* [PATCH net-next v3 1/4] arp: discard invalid sha addr (b/mcast ARP poison)
2026-02-04 22:11 [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison) Marc Suñé
@ 2026-02-04 22:11 ` Marc Suñé
2026-02-05 10:54 ` Vadim Fedorenko
2026-02-04 22:11 ` [PATCH net-next v3 2/4] selftests/net: add no ARP b/mcast,null poison test Marc Suñé
` (3 subsequent siblings)
4 siblings, 1 reply; 8+ messages in thread
From: Marc Suñé @ 2026-02-04 22:11 UTC (permalink / raw)
To: kuba, willemdebruijn.kernel, pabeni
Cc: netdev, dborkman, vadim.fedorenko, Marc Suñé
Prior to this commit, the ARP implementation accepted ARP req/replies
with multicast (including broadcast) and null MAC addresses as Sender
HW Address (SHA), and updated the ARP cache for that neighbour.
Broadcast, multicast and null MAC addresses shall never be associated
with a unicast or a multicast IPv4 address (see RFC1812, section 3.3.2).
ARP poisioning with a broadcast MAC address and certain multicast
addresses, especially when poisoning a Gateway IP, have some undesired
implications compared to an ARP poisioning with a regular MAC (see
Note1).
Worth mentioning that if an attacker is able to ARP poison in
a L2 segment, that in itself is probably a bigger security threat
(Man-in-middle etc., see Note2).
However, since these MACs should never be announced as SHA,
discard/drop ARPs with SHA={b/mcast, null}, which prevents the
broadcast/multicast ARP poisoning vector.
Note1:
After a successful broadcast/multicast ARP poisioning attack:
1. Unicast packets and refresh ("targeted") ARPs sent to or via
the poisioned IP (e.g. the default GW) are flooded by
bridges/switches. That is in absence of other security controls.
Hardware swiches generally have rate-limits to prevent/mitigate
broadcast storms, since ARPs are usually answered by the CPU.
Legit unicast packets could be dropped (perf. degradation).
Most modern NICs implement some form of L2 MAC filtering to early
discard irrelevant packets. In contrast to an ARP poisoning
attack with any other MAC, both unicast and ARP ("targeted")
refresh packets are passed up to the Kernel networking stack
(for all hosts in the L2 segment).
2. A single forged ARP packet (e.g. for the Gateway IP) can produce
up to N "targeted" (to broadcast) ARPs, where N is the number of
hosts in the L2 segment that have an ARP entry for that IP
(e.g. GW), and some more traffic, since the real host will answer
to targeted refresh ARPs with their (real) reply.
This is a relatively low amount of traffic compared to 1).
3. An attacker could use this form of ARP poisoning to discover
all hosts in a L2 segment in a very short period of time with
one or few packets.
By poisoning e.g. the default GW (likely multiple times, to
avoid races with real gARPs from the GW), all hosts will eventually
issue refresh "targeted" ARPs for the GW IP with the broadcast MAC
address as destination. These packets will be flooded in the L2
segment, revealing the presence of hosts to the attacker.
For comparison:
* Passive ARP monitoring: also stealthy, but can take a long
time or not be possible at all in switches, as most refresh
ARPs are targeted.
* ARP req flooding: requires swiping the entire subnet. Noisy
and easy to detect.
* ICMP/L4 port scans: similar to the above.
4. In the unlikely case that hosts were to run with
`/proc/sys/net/ipv4/conf/*/arp_accept=1` (unsafe, and disabled
by default), poisoning with the broadcast MAC could be used to
create significantly more broadcast traffic (low-volume
amplification attack).
An attacker could send M fake gARP with a number of IP addresses,
where M is `/proc/sys/net/ipv4/neigh/*/gc_thresh3` (1024 by
default). This would result in M x R ARPs, where R is the number
of hosts in L2 segment with `arp_accept=1`, and likely other
(real) ARP replies coming from the attacked host. This starts to
get really relevant when R > 512, which is possible in large LANs
but not very common.
Note2:
However, broadcast ARP poisoning might be subtle and difficult to
spot. These ARP packets appear on the surface as regular broadcast
ARP requests (unless ARP hdr is inspected), traffic continues to
flow uninterrupted (unless broadcast rate-limit in switches kick-in)
and, the next refresh ARP reply (from the GW) or any (valid) gARP
from the GW, will restore the original MAC in the ARP table, making
the traffic flow normally again.
Signed-off-by: Marc Suñé <marcdevel@gmail.com>
---
net/ipv4/arp.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c
index c8c3e1713c0e..7dbb3fd5cc8a 100644
--- a/net/ipv4/arp.c
+++ b/net/ipv4/arp.c
@@ -800,6 +800,14 @@ static int arp_process(struct net *net, struct sock *sk, struct sk_buff *skb)
goto out_free_skb;
/*
+ * For Ethernet devices, Multicast/Broadcast and zero MAC addresses should
+ * never be announced and accepted as sender HW address (RFC1812, 3.3.2).
+ * Prevents Broadcast/Mcast ARP poisoning attack.
+ */
+ if (dev->type == ARPHRD_ETHER && !is_valid_ether_addr(sha))
+ goto out_free_skb;
+
+ /*
* Special case: We must set Frame Relay source Q.922 address
*/
if (dev_type == ARPHRD_DLCI)
--
2.47.3
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH net-next v3 1/4] arp: discard invalid sha addr (b/mcast ARP poison)
2026-02-04 22:11 ` [PATCH net-next v3 1/4] arp: discard invalid sha addr (b/mcast ARP poison) Marc Suñé
@ 2026-02-05 10:54 ` Vadim Fedorenko
0 siblings, 0 replies; 8+ messages in thread
From: Vadim Fedorenko @ 2026-02-05 10:54 UTC (permalink / raw)
To: Marc Suñé, kuba, willemdebruijn.kernel, pabeni; +Cc: netdev, dborkman
On 04/02/2026 22:11, Marc Suñé wrote:
> Prior to this commit, the ARP implementation accepted ARP req/replies
> with multicast (including broadcast) and null MAC addresses as Sender
> HW Address (SHA), and updated the ARP cache for that neighbour.
> Broadcast, multicast and null MAC addresses shall never be associated
> with a unicast or a multicast IPv4 address (see RFC1812, section 3.3.2).
>
> ARP poisioning with a broadcast MAC address and certain multicast
> addresses, especially when poisoning a Gateway IP, have some undesired
> implications compared to an ARP poisioning with a regular MAC (see
> Note1).
>
> Worth mentioning that if an attacker is able to ARP poison in
> a L2 segment, that in itself is probably a bigger security threat
> (Man-in-middle etc., see Note2).
>
> However, since these MACs should never be announced as SHA,
> discard/drop ARPs with SHA={b/mcast, null}, which prevents the
> broadcast/multicast ARP poisoning vector.
>
> Note1:
>
> After a successful broadcast/multicast ARP poisioning attack:
>
> 1. Unicast packets and refresh ("targeted") ARPs sent to or via
> the poisioned IP (e.g. the default GW) are flooded by
> bridges/switches. That is in absence of other security controls.
>
> Hardware swiches generally have rate-limits to prevent/mitigate
> broadcast storms, since ARPs are usually answered by the CPU.
> Legit unicast packets could be dropped (perf. degradation).
