kern/133572: incoming PPTP connection hangs the system

[Dennis Melentyev]

>Number:         133572
>Category:       kern
>Synopsis:       incoming PPTP connection hangs the system
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Fri Apr 10 17:20:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Dennis Melentyev
>Release:        FreeBSD 7.2-PRERELEASE
>Organization:
DMS-Consulting.com
>Environment:
FreeBSD inet-gw.dynamo-kiev.local 7.2-PRERELEASE FreeBSD 7.2-PRERELEASE #0: Thu Apr  2 14:27:51 EEST 2009     root at inet-gw.dynamo-kiev.local:/usr/obj/usr/src/sys/INETGWI386  i386

>Description:
Upgrading from 7.1-RELEASE to 7.2-PRERELEASE as of Apr 2nd caused to system  hangs on incoming PPTP connection.
No panic, no dumps. Just plain frozen everything (network, console, etc).

I am using MPD4 for incoming PPTP sessions with minimal tweaks.
Two external internet links.
Outgoing sessions are perfect.

For incoming sessions I used to try following PF rules:
pass in quick on $uts_if reply-to ( $uts_if $uts_gw ) inet proto gre from any to $uts_addr keep state
pass in quick on $vpn_if reply-to ( $vpn_if $vpn_gw ) inet proto gre from any to $vpn_addr keep state

This doesn't work at all in 7.1-RELEASE (gre packets always got routed to default route), but could trigger the problem in 7.2-PRERELEASE.

Kernel config attached
>How-To-Repeat:
use two external interfaces, with NAT.
mpd4 set up for incoming clients using PPTP
PF set up to reply packets go back via the same interface (TCP/UDP/ICMP/GRE)
Default route points to one of the interfaces.
Kernel has 
options         ROUTETABLES=4
But this tables are not used in no way.

>Fix:
Workaround - deny incoming PPTP. :(

Patch attached with submission follows:

#
# GENERIC -- Generic kernel configuration file for FreeBSD/i386
#
# For more information on this file, please read the handbook section on
# Kernel Configuration Files:
#
#    http://www.FreeBSD.org/doc/en_US.ISO8859-1/books/handbook/kernelconfig-config.html
#
# The handbook is also available locally in /usr/share/doc/handbook
# if you've installed the doc distribution, otherwise always see the
# FreeBSD World Wide Web server (http://www.FreeBSD.org/) for the
# latest information.
#
# An exhaustive list of options and more detailed explanations of the
# device lines is also present in the ../../conf/NOTES and NOTES files.
# If you are in doubt as to the purpose or necessity of a line, check first
# in NOTES.
#
# $FreeBSD: src/sys/i386/conf/GENERIC,v 1.474.2.17 2009/03/12 03:09:11 bms Exp $

cpu		I486_CPU
cpu		I586_CPU
cpu		I686_CPU
ident		INETGWI386

# To statically compile in device wiring instead of /boot/device.hints
#hints		"GENERIC.hints"		# Default places to look for devices.

makeoptions	DEBUG=-g		# Build kernel with gdb(1) debug symbols

options		ROUTETABLES=4
options		IPSEC			# IPSec support
#options		IPSEC_ESP
#options		IPSEC_DEBUG
device		crypto


#options 	SCHED_4BSD		# 4BSD scheduler
options 	SCHED_ULE		# ULE scheduler
options 	PREEMPTION		# Enable kernel thread preemption
options 	INET			# InterNETworking
options 	INET6			# IPv6 communications protocols
options 	SCTP			# Stream Control Transmission Protocol
options 	FFS			# Berkeley Fast Filesystem
options 	SOFTUPDATES		# Enable FFS soft updates support
options 	UFS_ACL			# Support for access control lists
options 	UFS_DIRHASH		# Improve performance on big directories
options 	UFS_GJOURNAL		# Enable gjournal-based UFS journaling
options 	MD_ROOT			# MD is a potential root device
options 	NFSCLIENT		# Network Filesystem Client
options 	NFSSERVER		# Network Filesystem Server
options 	NFSLOCKD		# Network Lock Manager
options 	NFS_ROOT		# NFS usable as /, requires NFSCLIENT
options 	MSDOSFS			# MSDOS Filesystem
options 	CD9660			# ISO 9660 Filesystem
options 	PROCFS			# Process filesystem (requires PSEUDOFS)
options 	PSEUDOFS		# Pseudo-filesystem framework
options 	GEOM_PART_GPT		# GUID Partition Tables.
options 	GEOM_LABEL		# Provides labelization
options 	COMPAT_43TTY		# BSD 4.3 TTY compat [KEEP THIS!]
options 	COMPAT_FREEBSD4		# Compatible with FreeBSD4
options 	COMPAT_FREEBSD5		# Compatible with FreeBSD5
options 	COMPAT_FREEBSD6		# Compatible with FreeBSD6
options 	SCSI_DELAY=5000		# Delay (in ms) before probing SCSI
options 	KTRACE			# ktrace(1) support
options 	STACK			# stack(9) support
options 	SYSVSHM			# SYSV-style shared memory
options 	SYSVMSG			# SYSV-style message queues
options 	SYSVSEM			# SYSV-style semaphores
options 	_KPOSIX_PRIORITY_SCHEDULING # POSIX P1003_1B real-time extensions
options 	KBD_INSTALL_CDEV	# install a CDEV entry in /dev
options 	ADAPTIVE_GIANT		# Giant mutex is adaptive.
options 	STOP_NMI		# Stop CPUS using NMI instead of IPI
options 	AUDIT			# Security event auditing

