2017-03-20 14:47:54

by Colin King

Subject: [PATCH] i40e: fix memcpy with swapped arguments

From: Colin Ian King <[email protected]>

The current code copies an uninitialized params into
cdev->lan_info.params and then passes the uninitialized params
to the call cdev->client->ops->l2_param_change. I believe the
order of the source and destination in the memcpy is the wrong
way around and should be swapped.

Detected with static analysis by cppcheck

Fixes: 0ef2d5afb12d ("i40e: KISS the client interface")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/net/ethernet/intel/i40e/i40e_client.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_client.c b/drivers/net/ethernet/intel/i40e/i40e_client.c
index a9f0d22a7cf4..191580ed946d 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_client.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_client.c
@@ -147,7 +147,7 @@ void i40e_notify_client_of_l2_param_changes(struct i40e_vsi *vsi)
dev_dbg(&vsi->back->pdev->dev, "Client is not open, abort l2 param change\n");
return;
}
- memcpy(&cdev->lan_info.params, &params, sizeof(struct i40e_params));
+ memcpy(&params, &cdev->lan_info.params, sizeof(struct i40e_params));
cdev->client->ops->l2_param_change(&cdev->lan_info, cdev->client,
&params);
}
--
2.11.0

2017-03-20 23:34:17

by Jacob Keller

Subject: RE: [Intel-wired-lan] [PATCH] i40e: fix memcpy with swapped arguments

> -----Original Message-----
> From: Intel-wired-lan [mailto:[email protected]] On
> Behalf Of Colin King
> Sent: Monday, March 20, 2017 7:46 AM
> To: Kirsher, Jeffrey T <[email protected]>; intel-wired-
> [email protected]; [email protected]
> Cc: [email protected]; [email protected]
> Subject: [Intel-wired-lan] [PATCH] i40e: fix memcpy with swapped arguments
>
> From: Colin Ian King <[email protected]>

Hi there,

>
> The current code copies an uninitialized params into
> cdev->lan_info.params and then passes the uninitialized params
> to the call cdev->client->ops->l2_param_change. I believe the
> order of the source and destination in the memcpy is the wrong
> way around and should be swapped.
>

So you are correct that params is uninitialized. However, the fix here is not correct. Somehow we dropped the code for initializing the parameters.

See commit d7ce6422d6e6 ("i40e: don't check params until after checking for client instance", 2017-02-09) It looks like the commit itself was malformed when applied upstream, and a later commit which should have preserved the changes 3140aa9a78c9 ("i40e: KISS the client interface", 2017-03-14) accidentally dropped them.

I'll provide a patch to get this back into the correct state.

Thanks for catching this.

Regards,
Jake