>
> Most modern NICs implement some form of L2 MAC filtering to early
> discard irrelevant packets. In contrast to an ARP poisoning
> attack with any other MAC, both unicast and ARP ("targeted")
> refresh packets are passed up to the Kernel networking stack
> (for all hosts in the L2 segment).
>
> 2. A single forged ARP packet (e.g. for the Gateway IP) can produce
> up to N "targeted" (to broadcast) ARPs, where N is the number of
> hosts in the L2 segment that have an ARP entry for that IP
> (e.g. GW), and some more traffic, since the real host will answer
> to targeted refresh ARPs with their (real) reply.
>
> This is a relatively low amount of traffic compared to 1).
>
> 3. An attacker could use this form of ARP poisoning to discover
> all hosts in a L2 segment in a very short period of time with
> one or few packets.
>
> By poisoning e.g. the default GW (likely multiple times, to
> avoid races with real gARPs from the GW), all hosts will eventually
> issue refresh "targeted" ARPs for the GW IP with the broadcast MAC
> address as destination. These packets will be flooded in the L2
> segment, revealing the presence of hosts to the attacker.
>
> For comparison:
> * Passive ARP monitoring: also stealthy, but can take a long
> time or not be possible at all in switches, as most refresh
> ARPs are targeted.
> * ARP req flooding: requires swiping the entire subnet. Noisy
> and easy to detect.
> * ICMP/L4 port scans: similar to the above.
>
> 4. In the unlikely case that hosts were to run with
> `/proc/sys/net/ipv4/conf/*/arp_accept=1` (unsafe, and disabled
> by default), poisoning with the broadcast MAC could be used to
> create significantly more broadcast traffic (low-volume
> amplification attack).
>
> An attacker could send M fake gARP with a number of IP addresses,
> where M is `/proc/sys/net/ipv4/neigh/*/gc_thresh3` (1024 by
> default). This would result in M x R ARPs, where R is the number
> of hosts in L2 segment with `arp_accept=1`, and likely other
> (real) ARP replies coming from the attacked host. This starts to
> get really relevant when R > 512, which is possible in large LANs
> but not very common.
>
> Note2:
>
> However, broadcast ARP poisoning might be subtle and difficult to
> spot. These ARP packets appear on the surface as regular broadcast
> ARP requests (unless ARP hdr is inspected), traffic continues to
> flow uninterrupted (unless broadcast rate-limit in switches kick-in)
> and, the next refresh ARP reply (from the GW) or any (valid) gARP
> from the GW, will restore the original MAC in the ARP table, making
> the traffic flow normally again.
>
> Signed-off-by: Marc Suñé <marcdevel@gmail.com>
Reviewed-by: Vadim Fedorenko <vadim.fedorenko@linux.dev>
^ permalink raw reply [flat|nested] 8+ messages in thread
* [PATCH net-next v3 2/4] selftests/net: add no ARP b/mcast,null poison test
2026-02-04 22:11 [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison) Marc Suñé
2026-02-04 22:11 ` [PATCH net-next v3 1/4] arp: discard invalid sha addr (b/mcast ARP poison) Marc Suñé
@ 2026-02-04 22:11 ` Marc Suñé
2026-02-04 22:12 ` [PATCH net-next v3 3/4] neigh: discard invalid lladdr (b/mcast poison) Marc Suñé
` (2 subsequent siblings)
4 siblings, 0 replies; 8+ messages in thread
From: Marc Suñé @ 2026-02-04 22:11 UTC (permalink / raw)
To: kuba, willemdebruijn.kernel, pabeni
Cc: netdev, dborkman, vadim.fedorenko, Marc Suñé
Add a selftest to test that ARP bcast/mcast/null poisioning checks
are never bypassed.
Signed-off-by: Marc Suñé <marcdevel@gmail.com>
---
tools/testing/selftests/net/Makefile | 1 +
.../net/arp_no_invalid_sha_poision.sh | 173 ++++++++++++++++++
2 files changed, 174 insertions(+)
create mode 100755 tools/testing/selftests/net/arp_no_invalid_sha_poision.sh
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 45c4ea381bc3..64bfbb29a427 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -11,6 +11,7 @@ TEST_PROGS := \
amt.sh \
arp_ndisc_evict_nocarrier.sh \
arp_ndisc_untracked_subnets.sh \
+ arp_no_invalid_sha_poision.sh \
bareudp.sh \
big_tcp.sh \
bind_bhash.sh \
diff --git a/tools/testing/selftests/net/arp_no_invalid_sha_poision.sh b/tools/testing/selftests/net/arp_no_invalid_sha_poision.sh
new file mode 100755
index 000000000000..755dd31212c8
--- /dev/null
+++ b/tools/testing/selftests/net/arp_no_invalid_sha_poision.sh
@@ -0,0 +1,173 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Tests that ARP announcements with Broadcast, Multicast or NULL mac are never
+# accepted
+#
+
+source lib.sh
+
+readonly V4_ADDR0="10.0.10.1"
+readonly V4_ADDR1="10.0.10.2"
+readonly BCAST_MAC="ff:ff:ff:ff:ff:ff"
+readonly MCAST_MAC="01:00:5e:00:00:00"
+readonly NULL_MAC="00:00:00:00:00:00"
+readonly VALID_MAC="02:01:02:03:04:05"
+readonly ARP_REQ="request"
+readonly ARP_REPLY="reply"
+ret=0
+veth1_mac=
+
+setup() {
+ setup_ns PEER_NS
+
+ ip link add name veth0 type veth peer name veth1
+ ip link set dev veth0 up
+ ip link set dev veth1 netns "${PEER_NS}"
+ ip netns exec "${PEER_NS}" ip link set dev veth1 up
+ ip addr add "${V4_ADDR0}"/24 dev veth0
+ ip netns exec "${PEER_NS}" ip addr add "${V4_ADDR1}"/24 dev veth1
+ ip netns exec "${PEER_NS}" ip route add default via "${V4_ADDR0}" dev veth1
+
+ # Raise ARP timers to avoid flakes due to refreshes
+ sysctl -w net.ipv4.neigh.veth0.base_reachable_time=3600 \
+ >/dev/null 2>&1
+ ip netns exec "${PEER_NS}" \
+ sysctl -w net.ipv4.neigh.veth1.gc_stale_time=3600 \
+ >/dev/null 2>&1
+ ip netns exec "${PEER_NS}" \
+ sysctl -w net.ipv4.neigh.veth1.base_reachable_time=3600 \
+ >/dev/null 2>&1
+
+ veth1_mac="$(ip netns exec "${PEER_NS}" ip -j link show veth1 | \
+ jq -r '.[0].address' )"
+}
+
+cleanup() {
+ ip neigh flush dev veth0
+ ip link del veth0
+ cleanup_ns "${PEER_NS}"
+}
+
+# Make sure ARP announcement with invalid MAC is never learnt
+run_no_arp_poisoning() {
+ local l2_dmac="${1}"
+ local tmac="${2}"
+ local op="${3}"
+
+ ret=0
+
+ ip netns exec "${PEER_NS}" ip neigh flush dev veth1 >/dev/null 2>&1
+ ip netns exec "${PEER_NS}" ping -c 1 "${V4_ADDR0}" >/dev/null 2>&1
+
+ # Poison with a valid MAC to ensure injection is working
+ mausezahn "veth0" -q -a "${VALID_MAC}" -b "${BCAST_MAC}" -t arp \
+ "${op}, sip=${V4_ADDR0}, tip=${V4_ADDR0}, smac=${VALID_MAC}, tmac=${VALID_MAC}"
+
+ neigh=$(ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}" | \
+ grep "${VALID_MAC}")
+ if [ "${neigh}" == "" ]; then
+ echo "ERROR: unable to ARP poision with a valid MAC ${VALID_MAC}"
+ ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}"
+ ret=1
+ return
+ fi
+
+ # Poison with tmac
+ mausezahn "veth0" -q -a "${VALID_MAC}" -b "${l2_dmac}" -t arp \
+ "${op}, sip=${V4_ADDR0}, tip=${V4_ADDR0}, smac=${tmac}, tmac=${tmac}"
+
+ neigh=$(ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}" | \
+ grep "${tmac}")
+ if [ "${neigh}" != "" ]; then
+ echo "ERROR: ARP entry learnt for ${tmac} announcement."
+ ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}"
+ ret=1
+ return
+ fi
+}
+
+print_test_result() {
+ local msg="${1}"
+ local rc="${2}"
+
+ if [ "${rc}" == 0 ]; then
+ printf "TEST: %-60s [ OK ]" "${msg}"
+ else
+ printf "TEST: %-60s [ FAIL ]" "${msg}"
+ fi
+}
+
+run_all_tests() {
+ local results
+
+ setup
+
+ ## ARP
+ # Broadcast gARPs
+ msg="1.1 ARP no poisoning dmac=bcast reply sha=bcast"
+ run_no_arp_poisoning "${BCAST_MAC}" "${BCAST_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.2 ARP no poisoning dmac=bcast reply sha=null"
+ run_no_arp_poisoning "${BCAST_MAC}" "${NULL_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.3 ARP no poisoning dmac=bcast req sha=bcast"
+ run_no_arp_poisoning "${BCAST_MAC}" "${BCAST_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.4 ARP no poisoning dmac=bcast req sha=null"
+ run_no_arp_poisoning "${BCAST_MAC}" "${NULL_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.5 ARP no poisoning dmac=bcast req sha=mcast"
+ run_no_arp_poisoning "${BCAST_MAC}" "${MCAST_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.6 ARP no poisoning dmac=bcast reply sha=mcast"
+ run_no_arp_poisoning "${BCAST_MAC}" "${MCAST_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ # Targeted gARPs
+ msg="1.7 ARP no poisoning dmac=veth0 reply sha=bcast"
+ run_no_arp_poisoning "${veth1_mac}" "${BCAST_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.8 ARP no poisoning dmac=veth0 reply sha=null"
+ run_no_arp_poisoning "${veth1_mac}" "${NULL_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.9 ARP no poisoning dmac=veth0 req sha=bcast"
+ run_no_arp_poisoning "${veth1_mac}" "${BCAST_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.10 ARP no poisoning dmac=veth0 req sha=null"
+ run_no_arp_poisoning "${veth1_mac}" "${NULL_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.11 ARP no poisoning dmac=veth0 req sha=mcast"
+ run_no_arp_poisoning "${veth1_mac}" "${MCAST_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.12 ARP no poisoning dmac=veth0 reply sha=mcast"
+ run_no_arp_poisoning "${veth1_mac}" "${MCAST_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ cleanup
+
+ printf '%b' "${results}"
+}
+
+if [ "$(id -u)" -ne 0 ];then
+ echo "SKIP: Need root privileges"
+ exit "${ksft_skip}"
+fi
+
+if [ ! -x "$(command -v ip)" ]; then
+ echo "SKIP: Could not run test without ip tool"
+ exit "${ksft_skip}"
+fi
+
+run_all_tests
+exit "${ret}"
--
2.47.3
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH net-next v3 3/4] neigh: discard invalid lladdr (b/mcast poison)
2026-02-04 22:11 [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison) Marc Suñé
2026-02-04 22:11 ` [PATCH net-next v3 1/4] arp: discard invalid sha addr (b/mcast ARP poison) Marc Suñé
2026-02-04 22:11 ` [PATCH net-next v3 2/4] selftests/net: add no ARP b/mcast,null poison test Marc Suñé
@ 2026-02-04 22:12 ` Marc Suñé
2026-02-04 22:12 ` [PATCH net-next v3 4/4] selftests/net: add no NDP b/mcast,null poison test Marc Suñé
2026-02-06 2:31 ` [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison) Jakub Kicinski
4 siblings, 0 replies; 8+ messages in thread
From: Marc Suñé @ 2026-02-04 22:12 UTC (permalink / raw)
To: kuba, willemdebruijn.kernel, pabeni
Cc: netdev, dborkman, vadim.fedorenko, Marc Suñé
Prior to this commit, the NDP implementation accepted NDP NS/NA with
the broadcast, multicast and null addresses as src/dst lladdr, and
updated the neighbour cache for that host.
Broadcast, multicast and null MAC addresses shall never be associated
with a unicast or a multicast IPv6 address (see RFC1812, section 3.3.2).
NDP poisioning with a broadcast MAC and certain multicast MAC addresses,
especially when poisoning a Gateway IP, have some undesired implications
compared to an NDP poisioning with a regular MAC (see ARP bcast poison
commit for more details).
Since these MACs should never be announced, discard/drop NDP with
lladdr={bcast, null}, which prevents the broadcast/multicast NDP
poisoning vector.
Signed-off-by: Marc Suñé <marcdevel@gmail.com>
---
net/ipv6/ndisc.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/net/ipv6/ndisc.c b/net/ipv6/ndisc.c
index f6a5d8c73af9..8fe215505869 100644
--- a/net/ipv6/ndisc.c
+++ b/net/ipv6/ndisc.c
@@ -830,6 +830,14 @@ static enum skb_drop_reason ndisc_recv_ns(struct sk_buff *skb)
return reason;
}
+ /*
+ * Broadcast/Multicast and zero MAC addresses should
+ * never be announced and accepted as llsrc address (prevent
+ * NDP B/MCAST MAC poisoning attack).
+ */
+ if (dev->type == ARPHRD_ETHER && !is_valid_ether_addr(lladdr))
+ return reason;
+
/* RFC2461 7.1.1:
* If the IP source address is the unspecified address,
* there MUST NOT be source link-layer address option
@@ -1033,6 +1041,14 @@ static enum skb_drop_reason ndisc_recv_na(struct sk_buff *skb)
net_dbg_ratelimited("NA: invalid link-layer address length\n");
return reason;
}
+
+ /*
+ * Broadcast/Multicast and zero MAC addresses should
+ * never be announced and accepted as lltgt address (prevent
+ * NDP B/MCAST MAC poisoning attack).
+ */
+ if (dev->type == ARPHRD_ETHER && !is_valid_ether_addr(lladdr))
+ return reason;
}
ifp = ipv6_get_ifaddr(dev_net(dev), &msg->target, dev, 1);
if (ifp) {
--
2.47.3
^ permalink raw reply related [flat|nested] 8+ messages in thread* [PATCH net-next v3 4/4] selftests/net: add no NDP b/mcast,null poison test
2026-02-04 22:11 [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison) Marc Suñé
` (2 preceding siblings ...)
