[PATCH] Staging: prevent rtl8187se from crashing dev_ioctl() inSIOCGIWNAME

[Dan Aloni]

I repeatedly get __stack_chk_fail panic()s with this driver before
applying the attached fix.

ieee80211_wx_get_name() ignores sizeof(wrqu->name) which is IFNAMSIZ (16), and
on certain conditions, the concatenated string will be larger than IFNAMSIZ
including the terminating zero.

    length ("802.11" ++ "b" ++ "/g" ++ " linked" ++ "\x00") == 17

This fix uses strl{cpy,cat} in addition to the reduction of the total
possible length of the output string by a char.

It can be applied to 2.6.30-stable as well.

Signed-off-by: Dan Aloni <dan@xxxxxxxxx>
---
 .../rtl8187se/ieee80211/ieee80211_softmac_wx.c     |   12 ++++++------
 1 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/staging/rtl8187se/ieee80211/ieee80211_softmac_wx.c b/drivers/staging/rtl8187se/ieee80211/ieee80211_softmac_wx.c
index 93af37e..54b4b71 100644
--- a/drivers/staging/rtl8187se/ieee80211/ieee80211_softmac_wx.c
+++ b/drivers/staging/rtl8187se/ieee80211/ieee80211_softmac_wx.c
@@ -461,19 +461,19 @@ int ieee80211_wx_get_name(struct ieee80211_device *ieee,
 			     struct iw_request_info *info,
 			     union iwreq_data *wrqu, char *extra)
 {
-	strcpy(wrqu->name, "802.11");
+	strlcpy(wrqu->name, "802.11", IFNAMSIZ);
 	if(ieee->modulation & IEEE80211_CCK_MODULATION){
-		strcat(wrqu->name, "b");
+		strlcat(wrqu->name, "b", IFNAMSIZ);
 		if(ieee->modulation & IEEE80211_OFDM_MODULATION)
-			strcat(wrqu->name, "/g");
+			strlcat(wrqu->name, "/g", IFNAMSIZ);
 	}else if(ieee->modulation & IEEE80211_OFDM_MODULATION)
-		strcat(wrqu->name, "g");
+		strlcat(wrqu->name, "g", IFNAMSIZ);
 
 	if((ieee->state == IEEE80211_LINKED) ||
 		(ieee->state == IEEE80211_LINKED_SCANNING))
-		strcat(wrqu->name," linked");
+		strlcat(wrqu->name,"  link", IFNAMSIZ);
 	else if(ieee->state != IEEE80211_NOLINK)
-		strcat(wrqu->name," link..");
+		strlcat(wrqu->name," .....", IFNAMSIZ);
 
 
 	return 0;
-- 
1.6.0.4

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