GitHub/ergo
3
0
Fork 0
mirror of https://github.com/ergochat/ergo.git synced 2024-11-13 07:29:30 +01:00
Code Issues Projects Releases Wiki Activity

scripting API for IP bans

Browse Source 
See discussion on #68.
This commit is contained in:
Shivaram Lingamneni 2020-09-14 04:28:12 -04:00
parent a742ef9639
commit 1a98a37a75
10 changed files with 271 additions and 105 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
conventional.yaml
View File

@ -243,6 +243,22 @@ server:
# max-concurrent-connections: 128
# max-connections-per-window: 1024
# pluggable IP ban mechanism, via subprocess invocation
# this can be used to check new connections against a DNSBL, for example
# see the manual for details on how to write an IP ban checking script
ip-check-script:
enabled: false
command: "/usr/local/bin/check-ip-ban"
# constant list of args to pass to the command; the actual query
# and result are transmitted over stdin/stdout:
args: []
# timeout for process execution, after which we send a SIGTERM:
timeout: 9s
# how long after the SIGTERM before we follow up with a SIGKILL:
kill-timeout: 1s
# how many scripts are allowed to run at once? 0 for no limit:
max-concurrency: 64
# IP cloaking hides users' IP addresses from other users and from channel admins
# (but not from server admins), while still allowing channel admins to ban
# offending IP addresses or networks. In place of hostnames derived from reverse
@ -483,6 +499,8 @@ accounts:
timeout: 9s
# how long after the SIGTERM before we follow up with a SIGKILL:
kill-timeout: 1s
# how many scripts are allowed to run at once? 0 for no limit:
max-concurrency: 64
# channel options
channels:

18
default.yaml
View File

@ -270,6 +270,22 @@ server:
# max-concurrent-connections: 128
# max-connections-per-window: 1024
# pluggable IP ban mechanism, via subprocess invocation
# this can be used to check new connections against a DNSBL, for example
# see the manual for details on how to write an IP ban checking script
ip-check-script:
enabled: false
command: "/usr/local/bin/check-ip-ban"
# constant list of args to pass to the command; the actual query
# and result are transmitted over stdin/stdout:
args: []
# timeout for process execution, after which we send a SIGTERM:
timeout: 9s
# how long after the SIGTERM before we follow up with a SIGKILL:
kill-timeout: 1s
# how many scripts are allowed to run at once? 0 for no limit:
max-concurrency: 64
# IP cloaking hides users' IP addresses from other users and from channel admins
# (but not from server admins), while still allowing channel admins to ban
# offending IP addresses or networks. In place of hostnames derived from reverse
@ -511,6 +527,8 @@ accounts:
timeout: 9s
# how long after the SIGTERM before we follow up with a SIGKILL:
kill-timeout: 1s
# how many scripts are allowed to run at once? 0 for no limit:
max-concurrency: 64
# channel options
channels:

4
irc/accounts.go
View File

@ -1095,7 +1095,7 @@ func (am *AccountManager) AuthenticateByPassphrase(client *Client, accountName s
config := am.server.Config()
if config.Accounts.AuthScript.Enabled {
var output AuthScriptOutput
output, err = CheckAuthScript(config.Accounts.AuthScript,
output, err = CheckAuthScript(am.server.semaphores.AuthScript, config.Accounts.AuthScript.ScriptConfig,
AuthScriptInput{AccountName: accountName, Passphrase: passphrase, IP: client.IP().String()})
if err != nil {
am.server.logger.Error("internal", "failed shell auth invocation", err.Error())
@ -1494,7 +1494,7 @@ func (am *AccountManager) AuthenticateByCertFP(client *Client, certfp, authzid s
config := am.server.Config()
if config.Accounts.AuthScript.Enabled {
var output AuthScriptOutput
output, err = CheckAuthScript(config.Accounts.AuthScript,
output, err = CheckAuthScript(am.server.semaphores.AuthScript, config.Accounts.AuthScript.ScriptConfig,
AuthScriptInput{Certfp: certfp, IP: client.IP().String()})
if err != nil {
am.server.logger.Error("internal", "failed shell auth invocation", err.Error())