2026-02-04 22:12 ` [PATCH net-next v3 3/4] neigh: discard invalid lladdr (b/mcast poison) Marc Suñé
@ 2026-02-04 22:12 ` Marc Suñé
2026-02-06 2:31 ` [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison) Jakub Kicinski
4 siblings, 0 replies; 8+ messages in thread
From: Marc Suñé @ 2026-02-04 22:12 UTC (permalink / raw)
To: kuba, willemdebruijn.kernel, pabeni
Cc: netdev, dborkman, vadim.fedorenko, Marc Suñé
Add a selftest to test that NDP bcast/mcast/null poisioning checks are
never bypassed.
Signed-off-by: Marc Suñé <marcdevel@gmail.com>
---
tools/testing/selftests/net/.gitignore | 1 +
tools/testing/selftests/net/Makefile | 2 +
.../net/arp_ndisc_no_invalid_sha_poison.sh | 368 ++++++++++++++++++
.../net/arp_no_invalid_sha_poision.sh | 173 --------
tools/testing/selftests/net/ndisc_send.c | 198 ++++++++++
5 files changed, 569 insertions(+), 173 deletions(-)
create mode 100755 tools/testing/selftests/net/arp_ndisc_no_invalid_sha_poison.sh
delete mode 100755 tools/testing/selftests/net/arp_no_invalid_sha_poision.sh
create mode 100644 tools/testing/selftests/net/ndisc_send.c
diff --git a/tools/testing/selftests/net/.gitignore b/tools/testing/selftests/net/.gitignore
index 6930fe926c58..ffe522e36d39 100644
--- a/tools/testing/selftests/net/.gitignore
+++ b/tools/testing/selftests/net/.gitignore
@@ -17,6 +17,7 @@ ipv6_flowlabel_mgr
ipv6_fragmentation
log.txt
msg_zerocopy
+ndisc_send
netlink-dumps
nettest
proc_net_pktgen
diff --git a/tools/testing/selftests/net/Makefile b/tools/testing/selftests/net/Makefile
index 64bfbb29a427..5ccea6fc35a8 100644
--- a/tools/testing/selftests/net/Makefile
+++ b/tools/testing/selftests/net/Makefile
@@ -10,6 +10,7 @@ TEST_PROGS := \
altnames.sh \
amt.sh \
arp_ndisc_evict_nocarrier.sh \
+ arp_ndisc_no_invalid_sha_poison.sh \
arp_ndisc_untracked_subnets.sh \
arp_no_invalid_sha_poision.sh \
bareudp.sh \
@@ -169,6 +170,7 @@ TEST_GEN_PROGS := \
bind_wildcard \
epoll_busy_poll \
ipv6_fragmentation \
+ ndisc_send \
proc_net_pktgen \
reuseaddr_conflict \
reuseport_bpf \
diff --git a/tools/testing/selftests/net/arp_ndisc_no_invalid_sha_poison.sh b/tools/testing/selftests/net/arp_ndisc_no_invalid_sha_poison.sh
new file mode 100755
index 000000000000..ad91eac18c89
--- /dev/null
+++ b/tools/testing/selftests/net/arp_ndisc_no_invalid_sha_poison.sh
@@ -0,0 +1,368 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+#
+# Tests that ARP announcements with Broadcast or NULL mac are never
+# accepted
+#
+
+source lib.sh
+
+readonly V4_ADDR0="10.0.10.1"
+readonly V6_ADDR0="fd00:1::1"
+readonly V4_ADDR1="10.0.10.2"
+readonly V6_ADDR1="fd00:1::2"
+readonly V6_ALL_NODES="ff02::1"
+readonly V6_SOL_NODE1="ff02::1:ff00:0002"
+readonly BCAST_MAC="ff:ff:ff:ff:ff:ff"
+readonly MCAST_MAC="01:00:5e:00:00:00"
+readonly NULL_MAC="00:00:00:00:00:00"
+readonly VALID_MAC="02:01:02:03:04:05"
+readonly V6_ALL_NODE_MAC="33:33:FF:00:00:01"
+readonly V6_SOL_NODE_MAC1="33:33:FF:00:00:02"
+readonly NS=135
+readonly NA=136
+readonly ARP_REQ=request
+readonly ARP_REPLY=reply
+ret=0
+veth0_ifindex=0
+veth1_mac=
+
+setup() {
+ setup_ns PEER_NS
+
+ ip link add name veth0 type veth peer name veth1
+ ip link set dev veth0 up
+ ip link set dev veth1 netns "${PEER_NS}"
+ ip netns exec "${PEER_NS}" ip link set dev veth1 up
+ ip addr add "${V4_ADDR0}"/24 dev veth0
+ ip addr add "${V6_ADDR0}"/64 dev veth0
+ ip netns exec "${PEER_NS}" ip addr add "${V4_ADDR1}"/24 dev veth1
+ ip netns exec "${PEER_NS}" ip route add default via "${V4_ADDR0}" dev veth1
+
+ ip netns exec "${PEER_NS}" ip addr add "${V6_ADDR1}"/64 dev veth1
+ ip netns exec "${PEER_NS}" ip route add default via "${V6_ADDR0}" dev veth1
+
+ # Raise ARP timers to avoid flakes due to refreshes
+ sysctl -w net.ipv4.neigh.veth0.base_reachable_time=3600 \
+ >/dev/null 2>&1
+ ip netns exec "${PEER_NS}" \
+ sysctl -w net.ipv4.neigh.veth1.gc_stale_time=3600 \
+ >/dev/null 2>&1
+ ip netns exec "${PEER_NS}" \
+ sysctl -w net.ipv4.neigh.veth1.base_reachable_time=3600 \
+ >/dev/null 2>&1
+
+ veth0_ifindex=$(ip -j link show veth0 | jq -r '.[0].ifindex')
+ veth1_mac="$(ip netns exec "${PEER_NS}" ip -j link show veth1 | \
+ jq -r '.[0].address' )"
+}
+
+cleanup() {
+ ip neigh flush dev veth0
+ ip link del veth0
+ cleanup_ns "${PEER_NS}"
+}
+
+# Make sure ARP announcement with invalid MAC is never learnt
+run_no_arp_poisoning() {
+ local l2_dmac="${1}"
+ local tmac="${2}"
+ local op="${3}"
+
+ ret=0
+
+ ip netns exec "${PEER_NS}" ip neigh flush dev veth1 >/dev/null 2>&1
+ ip netns exec "${PEER_NS}" ping -c 1 "${V4_ADDR0}" >/dev/null 2>&1
+
+ # Poison with a valid MAC to ensure injection is working
+ mausezahn "veth0" -q -a "${VALID_MAC}" -b "${BCAST_MAC}" -t arp \
+ "${op}, sip=${V4_ADDR0}, tip=${V4_ADDR0}, smac=${VALID_MAC}, tmac=${VALID_MAC}"
+
+ neigh=$(ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}" | \
+ grep "${VALID_MAC}")
+ if [ "${neigh}" == "" ]; then
+ echo "ERROR: unable to ARP poision with a valid MAC ${VALID_MAC}"
+ ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}"
+ ret=1
+ return
+ fi
+
+ # Poison with tmac
+ mausezahn "veth0" -q -a "${VALID_MAC}" -b "${l2_dmac}" -t arp \
+ "${op}, sip=${V4_ADDR0}, tip=${V4_ADDR0}, smac=${tmac}, tmac=${tmac}"
+
+
+ neigh=$(ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}" | \
+ grep "${tmac}")
+ if [ "${neigh}" != "" ]; then
+ echo "ERROR: ARP entry learnt for ${tmac} announcement."
+ ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}"
+ ret=1
+ return
+ fi
+}
+
+# Make sure NDP announcement with invalid MAC is never learnt
+run_no_ndp_poisoning() {
+ local l2_dmac="${1}"
+ local dst_ip="${2}"
+ local op="${3}"
+ local tip="${V6_ADDR0}"
+ local tmac="${4}"
+
+ if [ "${op}" == "${NS}" ]; then
+ tip="${V6_ADDR1}"
+ fi
+
+ ret=0
+
+ ip netns exec "${PEER_NS}" ip -6 neigh flush dev veth1 >/dev/null 2>&1
+ ip netns exec "${PEER_NS}" ping -c 1 "${V6_ADDR0}" >/dev/null 2>&1
+
+ # Poison with a valid MAC to ensure injection is working
+ ./ndisc_send "${veth0_ifindex}" "${l2_dmac}" "${VALID_MAC}" "${dst_ip}" \
+ "${V6_ADDR0}" "${tip}" "${op}" "${VALID_MAC}"
+ neigh=$(ip netns exec "${PEER_NS}" ip neigh show "${V6_ADDR0}" | \
+ grep "${VALID_MAC}")
+ if [ "${neigh}" == "" ]; then
+ echo "ERROR: unable to NDP poision with a valid MAC ${VALID_MAC}"
+ ip netns exec "${PEER_NS}" ip neigh show "${V6_ADDR0}"
+ ret=1
+ return
+ fi
+
+ # Poison with tmac
+ ./ndisc_send "${veth0_ifindex}" "${l2_dmac}" "${VALID_MAC}" "${dst_ip}" \
+ "${V6_ADDR0}" "${tip}" "${op}" "${tmac}"
+ neigh=$(ip netns exec "${PEER_NS}" ip neigh show "${V6_ADDR0}" | \
+ grep "${tmac}")
+ if [ "${neigh}" != "" ]; then
+ echo "ERROR: NDP entry learnt for ${tmac} announcement."
+ ip netns exec "${PEER_NS}" ip neigh show "${V6_ADDR0}"
+ ret=1
+ return
+ fi
+}
+
+print_test_result() {
+ local msg="${1}"
+ local rc="${2}"
+
+ if [ "${rc}" == 0 ]; then
+ printf "TEST: %-60s [ OK ]" "${msg}"
+ else
+ printf "TEST: %-60s [ FAIL ]" "${msg}"
+ fi
+}
+
+run_all_tests() {
+ local results
+
+ setup
+
+ ## ARP
+ # Broadcast gARPs
+ msg="1.1 ARP no poisoning dmac=bcast reply sha=bcast"
+ run_no_arp_poisoning "${BCAST_MAC}" "${BCAST_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.2 ARP no poisoning dmac=bcast reply sha=null"
+ run_no_arp_poisoning "${BCAST_MAC}" "${NULL_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.3 ARP no poisoning dmac=bcast req sha=bcast"
+ run_no_arp_poisoning "${BCAST_MAC}" "${BCAST_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.4 ARP no poisoning dmac=bcast req sha=null"
+ run_no_arp_poisoning "${BCAST_MAC}" "${NULL_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.5 ARP no poisoning dmac=bcast req sha=mcast"
+ run_no_arp_poisoning "${BCAST_MAC}" "${MCAST_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.6 ARP no poisoning dmac=bcast reply sha=mcast"
+ run_no_arp_poisoning "${BCAST_MAC}" "${MCAST_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ # Targeted gARPs
+ msg="1.7 ARP no poisoning dmac=veth0 reply sha=bcast"
+ run_no_arp_poisoning "${veth1_mac}" "${BCAST_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.8 ARP no poisoning dmac=veth0 reply sha=null"
+ run_no_arp_poisoning "${veth1_mac}" "${NULL_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.9 ARP no poisoning dmac=veth0 req sha=bcast"
+ run_no_arp_poisoning "${veth1_mac}" "${BCAST_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.10 ARP no poisoning dmac=veth0 req sha=null"
+ run_no_arp_poisoning "${veth1_mac}" "${NULL_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.11 ARP no poisoning dmac=veth0 req sha=mcast"
+ run_no_arp_poisoning "${veth1_mac}" "${MCAST_MAC}" "${ARP_REQ}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="1.12 ARP no poisoning dmac=veth0 reply sha=mcast"
+ run_no_arp_poisoning "${veth1_mac}" "${MCAST_MAC}" "${ARP_REPLY}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ ### NDP
+ ## NA
+ # Broadcast / All node MAC, all-node IP announcements
+ msg="2.1 NDP no poisoning dmac=bcast all_nodes na lladdr=bcast"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ALL_NODES}" "${NA}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.2 NDP no poisoning dmac=bcast all_nodes na lladdr=null"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ALL_NODES}" "${NA}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.3 NDP no poisoning dmac=allnode all_nodes na lladdr=bcast"
+ run_no_ndp_poisoning "${V6_ALL_NODE_MAC}" "${V6_ALL_NODES}" "${NA}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.4 NDP no poisoning dmac=allnode all_nodes na lladdr=null"
+ run_no_ndp_poisoning "${V6_ALL_NODE_MAC}" "${V6_ALL_NODES}" "${NA}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.5 NDP no poisoning dmac=bcast all_nodes na lladdr=bcast"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ALL_NODES}" "${NA}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.6 NDP no poisoning dmac=bcast all_nodes na lladdr=null"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ALL_NODES}" "${NA}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.7 NDP no poisoning dmac=allnode all_nodes na lladdr=bcast"
+ run_no_ndp_poisoning "${V6_ALL_NODE_MAC}" "${V6_ALL_NODES}" "${NA}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.8 NDP no poisoning dmac=allnode all_nodes na lladdr=null"
+ run_no_ndp_poisoning "${V6_ALL_NODE_MAC}" "${V6_ALL_NODES}" "${NA}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ # Broadcast / All node MAC, Targeted IP announce
+ msg="2.9 NDP no poisoning dmac=bcast targeted na lladdr=bcast"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ADDR1}" "${NA}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.10 NDP no poisoning dmac=bcast targeted na lladdr=null"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ADDR1}" "${NA}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.11 NDP no poisoning dmac=allnode targeted na lladdr=bcast"
+ run_no_ndp_poisoning "${V6_ALL_NODE_MAC}" "${V6_ADDR1}" "${NA}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.12 NDP no poisoning dmac=allnode targeted na lladdr=null"
+ run_no_ndp_poisoning "${V6_ALL_NODE_MAC}" "${V6_ADDR1}" "${NA}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.13 NDP no poisoning dmac=bcast targeted na lladdr=bcast"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ADDR1}" "${NA}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.14 NDP no poisoning dmac=bcast targeted na lladdr=null"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ADDR1}" "${NA}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.15 NDP no poisoning dmac=allnode targeted na lladdr=bcast"
+ run_no_ndp_poisoning "${V6_ALL_NODE_MAC}" "${V6_ADDR1}" "${NA}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.16 NDP no poisoning dmac=allnode targeted na lladdr=null"
