linux-kernel - [PATCH] regmap: fix possible ZERO_SIZE

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Date:	Sun, 28 Sep 2014 17:09:54 +0800
From:	Xiubo Li <Li.Xiubo@...escale.com>
To:	<broonie@...nel.org>
CC:	<gregkh@...uxfoundation.org>, <linux-kernel@...r.kernel.org>,
	Xiubo Li <Li.Xiubo@...escale.com>
Subject: [PATCH] regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.

Since we cannot make sure the 'val_count' will always be none zero
here, and then if it equals to zero, the kmemdup() will return
ZERO_SIZE_PTR, which equals to ((void *)16).

So this patch fix this with just doing the zero check before calling
kmemdup().

Signed-off-by: Xiubo Li <Li.Xiubo@...escale.com>
---
 drivers/base/regmap/regmap.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 455a877..3d93e38 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1716,6 +1716,9 @@ out:
 	} else {
 		void *wval;
 
+		if (!val_count)
+			return -EINVAL;
+
 		wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL);
 		if (!wval) {
 			dev_err(map->dev, "Error in memory allocation\n");
-- 
2.1.0.27.g96db324

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