* [PATCH net] mptcp: Fix crash due to tcp_tsorted_anchor was initialized before release skb
@ 2022-03-17 22:09 Mat Martineau
2022-03-18 21:20 ` patchwork-bot+netdevbpf
0 siblings, 1 reply; 2+ messages in thread
From: Mat Martineau @ 2022-03-17 22:09 UTC (permalink / raw)
To: netdev
Cc: Yonglong Li, davem, kuba, matthieu.baerts, mptcp, stable,
Paolo Abeni, Mat Martineau
From: Yonglong Li <liyonglong@chinatelecom.cn>
Got crash when doing pressure test of mptcp:
===========================================================================
dst_release: dst:ffffa06ce6e5c058 refcnt:-1
kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
BUG: unable to handle kernel paging request at ffffa06ce6e5c058
PGD 190a01067 P4D 190a01067 PUD 43fffb067 PMD 22e403063 PTE 8000000226e5c063
Oops: 0011 [#1] SMP PTI
CPU: 7 PID: 7823 Comm: kworker/7:0 Kdump: loaded Tainted: G E
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.2.1 04/01/2014
Call Trace:
? skb_release_head_state+0x68/0x100
? skb_release_all+0xe/0x30
? kfree_skb+0x32/0xa0
? mptcp_sendmsg_frag+0x57e/0x750
? __mptcp_retrans+0x21b/0x3c0
? __switch_to_asm+0x35/0x70
? mptcp_worker+0x25e/0x320
? process_one_work+0x1a7/0x360
? worker_thread+0x30/0x390
? create_worker+0x1a0/0x1a0
? kthread+0x112/0x130
? kthread_flush_work_fn+0x10/0x10
? ret_from_fork+0x35/0x40
===========================================================================
In __mptcp_alloc_tx_skb skb was allocated and skb->tcp_tsorted_anchor will
be initialized, in under memory pressure situation sk_wmem_schedule will
return false and then kfree_skb. In this case skb->_skb_refdst is not null
because_skb_refdst and tcp_tsorted_anchor are stored in the same mem, and
kfree_skb will try to release dst and cause crash.
Fixes: f70cad1085d1 ("mptcp: stop relying on tcp_tx_skb_cache")
Cc: stable@vger.kernel.org
Reviewed-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Yonglong Li <liyonglong@chinatelecom.cn>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
net/mptcp/protocol.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c
index 1c72f25f083e..014c9d88f947 100644
--- a/net/mptcp/protocol.c
+++ b/net/mptcp/protocol.c
@@ -1196,6 +1196,7 @@ static struct sk_buff *__mptcp_alloc_tx_skb(struct sock *sk, struct sock *ssk, g
tcp_skb_entail(ssk, skb);
return skb;
}
+ tcp_skb_tsorted_anchor_cleanup(skb);
kfree_skb(skb);
return NULL;
}
base-commit: 551acdc3c3d2b6bc97f11e31dcf960bc36343bfc
--
2.35.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH net] mptcp: Fix crash due to tcp_tsorted_anchor was initialized before release skb
2022-03-17 22:09 [PATCH net] mptcp: Fix crash due to tcp_tsorted_anchor was initialized before release skb Mat Martineau
@ 2022-03-18 21:20 ` patchwork-bot+netdevbpf
0 siblings, 0 replies; 2+ messages in thread
From: patchwork-bot+netdevbpf @ 2022-03-18 21:20 UTC (permalink / raw)
To: Mat Martineau
Cc: netdev, liyonglong, davem, kuba, matthieu.baerts, mptcp, stable, pabeni
Hello:
This patch was applied to netdev/net.git (master)
by Jakub Kicinski <kuba@kernel.org>:
On Thu, 17 Mar 2022 15:09:53 -0700 you wrote:
> From: Yonglong Li <liyonglong@chinatelecom.cn>
>
> Got crash when doing pressure test of mptcp:
>
> ===========================================================================
> dst_release: dst:ffffa06ce6e5c058 refcnt:-1
> kernel tried to execute NX-protected page - exploit attempt? (uid: 0)
> BUG: unable to handle kernel paging request at ffffa06ce6e5c058
> PGD 190a01067 P4D 190a01067 PUD 43fffb067 PMD 22e403063 PTE 8000000226e5c063
> Oops: 0011 [#1] SMP PTI
> CPU: 7 PID: 7823 Comm: kworker/7:0 Kdump: loaded Tainted: G E
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.2.1 04/01/2014
> Call Trace:
> ? skb_release_head_state+0x68/0x100
> ? skb_release_all+0xe/0x30
> ? kfree_skb+0x32/0xa0
> ? mptcp_sendmsg_frag+0x57e/0x750
> ? __mptcp_retrans+0x21b/0x3c0
> ? __switch_to_asm+0x35/0x70
> ? mptcp_worker+0x25e/0x320
> ? process_one_work+0x1a7/0x360
> ? worker_thread+0x30/0x390
> ? create_worker+0x1a0/0x1a0
> ? kthread+0x112/0x130
> ? kthread_flush_work_fn+0x10/0x10
> ? ret_from_fork+0x35/0x40
> ===========================================================================
>
> [...]
Here is the summary with links:
- [net] mptcp: Fix crash due to tcp_tsorted_anchor was initialized before release skb
https://git.kernel.org/netdev/net/c/3ef3905aa3b5
You are awesome, thank you!
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