ibmtr: possible Read buffer overflow?

Prevent read outside array bounds.

Signed-off-by: Roel Kluin <roel.kluin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 2 deletions

diff --git a/drivers/net/tokenring/ibmtr.c b/drivers/net/tokenring/ibmtr.c
index 525bbc5b9c9d..6a3c7510afd9 100644
--- a/drivers/net/tokenring/ibmtr.c
+++ b/drivers/net/tokenring/ibmtr.c
@@ -1143,9 +1143,16 @@ static void dir_open_adapter (struct net_device *dev)
                 } else {
                         char **prphase = printphase;
                         char **prerror = printerror;
+                        int pnr = err / 16 - 1;
+                        int enr = err % 16 - 1;
                         DPRINTK("TR Adapter misc open failure, error code = ");
-                        printk("0x%x, Phase: %s, Error: %s\n",
-                                err, prphase[err/16 -1], prerror[err%16 -1]);
+                        if (pnr < 0 || pnr >= ARRAY_SIZE(printphase) ||
+                                        enr < 0 ||
+                                        enr >= ARRAY_SIZE(printerror))
+                                printk("0x%x, invalid Phase/Error.", err);
+                        else
+                                printk("0x%x, Phase: %s, Error: %s\n", err,
+                                                prphase[pnr], prerror[enr]);
                         printk(" retrying after %ds delay...\n",
                                         TR_RETRY_INTERVAL/HZ);
                 }