title: Linux: buffer overrun in netback due to unusual packet
description: The fix for XSA-423 added logic to Linux'es netback driver to deal with
a frontend splitting a packet in a way such that not all of the headers
would come in one piece.  Unfortunately the logic introduced there
didn't account for the extreme case of the entire packet being split
into as many pieces as permitted by the protocol, yet still being
smaller than the area that's specially dealt with to keep all (possible)
headers together.  Such an unusual packet would therefore trigger a
buffer overrun in the driver.
affected:
{
defaultStatus: unknown
product: Linux
vendor: Linux
versions:
status: unknown, version: consult Xen advisory XSA-432
}
workarounds: Using another PV network backend (e.g. the qemu based "qnic" backend)
will mitigate the problem.
Using a dedicated network driver domain per guest will mitigate the
problem.