Re: [PATCH v2] iov_iter: don't revert iov buffer if csum error

[David Miller]

From: Al Viro 
Date: Sat, 29 Apr 2017 21:48:23 +0100

> On Sat, Apr 29, 2017 at 05:37:38PM +0800, Ding Tianhong wrote:
> 
>> Looks good, if so, we don't need the csum_error any more,
> 
> Acked-by: Al Viro 
> 
> Dave, I could put that through my tree, but I think it would be better off
> in net.git; either way, it needs to go into mainline before -final...

Please just send it directly to Linus, thanks.

Re: [PATCH v2] iov_iter: don't revert iov buffer if csum error

[David Miller]

From: Al Viro 
Date: Sat, 29 Apr 2017 21:48:23 +0100

> On Sat, Apr 29, 2017 at 05:37:38PM +0800, Ding Tianhong wrote:
> 
>> Looks good, if so, we don't need the csum_error any more,
> 
> Acked-by: Al Viro 
> 
> Dave, I could put that through my tree, but I think it would be better off
> in net.git; either way, it needs to go into mainline before -final...

Please just send it directly to Linus, thanks.

Re: [PATCH v2] iov_iter: don't revert iov buffer if csum error

[Al Viro]

On Sat, Apr 29, 2017 at 05:37:38PM +0800, Ding Tianhong wrote:

> Looks good, if so, we don't need the csum_error any more,

Acked-by: Al Viro 

Dave, I could put that through my tree, but I think it would be better off
in net.git; either way, it needs to go into mainline before -final...

Re: [PATCH v2] iov_iter: don't revert iov buffer if csum error

[Al Viro]

On Sat, Apr 29, 2017 at 05:37:38PM +0800, Ding Tianhong wrote:

> Looks good, if so, we don't need the csum_error any more,

Acked-by: Al Viro 

Dave, I could put that through my tree, but I think it would be better off
in net.git; either way, it needs to go into mainline before -final...

Re: [PATCH v2] iov_iter: don't revert iov buffer if csum error

[Ding Tianhong]

On 2017/4/29 10:46, Al Viro wrote:
> On Sat, Apr 29, 2017 at 10:38:48AM +0800, Ding Tianhong wrote:
>> The patch 327868212381 (make skb_copy_datagram_msg() et.al. preserve
>> ->msg_iter on error) will revert the iov buffer if copy to iter
>> failed, but it didn't copy any datagram if the skb_checksum_complete
>> error, so no need to revert any data at this place.
> 
> The bug is real, but I would suggest a simpler fix:
> if (__skb_checksum_complete(skb))
> return -EINVAL;
> leaving the rest as-is.
> 
Looks good, if so, we don't need the csum_error any more,

-   if (csum_fold(csum))
+
+   if (csum_fold(csum)) {
+   iov_iter_revert(>msg_iter, chunk);
+   return -EINVAL;
+   }
+
if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
netdev_rx_csum_fault(skb->dev);
}
return 0;
- csum_error:
-   iov_iter_revert(>msg_iter, chunk);
-   return -EINVAL;
 fault:
return -EFAULT;

DO you agree this way? :)

Thanks
Ding

> .
> 

Re: [PATCH v2] iov_iter: don't revert iov buffer if csum error

[Ding Tianhong]

On 2017/4/29 10:46, Al Viro wrote:
> On Sat, Apr 29, 2017 at 10:38:48AM +0800, Ding Tianhong wrote:
>> The patch 327868212381 (make skb_copy_datagram_msg() et.al. preserve
>> ->msg_iter on error) will revert the iov buffer if copy to iter
>> failed, but it didn't copy any datagram if the skb_checksum_complete
>> error, so no need to revert any data at this place.
> 
> The bug is real, but I would suggest a simpler fix:
> if (__skb_checksum_complete(skb))
> return -EINVAL;
> leaving the rest as-is.
> 
Looks good, if so, we don't need the csum_error any more,

-   if (csum_fold(csum))
+
+   if (csum_fold(csum)) {
+   iov_iter_revert(>msg_iter, chunk);
+   return -EINVAL;
+   }
+
if (unlikely(skb->ip_summed == CHECKSUM_COMPLETE))
netdev_rx_csum_fault(skb->dev);
}
return 0;
- csum_error:
-   iov_iter_revert(>msg_iter, chunk);
-   return -EINVAL;
 fault:
return -EFAULT;

DO you agree this way? :)

Thanks
Ding

> .
> 

Re: [PATCH v2] iov_iter: don't revert iov buffer if csum error

[Al Viro]

On Sat, Apr 29, 2017 at 10:38:48AM +0800, Ding Tianhong wrote:
> The patch 327868212381 (make skb_copy_datagram_msg() et.al. preserve
> ->msg_iter on error) will revert the iov buffer if copy to iter
> failed, but it didn't copy any datagram if the skb_checksum_complete
> error, so no need to revert any data at this place.

The bug is real, but I would suggest a simpler fix:
if (__skb_checksum_complete(skb))
return -EINVAL;
leaving the rest as-is.

Re: [PATCH v2] iov_iter: don't revert iov buffer if csum error

[Al Viro]

On Sat, Apr 29, 2017 at 10:38:48AM +0800, Ding Tianhong wrote:
> The patch 327868212381 (make skb_copy_datagram_msg() et.al. preserve
> ->msg_iter on error) will revert the iov buffer if copy to iter
> failed, but it didn't copy any datagram if the skb_checksum_complete
> error, so no need to revert any data at this place.

The bug is real, but I would suggest a simpler fix:
if (__skb_checksum_complete(skb))
return -EINVAL;
leaving the rest as-is.