linux-kernel - [PATCH 3/3] regmap: duplicate the name string stored in regmap

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Message-Id: <20171213092812.26472-4-brgl@bgdev.pl>
Date:   Wed, 13 Dec 2017 10:28:12 +0100
From:   Bartosz Golaszewski <brgl@...ev.pl>
To:     Mark Brown <broonie@...nel.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org, Lars-Peter Clausen <lars@...afoo.de>,
        Andy Shevchenko <andy.shevchenko@...il.com>,
        Bartosz Golaszewski <brgl@...ev.pl>
Subject: [PATCH 3/3] regmap: duplicate the name string stored in regmap

Currently we just copy over the pointer passed to regmap_init() in
the regmap config struct. To be on the safe side: duplicate the string
so that if an unaware user passes an address to a stack-allocated
buffer, we won't crash.

Signed-off-by: Bartosz Golaszewski <brgl@...ev.pl>
---
 drivers/base/regmap/regmap.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index a2a02ce58824..3952e5d7638a 100644
--- a/drivers/base/regmap/regmap.c
+++ b/drivers/base/regmap/regmap.c
@@ -672,6 +672,14 @@ struct regmap *__regmap_init(struct device *dev,
 		goto err;
 	}
 
+	if (config->name) {
+		map->name = kstrdup(config->name, GFP_KERNEL);
+		if (!map->name) {
+			ret = -ENOMEM;
+			goto err_map;
+		}
+	}
+
 	if (config->disable_locking) {
 		map->locking_disabled = true;
 		map->lock = map->unlock = regmap_lock_unlock_none;
@@ -763,7 +771,6 @@ struct regmap *__regmap_init(struct device *dev,
 	map->volatile_reg = config->volatile_reg;
 	map->precious_reg = config->precious_reg;
 	map->cache_type = config->cache_type;
-	map->name = config->name;
 
 	spin_lock_init(&map->async_lock);
 	INIT_LIST_HEAD(&map->async_list);
@@ -1308,6 +1315,7 @@ void regmap_exit(struct regmap *map)
 	}
 	if (map->hwlock)
 		hwspin_lock_free(map->hwlock);
+	kfree(map->name);
 	kfree(map);
 }
 EXPORT_SYMBOL_GPL(regmap_exit);
-- 
2.15.1