| Message ID | 20190904094211.117454-1-maowenan@huawei.com |
|---|---|
| State | Changes Requested |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] net: sonic: remove dev_kfree_skb before return NETDEV_TX_BUSY | expand |
On Wed, Sep 04, 2019 at 05:42:11PM +0800, Mao Wenan wrote: > When dma_map_single is failed to map buffer, skb can't be freed > before sonic driver return to stack with NETDEV_TX_BUSY, because > this skb may be requeued to qdisc, it might trigger use-after-free. > > Fixes: d9fb9f384292 ("*sonic/natsemi/ns83829: Move the National Semi-conductor drivers") > Signed-off-by: Mao Wenan <maowenan@huawei.com> > --- > drivers/net/ethernet/natsemi/sonic.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/net/ethernet/natsemi/sonic.c b/drivers/net/ethernet/natsemi/sonic.c > index d0a01e8f000a..248a8f22a33b 100644 > --- a/drivers/net/ethernet/natsemi/sonic.c > +++ b/drivers/net/ethernet/natsemi/sonic.c > @@ -233,7 +233,6 @@ static int sonic_send_packet(struct sk_buff *skb, struct net_device *dev) > laddr = dma_map_single(lp->device, skb->data, length, DMA_TO_DEVICE); > if (!laddr) { > printk(KERN_ERR "%s: failed to map tx DMA buffer.\n", dev->name); > - dev_kfree_skb(skb); > return NETDEV_TX_BUSY; > } Reviewed-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Thomas.
On 9/4/19 11:42 AM, Mao Wenan wrote: > When dma_map_single is failed to map buffer, skb can't be freed > before sonic driver return to stack with NETDEV_TX_BUSY, because > this skb may be requeued to qdisc, it might trigger use-after-free. > > Fixes: d9fb9f384292 ("*sonic/natsemi/ns83829: Move the National Semi-conductor drivers") > Signed-off-by: Mao Wenan <maowenan@huawei.com> > --- > drivers/net/ethernet/natsemi/sonic.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/drivers/net/ethernet/natsemi/sonic.c b/drivers/net/ethernet/natsemi/sonic.c > index d0a01e8f000a..248a8f22a33b 100644 > --- a/drivers/net/ethernet/natsemi/sonic.c > +++ b/drivers/net/ethernet/natsemi/sonic.c > @@ -233,7 +233,6 @@ static int sonic_send_packet(struct sk_buff *skb, struct net_device *dev) > laddr = dma_map_single(lp->device, skb->data, length, DMA_TO_DEVICE); > if (!laddr) { > printk(KERN_ERR "%s: failed to map tx DMA buffer.\n", dev->name); > - dev_kfree_skb(skb); > return NETDEV_TX_BUSY; > } > > That is the wrong way to fix this bug. What guarantee do we have that the mapping operation will succeed next time we attempt the transmit (and the dma_map_single() operation) ? NETDEV_TX_BUSY is very dangerous, this might trigger an infinite loop. I would rather leave the dev_kfree_skb(skb), and return NETDEV_TX_OK Also the printk(KERN_ERR ...) should be replaced by pr_err_ratelimited(...) NETDEV_TX_BUSY really should only be used by drivers that call netif_tx_stop_queue() at the wrong moment.
On 2019/9/4 18:19, Eric Dumazet wrote: > > > On 9/4/19 11:42 AM, Mao Wenan wrote: >> When dma_map_single is failed to map buffer, skb can't be freed >> before sonic driver return to stack with NETDEV_TX_BUSY, because >> this skb may be requeued to qdisc, it might trigger use-after-free. >> >> Fixes: d9fb9f384292 ("*sonic/natsemi/ns83829: Move the National Semi-conductor drivers") >> Signed-off-by: Mao Wenan <maowenan@huawei.com> >> --- >> drivers/net/ethernet/natsemi/sonic.c | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/drivers/net/ethernet/natsemi/sonic.c b/drivers/net/ethernet/natsemi/sonic.c >> index d0a01e8f000a..248a8f22a33b 100644 >> --- a/drivers/net/ethernet/natsemi/sonic.c >> +++ b/drivers/net/ethernet/natsemi/sonic.c >> @@ -233,7 +233,6 @@ static int sonic_send_packet(struct sk_buff *skb, struct net_device *dev) >> laddr = dma_map_single(lp->device, skb->data, length, DMA_TO_DEVICE); >> if (!laddr) { >> printk(KERN_ERR "%s: failed to map tx DMA buffer.\n", dev->name); >> - dev_kfree_skb(skb); >> return NETDEV_TX_BUSY; >> } >> >> > > That is the wrong way to fix this bug. > > What guarantee do we have that the mapping operation will succeed next time we attempt > the transmit (and the dma_map_single() operation) ? > > NETDEV_TX_BUSY is very dangerous, this might trigger an infinite loop. > > I would rather leave the dev_kfree_skb(skb), and return NETDEV_TX_OK yes, right, it will go to infinite loop if dma_map_single failed always. v2 will be sent later. > > Also the printk(KERN_ERR ...) should be replaced by pr_err_ratelimited(...) > > NETDEV_TX_BUSY really should only be used by drivers that call netif_tx_stop_queue() > at the wrong moment. It will call netif_tx_stop_queue() then return NETDEV_TX_BUSY, and give a chance to netif_tx_wake_queue(), then stack can be resent packet to driver? > > . >
diff --git a/drivers/net/ethernet/natsemi/sonic.c b/drivers/net/ethernet/natsemi/sonic.c index d0a01e8f000a..248a8f22a33b 100644 --- a/drivers/net/ethernet/natsemi/sonic.c +++ b/drivers/net/ethernet/natsemi/sonic.c @@ -233,7 +233,6 @@ static int sonic_send_packet(struct sk_buff *skb, struct net_device *dev) laddr = dma_map_single(lp->device, skb->data, length, DMA_TO_DEVICE); if (!laddr) { printk(KERN_ERR "%s: failed to map tx DMA buffer.\n", dev->name); - dev_kfree_skb(skb); return NETDEV_TX_BUSY; }
When dma_map_single is failed to map buffer, skb can't be freed before sonic driver return to stack with NETDEV_TX_BUSY, because this skb may be requeued to qdisc, it might trigger use-after-free. Fixes: d9fb9f384292 ("*sonic/natsemi/ns83829: Move the National Semi-conductor drivers") Signed-off-by: Mao Wenan <maowenan@huawei.com> --- drivers/net/ethernet/natsemi/sonic.c | 1 - 1 file changed, 1 deletion(-)