[net-next,05/13] i40e: rework exit flow of i40e_add_fdir_ethtool

Message ID 20170320234712.84157-6-jeffrey.t.kirsher@intel.com
State Accepted
Delegated to: David Miller
Headers show

Commit Message

Jeff Kirsher March 20, 2017, 11:47 p.m.
From: Jacob Keller <jacob.e.keller@intel.com>

Refactor the exit flow of the i40e_add_fdir_ethtool function. Move the
input_label to the end of the function, removing the dependency on
having a non-zero return value. Add a comment explaining why it is ok
not to free the fdir data structure, because the structure is now stored
in the fdir_filter_list.

Change-Id: I723342181d59cd0c9f3b31140c37961ba37bb242
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
---
 drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 15 +++++++++++----
 1 file changed, 11 insertions(+), 4 deletions(-)

Comments

Sergei Shtylyov March 21, 2017, 10:11 a.m. | #1
Hello!

On 3/21/2017 2:47 AM, Jeff Kirsher wrote:

> From: Jacob Keller <jacob.e.keller@intel.com>
>
> Refactor the exit flow of the i40e_add_fdir_ethtool function. Move the
> input_label to the end of the function, removing the dependency on

    I don't see 'input_label' anywhere. Perhaps 'free_input' label was meant?

> having a non-zero return value. Add a comment explaining why it is ok
> not to free the fdir data structure, because the structure is now stored
> in the fdir_filter_list.
>
> Change-Id: I723342181d59cd0c9f3b31140c37961ba37bb242
> Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
> Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
> ---
>  drivers/net/ethernet/intel/i40e/i40e_ethtool.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> index 7a22b473dbdd..d16a5a6b24fc 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
> @@ -2828,12 +2828,19 @@ static int i40e_add_fdir_ethtool(struct i40e_vsi *vsi,
>  	}
>
>  	ret = i40e_add_del_fdir(vsi, input, true);
> -free_input:
>  	if (ret)
> -		kfree(input);
> -	else
> -		i40e_update_ethtool_fdir_entry(vsi, input, fsp->location, NULL);
> +		goto free_input;
> +
> +	/* Add the input filter to the fdir_input_list, possibly replacing
> +	 * a previous filter. Do not free the input structure after adding it
> +	 * to the list as this would cause a use-after-free bug.
> +	 */
> +	i40e_update_ethtool_fdir_entry(vsi, input, fsp->location, NULL);
>
> +	return 0;
> +
> +free_input:
> +	kfree(input);
>  	return ret;
>  }

MBR, Sergei
Keller, Jacob E March 21, 2017, 9:25 p.m. | #2
> -----Original Message-----

> From: Sergei Shtylyov [mailto:sergei.shtylyov@cogentembedded.com]

> Sent: Tuesday, March 21, 2017 3:11 AM

> To: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel.com>; davem@davemloft.net

> Cc: Keller, Jacob E <jacob.e.keller@intel.com>; netdev@vger.kernel.org;

> nhorman@redhat.com; sassmann@redhat.com; jogreene@redhat.com

> Subject: Re: [net-next 05/13] i40e: rework exit flow of i40e_add_fdir_ethtool

> 

> Hello!

> 

> On 3/21/2017 2:47 AM, Jeff Kirsher wrote:

> 

> > From: Jacob Keller <jacob.e.keller@intel.com>

> >

> > Refactor the exit flow of the i40e_add_fdir_ethtool function. Move the

> > input_label to the end of the function, removing the dependency on

> 

>     I don't see 'input_label' anywhere. Perhaps 'free_input' label was meant?

> 


You're correct. 

Thanks,
Jake

Patch

diff --git a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
index 7a22b473dbdd..d16a5a6b24fc 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_ethtool.c
@@ -2828,12 +2828,19 @@  static int i40e_add_fdir_ethtool(struct i40e_vsi *vsi,
 	}
 
 	ret = i40e_add_del_fdir(vsi, input, true);
-free_input:
 	if (ret)
-		kfree(input);
-	else
-		i40e_update_ethtool_fdir_entry(vsi, input, fsp->location, NULL);
+		goto free_input;
+
+	/* Add the input filter to the fdir_input_list, possibly replacing
+	 * a previous filter. Do not free the input structure after adding it
+	 * to the list as this would cause a use-after-free bug.
+	 */
+	i40e_update_ethtool_fdir_entry(vsi, input, fsp->location, NULL);
 
+	return 0;
+
+free_input:
+	kfree(input);
 	return ret;
 }