[PATCH v2 4/5] staging: rtl8723bs: fix out-of-bounds check in rtw_restruct_wmm_ie

[Luka Gejak <lukagejak5@gmail.com>]

Add a length check before accessing the OUI in WMM
IE to prevent potential out-of-bounds reads.
Use memcmp() for better readability.

Fixes: 554c0a3abf21 ("staging: Add rtl8723bs sdio wifi driver")

Signed-off-by: Luka Gejak <lukagejak5@gmail.com>
---
 drivers/staging/rtl8723bs/core/rtw_mlme.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8723bs/core/rtw_mlme.c b/drivers/staging/rtl8723bs/core/rtw_mlme.c
index c4f58106b3bd..18a70879f78f 100644
--- a/drivers/staging/rtl8723bs/core/rtw_mlme.c
+++ b/drivers/staging/rtl8723bs/core/rtw_mlme.c
@@ -2000,7 +2000,8 @@ int rtw_restruct_wmm_ie(struct adapter *adapter, u8 *in_ie, u8 *out_ie, uint in_
 	while (i < in_len) {
 		ielength = initial_out_len;
 
-		if (in_ie[i] == 0xDD && in_ie[i+2] == 0x00 && in_ie[i+3] == 0x50  && in_ie[i+4] == 0xF2 && in_ie[i+5] == 0x02 && i+5 < in_len) { /* WMM element ID and OUI */
+		if (i + 5 < in_len && in_ie[i] == 0xDD &&
+		!memcmp(&in_ie[i + 2], "\x00\x50\xf2\x02", 4)) {
 			for (j = i; j < i + 9; j++) {
 				out_ie[ielength] = in_ie[j];
 				ielength++;
-- 
2.52.0