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

Daniel Mack
2009-12-16T04:13:35Z

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.

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
--
1.6.3.3