Commit 6719429d authored Feb 12, 2013 by Luciano Coelho Committed by Johannes Berg Feb 13, 2013

cfg80211: check vendor IE length to avoid overrun



cfg80211_find_vendor_ie() was checking only that the vendor IE would
fit in the remaining IEs buffer.  If a corrupt includes a vendor IE
that is too small, we could potentially overrun the IEs buffer.

Fix this by checking that the vendor IE fits in the reported IE length
field and skip it otherwise.

Reported-by: Jouni Malinen <j@w1.fi>
Signed-off-by: Luciano Coelho <coelho@ti.com>
[change BUILD_BUG_ON to != 1 (from >= 2)]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

parent bb92d199

net/wireless/scan.c

+8 −4

Original line number	Diff line number	Diff line
		@@ -365,14 +365,18 @@ const u8 *cfg80211_find_vendor_ie(unsigned int oui, u8 oui_type,
		if (!pos)
		return NULL;

		if (end - pos < sizeof(*ie))
		return NULL;

		ie = (struct ieee80211_vendor_ie *)pos;

		/* make sure we can access ie->len */
		BUILD_BUG_ON(offsetof(struct ieee80211_vendor_ie, len) != 1);

		if (ie->len < sizeof(*ie))
		goto cont;

		ie_oui = ie->oui[0] << 16 \| ie->oui[1] << 8 \| ie->oui[2];
		if (ie_oui == oui && ie->oui_type == oui_type)
		return pos;

		cont:
		pos += 2 + ie->len;
		}
		return NULL;