Commit 4ac2813c authored by Will Deacon's avatar Will Deacon Committed by Johannes Berg
Browse files

cfg80211: wext: avoid copying malformed SSIDs 



Ensure the SSID element is bounds-checked prior to invoking memcpy()
with its length field, when copying to userspace.

Cc: <stable@vger.kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Reported-by: default avatarNicolas Waisman <nico@semmle.com>
Signed-off-by: default avatarWill Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20191004095132.15777-2-will@kernel.org


[adjust commit log a bit]
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 4152561f

net/wireless/wext-sme.c

+6 −2
Original line number Diff line number Diff line
@@ -202,6 +202,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev, 
			       struct iw_point *data, char *ssid)

{

	struct wireless_dev *wdev = dev->ieee80211_ptr;

	int ret = 0;



	/* call only for station! */

	if (WARN_ON(wdev->iftype != NL80211_IFTYPE_STATION))
@@ -219,6 +220,9 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev, 
		if (ie) {

			data->flags = 1;

			data->length = ie[1];

			if (data->length > IW_ESSID_MAX_SIZE)

				ret = -EINVAL;

			else

				memcpy(ssid, ie + 2, data->length);

		}

		rcu_read_unlock();
@@ -229,7 +233,7 @@ int cfg80211_mgd_wext_giwessid(struct net_device *dev, 
	}

	wdev_unlock(wdev);



	return 0;

	return ret;

}



int cfg80211_mgd_wext_siwap(struct net_device *dev,