ergo/irc/nickserv.go

// Copyright (c) 2017 Daniel Oaks <daniel@danieloaks.net>
// released under the MIT license

package irc

import (
	"encoding/json"
	"fmt"
	"strconv"
	"strings"
	"time"

	"github.com/goshuirc/irc-go/ircfmt"
	"github.com/oragono/oragono/irc/passwd"
	"github.com/oragono/oragono/irc/sno"
	"github.com/tidwall/buntdb"
)

const nickservHelp = `NickServ lets you register and log into a user account.

To register an account:
	/NS REGISTER username [password]
Leave out [password] if you're registering using your client certificate fingerprint.

To login to an account:
	/NS IDENTIFY [username password]
Leave out [username password] to use your client certificate fingerprint. Otherwise,
the given username and password will be used.`

// extractParam extracts a parameter from the given string, returning the param and the rest of the string.
func extractParam(line string) (string, string) {
	rawParams := strings.SplitN(strings.TrimSpace(line), " ", 2)
	param0 := rawParams[0]
	var param1 string
	if 1 < len(rawParams) {
		param1 = strings.TrimSpace(rawParams[1])
	}
	return param0, param1
}

// nickservNoticeHandler handles NOTICEs that NickServ receives.
func (server *Server) nickservNoticeHandler(client *Client, message string) {
	// do nothing
}

// nickservPrivmsgHandler handles PRIVMSGs that NickServ receives.
func (server *Server) nickservPrivmsgHandler(client *Client, message string) {
	command, params := extractParam(message)
	command = strings.ToLower(command)

	if command == "help" {
		for _, line := range strings.Split(nickservHelp, "\n") {
			client.Notice(line)
		}
	} else if command == "register" {
		// get params
		username, passphrase := extractParam(params)

		// fail out if we need to
		if username == "" {
			client.Notice(client.t("No username supplied"))
			return
		}

		server.nickservRegisterHandler(client, username, passphrase)
	} else if command == "identify" {
		// get params
		username, passphrase := extractParam(params)

		server.nickservIdentifyHandler(client, username, passphrase)
	} else {
		client.Notice(client.t("Command not recognised. To see the available commands, run /NS HELP"))
	}
}

func (server *Server) nickservRegisterHandler(client *Client, username, passphrase string) {
	certfp := client.certfp
	if passphrase == "" && certfp == "" {
		client.Notice(client.t("You need to either supply a passphrase or be connected via TLS with a client cert"))
		return
	}

	if !server.accountRegistration.Enabled {
		client.Notice(client.t("Account registration has been disabled"))
		return
	}

	if client.LoggedIntoAccount() {
		if server.accountRegistration.AllowMultiplePerConnection {
			client.LogoutOfAccount()
		} else {
			client.Notice(client.t("You're already logged into an account"))
			return
		}
	}

	// get and sanitise account name
	account := strings.TrimSpace(username)
	casefoldedAccount, err := CasefoldName(account)
	// probably don't need explicit check for "*" here... but let's do it anyway just to make sure
	if err != nil || username == "*" {
		client.Notice(client.t("Account name is not valid"))
		return
	}

	// check whether account exists
	// do it all in one write tx to prevent races
	err = server.store.Update(func(tx *buntdb.Tx) error {
		accountKey := fmt.Sprintf(keyAccountExists, casefoldedAccount)

		_, err := tx.Get(accountKey)
		if err != buntdb.ErrNotFound {
			//TODO(dan): if account verified key doesn't exist account is not verified, calc the maximum time without verification and expire and continue if need be
			client.Notice(client.t("Account already exists"))
			return errAccountCreation
		}

		registeredTimeKey := fmt.Sprintf(keyAccountRegTime, casefoldedAccount)

		tx.Set(accountKey, "1", nil)
		tx.Set(fmt.Sprintf(keyAccountName, casefoldedAccount), account, nil)
		tx.Set(registeredTimeKey, strconv.FormatInt(time.Now().Unix(), 10), nil)
		return nil
	})

	// account could not be created and relevant numerics have been dispatched, abort
	if err != nil {
		if err != errAccountCreation {
			client.Notice(client.t("Account registration failed"))
		}
		return
	}

	// store details
	err = server.store.Update(func(tx *buntdb.Tx) error {
		// certfp special lookup key
		if passphrase == "" {
			assembledKeyCertToAccount := fmt.Sprintf(keyCertToAccount, client.certfp)

			// make sure certfp doesn't already exist because that'd be silly
			_, err := tx.Get(assembledKeyCertToAccount)
			if err != buntdb.ErrNotFound {
				return errCertfpAlreadyExists
			}

			tx.Set(assembledKeyCertToAccount, casefoldedAccount, nil)
		}

		// make creds
		var creds AccountCredentials

		// always set passphrase salt
		creds.PassphraseSalt, err = passwd.NewSalt()
		if err != nil {
			return fmt.Errorf("Could not create passphrase salt: %s", err.Error())
		}

		if passphrase == "" {
			creds.Certificate = client.certfp
		} else {
			creds.PassphraseHash, err = server.passwords.GenerateFromPassword(creds.PassphraseSalt, passphrase)
			if err != nil {
				return fmt.Errorf("Could not hash password: %s", err)
			}
		}
		credText, err := json.Marshal(creds)
		if err != nil {
			return fmt.Errorf("Could not marshal creds: %s", err)
		}
		tx.Set(fmt.Sprintf(keyAccountCredentials, account), string(credText), nil)

		return nil
	})

