4.10-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ding Tianhong <[email protected]> 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 <[email protected]> Acked-by: Al Viro <[email protected]> Signed-off-by: Wei Yongjun <[email protected]> Signed-off-by: Al Viro <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- net/core/datagram.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) --- a/net/core/datagram.c +++ b/net/core/datagram.c @@ -760,7 +760,7 @@ 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 { @@ -768,15 +768,16 @@ 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; }
