| Message ID | 20220505020017.3111846-1-chris.packham@alliedtelesis.co.nz (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 9e6c6d17d1d6a3f1515ce399f9a011629ec79aa0 |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net] ipv4: drop dst in multicast routing path | expand |
On 5/4/22 7:00 PM, Chris Packham wrote: > From: Lokesh Dhoundiyal <lokesh.dhoundiyal@alliedtelesis.co.nz> > > 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> > --- > > Notes: > We started seeing this leak in our scenario after commit c0d59da79534 > ("ip_gre: Make none-tun-dst gre tunnel store tunnel info as metadat_dst > in recv") but there may be other paths that hit the leak so I've set the > fixes tag as f38a9eb1f77b ("dst: Metadata destinations"). > > net/ipv4/route.c | 1 + > 1 file changed, 1 insertion(+) > Reviewed-by: David Ahern <dsahern@kernel.org>
Hello: This patch was applied to netdev/net.git (master) by Jakub Kicinski <kuba@kernel.org>: On Thu, 5 May 2022 14:00:17 +1200 you wrote: > From: Lokesh Dhoundiyal <lokesh.dhoundiyal@alliedtelesis.co.nz> > > 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 > > [...] Here is the summary with links: - [net] ipv4: drop dst in multicast routing path https://git.kernel.org/netdev/net/c/9e6c6d17d1d6 You are awesome, thank you!
diff --git a/net/ipv4/route.c b/net/ipv4/route.c index 98c6f3429593..57abd27e842c 100644 --- a/net/ipv4/route.c +++ b/net/ipv4/route.c @@ -1753,6 +1753,7 @@ 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; }