static int x509_get_ext_key_usage( unsigned char **p,
                               const unsigned char *end,
                               mbedtls_x509_sequence *ext_key_usage)
{
    int ret;

    if( ( ret = mbedtls_asn1_get_sequence_of( p, end, ext_key_usage, MBEDTLS_ASN1_OID ) ) != 0 )
        return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS + ret );

    /* Sequence length must be >= 1 */
    if( ext_key_usage->buf.p == NULL )
        return( MBEDTLS_ERR_X509_INVALID_EXTENSIONS +
                MBEDTLS_ERR_ASN1_INVALID_LENGTH );

    return( 0 );
}

When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.