From 80fda1cd7b0a1edd0849dc71403a070d0922118d Mon Sep 17 00:00:00 2001 From: Benjamin Lin Date: Thu, 15 May 2025 11:29:47 +0800 Subject: [PATCH] wifi: mt76: mt7996: drop fragments with multicast or broadcast RA 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 Signed-off-by: Shayne Chen Link: https://patch.msgid.link/20250515032952.1653494-4-shayne.chen@mediatek.com Signed-off-by: Felix Fietkau --- 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)) -- 2.50.1