Re: [PATCH][v4] virt: tdx-guest: Don't free decrypted memory

[Edgecombe, Rick P]

On Mon, 2024-12-02 at 10:05 -0800, Dave Hansen wrote:
> On 11/27/24 08:48, Edgecombe, Rick P wrote:
> > On Wed, 2024-06-19 at 19:18 +0800, Li RongQing wrote:
> > > In CoCo VMs it is possible for the untrusted host to cause
> > > set_memory_decrypted() to fail such that an error is returned
> > > and the resulting memory is shared. Callers need to take care
> > > to handle these errors to avoid returning decrypted (shared)
> > > memory to the page allocator, which could lead to functional
> > > or security issues.
> > > 
> > > Leak the decrypted memory when set_memory_decrypted() fails,
> > > and don't need to print an error since set_memory_decrypted()
> > > will call WARN_ONCE().
> > > 
> > > Reviewed-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
> > > Reviewed-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> > > Signed-off-by: Li RongQing <lirongqing@xxxxxxxxx>
> > It needs a Fixes tag.
> > Fixes: f4738f56d1dc ("virt: tdx-guest: Add Quote generation support using
> > TSM_REPORTS")
> > 
> > I think it is a worthwhile fix. Without it the guest can be tricked into freeing
> > shared pages, or trying to execute from them and crashing.
> 
> Does this need a "Fixes" and cc:stable@?

Oh yea, probably worth a cc:stable too.