[PATCH AUTOSEL for 4.9 021/281] drivers/misc/vmw_vmci/vmci_queue_pair.c: fix a couple integer overflow tests

[Sasha Levin]

From: Dan Carpenter <dan.carpenter@xxxxxxxxxx>

[ Upstream commit 146180c052a00172f4dc08eaade836fd02f61fb5 ]

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@xxxxxxxxxx>
Cc: Jorgen Hansen <jhansen@xxxxxxxxxx>
Cc: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
---
 drivers/misc/vmw_vmci/vmci_queue_pair.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index f84a4275ca29..f735ab4ba84e 100644
--- a/drivers/misc/vmw_vmci/vmci_queue_pair.c
+++ b/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;
-- 
2.14.1