[PATCH 6.1 225/609] staging: rtl8723bs: fix OOB reads in rtw_get_wps_ie()

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Moksh Panicker <[email protected]>

commit 0e95ff792ae0aa6fbad9455943e9e1e4062670e9 upstream.

rtw_get_wps_ie() iterates over IE data from network frames without
validating that the IE header and payload fit within the remaining
buffer before reading them. Specifically:

- in_ie[cnt + 1] is read without checking cnt + 1 < in_len
- memcmp(&in_ie[cnt + 2], ...) accesses cnt + 2 without bounds check
- in_ie[cnt + 1] is used as length without verifying payload fits

Add bounds checks at the top of the loop body to break early if fewer
than 2 bytes remain for the IE header, or if the declared payload
extends past the end of the buffer. Also require at least 4 bytes of
payload before comparing the WPS OUI.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")
Cc: stable <[email protected]>
Signed-off-by: Moksh Panicker <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
 drivers/staging/rtl8723bs/core/rtw_ieee80211.c |    9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

--- a/drivers/staging/rtl8723bs/core/rtw_ieee80211.c
+++ b/drivers/staging/rtl8723bs/core/rtw_ieee80211.c
@@ -678,7 +678,14 @@ u8 *rtw_get_wps_ie(u8 *in_ie, uint in_le
 	while (cnt < in_len) {
 		eid = in_ie[cnt];
 
-		if ((eid == WLAN_EID_VENDOR_SPECIFIC) && (!memcmp(&in_ie[cnt + 2], wps_oui, 4))) {
+		if (cnt + 2 > in_len)
+			break;
+
+		if (in_ie[cnt + 1] + 2 > in_len - cnt)
+			break;
+
+		if ((eid == WLAN_EID_VENDOR_SPECIFIC) && (in_ie[cnt + 1] >= 4) &&
+		    (!memcmp(&in_ie[cnt + 2], wps_oui, 4))) {
 			wpsie_ptr = &in_ie[cnt];
 
 			if (wps_ie)