_CERTIFICATE);

 err:

    /* directly output any fresh errors, needed for check_msg_find_cert() */

    OSSL_CMP_CTX_print_errors(ctx);

    X509_STORE_CTX_free(csc);

    return valid;

}

/* Return 0 if expect_name != NULL and there is no matching actual_name */

static int check_name(const OSSL_CMP_CTX *ctx, int log_success,

                      const char *actual_desc, const X509_NAME *actual_name,

                      const char *expect_desc, const X509_NAME *expect_name)

{

    char *str;

    if (expect_name == NULL)

        return 1; /* no expectation, thus trivially fulfilled */

    /* make sure that a matching name is there */

    if (actual_name == NULL) {

        ossl_cmp_log1(WARN, ctx, "missing %s", actual_desc);

        return 0;

    }

    str = X509_NAME_oneline(actual_name, NULL, 0);

    if (X509_NAME_cmp(actual_name, expect_name) == 0) {

        if (log_success && str != NULL)

            ossl_cmp_log2(INFO, ctx, " subject matches %s: %s", expect_desc,

                          str);

        OPENSSL_free(str);

        return 1;

    }

    if (str != NULL)

        ossl_cmp_log2(INFO, ctx, " actual name in %s = %s", actual_desc, str);

    OPENSSL_free(str);

    if ((str = X509_NAME_oneline(expect_name, NULL, 0)) != NULL)

        ossl_cmp_log2(INFO, ctx, " does not match %s = %s", expect_desc, str);

    OPENSSL_free(str);

    return 0;

}

/* Return 0 if skid != NULL and there is no matching subject key ID in cert */

static int check_kid(const OSSL_CMP_CTX *ctx,

                     const ASN1_OCTET_STRING *ckid,

                     const ASN1_OCTET_STRING *skid)

{

    char *str;

    if (skid == NULL)

        return 1; /* no expectation, thus trivially fulfilled */

    /* make sure that the expected subject key identifier is there */

    if (ckid == NULL) {

        ossl_cmp_warn(ctx, "missing Subject Key Identifier in certificate");

        return 0;

    }

    str = OPENSSL_buf2hexstr(ckid->data, ckid->length);

    if (ASN1_OCTET_STRING_cmp(ckid, skid) == 0) {

        if (str != NULL)

            ossl_cmp_log1(INFO, ctx, " subjectKID matches senderKID: %s", str);

        OPENSSL_free(str);

        return 1;

    }

    if (str != NULL)

        ossl_cmp_log1(INFO, ctx, " cert Subject Key Identifier = %s", str);

    OPENSSL_free(str);

    if ((str = OPENSSL_buf2hexstr(skid->data, skid->length)) != NULL)

        ossl_cmp_log1(INFO, ctx, " does not match senderKID    = %s", str);

    OPENSSL_free(str);

    return 0;

}

static int already_checked(const X509 *cert,

                           const STACK_OF(X509) *already_checked)

{

    int i;

    for (i = sk_X509_num(already_checked /* may be NULL */); i > 0; i--)

        if (X509_cmp(sk_X509_value(already_checked, i - 1), cert) == 0)

            return 1;

    return 0;

}

/*-

 * Check if the given cert is acceptable as sender cert of the given message.

 * The subject DN must match, the subject key ID as well if present in the msg,

 * and the cert must be current (checked if ctx->trusted is not NULL).

 * Note that cert revocation etc. is checked by OSSL_CMP_validate_cert_path().

 *

 * Returns 0 on error or not acceptable, else 1.

