Re: [Intel-wired-lan] [PATCH net] idpf: fix double free and use-after-free in aux device error paths

[Paul Menzel <pmenzel@molgen.mpg.de>]

Dear Greg,


Thank you for the patch.

Am 11.04.26 um 12:12 schrieb Greg Kroah-Hartman:
> When auxiliary_device_add() fails in idpf_plug_vport_aux_dev() or
> idpf_plug_core_aux_dev(), the err_aux_dev_add label calls
> auxiliary_device_uninit() and falls through to err_aux_dev_init.  The
> uninit call will trigger put_device(), which invokes the release
> callback (idpf_vport_adev_release / idpf_core_adev_release) that frees
> iadev.  The fall-through then reads adev->id from the freed iadev for
> ida_free() and double-frees iadev with kfree().
> 
> Free the IDA slot and clear the back-pointer before uninit, while adev
> is still valid, then return immediately.
> 
> Commit 65637c3a1811 65637c3a1811 ("idpf: fix UAF in RDMA core aux dev

The commit hash is pasted twice.

> deinitialization") fixed the same use-after-free in the matching unplug
> path in this file but missed both probe error paths.
> 
> Cc: Tony Nguyen <anthony.l.nguyen@intel.com>
> Cc: Przemek Kitszel <przemyslaw.kitszel@intel.com>
> Cc: Andrew Lunn <andrew+netdev@lunn.ch>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Eric Dumazet <edumazet@google.com>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Paolo Abeni <pabeni@redhat.com>
> Cc: stable <stable@kernel.org>
> Fixes: be91128c579c ("idpf: implement RDMA vport auxiliary dev create, init, and destroy")
> Fixes: f4312e6bfa2a ("idpf: implement core RDMA auxiliary dev create, init, and destroy")
> Assisted-by: gregkh_clanker_t1000
> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> ---
> Note, these cleanup paths are messy, but I couldn't see a simpler way
> without a lot more rework, so I choose the simple way :)
> 
>   drivers/net/ethernet/intel/idpf/idpf_idc.c | 6 ++++++
>   1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/idpf/idpf_idc.c b/drivers/net/ethernet/intel/idpf/idpf_idc.c
> index 7e4f4ac92653..b7d6b08fc89e 100644
> --- a/drivers/net/ethernet/intel/idpf/idpf_idc.c
> +++ b/drivers/net/ethernet/intel/idpf/idpf_idc.c
> @@ -90,7 +90,10 @@ static int idpf_plug_vport_aux_dev(struct iidc_rdma_core_dev_info *cdev_info,
>   	return 0;
>   
>   err_aux_dev_add:
> +	ida_free(&idpf_idc_ida, adev->id);
> +	vdev_info->adev = NULL;
>   	auxiliary_device_uninit(adev);
> +	return ret;
>   err_aux_dev_init:
>   	ida_free(&idpf_idc_ida, adev->id);
>   err_ida_alloc:
> @@ -228,7 +231,10 @@ static int idpf_plug_core_aux_dev(struct iidc_rdma_core_dev_info *cdev_info)
>   	return 0;
>   
>   err_aux_dev_add:
> +	ida_free(&idpf_idc_ida, adev->id);
> +	cdev_info->adev = NULL;
>   	auxiliary_device_uninit(adev);
> +	return ret;
>   err_aux_dev_init:
>   	ida_free(&idpf_idc_ida, adev->id);
>   err_ida_alloc:

Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>

gemini/gemini-3.1-pro-preview has two comments [1]. Maybe the driver 
developers could judge their relevance.


Kind regards,

Paul


[1]: 
https://sashiko.dev/#/patchset/2026041116-retail-bagginess-250f%40gregkh