ethernet: hisilicon: hns: hns_dsaf_misc: fix a possible array overflow in hns_dsaf_ge...

The if statement:
  if (port >= DSAF_GE_NUM)
        return;

limits the value of port less than DSAF_GE_NUM (i.e., 8).
However, if the value of port is 6 or 7, an array overflow could occur:
  port_rst_off = dsaf_dev->mac_cb[port]->port_rst_off;

because the length of dsaf_dev->mac_cb is DSAF_MAX_PORT_NUM (i.e., 6).

To fix this possible array overflow, we first check port and if it is
greater than or equal to DSAF_MAX_PORT_NUM, the function returns.

Reported-by: TOTE Robot <oslab@tsinghua.edu.cn>
Signed-off-by: Teng Qi <starmiku1207184332@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c
index 23d9cbf..740850b 100644 (file)
--- a/drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c
+++ b/drivers/net/ethernet/hisilicon/hns/hns_dsaf_misc.c
@@ -400,6 +400,10 @@ static void hns_dsaf_ge_srst_by_port(struct dsaf_device *dsaf_dev, u32 port,
                return;
 
        if (!HNS_DSAF_IS_DEBUG(dsaf_dev)) {
+               /* DSAF_MAX_PORT_NUM is 6, but DSAF_GE_NUM is 8.
+                  We need check to prevent array overflow */
+               if (port >= DSAF_MAX_PORT_NUM)
+                       return;
                reg_val_1  = 0x1 << port;
                port_rst_off = dsaf_dev->mac_cb[port]->port_rst_off;
                /* there is difference between V1 and V2 in register.*/