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staging: rtl8723bs: fix OOB read in update_beacon_info() IE loop

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commit ed51de4a86 upstream.

The IE parsing loop in update_beacon_info() advances by
(pIE->length + 2) each iteration but only guards on i < len.
When a malicious AP sends a Beacon whose last IE has only one byte
remaining in the frame (the element_id byte lands at len-1), the loop
reads pIE->length from 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 len, 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 len.

Also replace i += (pIE->length + 2) with i += sizeof(*pIE) + pIE->length
for consistency with the sizeof(*pIE) guards added above.

Fixes: 554c0a3abf ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable <stable@kernel.org>
Reviewed-by: Luka Gejak <luka.gejak@linux.dev>
Signed-off-by: Alexandru Hossu <hossu.alexandru@gmail.com>
Link: https://patch.msgid.link/20260522004531.1038924-2-hossu.alexandru@gmail.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexandru Hossu
2026-07-24 16:02:44 +02:00
committed by Greg Kroah-Hartman
parent 0406d74657
commit 9193c34f75
1 changed files with 5 additions and 1 deletions
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drivers/staging/rtl8723bs/core/rtw_wlan_util.c
+5 -1
View File
@@ -1332,7 +1332,11 @@ void update_beacon_info(struct adapter *padapter, u8 *pframe, uint pkt_len, stru
len = pkt_len - (_BEACON_IE_OFFSET_ + WLAN_HDR_A3_LEN);
for (i = 0; i < len;) {
if (i + sizeof(*pIE) > len)
break;
pIE = (struct ndis_80211_var_ie *)(pframe + (_BEACON_IE_OFFSET_ + WLAN_HDR_A3_LEN) + i);
if (i + sizeof(*pIE) + pIE->length > len)
break;
switch (pIE->element_id) {
case WLAN_EID_VENDOR_SPECIFIC:
@@ -1357,7 +1361,7 @@ void update_beacon_info(struct adapter *padapter, u8 *pframe, uint pkt_len, stru
break;
}
i += (pIE->length + 2);
i += sizeof(*pIE) + pIE->length;
}
}