From 6719429dd61cde1fe30d9644d0aa2369eefc9005 Mon Sep 17 00:00:00 2001 From: Luciano Coelho Date: Tue, 12 Feb 2013 20:11:38 +0200 Subject: [PATCH] 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 Signed-off-by: Luciano Coelho [change BUILD_BUG_ON to != 1 (from >= 2)] Signed-off-by: Johannes Berg --- net/wireless/scan.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/net/wireless/scan.c b/net/wireless/scan.c index b7a1679..d0fc6da 100644 --- a/net/wireless/scan.c +++ b/net/wireless/scan.c @@ -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; -- 2.7.4