Received-SPF: pass (google.com: domain of linux-kernel+bounces-33869-linux.lists.archive=gmail.com@vger.kernel.org designates 147.75.48.161 as permitted sender) client-ip=147.75.48.161;
Message-ID: <bd8965ec-f2fe-44ae-9b0a-e6aad7a6b7bb@embeddedor.com>
Date: Mon, 22 Jan 2024 11:50:35 -0600
Precedence: bulk
MIME-Version: 1.0
User-Agent: Mozilla Thunderbird
Subject: Re: [PATCH] bus: mhi: ep: Use kcalloc() instead of kzalloc()
Content-Language: en-US
To: Erick Archer <erick.archer@gmx.com>,
 Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>,
 Jeffrey Hugo <quic_jhugo@quicinc.com>, "Rafael J. Wysocki"
 <rafael@kernel.org>, Dan Carpenter <error27@gmail.com>,
 Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
 "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: linux-arm-msm@vger.kernel.org, mhi@lists.linux.dev,
 linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org
References: <20240120152518.13006-1-erick.archer@gmx.com>
From: "Gustavo A. R. Silva" <gustavo@embeddedor.com>
In-Reply-To: <20240120152518.13006-1-erick.archer@gmx.com>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 7bit


On 1/20/24 09:25, Erick Archer wrote:
> As noted in the "Deprecated Interfaces, Language Features, Attributes,
> and Conventions" documentation [1], size calculations (especially
> multiplication) should not be performed in memory allocator (or similar)
> function arguments due to the risk of them overflowing. This could lead
> to values wrapping around and a smaller allocation being made than the
> caller was expecting. Using those allocations could lead to linear
> overflows of heap memory and other misbehaviors.
> 
> So, use the purpose specific kcalloc() function instead of the argument
> count * size in the kzalloc() function.
> 
> Link: https://www.kernel.org/doc/html/next/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments [1]
> Link: https://github.com/KSPP/linux/issues/162
> Signed-off-by: Erick Archer <erick.archer@gmx.com>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks!
-- 
Gustavo

> ---
>   drivers/bus/mhi/ep/main.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
> index 65fc1d738bec..8d7a4102bdb7 100644
> --- a/drivers/bus/mhi/ep/main.c
> +++ b/drivers/bus/mhi/ep/main.c
> @@ -1149,8 +1149,9 @@ int mhi_ep_power_up(struct mhi_ep_cntrl *mhi_cntrl)
>   	mhi_ep_mmio_mask_interrupts(mhi_cntrl);
>   	mhi_ep_mmio_init(mhi_cntrl);
> 
> -	mhi_cntrl->mhi_event = kzalloc(mhi_cntrl->event_rings * (sizeof(*mhi_cntrl->mhi_event)),
> -					GFP_KERNEL);
> +	mhi_cntrl->mhi_event = kcalloc(mhi_cntrl->event_rings,
> +				       sizeof(*mhi_cntrl->mhi_event),
> +				       GFP_KERNEL);
>   	if (!mhi_cntrl->mhi_event)
>   		return -ENOMEM;
> 
> --
> 2.25.1
> 
>