linux-kernel - Re: [PATCH V2] cfg80211: Fix possible memory leak in function cfg80211_bss

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Message-ID: <YQKELjKuAQsjmpLY@kroah.com>
Date:   Thu, 29 Jul 2021 12:34:22 +0200
From:   Greg KH <greg@...ah.com>
To:     Nguyen Dinh Phi <phind.uet@...il.com>
Cc:     johannes@...solutions.net, davem@...emloft.net, kuba@...nel.org,
        netdev@...r.kernel.org, linux-wireless@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        linux-kernel-mentees@...ts.linuxfoundation.org
Subject: Re: [PATCH V2] cfg80211: Fix possible memory leak in function
 cfg80211_bss_update

On Mon, Jun 28, 2021 at 09:23:34PM +0800, Nguyen Dinh Phi wrote:
> When we exceed the limit of BSS entries, this function will free the
> new entry, however, at this time, it is the last door to access the
> inputed ies, so these ies will be unreferenced objects and cause memory
> leak.
> Therefore we should free its ies before deallocating the new entry, beside
> of dropping it from hidden_list.
> 
> Signed-off-by: Nguyen Dinh Phi <phind.uet@...il.com>
> ---
> V2:	- Add subsystem to the subject line.
> 	- Use bss_ref_put function for better clean-up dynamically allocated
> 	cfg80211_internal_bss objects. It helps to clean relative hidden_bss.
> 
>  net/wireless/scan.c | 6 ++----
>  1 file changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/net/wireless/scan.c b/net/wireless/scan.c
> index f03c7ac8e184..7897b1478c3c 100644
> --- a/net/wireless/scan.c
> +++ b/net/wireless/scan.c
> @@ -1754,16 +1754,14 @@ cfg80211_bss_update(struct cfg80211_registered_device *rdev,
>  			 * be grouped with this beacon for updates ...
>  			 */
>  			if (!cfg80211_combine_bsses(rdev, new)) {
> -				kfree(new);
> +				bss_ref_put(rdev, new);
>  				goto drop;
>  			}
>  		}
> 
>  		if (rdev->bss_entries >= bss_entries_limit &&
>  		    !cfg80211_bss_expire_oldest(rdev)) {
> -			if (!list_empty(&new->hidden_list))
> -				list_del(&new->hidden_list);
> -			kfree(new);
> +			bss_ref_put(rdev, new);
>  			goto drop;
>  		}
> 
> --
> 2.25.1

Did this change get lost somewhere?

thanks,

greg k-h