125
irc/authscript.go
View File

@ -4,13 +4,11 @@
package irc
import (
"bufio"
"encoding/json"
"fmt"
"io"
"os/exec"
"syscall"
"time"
"net"
"github.com/oragono/oragono/irc/utils"
)
// JSON-serializable input and output types for the script
@ -27,84 +25,77 @@ type AuthScriptOutput struct {
Error string `json:"error"`
}
// internal tupling of output and error for passing over a channel
type authScriptResponse struct {
output AuthScriptOutput
err error
}
func CheckAuthScript(sem utils.Semaphore, config ScriptConfig, input AuthScriptInput) (output AuthScriptOutput, err error) {
if sem != nil {
sem.Acquire()
defer sem.Release()
}
func CheckAuthScript(config AuthScriptConfig, input AuthScriptInput) (output AuthScriptOutput, err error) {
inputBytes, err := json.Marshal(input)
if err != nil {
return
}
cmd := exec.Command(config.Command, config.Args...)
stdin, err := cmd.StdinPipe()
outBytes, err := RunScript(config.Command, config.Args, inputBytes, config.Timeout, config.KillTimeout)
if err != nil {
return
}
stdout, err := cmd.StdoutPipe()
err = json.Unmarshal(outBytes, &output)
if err != nil {
return
}
channel := make(chan authScriptResponse, 1)
err = cmd.Start()
if err != nil {
return
if output.Error != "" {
err = fmt.Errorf("Authentication process reported error: %s", output.Error)
}
stdin.Write(inputBytes)
stdin.Write([]byte{'\n'})
// lots of potential race conditions here. we want to ensure that Wait()
// will be called, and will return, on the other goroutine, no matter
// where it is blocked. If it's blocked on ReadBytes(), we will kill it
// (first with SIGTERM, then with SIGKILL) and ReadBytes will return
// with EOF. If it's blocked on Wait(), then one of the kill signals
// will succeed and unblock it.
go processAuthScriptOutput(cmd, stdout, channel)
outputTimer := time.NewTimer(config.Timeout)
select {
case response := <-channel:
return response.output, response.err
case <-outputTimer.C:
}
err = errTimedOut
cmd.Process.Signal(syscall.SIGTERM)
termTimer := time.NewTimer(config.Timeout)
select {
case <-channel:
return
case <-termTimer.C:
}
cmd.Process.Kill()
return
}
func processAuthScriptOutput(cmd *exec.Cmd, stdout io.Reader, channel chan authScriptResponse) {
var response authScriptResponse
var out AuthScriptOutput
type IPScriptResult uint
reader := bufio.NewReader(stdout)
outBytes, err := reader.ReadBytes('\n')
if err == nil {
err = json.Unmarshal(outBytes, &out)
if err == nil {
response.output = out
if out.Error != "" {
err = fmt.Errorf("Authentication process reported error: %s", out.Error)
}
}
}
response.err = err
const (
IPNotChecked IPScriptResult = 0
IPAccepted IPScriptResult = 1
IPBanned IPScriptResult = 2
IPRequireSASL IPScriptResult = 3
)
// always call Wait() to ensure resource cleanup
err = cmd.Wait()
if err != nil {
response.err = err
}
channel <- response
type IPScriptInput struct {
IP string `json:"ip"`
}
type IPScriptOutput struct {
Result IPScriptResult `json:"result"`
BanMessage string `json:"banMessage"`
// for caching: the network to which this result is applicable, and a TTL in seconds:
CacheNet string `json:"cacheNet"`
CacheSeconds int `json:"cacheSeconds"`
Error string `json:"error"`
}
func CheckIPBan(sem utils.Semaphore, config ScriptConfig, addr net.IP) (output IPScriptOutput, err error) {
if sem != nil {
sem.Acquire()
defer sem.Release()
}
inputBytes, err := json.Marshal(IPScriptInput{IP: addr.String()})
if err != nil {
return
}
outBytes, err := RunScript(config.Command, config.Args, inputBytes, config.Timeout, config.KillTimeout)
if err != nil {
return
}
err = json.Unmarshal(outBytes, &output)
if err != nil {
return
}
if output.Error != "" {
err = fmt.Errorf("IP ban process reported error: %s", output.Error)
} else if !(IPAccepted <= output.Result && output.Result <= IPRequireSASL) {
err = fmt.Errorf("Invalid result from IP checking script: %d", output.Result)
}
return
}

