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

On Thu, Jan 29, 2026 at 02:23:51PM +0100, Luka Gejak wrote:
> Add a length check before accessing the OUI in WMM
> IE to prevent potential out-of-bounds reads.

Is this really a bugfix?  if so, it needs to go first, and be tagged for
stable trees.

> 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)) {

Very odd indentation :(

Also, why invert the i+5 check?  And the memcmp check is now messier
than the original.

And is that where you are saying this is a security fix?  If so, it's
just a read, not a write, so what is the security issue?

thanks,

greg k-h