From 24900688ee47071aa6a61e78473999b5b80f0423 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 [ Upstream commit 80fda1cd7b0a1edd0849dc71403a070d0922118d ] 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 Signed-off-by: Sasha Levin --- 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 35d9673ec0d8..8fa16f95e6a7 100644 --- a/drivers/net/wireless/mediatek/mt76/mt7996/mac.c +++ b/drivers/net/wireless/mediatek/mt76/mt7996/mac.c @@ -650,6 +650,14 @@ mt7996_mac_fill_rx(struct mt7996_dev *dev, struct sk_buff *skb) 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))