net: dsa: Test array index before use

commit 8f5063e97f393d49611151d3cf7dcbeb41397f12 upstream.

port_index is used an index into an array, and this information comes
from Device Tree, make sure that port_index is not equal to the array
size before using it. Move the check against port_index earlier in the
loop.

Fixes: 5e95329b701c: ("dsa: add device tree bindings to register DSA switches")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>

diff --git a/net/dsa/dsa.c b/net/dsa/dsa.c
index 5db37cef50a9ccd80c642118f54dd4ecf04219b8..d3ca32dc167f2f5e847ed6e2116ec20b3f1262d6 100644 (file)
--- a/net/dsa/dsa.c
+++ b/net/dsa/dsa.c
@@ -427,6 +427,8 @@ static int dsa_of_probe(struct platform_device *pdev)
                                continue;
 
                        port_index = be32_to_cpup(port_reg);
+                       if (port_index >= DSA_MAX_PORTS)
+                               break;
 
                        port_name = of_get_property(port, "label", NULL);
                        if (!port_name)
@@ -449,8 +451,6 @@ static int dsa_of_probe(struct platform_device *pdev)
                                        goto out_free_chip;
                        }
 
-                       if (port_index == DSA_MAX_PORTS)
-                               break;
                }
        }