Re: [PATCH v3 2/2] staging: rtl8723bs: fix OOB read in OnAssocRsp() IE loop

[Luka Gejak]

On April 28, 2026 11:16:21 AM GMT+02:00, Alexandru Hossu <hossu.alexandru@xxxxxxxxx> wrote:
>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@xxxxxxxxxxxxxxx
>Signed-off-by: Alexandru Hossu <hossu.alexandru@xxxxxxxxx>
>---
> 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:

LGTM,

Reviewed-by: Luka Gejak <luka.gejak@xxxxxxxxx>

Best regards,
Luka Gejak