[PATCH 39/97] Libertas: fix buffer overflow in lbs_get_essid()

[Greg Kroah-Hartman]

From: Daniel Mack <daniel@xxxxxxxx>

commit 45b241689179a6065384260242637cf21dabfb2d upstream.

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@xxxxxxxx>
Cc: Stephen Hemminger <shemminger@xxxxxxxxxx>
Cc: Maithili Hinge <maithili@xxxxxxxxxxx>
Cc: Kiran Divekar <dkiran@xxxxxxxxxxx>
Cc: Michael Hirsch <m.hirsch@xxxxxxxxxxxx>
Cc: netdev@xxxxxxxxxxxxxxx
Cc: libertas-dev@xxxxxxxxxxxxxxxxxxx
Cc: linux-wireless@xxxxxxxxxxxxxxxxxxx
Acked-by: Holger Schurig <holgerschurig@xxxxxxxxx>
Acked-by: Dan Williams <dcbw@xxxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 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
-- 
1.6.6

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