1 files changed, 47 insertions, 17 deletions

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index d491fdcee61f..10dce9f91216 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -678,6 +678,23 @@ static const struct attribute_group vmbus_dev_group = {
 };
 __ATTRIBUTE_GROUPS(vmbus_dev);
 
+/* Set up the attribute for /sys/bus/vmbus/hibernation */
+static ssize_t hibernation_show(struct bus_type *bus, char *buf)
+{
+	return sprintf(buf, "%d\n", !!hv_is_hibernation_supported());
+}
+
+static BUS_ATTR_RO(hibernation);
+
+static struct attribute *vmbus_bus_attrs[] = {
+	&bus_attr_hibernation.attr,
+	NULL,
+};
+static const struct attribute_group vmbus_bus_group = {
+	.attrs = vmbus_bus_attrs,
+};
+__ATTRIBUTE_GROUPS(vmbus_bus);
+
 /*
  * vmbus_uevent - add uevent for our device
  *
@@ -1024,6 +1041,7 @@ static struct bus_type  hv_bus = {
 	.uevent =		vmbus_uevent,
 	.dev_groups =		vmbus_dev_groups,
 	.drv_groups =		vmbus_drv_groups,
+	.bus_groups =		vmbus_bus_groups,
 	.pm =			&vmbus_pm,
 };
 
@@ -1054,12 +1072,14 @@ void vmbus_on_msg_dpc(unsigned long data)
 {
 	struct hv_per_cpu_context *hv_cpu = (void *)data;
 	void *page_addr = hv_cpu->synic_message_page;
-	struct hv_message *msg = (struct hv_message *)page_addr +
+	struct hv_message msg_copy, *msg = (struct hv_message *)page_addr +
 				  VMBUS_MESSAGE_SINT;
 	struct vmbus_channel_message_header *hdr;
+	enum vmbus_channel_message_type msgtype;
 	const struct vmbus_channel_message_table_entry *entry;
 	struct onmessage_work_context *ctx;
-	u32 message_type = msg->header.message_type;
+	__u8 payload_size;
+	u32 message_type;
 
 	/*
 	 * 'enum vmbus_channel_message_type' is supposed to always be 'u32' as
@@ -1068,45 +1088,52 @@ void vmbus_on_msg_dpc(unsigned long data)
 	 */
 	BUILD_BUG_ON(sizeof(enum vmbus_channel_message_type) != sizeof(u32));
 
+	/*
+	 * Since the message is in memory shared with the host, an erroneous or
+	 * malicious Hyper-V could modify the message while vmbus_on_msg_dpc()
+	 * or individual message handlers are executing; to prevent this, copy
+	 * the message into private memory.
+	 */
+	memcpy(&msg_copy, msg, sizeof(struct hv_message));
+
+	message_type = msg_copy.header.message_type;
 	if (message_type == HVMSG_NONE)
 		/* no msg */
 		return;
 
-	hdr = (struct vmbus_channel_message_header *)msg->u.payload;
+	hdr = (struct vmbus_channel_message_header *)msg_copy.u.payload;
+	msgtype = hdr->msgtype;
 
 	trace_vmbus_on_msg_dpc(hdr);
 
-	if (hdr->msgtype >= CHANNELMSG_COUNT) {
-		WARN_ONCE(1, "unknown msgtype=%d\n", hdr->msgtype);
+	if (msgtype >= CHANNELMSG_COUNT) {
+		WARN_ONCE(1, "unknown msgtype=%d\n", msgtype);
 		goto msg_handled;
 	}
 
-	if (msg->header.payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) {
-		WARN_ONCE(1, "payload size is too large (%d)\n",
-			  msg->header.payload_size);
+	payload_size = msg_copy.header.payload_size;
+	if (payload_size > HV_MESSAGE_PAYLOAD_BYTE_COUNT) {
+		WARN_ONCE(1, "payload size is too large (%d)\n", payload_size);
 		goto msg_handled;
 	}
 
-	entry = &channel_message_table[hdr->msgtype];
+	entry = &channel_message_table[msgtype];
 
 	if (!entry->message_handler)
 		goto msg_handled;
 
-	if (msg->header.payload_size < entry->min_payload_len) {
-		WARN_ONCE(1, "message too short: msgtype=%d len=%d\n",
-			  hdr->msgtype, msg->header.payload_size);
+	if (payload_size < entry->min_payload_len) {
+		WARN_ONCE(1, "message too short: msgtype=%d len=%d\n", msgtype, payload_size);
 		goto msg_handled;
 	}
 
 	if (entry->handler_type	== VMHT_BLOCKING) {
-		ctx = kmalloc(sizeof(*ctx) + msg->header.payload_size,
-			      GFP_ATOMIC);
+		ctx = kmalloc(sizeof(*ctx) + payload_size, GFP_ATOMIC);
 		if (ctx == NULL)
 			return;
 
 		INIT_WORK(&ctx->work, vmbus_onmessage_work);
-		memcpy(&ctx->msg, msg, sizeof(msg->header) +
-		       msg->header.payload_size);
+		memcpy(&ctx->msg, &msg_copy, sizeof(msg->header) + payload_size);
 
 		/*
 		 * The host can generate a rescind message while we
@@ -1115,7 +1142,7 @@ void vmbus_on_msg_dpc(unsigned long data)
 		 * by offer_in_progress and by channel_mutex.  See also the
 		 * inline comments in vmbus_onoffer_rescind().
 		 */
-		switch (hdr->msgtype) {
+		switch (msgtype) {
 		case CHANNELMSG_RESCIND_CHANNELOFFER:
 			/*
 			 * If we are handling the rescind message;
@@ -2618,6 +2645,9 @@ static int __init hv_acpi_init(void)
 	if (!hv_is_hyperv_initialized())
 		return -ENODEV;
 
+	if (hv_root_partition)
+		return 0;
+
 	init_completion(&probe_event);
 
 	/*