Subject: Re: [PATCH v3] i40e: Add checking for null for nlmsg_find_attr()

From: Tony Nguyen <[email-masked]>
Date: Thu, 2 Feb 2023 09:23:09 -0800

On 2/1/2023 1:06 AM, Natalia Petrova wrote:
> The result of nlmsg_find_attr() 'br_spec' is dereferenced in
> nla_for_each_nested(), but it can take NULL value in nla_find() function,
> which will result in an error.
> 
> Found by Linux Verification Center (linuxtesting.org) with SVACE.
> 
> Fixes: 51616018dd1b ("i40e: Add support for getlink, setlink ndo ops")
> Signed-off-by: Natalia Petrova <[email-masked]>
> Reviewed-by: Jesse Brandeburg <[email-masked]>
> ---

Thanks for the patch. I've applied it, however, for the future if you 
could specify the target tree. Simon mentioned it in v2, but his example 
omitted the tree.

i.e.
[PATCH v3 net] i40e: Add checking for null for nlmsg_find_attr()

Thanks,
Tony

> v3: Fixed mailing list.
> v2: The remark about the error code by Simon Horman <[email-masked]>
> was taken into account; return value -ENOENT was changed to -EINVAL.
>   drivers/net/ethernet/intel/i40e/i40e_main.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
> index 53d0083e35da..4626d2a1af91 100644
> --- a/drivers/net/ethernet/intel/i40e/i40e_main.c
> +++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
> @@ -13167,6 +13167,8 @@ static int i40e_ndo_bridge_setlink(struct net_device *dev,
>   	}
>   
>   	br_spec = nlmsg_find_attr(nlh, sizeof(struct ifinfomsg), IFLA_AF_SPEC);
> +	if (!br_spec)
> +		return -EINVAL;
>   
>   	nla_for_each_nested(attr, br_spec, rem) {
>   		__u16 mode;