Messages in this thread |  | | From | Julian Calaby <> | Date | Mon, 7 Jan 2013 14:03:10 +1100 | Subject | Re: [PATCH] drivers/net/wireless/mwl8k.c: avoid use-after-free |
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Hi Lennert,
On Mon, Jan 7, 2013 at 1:48 PM, Lennert Buytenhek <buytenh@wantstofly.org> wrote: > On Sun, Jan 06, 2013 at 08:27:22PM -0500, Nickolai Zeldovich wrote: > >> Do not dereference p->station_id after kfree(cmd) because p >> points into the cmd data structure. > > Good catch, but the patch would be better titled "mwl8k.c: avoid > having a working driver", as the station_id return code _is_ needed > by the caller in case of success.
Are you sure?
>> diff --git a/drivers/net/wireless/mwl8k.c b/drivers/net/wireless/mwl8k.c >> index f221b95..83564d3 100644 >> --- a/drivers/net/wireless/mwl8k.c >> +++ b/drivers/net/wireless/mwl8k.c >> @@ -4250,9 +4250,11 @@ static int mwl8k_cmd_update_stadb_add(struct ieee80211_hw *hw, >> p->amsdu_enabled = 0; >> >> rc = mwl8k_post_cmd(hw, &cmd->header); >> + if (!rc) >> + rc = p->station_id; >> kfree(cmd); >> >> - return rc ? rc : p->station_id;
If I'm reading this right, the removed line is equivalent to:
if( rc ) return rc; else return p->station_id;
which is equivalent to:
if( !rc ) rc = p->station_id;
return rc;
Thanks,
-- Julian Calaby
Email: julian.calaby@gmail.com Profile: http://www.google.com/profiles/julian.calaby/ .Plan: http://sites.google.com/site/juliancalaby/
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