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. 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]); + } vmbus_connection.monitor_pages[0] = NULL; vmbus_connection.monitor_pages[1] = NULL; } -- 2.34.1
