From: Benjamin Lin <benjamin-jw.lin@xxxxxxxxxxxx>
IEEE 802.11 fragmentation can only be applied to unicast frames.
Therefore, drop fragments with multicast or broadcast RA. This patch
addresses vulnerabilities such as CVE-2020-26145.
Signed-off-by: Benjamin Lin <benjamin-jw.lin@xxxxxxxxxxxx>
Signed-off-by: Shayne Chen <shayne.chen@xxxxxxxxxxxx>
---
drivers/net/wireless/mediatek/mt76/mt7996/mac.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
index 771c16e8d10c..0dbd4662bc84 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c
@@ -647,6 +647,14 @@ mt7996_mac_fill_rx(struct mt7996_dev *dev, enum mt76_rxq_id q,
status->last_amsdu = amsdu_info == MT_RXD4_LAST_AMSDU_FRAME;
}
+ /* IEEE 802.11 fragmentation can only be applied to unicast frames.
+ * Hence, drop fragments with multicast/broadcast RA.
+ * This check fixes vulnerabilities, like CVE-2020-26145.
+ */
+ if ((ieee80211_has_morefrags(fc) || seq_ctrl & IEEE80211_SCTL_FRAG) &&
+ FIELD_GET(MT_RXD3_NORMAL_ADDR_TYPE, rxd3) != MT_RXD3_NORMAL_U2M)
+ return -EINVAL;
+
hdr_gap = (u8 *)rxd - skb->data + 2 * remove_pad;
if (hdr_trans && ieee80211_has_morefrags(fc)) {
if (mt7996_reverse_frag0_hdr_trans(skb, hdr_gap))
--
2.39.2
