ldap_utils/

lib.rs

#![deny(unknown_lints)]
#![deny(renamed_and_removed_lints)]
#![forbid(unsafe_code)]
#![deny(deprecated)]
#![forbid(private_interfaces)]
#![forbid(private_bounds)]
#![forbid(non_fmt_panics)]
#![deny(unreachable_code)]
#![deny(unreachable_patterns)]
#![forbid(unused_doc_comments)]
#![forbid(unused_must_use)]
#![deny(while_true)]
#![deny(unused_parens)]
#![deny(redundant_semicolons)]
#![deny(non_ascii_idents)]
#![deny(confusable_idents)]
#![warn(missing_docs)]
#![warn(clippy::missing_docs_in_private_items)]
#![warn(clippy::cargo_common_metadata)]
#![warn(rustdoc::missing_crate_level_docs)]
#![deny(rustdoc::broken_intra_doc_links)]
#![warn(missing_debug_implementations)]
#![deny(clippy::mod_module_files)]
#![doc = include_str!("../README.md")]

use lazy_static::lazy_static;

use diff::{Diff, VecDiffType};

use chumsky::Parser;
use ldap_types::basic::{ChumskyError, LDAPEntry, LDAPOperation, OIDWithLength, RootDSE};
use ldap_types::schema::{
    attribute_type_parser, ldap_syntax_parser, matching_rule_parser, matching_rule_use_parser,
    object_class_parser, AttributeType, LDAPSchema, LDAPSyntax, MatchingRule, MatchingRuleUse,
    ObjectClass,
};

use ldap3::exop::{WhoAmI, WhoAmIResp};
use ldap3::result::SearchResult;
use ldap3::{Ldap, LdapConnAsync, LdapConnSettings, Scope, SearchEntry};
use native_tls::{Certificate, Identity, TlsConnector};
use oid::ObjectIdentifier;

use std::collections::{HashMap, HashSet};
use std::fmt::Debug;
use std::fmt::Display;

use openssl::pkcs12::Pkcs12;
use openssl::pkey::PKey;
use openssl::x509::X509;

use std::fs::File;
use std::io::Read;
use std::path::Path;

use regex::Regex;

use dirs2::home_dir;

use tracing::instrument;

use derive_builder::Builder;

use serde::Deserialize;

use std::convert::TryInto;

use thiserror::Error;

/// creates a noop_control object for use with ldap3
///
/// the noop_control is supposed to perform the same operation
/// and return the same errors as the real operation but not make
/// any changes to the directory
///
/// OpenLDAP's implementation seems to be buggy, in my tests some uses of the
/// NOOP control lead to problems displaying affected objects until the LDAP
/// server was restarted
pub fn noop_control() -> ldap3::controls::RawControl {
    ldap3::controls::RawControl {
        ctype: "1.3.6.1.4.1.4203.666.5.2".to_string(),
        crit: true,
        val: None,
    }
}

/// error which can occur while parsing a scope
#[derive(Debug, Clone, Error)]
pub enum ScopeParserError {
    /// could not parse the value as a scope
    #[error("Could not parse {0} as an ldap scope")]
    CouldNotParseAsScope(String),
}

/// parse an [ldap3::Scope] from the string one would specify to use the same
/// scope with OpenLDAP's ldapsearch -s parameter
pub fn parse_scope(src: &str) -> Result<ldap3::Scope, ScopeParserError> {
    match src {
        "base" => Ok(ldap3::Scope::Base),
        "one" => Ok(ldap3::Scope::OneLevel),
        "sub" => Ok(ldap3::Scope::Subtree),
        s => Err(ScopeParserError::CouldNotParseAsScope(s.to_string())),
    }
}

/// a set of parameters for connecting to an LDAP server, including client-side
/// certificate auth support
#[derive(Debug, Clone, Builder, Deserialize)]
pub struct ConnectParameters {
    /// CA certificate path
    ca_cert_path: std::string::String,
    /// client certificate path
    client_cert_path: std::string::String,
    /// client key path
    client_key_path: std::string::String,
    /// the LDAP URL to connect to
    pub url: std::string::String,
}

/// errors which can happen when trying to retrieve connect parameters from openldap config
#[derive(Debug, Error)]
pub enum OpenLdapConnectParameterError {
    /// an error when compiling or using a regular expression
    #[error("regex error: {0}")]
    RegexError(#[from] regex::Error),
    /// an I/O error
    #[error("I/O error: {0}")]
    IOError(#[from] std::io::Error),
}