15
irc/client.go
View File

@ -101,6 +101,7 @@ type Client struct {
cloakedHostname string
realname string
realIP net.IP
requireSASL bool
registered bool
registrationTimer *time.Timer
resumeID string
@ -297,8 +298,9 @@ type ClientDetails struct {
// RunClient sets up a new client and runs its goroutine.
func (server *Server) RunClient(conn IRCConn) {
config := server.Config()
wConn := conn.UnderlyingConn()
var isBanned bool
var isBanned, requireSASL bool
var banMsg string
realIP := utils.AddrToIP(wConn.RemoteAddr())
var proxiedIP net.IP
@ -313,7 +315,10 @@ func (server *Server) RunClient(conn IRCConn) {
proxiedIP = wConn.ProxiedIP
ipToCheck = proxiedIP
}
isBanned, banMsg = server.checkBans(ipToCheck)
// XXX only run the check script now if the IP cannot be replaced by PROXY or WEBIRC,
// otherwise we'll do it in ApplyProxiedIP.
checkScripts := proxiedIP != nil || !utils.IPInNets(realIP, config.Server.proxyAllowedFromNets)
isBanned, requireSASL, banMsg = server.checkBans(config, ipToCheck, checkScripts)
}
if isBanned {
@ -327,7 +332,6 @@ func (server *Server) RunClient(conn IRCConn) {
server.logger.Info("connect-ip", fmt.Sprintf("Client connecting: real IP %v, proxied IP %v", realIP, proxiedIP))
now := time.Now().UTC()
config := server.Config()
// give them 1k of grace over the limit:
socket := NewSocket(conn, config.Server.MaxSendQBytes)
client := &Client{
@ -347,6 +351,7 @@ func (server *Server) RunClient(conn IRCConn) {
nickMaskString: "*", // * is used until actual nick is given
realIP: realIP,
proxiedIP: proxiedIP,
requireSASL: requireSASL,
}
client.writerSemaphore.Initialize(1)
client.history.Initialize(config.History.ClientLength, time.Duration(config.History.AutoresizeWindow))
@ -554,7 +559,7 @@ const (
authFailSaslRequired
)
func (client *Client) isAuthorized(server *Server, config *Config, session *Session) AuthOutcome {
func (client *Client) isAuthorized(server *Server, config *Config, session *Session, forceRequireSASL bool) AuthOutcome {
saslSent := client.account != ""
// PASS requirement
if (config.Server.passwordBytes != nil) && session.passStatus != serverPassSuccessful && !(config.Accounts.SkipServerPassword && saslSent) {
@ -565,7 +570,7 @@ func (client *Client) isAuthorized(server *Server, config *Config, session *Sess
return authFailTorSaslRequired
}
// finally, enforce require-sasl
if !saslSent && (config.Accounts.RequireSasl.Enabled || server.Defcon() <= 2) &&
if !saslSent && (forceRequireSASL || config.Accounts.RequireSasl.Enabled || server.Defcon() <= 2) &&
!utils.IPInNets(session.IP(), config.Accounts.RequireSasl.exemptedNets) {
return authFailSaslRequired
}

22
irc/config.go
View File

@ -282,13 +282,18 @@ type AccountConfig struct {
AuthScript AuthScriptConfig `yaml:"auth-script"`
}
type ScriptConfig struct {
Enabled bool
Command string
Args []string
Timeout time.Duration
KillTimeout time.Duration `yaml:"kill-timeout"`
MaxConcurrency uint `yaml:"max-concurrency"`
}
type AuthScriptConfig struct {
Enabled bool
Command string
Args []string
Autocreate bool
Timeout time.Duration
KillTimeout time.Duration `yaml:"kill-timeout"`
ScriptConfig `yaml:",inline"`
Autocreate bool
}
// AccountRegistrationConfig controls account registration.
@ -526,8 +531,9 @@ type Config struct {
supportedCaps *caps.Set
capValues caps.Values
Casemapping Casemapping
EnforceUtf8 bool `yaml:"enforce-utf8"`
OutputPath string `yaml:"output-path"`
EnforceUtf8 bool `yaml:"enforce-utf8"`
OutputPath string `yaml:"output-path"`
IPCheckScript ScriptConfig `yaml:"ip-check-script"`
}
Roleplay struct {

3
irc/gateways.go
View File

@ -77,10 +77,11 @@ func (client *Client) ApplyProxiedIP(session *Session, proxiedIP net.IP, tls boo
}
proxiedIP = proxiedIP.To16()
isBanned, banMsg := client.server.checkBans(proxiedIP)
isBanned, requireSASL, banMsg := client.server.checkBans(client.server.Config(), proxiedIP, true)
if isBanned {
return errBanned, banMsg
}
client.requireSASL = requireSASL
// successfully added a limiter entry for the proxied IP;
// remove the entry for the real IP if applicable (#197)
client.server.connectionLimiter.RemoveClient(session.realIP)

