Re: [PATCH AUTOSEL 5.11 50/67] Drivers: hv: vmbus: Initialize memory to be sent to the host

[Andrea Parri]

On Wed, Feb 24, 2021 at 02:16:00PM +0100, Andrea Parri wrote:
> On Wed, Feb 24, 2021 at 07:50:08AM -0500, Sasha Levin wrote:
> > From: "Andrea Parri (Microsoft)" <parri.andrea@xxxxxxxxx>
> > 
> > [ Upstream commit e99c4afbee07e9323e9191a20b24d74dbf815bdf ]
> > 
> > __vmbus_open() and vmbus_teardown_gpadl() do not inizialite the memory
> > for the vmbus_channel_open_channel and the vmbus_channel_gpadl_teardown
> > objects they allocate respectively.  These objects contain padding bytes
> > and fields that are left uninitialized and that are later sent to the
> > host, potentially leaking guest data.  Zero initialize such fields to
> > avoid leaking sensitive information to the host.
> > 
> > Reported-by: Juan Vazquez <juvazq@xxxxxxxxxxxxx>
> > Signed-off-by: Andrea Parri (Microsoft) <parri.andrea@xxxxxxxxx>
> > Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
> > Link: https://lore.kernel.org/r/20201209070827.29335-2-parri.andrea@xxxxxxxxx
> > Signed-off-by: Wei Liu <wei.liu@xxxxxxxxxx>
> > Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> 
> Sasha - This patch is one of a group of patches where a Linux guest running on
> Hyper-V will start assuming that hypervisor behavior might be malicious, and
> guards against such behavior.  Because this is a new assumption, these patches
> are more properly treated as new functionality rather than as bug fixes.  So I
> would propose that we *not* bring such patches back to stable branches.

For future/similar cases: I'm wondering, is there some way to annotate a patch
with "please do not bring it back"?

Thanks,
  Andrea