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From: Alex Elder <elder@linaro.org>
To: Dan Carpenter <error27@gmail.com>,
	Manivannan Sadhasivam <mani@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jeffrey Hugo <quic_jhugo@quicinc.com>,
	mhi@lists.linux.dev, linux-arm-msm@vger.kernel.org,
	kernel-janitors@vger.kernel.org
Subject: Re: [PATCH] bus: mhi: ep: Fix off by one in mhi_ep_process_cmd_ring()
Date: Thu, 26 Jan 2023 07:26:32 -0600	[thread overview]
Message-ID: <b1891679-9a0d-2327-4e6a-e3dd262ca233@linaro.org> (raw)
In-Reply-To: <Y9JH5sudiZWvbODv@kili>

On 1/26/23 3:29 AM, Dan Carpenter wrote:
> The > comparison should be changed to >= to prevent an out of bounds
> access into the mhi_cntrl->mhi_chan[] array.  The mhi_cntrl->mhi_chan[]
> array is allocated in mhi_ep_chan_init() and has mhi_cntrl->max_chan
> elements.

You're right.  I scanned through that file and there
are other spots that don't check that the channel ID
is in range, though I think this is the one where it's
reading it from an external source.  I.e., the other
places are aleady known to be correct.  (Maybe Mani
can comment.)

Reviewed-by: Alex Elder <elder@linaro.org>

> 
> Fixes: 2527ad44ddb2 ("bus: mhi: ep: Check if the channel is supported by the controller")
> Signed-off-by: Dan Carpenter <error27@gmail.com>
> ---
>   drivers/bus/mhi/ep/main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/mhi/ep/main.c b/drivers/bus/mhi/ep/main.c
> index bcaaba97ef63..be2d56e7f392 100644
> --- a/drivers/bus/mhi/ep/main.c
> +++ b/drivers/bus/mhi/ep/main.c
> @@ -125,7 +125,7 @@ static int mhi_ep_process_cmd_ring(struct mhi_ep_ring *ring, struct mhi_ring_ele
>   	ch_id = MHI_TRE_GET_CMD_CHID(el);
>   
>   	/* Check if the channel is supported by the controller */
> -	if ((ch_id > mhi_cntrl->max_chan) || !mhi_cntrl->mhi_chan[ch_id].name) {
> +	if ((ch_id >= mhi_cntrl->max_chan) || !mhi_cntrl->mhi_chan[ch_id].name) {
>   		dev_err(dev, "Channel (%u) not supported!\n", ch_id);
>   		return -ENODEV;
>   	}


  reply	other threads:[~2023-01-26 13:26 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-26  9:29 [PATCH] bus: mhi: ep: Fix off by one in mhi_ep_process_cmd_ring() Dan Carpenter
2023-01-26 13:26 ` Alex Elder [this message]
2023-01-27  6:48   ` Manivannan Sadhasivam
2023-01-27  6:46 ` Manivannan Sadhasivam
2023-01-27  6:59 ` Manivannan Sadhasivam

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