On Mon, 2010-08-30 at 11:03 -0700, Kees Cook wrote:

Hi Johannes,

On Mon, Aug 30, 2010 at 12:24:54PM +0200, Johannes Berg wrote:

quoted

--- wireless-testing.orig/net/wireless/wext-compat.c	2010-08-30 12:04:57.000000000 +0200
+++ wireless-testing/net/wireless/wext-compat.c	2010-08-30 12:11:32.000000000 +0200

@@ -1420,6 +1420,9 @@ int cfg80211_wext_giwessid(struct net_de
 {
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 
+	data->flags = 0;
+	data->length = 0;
+
 	switch (wdev->iftype) {
 	case NL80211_IFTYPE_ADHOC:
 		return cfg80211_ibss_wext_giwessid(dev, info, data, ssid);

Thanks for all your work on this! Were you able to trigger the leak
through cfg80211? If so, then this will need a CVE assigned and sent to
stable too, I think.

Yes, I was, very easily, by doing an SIOCGIWESSID while unassociated,
with a large iwq->length set by userspace. I did CC stable on my patch,
but we can amend the commit by a CVE if so desired.

johannes