From: Eric Dumazet <[email protected]>
[ Upstream commit 47d3d7fdb10a21c223036b58bd70ffdc24a472c4 ]
Since ip6frag_expire_frag_queue() now pulls the head skb
from frag queue, we should no longer use skb_get(), since
this leads to an skb leak.
Stefan Bader initially reported a problem in 4.4.stable [1] caused
by the skb_get(), so this patch should also fix this issue.
296583.091021] kernel BUG at /build/linux-6VmqmP/linux-4.4.0/net/core/skbuff.c:1207!
[296583.091734] Call Trace:
[296583.091749] [<ffffffff81740e50>] __pskb_pull_tail+0x50/0x350
[296583.091764] [<ffffffff8183939a>] _decode_session6+0x26a/0x400
[296583.091779] [<ffffffff817ec719>] __xfrm_decode_session+0x39/0x50
[296583.091795] [<ffffffff818239d0>] icmpv6_route_lookup+0xf0/0x1c0
[296583.091809] [<ffffffff81824421>] icmp6_send+0x5e1/0x940
[296583.091823] [<ffffffff81753238>] ? __netif_receive_skb+0x18/0x60
[296583.091838] [<ffffffff817532b2>] ? netif_receive_skb_internal+0x32/0xa0
[296583.091858] [<ffffffffc0199f74>] ? ixgbe_clean_rx_irq+0x594/0xac0 [ixgbe]
[296583.091876] [<ffffffffc04eb260>] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6]
[296583.091893] [<ffffffff8183d431>] icmpv6_send+0x21/0x30
[296583.091906] [<ffffffff8182b500>] ip6_expire_frag_queue+0xe0/0x120
[296583.091921] [<ffffffffc04eb27f>] nf_ct_frag6_expire+0x1f/0x30 [nf_defrag_ipv6]
[296583.091938] [<ffffffff810f3b57>] call_timer_fn+0x37/0x140
[296583.091951] [<ffffffffc04eb260>] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6]
[296583.091968] [<ffffffff810f5464>] run_timer_softirq+0x234/0x330
[296583.091982] [<ffffffff8108a339>] __do_softirq+0x109/0x2b0
Fixes: d4289fcc9b16 ("net: IP6 defrag: use rbtrees for IPv6 defrag")
Signed-off-by: Eric Dumazet <[email protected]>
Reported-by: Stefan Bader <[email protected]>
Cc: Peter Oskolkov <[email protected]>
Cc: Florian Westphal <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
---
include/net/ipv6_frag.h | 1 -
1 file changed, 1 deletion(-)
diff --git a/include/net/ipv6_frag.h b/include/net/ipv6_frag.h
index 28aa9b30aecea..1f77fb4dc79df 100644
--- a/include/net/ipv6_frag.h
+++ b/include/net/ipv6_frag.h
@@ -94,7 +94,6 @@ ip6frag_expire_frag_queue(struct net *net, struct frag_queue *fq)
goto out;
head->dev = dev;
- skb_get(head);
spin_unlock(&fq->q.lock);
icmpv6_send(head, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
--
2.20.1
On 22.05.19 21:15, Sasha Levin wrote:
> From: Eric Dumazet <[email protected]>
>
> [ Upstream commit 47d3d7fdb10a21c223036b58bd70ffdc24a472c4 ]
>
> Since ip6frag_expire_frag_queue() now pulls the head skb
> from frag queue, we should no longer use skb_get(), since
> this leads to an skb leak.
>
> Stefan Bader initially reported a problem in 4.4.stable [1] caused
> by the skb_get(), so this patch should also fix this issue.
Just to let everybody know, while changing this has fixed the BUG_ON problem
while sending (in 4.4) it now crashes when releasing just a little later.
Still feels like the right direction but not complete, yet.
-Stefan
>
> 296583.091021] kernel BUG at /build/linux-6VmqmP/linux-4.4.0/net/core/skbuff.c:1207!
