Re: [Intel-wired-lan] [PATCH v2 iwl-next] ice: Fix some null pointer dereference issues in ice_ptp.c

From: Przemek Kitszel <przemyslaw.kitszel@intel.com>
To: Kunwu Chan <chentao@kylinos.cn>, <jesse.brandeburg@intel.com>,
	<anthony.l.nguyen@intel.com>, <davem@davemloft.net>,
	<edumazet@google.com>, <kuba@kernel.org>, <pabeni@redhat.com>,
	<richardcochran@gmail.com>, <jacob.e.keller@intel.com>
Cc: michal.michalik@intel.com, Kunwu Chan <kunwu.chan@hotmail.com>,
	netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	karol.kolacinski@intel.com, intel-wired-lan@lists.osuosl.org
Subject: Re: [Intel-wired-lan] [PATCH v2 iwl-next] ice: Fix some null pointer dereference issues in ice_ptp.c
Date: Wed, 13 Dec 2023 10:49:10 +0100	[thread overview]
Message-ID: <1abd6bcb-6f6c-10a7-9b6f-e5e038233af8@intel.com> (raw)
In-Reply-To: <20231212024015.11595-1-chentao@kylinos.cn>

On 12/12/23 03:40, Kunwu Chan wrote:
> devm_kasprintf() returns a pointer to dynamically allocated memory
> which can be NULL upon failure.
> 
> Fixes: d938a8cca88a ("ice: Auxbus devices & driver for E822 TS")
> Cc: Kunwu Chan <kunwu.chan@hotmail.com>
> Suggested-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>

You found the bug (or some some static analysis tool in that case);
there is no need to add Suggested-by for every person that suggests
something during review - the tag is for "person/s that suggested
making such change in the repo".

Subject line would be better if less generic, eg:
ice: avoid null deref of ptp auxbus name

> Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
> ---
>   drivers/net/ethernet/intel/ice/ice_ptp.c | 4 ++++
>   1 file changed, 4 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/ice/ice_ptp.c b/drivers/net/ethernet/intel/ice/ice_ptp.c
> index e9e59f4b5580..848e3e063e64 100644
> --- a/drivers/net/ethernet/intel/ice/ice_ptp.c
> +++ b/drivers/net/ethernet/intel/ice/ice_ptp.c
> @@ -2743,6 +2743,8 @@ static int ice_ptp_register_auxbus_driver(struct ice_pf *pf)
>   	name = devm_kasprintf(dev, GFP_KERNEL, "ptp_aux_dev_%u_%u_clk%u",
>   			      pf->pdev->bus->number, PCI_SLOT(pf->pdev->devfn),
>   			      ice_get_ptp_src_clock_index(&pf->hw));
> +	if (!name)
> +		return -ENOMEM;
>   
>   	aux_driver->name = name;
>   	aux_driver->shutdown = ice_ptp_auxbus_shutdown;
> @@ -2989,6 +2991,8 @@ static int ice_ptp_create_auxbus_device(struct ice_pf *pf)
>   	name = devm_kasprintf(dev, GFP_KERNEL, "ptp_aux_dev_%u_%u_clk%u",
>   			      pf->pdev->bus->number, PCI_SLOT(pf->pdev->devfn),
>   			      ice_get_ptp_src_clock_index(&pf->hw));
> +	if (!name)
> +		return -ENOMEM;
>   
>   	aux_dev->name = name;
>   	aux_dev->id = id;

Reviewed-by: Przemek Kitszel <przemyslaw.kitszel@intel.com>

Regarding iwl-next vs iwl-net: this bug is really unlikely to manifest,
as we take care of both earlier and future mem allocs for ptp auxbus,
and auxiliary_device_init() checks for null name, so no big deal,
so: -next is fine
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