+ run_no_ndp_poisoning "${V6_ALL_NODE_MAC}" "${V6_ADDR1}" "${NA}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ # Targeted MAC, Targeted IP announce
+ msg="2.17 NDP no poisoning dmac=veth1 targeted na lladdr=bcast"
+ run_no_ndp_poisoning "${veth1_mac}" "${V6_ADDR1}" "${NA}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.18 NDP no poisoning dmac=veth1 targeted na lladdr=null"
+ run_no_ndp_poisoning "${veth1_mac}" "${V6_ADDR1}" "${NA}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ # Poison with MCAST mac
+ msg="2.19 NDP no poisoning dmac=allnode all_nodes na lladdr=mcast"
+ run_no_ndp_poisoning "${V6_ALL_NODE_MAC}" "${V6_ALL_NODES}" "${NA}" "${MCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+ msg="2.20 NDP no poisoning dmac=veth1 targeted na lladdr=mcast"
+ run_no_ndp_poisoning "${veth1_mac}" "${V6_ADDR1}" "${NA}" "${MCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ ## NS
+ # Broadcast / SolNode node MAC, SolNode IP solic
+ msg="2.21 NDP no poisoning dmac=bcast solnode ns lladdr=bcast"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_SOL_NODE1}" "${NS}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.22 NDP no poisoning dmac=bcast solnode ns lladdr=null"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_SOL_NODE1}" "${NS}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.23 NDP no poisoning dmac=solnode solnode ns lladdr=bcast"
+ run_no_ndp_poisoning "${V6_SOL_NODE_MAC1}" "${V6_SOL_NODE1}" "${NS}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.24 NDP no poisoning dmac=solnode solnode ns lladdr=null"
+ run_no_ndp_poisoning "${V6_SOL_NODE_MAC1}" "${V6_SOL_NODE1}" "${NS}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ # Broadcast / SolNode node MAC, target IP solic
+ msg="2.25 NDP no poisoning dmac=bcast target ns lladdr=bcast"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ADDR1}" "${NS}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.26 NDP no poisoning dmac=bcast target ns lladdr=null"
+ run_no_ndp_poisoning "${BCAST_MAC}" "${V6_ADDR1}" "${NS}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.27 NDP no poisoning dmac=solnode target ns lladdr=bcast"
+ run_no_ndp_poisoning "${V6_SOL_NODE_MAC1}" "${V6_ADDR1}" "${NS}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.28 NDP no poisoning dmac=solnode target ns lladdr=null"
+ run_no_ndp_poisoning "${V6_SOL_NODE_MAC1}" "${V6_ADDR1}" "${NS}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ # Targeted MAC, Targeted IP solic
+ msg="2.29 NDP no poisoning dmac=veth1 target ns lladdr=bcast"
+ run_no_ndp_poisoning "${veth1_mac}" "${V6_ADDR1}" "${NS}" "${BCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.30 NDP no poisoning dmac=veth1 target ns lladdr=null"
+ run_no_ndp_poisoning "${veth1_mac}" "${V6_ADDR1}" "${NS}" "${NULL_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ # Poison with MCAST mac
+ msg="2.31 NDP no poisoning dmac=solnode solnode ns lladdr=mcast"
+ run_no_ndp_poisoning "${V6_SOL_NODE_MAC1}" "${V6_SOL_NODE1}" "${NS}" "${MCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ msg="2.32 NDP no poisoning dmac=veth1 target ns lladdr=mcast"
+ run_no_ndp_poisoning "${veth1_mac}" "${V6_ADDR1}" "${NS}" "${MCAST_MAC}"
+ results+="$(print_test_result "${msg}" "${ret}")\n"
+
+ cleanup
+
+ printf '%b' "${results}"
+}
+
+if [ "$(id -u)" -ne 0 ];then
+ echo "SKIP: Need root privileges"
+ exit "${ksft_skip}"
+fi
+
+if [ ! -x "$(command -v ip)" ]; then
+ echo "SKIP: Could not run test without ip tool"
+ exit "${ksft_skip}"
+fi
+
+run_all_tests
+exit "${ret}"
diff --git a/tools/testing/selftests/net/arp_no_invalid_sha_poision.sh b/tools/testing/selftests/net/arp_no_invalid_sha_poision.sh
deleted file mode 100755
index 755dd31212c8..000000000000
--- a/tools/testing/selftests/net/arp_no_invalid_sha_poision.sh
+++ /dev/null
@@ -1,173 +0,0 @@
-#!/bin/bash
-# SPDX-License-Identifier: GPL-2.0
-#
-# Tests that ARP announcements with Broadcast, Multicast or NULL mac are never
-# accepted
-#
-
-source lib.sh
-
-readonly V4_ADDR0="10.0.10.1"
-readonly V4_ADDR1="10.0.10.2"
-readonly BCAST_MAC="ff:ff:ff:ff:ff:ff"
-readonly MCAST_MAC="01:00:5e:00:00:00"
-readonly NULL_MAC="00:00:00:00:00:00"
-readonly VALID_MAC="02:01:02:03:04:05"
-readonly ARP_REQ="request"
-readonly ARP_REPLY="reply"
-ret=0
-veth1_mac=
-
-setup() {
- setup_ns PEER_NS
-
- ip link add name veth0 type veth peer name veth1
- ip link set dev veth0 up
- ip link set dev veth1 netns "${PEER_NS}"
- ip netns exec "${PEER_NS}" ip link set dev veth1 up
- ip addr add "${V4_ADDR0}"/24 dev veth0
- ip netns exec "${PEER_NS}" ip addr add "${V4_ADDR1}"/24 dev veth1
- ip netns exec "${PEER_NS}" ip route add default via "${V4_ADDR0}" dev veth1
-
- # Raise ARP timers to avoid flakes due to refreshes
- sysctl -w net.ipv4.neigh.veth0.base_reachable_time=3600 \
- >/dev/null 2>&1
- ip netns exec "${PEER_NS}" \
- sysctl -w net.ipv4.neigh.veth1.gc_stale_time=3600 \
- >/dev/null 2>&1
- ip netns exec "${PEER_NS}" \
- sysctl -w net.ipv4.neigh.veth1.base_reachable_time=3600 \
- >/dev/null 2>&1
-
- veth1_mac="$(ip netns exec "${PEER_NS}" ip -j link show veth1 | \
- jq -r '.[0].address' )"
-}
-
-cleanup() {
- ip neigh flush dev veth0
- ip link del veth0
- cleanup_ns "${PEER_NS}"
-}
-
-# Make sure ARP announcement with invalid MAC is never learnt
-run_no_arp_poisoning() {
- local l2_dmac="${1}"
- local tmac="${2}"
- local op="${3}"
-
- ret=0
-
- ip netns exec "${PEER_NS}" ip neigh flush dev veth1 >/dev/null 2>&1
- ip netns exec "${PEER_NS}" ping -c 1 "${V4_ADDR0}" >/dev/null 2>&1
-
- # Poison with a valid MAC to ensure injection is working
- mausezahn "veth0" -q -a "${VALID_MAC}" -b "${BCAST_MAC}" -t arp \
- "${op}, sip=${V4_ADDR0}, tip=${V4_ADDR0}, smac=${VALID_MAC}, tmac=${VALID_MAC}"
-
- neigh=$(ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}" | \
- grep "${VALID_MAC}")
- if [ "${neigh}" == "" ]; then
- echo "ERROR: unable to ARP poision with a valid MAC ${VALID_MAC}"
- ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}"
- ret=1
- return
- fi
-
- # Poison with tmac
- mausezahn "veth0" -q -a "${VALID_MAC}" -b "${l2_dmac}" -t arp \
- "${op}, sip=${V4_ADDR0}, tip=${V4_ADDR0}, smac=${tmac}, tmac=${tmac}"
-
- neigh=$(ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}" | \
- grep "${tmac}")
- if [ "${neigh}" != "" ]; then
- echo "ERROR: ARP entry learnt for ${tmac} announcement."