#ALTQ Support
options         ALTQ
options ALTQ_CBQ        # Class Bases Queueing
options ALTQ_RED        # Random Early Drop
options ALTQ_RIO        # RED In/Out
options ALTQ_HFSC       # Hierarchical Packet Scheduler
options ALTQ_CDNR       # Traffic conditioner
options ALTQ_PRIQ       # Priority Queueing
#options 	KDTRACE_HOOKS		# Kernel DTrace hooks

# To make an SMP kernel, the next two lines are needed
options 	SMP			# Symmetric MultiProcessor Kernel
device		apic			# I/O APIC

# CPU frequency control
device		cpufreq

# Bus support.
device		eisa
device		pci

# Floppy drives
device		fdc

# ATA and ATAPI devices
device		ata
device		atadisk		# ATA disk drives
device		ataraid		# ATA RAID drives
device		atapicd		# ATAPI CDROM drives
device		atapifd		# ATAPI floppy drives
device		atapist		# ATAPI tape drives
options 	ATA_STATIC_ID	# Static device numbering

# SCSI Controllers
device		ahb		# EISA AHA1742 family
device		ahc		# AHA2940 and onboard AIC7xxx devices
options 	AHC_REG_PRETTY_PRINT	# Print register bitfields in debug
					# output.  Adds ~128k to driver.
device		ahd		# AHA39320/29320 and onboard AIC79xx devices
options 	AHD_REG_PRETTY_PRINT	# Print register bitfields in debug
					# output.  Adds ~215k to driver.
device		amd		# AMD 53C974 (Tekram DC-390(T))
device		hptiop		# Highpoint RocketRaid 3xxx series
device		isp		# Qlogic family
#device 	ispfw		# Firmware for QLogic HBAs- normally a module
device		mpt		# LSI-Logic MPT-Fusion
#device		ncr		# NCR/Symbios Logic
device		sym		# NCR/Symbios Logic (newer chipsets + those of `ncr')
device		trm		# Tekram DC395U/UW/F DC315U adapters

device		adv		# Advansys SCSI adapters
device		adw		# Advansys wide SCSI adapters
device		aha		# Adaptec 154x SCSI adapters
device		aic		# Adaptec 15[012]x SCSI adapters, AIC-6[23]60.
device		bt		# Buslogic/Mylex MultiMaster SCSI adapters

device		ncv		# NCR 53C500
device		nsp		# Workbit Ninja SCSI-3
device		stg		# TMC 18C30/18C50

# SCSI peripherals
device		scbus		# SCSI bus (required for SCSI)
device		ch		# SCSI media changers
device		da		# Direct Access (disks)
device		sa		# Sequential Access (tape etc)
device		cd		# CD
device		pass		# Passthrough device (direct SCSI access)
device		ses		# SCSI Environmental Services (and SAF-TE)

# RAID controllers interfaced to the SCSI subsystem
device		amr		# AMI MegaRAID
device		arcmsr		# Areca SATA II RAID
device		asr		# DPT SmartRAID V, VI and Adaptec SCSI RAID
device		ciss		# Compaq Smart RAID 5*
device		dpt		# DPT Smartcache III, IV - See NOTES for options
device		hptmv		# Highpoint RocketRAID 182x
device		hptrr		# Highpoint RocketRAID 17xx, 22xx, 23xx, 25xx
device		iir		# Intel Integrated RAID
device		ips		# IBM (Adaptec) ServeRAID
device		mly		# Mylex AcceleRAID/eXtremeRAID
device		twa		# 3ware 9000 series PATA/SATA RAID