 */

static int cert_acceptable(const OSSL_CMP_CTX *ctx,

                           const char *desc1, const char *desc2, X509 *cert,

                           const STACK_OF(X509) *already_checked1,

                           const STACK_OF(X509) *already_checked2,

                           const OSSL_CMP_MSG *msg)

{

    X509_STORE *ts = ctx->trusted;

    int self_issued = X509_check_issued(cert, cert) == X509_V_OK;

    char *str;

    X509_VERIFY_PARAM *vpm = ts != NULL ? X509_STORE_get0_param(ts) : NULL;

    int time_cmp;

    ossl_cmp_log3(INFO, ctx, " considering %s%s %s with..",

                  self_issued ? "self-issued ": "", desc1, desc2);

    if ((str = X509_NAME_oneline(X509_get_subject_name(cert), NULL, 0)) != NULL)

        ossl_cmp_log1(INFO, ctx, "  subject = %s", str);

    OPENSSL_free(str);

    if (!self_issued) {

        str = X509_NAME_oneline(X509_get_issuer_name(cert), NULL, 0);

        if (str != NULL)

            ossl_cmp_log1(INFO, ctx, "  issuer  = %s", str);

        OPENSSL_free(str);

    }

    if (already_checked(cert, already_checked1)

            || already_checked(cert, already_checked2)) {

        ossl_cmp_info(ctx, " cert has already been checked");

        return 0;

    }

    time_cmp = X509_cmp_timeframe(vpm, X509_get0_notBefore(cert),

                                  X509_get0_notAfter(cert));

    if (time_cmp != 0) {

        ossl_cmp_warn(ctx, time_cmp > 0 ? "cert has expired"

                                        : "cert is not yet valid");

        return 0;

    }

    if (!check_name(ctx, 1,

                    "cert subject", X509_get_subject_name(cert),

                    "sender field", msg->header->sender->d.directoryName))

        return 0;

    if (!check_kid(ctx, X509_get0_subject_key_id(cert), msg->header->senderKID))

        return 0;

    /* prevent misleading error later in case x509v3_cache_extensions() fails */

    if (!ossl_x509v3_cache_extensions(cert)) {

        ossl_cmp_warn(ctx, "cert appears to be invalid");

        return 0;

    }

    if (!verify_signature(ctx, msg, cert)) {

        ossl_cmp_warn(ctx, "msg signature verification failed");

        return 0;

    }

    /* acceptable also if there is no senderKID in msg header */

    ossl_cmp_info(ctx, " cert seems acceptable");

    return 1;

}

static int check_cert_path(const OSSL_CMP_CTX *ctx, X509_STORE *store,

                           X509 *scrt)

{

    if (OSSL_CMP_validate_cert_path(ctx, store, scrt))

        return 1;

    ossl_cmp_warn(ctx,

                  "msg signature validates but cert path validation failed");

    return 0;

}

/*

 * Exceptional handling for 3GPP TS 33.310 [3G/LTE Network Domain Security

 * (NDS); Authentication Framework (AF)], only to use for IP messages

 * and if the ctx option is explicitly set: use self-issued certificates

 * from extraCerts as trust anchor to validate sender cert -

 * provided it also can validate the newly enrolled certificate

 */

static int check_cert_path_3gpp(const OSSL_CMP_CTX *ctx,

                                const OSSL_CMP_MSG *msg, X509 *scrt)

{

    int valid = 0;

    X509_STORE *store;

    if (!ctx->permitTAInExtraCertsForIR)

        return 0;

    if ((store = X509_STORE_new()) == NULL

            || !ossl_cmp_X509_STORE_add1_certs(store, msg->extraCerts,

                                               1 /* self-issued only */))

        goto err;

    /* store does not include CRLs */

    valid = OSSL_CMP_validate_cert_path(ctx, store, scrt);

    if (!valid) {

        ossl_cmp_warn(ctx,

                      "also exceptional 3GPP mode cert path validation failed");

    } else {

        /*

         * verify that the newly enrolled certificate (which assumed rid ==

         * OSSL_CMP_CERTREQID) can also be validated with the same trusted store

         */

        OSSL_CMP_CERTRESPONSE *crep =

            ossl_cmp_certrepmessage_get0_certresponse(msg->body->value.ip,

                                                      OSSL_CMP_CERTREQID);

        X509 *newcrt = ossl_cmp_certresponse_get1_cert(ctx, crep);

        /*

         * maybe better use get_cert_status() from cmp_client.c, which catches

         * errors

         */

        valid = OSSL_CMP_validate_cert_path(ctx, store, newcrt);