> [296583.091734] Call Trace:
> [296583.091749] [<ffffffff81740e50>] __pskb_pull_tail+0x50/0x350
> [296583.091764] [<ffffffff8183939a>] _decode_session6+0x26a/0x400
> [296583.091779] [<ffffffff817ec719>] __xfrm_decode_session+0x39/0x50
> [296583.091795] [<ffffffff818239d0>] icmpv6_route_lookup+0xf0/0x1c0
> [296583.091809] [<ffffffff81824421>] icmp6_send+0x5e1/0x940
> [296583.091823] [<ffffffff81753238>] ? __netif_receive_skb+0x18/0x60
> [296583.091838] [<ffffffff817532b2>] ? netif_receive_skb_internal+0x32/0xa0
> [296583.091858] [<ffffffffc0199f74>] ? ixgbe_clean_rx_irq+0x594/0xac0 [ixgbe]
> [296583.091876] [<ffffffffc04eb260>] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6]
> [296583.091893] [<ffffffff8183d431>] icmpv6_send+0x21/0x30
> [296583.091906] [<ffffffff8182b500>] ip6_expire_frag_queue+0xe0/0x120
> [296583.091921] [<ffffffffc04eb27f>] nf_ct_frag6_expire+0x1f/0x30 [nf_defrag_ipv6]
> [296583.091938] [<ffffffff810f3b57>] call_timer_fn+0x37/0x140
> [296583.091951] [<ffffffffc04eb260>] ? nf_ct_net_exit+0x50/0x50 [nf_defrag_ipv6]
> [296583.091968] [<ffffffff810f5464>] run_timer_softirq+0x234/0x330
> [296583.091982] [<ffffffff8108a339>] __do_softirq+0x109/0x2b0
>
> Fixes: d4289fcc9b16 ("net: IP6 defrag: use rbtrees for IPv6 defrag")
> Signed-off-by: Eric Dumazet <[email protected]>
> Reported-by: Stefan Bader <[email protected]>
> Cc: Peter Oskolkov <[email protected]>
> Cc: Florian Westphal <[email protected]>
> Signed-off-by: David S. Miller <[email protected]>
> Signed-off-by: Sasha Levin <[email protected]>
> ---
> include/net/ipv6_frag.h | 1 -
> 1 file changed, 1 deletion(-)
>
> diff --git a/include/net/ipv6_frag.h b/include/net/ipv6_frag.h
> index 28aa9b30aecea..1f77fb4dc79df 100644
> --- a/include/net/ipv6_frag.h
> +++ b/include/net/ipv6_frag.h
> @@ -94,7 +94,6 @@ ip6frag_expire_frag_queue(struct net *net, struct frag_queue *fq)
> goto out;
>
> head->dev = dev;
> - skb_get(head);
> spin_unlock(&fq->q.lock);
>
> icmpv6_send(head, ICMPV6_TIME_EXCEED, ICMPV6_EXC_FRAGTIME, 0);
>
On Thu, May 23, 2019 at 09:47:23AM +0200, Stefan Bader wrote:
>On 22.05.19 21:15, Sasha Levin wrote:
>> From: Eric Dumazet <[email protected]>
>>
>> [ Upstream commit 47d3d7fdb10a21c223036b58bd70ffdc24a472c4 ]
>>
>> Since ip6frag_expire_frag_queue() now pulls the head skb
>> from frag queue, we should no longer use skb_get(), since
>> this leads to an skb leak.
>>
>> Stefan Bader initially reported a problem in 4.4.stable [1] caused
>> by the skb_get(), so this patch should also fix this issue.
>
>Just to let everybody know, while changing this has fixed the BUG_ON problem
>while sending (in 4.4) it now crashes when releasing just a little later.
>Still feels like the right direction but not complete, yet.
mhm, this commit is really under David's domain, it squeezed through my
filters as it doesn't actually touch net/. I'll drop it for now.
--
Thanks,
Sasha