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Message-ID: <d2a4a91d-1b8a-4136-af30-50eb693423df@linaro.org>
Date: Thu, 11 Apr 2024 10:49:03 +0100
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Subject: Re: [PATCH v1 RESEND] slimbus: stream: Add null pointer check for
 client functions
To: Viken Dadhaniya <quic_vdadhani@quicinc.com>, andersson@kernel.org,
 konrad.dybcio@linaro.org, linux-arm-msm@vger.kernel.org,
 alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org
Cc: quic_msavaliy@quicinc.com, quic_vtanuku@quicinc.com,
 quic_anupkulk@quicinc.com, quic_cchiluve@quicinc.com
References: <20240327083214.29443-1-quic_vdadhani@quicinc.com>
Content-Language: en-US
From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
In-Reply-To: <20240327083214.29443-1-quic_vdadhani@quicinc.com>
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Thanks Viken for the patch,

On 27/03/2024 08:32, Viken Dadhaniya wrote:
> There is a possible scenario where client driver is calling
> slimbus stream APIs in incorrect sequence and it might lead to
> invalid null access of the stream pointer in slimbus
> enable/disable/prepare/unprepare/free function.
> 
> Fix this by checking validity of the stream before accessing in
> all function API’s exposed to client.
> 
> Signed-off-by: Viken Dadhaniya <quic_vdadhani@quicinc.com>
> ---
>   drivers/slimbus/stream.c | 37 +++++++++++++++++++++++++++++++++----
>   1 file changed, 33 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/slimbus/stream.c b/drivers/slimbus/stream.c
> index 1d6b38657917..c5a436fd0952 100644
> --- a/drivers/slimbus/stream.c
> +++ b/drivers/slimbus/stream.c
> @@ -202,10 +202,16 @@ static int slim_get_prate_code(int rate)
>   int slim_stream_prepare(struct slim_stream_runtime *rt,
>   			struct slim_stream_config *cfg)
>   {
> -	struct slim_controller *ctrl = rt->dev->ctrl;
> +	struct slim_controller *ctrl;
>   	struct slim_port *port;
>   	int num_ports, i, port_id, prrate;
>   
> +	if (!rt || !cfg) {
> +		pr_err("%s: Stream or cfg is NULL, Check from client side\n", __func__);

Please use dev_err where possible


--srini
> +		return -EINVAL;
> +	}
> +
> +	ctrl = rt->dev->ctrl;
>   	if (rt->ports) {
>   		dev_err(&rt->dev->dev, "Stream already Prepared\n");
>   		return -EINVAL;
> @@ -358,9 +364,15 @@ int slim_stream_enable(struct slim_stream_runtime *stream)
>   {
>   	DEFINE_SLIM_BCAST_TXN(txn, SLIM_MSG_MC_BEGIN_RECONFIGURATION,
>   				3, SLIM_LA_MANAGER, NULL);
> -	struct slim_controller *ctrl = stream->dev->ctrl;
> +	struct slim_controller *ctrl;
>   	int ret, i;
>   
> +	if (!stream) {
> +		pr_err("%s: Stream is NULL, Check from client side\n", __func__);
> +		return -EINVAL;
> +	}
> +
> +	ctrl = stream->dev->ctrl;
>   	if (ctrl->enable_stream) {
>   		ret = ctrl->enable_stream(stream);
>   		if (ret)
> @@ -411,12 +423,18 @@ int slim_stream_disable(struct slim_stream_runtime *stream)
>   {
>   	DEFINE_SLIM_BCAST_TXN(txn, SLIM_MSG_MC_BEGIN_RECONFIGURATION,
>   				3, SLIM_LA_MANAGER, NULL);
> -	struct slim_controller *ctrl = stream->dev->ctrl;
> +	struct slim_controller *ctrl;
>   	int ret, i;
>   
> +	if (!stream) {
> +		pr_err("%s: Stream is NULL, Check from client side\n", __func__);
> +		return -EINVAL;
> +	}
> +
>   	if (!stream->ports || !stream->num_ports)
>   		return -EINVAL;
>   
> +	ctrl = stream->dev->ctrl;
>   	if (ctrl->disable_stream)
>   		ctrl->disable_stream(stream);
>   
> @@ -448,6 +466,11 @@ int slim_stream_unprepare(struct slim_stream_runtime *stream)
>   {
>   	int i;
>   
> +	if (!stream) {
> +		pr_err("%s: Stream is NULL, Check from client side\n", __func__);
> +		return -EINVAL;
> +	}
> +
>   	if (!stream->ports || !stream->num_ports)
>   		return -EINVAL;
>   
> @@ -476,8 +499,14 @@ EXPORT_SYMBOL_GPL(slim_stream_unprepare);
>    */
>   int slim_stream_free(struct slim_stream_runtime *stream)
>   {
> -	struct slim_device *sdev = stream->dev;
> +	struct slim_device *sdev;
> +
> +	if (!stream) {
> +		pr_err("%s: Stream is NULL, Check from client side\n", __func__);
> +		return -EINVAL;
> +	}
>   
> +	sdev = stream->dev;
>   	spin_lock(&sdev->stream_list_lock);
>   	list_del(&stream->node);
>   	spin_unlock(&sdev->stream_list_lock);