On Wed, Feb 21, 2024 at 06:10:03PM -0800, Rick Edgecombe wrote: > On TDX 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. > > Hyperv could free decrypted/shared pages if set_memory_encrypted() fails.
"Hyper-V" throughout. > Leak the pages if this happens. > > Only compile tested. > > Cc: "K. Y. Srinivasan" <[email protected]> > Cc: Haiyang Zhang <[email protected]> > Cc: Wei Liu <[email protected]> > Cc: Dexuan Cui <[email protected]> > Cc: [email protected] > Signed-off-by: Rick Edgecombe <[email protected]> > --- > drivers/hv/connection.c | 11 +++++++---- > 1 file changed, 7 insertions(+), 4 deletions(-) > > diff --git a/drivers/hv/connection.c b/drivers/hv/connection.c > index 3cabeeabb1ca..e39493421bbb 100644 > --- a/drivers/hv/connection.c > +++ b/drivers/hv/connection.c > @@ -315,6 +315,7 @@ int vmbus_connect(void) > > void vmbus_disconnect(void) > { > + int ret; > /* > * First send the unload request to the host. > */ > @@ -337,11 +338,13 @@ void vmbus_disconnect(void) > vmbus_connection.int_page = NULL; > } > > - set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[0], > 1); > - set_memory_encrypted((unsigned long)vmbus_connection.monitor_pages[1], > 1); > + ret = set_memory_encrypted((unsigned > long)vmbus_connection.monitor_pages[0], 1); > + ret |= set_memory_encrypted((unsigned > long)vmbus_connection.monitor_pages[1], 1); > > - hv_free_hyperv_page(vmbus_connection.monitor_pages[0]); > - hv_free_hyperv_page(vmbus_connection.monitor_pages[1]); > + if (!ret) { > + hv_free_hyperv_page(vmbus_connection.monitor_pages[0]); > + hv_free_hyperv_page(vmbus_connection.monitor_pages[1]); > + } This silently leaks the pages if set_memory_encrypted() fails. I think there should print some warning or error messages here. Thanks, Wei. > vmbus_connection.monitor_pages[0] = NULL; > vmbus_connection.monitor_pages[1] = NULL; > } > -- > 2.34.1 >