- ip netns exec "${PEER_NS}" ip neigh show "${V4_ADDR0}"
- ret=1
- return
- fi
-}
-
-print_test_result() {
- local msg="${1}"
- local rc="${2}"
-
- if [ "${rc}" == 0 ]; then
- printf "TEST: %-60s [ OK ]" "${msg}"
- else
- printf "TEST: %-60s [ FAIL ]" "${msg}"
- fi
-}
-
-run_all_tests() {
- local results
-
- setup
-
- ## ARP
- # Broadcast gARPs
- msg="1.1 ARP no poisoning dmac=bcast reply sha=bcast"
- run_no_arp_poisoning "${BCAST_MAC}" "${BCAST_MAC}" "${ARP_REPLY}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.2 ARP no poisoning dmac=bcast reply sha=null"
- run_no_arp_poisoning "${BCAST_MAC}" "${NULL_MAC}" "${ARP_REPLY}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.3 ARP no poisoning dmac=bcast req sha=bcast"
- run_no_arp_poisoning "${BCAST_MAC}" "${BCAST_MAC}" "${ARP_REQ}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.4 ARP no poisoning dmac=bcast req sha=null"
- run_no_arp_poisoning "${BCAST_MAC}" "${NULL_MAC}" "${ARP_REQ}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.5 ARP no poisoning dmac=bcast req sha=mcast"
- run_no_arp_poisoning "${BCAST_MAC}" "${MCAST_MAC}" "${ARP_REQ}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.6 ARP no poisoning dmac=bcast reply sha=mcast"
- run_no_arp_poisoning "${BCAST_MAC}" "${MCAST_MAC}" "${ARP_REPLY}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- # Targeted gARPs
- msg="1.7 ARP no poisoning dmac=veth0 reply sha=bcast"
- run_no_arp_poisoning "${veth1_mac}" "${BCAST_MAC}" "${ARP_REPLY}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.8 ARP no poisoning dmac=veth0 reply sha=null"
- run_no_arp_poisoning "${veth1_mac}" "${NULL_MAC}" "${ARP_REPLY}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.9 ARP no poisoning dmac=veth0 req sha=bcast"
- run_no_arp_poisoning "${veth1_mac}" "${BCAST_MAC}" "${ARP_REQ}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.10 ARP no poisoning dmac=veth0 req sha=null"
- run_no_arp_poisoning "${veth1_mac}" "${NULL_MAC}" "${ARP_REQ}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.11 ARP no poisoning dmac=veth0 req sha=mcast"
- run_no_arp_poisoning "${veth1_mac}" "${MCAST_MAC}" "${ARP_REQ}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- msg="1.12 ARP no poisoning dmac=veth0 reply sha=mcast"
- run_no_arp_poisoning "${veth1_mac}" "${MCAST_MAC}" "${ARP_REPLY}"
- results+="$(print_test_result "${msg}" "${ret}")\n"
-
- cleanup
-
- printf '%b' "${results}"
-}
-
-if [ "$(id -u)" -ne 0 ];then
- echo "SKIP: Need root privileges"
- exit "${ksft_skip}"
-fi
-
-if [ ! -x "$(command -v ip)" ]; then
- echo "SKIP: Could not run test without ip tool"
- exit "${ksft_skip}"
-fi
-
-run_all_tests
-exit "${ret}"
diff --git a/tools/testing/selftests/net/ndisc_send.c b/tools/testing/selftests/net/ndisc_send.c
new file mode 100644
index 000000000000..4f226221d079
--- /dev/null
+++ b/tools/testing/selftests/net/ndisc_send.c
@@ -0,0 +1,198 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <sys/socket.h>
+#include <inttypes.h>
+#include <netinet/ether.h>
+#include <arpa/inet.h>
+
+#include <linux/if_packet.h>
+#include <linux/if_ether.h>
+#include <linux/ipv6.h>
+#include <linux/icmpv6.h>
+
+#define ICMPV6_ND_NS 135
+#define ICMPV6_ND_NA 136
+#define ICMPV6_ND_SLLADR 1
+#define ICMPV6_ND_TLLADR 2
+
+#ifndef __noinline
+#define __noinline __attribute__((noinline))
+#endif
+#ifndef __packed
+#define __packed __attribute__((packed))
+#endif
+
+struct icmp6_pseudohdr {
+ struct in6_addr saddr;
+ struct in6_addr daddr;
+ uint32_t plen;
+ uint8_t zero[3];
+ uint8_t next;
+};
+
+struct ndisc_pkt {
+ struct ethhdr eth;
+ struct ipv6hdr ip6;
+ struct ndp_hdrs {
+ struct icmp6hdr hdr;
+ struct in6_addr target;
+
+ uint8_t opt_type;
+ uint8_t opt_len;
+ uint8_t opt_mac[ETH_ALEN];
+ } __packed ndp;
+} __packed;
+
+__noinline uint32_t csum_add(void *buf, int len, uint32_t sum)
+{
+ uint16_t *p = (uint16_t *)buf;
+
+ while (len > 1) {
+ sum += *p++;
+ len -= 2;
+ }
+
+ if (len)
+ sum += *(uint8_t *)p;
+
+ return sum;
+}
+
+static uint16_t csum_fold(uint32_t sum)
+{
+ return ~((sum & 0xffff) + (sum >> 16)) ? : 0xffff;
+}
+
+int parse_opts(int argc, char **argv, int *ifindex, struct ndisc_pkt *pkt)
+{
+ struct ether_addr *mac;
+ uint16_t op;
+ struct icmp6_pseudohdr ph = {0};
+ uint32_t sum = 0;
+
+ if (argc != 9) {
+ fprintf(stderr, "Usage: %s <iface> <mac_dst> <mac_src> <dst_ip> <src_ip> <target_ip> <op> <lladr>\n",
+ argv[0]);
+ return -1;
+ }
+
+ *ifindex = atoi(argv[1]);
+ mac = ether_aton(argv[2]);
+ if (!mac) {
+ fprintf(stderr, "Unable to parse mac_dst from '%s'\n", argv[1]);
+ return -1;
+ }
+
+ /* Ethernet */
+ memcpy(pkt->eth.h_dest, mac, ETH_ALEN);
+ mac = ether_aton(argv[3]);
+ if (!mac) {
+ fprintf(stderr, "Unable to parse mac_src from '%s'\n", argv[2]);
+ return -1;
+ }
+ memcpy(pkt->eth.h_source, mac, ETH_ALEN);
+ pkt->eth.h_proto = htons(ETH_P_IPV6);
+
+ /* IPv6 */
+ pkt->ip6.version = 6;
+ pkt->ip6.nexthdr = IPPROTO_ICMPV6;
+ pkt->ip6.hop_limit = 255;
+
+ if (inet_pton(AF_INET6, argv[4], &pkt->ip6.daddr) != 1) {
+ fprintf(stderr, "Unable to parse src_ip from '%s'\n", argv[4]);
+ return -1;
+ }
+ if (inet_pton(AF_INET6, argv[5], &pkt->ip6.saddr) != 1) {
+ fprintf(stderr, "Unable to parse src_ip from '%s'\n", argv[5]);
+ return -1;
+ }
+
+ /* ICMPv6 */
+ op = atoi(argv[7]);
+ if (op != ICMPV6_ND_NS && op != ICMPV6_ND_NA) {
+ fprintf(stderr, "Invalid ICMPv6 op %d\n", op);
+ return -1;
+ }
+
+ pkt->ndp.hdr.icmp6_type = op;
+ pkt->ndp.hdr.icmp6_code = 0;
+
