This is a note to let you know that I've just added the patch titled
ipv4: drop dst in multicast routing path
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
ipv4-drop-dst-in-multicast-routing-path.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit cb6cb4190a053e60712d339a594e6c1261f597d9
Author: Lokesh Dhoundiyal <lokesh.dhoundiyal@xxxxxxxxxxxxxxxxxxx>
Date: Thu May 5 14:00:17 2022 +1200
ipv4: drop dst in multicast routing path
[ Upstream commit 9e6c6d17d1d6a3f1515ce399f9a011629ec79aa0 ]
kmemleak reports the following when routing multicast traffic over an
ipsec tunnel.
Kmemleak output:
unreferenced object 0x8000000044bebb00 (size 256):
comm "softirq", pid 0, jiffies 4294985356 (age 126.810s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 80 00 00 00 05 13 74 80 ..............t.
80 00 00 00 04 9b bf f9 00 00 00 00 00 00 00 00 ................
backtrace:
[<00000000f83947e0>] __kmalloc+0x1e8/0x300
[<00000000b7ed8dca>] metadata_dst_alloc+0x24/0x58
[<0000000081d32c20>] __ipgre_rcv+0x100/0x2b8
[<00000000824f6cf1>] gre_rcv+0x178/0x540
[<00000000ccd4e162>] gre_rcv+0x7c/0xd8
[<00000000c024b148>] ip_protocol_deliver_rcu+0x124/0x350
[<000000006a483377>] ip_local_deliver_finish+0x54/0x68
[<00000000d9271b3a>] ip_local_deliver+0x128/0x168
[<00000000bd4968ae>] xfrm_trans_reinject+0xb8/0xf8
[<0000000071672a19>] tasklet_action_common.isra.16+0xc4/0x1b0
[<0000000062e9c336>] __do_softirq+0x1fc/0x3e0
[<00000000013d7914>] irq_exit+0xc4/0xe0
[<00000000a4d73e90>] plat_irq_dispatch+0x7c/0x108
[<000000000751eb8e>] handle_int+0x16c/0x178
[<000000001668023b>] _raw_spin_unlock_irqrestore+0x1c/0x28
The metadata dst is leaked when ip_route_input_mc() updates the dst for
the skb. Commit f38a9eb1f77b ("dst: Metadata destinations") correctly
handled dropping the dst in ip_route_input_slow() but missed the
multicast case which is handled by ip_route_input_mc(). Drop the dst in
ip_route_input_mc() avoiding the leak.
Fixes: f38a9eb1f77b ("dst: Metadata destinations")
Signed-off-by: Lokesh Dhoundiyal <lokesh.dhoundiyal@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
Reviewed-by: David Ahern <dsahern@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20220505020017.3111846-1-chris.packham@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index f05b8d63dba3..624bdd74583b 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -1606,6 +1606,7 @@ static int ip_route_input_mc(struct sk_buff *skb, __be32 daddr, __be32 saddr,
#endif
RT_CACHE_STAT_INC(in_slow_mc);
+ skb_dst_drop(skb);
skb_dst_set(skb, &rth->dst);
return 0;
