Add test cases that exercise the scenario where an IPv6 nexthop is replaced with an IPv4 nexthop while being part of a group. The group's has_v4 flag must be updated so that subsequent IPv6 route additions are properly rejected. Two cases are covered: 1. Gateway nexthop replaced across families with an existing IPv6 route on the group (rejected by fib6_check_nh_list). 2. Blackhole nexthop replaced across families with no existing IPv6 route on the group (fib6_check_nh_list returns early) — this is the path that triggers a NULL ptr deref without the kernel fix. Signed-off-by: Jiayuan Chen --- tools/testing/selftests/net/fib_nexthops.sh | 22 +++++++++++++++++++++ 1 file changed, 22 insertions(+) diff --git a/tools/testing/selftests/net/fib_nexthops.sh b/tools/testing/selftests/net/fib_nexthops.sh index 6eb7f95e70e1..ac868a731694 100755 --- a/tools/testing/selftests/net/fib_nexthops.sh +++ b/tools/testing/selftests/net/fib_nexthops.sh @@ -1209,6 +1209,28 @@ ipv6_fcnal_runtime() run_cmd "$IP ro replace 2001:db8:101::1/128 nhid 124" log_test $? 0 "IPv6 route using a group after replacing v4 gateways" + # Replacing an IPv6 nexthop with an IPv4 nexthop should update has_v4 + # for all groups using it, preventing IPv6 routes from referencing the + # group after the replace. + run_cmd "$IP nexthop add id 89 via 2001:db8:91::2 dev veth1" + run_cmd "$IP nexthop add id 125 group 89" + run_cmd "$IP nexthop replace id 89 via 172.16.1.1 dev veth1" + run_cmd "$IP ro replace 2001:db8:101::1/128 nhid 125" + log_test $? 2 "IPv6 route can not use group after v6 nexthop replaced by v4" + + # Same scenario but with a blackhole nexthop: the group has no IPv6 + # routes yet when the replace happens, so fib6_check_nh_list returns + # early without checking. has_v4 must still be updated to block + # subsequent IPv6 route additions. + run_cmd "$IP nexthop flush >/dev/null 2>&1" + run_cmd "$IP -6 nexthop add id 90 blackhole" + run_cmd "$IP nexthop add id 125 group 90" + run_cmd "$IP nexthop replace id 90 blackhole" + run_cmd "$IP -6 ro add 2001:db8:101::1/128 nhid 125" + log_test $? 2 "IPv6 route reject v6 blackhole replaced by v4 blackhole" + run_cmd "ip netns exec $me ping -6 2001:db8:101::1 -c1 -w$PING_TIMEOUT" + log_test $? 2 "Ping unreachable after rejected route" + $IP nexthop flush >/dev/null 2>&1 # -- 2.43.0