linux-kernel - [PATCH 1/2] base/platform: Safe handling for NULL platform data and resources

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Date:	Tue, 7 Sep 2010 17:31:49 +0400
From:	Anton Vorontsov <cbouatmailru@...il.com>
To:	Greg Kroah-Hartman <gregkh@...e.de>
Cc:	Samuel Ortiz <sameo@...ux.intel.com>,
	Mark Brown <broonie@...nsource.wolfsonmicro.com>,
	linux-kernel@...r.kernel.org
Subject: [PATCH 1/2] base/platform: Safe handling for NULL platform data
 and resources

Some users of platform_device_add_{data,resources}() assume that
NULL data and resources will be handled specially, i.e. just ignored.

But the platform core ends up calling kmemdup(NULL, 0, ...), which
returns a non-NULL result (i.e. ZERO_SIZE_PTR), which causes drivers
to oops on a valid code, something like:

  if (platform_data)
  	stuff = platform_data->stuff;

This patch makes the platform core a bit more safe for such cases.

Signed-off-by: Anton Vorontsov <cbouatmailru@...il.com>
---
 drivers/base/platform.c |    9 ++++++++-
 1 files changed, 8 insertions(+), 1 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index c6c933f..67519cd 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -192,6 +192,9 @@ int platform_device_add_resources(struct platform_device *pdev,
 {
 	struct resource *r;
 
+	if (!res)
+		return 0;
+
 	r = kmemdup(res, sizeof(struct resource) * num, GFP_KERNEL);
 	if (r) {
 		pdev->resource = r;
@@ -215,8 +218,12 @@ EXPORT_SYMBOL_GPL(platform_device_add_resources);
 int platform_device_add_data(struct platform_device *pdev, const void *data,
 			     size_t size)
 {
-	void *d = kmemdup(data, size, GFP_KERNEL);
+	void *d;
+
+	if (!data)
+		return 0;
 
+	d = kmemdup(data, size, GFP_KERNEL);
 	if (d) {
 		pdev->dev.platform_data = d;
 		return 0;
-- 
1.7.0.5

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