# RAID controllers
device		aac		# Adaptec FSA RAID
device		aacp		# SCSI passthrough for aac (requires CAM)
device		ida		# Compaq Smart RAID
device		mfi		# LSI MegaRAID SAS
device		mlx		# Mylex DAC960 family
device		pst		# Promise Supertrak SX6000
device		twe		# 3ware ATA RAID

# atkbdc0 controls both the keyboard and the PS/2 mouse
device		atkbdc		# AT keyboard controller
device		atkbd		# AT keyboard
device		psm		# PS/2 mouse

device		kbdmux		# keyboard multiplexer

device		vga		# VGA video card driver

device		splash		# Splash screen and screen saver support

# syscons is the default console driver, resembling an SCO console
device		sc

device		agp		# support several AGP chipsets

# Power management support (see NOTES for more options)
#device		apm
# Add suspend/resume support for the i8254.
device		pmtimer

# PCCARD (PCMCIA) support
# PCMCIA and cardbus bridge support
device		cbb		# cardbus (yenta) bridge
device		pccard		# PC Card (16-bit) bus
device		cardbus		# CardBus (32-bit) bus

# Serial (COM) ports
device		sio		# 8250, 16[45]50 based serial ports
device		uart		# Generic UART driver

# Parallel port
device		ppc
device		ppbus		# Parallel port bus (required)
device		lpt		# Printer
device		plip		# TCP/IP over parallel
device		ppi		# Parallel port interface device
#device		vpo		# Requires scbus and da

# If you've got a "dumb" serial or parallel PCI card that is
# supported by the puc(4) glue driver, uncomment the following
# line to enable it (connects to sio, uart and/or ppc drivers):
#device		puc

# PCI Ethernet NICs.
device		de		# DEC/Intel DC21x4x (``Tulip'')
device		em		# Intel PRO/1000 Gigabit Ethernet Family
device		igb		# Intel PRO/1000 PCIE Server Gigabit Family
device		ixgb		# Intel PRO/10GbE Ethernet Card
device		le		# AMD Am7900 LANCE and Am79C9xx PCnet
device		txp		# 3Com 3cR990 (``Typhoon'')
device		vx		# 3Com 3c590, 3c595 (``Vortex'')

# PCI Ethernet NICs that use the common MII bus controller code.
# NOTE: Be sure to keep the 'device miibus' line in order to use these NICs!
device		miibus		# MII bus support
device		age		# Attansic/Atheros L1 Gigabit Ethernet
device		ale		# Atheros AR8121/AR8113/AR8114 Ethernet
device		bce		# Broadcom BCM5706/BCM5708 Gigabit Ethernet
device		bfe		# Broadcom BCM440x 10/100 Ethernet
device		bge		# Broadcom BCM570xx Gigabit Ethernet
device		dc		# DEC/Intel 21143 and various workalikes
device		et		# Agere ET1310 10/100/Gigabit Ethernet
device		fxp		# Intel EtherExpress PRO/100B (82557, 82558)
device		jme		# JMicron JMC250 Gigabit/JMC260 Fast Ethernet
device		lge		# Level 1 LXT1001 gigabit Ethernet
device		msk		# Marvell/SysKonnect Yukon II Gigabit Ethernet
device		nfe		# nVidia nForce MCP on-board Ethernet
device		nge		# NatSemi DP83820 gigabit Ethernet
#device		nve		# nVidia nForce MCP on-board Ethernet Networking
device		pcn		# AMD Am79C97x PCI 10/100 (precedence over 'le')
device		re		# RealTek 8139C+/8169/8169S/8110S
device		rl		# RealTek 8129/8139
device		sf		# Adaptec AIC-6915 (``Starfire'')
device		sis		# Silicon Integrated Systems SiS 900/SiS 7016
device		sk		# SysKonnect SK-984x & SK-982x gigabit Ethernet
device		ste		# Sundance ST201 (D-Link DFE-550TX)
device		stge		# Sundance/Tamarack TC9021 gigabit Ethernet
device		ti		# Alteon Networks Tigon I/II gigabit Ethernet
device		tl		# Texas Instruments ThunderLAN
device		tx		# SMC EtherPower II (83c170 ``EPIC'')
device		vge		# VIA VT612x gigabit Ethernet
device		vr		# VIA Rhine, Rhine II
device		wb		# Winbond W89C840F
device		xl		# 3Com 3c90x (``Boomerang'', ``Cyclone'')

