[PATCH v2 2/2] staging: rtl8723bs: fix OOB read in OnAssocRsp() IE loop

Alexandru Hossu
2026-04-27T08:19:51Z

The IE parsing loop in OnAssocRsp() advances by (pIE->length + 2) each
iteration but only guards on i < pkt_len. When a malicious AP sends an
AssocResponse whose last IE has only one byte remaining in the frame
(the element_id byte lands at pkt_len-1), the loop reads pIE->length
from pframe[pkt_len], which is one byte past the allocated receive buffer.

Additionally, even when the header bytes are in bounds, pIE->length
itself can extend the data window beyond pkt_len, silently passing a
truncated IE to the handler functions.

Add two guards at the top of the loop body:
1. Break if fewer than sizeof(*pIE) bytes remain (can't read header).
2. Break if the IE's declared data extends past pkt_len.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable@vger.kernel.org
Signed-off-by: Alexandru Hossu <hossu.alexandru@gmail.com>
---
drivers/staging/rtl8723bs/core/rtw_mlme_ext.c | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c b/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
index c646dc2a1741..68ce422305ed 100644
--- a/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
+++ b/drivers/staging/rtl8723bs/core/rtw_mlme_ext.c
@@ -1406,7 +1406,11 @@ unsigned int OnAssocRsp(struct adapter *padapter, union recv_frame *precv_frame)
/* to handle HT, WMM, rate adaptive, update MAC reg */
/* for not to handle the synchronous IO in the tasklet */
for (i = (6 + WLAN_HDR_A3_LEN); i < pkt_len;) {
+ if (i + sizeof(*pIE) > pkt_len)
+ break;
pIE = (struct ndis_80211_var_ie *)(pframe + i);
+ if (i + sizeof(*pIE) + pIE->length > pkt_len)
+ break;

switch (pIE->element_id) {
case WLAN_EID_VENDOR_SPECIFIC:
--
2.53.0