83
irc/script.go Normal file
View File

@ -0,0 +1,83 @@
// Copyright (c) 2020 Shivaram Lingamneni
// released under the MIT license
package irc
import (
"bufio"
"io"
"os/exec"
"syscall"
"time"
)
// general-purpose scripting API for oragono "plugins"
// invoke a command, send it a single newline-terminated string of bytes (typically JSON)
// get back another newline-terminated string of bytes (or an error)
// internal tupling of output and error for passing over a channel
type scriptResponse struct {
output []byte
err error
}
func RunScript(command string, args []string, input []byte, timeout, killTimeout time.Duration) (output []byte, err error) {
cmd := exec.Command(command, args...)
stdin, err := cmd.StdinPipe()
if err != nil {
return
}
stdout, err := cmd.StdoutPipe()
if err != nil {
return
}
channel := make(chan scriptResponse, 1)
err = cmd.Start()
if err != nil {
return
}
stdin.Write(input)
stdin.Write([]byte{'\n'})
// lots of potential race conditions here. we want to ensure that Wait()
// will be called, and will return, on the other goroutine, no matter
// where it is blocked. If it's blocked on ReadBytes(), we will kill it
// (first with SIGTERM, then with SIGKILL) and ReadBytes will return
// with EOF. If it's blocked on Wait(), then one of the kill signals
// will succeed and unblock it.
go processScriptOutput(cmd, stdout, channel)
outputTimer := time.NewTimer(timeout)
select {
case response := <-channel:
return response.output, response.err
case <-outputTimer.C:
}
err = errTimedOut
cmd.Process.Signal(syscall.SIGTERM)
termTimer := time.NewTimer(killTimeout)
select {
case <-channel:
return
case <-termTimer.C:
}
cmd.Process.Kill()
return
}
func processScriptOutput(cmd *exec.Cmd, stdout io.Reader, channel chan scriptResponse) {
var response scriptResponse
reader := bufio.NewReader(stdout)
response.output, response.err = reader.ReadBytes('\n')
// always call Wait() to ensure resource cleanup
err := cmd.Wait()
if err != nil {
response.err = err
}
channel <- response
}

2
irc/semaphores.go
View File

@ -27,6 +27,8 @@ type ServerSemaphores struct {
// each distinct operation MUST have its own semaphore;
// methods that acquire a semaphore MUST NOT call methods that acquire another
ClientDestroy utils.Semaphore
IPCheckScript utils.Semaphore
AuthScript utils.Semaphore
}
// Initialize initializes a set of server semaphores.