/// try to detect OpenLDAP connect parameters from its config files
/// (ldap.conf in /etc/ldap or /etc/openldap and .ldaprc in the user home dir)
#[instrument(skip(builder))]
pub fn openldap_connect_parameters(
    builder: &mut ConnectParametersBuilder,
) -> Result<&mut ConnectParametersBuilder, OpenLdapConnectParameterError> {
    let ldap_rc_content;
    let ldap_conf_content;
    if let Some(d) = home_dir() {
        let mut ldap_rc_filename = d;
        ldap_rc_filename.push(".ldaprc");
        if ldap_rc_filename.exists() {
            tracing::debug!("Using .ldaprc at {:?}", ldap_rc_filename);
            ldap_rc_content = std::fs::read_to_string(ldap_rc_filename)?;

            let ca_cert_re = Regex::new(r"^TLS_CACERT *(.*)$")?;
            let client_cert_re = Regex::new(r"^TLS_CERT *(.*)$")?;
            let client_key_re = Regex::new(r"^TLS_KEY *(.*)$")?;
            for line in ldap_rc_content.lines() {
                if let Some(caps) = ca_cert_re.captures(line) {
                    let ca_cert_path = caps.get(1).unwrap().as_str();
                    tracing::debug!("Extracted .ldaprc TLS_CACERT value {}", ca_cert_path);
                    builder.ca_cert_path(ca_cert_path.to_string());
                }

                if let Some(caps) = client_cert_re.captures(line) {
                    let client_cert_path = caps.get(1).unwrap().as_str();
                    tracing::debug!("Extracted .ldaprc TLS_CERT value {}", client_cert_path);
                    builder.client_cert_path(client_cert_path.to_string());
                }

                if let Some(caps) = client_key_re.captures(line) {
                    let client_key_path = caps.get(1).unwrap().as_str();
                    tracing::debug!("Extracted .ldaprc TLS_KEY value {}", client_key_path);
                    builder.client_key_path(client_key_path.to_string());
                }
            }
        }

        let mut ldap_conf_filename = Path::new("/etc/ldap/ldap.conf");
        if !ldap_conf_filename.exists() {
            ldap_conf_filename = Path::new("/etc/openldap/ldap.conf");
        }
        if ldap_conf_filename.exists() {
            tracing::debug!("Using ldap.conf at {:?}", ldap_conf_filename);
            ldap_conf_content = std::fs::read_to_string(ldap_conf_filename)?;

            let uri_re = Regex::new(r"^URI *(.*)$")?;
            for line in ldap_conf_content.lines() {
                if let Some(caps) = uri_re.captures(line) {
                    let url = caps.get(1).unwrap().as_str();
                    tracing::debug!("Extracted ldap.conf URI value {}", url);
                    builder.url(url.to_string());
                }
            }
        }
    }
    Ok(builder)
}

/// fill the builder with hardcoded default parameters
///
/// there is no default parameter for the URL
#[instrument(skip(builder))]
pub fn default_connect_parameters(
    builder: &mut ConnectParametersBuilder,
) -> &mut ConnectParametersBuilder {
    if builder.ca_cert_path.is_none() {
        builder.ca_cert_path("ca.crt".to_string());
    }
    if builder.client_cert_path.is_none() {
        builder.client_cert_path("client.crt".to_string());
    }
    if builder.client_key_path.is_none() {
        builder.client_key_path("client.key".to_string());
    }
    builder
}

/// error which can happen while reading connect parameters from a file
#[derive(Debug, Error)]
pub enum TomlConfigError {
    /// an I/O error
    #[error("I/O error: {0}")]
    IOError(#[from] std::io::Error),
    /// an error deserializing the TOML file
    #[error("Toml deserialization error: {0}")]
    TomlError(#[from] toml::de::Error),
}

/// load ldap connect parameters from a toml file
#[instrument]
pub fn toml_connect_parameters(
    filename: std::path::PathBuf,
) -> Result<ConnectParameters, TomlConfigError> {
    let config = std::fs::read_to_string(filename)?;
    let result: ConnectParameters = toml::from_str(&config)?;

    Ok(result)
}

/// errors which can happen when connecting to an LDAP server
#[derive(Debug, Error)]
pub enum ConnectError {
    /// an error when building the parameters, most likely a value
    /// that could not be retrieved from any config source
    #[error("Parameters builder error: {0}")]
    ParametersBuilderError(#[from] ConnectParametersBuilderError),
    /// an error when trying to retrieve connect parameters from OpenLDAP config files
    #[error("Error retrieving OpenLDAP connect parameters: {0}")]
    OpenLdapConnectParameterError(#[from] OpenLdapConnectParameterError),
    /// an I/O error
    #[error("I/O error: {0}")]
    IOError(#[from] std::io::Error),
    /// an error in the native_tls crate
    #[error("Native TLS error: {0}")]
    NativeTLSError(#[from] native_tls::Error),
    /// an error in the ldap3 crate
    #[error("ldap3 Ldap error: {0}")]
    LdapError(#[from] ldap3::LdapError),
    /// an error when compiling or using a regular expression
    #[error("regex error: {0}")]
    RegexError(#[from] regex::Error),
    /// an error in the openssl library used to read certificates and keys
    #[error("openssl error: {0}")]
    OpenSSLError(#[from] openssl::error::ErrorStack),
}

