Re: staging: possible buffer overflow in rtw_wx_set_scan function in driver/staging/rtl8723bs

[Greg KH]

On Tue, Aug 24, 2021 at 03:04:04PM +0800, iLifetruth wrote:
> Here are the fixes and the contents of the patch file we suggest.
> 
> [PATCH]staging: rtl8723bs: prevent ->ssid overflow in rtw_wx_set_scan()
> 
> This fixing patch is ported from the upstream commit
> 74b6b20df8cf(staging: rtl8188eu: prevent ->ssid overflow in
> rtw_wx_set_scan()) which fixes on another driver numbered rtl8188eu.
> This code has a check to prevent read overflow but it needs another
> check to prevent writing beyond the end of the ->ssid[] array in
> driver rtl8723bs.
> 
> ---
>  drivers/staging/rtl8723bs/os_dep/ioctl_linux.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> index f95000df8942..3b859b71bf43 100644
> --- a/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> +++ b/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c
> @@ -1222,9 +1222,9 @@ static int rtw_wx_set_scan(struct net_device
> *dev, struct iw_request_info *a,
> 
>                                 sec_len = *(pos++); len -= 1;
> 
> -                               if (sec_len > 0 && sec_len <= len) {
> +                               if (sec_len > 0 && sec_len <= len &&
> sec_len<= 32) {
>                                         ssid[ssid_index].SsidLength = sec_len;
> -                                       memcpy(ssid[ssid_index].Ssid,
> pos, ssid[ssid_index].SsidLength);
> +                                       memcpy(ssid[ssid_index].Ssid,
> pos, sec_len);
>                                         ssid_index++;
>                                 }
> 
> --

Hi,

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