[PATCH 3.13 058/105] regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.

Kamal Mostafa
2014-10-27T19:01:29Z

From: Xiubo Li <Li.Xiubo@freescale.com>

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: Kamal Mostafa <kamal@canonical.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 1ac3c9a..ebe332c 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -1529,6 +1529,9 @@ 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;
--
1.9.1