/// try to connect to an LDAP server using ldap3 using the OpenLDAP config files
/// supplemented by hardcoded default values
#[instrument]
pub async fn connect() -> Result<(Ldap, std::string::String), ConnectError> {
    let mut builder = ConnectParametersBuilder::default();
    openldap_connect_parameters(&mut builder)?;
    match builder.build() {
        Ok(result) => connect_with_parameters(result).await,
        Err(err_msg) => {
            tracing::error!(
                "Building of ConnectParameters based on OpenLDAP config files failed: {}",
                err_msg
            );
            let builder = default_connect_parameters(&mut builder);
            match builder.build() {
                Ok(result) => connect_with_parameters(result).await,
                Err(err) => {
                    tracing::error!("Building of ConnectParameters based on OpenLDAP config files and substituting default values for missing values failed: {}", err);
                    Err(ConnectError::ParametersBuilderError(err))
                }
            }
        }
    }
}

/// connect to an LDAP server using ldap3 with the given set of default parameters
#[instrument]
pub async fn connect_with_parameters(
    connect_parameters: ConnectParameters,
) -> Result<(Ldap, std::string::String), ConnectError> {
    let mut client_cert_contents = Vec::new();
    {
        let mut file = File::open(connect_parameters.client_cert_path)?;
        file.read_to_end(&mut client_cert_contents)?;
    }
    let client_cert = X509::from_pem(&client_cert_contents)?;
    let mut client_key_contents = Vec::new();
    {
        let mut file = File::open(connect_parameters.client_key_path)?;
        file.read_to_end(&mut client_key_contents)?;
    }
    let client_key = PKey::private_key_from_pem(&client_key_contents)?;
    let p12_password = "client";
    let p12 = Pkcs12::builder()
        .name("client")
        .pkey(&client_key)
        .cert(&client_cert)
        .build2(p12_password)?;
    let p12_contents = p12.to_der()?;
    let mut ca_cert_contents = Vec::new();
    {
        let mut file = File::open(connect_parameters.ca_cert_path)?;
        file.read_to_end(&mut ca_cert_contents)?;
    }
    let identity = Identity::from_pkcs12(&p12_contents, p12_password)?;
    let ca_certificate = Certificate::from_pem(&ca_cert_contents)?;
    let connector = TlsConnector::builder()
        .identity(identity)
        .add_root_certificate(ca_certificate)
        .build()?;
    let ldap_settings = LdapConnSettings::new().set_connector(connector);
    let (ldap_conn_async, mut ldap) =
        LdapConnAsync::with_settings(ldap_settings, &connect_parameters.url.clone()).await?;
    ldap3::drive!(ldap_conn_async);
    ldap.sasl_external_bind().await?;
    let (exop, _res) = ldap.extended(WhoAmI).await?.success()?;
    let who_am_i: WhoAmIResp = exop.parse();
    let re = Regex::new(r"^.*,ou=[a-z]+,")?;
    let base_dn = re.replace_all(&who_am_i.authzid, "").to_string();
    Ok((ldap, base_dn))
}

/// an error during normal ldap operations (search, add, modify, update, delete,...)
#[derive(Debug, Error)]
pub enum LdapOperationError {
    /// an error in the ldap3 library
    #[error("ldap3 Ldap error: {0}")]
    LdapError(#[from] ldap3::LdapError),
    /// and error parsing an OID
    #[error("OID error: {0}")]
    OIDError(#[from] OIDError),
}

/// perform an LDAP search via ldap3, logging a proper error message if it fails
/// and returning an iterator to already unwrapped search entries
pub async fn ldap_search<'a, S: AsRef<str> + Clone + Display + Debug + Send + Sync>(
    ldap: &mut Ldap,
    base: &str,
    scope: Scope,
    filter: &str,
    attrs: Vec<S>,
) -> Result<Box<dyn Iterator<Item = SearchEntry> + 'a>, LdapOperationError> {
    let search_result = ldap.search(base, scope, filter, attrs.clone()).await?;
    let SearchResult(_rs, res) = &search_result;
    if res.rc != 0 {
        tracing::debug!(
            "Non-zero return code {} in LDAP query\n  base: {}\n  scope: {:?}\n  filter: {}\n  attrs: {:#?}",
            res.rc,
            base,
            scope,
            filter,
            attrs
        );
        tracing::debug!(
            "ldapsearch -Q -LLL -o ldif-wrap=no -b '{}' -s {} '{}' {}",
            base,
            format!("{:?}", scope).to_lowercase(),
            filter,
            itertools::join(attrs.iter(), " ")
        );
    }
    let (rs, _res) = search_result.success()?;
    Ok(Box::new(rs.into_iter().map(SearchEntry::construct)))
}

