Re: [PATCH] xen: netfront: Drop GSO SKBs which do not have csum_blank.
flat view
From: Ian Campbell <hidden>
Date: 2011-01-11 11:47:07
Also in:
xen-devel
Hi David, http://patchwork.ozlabs.org/patch/77593/ tells me this patch is "Not Applicable". Is this scenario not worth worrying about for some reason? The error would be due to a buggy peer (i.e. netback) so I guess this frontend fix is really just a belt-and-braces thing. However The equivalent netback patch (which is not upstream yet but I'm working on cleaning it up for a first post soon) is more critical since it could allow a malicious guest to spam the domain 0 syslog (via the WARN_ON in skb_gso_segment) so I just wanted to check if I was also missing some reason why the netback patch would be non-applicable too. Thanks, Ian. On Wed, 2011-01-05 at 13:23 +0000, Ian Campbell wrote:
quoted hunk ↗ jump to hunk
The Linux network stack expects all GSO SKBs to have ip_summed == CHECKSUM_PARTIAL (which implies that the frame contains a partial checksum) and the Xen network ring protocol similarly expects an SKB which has GSO set to also have NETRX_csum_blank (which also implies a partial checksum). Therefore drop such frames on receive otherwise they will trigger the warning in skb_gso_segment. Signed-off-by: Ian Campbell <redacted> Cc: Jeremy Fitzhardinge <redacted> Cc: xen-devel@lists.xensource.com Cc: netdev@vger.kernel.org --- drivers/net/xen-netfront.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-)diff --git a/drivers/net/xen-netfront.c b/drivers/net/xen-netfront.c index cdbeec9..8b8c480 100644 --- a/drivers/net/xen-netfront.c +++ b/drivers/net/xen-netfront.c@@ -836,6 +836,11 @@ static int handle_incoming_queue(struct net_device *dev, dev->stats.rx_errors++; continue; } + } else if (skb_is_gso(skb)) { + kfree_skb(skb); + packets_dropped++; + dev->stats.rx_errors++; + continue; } dev->stats.rx_packets++;