        X509_free(newcrt);

    }

 err:

    X509_STORE_free(store);

    return valid;

}

static int check_msg_given_cert(const OSSL_CMP_CTX *ctx, X509 *cert,

                                const OSSL_CMP_MSG *msg)

{

    return cert_acceptable(ctx, "previously validated", "sender cert",

                           cert, NULL, NULL, msg)

        && (check_cert_path(ctx, ctx->trusted, cert)

            || check_cert_path_3gpp(ctx, msg, cert));

}

/*-

 * Try all certs in given list for verifying msg, normally or in 3GPP mode.

 * If already_checked1 == NULL then certs are assumed to be the msg->extraCerts.

 * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().

 */

static int check_msg_with_certs(OSSL_CMP_CTX *ctx, const STACK_OF(X509) *certs,

                                const char *desc,

                                const STACK_OF(X509) *already_checked1,

                                const STACK_OF(X509) *already_checked2,

                                const OSSL_CMP_MSG *msg, int mode_3gpp)

{

    int in_extraCerts = already_checked1 == NULL;

    int n_acceptable_certs = 0;

    int i;

    if (sk_X509_num(certs) <= 0) {

        ossl_cmp_log1(WARN, ctx, "no %s", desc);

        return 0;

    }

    for (i = 0; i < sk_X509_num(certs); i++) { /* certs may be NULL */

        X509 *cert = sk_X509_value(certs, i);

        if (!ossl_assert(cert != NULL))

            return 0;

        if (!cert_acceptable(ctx, "cert from", desc, cert,

                             already_checked1, already_checked2, msg))

            continue;

        n_acceptable_certs++;

        if (mode_3gpp ? check_cert_path_3gpp(ctx, msg, cert)

                      : check_cert_path(ctx, ctx->trusted, cert)) {

            /* store successful sender cert for further msgs in transaction */

            if (!X509_up_ref(cert))

                return 0;

            if (!ossl_cmp_ctx_set0_validatedSrvCert(ctx, cert)) {

                X509_free(cert);

                return 0;

            }

            return 1;

        }

    }

    if (in_extraCerts && n_acceptable_certs == 0)

        ossl_cmp_warn(ctx, "no acceptable cert in extraCerts");

    return 0;

}

/*-

 * Verify msg trying first ctx->untrusted, which should include extraCerts

 * at its front, then trying the trusted certs in truststore (if any) of ctx.

 * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().

 */

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

                               int mode_3gpp)

{

    int ret = 0;

    if (mode_3gpp

            && ((!ctx->permitTAInExtraCertsForIR

                     || OSSL_CMP_MSG_get_bodytype(msg) != OSSL_CMP_PKIBODY_IP)))

        return 0;

    ossl_cmp_info(ctx,

                  mode_3gpp ? "normal mode failed; trying now 3GPP mode trusting extraCerts"

                            : "trying first normal mode using trust store");

    if (check_msg_with_certs(ctx, msg->extraCerts, "extraCerts",

                             NULL, NULL, msg, mode_3gpp))

        return 1;

    if (check_msg_with_certs(ctx, ctx->untrusted, "untrusted certs",

                             msg->extraCerts, NULL, msg, mode_3gpp))

        return 1;

    if (ctx->trusted == NULL) {

        ossl_cmp_warn(ctx, mode_3gpp ? "no self-issued extraCerts"

                                     : "no trusted store");

    } else {

        STACK_OF(X509) *trusted = X509_STORE_get1_all_certs(ctx->trusted);

        ret = check_msg_with_certs(ctx, trusted,

                                   mode_3gpp ? "self-issued extraCerts"

                                             : "certs in trusted store",

                                   msg->extraCerts, ctx->untrusted,

                                   msg, mode_3gpp);

        sk_X509_pop_free(trusted, X509_free);

    }

    return ret;

}

static int no_log_cb(const char *func, const char *file, int line,

                     OSSL_CMP_severity level, const char *msg)

{

    return 1;

}

/*-

 * Verify message signature with any acceptable and valid candidate cert.

 * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().

 */

static int check_msg_find_cert(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)

{

    X509 *scrt = ctx->validatedSrvCert; /* previous successful sender cert */

    GENERAL_NAME *sender = msg->header->sender;

    char *sname = NULL;

    char *skid_str = NULL;

    const ASN1_OCTET_STRING *skid = msg->header->senderKID;

    OSSL_CMP_log_cb_t backup_log_cb = ctx->log_cb;

    int res = 0;

    if (sender == NULL || msg->body == NULL)

        return 0; /* other NULL cases already have been checked */

    if (sender->type != GEN_DIRNAME) {

        ERR_raise(ERR_LIB_CMP, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);

        return 0;

    }

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

    OSSL_CMP_CTX_print_errors(ctx);

    /* enable clearing irrelevant errors in attempts to validate sender certs */

    (void)ERR_set_mark();

    ctx->log_cb = no_log_cb; /* temporarily disable logging */

    /*

     * try first cached scrt, used successfully earlier in same transaction,

     * for validating this and any further msgs where extraCerts may be left out

     */

    if (scrt != NULL) {

        if (check_msg_given_cert(ctx, scrt, msg)) {

            ctx->log_cb = backup_log_cb;

            (void)ERR_pop_to_mark();

            return 1;

        }

        /* cached sender cert has shown to be no more successfully usable */

        (void)ossl_cmp_ctx_set0_validatedSrvCert(ctx, NULL);

        /* re-do the above check (just) for adding diagnostic information */

        ossl_cmp_info(ctx,

                      "trying to verify msg signature with previously validated cert");

        (void)check_msg_given_cert(ctx, scrt, msg);

    }

    res = check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */)

            || check_msg_all_certs(ctx, msg, 1 /* 3gpp */);

    ctx->log_cb = backup_log_cb;

    if (res) {

        /* discard any diagnostic information on trying to use certs */

        (void)ERR_pop_to_mark();

        goto end;

    }

    /* failed finding a sender cert that verifies the message signature */

    (void)ERR_clear_last_mark();

    sname = X509_NAME_oneline(sender->d.directoryName, NULL, 0);

    skid_str = skid == NULL ? NULL

                            : OPENSSL_buf2hexstr(skid->data, skid->length);

    if (ctx->log_cb != NULL) {

        ossl_cmp_info(ctx, "trying to verify msg signature with a valid cert that..");

        if (sname != NULL)

            ossl_cmp_log1(INFO, ctx, "matches msg sender    = %s", sname);

        if (skid_str != NULL)

            ossl_cmp_log1(INFO, ctx, "matches msg senderKID = %s", skid_str);

        else

            ossl_cmp_info(ctx, "while msg header does not contain senderKID");

        /* re-do the above checks (just) for adding diagnostic information */

        (void)check_msg_all_certs(ctx, msg, 0 /* using ctx->trusted */);

        (void)check_msg_all_certs(ctx, msg, 1 /* 3gpp */);

    }

    ERR_raise(ERR_LIB_CMP, CMP_R_NO_SUITABLE_SENDER_CERT);

    if (sname != NULL) {

        ERR_add_error_txt(NULL, "for msg sender name = ");

        ERR_add_error_txt(NULL, sname);

    }

    if (skid_str != NULL) {

        ERR_add_error_txt(" and ", "for msg senderKID = ");

        ERR_add_error_txt(NULL, skid_str);

    }

 end:

    OPENSSL_free(sname);

    OPENSSL_free(skid_str);

    return res;

}

/*-

 * Validate the protection of the given PKIMessage using either password-

 * based mac (PBM) or a signature algorithm. In the case of signature algorithm,

 * the sender certificate can have been pinned by providing it in ctx->srvCert,

 * else it is searched in msg->extraCerts, ctx->untrusted, in ctx->trusted

 * (in this order) and is path is validated against ctx->trusted.

 * On success cache the found cert using ossl_cmp_ctx_set0_validatedSrvCert().

