linux-kernel - Applied "regmap: potentially duplicate the name string stored in regmap" to the regmap tree

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Date:   Wed, 13 Dec 2017 19:42:50 +0000
From:   Mark Brown <broonie@...nel.org>
To:     Bartosz Golaszewski <brgl@...ev.pl>
Cc:     Mark Brown <broonie@...nel.org>, linux-kernel@...r.kernel.org
Subject: Applied "regmap: potentially duplicate the name string stored in regmap" to the regmap tree

The patch

   regmap: potentially duplicate the name string stored in regmap

has been applied to the regmap tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regmap.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 8253bb3f82554cedb830a4cb65c84796df129c81 Mon Sep 17 00:00:00 2001
From: Bartosz Golaszewski <brgl@...ev.pl>
Date: Wed, 13 Dec 2017 17:25:31 +0100
Subject: [PATCH] regmap: potentially 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
with kstrdup_const() 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>
Signed-off-by: Mark Brown <broonie@...nel.org>
---
 drivers/base/regmap/regmap.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/base/regmap/regmap.c b/drivers/base/regmap/regmap.c
index 496da7bc5e77..84b5784e171b 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_const(config->name, GFP_KERNEL);
+		if (!map->name) {
+			ret = -ENOMEM;
+			goto err_map;
+		}
+	}
+
 	if (config->disable_locking) {
 		map->lock = map->unlock = regmap_lock_unlock_none;
 		regmap_debugfs_disable(map);
@@ -683,7 +691,7 @@ struct regmap *__regmap_init(struct device *dev,
 		map->hwlock = hwspin_lock_request_specific(config->hwlock_id);
 		if (!map->hwlock) {
 			ret = -ENXIO;
-			goto err_map;
+			goto err_name;
 		}
 
 		switch (config->hwlock_mode) {
@@ -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);
@@ -1119,6 +1126,8 @@ struct regmap *__regmap_init(struct device *dev,
 err_hwlock:
 	if (map->hwlock)
 		hwspin_lock_free(map->hwlock);
+err_name:
+	kfree_const(map->name);
 err_map:
 	kfree(map);
 err:
@@ -1308,6 +1317,7 @@ void regmap_exit(struct regmap *map)
 	}
 	if (map->hwlock)
 		hwspin_lock_free(map->hwlock);
+	kfree_const(map->name);
 	kfree(map);
 }
 EXPORT_SYMBOL_GPL(regmap_exit);
-- 
2.15.1