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* [PATCH] vmci: Fix a couple integer overflow tests
@ 2017-03-22 11:19 Dan Carpenter
  0 siblings, 0 replies; 1+ messages in thread
From: Dan Carpenter @ 2017-03-22 11:19 UTC (permalink / raw)
  To: Michal Hocko, Jorgen Hansen
  Cc: Masahiro Yamada, Andy King, Michal Hocko, Andrew Morton,
	linux-kernel, kernel-janitors

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

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

diff --git a/drivers/misc/vmw_vmci/vmci_queue_pair.c b/drivers/misc/vmw_vmci/vmci_queue_pair.c
index 498c0854305f..06c4974ee8dd 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;

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2017-03-22 11:19 [PATCH] vmci: Fix a couple integer overflow tests Dan Carpenter

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