 *

 * If ctx->permitTAInExtraCertsForIR is true and when validating a CMP IP msg,

 * the trust anchor for validating the IP msg may be taken from msg->extraCerts

 * if a self-issued certificate is found there that can be used to

 * validate the enrolled certificate returned in the IP.

 * This is according to the need given in 3GPP TS 33.310.

 *

 * Returns 1 on success, 0 on error or validation failed.

 */

int OSSL_CMP_validate_msg(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg)

{

    X509 *scrt;

    ossl_cmp_debug(ctx, "validating CMP message");

    if (ctx == NULL || msg == NULL

            || msg->header == NULL || msg->body == NULL) {

        ERR_raise(ERR_LIB_CMP, CMP_R_NULL_ARGUMENT);

        return 0;

    }

    if (msg->header->protectionAlg == NULL /* unprotected message */

            || msg->protection == NULL || msg->protection->data == NULL) {

        ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PROTECTION);

        return 0;

    }

    switch (ossl_cmp_hdr_get_protection_nid(msg->header)) {

        /* 5.1.3.1.  Shared Secret Information */

    case NID_id_PasswordBasedMAC:

        if (ctx->secretValue == NULL) {

            ossl_cmp_info(ctx, "no secret available for verifying PBM-based CMP message protection");

            ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_SECRET);

            return 0;

        }

        if (verify_PBMAC(ctx, msg)) {

            /*

             * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is

             * "shared secret information", then any certificate transported in

             * the caPubs field may be directly trusted as a root CA

             * certificate by the initiator.'

             */

            switch (OSSL_CMP_MSG_get_bodytype(msg)) {

            case -1:

                return 0;

            case OSSL_CMP_PKIBODY_IP:

            case OSSL_CMP_PKIBODY_CP:

            case OSSL_CMP_PKIBODY_KUP:

            case OSSL_CMP_PKIBODY_CCP:

                if (ctx->trusted != NULL) {

                    STACK_OF(X509) *certs = msg->body->value.ip->caPubs;

                    /* value.ip is same for cp, kup, and ccp */

                    if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))

                        /* adds both self-issued and not self-issued certs */

                        return 0;

                }

                break;

            default:

                break;

            }

            ossl_cmp_debug(ctx,

                           "successfully validated PBM-based CMP message protection");

            return 1;

        }

        ossl_cmp_warn(ctx, "verifying PBM-based CMP message protection failed");

        break;

        /*

         * 5.1.3.2 DH Key Pairs

         * Not yet supported

         */

    case NID_id_DHBasedMac:

        ERR_raise(ERR_LIB_CMP, CMP_R_UNSUPPORTED_PROTECTION_ALG_DHBASEDMAC);

        break;

        /*

         * 5.1.3.3.  Signature

         */

    default:

        scrt = ctx->srvCert;

        if (scrt == NULL) {

            if (ctx->trusted == NULL) {

                ossl_cmp_info(ctx, "no trust store nor pinned server cert available for verifying signature-based CMP message protection");

                ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_TRUST_ANCHOR);

                return 0;

            }

            if (check_msg_find_cert(ctx, msg))

                return 1;

        } else { /* use pinned sender cert */

            /* use ctx->srvCert for signature check even if not acceptable */

            if (verify_signature(ctx, msg, scrt)) {

                ossl_cmp_debug(ctx,

                               "successfully validated signature-based CMP message protection");

                return 1;

            }

            ossl_cmp_warn(ctx, "CMP message signature verification failed");

            ERR_raise(ERR_LIB_CMP, CMP_R_SRVCERT_DOES_NOT_VALIDATE_MSG);

        }

        break;

    }

    return 0;

}

/*-

 * Check received message (i.e., response by server or request from client)

 * Any msg->extraCerts are prepended to ctx->untrusted.

