From: "Jason A. Donenfeld" Jason@zx2c4.com
[ Upstream commit ca7a03c4175366a92cee0ccc4fec0038c3266e26 ]
Commit 7d9e5f422150 removed references from certain dsts, but accounting for this never translated down into the fib6 suppression code. This bug was triggered by WireGuard users who use wg-quick(8), which uses the "suppress-prefix" directive to ip-rule(8) for routing all of their internet traffic without routing loops. The test case added here causes the reference underflow by causing packets to evaluate a suppress rule.
Fixes: 7d9e5f422150 ("ipv6: convert major tx path to use RT6_LOOKUP_F_DST_NOREF") Signed-off-by: Jason A. Donenfeld Jason@zx2c4.com Acked-by: Wei Wang weiwan@google.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/ipv6/fib6_rules.c | 3 ++- tools/testing/selftests/net/fib_tests.sh | 17 ++++++++++++++++- 2 files changed, 18 insertions(+), 2 deletions(-)
--- a/net/ipv6/fib6_rules.c +++ b/net/ipv6/fib6_rules.c @@ -287,7 +287,8 @@ static bool fib6_rule_suppress(struct fi return false;
suppress_route: - ip6_rt_put(rt); + if (!(arg->flags & FIB_LOOKUP_NOREF)) + ip6_rt_put(rt); return true; }
--- a/tools/testing/selftests/net/fib_tests.sh +++ b/tools/testing/selftests/net/fib_tests.sh @@ -9,7 +9,7 @@ ret=0 ksft_skip=4
# all tests in this script. Can be overridden with -t option -TESTS="unregister down carrier nexthop ipv6_rt ipv4_rt ipv6_addr_metric ipv4_addr_metric ipv6_route_metrics ipv4_route_metrics ipv4_route_v6_gw rp_filter" +TESTS="unregister down carrier nexthop suppress ipv6_rt ipv4_rt ipv6_addr_metric ipv4_addr_metric ipv6_route_metrics ipv4_route_metrics ipv4_route_v6_gw rp_filter"
VERBOSE=0 PAUSE_ON_FAIL=no @@ -614,6 +614,20 @@ fib_nexthop_test() cleanup }
+fib_suppress_test() +{ + $IP link add dummy1 type dummy + $IP link set dummy1 up + $IP -6 route add default dev dummy1 + $IP -6 rule add table main suppress_prefixlength 0 + ping -f -c 1000 -W 1 1234::1 || true + $IP -6 rule del table main suppress_prefixlength 0 + $IP link del dummy1 + + # If we got here without crashing, we're good. + return 0 +} + ################################################################################ # Tests on route add and replace
@@ -1591,6 +1605,7 @@ do fib_carrier_test|carrier) fib_carrier_test;; fib_rp_filter_test|rp_filter) fib_rp_filter_test;; fib_nexthop_test|nexthop) fib_nexthop_test;; + fib_suppress_test|suppress) fib_suppress_test;; ipv6_route_test|ipv6_rt) ipv6_route_test;; ipv4_route_test|ipv4_rt) ipv4_route_test;; ipv6_addr_metric) ipv6_addr_metric_test;;