From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752175AbdLMJct (ORCPT ); Wed, 13 Dec 2017 04:32:49 -0500 Received: from www381.your-server.de ([78.46.137.84]:53950 "EHLO www381.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751641AbdLMJcq (ORCPT ); Wed, 13 Dec 2017 04:32:46 -0500 Subject: Re: [PATCH 3/3] regmap: duplicate the name string stored in regmap To: Bartosz Golaszewski , Mark Brown , Greg Kroah-Hartman Cc: linux-kernel@vger.kernel.org, Andy Shevchenko References: <20171213092812.26472-1-brgl@bgdev.pl> <20171213092812.26472-4-brgl@bgdev.pl> From: Lars-Peter Clausen Message-ID: Date: Wed, 13 Dec 2017 10:32:39 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <20171213092812.26472-4-brgl@bgdev.pl> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: lars@metafoo.de Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/13/2017 10:28 AM, Bartosz Golaszewski wrote: > 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 > --- > 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); To get the best of both worlds: kstrdup_const(), this will not make a copy when it is in a read-only section (like most strings will be). Needs to be matched with kfree_const(). > + 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); >