| Message ID | 20240311161558.1310-6-mhklinux@outlook.com (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
| Series | Handle set_memory_XXcrypted() errors in Hyper-V | expand |
On 3/11/24 9:15 AM, mhkelley58@gmail.com wrote: > From: Michael Kelley <mhklinux@outlook.com> > > In CoCo VMs it is possible for the untrusted host to cause > set_memory_encrypted() or 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. > > The VMBus ring buffer code could free decrypted/shared pages if > set_memory_decrypted() fails. Check the decrypted field in the struct > vmbus_gpadl for the ring buffers to decide whether to free the memory. > > Signed-off-by: Michael Kelley <mhklinux@outlook.com> > --- Looks good to me. Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com> > drivers/hv/channel.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c > index bb5abdcda18f..47e1bd8de9fc 100644 > --- a/drivers/hv/channel.c > +++ b/drivers/hv/channel.c > @@ -153,7 +153,9 @@ void vmbus_free_ring(struct vmbus_channel *channel) > hv_ringbuffer_cleanup(&channel->inbound); > > if (channel->ringbuffer_page) { > - __free_pages(channel->ringbuffer_page, > + /* In a CoCo VM leak the memory if it didn't get re-encrypted */ > + if (!channel->ringbuffer_gpadlhandle.decrypted) > + __free_pages(channel->ringbuffer_page, > get_order(channel->ringbuffer_pagecount > << PAGE_SHIFT)); > channel->ringbuffer_page = NULL;
diff --git a/drivers/hv/channel.c b/drivers/hv/channel.c index bb5abdcda18f..47e1bd8de9fc 100644 --- a/drivers/hv/channel.c +++ b/drivers/hv/channel.c @@ -153,7 +153,9 @@ void vmbus_free_ring(struct vmbus_channel *channel) hv_ringbuffer_cleanup(&channel->inbound); if (channel->ringbuffer_page) { - __free_pages(channel->ringbuffer_page, + /* In a CoCo VM leak the memory if it didn't get re-encrypted */ + if (!channel->ringbuffer_gpadlhandle.decrypted) + __free_pages(channel->ringbuffer_page, get_order(channel->ringbuffer_pagecount << PAGE_SHIFT)); channel->ringbuffer_page = NULL;