[PATCH v6] wifi: mt76: Fix NULL Dereference caused by mt76_connac_get_he_phy_cap()

[Gax-c <zichenxie0106@gmail.com>]

From: Zichen Xie <zichenxie0106@gmail.com>

mt76_connac_get_he_phy_cap() may return a NULL pointer,
leading to NULL Pointer Dereference.
Add a NULL check for the returned pointer.

Fixes: a5c372f77aa7 ("wifi: mt76: mt7925: extend mt7925_mcu_bss_he_tlv for per-link BSS")
Fixes: e6d557a78b60 ("mt76: mt7915: rely on mt76_connac_get_phy utilities")
Fixes: 98686cd21624 ("wifi: mt76: mt7996: add driver for MediaTek Wi-Fi 7 (802.11be) devices")
Signed-off-by: Zichen Xie <zichenxie0106@gmail.com>
---
v5: Add version tag.
v6: Adjust NULL check position for readability.
---
 drivers/net/wireless/mediatek/mt76/mt7915/mcu.c | 5 +++++
 drivers/net/wireless/mediatek/mt76/mt7925/mcu.c | 2 ++
 drivers/net/wireless/mediatek/mt76/mt7996/mcu.c | 2 ++
 3 files changed, 9 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
index 87d0dd040001..4d53f819c5f1 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/mcu.c
@@ -551,6 +551,8 @@ mt7915_mcu_bss_he_tlv(struct sk_buff *skb, struct ieee80211_vif *vif,
 	struct tlv *tlv;
 
 	cap = mt76_connac_get_he_phy_cap(phy->mt76, vif);
+	if (!cap)
+		return;
 
 	tlv = mt76_connac_mcu_add_tlv(skb, BSS_INFO_HE_BASIC, sizeof(*he));
 
@@ -1140,6 +1142,9 @@ mt7915_mcu_sta_bfer_he(struct ieee80211_sta *sta, struct ieee80211_vif *vif,
 	struct ieee80211_he_cap_elem *pe = &pc->he_cap_elem;
 	const struct ieee80211_sta_he_cap *vc =
 		mt76_connac_get_he_phy_cap(phy->mt76, vif);
+	if (!vc)
+		return;
+
 	const struct ieee80211_he_cap_elem *ve = &vc->he_cap_elem;
 	u16 mcs_map = le16_to_cpu(pc->he_mcs_nss_supp.rx_mcs_80);
 	u8 nss_mcs = mt7915_mcu_get_sta_nss(mcs_map);
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
index 748ea6adbc6b..55e4cda2f20f 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/mcu.c
@@ -2508,6 +2508,8 @@ mt7925_mcu_bss_he_tlv(struct sk_buff *skb, struct ieee80211_bss_conf *link_conf,
 	struct tlv *tlv;
 
 	cap = mt76_connac_get_he_phy_cap(phy->mt76, link_conf->vif);
+	if (!cap)
+		return;
 
 	tlv = mt76_connac_mcu_add_tlv(skb, UNI_BSS_INFO_HE_BASIC, sizeof(*he));
 
diff --git a/drivers/net/wireless/mediatek/mt76/mt7996/mcu.c b/drivers/net/wireless/mediatek/mt76/mt7996/mcu.c
index 6c445a9dbc03..55bb2d0e67e5 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7996/mcu.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7996/mcu.c
@@ -798,6 +798,8 @@ mt7996_mcu_bss_he_tlv(struct sk_buff *skb, struct ieee80211_vif *vif,
 	struct tlv *tlv;
 
 	cap = mt76_connac_get_he_phy_cap(phy->mt76, vif);
+	if (!cap)
+		return;
 
 	tlv = mt7996_mcu_add_uni_tlv(skb, UNI_BSS_INFO_HE_BASIC, sizeof(*he));
 
-- 
2.25.1