 *

 * Ensures that:

 * its sender is of appropriate type (currently only X509_NAME) and

 *     matches any expected sender or srvCert subject given in the ctx

 * it has a valid body type

 * its protection is valid (or invalid/absent, but only if a callback function

 *     is present and yields a positive result using also the supplied argument)

 * its transaction ID matches the previous transaction ID stored in ctx (if any)

 * its recipNonce matches the previous senderNonce stored in the ctx (if any)

 *

 * If everything is fine:

 * learns the senderNonce from the received message,

 * learns the transaction ID if it is not yet in ctx,

 * and makes any certs in caPubs directly trusted.

 *

 * Returns 1 on success, 0 on error.

 */

int ossl_cmp_msg_check_update(OSSL_CMP_CTX *ctx, const OSSL_CMP_MSG *msg,

                              ossl_cmp_allow_unprotected_cb_t cb, int cb_arg)

{

    OSSL_CMP_PKIHEADER *hdr;

    const X509_NAME *expected_sender;

    if (!ossl_assert(ctx != NULL && msg != NULL && msg->header != NULL))

        return 0;

    hdr = OSSL_CMP_MSG_get0_header(msg);

    /* validate sender name of received msg */

    if (hdr->sender->type != GEN_DIRNAME) {

        ERR_raise(ERR_LIB_CMP, CMP_R_SENDER_GENERALNAME_TYPE_NOT_SUPPORTED);

        return 0;

    }

    /*

     * Compare actual sender name of response with expected sender name.

     * Mitigates risk to accept misused PBM secret

     * or misused certificate of an unauthorized entity of a trusted hierarchy.

     */

    expected_sender = ctx->expected_sender;

    if (expected_sender == NULL && ctx->srvCert != NULL)

        expected_sender = X509_get_subject_name(ctx->srvCert);

    if (!check_name(ctx, 0, "sender DN field", hdr->sender->d.directoryName,

                    "expected sender", expected_sender))

        return 0;

    /* Note: if recipient was NULL-DN it could be learned here if needed */

    if (sk_X509_num(msg->extraCerts) > 10)

        ossl_cmp_warn(ctx,

                      "received CMP message contains more than 10 extraCerts");

    /*

     * Store any provided extraCerts in ctx for use in OSSL_CMP_validate_msg()

     * and for future use, such that they are available to ctx->certConf_cb and

     * the peer does not need to send them again in the same transaction.

     * Note that it does not help validating the message before storing the

     * extraCerts because they do not belong to the protected msg part anyway.

     * For efficiency, the extraCerts are prepended so they get used first.

     */

    if (!X509_add_certs(ctx->untrusted, msg->extraCerts,

                        /* this allows self-signed certs */

                        X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP

                        | X509_ADD_FLAG_PREPEND))

        return 0;

    /* validate message protection */

    if (hdr->protectionAlg != NULL) {

        /* detect explicitly permitted exceptions for invalid protection */

        if (!OSSL_CMP_validate_msg(ctx, msg)

                && (cb == NULL || (*cb)(ctx, msg, 1, cb_arg) <= 0)) {

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

            ERR_raise(ERR_LIB_CMP, CMP_R_ERROR_VALIDATING_PROTECTION);

            return 0;

#endif

        }

    } else {

        /* detect explicitly permitted exceptions for missing protection */

        if (cb == NULL || (*cb)(ctx, msg, 0, cb_arg) <= 0) {

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

            ERR_raise(ERR_LIB_CMP, CMP_R_MISSING_PROTECTION);

            return 0;

#endif

        }

    }

    /* check CMP version number in header */

    if (ossl_cmp_hdr_get_pvno(hdr) != OSSL_CMP_PVNO) {

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

        ERR_raise(ERR_LIB_CMP, CMP_R_UNEXPECTED_PVNO);

        return 0;

#endif

    }

    if (OSSL_CMP_MSG_get_bodytype(msg) < 0) {

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

        ERR_raise(ERR_LIB_CMP, CMP_R_PKIBODY_ERROR);

        return 0;

#endif

    }

    /* compare received transactionID with the expected one in previous msg */

    if (ctx->transactionID != NULL

            && (hdr->transactionID == NULL

                || ASN1_OCTET_STRING_cmp(ctx->transactionID,

                                         hdr->transactionID) != 0)) {

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

        ERR_raise(ERR_LIB_CMP, CMP_R_TRANSACTIONID_UNMATCHED);

        return 0;

