From: Xiubo Li <Li.Xiubo@freescale.com>
Date: Sun, 28 Sep 2014 09:09:54 +0000 (+0800)
Subject: regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.
X-Git-Tag: v3.18-rc1~147^2~4^2
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=d6b41cb06044a7d895db82bdd54f6e4219970510;p=karo-tx-linux.git

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@freescale.com>
Signed-off-by: Mark Brown <broonie@kernel.org>
Cc: stable@vger.kernel.org
---

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index b903aff59af3..e677a1b79f95 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1659,6 +1659,9 @@ 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");