Re: [BUG] selftests/net: icmp_redirect.sh: 12 out of 40 test result with [FAIL]

From: Mirsad Todorovac
Date: Tue Mar 19 2024 - 00:54:05 EST


On 3/18/24 15:42, David Ahern wrote:
On 3/17/24 8:38 PM, Hangbin Liu wrote:
Wild guess, the last change of icmp_redirect is my netns update. Maybe
there are something default sysctl settings in netns cause the error?

It is most likely sysctl settings. It would be good to chase those down
and make sure we have the script setting them.

Mirsad: What OS are you testing with? That script has a verbose option
(-v) to get more output like the commands run and pause-on-fail (-p) to
manually debug at that point.

Hi, David,

I am running an Ubuntu 22.04 LTS box, with the iptools upgraded to iproute2-next
tree of March 15th, on the torvalds tree.

Right now I have tried it against the net-next tree, and I get the same result:

# timeout set to 3600
# selftests: net: icmp_redirect.sh
#
# ###########################################################################
# Legacy routing
# ###########################################################################
#
# TEST: IPv4: redirect exception [FAIL]
# TEST: IPv6: redirect exception [ OK ]
# TEST: IPv4: redirect exception plus mtu [FAIL]
# TEST: IPv6: redirect exception plus mtu [ OK ]
# TEST: IPv4: routing reset [ OK ]
# TEST: IPv6: routing reset [ OK ]
# TEST: IPv4: mtu exception [ OK ]
# TEST: IPv6: mtu exception [ OK ]
# TEST: IPv4: mtu exception plus redirect [FAIL]
# TEST: IPv6: mtu exception plus redirect [ OK ]
#
# ###########################################################################
# Legacy routing with VRF
# ###########################################################################
#
# TEST: IPv4: redirect exception [FAIL]
# TEST: IPv6: redirect exception [ OK ]
# TEST: IPv4: redirect exception plus mtu [FAIL]
# TEST: IPv6: redirect exception plus mtu [ OK ]
# TEST: IPv4: routing reset [ OK ]
# TEST: IPv6: routing reset [ OK ]
# TEST: IPv4: mtu exception [ OK ]
# TEST: IPv6: mtu exception [ OK ]
# TEST: IPv4: mtu exception plus redirect [FAIL]
# TEST: IPv6: mtu exception plus redirect [ OK ]
#
# ###########################################################################
# Routing with nexthop objects
# ###########################################################################
#
# TEST: IPv4: redirect exception [FAIL]
# TEST: IPv6: redirect exception [ OK ]
# TEST: IPv4: redirect exception plus mtu [FAIL]
# TEST: IPv6: redirect exception plus mtu [ OK ]
# TEST: IPv4: routing reset [ OK ]
# TEST: IPv6: routing reset [ OK ]
# TEST: IPv4: mtu exception [ OK ]
# TEST: IPv6: mtu exception [ OK ]
# TEST: IPv4: mtu exception plus redirect [FAIL]
# TEST: IPv6: mtu exception plus redirect [ OK ]
#
# ###########################################################################
# Routing with nexthop objects and VRF
# ###########################################################################
#
# TEST: IPv4: redirect exception [FAIL]
# TEST: IPv6: redirect exception [ OK ]
# TEST: IPv4: redirect exception plus mtu [FAIL]
# TEST: IPv6: redirect exception plus mtu [ OK ]
# TEST: IPv4: routing reset [ OK ]
# TEST: IPv6: routing reset [ OK ]
# TEST: IPv4: mtu exception [ OK ]
# TEST: IPv6: mtu exception [ OK ]
# TEST: IPv4: mtu exception plus redirect [FAIL]
# TEST: IPv6: mtu exception plus redirect [ OK ]
#
# Tests passed: 28
# Tests failed: 12
# Tests xfailed: 0
not ok 45 selftests: net: icmp_redirect.sh # exit=1

So, it is probably the sysctl you said, but I cannot tell which one.

My /etc/sysctl.conf looks like this (I think something like Libreswan VPN required these
to be redirects turned off):

#
# /etc/sysctl.conf - Configuration file for setting system variables
# See /etc/sysctl.d/ for additional system variables.
# See sysctl.conf (5) for information.
#

#kernel.domainname = example.com

# Uncomment the following to stop low-level messages on console
#kernel.printk = 3 4 1 3

###################################################################
# Functions previously found in netbase
#

# Uncomment the next two lines to enable Spoof protection (reverse-path filter)
# Turn on Source Address Verification in all interfaces to
# prevent some spoofing attacks
#net.ipv4.conf.default.rp_filter=1
#net.ipv4.conf.all.rp_filter=1

# Uncomment the next line to enable TCP/IP SYN cookies
# See http://lwn.net/Articles/277146/
# Note: This may impact IPv6 TCP sessions too
#net.ipv4.tcp_syncookies=1

# Uncomment the next line to enable packet forwarding for IPv4
net.ipv4.ip_forward=1

# Uncomment the next line to enable packet forwarding for IPv6
# Enabling this option disables Stateless Address Autoconfiguration
# based on Router Advertisements for this host
#net.ipv6.conf.all.forwarding=1

net.ipv4.conf.default.rp_filter = 0
net.ipv4.conf.all.rp_filter = 0


###################################################################
# Additional settings - these settings can improve the network
# security of the host and prevent against some network attacks
# including spoofing attacks and man in the middle attacks through
# redirection. Some network environments, however, require that these
# settings are disabled so review and enable them as needed.
#
# Do not accept ICMP redirects (prevent MITM attacks)
net.ipv4.conf.all.accept_redirects = 0
net.ipv6.conf.all.accept_redirects = 0
net.ipv4.conf.default.accept_redirects = 0
net.ipv6.conf.default.accept_redirects = 0
# _or_
# Accept ICMP redirects only for gateways listed in our default
# gateway list (enabled by default)
# net.ipv4.conf.all.secure_redirects = 1
#
# Do not send ICMP redirects (we are not a router)
net.ipv4.conf.all.send_redirects = 0
net.ipv4.conf.default.send_redirects = 0
net.ipv4.icmp_ignore_bogus_error_responses = 1
#
# Do not accept IP source route packets (we are not a router)
net.ipv4.conf.all.accept_source_route = 0
net.ipv6.conf.all.accept_source_route = 0
#
# Log Martian Packets
net.ipv4.conf.all.log_martians = 0
net.ipv4.conf.default.log_martians = 0
#

###################################################################
# Magic system request Key
# 0=disable, 1=enable all, >1 bitmask of sysrq functions
# See https://www.kernel.org/doc/html/latest/admin-guide/sysrq.html
# for what other values do
#kernel.sysrq=438

Thank you.

Best regards,
Mirsad

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Description: application/xz