/// an error type in case parsing an OID fails when querying the RootDSE from ldap3
/// during the parsing of supported controls, extensions and features
#[derive(Debug)]
pub struct OIDError(oid::ObjectIdentifierError);

impl Display for OIDError {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        write!(f, "Error parsing OID: {:?}", self.0)
    }
}

impl std::error::Error for OIDError {
    fn source(&self) -> Option<&(dyn std::error::Error + 'static)> {
        None
    }
}

/// retrieve the [RootDSE] from an LDAP server using ldap3
#[instrument(skip(ldap))]
pub async fn query_root_dse(ldap: &mut Ldap) -> Result<Option<RootDSE>, LdapOperationError> {
    let mut it = ldap_search(
        ldap,
        "",
        Scope::Base,
        "(objectClass=*)",
        vec![
            "supportedLDAPVersion",
            "supportedControl",
            "supportedExtension",
            "supportedFeatures",
            "supportedSASLMechanisms",
            "configContext",
            "namingContexts",
            "subschemaSubentry",
        ],
    )
    .await?;
    if let Some(entry) = it.next() {
        let supported_ldap_version = entry
            .attrs
            .get("supportedLDAPVersion")
            .unwrap()
            .first()
            .unwrap();
        let supported_controls = entry.attrs.get("supportedControl").unwrap();
        let supported_extensions = entry.attrs.get("supportedExtension").unwrap();
        let supported_features = entry.attrs.get("supportedFeatures").unwrap();
        let supported_sasl_mechanisms = entry.attrs.get("supportedSASLMechanisms").unwrap();
        let config_context = entry.attrs.get("configContext").unwrap().first().unwrap();
        let naming_contexts = entry.attrs.get("namingContexts").unwrap();
        let subschema_subentry = entry
            .attrs
            .get("subschemaSubentry")
            .unwrap()
            .first()
            .unwrap();
        return Ok(Some(RootDSE {
            supported_ldap_version: supported_ldap_version.to_string(),
            supported_controls: supported_controls
                .iter()
                .map(|x| x.clone().try_into())
                .collect::<Result<_, _>>()
                .map_err(OIDError)?,
            supported_extensions: supported_extensions
                .iter()
                .map(|x| x.clone().try_into())
                .collect::<Result<_, _>>()
                .map_err(OIDError)?,
            supported_features: supported_features
                .iter()
                .map(|x| x.clone().try_into())
                .collect::<Result<_, _>>()
                .map_err(OIDError)?,
            supported_sasl_mechanisms: supported_sasl_mechanisms.to_vec(),
            config_context: config_context.to_string(),
            naming_contexts: naming_contexts.to_vec(),
            subschema_subentry: subschema_subentry.to_string(),
        }));
    }
    Ok(None)
}

/// error which can happen while retrieving and parsing the LDAP schema
#[derive(Debug, Error)]
pub enum LdapSchemaError {
    /// an error in the ldap operations performed while retrieving the schema
    #[error("Ldap operation error: {0}")]
    LdapOperationError(#[from] LdapOperationError),
    /// an error while parsing the retrieved schema
    #[error("chumsky parser error: {0}")]
    ChumskyError(#[from] ChumskyError),
}

/// Retrieve the LDAP schema from an LDAP server using ldap3
///
/// tested with OpenLDAP
#[instrument(skip(ldap))]
pub async fn query_ldap_schema(ldap: &mut Ldap) -> Result<Option<LDAPSchema>, LdapSchemaError> {
    if let Some(root_dse) = query_root_dse(ldap).await? {
        let mut it = ldap_search(
            ldap,
            &root_dse.subschema_subentry,
            Scope::Base,
            "(objectClass=*)",
            vec![
                "ldapSyntaxes",
                "matchingRules",
                "matchingRuleUse",
                "attributeTypes",
                "objectClasses",
            ],
        )
        .await?;

