Merge pull request #1191 from slingamn/moderation.3

enhancements to moderation (#1134, #1135)

docs/MANUAL.md

@@ -35,6 +35,7 @@ _Copyright © Daniel Oaks <daniel@danieloaks.net>, Shivaram Lingamneni <slingamn
     - Multiclient ("Bouncer")
     - History
     - IP cloaking
+    - Moderation
 - Frequently Asked Questions
 - IRC over TLS
 - Modes
@@ -362,6 +363,26 @@ Oragono supports cloaking, which is enabled by default (via the `server.ip-cloak
 
 Setting `server.ip-cloaking.num-bits` to 0 gives users cloaks that don't depend on their IP address information at all, which is an option for deployments where privacy is a more pressing concern than abuse. Holders of registered accounts can also use the vhost system (for details, `/msg HostServ HELP`.)
 
+
+## Moderation
+
+Oragono's multiclient and always-on features mean that moderation (at the server operator level) requires different techniques than a traditional IRC network. Server operators have three principal tools for moderation:
+
+1. `/NICKSERV SUSPEND`, which disables a user account and disconnects all associated clients
+2. `/DLINE ANDKILL`, which bans an IP or CIDR and disconnects clients
+3. `/DEFCON`, which can impose emergency restrictions on user activity in response to attacks
+
+See the `/HELP` (or `/HELPOP`) entries for these commands for more information, but here's a rough workflow for mitigating spam or other attacks:
+
+1. Subscribe to the `a` snomask to monitor for abusive registration attempts (this is set automatically in the default operator config, but can be added manually with `/mode mynick +s u`)
+2. Given abusive traffic from a nickname, identify whether they are using an account (this should be displayed in `/WHOIS` output)
+3. If they are using an account, suspend the account with `/NICKSERV SUSPEND`, which will disconnect them
+4. If they are not using an account, or if they're spamming new registrations from an IP, determine the IP (either from `/WHOIS` or from account registration notices) and temporarily `/DLINE` their IP
+5. When facing a flood of abusive registrations that cannot be stemmed with `/DLINE`, use `/DEFCON 4` to temporarily restrict registrations. (At `/DEFCON 2`, all new connections to the server will require SASL, but this will likely be disruptive to legitimate users as well.)
+
+For channel operators, as opposed to server operators, most traditional moderation tools should be effective. In particular, bans on cloaked hostnames (e.g., `/mode #chan +b *!*@98rgwnst3dahu.my.network`) should work as expected. With `force-nick-equals-account` enabled, channel operators can also ban nicknames (with `/mode #chan +b nick`, which Oragono automatically expands to `/mode #chan +b nick!*@*` as a way of banning an account.)
+
+
 -------------------------------------------------------------------------------------------
 
 

irc/accounts.go

@@ -1223,6 +1223,69 @@ func (am *AccountManager) loadRawAccount(tx *buntdb.Tx, casefoldedAccount string
 	return
 }
 
+func (am *AccountManager) Suspend(accountName string) (err error) {
+	account, err := CasefoldName(accountName)
+	if err != nil {
+		return errAccountDoesNotExist
+	}
+
+	existsKey := fmt.Sprintf(keyAccountExists, account)
+	verifiedKey := fmt.Sprintf(keyAccountVerified, account)
+	err = am.server.store.Update(func(tx *buntdb.Tx) error {
+		_, err := tx.Get(existsKey)
+		if err != nil {
+			return errAccountDoesNotExist
+		}
+		_, err = tx.Delete(verifiedKey)
+		return err
+	})
+
+	if err == errAccountDoesNotExist {
+		return err
+	} else if err != nil {
+		am.server.logger.Error("internal", "couldn't persist suspension", account, err.Error())
+	} // keep going
+
+	am.Lock()
+	clients := am.accountToClients[account]
+	delete(am.accountToClients, account)
+	am.Unlock()
+
+	am.killClients(clients)
+	return nil
+}
+
+func (am *AccountManager) killClients(clients []*Client) {
+	for _, client := range clients {
+		client.Logout()
+		client.Quit(client.t("You are no longer authorized to be on this server"), nil)
+		client.destroy(nil)
+	}
+}
+
+func (am *AccountManager) Unsuspend(account string) (err error) {
+	cfaccount, err := CasefoldName(account)
+	if err != nil {
+		return errAccountDoesNotExist
+	}
+
+	existsKey := fmt.Sprintf(keyAccountExists, cfaccount)
+	verifiedKey := fmt.Sprintf(keyAccountVerified, cfaccount)
+	err = am.server.store.Update(func(tx *buntdb.Tx) error {
+		_, err := tx.Get(existsKey)
+		if err != nil {
+			return errAccountDoesNotExist
+		}
+		tx.Set(verifiedKey, "1", nil)
+		return nil
+	})
+
+	if err != nil {
+		return errAccountDoesNotExist
+	}
+	return nil
+}
+
 func (am *AccountManager) Unregister(account string, erase bool) error {
 	config := am.server.Config()
 	casefoldedAccount, err := CasefoldName(account)
@@ -1248,6 +1311,9 @@ func (am *AccountManager) Unregister(account string, erase bool) error {
 	modesKey := fmt.Sprintf(keyAccountModes, casefoldedAccount)
 
