commit c7ec4f2d684e17d69bbdd7c4324db0ef5daac26a upstream.
While frontends may submit zero-size requests (wasting a precious slot),
core networking code as of at least 3ece782693c4b ("sock: skb_copy_ubufs
support for compound pages") can't deal with SKBs when they have all
zero-size fragments. Respond to empty requests right when populating
fragments; all further processing is fragment based and hence won't
encounter these empty requests anymore.
In a way this should have been that way from the beginning: When no data
is to be transferred for a particular request, there's not even a point
in validating the respective grant ref. That's no different from e.g.
passing NULL into memcpy() when at the same time the size is 0.
This is XSA-448 / CVE-2023-46838.
Cc: stable@vger.kernel.org
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Juergen Gross <jgross@suse.com>
Reviewed-by: Paul Durrant <paul@xen.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[ Upstream commit 66cf7435a26917c0c4d6245ad9137e7606e84fdf ]
Do not set netback interfaces (vifs) default TX queue size to the ring size.
The TX queue size is not related to the ring size, and using the ring size (32)
as the queue size can lead to packet drops. Note the TX side of the vif
interface in the netback domain is the one receiving packets to be injected
to the guest.
Do not explicitly set the TX queue length to any value when creating the
interface, and instead use the system default. Note that the queue length can
also be adjusted at runtime.
Fixes: f942dc2552b8 ('xen network backend driver')
Signed-off-by: Roger Pau Monné <roger.pau@citrix.com>
Reviewed-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Acked-by: Wei Liu <wei.liu@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