#endif

    }

    /* compare received nonce with the one we sent */

    if (ctx->senderNonce != NULL

            && (msg->header->recipNonce == NULL

                || ASN1_OCTET_STRING_cmp(ctx->senderNonce,

                                         hdr->recipNonce) != 0)) {

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

        ERR_raise(ERR_LIB_CMP, CMP_R_RECIPNONCE_UNMATCHED);

        return 0;

#endif

    }

    /* if not yet present, learn transactionID */

    if (ctx->transactionID == NULL

        && !OSSL_CMP_CTX_set1_transactionID(ctx, hdr->transactionID))

        return 0;

    /*

     * RFC 4210 section 5.1.1 states: the recipNonce is copied from

     * the senderNonce of the previous message in the transaction.

     * --> Store for setting in next message

     */

    if (!ossl_cmp_ctx_set1_recipNonce(ctx, hdr->senderNonce))

        return 0;

    /*

     * Store any provided extraCerts in ctx for future use,

     * such that they are available to ctx->certConf_cb and

     * the peer does not need to send them again in the same transaction.

     * For efficiency, the extraCerts are prepended so they get used first.

     */

    if (!X509_add_certs(ctx->untrusted, msg->extraCerts,

                        /* this allows self-signed certs */

                        X509_ADD_FLAG_UP_REF | X509_ADD_FLAG_NO_DUP

                        | X509_ADD_FLAG_PREPEND))

        return 0;

    if (ossl_cmp_hdr_get_protection_nid(hdr) == NID_id_PasswordBasedMAC) {

        /*

         * RFC 4210, 5.3.2: 'Note that if the PKI Message Protection is

         * "shared secret information", then any certificate transported in

         * the caPubs field may be directly trusted as a root CA

         * certificate by the initiator.'

         */

        switch (OSSL_CMP_MSG_get_bodytype(msg)) {

        case OSSL_CMP_PKIBODY_IP:

        case OSSL_CMP_PKIBODY_CP:

        case OSSL_CMP_PKIBODY_KUP:

        case OSSL_CMP_PKIBODY_CCP:

            if (ctx->trusted != NULL) {

                STACK_OF(X509) *certs = msg->body->value.ip->caPubs;

                /* value.ip is same for cp, kup, and ccp */

                if (!ossl_cmp_X509_STORE_add1_certs(ctx->trusted, certs, 0))

                    /* adds both self-issued and not self-issued certs */

                    return 0;

            }

            break;

        default:

            break;

        }

    }

    return 1;

}

int ossl_cmp_verify_popo(const OSSL_CMP_CTX *ctx,

                         const OSSL_CMP_MSG *msg, int acceptRAVerified)

{

    if (!ossl_assert(msg != NULL && msg->body != NULL))

        return 0;

    switch (msg->body->type) {

    case OSSL_CMP_PKIBODY_P10CR:

        {

            X509_REQ *req = msg->body->value.p10cr;

            if (X509_REQ_verify_ex(req, X509_REQ_get0_pubkey(req), ctx->libctx,

                                   ctx->propq) <= 0) {

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

                ERR_raise(ERR_LIB_CMP, CMP_R_REQUEST_NOT_ACCEPTED);

                return 0;

#endif

            }

        }

        break;

    case OSSL_CMP_PKIBODY_IR:

    case OSSL_CMP_PKIBODY_CR:

    case OSSL_CMP_PKIBODY_KUR:

        if (!OSSL_CRMF_MSGS_verify_popo(msg->body->value.ir, OSSL_CMP_CERTREQID,

                                        acceptRAVerified,

                                        ctx->libctx, ctx->propq)) {

#ifndef FUZZING_BUILD_MODE_UNSAFE_FOR_PRODUCTION

            return 0;

#endif

        }

        break;

    default:

        ERR_raise(ERR_LIB_CMP, CMP_R_PKIBODY_ERROR);

        return 0;

    }

    return 1;

}