 	var clients []*Client
+	defer func() {
+		am.killClients(clients)
+	}()
 
 	var registeredChannels []string
 	// on our way out, unregister all the account's channels and delete them from the db
@@ -1341,12 +1407,6 @@ func (am *AccountManager) Unregister(account string, erase bool) error {
 		additionalSkel, _ := Skeleton(nick)
 		delete(am.skeletonToAccount, additionalSkel)
 	}
-	for _, client := range clients {
-		client.Logout()
-		client.Quit(client.t("You are no longer authorized to be on this server"), nil)
-		// destroy acquires a semaphore so we can't call it while holding a lock
-		go client.destroy(nil)
-	}
 
 	if err != nil && !erase {
 		return errAccountDoesNotExist

irc/client.go

@@ -59,7 +59,6 @@ type Client struct {
 	channels           ChannelSet
 	ctime              time.Time
 	destroyed          bool
-	exitedSnomaskSent  bool
 	modes              modes.ModeSet
 	hostname           string
 	invitedTo          StringSet
@@ -1281,7 +1280,6 @@ func (client *Client) destroy(session *Session) {
 	if saveLastSeen {
 		client.dirtyBits |= IncludeLastSeen
 	}
-	exitedSnomaskSent := client.exitedSnomaskSent
 
 	autoAway := false
 	var awayMessage string
@@ -1423,7 +1421,7 @@ func (client *Client) destroy(session *Session) {
 		friend.sendFromClientInternal(false, splitQuitMessage.Time, splitQuitMessage.Msgid, details.nickMask, details.accountName, nil, "QUIT", quitMessage)
 	}
 
-	if !exitedSnomaskSent && registered {
+	if registered {
 		client.server.snomasks.Send(sno.LocalQuits, fmt.Sprintf(ircfmt.Unescape("%s$r exited the network"), details.nick))
 	}
 }

irc/getters.go

@@ -201,12 +201,6 @@ func (client *Client) SetAway(away bool, awayMessage string) (changed bool) {
 	return
 }
 
-func (client *Client) SetExitedSnomaskSent() {
-	client.stateMutex.Lock()
-	client.exitedSnomaskSent = true
-	client.stateMutex.Unlock()
-}
-
 func (client *Client) AlwaysOn() (alwaysOn bool) {
 	client.stateMutex.Lock()
 	alwaysOn = client.alwaysOn

irc/handlers.go

@@ -83,7 +83,7 @@ func sendSuccessfulRegResponse(client *Client, rb *ResponseBuffer, forNS bool) {
 	} else {
 		rb.Add(nil, client.server.name, RPL_REG_SUCCESS, details.nick, details.accountName, client.t("Account created"))
 	}
-	client.server.snomasks.Send(sno.LocalAccounts, fmt.Sprintf(ircfmt.Unescape("Client $c[grey][$r%s$c[grey]] registered account $c[grey][$r%s$c[grey]]"), details.nickMask, details.accountName))
+	client.server.snomasks.Send(sno.LocalAccounts, fmt.Sprintf(ircfmt.Unescape("Client $c[grey][$r%s$c[grey]] registered account $c[grey][$r%s$c[grey]] from IP %s"), details.nickMask, details.accountName, rb.session.IP().String()))
 	sendSuccessfulAccountAuth(client, rb, forNS, false)
 }
 
@@ -867,7 +867,7 @@ func dlineHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *Res
 		return false
 	}
 
-	if !dlineMyself && hostNet.Contains(client.IP()) {
+	if !dlineMyself && hostNet.Contains(rb.session.IP()) {
 		rb.Add(nil, server.name, ERR_UNKNOWNERROR, client.nick, msg.Command, client.t("This ban matches you. To DLINE yourself, you must use the command:  /DLINE MYSELF <arguments>"))
 		return false
 	}
@@ -906,24 +906,30 @@ func dlineHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *Res
 
 	var killClient bool
 	if andKill {
-		var clientsToKill []*Client
+		var sessionsToKill []*Session
 		var killedClientNicks []string
 
 		for _, mcl := range server.clients.AllClients() {
-			if hostNet.Contains(mcl.IP()) {
-				clientsToKill = append(clientsToKill, mcl)
-				killedClientNicks = append(killedClientNicks, mcl.nick)
+			nickKilled := false
+			for _, session := range mcl.Sessions() {
+				if hostNet.Contains(session.IP()) {
+					sessionsToKill = append(sessionsToKill, session)
+					if !nickKilled {
+						killedClientNicks = append(killedClientNicks, mcl.Nick())
+						nickKilled = true
+					}
+				}
 			}
 		}
 
