Re: [PATCH] Libertas: fix buffer overflow in lbs_get_essid()

Daniel Mack
2009-12-16T23:15:24Z

On Wed, Dec 16, 2009 at 08:57:47AM -0800, Dan Williams wrote:
> On Wed, 2009-12-16 at 05:12 +0100, Daniel Mack wrote:
> > The libertas driver copies the SSID buffer back to the wireless core and
> > appends a trailing NULL character for termination. This is
> >
> > a) unnecessary because the buffer is allocated with kzalloc and is hence
> > already NULLed when this function is called, and
> >
> > b) for priv->curbssparams.ssid_len == 32, it writes back one byte too
> > much which causes memory corruptions.
> >
> > Fix this by removing the extra write.
>
> Acked-by: Dan Williams <dcbw@redhat.com>

Thanks, everyone. Who will care to pick an queue this one?

Daniel

> > Signed-off-by: Daniel Mack <daniel@caiaq.de>
> > Cc: Dan Williams <dcbw@redhat.com>
> > Cc: Holger Schurig <holgerschurig@gmail.com>
> > Cc: John W. Linville <linville@tuxdriver.com>
> > Cc: Stephen Hemminger <shemminger@vyatta.com>
> > Cc: Maithili Hinge <maithili@marvell.com>
> > Cc: Kiran Divekar <dkiran@marvell.com>
> > Cc: Michael Hirsch <m.hirsch@raumfeld.com>
> > Cc: netdev@vger.kernel.org
> > Cc: libertas-dev@lists.infradead.org
> > Cc: linux-wireless@lists.infradead.org
> > Cc: stable@kernel.org
> > ---
> > drivers/net/wireless/libertas/wext.c | 2 --
> > 1 files changed, 0 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/net/wireless/libertas/wext.c b/drivers/net/wireless/libertas/wext.c
> > index be837a0..01c738b 100644
> > --- a/drivers/net/wireless/libertas/wext.c
> > +++ b/drivers/net/wireless/libertas/wext.c
> > @@ -1953,10 +1953,8 @@ static int lbs_get_essid(struct net_device *dev, struct iw_request_info *info,
> > if (priv->connect_status == LBS_CONNECTED) {
> > memcpy(extra, priv->curbssparams.ssid,
> > priv->curbssparams.ssid_len);
> > - extra[priv->curbssparams.ssid_len] = '\0';
> > } else {
> > memset(extra, 0, 32);
> > - extra[priv->curbssparams.ssid_len] = '\0';
> > }
> > /*
> > * If none, we may want to get the one that was set
>