4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ding Tianhong <dingtianhong@xxxxxxxxxx>
commit a6a5993243550b09f620941dea741b7421fdf79c upstream.
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.
v2: Sabrina notice that return -EFAULT when checksum error is not correct
here, it would confuse the caller about the return value, so fix it.
Fixes: 327868212381 ("make skb_copy_datagram_msg() et.al. preserve->msg_iter on error")
Signed-off-by: Ding Tianhong <dingtianhong@xxxxxxxxxx>
Acked-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Wei Yongjun <weiyongjun1@xxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/core/datagram.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -740,7 +740,7 @@ int skb_copy_and_csum_datagram_msg(struc
if (msg_data_left(msg) < chunk) {
if (__skb_checksum_complete(skb))
- goto csum_error;
+ return -EINVAL;
if (skb_copy_datagram_msg(skb, hlen, msg, chunk))
goto fault;
} else {
@@ -748,15 +748,16 @@ int skb_copy_and_csum_datagram_msg(struc
if (skb_copy_and_csum_datagram(skb, hlen, &msg->msg_iter,
chunk, &csum))
goto fault;
- if (csum_fold(csum))
- goto csum_error;
+
+ if (csum_fold(csum)) {
+ iov_iter_revert(&msg->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->msg_iter, chunk);
- return -EINVAL;
fault:
return -EFAULT;
}