        if let Some(entry) = it.next() {
            let ldap_syntaxes = entry
                .attrs
                .get("ldapSyntaxes")
                .unwrap()
                .iter()
                .map(|x| match ldap_syntax_parser().parse_recovery(x.as_str()) {
                    (Some(ldap_syntax), _) => Ok(ldap_syntax),
                    (_, errs) => Err(ChumskyError {
                        description: "ldap syntax".to_string(),
                        source: x.to_string(),
                        errors: errs,
                    }),
                })
                .collect::<Result<Vec<LDAPSyntax>, ChumskyError>>()?;
            let matching_rules = entry
                .attrs
                .get("matchingRules")
                .unwrap()
                .iter()
                .map(
                    |x| match matching_rule_parser().parse_recovery(x.as_str()) {
                        (Some(matching_rule), _) => Ok(matching_rule),
                        (_, errs) => Err(ChumskyError {
                            description: "matching rule".to_string(),
                            source: x.to_string(),
                            errors: errs,
                        }),
                    },
                )
                .collect::<Result<Vec<MatchingRule>, ChumskyError>>()?;
            let matching_rule_use = entry
                .attrs
                .get("matchingRuleUse")
                .unwrap()
                .iter()
                .map(
                    |x| match matching_rule_use_parser().parse_recovery(x.as_str()) {
                        (Some(matching_rule_use), _) => Ok(matching_rule_use),
                        (_, errs) => Err(ChumskyError {
                            description: "matching rule use".to_string(),
                            source: x.to_string(),
                            errors: errs,
                        }),
                    },
                )
                .collect::<Result<Vec<MatchingRuleUse>, ChumskyError>>()?;
            let attribute_types = entry
                .attrs
                .get("attributeTypes")
                .unwrap()
                .iter()
                .map(
                    |x| match attribute_type_parser().parse_recovery(x.as_str()) {
                        (Some(attribute_type), _) => Ok(attribute_type),
                        (_, errs) => Err(ChumskyError {
                            description: "attribute type".to_string(),
                            source: x.to_string(),
                            errors: errs,
                        }),
                    },
                )
                .collect::<Result<Vec<AttributeType>, ChumskyError>>()?;
            let object_classes = entry
                .attrs
                .get("objectClasses")
                .unwrap()
                .iter()
                .map(|x| match object_class_parser().parse_recovery(x.as_str()) {
                    (Some(object_class), _) => Ok(object_class),
                    (_, errs) => Err(ChumskyError {
                        description: "object class".to_string(),
                        source: x.to_string(),
                        errors: errs,
                    }),
                })
                .collect::<Result<Vec<ObjectClass>, ChumskyError>>()?;
            return Ok(Some(LDAPSchema {
                ldap_syntaxes,
                matching_rules,
                matching_rule_use,
                attribute_types,
                object_classes,
            }));
        }
    }
    Ok(None)
}

/// check if an [ldap3::LdapResult] is either a success or the success code returned by an operation using the [noop_control]
pub fn success_or_noop_success(
    ldap_result: ldap3::LdapResult,
) -> ldap3::result::Result<ldap3::LdapResult> {
    // 16654 is success in the presence of the noop control https://ldap.com/ldap-result-code-reference-other-server-side-result-codes/#rc-noOperation
    if ldap_result.rc == 0 || ldap_result.rc == 16654 {
        Ok(ldap_result)
    } else {
        Err(ldap3::LdapError::from(ldap_result))
    }
}

/// delete an LDAP entry recursively using ldap3
#[instrument(skip(ldap))]
pub async fn delete_recursive(
    ldap: &mut Ldap,
    dn: &str,
    controls: Vec<ldap3::controls::RawControl>,
) -> Result<(), LdapOperationError> {
    tracing::debug!("Deleting {} recursively", dn);
    let it = ldap_search(
        ldap,
        dn,
        Scope::Subtree,
        "(objectClass=*)",
        Vec::<String>::new(),
    )
    .await?;
    let mut entries = vec![];
    for entry in it {
        tracing::debug!("Found child entry to delete {}", entry.dn);
        entries.push(entry.dn);
    }
    entries.sort_by_key(|b| std::cmp::Reverse(b.len()));
    for dn in entries {
        tracing::debug!("Deleting child entry {}", dn);
        success_or_noop_success(ldap.with_controls(controls.to_owned()).delete(&dn).await?)?;
    }
    Ok(())
}

/// of the same modify operation because otherwise we might successfully apply the textual modifications
/// and then fail on the binary ones, leaving behind a half-modified object
pub fn mods_as_bin_mods<'a, T>(mods: T) -> Vec<ldap3::Mod<Vec<u8>>>
where
    T: IntoIterator<Item = &'a ldap3::Mod<String>>,
{
    let mut result: Vec<ldap3::Mod<Vec<u8>>> = vec![];
    for m in mods {
        match m {
            ldap3::Mod::Add(k, v) => {
                result.push(ldap3::Mod::Add(
                    k.as_bytes().to_vec(),
                    v.iter().map(|s| s.as_bytes().to_vec()).collect(),
                ));
            }
            ldap3::Mod::Delete(k, v) => {
                result.push(ldap3::Mod::Delete(
                    k.as_bytes().to_vec(),
                    v.iter().map(|s| s.as_bytes().to_vec()).collect(),
                ));
            }
            ldap3::Mod::Replace(k, v) => {
                result.push(ldap3::Mod::Replace(
                    k.as_bytes().to_vec(),
                    v.iter().map(|s| s.as_bytes().to_vec()).collect(),
                ));
            }
            ldap3::Mod::Increment(k, v) => {
                result.push(ldap3::Mod::Increment(
                    k.as_bytes().to_vec(),
                    v.as_bytes().to_vec(),
                ));
            }
        }
    }
    result
}

