[PATCH] wifi: mwifiex: validate HT/VHT capability and operation IE lengths

[Doruk Tan Ozturk <doruk@0sec.ai>]

mwifiex_update_bss_desc_with_ie() records raw pointers to the HT
Capabilities, HT Operation, VHT Capabilities, VHT Operation, 20/40 BSS
Coexistence and Operating Mode Notification elements taken straight out
of a beacon/probe-response buffer, without checking that each element is
long enough for the fixed-size structure that later consumers read. The
buffer is a tight kmemdup() of the on-air IEs (beacon_buf_size ==
ies->len), so a truncated element placed last leaves the stored pointer
one past the end of the allocation.

At association time these pointers are dereferenced at fixed offsets
regardless of the on-air length: mwifiex_cmd_append_11n_tlv() memcpy()s
sizeof(struct ieee80211_ht_cap) (26 bytes) from bcn_ht_cap and reads
bcn_ht_oper->ht_param, and mwifiex_cmd_append_11ac_tlv() memcpy()s
sizeof(struct ieee80211_vht_cap) (12 bytes) from bcn_vht_cap and reads
bcn_vht_oper->chan_width. A nearby AP (rogue / evil-twin; an open SSID
needs no credentials) advertising a BSS with a truncated HT/VHT cap
element therefore triggers a slab out-of-bounds read on the victim's
association attempt. This out-of-bounds read is the primary issue.

For the HT-Cap copy the over-read bytes are additionally placed into the
outgoing association request, so a limited amount of adjacent heap memory
can leak over the air. In station mode this is small (single-digit
bytes), because mwifiex_fill_cap_info() rewrites most of the copied
HT-Cap before transmission; the leak is a secondary effect.

mwifiex_set_sta_ht_cap() has the same missing-length pattern: in uAP mode
it reads two bytes of ieee80211_ht_cap.cap_info from a
cfg80211_find_ie(WLAN_EID_HT_CAPABILITY) result in a client association
request without checking the element length, a 1-2 byte out-of-bounds
read (used only to select an A-MSDU size, not leaked).

Reject (skip) any of these elements whose payload is shorter than the
structure the driver later reads, matching the length validation the
FH/DS/CF/IBSS parameter-set cases in the same beacon parser already
perform.

No dynamic reproducer: mwifiex is a fullmac driver for Marvell hardware
with no mac80211_hwsim equivalent, so this was confirmed by source and
structure-offset analysis only.

Found by 0sec automated security-research tooling (https://0sec.ai).

Fixes: 5e6e3a92b9a4 ("wireless: mwifiex: initial commit for Marvell mwifiex driver")
Cc: stable@vger.kernel.org
Assisted-by: 0sec:claude-opus-4-8
Signed-off-by: Doruk Tan Ozturk <doruk@0sec.ai>
---
 drivers/net/wireless/marvell/mwifiex/scan.c | 12 ++++++++++++
 drivers/net/wireless/marvell/mwifiex/util.c |  2 +-
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c
index 97c0ec3b822e..997e7e19525b 100644
--- a/drivers/net/wireless/marvell/mwifiex/scan.c
+++ b/drivers/net/wireless/marvell/mwifiex/scan.c
@@ -1384,6 +1384,8 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter,
 							bss_entry->beacon_buf);
 			break;
 		case WLAN_EID_HT_CAPABILITY:
+			if (element_len < sizeof(struct ieee80211_ht_cap))
+				break;
 			bss_entry->bcn_ht_cap = (struct ieee80211_ht_cap *)
 					(current_ptr +
 					sizeof(struct ieee_types_header));
@@ -1392,6 +1394,8 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter,
 					bss_entry->beacon_buf);
 			break;
 		case WLAN_EID_HT_OPERATION:
+			if (element_len < sizeof(struct ieee80211_ht_operation))
+				break;
 			bss_entry->bcn_ht_oper =
 				(struct ieee80211_ht_operation *)(current_ptr +
 					sizeof(struct ieee_types_header));
@@ -1400,6 +1404,8 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter,
 					bss_entry->beacon_buf);
 			break;
 		case WLAN_EID_VHT_CAPABILITY:
+			if (element_len < sizeof(struct ieee80211_vht_cap))
+				break;
 			bss_entry->disable_11ac = false;
 			bss_entry->bcn_vht_cap =
 				(void *)(current_ptr +
@@ -1409,6 +1415,8 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter,
 					      bss_entry->beacon_buf);
 			break;
 		case WLAN_EID_VHT_OPERATION:
+			if (element_len < sizeof(struct ieee80211_vht_operation))
+				break;
 			bss_entry->bcn_vht_oper =
 				(void *)(current_ptr +
 					 sizeof(struct ieee_types_header));
@@ -1417,6 +1425,8 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter,
 					      bss_entry->beacon_buf);
 			break;
 		case WLAN_EID_BSS_COEX_2040:
+			if (!element_len)
+				break;
 			bss_entry->bcn_bss_co_2040 = current_ptr;
 			bss_entry->bss_co_2040_offset =
 				(u16) (current_ptr - bss_entry->beacon_buf);
@@ -1427,6 +1437,8 @@ int mwifiex_update_bss_desc_with_ie(struct mwifiex_adapter *adapter,
 				(u16) (current_ptr - bss_entry->beacon_buf);
 			break;
 		case WLAN_EID_OPMODE_NOTIF:
+			if (!element_len)
+				break;
 			bss_entry->oper_mode = (void *)current_ptr;
 			bss_entry->oper_mode_offset =
 					(u16)((u8 *)bss_entry->oper_mode -
diff --git a/drivers/net/wireless/marvell/mwifiex/util.c b/drivers/net/wireless/marvell/mwifiex/util.c
index 7d3631d21223..844223c04e2e 100644
--- a/drivers/net/wireless/marvell/mwifiex/util.c
+++ b/drivers/net/wireless/marvell/mwifiex/util.c
@@ -721,7 +721,7 @@ mwifiex_set_sta_ht_cap(struct mwifiex_private *priv, const u8 *ies,
 
 	ht_cap_ie = (void *)cfg80211_find_ie(WLAN_EID_HT_CAPABILITY, ies,
 					     ies_len);
-	if (ht_cap_ie) {
+	if (ht_cap_ie && ht_cap_ie->len >= sizeof(struct ieee80211_ht_cap)) {
 		ht_cap = (void *)(ht_cap_ie + 1);
 		node->is_11n_enabled = 1;
 		node->max_amsdu = le16_to_cpu(ht_cap->cap_info) &
-- 
2.43.0