staging: r8188eu: prevent ->Ssid overflow in rtw_wx_set_scan()

commit bc10916e890948d8927a5c8c40fb5dc44be5e1b8 upstream.

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@vger.kernel.org>
Signed-off-by: Denis Efremov <denis.e.efremov@oracle.com>
Link: https://lore.kernel.org/r/20220518070052.108287-1-denis.e.efremov@oracle.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/r8188eu/os_dep/ioctl_linux.c b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
index 41b457838a5ba36eac77f83213c3d9580c93ce75..2a1bd66dabfa10e578347331c67b2c7c36f391cc 100644 (file)
--- a/drivers/staging/r8188eu/os_dep/ioctl_linux.c
+++ b/drivers/staging/r8188eu/os_dep/ioctl_linux.c
@@ -1181,9 +1181,11 @@ 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;