86
irc/server.go
View File

@ -150,10 +150,10 @@ func (server *Server) Run() {
}
}
func (server *Server) checkBans(ipaddr net.IP) (banned bool, message string) {
func (server *Server) checkBans(config *Config, ipaddr net.IP, checkScripts bool) (banned bool, requireSASL bool, message string) {
if server.Defcon() == 1 {
if !(ipaddr.IsLoopback() || utils.IPInNets(ipaddr, server.Config().Server.secureNets)) {
return true, "New connections to this server are temporarily restricted"
return true, false, "New connections to this server are temporarily restricted"
}
}
@ -161,7 +161,7 @@ func (server *Server) checkBans(ipaddr net.IP) (banned bool, message string) {
isBanned, info := server.dlines.CheckIP(ipaddr)
if isBanned {
server.logger.Info("connect-ip", fmt.Sprintf("Client from %v rejected by d-line", ipaddr))
return true, info.BanMessage("You are banned from this server (%s)")
return true, false, info.BanMessage("You are banned from this server (%s)")
}
// check connection limits
@ -169,27 +169,55 @@ func (server *Server) checkBans(ipaddr net.IP) (banned bool, message string) {
if err == connection_limits.ErrLimitExceeded {
// too many connections from one client, tell the client and close the connection
server.logger.Info("connect-ip", fmt.Sprintf("Client from %v rejected for connection limit", ipaddr))
return true, "Too many clients from your network"
return true, false, "Too many clients from your network"
} else if err == connection_limits.ErrThrottleExceeded {
duration := server.Config().Server.IPLimits.BanDuration
if duration == 0 {
return false, ""
duration := config.Server.IPLimits.BanDuration
if duration != 0 {
server.dlines.AddIP(ipaddr, duration, throttleMessage,
"Exceeded automated connection throttle", "auto.connection.throttler")
// they're DLINE'd for 15 minutes or whatever, so we can reset the connection throttle now,
// and once their temporary DLINE is finished they can fill up the throttler again
server.connectionLimiter.ResetThrottle(ipaddr)
}
server.dlines.AddIP(ipaddr, duration, throttleMessage, "Exceeded automated connection throttle", "auto.connection.throttler")
// they're DLINE'd for 15 minutes or whatever, so we can reset the connection throttle now,
// and once their temporary DLINE is finished they can fill up the throttler again
server.connectionLimiter.ResetThrottle(ipaddr)
// this might not show up properly on some clients, but our objective here is just to close it out before it has a load impact on us
server.logger.Info(
"connect-ip",
fmt.Sprintf("Client from %v exceeded connection throttle, d-lining for %v", ipaddr, duration))
return true, throttleMessage
return true, false, throttleMessage
} else if err != nil {
server.logger.Warning("internal", "unexpected ban result", err.Error())
}
return false, ""
if checkScripts && config.Server.IPCheckScript.Enabled {
output, err := CheckIPBan(server.semaphores.IPCheckScript, config.Server.IPCheckScript, ipaddr)
if err != nil {
server.logger.Error("internal", "couldn't check IP ban script", ipaddr.String(), err.Error())
return false, false, ""
}
// TODO: currently no way to cache results other than IPBanned
if output.Result == IPBanned && output.CacheSeconds != 0 {
network, err := utils.NormalizedNetFromString(output.CacheNet)
if err != nil {
server.logger.Error("internal", "invalid dline net from IP ban script", ipaddr.String(), output.CacheNet)
} else {
dlineDuration := time.Duration(output.CacheSeconds) * time.Second
err := server.dlines.AddNetwork(network, dlineDuration, output.BanMessage, "", "")
if err != nil {
server.logger.Error("internal", "couldn't set dline from IP ban script", ipaddr.String(), err.Error())
}
}
}
if output.Result == IPBanned {
// XXX roll back IP connection/throttling addition for the IP
server.connectionLimiter.RemoveClient(ipaddr)
server.logger.Info("connect-ip", "Rejected client due to ip-check-script", ipaddr.String())
return true, false, output.BanMessage
} else if output.Result == IPRequireSASL {
server.logger.Info("connect-ip", "Requiring SASL from client due to ip-check-script", ipaddr.String())
return false, true, ""
}
}
return false, false, ""
}
func (server *Server) checkTorLimits() (banned bool, message string) {
@ -214,6 +242,12 @@ func (server *Server) tryRegister(c *Client, session *Session) (exiting bool) {
return // whether we succeeded or failed, either way `c` is not getting registered
}
// XXX PROXY or WEBIRC MUST be sent as the first line of the session;
// if we are here at all that means we have the final value of the IP
if session.rawHostname == "" {
session.client.lookupHostname(session, false)
}
// try to complete registration normally
// XXX(#1057) username can be filled in by an ident query without the client
// having sent USER: check for both username and realname to ensure they did
@ -229,7 +263,7 @@ func (server *Server) tryRegister(c *Client, session *Session) (exiting bool) {
// client MUST send PASS if necessary, or authenticate with SASL if necessary,
// before completing the other registration commands
config := server.Config()
authOutcome := c.isAuthorized(server, config, session)
authOutcome := c.isAuthorized(server, config, session, c.requireSASL)
var quitMessage string
switch authOutcome {
case authFailPass:
@ -244,12 +278,6 @@ func (server *Server) tryRegister(c *Client, session *Session) (exiting bool) {
return true
}
// we have the final value of the IP address: do the hostname lookup
// (nickmask will be set below once nickname assignment succeeds)
if session.rawHostname == "" {
session.client.lookupHostname(session, false)
}
rb := NewResponseBuffer(session)
nickError := performNickChange(server, c, c, session, c.preregNick, rb)
rb.Send(true)
@ -489,6 +517,9 @@ func (server *Server) applyConfig(config *Config) (err error) {
return fmt.Errorf("Cannot enable or disable relaying after launching the server, rehash aborted")
} else if oldConfig.Server.Relaymsg.Separators != config.Server.Relaymsg.Separators {
return fmt.Errorf("Cannot change relaying separators after launching the server, rehash aborted")
} else if oldConfig.Server.IPCheckScript.MaxConcurrency != config.Server.IPCheckScript.MaxConcurrency ||
oldConfig.Accounts.AuthScript.MaxConcurrency != config.Accounts.AuthScript.MaxConcurrency {
return fmt.Errorf("Cannot change max-concurrency for scripts after launching the server, rehash aborted")
}
}
@ -513,6 +544,17 @@ func (server *Server) applyConfig(config *Config) (err error) {
server.logger.Debug("server", "Regenerating HELP indexes for new languages")
server.helpIndexManager.GenerateIndices(config.languageManager)
if initial {
maxIPConc := int(config.Server.IPCheckScript.MaxConcurrency)
if maxIPConc != 0 {
server.semaphores.IPCheckScript.Initialize(maxIPConc)
}
maxAuthConc := int(config.Accounts.AuthScript.MaxConcurrency)
if maxAuthConc != 0 {
server.semaphores.AuthScript.Initialize(maxAuthConc)
}
}
if oldConfig != nil {
// if certain features were enabled by rehash, we need to load the corresponding data
// from the store