From ec831ea72ee5d7d473899e27a86bd659482c4d0d Mon Sep 17 00:00:00 2001 From: Roland Dreier Date: Mon, 31 Jan 2011 13:16:00 -0800 Subject: net: Add default_mtu() methods to blackhole dst_ops When an IPSEC SA is still being set up, __xfrm_lookup() will return -EREMOTE and so ip_route_output_flow() will return a blackhole route. This can happen in a sndmsg call, and after d33e455337ea ("net: Abstract default MTU metric calculation behind an accessor.") this leads to a crash in ip_append_data() because the blackhole dst_ops have no default_mtu() method and so dst_mtu() calls a NULL pointer. Fix this by adding default_mtu() methods (that simply return 0, matching the old behavior) to the blackhole dst_ops. The IPv4 part of this patch fixes a crash that I saw when using an IPSEC VPN; the IPv6 part is untested because I don't have an IPv6 VPN, but it looks to be needed as well. Signed-off-by: Roland Dreier Signed-off-by: David S. Miller --- net/ipv4/route.c | 6 ++++++ net/ipv6/route.c | 6 ++++++ 2 files changed, 12 insertions(+) diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 351dc4e85242..788a3e74834e 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -2707,6 +2707,11 @@ static struct dst_entry *ipv4_blackhole_dst_check(struct dst_entry *dst, u32 coo return NULL; } +static unsigned int ipv4_blackhole_default_mtu(const struct dst_entry *dst) +{ + return 0; +} + static void ipv4_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu) { } @@ -2716,6 +2721,7 @@ static struct dst_ops ipv4_dst_blackhole_ops = { .protocol = cpu_to_be16(ETH_P_IP), .destroy = ipv4_dst_destroy, .check = ipv4_blackhole_dst_check, + .default_mtu = ipv4_blackhole_default_mtu, .update_pmtu = ipv4_rt_blackhole_update_pmtu, }; diff --git a/net/ipv6/route.c b/net/ipv6/route.c index 28a85fc63cb8..1c29f95695de 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c @@ -113,6 +113,11 @@ static struct dst_ops ip6_dst_ops_template = { .local_out = __ip6_local_out, }; +static unsigned int ip6_blackhole_default_mtu(const struct dst_entry *dst) +{ + return 0; +} + static void ip6_rt_blackhole_update_pmtu(struct dst_entry *dst, u32 mtu) { } @@ -122,6 +127,7 @@ static struct dst_ops ip6_dst_blackhole_ops = { .protocol = cpu_to_be16(ETH_P_IPV6), .destroy = ip6_dst_destroy, .check = ip6_dst_check, + .default_mtu = ip6_blackhole_default_mtu, .update_pmtu = ip6_rt_blackhole_update_pmtu, }; -- cgit v1.2.3-59-g8ed1b