RE: [Intel-wired-lan] [PATCH net v2] iavf: validate num_vsis in VIRTCHNL_OP_GET_VF_RESOURCES response

[Loktionov, Aleksandr]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@xxxxxxxxxx> On Behalf
> Of Junrui Luo
> Sent: Thursday, May 14, 2026 8:55 AM
> To: Nguyen, Anthony L <anthony.l.nguyen@xxxxxxxxx>; Kitszel,
> Przemyslaw <przemyslaw.kitszel@xxxxxxxxx>; Andrew Lunn
> <andrew+netdev@xxxxxxx>; David S. Miller <davem@xxxxxxxxxxxxx>; Eric
> Dumazet <edumazet@xxxxxxxxxx>; Jakub Kicinski <kuba@xxxxxxxxxx>; Paolo
> Abeni <pabeni@xxxxxxxxxx>; Mitch Williams
> <mitch.a.williams@xxxxxxxxx>; Greg Rose <gregory.v.rose@xxxxxxxxx>
> Cc: intel-wired-lan@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; Yuhao Jiang <danisjiang@xxxxxxxxx>;
> stable@xxxxxxxxxxxxxxx; Junrui Luo <moonafterrain@xxxxxxxxxxx>
> Subject: [Intel-wired-lan] [PATCH net v2] iavf: validate num_vsis in
> VIRTCHNL_OP_GET_VF_RESOURCES response
> 
> The VF allocates a fixed-size buffer for IAVF_MAX_VF_VSI (3) VSI
> entries when processing a VIRTCHNL_OP_GET_VF_RESOURCES response from
> the PF. However, num_vsis from the PF response is used unchecked as
> the loop bound when iterating over vsi_res[] in multiple functions.
> 
> A PF sending num_vsis greater than IAVF_MAX_VF_VSI, or the received
> message is shorter than num_vsis claims leads to out-of-bounds
> accesses on the vsi_res[] array.
> 
> Clamp num_vsis based on the actual bytes copied from the PF response.
> 
> Fixes: 5eae00c57f5e ("i40evf: main driver core")
> Reported-by: Yuhao Jiang <danisjiang@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Junrui Luo <moonafterrain@xxxxxxxxxxx>
> ---
> Changes in v2:
> - Clamp num_vsis based on actual received message length instead of
> IAVF_MAX_VF_VSI suggested by Przemek
> - Link to v1:
> https://lore.kernel.org/r/SYBPR01MB7881AF11C45AEDC0D4CA89C1AF062@SYBPR
> 01MB7881.ausprd01.prod.outlook.com
> ---
>  drivers/net/ethernet/intel/iavf/iavf_virtchnl.c | 26
> ++++++++++++++++++++-----
>  1 file changed, 21 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
> b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
> index a52c100dcbc5..1f9a2fc70084 100644
> --- a/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
> +++ b/drivers/net/ethernet/intel/iavf/iavf_virtchnl.c
> @@ -248,12 +248,28 @@ int iavf_send_vf_ptp_caps_msg(struct
> iavf_adapter *adapter)
>  /**
>   * iavf_validate_num_queues
>   * @adapter: adapter structure
> + * @msglen: length of the received VF resource message
>   *
> - * Validate that the number of queues the PF has sent in
> - * VIRTCHNL_OP_GET_VF_RESOURCES is not larger than the VF can handle.
> + * Validate the VIRTCHNL_OP_GET_VF_RESOURCES response from the PF.
> + Ensure
> + * num_vsis does not exceed what the message length can cover, and
> cap
> + * num_queue_pairs to the VF maximum.
>   **/
> -static void iavf_validate_num_queues(struct iavf_adapter *adapter)
> +static void iavf_validate_num_queues(struct iavf_adapter *adapter,
> u16
> +msglen)
>  {
> +	u16 max_vsis;
> +
> +	if (msglen < sizeof(struct virtchnl_vf_resource))
> +		max_vsis = 0;
> +	else
> +		max_vsis = (msglen - sizeof(struct
> virtchnl_vf_resource)) /
> +			   sizeof(struct virtchnl_vsi_resource);
> +
> +	if (adapter->vf_res->num_vsis > max_vsis) {
> +		dev_info(&adapter->pdev->dev, "Received %d VSIs, but
> message can only cover %d\n",
> +			 adapter->vf_res->num_vsis, max_vsis);
> +		adapter->vf_res->num_vsis = max_vsis;
> +	}
> +
>  	if (adapter->vf_res->num_queue_pairs > IAVF_MAX_REQ_QUEUES) {
>  		struct virtchnl_vsi_resource *vsi_res;
>  		int i;
> @@ -300,7 +316,7 @@ int iavf_get_vf_config(struct iavf_adapter
> *adapter)
>  	 * we aren't getting too many queues
>  	 */
>  	if (!err)
> -		iavf_validate_num_queues(adapter);
> +		iavf_validate_num_queues(adapter, min(event.msg_len,
> len));
>  	iavf_vf_parse_hw_config(hw, adapter->vf_res);
> 
>  	kfree(event.msg_buf);
> @@ -2609,7 +2625,7 @@ void iavf_virtchnl_completion(struct
> iavf_adapter *adapter,
>  		u16 len = IAVF_VIRTCHNL_VF_RESOURCE_SIZE;
> 
>  		memcpy(adapter->vf_res, msg, min(msglen, len));
> -		iavf_validate_num_queues(adapter);
> +		iavf_validate_num_queues(adapter, min(msglen, len));
>  		iavf_vf_parse_hw_config(&adapter->hw, adapter->vf_res);
>  		if (is_zero_ether_addr(adapter->hw.mac.addr)) {
>  			/* restore current mac address */
> 
> ---
> base-commit: 7aaa8047eafd0bd628065b15757d9b48c5f9c07d
> change-id: 20260514-fixes-a6c4176c0c6a
> 
> Best regards,
> --
> Junrui Luo <moonafterrain@xxxxxxxxxxx>

Reviewed-by: Aleksandr Loktionov <aleksandr.loktionov@xxxxxxxxx>