| Message ID | d1ef9185-0956-aed9-e44b-84458cf28764@huawei.com |
|---|---|
| State | New |
| Headers | show |
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.
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->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; DO you agree this way? :) Thanks Ding > . >
diff --git a/net/core/datagram.c b/net/core/datagram.c index f4947e7..0e6a9a9 100644 --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -768,14 +768,17 @@ int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, if (skb_copy_and_csum_datagram(skb, hlen, &msg->msg_iter, chunk, &csum)) goto fault; - if (csum_fold(csum)) + + if (csum_fold(csum)) { + iov_iter_revert(&msg->msg_iter, chunk); goto csum_error; + } + 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;
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@huawei.com> Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com> --- net/core/datagram.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) -- 1.8.3.1