+ if (inet_pton(AF_INET6, argv[6], &pkt->ndp.target) != 1) {
+ fprintf(stderr, "Unable to parse target_ip from '%s'\n",
+ argv[6]);
+ return -1;
+ }
+
+ /* Target/Source Link-Layer Address */
+ if (op == ICMPV6_ND_NS) {
+ pkt->ndp.opt_type = ICMPV6_ND_SLLADR;
+ } else {
+ pkt->ndp.opt_type = ICMPV6_ND_TLLADR;
+ pkt->ndp.hdr.icmp6_override = 1;
+ }
+ pkt->ndp.opt_len = 1;
+
+ mac = ether_aton(argv[8]);
+ if (!mac) {
+ fprintf(stderr, "Invalid lladdr %s\n", argv[8]);
+ return -1;
+ }
+
+ memcpy(pkt->ndp.opt_mac, mac, ETH_ALEN);
+
+ pkt->ip6.payload_len = htons(sizeof(pkt->ndp));
+
+ /* Pseudoheader */
+ ph.saddr = pkt->ip6.saddr;
+ ph.daddr = pkt->ip6.daddr;
+ ph.plen = htonl(sizeof(pkt->ndp));
+ ph.next = IPPROTO_ICMPV6;
+
+ sum = csum_add(&ph, sizeof(ph), 0);
+ sum = csum_add(&pkt->ndp, sizeof(pkt->ndp), sum);
+
+ pkt->ndp.hdr.icmp6_cksum = csum_fold(sum);
+
+ return 0;
+}
+
+int main(int argc, char **argv)
+{
+ int rc, fd;
+ struct sockaddr_ll bind_addr = {0};
+ int ifindex;
+ struct ndisc_pkt pkt = {0};
+
+ if (parse_opts(argc, argv, &ifindex, &pkt) < 0)
+ return -1;
+
+ fd = socket(AF_PACKET, SOCK_RAW, htons(ETH_P_ALL));
+ if (fd < 0) {
+ fprintf(stderr, "Unable to open raw socket(%d). Need root privileges?\n",
+ fd);
+ return 1;
+ }
+
+ bind_addr.sll_family = AF_PACKET;
+ bind_addr.sll_protocol = htons(ETH_P_ALL);
+ bind_addr.sll_ifindex = ifindex;
+
+ rc = bind(fd, (struct sockaddr *)&bind_addr, sizeof(bind_addr));
+ if (rc < 0) {
+ fprintf(stderr, "Unable to bind raw socket(%d). Invalid iface '%d'?\n",
+ rc, ifindex);
+ return 1;
+ }
+
+ rc = send(fd, &pkt, sizeof(pkt), 0);
+ if (rc < 0) {
+ fprintf(stderr, "Unable to send packet: %d\n", rc);
+ return 1;
+ }
+
+ return 0;
+}
--
2.47.3
^ permalink raw reply related [flat|nested] 8+ messages in thread* Re: [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison)
2026-02-04 22:11 [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison) Marc Suñé
` (3 preceding siblings ...)
2026-02-04 22:12 ` [PATCH net-next v3 4/4] selftests/net: add no NDP b/mcast,null poison test Marc Suñé
@ 2026-02-06 2:31 ` Jakub Kicinski
2026-02-06 14:23 ` Marc Sune
4 siblings, 1 reply; 8+ messages in thread
From: Jakub Kicinski @ 2026-02-06 2:31 UTC (permalink / raw)
To: Marc Suñé
Cc: willemdebruijn.kernel, pabeni, netdev, dborkman, vadim.fedorenko
On Wed, 4 Feb 2026 23:11:57 +0100 Marc Suñé wrote:
> The current ARP and NDP implementations accept announcements with
> multicast (broadcast incl.) and null MAC addresses as Sender HW Address
> (SHA) in ARP or src/target lladdr in NDP, and updates the cache
> for that neighbour.
Doesn't apply for me:
$ git checkout net-next/main
$ git pw series apply 1050919
Failed to apply patch:
Applying: arp: discard invalid sha addr (b/mcast ARP poison)
Applying: selftests/net: add no ARP b/mcast,null poison test
Applying: neigh: discard invalid lladdr (b/mcast poison)
Applying: selftests/net: add no NDP b/mcast,null poison test
error: sha1 information is lacking or useless (tools/testing/selftests/net/Makefile).
error: could not build fake ancestor
hint: Use 'git am --show-current-patch=diff' to see the failed patch
hint: When you have resolved this problem, run "git am --continue".
hint: If you prefer to skip this patch, run "git am --skip" instead.
hint: To restore the original branch and stop patching, run "git am --abort".
hint: Disable this message with "git config set advice.mergeConflict false"
Patch failed at 0004 selftests/net: add no NDP b/mcast,null poison test
--
pw-bot: cr
^ permalink raw reply [flat|nested] 8+ messages in thread* Re: [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison)
2026-02-06 2:31 ` [PATCH net-next v3 0/4] discard ARP/NDP b/mcast/null announce (poison) Jakub Kicinski
@ 2026-02-06 14:23 ` Marc Sune
0 siblings, 0 replies; 8+ messages in thread
From: Marc Sune @ 2026-02-06 14:23 UTC (permalink / raw)
To: Jakub Kicinski
Cc: willemdebruijn.kernel, pabeni, netdev, dborkman, vadim.fedorenko
Missatge de Jakub Kicinski <kuba@kernel.org> del dia dv., 6 de febr.
2026 a les 3:31:
>
> On Wed, 4 Feb 2026 23:11:57 +0100 Marc Suñé wrote:
> > The current ARP and NDP implementations accept announcements with
> > multicast (broadcast incl.) and null MAC addresses as Sender HW Address
> > (SHA) in ARP or src/target lladdr in NDP, and updates the cache
> > for that neighbour.
>
> Doesn't apply for me:
>
> $ git checkout net-next/main
> $ git pw series apply 1050919
Sorry, stupid mistake from my side.
I saw the failure in patchwork, and I was waiting 48h hours to
resubmit v4 without changes, (now) properly rebased.
> Failed to apply patch:
> Applying: arp: discard invalid sha addr (b/mcast ARP poison)
> Applying: selftests/net: add no ARP b/mcast,null poison test
> Applying: neigh: discard invalid lladdr (b/mcast poison)
> Applying: selftests/net: add no NDP b/mcast,null poison test
> error: sha1 information is lacking or useless (tools/testing/selftests/net/Makefile).
> error: could not build fake ancestor
> hint: Use 'git am --show-current-patch=diff' to see the failed patch
> hint: When you have resolved this problem, run "git am --continue".
> hint: If you prefer to skip this patch, run "git am --skip" instead.
> hint: To restore the original branch and stop patching, run "git am --abort".
> hint: Disable this message with "git config set advice.mergeConflict false"
> Patch failed at 0004 selftests/net: add no NDP b/mcast,null poison test
> --
> pw-bot: cr
^ permalink raw reply [flat|nested] 8+ messages in thread