Re: [PATCH v4] s390/pkey: Fix memory leak in error case by using memdup_user() rather than open coding

From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Markus Elfring <Markus.Elfring@web.de>,
	linux-s390@vger.kernel.org,
	Harald Freudenberger <freude@linux.ibm.com>,
	Heiko Carstens <heiko.carstens@de.ibm.com>,
	Ingo Franzki <ifranzki@linux.ibm.com>,
	Vasily Gorbik <gor@linux.ibm.com>, Joe Perches <joe@perches.com>
Cc: LKML <linux-kernel@vger.kernel.org>,
	kernel-janitors@vger.kernel.org, Kangjie Lu <kjlu@umn.edu>,
	Navid Emamdoost <emamd001@umn.edu>,
	Stephen McCamant <smccaman@umn.edu>
Subject: Re: [PATCH v4] s390/pkey: Fix memory leak in error case by using memdup_user() rather than open coding
Date: Mon, 11 Nov 2019 17:40:52 +0100	[thread overview]
Message-ID: <0c47ee47-35a0-65ee-4da1-e1745f882947@de.ibm.com> (raw)
In-Reply-To: <aca044e8-e4b2-eda8-d724-b08772a44ed9@web.de>

On 11.11.19 15:45, Markus Elfring wrote:
> Date: Mon, 11 Nov 2019 15:20:44 +0100
> 
> Reuse existing functionality from memdup_user() instead of keeping
> duplicate source code.
> 
> Generated by: scripts/coccinelle/api/memdup_user.cocci
> 
> * The function "_copy_apqns_from_user" contained a memory leak
>   because of a misssing function call "kfree(kapqns)" for an if branch.
>   Link: https://lore.kernel.org/r/833d7d5e-6ede-6bdd-a2cc-2da7f0b03908@de.ibm.com/
> 
>   Thus complete the exception handling by this code replacement.
> 
> * Delete local variables which became unnecessary with this refactoring
>   in two function implementations.
> 
> Fixes: f2bbc96e7cfad3891b7bf9bd3e566b9b7ab4553d ("s390/pkey: add CCA AES cipher key support")
> Signed-off-by: Markus Elfring <Markus.Elfring@web.de>
> ---
> 
> v4:
> Further changes were requested by Christian Bornträger.
> https://lore.kernel.org/r/040f3e18-d97a-fc32-b237-20e7553e1733@de.ibm.com/
> 
> * An other patch subject was selected.
> 
> * An other email address was used for the tag “Signed-off-by” this time.

applied. [...]

> +	if (!uapqns || nr_apqns <= 0)

While applying I changed that to 
	if (!uapqns || nr_apqns == 0)

as nr_apqns is size_t and thus unsigned. 