/// apply the LDAP operations on a given LDAP server.
///
/// The operations should not include the Base-DN in its internally stored DNs
/// It will be added automatically. This allows for easier generation of comparisons
/// between objects on two different LDAP servers with different base DNs.
#[instrument(skip(ldap, ldap_operations))]
pub async fn apply_ldap_operations(
    ldap: &mut Ldap,
    ldap_base_dn: &str,
    ldap_operations: &[LDAPOperation],
    controls: Vec<ldap3::controls::RawControl>,
) -> Result<(), LdapOperationError> {
    tracing::debug!(
        "The following operations use the LDAP controls: {:#?}",
        controls
    );
    for op in ldap_operations {
        match op {
            LDAPOperation::Add(LDAPEntry {
                dn,
                attrs,
                bin_attrs,
            }) => {
                let full_dn = format!("{},{}", dn, ldap_base_dn);
                tracing::debug!(
                    "Adding LDAP entry at {} with attributes\n{:#?}\nand binary attributes\n{:#?}",
                    &full_dn,
                    attrs,
                    bin_attrs
                );
                // we need to perform the add in one operation or we will run into problems with
                // objectclass requirements
                let mut combined_attrs: Vec<(Vec<u8>, HashSet<Vec<u8>>)> = bin_attrs
                    .iter()
                    .map(|(k, v)| {
                        (
                            k.to_owned().as_bytes().to_vec(),
                            v.iter().map(|s| s.to_owned()).collect::<HashSet<Vec<u8>>>(),
                        )
                    })
                    .collect();
                combined_attrs.extend(attrs.iter().map(|(k, v)| {
                    (
                        k.to_owned().as_bytes().to_vec(),
                        v.iter()
                            .map(|s| s.as_bytes().to_vec())
                            .collect::<HashSet<Vec<u8>>>(),
                    )
                }));
                ldap.with_controls(controls.to_owned())
                    .add(&full_dn, combined_attrs)
                    .await?
                    .success()?;
            }
            LDAPOperation::Delete { dn } => {
                let full_dn = format!("{},{}", dn, ldap_base_dn);
                tracing::debug!("Deleting LDAP entry at {}", &full_dn);
                delete_recursive(ldap, &full_dn, controls.to_owned()).await?;
            }
            LDAPOperation::Modify { dn, mods, bin_mods } => {
                let full_dn = format!("{},{}", dn, ldap_base_dn);
                tracing::debug!("Modifying LDAP entry at {} with modifications\n{:#?}\nand binary modifications\n{:#?}", &full_dn, mods, bin_mods);
                let mut combined_mods = bin_mods.to_owned();
                combined_mods.extend(mods_as_bin_mods(mods));
                ldap.with_controls(controls.to_owned())
                    .modify(&full_dn, combined_mods.to_vec())
                    .await?
                    .success()?;
            }
        }
    }

    Ok(())
}

/// helper function to search an LDAP server and generate [LDAPEntry] values
/// with the base DN removed to make them server-independent
#[instrument(skip(ldap, entries))]
pub async fn search_entries(
    ldap: &mut Ldap,
    base_dn: &str,
    search_base: &str,
    scope: ldap3::Scope,
    filter: &str,
    attrs: &[String],
    entries: &mut HashMap<String, LDAPEntry>,
) -> Result<(), LdapOperationError> {
    let it = ldap_search(
        ldap,
        &format!("{},{}", search_base, base_dn),
        scope,
        filter,
        attrs.to_owned(),
    )
    .await?;
    for entry in it {
        tracing::debug!("Found entry {}", entry.dn);
        if let Some(s) = entry.dn.strip_suffix(&format!(",{}", &base_dn)) {
            entries.insert(
                s.to_string(),
                LDAPEntry {
                    dn: s.to_string(),
                    attrs: entry.attrs,
                    bin_attrs: entry.bin_attrs,
                },
            );
        } else {
            tracing::error!(
                "Failed to remove base dn {} from entry DN {}",
                base_dn,
                entry.dn
            );
        }
    }
    Ok(())
}

