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: v3.12.32~49
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=a0b8d8d906d267987d507138003048c5fdf77473;p=thirdparty%2Fkernel%2Fstable.git

regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.

commit d6b41cb06044a7d895db82bdd54f6e4219970510 upstream.

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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index cd5c5bffac87a..7a58be457eb52 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1403,6 +1403,9 @@ int regmap_bulk_write(struct regmap *map, unsigned int reg, const void *val,
 	if (val_bytes == 1) {
 		wval = (void *)val;
 	} else {
+		if (!val_count)
+			return -EINVAL;
+
 		wval = kmemdup(val, val_count * val_bytes, GFP_KERNEL);
 		if (!wval) {
 			ret = -ENOMEM;