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| author | David Ahern <dsahern@kernel.org> | 2020-07-06 11:45:07 -0600 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-07-06 13:24:16 -0700 |
| commit | 34fe5a1cf95c3f114068fc16d919c9cf4b00e428 (patch) | |
| tree | e076686ebfd5e67836491ce8ffd31641fb6aeb51 | |
| parent | eadede5f936276e93e62834ffbe1550d305e0921 (diff) | |
| download | linux-34fe5a1cf95c3f114068fc16d919c9cf4b00e428.tar.gz linux-34fe5a1cf95c3f114068fc16d919c9cf4b00e428.tar.bz2 linux-34fe5a1cf95c3f114068fc16d919c9cf4b00e428.zip | |
ipv6: fib6_select_path can not use out path for nexthop objects
Brian reported a crash in IPv6 code when using rpfilter with a setup
running FRR and external nexthop objects. The root cause of the crash
is fib6_select_path setting fib6_nh in the result to NULL because of
an improper check for nexthop objects.
More specifically, rpfilter invokes ip6_route_lookup with flowi6_oif
set causing fib6_select_path to be called with have_oif_match set.
fib6_select_path has early check on have_oif_match and jumps to the
out label which presumes a builtin fib6_nh. This path is invalid for
nexthop objects; for external nexthops fib6_select_path needs to just
return if the fib6_nh has already been set in the result otherwise it
returns after the call to nexthop_path_fib6_result. Update the check
on have_oif_match to not bail on external nexthops.
Update selftests for this problem.
Fixes: f88d8ea67fbd ("ipv6: Plumb support for nexthop object in a fib6_info")
Reported-by: Brian Rak <brak@choopa.com>
Signed-off-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
| -rw-r--r-- | net/ipv6/route.c | 5 | ||||
| -rwxr-xr-x | tools/testing/selftests/net/fib_nexthops.sh | 13 |
2 files changed, 17 insertions, 1 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 82cbb46a2a4f..ea0be7cf3d93 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -431,9 +431,12 @@ void fib6_select_path(const struct net *net, struct fib6_result *res, struct fib6_info *sibling, *next_sibling; struct fib6_info *match = res->f6i; - if ((!match->fib6_nsiblings && !match->nh) || have_oif_match) + if (!match->nh && (!match->fib6_nsiblings || have_oif_match)) goto out; + if (match->nh && have_oif_match && res->nh) + return; + /* We might have already computed the hash for ICMPv6 errors. In such * case it will always be non-zero. Otherwise now is the time to do it. */ diff --git a/tools/testing/selftests/net/fib_nexthops.sh b/tools/testing/selftests/net/fib_nexthops.sh index dee567f7576a..22dc2f3d428b 100755 --- a/tools/testing/selftests/net/fib_nexthops.sh +++ b/tools/testing/selftests/net/fib_nexthops.sh @@ -747,6 +747,19 @@ ipv6_fcnal_runtime() run_cmd "$IP nexthop add id 86 via 2001:db8:91::2 dev veth1" run_cmd "$IP ro add 2001:db8:101::1/128 nhid 81" + # rpfilter and default route + $IP nexthop flush >/dev/null 2>&1 + run_cmd "ip netns exec me ip6tables -t mangle -I PREROUTING 1 -m rpfilter --invert -j DROP" + run_cmd "$IP nexthop add id 91 via 2001:db8:91::2 dev veth1" + run_cmd "$IP nexthop add id 92 via 2001:db8:92::2 dev veth3" + run_cmd "$IP nexthop add id 93 group 91/92" + run_cmd "$IP -6 ro add default nhid 91" + run_cmd "ip netns exec me ping -c1 -w1 2001:db8:101::1" + log_test $? 0 "Nexthop with default route and rpfilter" + run_cmd "$IP -6 ro replace default nhid 93" + run_cmd "ip netns exec me ping -c1 -w1 2001:db8:101::1" + log_test $? 0 "Nexthop with multipath default route and rpfilter" + # TO-DO: # existing route with old nexthop; append route with new nexthop # existing route with old nexthop; replace route with new |