# ISA Ethernet NICs.  pccard NICs included.
device		cs		# Crystal Semiconductor CS89x0 NIC
# 'device ed' requires 'device miibus'
device		ed		# NE[12]000, SMC Ultra, 3c503, DS8390 cards
device		ex		# Intel EtherExpress Pro/10 and Pro/10+
device		ep		# Etherlink III based cards
device		fe		# Fujitsu MB8696x based cards
device		ie		# EtherExpress 8/16, 3C507, StarLAN 10 etc.
device		sn		# SMC's 9000 series of Ethernet chips
device		xe		# Xircom pccard Ethernet

# Wireless NIC cards
device		wlan		# 802.11 support
device		wlan_wep	# 802.11 WEP support
device		wlan_ccmp	# 802.11 CCMP support
device		wlan_tkip	# 802.11 TKIP support
device		wlan_amrr	# AMRR transmit rate control algorithm
device		wlan_scan_ap	# 802.11 AP mode scanning
device		wlan_scan_sta	# 802.11 STA mode scanning
device		an		# Aironet 4500/4800 802.11 wireless NICs.
device		ath		# Atheros pci/cardbus NIC's
device		ath_hal		# Atheros HAL (Hardware Access Layer)
options		AH_SUPPORT_AR5416	# enable AR5416 tx/rx descriptors
device		ath_rate_sample	# SampleRate tx rate control for ath
device		awi		# BayStack 660 and others
device		ral		# Ralink Technology RT2500 wireless NICs.
device		wi		# WaveLAN/Intersil/Symbol 802.11 wireless NICs.
#device		wl		# Older non 802.11 Wavelan wireless NIC.

# Pseudo devices.
device		loop		# Network loopback
device		random		# Entropy device
device		ether		# Ethernet support
device		sl		# Kernel SLIP
device		ppp		# Kernel PPP
device		tun		# Packet tunnel.
device		pty		# Pseudo-ttys (telnet etc)
device		md		# Memory "disks"
device		gif		# IPv6 and IPv4 tunneling
device		faith		# IPv6-to-IPv4 relaying (translation)
device		firmware	# firmware assist module

# The `bpf' device enables the Berkeley Packet Filter.
# Be aware of the administrative consequences of enabling this!
# Note that 'bpf' is required for DHCP.
device		bpf		# Berkeley packet filter

# USB support
device		uhci		# UHCI PCI->USB interface
device		ohci		# OHCI PCI->USB interface
device		ehci		# EHCI PCI->USB interface (USB 2.0)
device		usb		# USB Bus (required)
#device		udbp		# USB Double Bulk Pipe devices
device		ugen		# Generic
device		uhid		# "Human Interface Devices"
device		ukbd		# Keyboard
device		ulpt		# Printer
device		umass		# Disks/Mass storage - Requires scbus and da
device		ums		# Mouse
device		ural		# Ralink Technology RT2500USB wireless NICs
device		rum		# Ralink Technology RT2501USB wireless NICs
device		urio		# Diamond Rio 500 MP3 player
device		uscanner	# Scanners
# USB Serial devices
device		ucom		# Generic com ttys
device		uark		# Technologies ARK3116 based serial adapters
device		ubsa		# Belkin F5U103 and compatible serial adapters
device		ubser		# BWCT console serial adapters
device		uftdi		# For FTDI usb serial adapters
device		uipaq		# Some WinCE based devices
device		uplcom		# Prolific PL-2303 serial adapters
device		uslcom		# SI Labs CP2101/CP2102 serial adapters
device		uvisor		# Visor and Palm devices
device		uvscom		# USB serial support for DDI pocket's PHS
# USB Ethernet, requires miibus
device		aue		# ADMtek USB Ethernet
device		axe		# ASIX Electronics USB Ethernet
device		cdce		# Generic USB over Ethernet
device		cue		# CATC USB Ethernet
device		kue		# Kawasaki LSI USB Ethernet
device		rue		# RealTek RTL8150 USB Ethernet

# FireWire support
device		firewire	# FireWire bus code
device		sbp		# SCSI over FireWire (Requires scbus and da)
device		fwe		# Ethernet over FireWire (non-standard!)
device		fwip		# IP over FireWire (RFC 2734,3146)
device		dcons		# Dumb console driver
device		dcons_crom	# Configuration ROM for dcons


>Release-Note:
>Audit-Trail:
>Unformatted: