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).
My patch makes enic_queue_wq_skb() return error and goto spin_unlock()
incase of error. The solution is provided by Govind.
See https://lkml.org/lkml/2021/4/30/961.
Fixes: fb7516d42478e ("enic: add sw timestamp support")
Signed-off-by: Lv Yunlong <[email protected]>
---
drivers/net/ethernet/cisco/enic/enic_main.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c b/drivers/net/ethernet/cisco/enic/enic_main.c
index f04ec53544ae..40abc3fdeba6 100644
--- a/drivers/net/ethernet/cisco/enic/enic_main.c
+++ b/drivers/net/ethernet/cisco/enic/enic_main.c
@@ -768,7 +768,7 @@ static inline int enic_queue_wq_skb_encap(struct enic *enic, struct vnic_wq *wq,
return err;
}
-static inline void enic_queue_wq_skb(struct enic *enic,
+static inline int enic_queue_wq_skb(struct enic *enic,
struct vnic_wq *wq, struct sk_buff *skb)
{
unsigned int mss = skb_shinfo(skb)->gso_size;
@@ -813,7 +813,9 @@ static inline void enic_queue_wq_skb(struct enic *enic,
}
wq->to_use = buf->next;
dev_kfree_skb(skb);
+ return err;
}
+ return err;
}
/* netif_tx_lock held, process context with BHs disabled, or BH */
@@ -857,7 +859,8 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb,
return NETDEV_TX_BUSY;
}
- enic_queue_wq_skb(enic, wq, skb);
+ if (enic_queue_wq_skb(enic, wq, skb) < 0)
+ goto error;
if (vnic_wq_desc_avail(wq) < MAX_SKB_FRAGS + ENIC_DESC_MAX_SPLITS)
netif_tx_stop_queue(txq);
@@ -865,6 +868,7 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff *skb,
if (!netdev_xmit_more() || netif_xmit_stopped(txq))
vnic_wq_doorbell(wq);
+error:
spin_unlock(&enic->wq_lock[txq_map]);
return NETDEV_TX_OK;
--
2.25.1
On Sat, 2021-05-01 at 08:31 -0700, Lv Yunlong wrote:
> 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).
>
> My patch makes enic_queue_wq_skb() return error and goto spin_unlock()
> incase of error. The solution is provided by Govind.
> See https://lkml.org/lkml/2021/4/30/961.
>
> Fixes: fb7516d42478e ("enic: add sw timestamp support")
> Signed-off-by: Lv Yunlong <[email protected]>
> ---
> drivers/net/ethernet/cisco/enic/enic_main.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c
> b/drivers/net/ethernet/cisco/enic/enic_main.c
> index f04ec53544ae..40abc3fdeba6 100644
> --- a/drivers/net/ethernet/cisco/enic/enic_main.c
> +++ b/drivers/net/ethernet/cisco/enic/enic_main.c
> @@ -768,7 +768,7 @@ static inline int enic_queue_wq_skb_encap(struct enic
> *enic, struct vnic_wq *wq,
> return err;
> }
>
> -static inline void enic_queue_wq_skb(struct enic *enic,
> +static inline int enic_queue_wq_skb(struct enic *enic,
> struct vnic_wq *wq, struct sk_buff *skb)
> {
> unsigned int mss = skb_shinfo(skb)->gso_size;
> @@ -813,7 +813,9 @@ static inline void enic_queue_wq_skb(struct enic *enic,
> }
> wq->to_use = buf->next;
> dev_kfree_skb(skb);
> + return err;
return err seems unnecessary here.
> }
> + return err;
> }
>
> /* netif_tx_lock held, process context with BHs disabled, or BH */
> @@ -857,7 +859,8 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff
> *skb,
> return NETDEV_TX_BUSY;
> }
>
> - enic_queue_wq_skb(enic, wq, skb);
> + if (enic_queue_wq_skb(enic, wq, skb) < 0)
0 is success, any other value is error. if (enic_queue_wq_skb(enic, wq, skb)).
Otherwise patch looks good.
Thanks
Govind
> -----原始邮件-----
> 发件人: "Govindarajulu Varadarajan (gvaradar)" <[email protected]>
> 发送时间: 2021-05-02 09:12:49 (星期日)
> 收件人: "Christian Benvenuti (benve)" <[email protected]>, "[email protected]" <[email protected]>, "[email protected]" <[email protected]>, "[email protected]" <[email protected]>
> 抄送: "[email protected]" <[email protected]>, "[email protected]" <[email protected]>, "Govindarajulu
> Varadarajan (gvaradar)" <[email protected]>
> 主题: Re: [PATCH] ethernet:enic: Fix a use after free bug in enic_hard_start_xmit
>
> On Sat, 2021-05-01 at 08:31 -0700, Lv Yunlong wrote:
> > 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).
> >
> > My patch makes enic_queue_wq_skb() return error and goto spin_unlock()
> > incase of error. The solution is provided by Govind.
> > See https://lkml.org/lkml/2021/4/30/961.
> >
> > Fixes: fb7516d42478e ("enic: add sw timestamp support")
> > Signed-off-by: Lv Yunlong <[email protected]>
> > ---
> > drivers/net/ethernet/cisco/enic/enic_main.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/cisco/enic/enic_main.c
> > b/drivers/net/ethernet/cisco/enic/enic_main.c
> > index f04ec53544ae..40abc3fdeba6 100644
> > --- a/drivers/net/ethernet/cisco/enic/enic_main.c
> > +++ b/drivers/net/ethernet/cisco/enic/enic_main.c
> > @@ -768,7 +768,7 @@ static inline int enic_queue_wq_skb_encap(struct enic
> > *enic, struct vnic_wq *wq,
> > return err;
> > }
> >
> > -static inline void enic_queue_wq_skb(struct enic *enic,
> > +static inline int enic_queue_wq_skb(struct enic *enic,
> > struct vnic_wq *wq, struct sk_buff *skb)
> > {
> > unsigned int mss = skb_shinfo(skb)->gso_size;
> > @@ -813,7 +813,9 @@ static inline void enic_queue_wq_skb(struct enic *enic,
> > }
> > wq->to_use = buf->next;
> > dev_kfree_skb(skb);
> > + return err;
>
> return err seems unnecessary here.
>
> > }
> > + return err;
> > }
> >
> > /* netif_tx_lock held, process context with BHs disabled, or BH */
> > @@ -857,7 +859,8 @@ static netdev_tx_t enic_hard_start_xmit(struct sk_buff
> > *skb,
> > return NETDEV_TX_BUSY;
> > }
> >
> > - enic_queue_wq_skb(enic, wq, skb);
> > + if (enic_queue_wq_skb(enic, wq, skb) < 0)
>
> 0 is success, any other value is error. if (enic_queue_wq_skb(enic, wq, skb)).
>
> Otherwise patch looks good.
>
> Thanks
> Govind
Thank you. I have corrected my patch.
See https://lore.kernel.org/patchwork/patch/1420731/.