/// generate an [ldap3::Mod] if there is a DN-valued attribute in the source
/// entry that needs its base DN translated to the destination base DN
#[instrument(skip(
    source_entry,
    source_ldap_schema,
    source_base_dn,
    destination_entry,
    destination_base_dn,
    ignore_object_classes,
))]
pub fn mod_value(
    attr_name: &str,
    source_entry: &LDAPEntry,
    source_ldap_schema: &LDAPSchema,
    source_base_dn: &str,
    destination_entry: Option<&LDAPEntry>,
    destination_base_dn: &str,
    ignore_object_classes: &[String],
) -> Option<ldap3::Mod<String>> {
    lazy_static! {
        static ref DN_SYNTAX_OID: OIDWithLength = OIDWithLength {
            oid: ObjectIdentifier::try_from("1.3.6.1.4.1.1466.115.121.1.12").unwrap(),
            length: None
        };
    }
    if let Some(values) = source_entry.attrs.get(attr_name) {
        let mut replacement_values = HashSet::from_iter(values.iter().cloned());
        if attr_name == "objectClass" {
            for io in ignore_object_classes {
                replacement_values.remove(io);
            }
        }
        let attr_type_syntax =
            source_ldap_schema.find_attribute_type_property(attr_name, |at| at.syntax.as_ref());
        tracing::trace!(
            "Attribute type syntax for altered attribute {}: {:#?}",
            attr_name,
            attr_type_syntax
        );
        if let Some(syntax) = attr_type_syntax {
            if DN_SYNTAX_OID.eq(syntax) {
                tracing::trace!(
                    "Replacing base DN {} with base DN {}",
                    source_base_dn,
                    destination_base_dn
                );
                replacement_values = replacement_values
                    .into_iter()
                    .map(|s| s.replace(source_base_dn, destination_base_dn))
                    .collect();
            }
        }
        if let Some(destination_entry) = destination_entry {
            if let Some(destination_values) = destination_entry.attrs.get(attr_name) {
                let mut replacement_values_sorted: Vec<String> =
                    replacement_values.iter().cloned().collect();
                replacement_values_sorted.sort();
                let mut destination_values: Vec<String> = destination_values.to_vec();
                destination_values.sort();
                tracing::trace!("Checking if replacement values and destination values are identical (case sensitive):\n{:#?}\n{:#?}", destination_values, replacement_values_sorted);
                if replacement_values_sorted == destination_values {
                    tracing::trace!("Skipping attribute {} because replacement values and destination values are identical (case sensitive)", attr_name);
                    return None;
                }
                let attr_type_equality = source_ldap_schema
                    .find_attribute_type_property(attr_name, |at| at.equality.as_ref());
                tracing::trace!(
                    "Attribute type equality for altered attribute {}: {:#?}",
                    attr_name,
                    attr_type_equality
                );
                if let Some(equality) = &attr_type_equality {
                    if equality.describes_case_insensitive_match() {
                        let mut lower_destination_values: Vec<String> = destination_values
                            .iter()
                            .map(|s| s.to_lowercase())
                            .collect();
                        lower_destination_values.sort();
                        let mut lower_replacement_values: Vec<String> = replacement_values
                            .iter()
                            .map(|s| s.to_lowercase())
                            .collect();
                        lower_replacement_values.sort();
                        tracing::trace!("Checking if replacement values and destination values are identical (case insensitive):\n{:#?}\n{:#?}", lower_destination_values, lower_replacement_values);
                        if lower_destination_values == lower_replacement_values {
                            tracing::trace!("Skipping attribute {} because replacement values and destination values are identical (case insensitive)", attr_name);
                            return None;
                        }
                    }
                }
            }
        }
        Some(ldap3::Mod::Replace(
            attr_name.to_string(),
            replacement_values,
        ))
    } else {
        Some(ldap3::Mod::Delete(attr_name.to_string(), HashSet::new()))
    }
}

