| From 5e669e979230cc8abeb5879a33be38a08a969e85 Mon Sep 17 00:00:00 2001 |
| From: Sasha Levin <sashal@kernel.org> |
| Date: Thu, 5 May 2022 14:00:17 +1200 |
| Subject: ipv4: drop dst in multicast routing path |
| |
| From: Lokesh Dhoundiyal <lokesh.dhoundiyal@alliedtelesis.co.nz> |
| |
| [ 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@alliedtelesis.co.nz> |
| Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz> |
| Reviewed-by: David Ahern <dsahern@kernel.org> |
| Link: https://lore.kernel.org/r/20220505020017.3111846-1-chris.packham@alliedtelesis.co.nz |
| Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
| Signed-off-by: Sasha Levin <sashal@kernel.org> |
| --- |
| net/ipv4/route.c | 1 + |
| 1 file changed, 1 insertion(+) |
| |
| diff --git a/net/ipv4/route.c b/net/ipv4/route.c |
| index d5d058de3664..eef07b62b2d8 100644 |
| --- a/net/ipv4/route.c |
| +++ b/net/ipv4/route.c |
| @@ -1748,6 +1748,7 @@ 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; |
| } |
| -- |
| 2.35.1 |
| |