Given the following code containing errors, provide Common Weakness Enumeration (CWE) identifiers and corresponding messages in JSON format. Each identified weakness should have a unique entry in the JSON array.
    Code: unsigned char *ssl_add_serverhello_tlsext(SSL *s, unsigned char *buf,
                                          unsigned char *limit, int *al)
{
    int extdatalen = 0;
    unsigned char *orig = buf;
    unsigned char *ret = buf;
#ifndef OPENSSL_NO_NEXTPROTONEG
    int next_proto_neg_seen;
#endif
#ifndef OPENSSL_NO_EC
    unsigned long alg_k = s->s3->tmp.new_cipher->algorithm_mkey;
    unsigned long alg_a = s->s3->tmp.new_cipher->algorithm_auth;
    int using_ecc = (alg_k & SSL_kECDHE) || (alg_a & SSL_aECDSA);
    using_ecc = using_ecc && (s->session->tlsext_ecpointformatlist != NULL);
#endif

    ret += 2;
    if (ret >= limit)
        return NULL;            /* this really never occurs, but ... */

    if (s->s3->send_connection_binding) {
        int el;

        if (!ssl_add_serverhello_renegotiate_ext(s, 0, &el, 0)) {
            SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
            return NULL;
        }

        /*-
         * check for enough space.
         * 4 bytes for the reneg type and extension length
         * + reneg data length
         */
        if (CHECKLEN(ret, 4 + el, limit))
            return NULL;

        s2n(TLSEXT_TYPE_renegotiate, ret);
        s2n(el, ret);

        if (!ssl_add_serverhello_renegotiate_ext(s, ret, &el, el)) {
            SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
            return NULL;
        }

        ret += el;
    }

    /* Only add RI for SSLv3 */
    if (s->version == SSL3_VERSION)
        goto done;

    if (!s->hit && s->servername_done == 1
        && s->session->tlsext_hostname != NULL) {
        /*-
         * check for enough space.
         * 4 bytes for the server name type and extension length
         */
        if (CHECKLEN(ret, 4, limit))
            return NULL;

        s2n(TLSEXT_TYPE_server_name, ret);
        s2n(0, ret);
    }
#ifndef OPENSSL_NO_EC
    if (using_ecc) {
        const unsigned char *plist;
        size_t plistlen;
        /*
         * Add TLS extension ECPointFormats to the ServerHello message
         */

        tls1_get_formatlist(s, &plist, &plistlen);

        if (plistlen > 255) {
            SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
            return NULL;
        }

        /*-
         * check for enough space.
         * 4 bytes for the ec points format type and extension length
         * 1 byte for the points format list length
         * + length of points format list
         */
        if (CHECKLEN(ret, 5 + plistlen, limit))
            return NULL;

        s2n(TLSEXT_TYPE_ec_point_formats, ret);
        s2n(plistlen + 1, ret);
        *(ret++) = (unsigned char)plistlen;
        memcpy(ret, plist, plistlen);
        ret += plistlen;

    }
    /*
     * Currently the server should not respond with a SupportedCurves
     * extension
     */
#endif                          /* OPENSSL_NO_EC */

    if (s->tlsext_ticket_expected && tls_use_ticket(s)) {
        /*-
         * check for enough space.
         * 4 bytes for the Ticket type and extension length
         */
        if (CHECKLEN(ret, 4, limit))
            return NULL;
        s2n(TLSEXT_TYPE_session_ticket, ret);
        s2n(0, ret);
    } else {
        /*
         * if we don't add the above TLSEXT, we can't add a session ticket
         * later
         */
        s->tlsext_ticket_expected = 0;
    }

    if (s->tlsext_status_expected) {
        /*-
         * check for enough space.
         * 4 bytes for the Status request type and extension length
         */
        if (CHECKLEN(ret, 4, limit))
            return NULL;
        s2n(TLSEXT_TYPE_status_request, ret);
        s2n(0, ret);
    }
#ifndef OPENSSL_NO_SRTP
    if (SSL_IS_DTLS(s) && s->srtp_profile) {
        int el;

        /* Returns 0 on success!! */
        if (ssl_add_serverhello_use_srtp_ext(s, 0, &el, 0)) {
            SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
            return NULL;
        }
        /*-
         * check for enough space.
         * 4 bytes for the SRTP profiles type and extension length
         * + length of the SRTP profiles list
         */
        if (CHECKLEN(ret, 4 + el, limit))
            return NULL;

        s2n(TLSEXT_TYPE_use_srtp, ret);
        s2n(el, ret);

        if (ssl_add_serverhello_use_srtp_ext(s, ret, &el, el)) {
            SSLerr(SSL_F_SSL_ADD_SERVERHELLO_TLSEXT, ERR_R_INTERNAL_ERROR);
            return NULL;
        }
        ret += el;
    }
#endif

    if (((s->s3->tmp.new_cipher->id & 0xFFFF) == 0x80
         || (s->s3->tmp.new_cipher->id & 0xFFFF) == 0x81)
        && (SSL_get_options(s) & SSL_OP_CRYPTOPRO_TLSEXT_BUG)) {
        const unsigned char cryptopro_ext[36] = {
            0xfd, 0xe8,         /* 65000 */
            0x00, 0x20,         /* 32 bytes length */
            0x30, 0x1e, 0x30, 0x08, 0x06, 0x06, 0x2a, 0x85,
            0x03, 0x02, 0x02, 0x09, 0x30, 0x08, 0x06, 0x06,
            0x2a, 0x85, 0x03, 0x02, 0x02, 0x16, 0x30, 0x08,
            0x06, 0x06, 0x2a, 0x85, 0x03, 0x02, 0x02, 0x17
        };

