[PATCH 5.10.y 10/10] staging: rtl8723bs: fix OOB reads in is_ap_in_tkip() IE loop

[Sasha Levin <sashal@kernel.org>]

From: Alexandru Hossu <hossu.alexandru@gmail.com>

[ Upstream commit 3bf39f711ff27c64be8680a8938bcc5001982e81 ]

The loop in is_ap_in_tkip() iterates over IEs without verifying that
enough bytes remain before dereferencing the IE header or its payload:

- pIE->element_id and pIE->length are read without checking that
  i + sizeof(*pIE) <= ie_length, so a truncated IE at the end of the
  buffer causes an OOB read.

- For WLAN_EID_VENDOR_SPECIFIC the code compares pIE->data + 12,
  which requires pIE->length >= 16.  For WLAN_EID_RSN it compares
  pIE->data + 8, requiring pIE->length >= 12.  Neither requirement
  is checked.

Add the missing IE header and payload bounds checks and guard each
data access with an explicit pIE->length minimum, matching the
pattern established in update_beacon_info().

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable <stable@kernel.org>
Signed-off-by: Alexandru Hossu <hossu.alexandru@gmail.com>
Link: https://patch.msgid.link/20260522004531.1038924-7-hossu.alexandru@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/staging/rtl8723bs/core/rtw_wlan_util.c | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_wlan_util.c b/drivers/staging/rtl8723bs/core/rtw_wlan_util.c
index aa02881f4efe59..38c9ec26ce2962 100644
--- a/drivers/staging/rtl8723bs/core/rtw_wlan_util.c
+++ b/drivers/staging/rtl8723bs/core/rtw_wlan_util.c
@@ -1430,15 +1430,23 @@ unsigned int is_ap_in_tkip(struct adapter *padapter)
 		for (i = sizeof(struct ndis_802_11_fix_ie); i < pmlmeinfo->network.IELength;) {
 			pIE = (struct ndis_80211_var_ie *)(pmlmeinfo->network.IEs + i);
 
+			if (i + 2 > pmlmeinfo->network.IELength)
+				break;
+			if (i + 2 + pIE->length > pmlmeinfo->network.IELength)
+				break;
+
 			switch (pIE->element_id) {
 			case _VENDOR_SPECIFIC_IE_:
-				if ((!memcmp(pIE->data, RTW_WPA_OUI, 4)) && (!memcmp((pIE->data + 12), WPA_TKIP_CIPHER, 4)))
+				if (pIE->length >= 16 &&
+				    !memcmp(pIE->data, RTW_WPA_OUI, 4) &&
+				    !memcmp((pIE->data + 12), WPA_TKIP_CIPHER, 4))
 					return true;
 
 				break;
 
 			case _RSN_IE_2_:
-				if (!memcmp((pIE->data + 8), RSN_TKIP_CIPHER, 4))
+				if (pIE->length >= 12 &&
+				    !memcmp((pIE->data + 8), RSN_TKIP_CIPHER, 4))
 					return true;
 
 			default:
-- 
2.53.0