net: phy: mdio-bcm-unimac: fix potential NULL dereference in unimac_mdio_probe()

CVE-2018-8043

platform_get_resource() may fail and return NULL, so we should
better check it's return value to avoid a NULL pointer dereference
a bit later in the code.

This is detected by Coccinelle semantic patch.

@@
expression pdev, res, n, t, e, e1, e2;
@@

res = platform_get_resource(pdev, t, n);
+ if (!res)
+   return -EINVAL;
... when != res == NULL
e = devm_ioremap(e1, res->start, e2);

Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 297a6961ffb8ff4dc66c9fbf53b924bd1dda05d5)
Signed-off-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Acked-by: Khaled Elmously <khalid.elmously@canonical.com>
Acked-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com>
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>

diff --git a/drivers/net/phy/mdio-bcm-unimac.c b/drivers/net/phy/mdio-bcm-unimac.c
index 34395230ce709bd68ba93ca46eff089bb576668f..17003bcf265cb7d4510a88cb2ab7e6435c71ca13 100644 (file)
--- a/drivers/net/phy/mdio-bcm-unimac.c
+++ b/drivers/net/phy/mdio-bcm-unimac.c
@@ -177,6 +177,8 @@ static int unimac_mdio_probe(struct platform_device *pdev)
                return -ENOMEM;
 
        r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+       if (!r)
+               return -EINVAL;
 
        /* Just ioremap, as this MDIO block is usually integrated into an
         * Ethernet MAC controller register range