        /* check for enough space. */
        if (CHECKLEN(ret, sizeof(cryptopro_ext), limit))
            return NULL;
        memcpy(ret, cryptopro_ext, sizeof(cryptopro_ext));
        ret += sizeof(cryptopro_ext);

    }
#ifndef OPENSSL_NO_HEARTBEATS
    /* Add Heartbeat extension if we've received one */
    if (SSL_IS_DTLS(s) && (s->tlsext_heartbeat & SSL_DTLSEXT_HB_ENABLED)) {
        /*-
         * check for enough space.
         * 4 bytes for the Heartbeat type and extension length
         * 1 byte for the mode
         */
        if (CHECKLEN(ret, 5, limit))
            return NULL;
        s2n(TLSEXT_TYPE_heartbeat, ret);
        s2n(1, ret);
        /*-
         * Set mode:
         * 1: peer may send requests
         * 2: peer not allowed to send requests
         */
        if (s->tlsext_heartbeat & SSL_DTLSEXT_HB_DONT_RECV_REQUESTS)
            *(ret++) = SSL_DTLSEXT_HB_DONT_SEND_REQUESTS;
        else
            *(ret++) = SSL_DTLSEXT_HB_ENABLED;

    }
#endif

#ifndef OPENSSL_NO_NEXTPROTONEG
    next_proto_neg_seen = s->s3->next_proto_neg_seen;
    s->s3->next_proto_neg_seen = 0;
    if (next_proto_neg_seen && s->ctx->next_protos_advertised_cb) {
        const unsigned char *npa;
        unsigned int npalen;
        int r;

        r = s->ctx->next_protos_advertised_cb(s, &npa, &npalen,
                                              s->
                                              ctx->next_protos_advertised_cb_arg);
        if (r == SSL_TLSEXT_ERR_OK) {
            /*-
             * check for enough space.
             * 4 bytes for the NPN type and extension length
             * + length of protocols list
             */
            if (CHECKLEN(ret, 4 + npalen, limit))
                return NULL;
            s2n(TLSEXT_TYPE_next_proto_neg, ret);
            s2n(npalen, ret);
            memcpy(ret, npa, npalen);
            ret += npalen;
            s->s3->next_proto_neg_seen = 1;
        }
    }
#endif
    if (!custom_ext_add(s, 1, &ret, limit, al))
        return NULL;
    if (s->s3->flags & TLS1_FLAGS_ENCRYPT_THEN_MAC) {
        /*
         * Don't use encrypt_then_mac if AEAD or RC4 might want to disable
         * for other cases too.
         */
        if (SSL_IS_DTLS(s) || s->s3->tmp.new_cipher->algorithm_mac == SSL_AEAD
            || s->s3->tmp.new_cipher->algorithm_enc == SSL_RC4
            || s->s3->tmp.new_cipher->algorithm_enc == SSL_eGOST2814789CNT
            || s->s3->tmp.new_cipher->algorithm_enc == SSL_eGOST2814789CNT12)
            s->s3->flags &= ~TLS1_FLAGS_ENCRYPT_THEN_MAC;
        else {
            /*-
             * check for enough space.
             * 4 bytes for the ETM type and extension length
             */
            if (CHECKLEN(ret, 4, limit))
                return NULL;
            s2n(TLSEXT_TYPE_encrypt_then_mac, ret);
            s2n(0, ret);
        }
    }
    if (s->s3->flags & TLS1_FLAGS_RECEIVED_EXTMS) {
        /*-
         * check for enough space.
         * 4 bytes for the EMS type and extension length
         */
        if (CHECKLEN(ret, 4, limit))
            return NULL;
        s2n(TLSEXT_TYPE_extended_master_secret, ret);
        s2n(0, ret);
    }

    if (s->s3->alpn_selected != NULL) {
        const unsigned char *selected = s->s3->alpn_selected;
        size_t len = s->s3->alpn_selected_len;

        /*-
         * check for enough space.
         * 4 bytes for the ALPN type and extension length
         * 2 bytes for ALPN data length
         * 1 byte for selected protocol length
         * + length of the selected protocol
         */
        if (CHECKLEN(ret, 7 + len, limit))
            return NULL;
        s2n(TLSEXT_TYPE_application_layer_protocol_negotiation, ret);
        s2n(3 + len, ret);
        s2n(1 + len, ret);
        *ret++ = len;
        memcpy(ret, selected, len);
        ret += len;
    }

 done:

    if ((extdatalen = ret - orig - 2) == 0)
        return orig;

    s2n(extdatalen, orig);
    return ret;
} ; Sample JSON Format Confermily Expected output: "examples" => "cwe": "xxx"; "message": "xxx"
    
 'cwe': ['CWE-20'], 'message': 'Don't change the state of the ETM flags until CCS processing

Changing the ciphersuite during a renegotiation can result in a crash
leading to a DoS attack. ETM has not been implemented in 1.1.0 for DTLS
so this is TLS only.

The problem is caused by changing the flag indicating whether to use ETM
or not immediately on negotiation of ETM, rather than at CCS. Therefore,
during a renegotiation, if the ETM state is changing (usually due to a
change of ciphersuite), then an error/crash will occur.

Due to the fact that there are separate CCS messages for read and write
we actually now need two flags to determine whether to use ETM or not.

CVE-2017-3733

Reviewed-by: Richard Levitte <levitte@openssl.org>'