* [BUG] ethernet:enic: A use after free bug in enic_hard_start_xmit
@ 2021-04-27 2:55 lyl2019
2021-05-01 0:10 ` Govindarajulu Varadarajan
0 siblings, 1 reply; 3+ messages in thread
From: lyl2019 @ 2021-04-27 2:55 UTC (permalink / raw)
To: benve, _govind, davem, kuba; +Cc: netdev, linux-kernel
Hi, maintainers.
Our code analyzer reported a uaf bug, but it is a little
difficult for me to fix it directly.
File: drivers/net/ethernet/cisco/enic/enic_main.c
In enic_hard_start_xmit, it calls enic_queue_wq_skb(). Inside
enic_queue_wq_skb, if some error happens, the skb will be freed
by dev_kfree_skb(skb). But the freed skb is still used in
skb_tx_timestamp(skb).
```
enic_queue_wq_skb(enic, wq, skb);// skb could freed here
if (vnic_wq_desc_avail(wq) < MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS)
netif_tx_stop_queue(txq);
skb_tx_timestamp(skb); // freed skb is used here.
```
Bug introduced by fb7516d42478e ("enic: add sw timestamp support").
Thanks for your time, looking forwarding to your reply.
Lv Yunlong <lyl2019@mail.ustc.edu.cn>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [BUG] ethernet:enic: A use after free bug in enic_hard_start_xmit
2021-04-27 2:55 [BUG] ethernet:enic: A use after free bug in enic_hard_start_xmit lyl2019
@ 2021-05-01 0:10 ` Govindarajulu Varadarajan
2021-05-01 15:34 ` lyl2019
0 siblings, 1 reply; 3+ messages in thread
From: Govindarajulu Varadarajan @ 2021-05-01 0:10 UTC (permalink / raw)
To: lyl2019, benve, davem, kuba; +Cc: netdev, linux-kernel
On Tue, 2021-04-27 at 10:55 +0800, lyl2019@mail.ustc.edu.cn wrote:
> Hi, maintainers.
> Our code analyzer reported a uaf bug, but it is a little
> difficult for me to fix it directly.
>
> File: drivers/net/ethernet/cisco/enic/enic_main.c
> In enic_hard_start_xmit, it calls enic_queue_wq_skb(). Inside
> enic_queue_wq_skb, if some error happens, the skb will be freed
> by dev_kfree_skb(skb). But the freed skb is still used in
> skb_tx_timestamp(skb).
>
> ```
> enic_queue_wq_skb(enic, wq, skb);// skb could freed here
>
> if (vnic_wq_desc_avail(wq) < MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS)
> netif_tx_stop_queue(txq);
> skb_tx_timestamp(skb); // freed skb is used here.
> ```
> Bug introduced by fb7516d42478e ("enic: add sw timestamp support").
Thank you for reporting this.
One solution is to make enic_queue_wq_skb() return error and goto spin_unlock()
incase of error.
Would you like to send the fix for this?
--
Govind
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Re: [BUG] ethernet:enic: A use after free bug in enic_hard_start_xmit
2021-05-01 0:10 ` Govindarajulu Varadarajan
@ 2021-05-01 15:34 ` lyl2019
0 siblings, 0 replies; 3+ messages in thread
From: lyl2019 @ 2021-05-01 15:34 UTC (permalink / raw)
To: Govindarajulu Varadarajan; +Cc: benve, davem, kuba, netdev, linux-kernel
> -----原始邮件-----
> 发件人: "Govindarajulu Varadarajan" <govind.varadar@gmail.com>
> 发送时间: 2021-05-01 08:10:02 (星期六)
> 收件人: lyl2019@mail.ustc.edu.cn, benve@cisco.com, davem@davemloft.net, kuba@kernel.org
> 抄送: netdev@vger.kernel.org, linux-kernel@vger.kernel.org
> 主题: Re: [BUG] ethernet:enic: A use after free bug in enic_hard_start_xmit
>
> On Tue, 2021-04-27 at 10:55 +0800, lyl2019@mail.ustc.edu.cn wrote:
> > Hi, maintainers.
> > Our code analyzer reported a uaf bug, but it is a little
> > difficult for me to fix it directly.
> >
> > File: drivers/net/ethernet/cisco/enic/enic_main.c
> > In enic_hard_start_xmit, it calls enic_queue_wq_skb(). Inside
> > enic_queue_wq_skb, if some error happens, the skb will be freed
> > by dev_kfree_skb(skb). But the freed skb is still used in
> > skb_tx_timestamp(skb).
> >
> > ```
> > enic_queue_wq_skb(enic, wq, skb);// skb could freed here
> >
> > if (vnic_wq_desc_avail(wq) < MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS)
> > netif_tx_stop_queue(txq);
> > skb_tx_timestamp(skb); // freed skb is used here.
> > ```
> > Bug introduced by fb7516d42478e ("enic: add sw timestamp support").
>
> Thank you for reporting this.
>
> One solution is to make enic_queue_wq_skb() return error and goto spin_unlock()
> incase of error.
>
> Would you like to send the fix for this?
>
> --
> Govind
>
It is my pleasure, i have submitted this fix.
See https://lore.kernel.org/patchwork/patch/1420692/.
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
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2021-04-27 2:55 [BUG] ethernet:enic: A use after free bug in enic_hard_start_xmit lyl2019
2021-05-01 0:10 ` Govindarajulu Varadarajan
2021-05-01 15:34 ` lyl2019
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