[PATCH v2] wifi: ath12k: validate MAC/PHY capability count before saving

[Jiale Yao]

Firmware supplies the hardware mode count and the PHY bitmap for each
mode in the service-ready-ext event. ath12k_wmi_save_all_mac_phy_info()
uses those bitmaps to populate svc_ext_info->mac_phy_info, but the
destination is a fixed array of ATH12K_MAX_MAC_PHY_CAP elements.

If the total number of advertised PHY entries exceeds that limit, the
loop writes beyond mac_phy_info and corrupts adjacent memory.

ath12k_wmi_mac_phy_caps_parse() allocates the source array for
tot_phy_id entries and rejects excess capability TLVs. However, if the
event contains fewer capability TLVs than advertised, the remaining
allocated entries stay zeroed and are saved as invalid PHY information.

After parsing the MAC/PHY capability TLVs, validate the destination
capacity and reject an incomplete capability list before saving any
entries.

Fixes: 062ade23991e ("wifi: ath12k: parse and save hardware mode info from WMI_SERVICE_READY_EXT_EVENTID event for later use")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jiale Yao <yaojiale02@xxxxxxx>

---

Changes in v2:
- Refer to the service-ready-ext event.
- Describe a short capability list as a correctness issue instead of a
  source-buffer overrun.
- Move the checks after MAC/PHY capability parsing and use '<' for the
  reachable count mismatch.

diff --git a/drivers/net/wireless/ath/ath12k/wmi.c b/drivers/net/wireless/ath/ath12k/wmi.c
index d5160af60e00..3e812c79a649 100644
--- a/drivers/net/wireless/ath/ath12k/wmi.c
+++ b/drivers/net/wireless/ath/ath12k/wmi.c
@@ -5050,6 +5050,7 @@ static int ath12k_wmi_svc_rdy_ext_parse(struct ath12k_base *ab,
 					u16 tag, u16 len,
 					const void *ptr, void *data)
 {
+	struct ath12k_svc_ext_info *svc_ext_info = &ab->wmi_ab.svc_ext_info;
 	struct ath12k_wmi_pdev *wmi_handle = &ab->wmi_ab.wmi[0];
 	struct ath12k_wmi_svc_rdy_ext_parse *svc_rdy_ext = data;
 	int ret;
@@ -5094,6 +5095,22 @@ static int ath12k_wmi_svc_rdy_ext_parse(struct ath12k_base *ab,
 				return ret;
 			}
 
+			if (svc_rdy_ext->tot_phy_id >
+			    ARRAY_SIZE(svc_ext_info->mac_phy_info)) {
+				ath12k_warn(ab, "too many PHY entries %u (max %zu)\n",
+					    svc_rdy_ext->tot_phy_id,
+					    ARRAY_SIZE(svc_ext_info->mac_phy_info));
+				return -EINVAL;
+			}
+
+			if (svc_rdy_ext->n_mac_phy_caps < svc_rdy_ext->tot_phy_id) {
+				ath12k_warn(ab,
+					    "not enough MAC/PHY caps %u, expected %u\n",
+					    svc_rdy_ext->n_mac_phy_caps,
+					    svc_rdy_ext->tot_phy_id);
+				return -EINVAL;
+			}
+
 			ath12k_wmi_save_all_mac_phy_info(ab, svc_rdy_ext);
 
 			svc_rdy_ext->mac_phy_done = true;
-- 
2.34.1