On 5/18/22 11:00, Denis Efremov wrote:
> This code has a check to prevent read overflow but it needs another
> check to prevent writing beyond the end of the ->Ssid[] array.
>
> Fixes: 2b42bd58b321 ("staging: r8188eu: introduce new os_dep dir for RTL8188eu driver")
> Cc: stable <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Denis Efremov <denis.e.efremov@xxxxxxxxxx>
> ---
>
> This patch is a copy of Dan's 74b6b20df8cf (CVE-2021-28660).
> Drivers r8188eu and rtl8188eu share the same code.
I also found same code pattern in rtl8723bs driver in
stable kernels 5.10, 5.4, 4.19, 4.14.
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/drivers/staging/rtl8723bs/os_dep/ioctl_linux.c?h=linux-5.10.y#n1354
I can send the same fix to stable trees if appropriate.
>
> drivers/staging/r8188eu/os_dep/ioctl_linux.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/r8188eu/os_dep/ioctl_linux.c b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
> index eb9375b0c660..a2692ce02bc2 100644
> --- a/drivers/staging/r8188eu/os_dep/ioctl_linux.c
> +++ b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
> @@ -1131,9 +1131,11 @@ static int rtw_wx_set_scan(struct net_device *dev, struct iw_request_info *a,
> break;
> }
> 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++;
> }
> pos += sec_len;
