drivers/misc/vmw_vmci/vmci_queue_pair.c: fix a couple integer overflow tests

The "DIV_ROUND_UP(size, PAGE_SIZE)" operation can overflow if "size" is
more than ULLONG_MAX - PAGE_SIZE.

Link: http://lkml.kernel.org/r/20170322111950.GA11279@mwanda
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Cc: Jorgen Hansen <jhansen@vmware.com>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/misc/vmw_vmci/vmci_queue_pair.c

@@ -298,8 +298,11 @@ static void *qp_alloc_queue(u64 size, u32 flags)
 	size_t pas_size;
 	size_t vas_size;
 	size_t queue_size = sizeof(*queue) + sizeof(*queue->kernel_if);
-	const u64 num_pages = DIV_ROUND_UP(size, PAGE_SIZE) + 1;
+	u64 num_pages;
 
+	if (size > SIZE_MAX - PAGE_SIZE)
+		return NULL;
+	num_pages = DIV_ROUND_UP(size, PAGE_SIZE) + 1;
 	if (num_pages >
 		 (SIZE_MAX - queue_size) /
 		 (sizeof(*queue->kernel_if->u.g.pas) +
@@ -624,9 +627,12 @@ static struct vmci_queue *qp_host_alloc_queue(u64 size)
 {
 	struct vmci_queue *queue;
 	size_t queue_page_size;
-	const u64 num_pages = DIV_ROUND_UP(size, PAGE_SIZE) + 1;
+	u64 num_pages;
 	const size_t queue_size = sizeof(*queue) + sizeof(*(queue->kernel_if));
 
+	if (size > SIZE_MAX - PAGE_SIZE)
+		return NULL;
+	num_pages = DIV_ROUND_UP(size, PAGE_SIZE) + 1;
 	if (num_pages > (SIZE_MAX - queue_size) /
 		 sizeof(*queue->kernel_if->u.h.page))
 		return NULL;