Commit 8c2d5e06 authored by Andrea Parri (Microsoft)'s avatar Andrea Parri (Microsoft) Committed by Wei Liu
Browse files

Drivers: hv: vmbus: Initialize unload_event statically 



If a malicious or compromised Hyper-V sends a spurious message of type
CHANNELMSG_UNLOAD_RESPONSE, the function vmbus_unload_response() will
call complete() on an uninitialized event, and cause an oops.

Reported-by: default avatarMichael Kelley <mikelley@microsoft.com>
Signed-off-by: default avatarAndrea Parri (Microsoft) <parri.andrea@gmail.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210420014350.2002-1-parri.andrea@gmail.com


Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
parent b635ccc1

drivers/hv/channel_mgmt.c

+6 −1
Original line number Diff line number Diff line
@@ -826,6 +826,11 @@ static void vmbus_unload_response(struct vmbus_channel_message_header *hdr) 
	/*

	 * This is a global event; just wakeup the waiting thread.

	 * Once we successfully unload, we can cleanup the monitor state.

	 *

	 * NB.  A malicious or compromised Hyper-V could send a spurious

	 * message of type CHANNELMSG_UNLOAD_RESPONSE, and trigger a call

	 * of the complete() below.  Make sure that unload_event has been

	 * initialized by the time this complete() is executed.

	 */

	complete(&vmbus_connection.unload_event);

}
@@ -841,7 +846,7 @@ void vmbus_initiate_unload(bool crash) 
	if (vmbus_proto_version < VERSION_WIN8_1)

		return;



	init_completion(&vmbus_connection.unload_event);

	reinit_completion(&vmbus_connection.unload_event);

	memset(&hdr, 0, sizeof(struct vmbus_channel_message_header));

	hdr.msgtype = CHANNELMSG_UNLOAD;

	vmbus_post_msg(&hdr, sizeof(struct vmbus_channel_message_header),

drivers/hv/connection.c

+2 −0
Original line number Diff line number Diff line
@@ -26,6 +26,8 @@ 


struct vmbus_connection vmbus_connection = {

	.conn_state		= DISCONNECTED,

	.unload_event		= COMPLETION_INITIALIZER(

				  vmbus_connection.unload_event),

	.next_gpadl_handle	= ATOMIC_INIT(0xE1E10),



	.ready_for_suspend_event = COMPLETION_INITIALIZER(