/// diff two sets of LDAPEntries which had their base DNs removed
/// and generates LDAP operations (add, update, delete) to apply to
/// the destination to make it identical to the source
#[allow(clippy::too_many_arguments)]
#[instrument(skip(source_ldap_schema))]
pub fn diff_entries(
    source_entries: &HashMap<String, LDAPEntry>,
    destination_entries: &HashMap<String, LDAPEntry>,
    source_base_dn: &str,
    destination_base_dn: &str,
    ignore_object_classes: &[String],
    ignore_attributes: &[String],
    source_ldap_schema: &LDAPSchema,
    add: bool,
    update: bool,
    delete: bool,
) -> Vec<LDAPOperation> {
    lazy_static! {
        static ref DN_SYNTAX_OID: OIDWithLength = OIDWithLength {
            oid: ObjectIdentifier::try_from("1.3.6.1.4.1.1466.115.121.1.12").unwrap(),
            length: None
        };
    }
    let diff = Diff::diff(source_entries, destination_entries);
    tracing::trace!("Diff:\n{:#?}", diff);
    let mut ldap_operations: Vec<LDAPOperation> = vec![];
    for (altered_dn, change) in diff.altered {
        tracing::trace!("Processing altered DN {}", altered_dn);
        let source_entry: Option<&LDAPEntry> = source_entries.get(&altered_dn);
        let destination_entry: Option<&LDAPEntry> = destination_entries.get(&altered_dn);
        if let Some(source_entry) = source_entry {
            let mut ldap_mods: Vec<ldap3::Mod<String>> = vec![];
            let mut ldap_bin_mods: Vec<ldap3::Mod<Vec<u8>>> = vec![];
            for (attr_name, attr_value_changes) in &change.attrs.altered {
                if ignore_attributes.contains(attr_name) {
                    continue;
                }
                for attr_value_change in &attr_value_changes.0 {
                    match attr_value_change {
                        VecDiffType::Removed { .. }
                        | VecDiffType::Inserted { .. }
                        | VecDiffType::Altered { .. } => {
                            let m = mod_value(
                                attr_name,
                                source_entry,
                                source_ldap_schema,
                                source_base_dn,
                                destination_entry,
                                destination_base_dn,
                                ignore_object_classes,
                            );
                            if let Some(m) = m {
                                if !ldap_mods.contains(&m) {
                                    ldap_mods.push(m);
                                }
                            }
                        }
                    }
                }
            }
            for attr_name in &change.attrs.removed {
                if ignore_attributes.contains(attr_name) {
                    continue;
                }
                let mut replacement_values =
                    HashSet::from_iter(source_entry.attrs[attr_name].iter().cloned());
                if attr_name == "objectClass" {
                    for io in ignore_object_classes {
                        replacement_values.remove(io);
                    }
                }
                let attr_type_syntax = source_ldap_schema
                    .find_attribute_type_property(attr_name, |at| at.syntax.as_ref());
                tracing::trace!(
                    "Attribute type syntax for deleted attribute {}: {:#?}",
                    attr_name,
                    attr_type_syntax
                );
                if let Some(syntax) = attr_type_syntax {
                    if DN_SYNTAX_OID.eq(syntax) {
                        tracing::trace!(
                            "Replacing base DN {} with base DN {}",
                            source_base_dn,
                            destination_base_dn
                        );
                        replacement_values = replacement_values
                            .into_iter()
                            .map(|s| s.replace(source_base_dn, destination_base_dn))
                            .collect();
                    }
                }
                ldap_mods.push(ldap3::Mod::Add(attr_name.to_string(), replacement_values));
            }
            for (attr_name, attr_value_changes) in &change.bin_attrs.altered {
                if ignore_attributes.contains(attr_name) {
                    continue;
                }
                for attr_value_change in &attr_value_changes.0 {
                    match attr_value_change {
                        VecDiffType::Removed { .. }
                        | VecDiffType::Inserted { .. }
                        | VecDiffType::Altered { .. } => {
                            if let Some(values) = source_entry.bin_attrs.get(attr_name) {
                                let replace_mod = ldap3::Mod::Replace(
                                    attr_name.as_bytes().to_vec(),
                                    HashSet::from_iter(values.iter().cloned()),
                                );
                                if !ldap_bin_mods.contains(&replace_mod) {
                                    ldap_bin_mods.push(replace_mod)
                                }
                            } else {
                                ldap_bin_mods.push(ldap3::Mod::Delete(
                                    attr_name.as_bytes().to_vec(),
                                    HashSet::new(),
                                ));
                            }
                        }
                    }
                }
            }
            for attr_name in &change.bin_attrs.removed {
                if ignore_attributes.contains(attr_name) {
                    continue;
                }
                ldap_bin_mods.push(ldap3::Mod::Add(
                    attr_name.as_bytes().to_vec(),
                    HashSet::from_iter(source_entry.bin_attrs[attr_name].iter().cloned()),
                ));
            }
            if update && !(ldap_mods.is_empty() && ldap_bin_mods.is_empty()) {
                ldap_operations.push(LDAPOperation::Modify {
                    dn: source_entry.dn.clone(),
                    mods: ldap_mods,
                    bin_mods: ldap_bin_mods,
                });
            }
        } else if delete {
            ldap_operations.push(LDAPOperation::Delete {
                dn: altered_dn.clone(),
            });
        }
    }
    for removed_dn in diff.removed {
        if add {
            let mut new_entry = source_entries[&removed_dn].clone();
            for ia in ignore_attributes {
                new_entry.attrs.remove(ia);
                new_entry.bin_attrs.remove(ia);
            }
            if let Some((k, v)) = new_entry.attrs.remove_entry("objectClass") {
                let ioc = &ignore_object_classes;
                let new_v = v.into_iter().filter(|x| !ioc.contains(x)).collect();
                new_entry.attrs.insert(k, new_v);
            }
            for (attr_name, attr_values) in new_entry.attrs.iter_mut() {
                let attr_type_syntax = source_ldap_schema
                    .find_attribute_type_property(attr_name, |at| at.syntax.as_ref());
                tracing::trace!(
                    "Attribute type syntax for attribute {} in deleted entry {}: {:#?}",
                    attr_name,
                    removed_dn,
                    attr_type_syntax
                );
                if let Some(syntax) = attr_type_syntax {
                    if DN_SYNTAX_OID.eq(syntax) {
                        tracing::trace!(
                            "Replacing base DN {} with base DN {}",
                            source_base_dn,
                            destination_base_dn
                        );
                        for s in attr_values.iter_mut() {
                            *s = s.replace(source_base_dn, destination_base_dn);
                        }
                    }
                }
            }
            ldap_operations.push(LDAPOperation::Add(new_entry));
        }
    }

    ldap_operations.sort_by(|a, b| {
        a.operation_apply_cmp(b)
            .unwrap_or(std::cmp::Ordering::Equal)
    });

    ldap_operations
}