linux-kernel - [PATCH][next] intel_th: msu: fix overflow in shift of an unsigned int

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Date:   Fri, 26 Jul 2019 12:31:51 +0100
From:   Colin King <colin.king@...onical.com>
To:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc:     kernel-janitors@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH][next] intel_th: msu: fix overflow in shift of an unsigned int

From: Colin Ian King <colin.king@...onical.com>

The shift of the unsigned int win->nr_blocks by PAGE_SHIFT may
potentially overflow. Note that the intended return of this shift
is expected to be a size_t however the shift is being performed as
an unsigned int.  Fix this by casting win->nr_blocks to a size_t
before performing the shift.

Addresses-Coverity: ("Unintentional integer overflow")
Fixes: 615c164da0eb ("intel_th: msu: Introduce buffer interface")
Signed-off-by: Colin Ian King <colin.king@...onical.com>
---
 drivers/hwtracing/intel_th/msu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwtracing/intel_th/msu.c b/drivers/hwtracing/intel_th/msu.c
index fc9f15f36ad4..4892ac446c01 100644
--- a/drivers/hwtracing/intel_th/msu.c
+++ b/drivers/hwtracing/intel_th/msu.c
@@ -327,7 +327,7 @@ static size_t msc_win_total_sz(struct msc_window *win)
 		struct msc_block_desc *bdesc = sg_virt(sg);
 
 		if (msc_block_wrapped(bdesc))
-			return win->nr_blocks << PAGE_SHIFT;
+			return (size_t)win->nr_blocks << PAGE_SHIFT;
 
 		size += msc_total_sz(bdesc);
 		if (msc_block_last_written(bdesc))
-- 
2.20.1