[PATCH 5.4 05/34] vrf: packets with lladdr src needs dst at input with orig_iif when needs strict

From: Greg Kroah-Hartman
Date: Sat Dec 19 2020 - 08:06:24 EST


From: Stephen Suryaputra <ssuryaextr@xxxxxxxxx>

[ Upstream commit 205704c618af0ab2366015d2281a3b0814d918a0 ]

Depending on the order of the routes to fe80::/64 are installed on the
VRF table, the NS for the source link-local address of the originator
might be sent to the wrong interface.

This patch ensures that packets with link-local addr source is doing a
lookup with the orig_iif when the destination addr indicates that it
is strict.

Add the reproducer as a use case in self test script fcnal-test.sh.

Fixes: b4869aa2f881 ("net: vrf: ipv6 support for local traffic to local addresses")
Signed-off-by: Stephen Suryaputra <ssuryaextr@xxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20201204030604.18828-1-ssuryaextr@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/vrf.c | 10 ++-
tools/testing/selftests/net/fcnal-test.sh | 95 ++++++++++++++++++++++++++++++
2 files changed, 103 insertions(+), 2 deletions(-)

--- a/drivers/net/vrf.c
+++ b/drivers/net/vrf.c
@@ -1038,11 +1038,17 @@ static struct sk_buff *vrf_ip6_rcv(struc
int orig_iif = skb->skb_iif;
bool need_strict = rt6_need_strict(&ipv6_hdr(skb)->daddr);
bool is_ndisc = ipv6_ndisc_frame(skb);
+ bool is_ll_src;

/* loopback, multicast & non-ND link-local traffic; do not push through
- * packet taps again. Reset pkt_type for upper layers to process skb
+ * packet taps again. Reset pkt_type for upper layers to process skb.
+ * for packets with lladdr src, however, skip so that the dst can be
+ * determine at input using original ifindex in the case that daddr
+ * needs strict
*/
- if (skb->pkt_type == PACKET_LOOPBACK || (need_strict && !is_ndisc)) {
+ is_ll_src = ipv6_addr_type(&ipv6_hdr(skb)->saddr) & IPV6_ADDR_LINKLOCAL;
+ if (skb->pkt_type == PACKET_LOOPBACK ||
+ (need_strict && !is_ndisc && !is_ll_src)) {
skb->dev = vrf_dev;
skb->skb_iif = vrf_dev->ifindex;
IP6CB(skb)->flags |= IP6SKB_L3SLAVE;
--- a/tools/testing/selftests/net/fcnal-test.sh
+++ b/tools/testing/selftests/net/fcnal-test.sh
@@ -239,6 +239,28 @@ setup_cmd_nsb()
fi
}

+setup_cmd_nsc()
+{
+ local cmd="$*"
+ local rc
+
+ run_cmd_nsc ${cmd}
+ rc=$?
+ if [ $rc -ne 0 ]; then
+ # show user the command if not done so already
+ if [ "$VERBOSE" = "0" ]; then
+ echo "setup command: $cmd"
+ fi
+ echo "failed. stopping tests"
+ if [ "${PAUSE_ON_FAIL}" = "yes" ]; then
+ echo
+ echo "hit enter to continue"
+ read a
+ fi
+ exit $rc
+ fi
+}
+
# set sysctl values in NS-A
set_sysctl()
{
@@ -447,6 +469,36 @@ setup()
sleep 1
}

+setup_lla_only()
+{
+ # make sure we are starting with a clean slate
+ kill_procs
+ cleanup 2>/dev/null
+
+ log_debug "Configuring network namespaces"
+ set -e
+
+ create_ns ${NSA} "-" "-"
+ create_ns ${NSB} "-" "-"
+ create_ns ${NSC} "-" "-"
+ connect_ns ${NSA} ${NSA_DEV} "-" "-" \
+ ${NSB} ${NSB_DEV} "-" "-"
+ connect_ns ${NSA} ${NSA_DEV2} "-" "-" \
+ ${NSC} ${NSC_DEV} "-" "-"
+
+ NSA_LINKIP6=$(get_linklocal ${NSA} ${NSA_DEV})
+ NSB_LINKIP6=$(get_linklocal ${NSB} ${NSB_DEV})
+ NSC_LINKIP6=$(get_linklocal ${NSC} ${NSC_DEV})
+
+ create_vrf ${NSA} ${VRF} ${VRF_TABLE} "-" "-"
+ ip -netns ${NSA} link set dev ${NSA_DEV} vrf ${VRF}
+ ip -netns ${NSA} link set dev ${NSA_DEV2} vrf ${VRF}
+
+ set +e
+
+ sleep 1
+}
+
################################################################################
# IPv4

@@ -3329,10 +3381,53 @@ use_case_br()
setup_cmd_nsb ip li del vlan100 2>/dev/null
}

+# VRF only.
+# ns-A device is connected to both ns-B and ns-C on a single VRF but only has
+# LLA on the interfaces
+use_case_ping_lla_multi()
+{
+ setup_lla_only
+ # only want reply from ns-A
+ setup_cmd_nsb sysctl -qw net.ipv6.icmp.echo_ignore_multicast=1
+ setup_cmd_nsc sysctl -qw net.ipv6.icmp.echo_ignore_multicast=1
+
+ log_start
+ run_cmd_nsb ping -c1 -w1 ${MCAST}%${NSB_DEV}
+ log_test_addr ${MCAST}%${NSB_DEV} $? 0 "Pre cycle, ping out ns-B"
+
+ run_cmd_nsc ping -c1 -w1 ${MCAST}%${NSC_DEV}
+ log_test_addr ${MCAST}%${NSC_DEV} $? 0 "Pre cycle, ping out ns-C"
+
+ # cycle/flap the first ns-A interface
+ setup_cmd ip link set ${NSA_DEV} down
+ setup_cmd ip link set ${NSA_DEV} up
+ sleep 1
+
+ log_start
+ run_cmd_nsb ping -c1 -w1 ${MCAST}%${NSB_DEV}
+ log_test_addr ${MCAST}%${NSB_DEV} $? 0 "Post cycle ${NSA} ${NSA_DEV}, ping out ns-B"
+ run_cmd_nsc ping -c1 -w1 ${MCAST}%${NSC_DEV}
+ log_test_addr ${MCAST}%${NSC_DEV} $? 0 "Post cycle ${NSA} ${NSA_DEV}, ping out ns-C"
+
+ # cycle/flap the second ns-A interface
+ setup_cmd ip link set ${NSA_DEV2} down
+ setup_cmd ip link set ${NSA_DEV2} up
+ sleep 1
+
+ log_start
+ run_cmd_nsb ping -c1 -w1 ${MCAST}%${NSB_DEV}
+ log_test_addr ${MCAST}%${NSB_DEV} $? 0 "Post cycle ${NSA} ${NSA_DEV2}, ping out ns-B"
+ run_cmd_nsc ping -c1 -w1 ${MCAST}%${NSC_DEV}
+ log_test_addr ${MCAST}%${NSC_DEV} $? 0 "Post cycle ${NSA} ${NSA_DEV2}, ping out ns-C"
+}
+
use_cases()
{
log_section "Use cases"
+ log_subsection "Device enslaved to bridge"
use_case_br
+ log_subsection "Ping LLA with multiple interfaces"
+ use_case_ping_lla_multi
}

################################################################################