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Filename Latest commit message Latest commit date
Guillaume Nault 8a0b8e26f7 netfilter: rpfilter: mask ecn bits before fib lookup
commit 2e5a6266fbb11ae93c468dfecab169aca9c27b43 upstream.

RT_TOS() only masks one of the two ECN bits. Therefore rpfilter_mt()
treats Not-ECT or ECT(1) packets in a different way than those with
ECT(0) or CE.

Reproducer:

  Create two netns, connected with a veth:
  $ ip netns add ns0
  $ ip netns add ns1
  $ ip link add name veth01 netns ns0 type veth peer name veth10 netns ns1
  $ ip -netns ns0 link set dev veth01 up
  $ ip -netns ns1 link set dev veth10 up
  $ ip -netns ns0 address add 192.0.2.10/32 dev veth01
  $ ip -netns ns1 address add 192.0.2.11/32 dev veth10

  Add a route to ns1 in ns0:
  $ ip -netns ns0 route add 192.0.2.11/32 dev veth01

  In ns1, only packets with TOS 4 can be routed to ns0:
  $ ip -netns ns1 route add 192.0.2.10/32 tos 4 dev veth10

  Ping from ns0 to ns1 works regardless of the ECN bits, as long as TOS
  is 4:
  $ ip netns exec ns0 ping -Q 4 192.0.2.11   # TOS 4, Not-ECT
    ... 0% packet loss ...
  $ ip netns exec ns0 ping -Q 5 192.0.2.11   # TOS 4, ECT(1)
    ... 0% packet loss ...
  $ ip netns exec ns0 ping -Q 6 192.0.2.11   # TOS 4, ECT(0)
    ... 0% packet loss ...
  $ ip netns exec ns0 ping -Q 7 192.0.2.11   # TOS 4, CE
    ... 0% packet loss ...

  Now use iptable's rpfilter module in ns1:
  $ ip netns exec ns1 iptables-legacy -t raw -A PREROUTING -m rpfilter --invert -j DROP

  Not-ECT and ECT(1) packets still pass:
  $ ip netns exec ns0 ping -Q 4 192.0.2.11   # TOS 4, Not-ECT
    ... 0% packet loss ...
  $ ip netns exec ns0 ping -Q 5 192.0.2.11   # TOS 4, ECT(1)
    ... 0% packet loss ...

  But ECT(0) and ECN packets are dropped:
  $ ip netns exec ns0 ping -Q 6 192.0.2.11   # TOS 4, ECT(0)
    ... 100% packet loss ...
  $ ip netns exec ns0 ping -Q 7 192.0.2.11   # TOS 4, CE
    ... 100% packet loss ...

After this patch, rpfilter doesn't drop ECT(0) and CE packets anymore.

Fixes: 8f97339d3f ("netfilter: add ipv4 reverse path filter match")
Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-01-27 11:47:52 +01:00
arch x86/cpu/amd: Set __max_die_per_package on AMD 2021-01-27 11:47:52 +01:00
block bfq: Fix computation of shallow depth 2021-01-19 18:26:15 +01:00
certs
crypto crypto: asym_tpm: correct zero out potential secrets 2021-01-12 20:16:17 +01:00
Documentation x86/xen: Add xen_no_vector_callback option to test PCI INTX delivery 2021-01-27 11:47:45 +01:00
drivers pinctrl: ingenic: Fix JZ4760 support 2021-01-27 11:47:52 +01:00
fs cifs: do not fail __smb_send_rqst if non-fatal signals are pending 2021-01-27 11:47:49 +01:00
include xen: Fix event channel callback via INTX/GSI 2021-01-27 11:47:44 +01:00
init exec: Transform exec_update_mutex into a rw_semaphore 2021-01-09 13:44:55 +01:00
ipc ipc/util.c: sysvipc_find_ipc() incorrectly updates position index 2020-05-20 08:20:16 +02:00
kernel bpf: Fix helper bpf_map_peek_elem_proto pointing to wrong callback 2021-01-23 15:57:56 +01:00
lib lib/raid6: Let $(UNROLL) rules work with macOS userland 2021-01-19 18:26:15 +01:00
LICENSES
mm mm, slub: consider rest of partial list if acquire_slab() fails 2021-01-19 18:26:18 +01:00
net netfilter: rpfilter: mask ecn bits before fib lookup 2021-01-27 11:47:52 +01:00
samples samples: bpf: Fix lwt_len_hist reusing previous BPF map 2020-12-30 11:51:12 +01:00
scripts depmod: handle the case of /sbin/depmod without /sbin in PATH 2021-01-12 20:16:10 +01:00
security dump_common_audit_data(): fix racy accesses to ->d_name 2021-01-19 18:26:16 +01:00
sound ASoC: Intel: haswell: Add missing pm_ops 2021-01-27 11:47:42 +01:00
tools selftests: net: fib_tests: remove duplicate log test 2021-01-27 11:47:48 +01:00
usr initramfs: restore default compression behavior 2020-04-08 09:08:38 +02:00
virt kvm: check tlbs_dirty directly 2021-01-12 20:16:22 +01:00
.clang-format
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.gitignore
.mailmap
COPYING
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Kbuild
Kconfig
MAINTAINERS Documentation/llvm: add documentation on building w/ Clang/LLVM 2020-08-26 10:40:46 +02:00
Makefile Linux 5.4.92 2021-01-23 15:58:01 +01:00
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