	// details could not be stored and relevant numerics have been dispatched, abort
	if err != nil {
		errMsg := "Could not register"
		if err == errCertfpAlreadyExists {
			errMsg = "An account already exists for your certificate fingerprint"
		}
		client.Notice(errMsg)
		removeFailedAccRegisterData(server.store, casefoldedAccount)
		return
	}

	err = server.store.Update(func(tx *buntdb.Tx) error {
		tx.Set(fmt.Sprintf(keyAccountVerified, casefoldedAccount), "1", nil)

		// load acct info inside store tx
		account := ClientAccount{
			Name:         username,
			RegisteredAt: time.Now(),
			Clients:      []*Client{client},
		}
		//TODO(dan): Consider creating ircd-wide account adding/removing/affecting lock for protecting access to these sorts of variables
		server.accounts[casefoldedAccount] = &account
		client.account = &account

		client.Notice(client.t("Account created"))
		client.Send(nil, server.name, RPL_LOGGEDIN, client.nick, client.nickMaskString, account.Name, fmt.Sprintf(client.t("You are now logged in as %s"), account.Name))
		client.Send(nil, server.name, RPL_SASLSUCCESS, client.nick, client.t("Authentication successful"))
		server.snomasks.Send(sno.LocalAccounts, fmt.Sprintf(ircfmt.Unescape("Account registered $c[grey][$r%s$c[grey]] by $c[grey][$r%s$c[grey]]"), account.Name, client.nickMaskString))
		return nil
	})
	if err != nil {
		client.Notice(client.t("Account registration failed"))
		removeFailedAccRegisterData(server.store, casefoldedAccount)
		return
	}
}

func (server *Server) nickservIdentifyHandler(client *Client, username, passphrase string) {
	// fail out if we need to
	if !server.accountAuthenticationEnabled {
		client.Notice(client.t("Login has been disabled"))
		return
	}

	// try passphrase
	if username != "" && passphrase != "" {
		// keep it the same as in the ACC CREATE stage
		accountKey, err := CasefoldName(username)
		if err != nil {
			client.Notice(client.t("Could not login with your username/password"))
			return
		}

		// load and check acct data all in one update to prevent races.
		// as noted elsewhere, change to proper locking for Account type later probably
		var accountName string
		err = server.store.Update(func(tx *buntdb.Tx) error {
			// confirm account is verified
			_, err = tx.Get(fmt.Sprintf(keyAccountVerified, accountKey))
			if err != nil {
				return errSaslFail
			}

			creds, err := loadAccountCredentials(tx, accountKey)
			if err != nil {
				return err
			}

			// ensure creds are valid
			if len(creds.PassphraseHash) < 1 || len(creds.PassphraseSalt) < 1 || len(passphrase) < 1 {
				return errSaslFail
			}
			err = server.passwords.CompareHashAndPassword(creds.PassphraseHash, creds.PassphraseSalt, passphrase)

			// succeeded, load account info if necessary
			account, exists := server.accounts[accountKey]
			if !exists {
				account = loadAccount(server, tx, accountKey)
			}

			client.LoginToAccount(account)
			accountName = account.Name

			return err
		})

		if err == nil {
			client.Notice(fmt.Sprintf(client.t("You're now logged in as %s"), accountName))
			return
		}
	}

	// try certfp
	certfp := client.certfp
	if certfp != "" {
		var accountName string
		err := server.store.Update(func(tx *buntdb.Tx) error {
			// certfp lookup key
			accountKey, err := tx.Get(fmt.Sprintf(keyCertToAccount, certfp))
			if err != nil {
				return errSaslFail
			}

			// confirm account exists
			_, err = tx.Get(fmt.Sprintf(keyAccountExists, accountKey))
			if err != nil {
				return errSaslFail
			}

			// confirm account is verified
			_, err = tx.Get(fmt.Sprintf(keyAccountVerified, accountKey))
			if err != nil {
				return errSaslFail
			}

			// confirm the certfp in that account's credentials
			creds, err := loadAccountCredentials(tx, accountKey)
			if err != nil || creds.Certificate != client.certfp {
				return errSaslFail
			}

			// succeeded, load account info if necessary
			account, exists := server.accounts[accountKey]
			if !exists {
				account = loadAccount(server, tx, accountKey)
			}

			client.LoginToAccount(account)
			accountName = account.Name

			return nil
		})

		if err == nil {
			client.Notice(fmt.Sprintf(client.t("You're now logged in as %s"), accountName))
			return
		}
	}

	client.Notice(client.t("Could not login with your TLS certificate or supplied username/password"))
}