-		for _, mcl := range clientsToKill {
-			mcl.SetExitedSnomaskSent()
-			mcl.Quit(fmt.Sprintf(mcl.t("You have been banned from this server (%s)"), reason), nil)
-			if mcl == client {
+		for _, session := range sessionsToKill {
+			mcl := session.client
+			mcl.Quit(fmt.Sprintf(mcl.t("You have been banned from this server (%s)"), reason), session)
+			if session == rb.session {
 				killClient = true
 			} else {
 				// if mcl == client, we kill them below
-				mcl.destroy(nil)
+				mcl.destroy(session)
 			}
 		}
 
@@ -1296,14 +1302,15 @@ func killHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *Resp
 
 	target := server.clients.Get(nickname)
 	if target == nil {
-		rb.Add(nil, client.server.name, ERR_NOSUCHNICK, client.nick, utils.SafeErrorParam(nickname), client.t("No such nick"))
+		rb.Add(nil, client.server.name, ERR_NOSUCHNICK, client.Nick(), utils.SafeErrorParam(nickname), client.t("No such nick"))
 		return false
+	} else if target.AlwaysOn() {
+		rb.Add(nil, client.server.name, ERR_UNKNOWNERROR, client.Nick(), "KILL", fmt.Sprintf(client.t("Client %s is always-on and cannot be fully removed by /KILL; consider /NS SUSPEND instead"), target.Nick()))
 	}
 
 	quitMsg := fmt.Sprintf("Killed (%s (%s))", client.nick, comment)
 
 	server.snomasks.Send(sno.LocalKills, fmt.Sprintf(ircfmt.Unescape("%s$r was killed by %s $c[grey][$r%s$c[grey]]"), target.nick, client.nick, comment))
-	target.SetExitedSnomaskSent()
 
 	target.Quit(quitMsg, nil)
 	target.destroy(nil)
@@ -1435,7 +1442,6 @@ func klineHandler(server *Server, client *Client, msg ircmsg.IrcMessage, rb *Res
 		}
 
 		for _, mcl := range clientsToKill {
-			mcl.SetExitedSnomaskSent()
 			mcl.Quit(fmt.Sprintf(mcl.t("You have been banned from this server (%s)"), reason), nil)
 			if mcl == client {
 				killClient = true

irc/nickserv.go

@@ -316,6 +316,24 @@ example with $bCERT ADD <account> <fingerprint>$b.`,
 			enabled:   servCmdRequiresAuthEnabled,
 			minParams: 1,
 		},
+		"suspend": {
+			handler: nsSuspendHandler,
+			help: `Syntax: $bSUSPEND <nickname>$b
+
+SUSPEND disables an account and disconnects the associated clients.`,
+			helpShort: `$bSUSPEND$b disables an account and disconnects the clients`,
+			minParams: 1,
+			capabs:    []string{"accreg"},
+		},
+		"unsuspend": {
+			handler: nsUnsuspendHandler,
+			help: `Syntax: $bUNSUSPEND <nickname>$b
+
+UNSUSPEND reverses a previous SUSPEND, restoring access to the account.`,
+			helpShort: `$bUNSUSPEND$b restores access to a suspended account`,
+			minParams: 1,
+			capabs:    []string{"accreg"},
+		},
 	}
 )
 
@@ -1177,3 +1195,27 @@ func nsCertHandler(server *Server, client *Client, command string, params []stri
 		nsNotice(rb, client.t("An error occurred"))
 	}
 }
+
+func nsSuspendHandler(server *Server, client *Client, command string, params []string, rb *ResponseBuffer) {
+	err := server.accounts.Suspend(params[0])
+	switch err {
+	case nil:
+		nsNotice(rb, fmt.Sprintf(client.t("Successfully suspended account %s"), params[0]))
+	case errAccountDoesNotExist:
+		nsNotice(rb, client.t("No such account"))
+	default:
+		nsNotice(rb, client.t("An error occurred"))
+	}
+}
+
+func nsUnsuspendHandler(server *Server, client *Client, command string, params []string, rb *ResponseBuffer) {
+	err := server.accounts.Unsuspend(params[0])
+	switch err {
+	case nil:
+		nsNotice(rb, fmt.Sprintf(client.t("Successfully un-suspended account %s"), params[0]))
+	case errAccountDoesNotExist:
+		nsNotice(rb, client.t("No such account"))
+	default:
+		nsNotice(rb, client.t("An error occurred"))
+	}
+}