bonding: fix a buffer overflow in bonding_show_queue_id.

The test for buffer overflow ensures we have room for 6 more bytes.
sprintf, called with %s:%d, slave->dev->name, slave->queue_id may yield
far more than 6 bytes.

The correct test is res > (PAGE_SIZE - IFNAMSIZ - 6) .

Signed-off-by: Nicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index f9a0343..1a99764 100644 (file)
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -1427,8 +1427,8 @@ static ssize_t bonding_show_queue_id(struct device *d,
 
        read_lock(&bond->lock);
        bond_for_each_slave(bond, slave, i) {
-               if (res > (PAGE_SIZE - 6)) {
-                       /* not enough space for another interface name */
+               if (res > (PAGE_SIZE - IFNAMSIZ - 6)) {
+                       /* not enough space for another interface_name:queue_id pair */
                        if ((PAGE_SIZE - res) > 10)
                                res = PAGE_SIZE - 10;
                        res += sprintf(buf + res, "++more++ ");