[PATCH 3.17 032/146] regmap: fix possible ZERO_SIZE_PTR pointer dereferencing error.

From: Greg Kroah-Hartman
Date: Tue Oct 28 2014 - 04:00:24 EST


3.17-stable review patch. If anyone has any objections, please let me know.

------------------

From: Xiubo Li <Li.Xiubo@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/base/regmap/regmap.c | 3 +++
1 file changed, 3 insertions(+)

--- 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");


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