can: should not use __dev_get_by_index() without locks
bcm_proc_getifname() is called with RTNL and dev_base_lock
not held. It calls __dev_get_by_index() without locks, and
this is illegal (might crash)
Close the race by holding dev_base_lock and copying dev->name
in the protected section.
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Oliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/can/bcm.c b/net/can/bcm.c
index 597da4f..e8d58f3 100644
--- a/net/can/bcm.c
+++ b/net/can/bcm.c
@@ -132,23 +132,27 @@
/*
* procfs functions
*/
-static char *bcm_proc_getifname(int ifindex)
+static char *bcm_proc_getifname(char *result, int ifindex)
{
struct net_device *dev;
if (!ifindex)
return "any";
- /* no usage counting */
+ read_lock(&dev_base_lock);
dev = __dev_get_by_index(&init_net, ifindex);
if (dev)
- return dev->name;
+ strcpy(result, dev->name);
+ else
+ strcpy(result, "???");
+ read_unlock(&dev_base_lock);
- return "???";
+ return result;
}
static int bcm_proc_show(struct seq_file *m, void *v)
{
+ char ifname[IFNAMSIZ];
struct sock *sk = (struct sock *)m->private;
struct bcm_sock *bo = bcm_sk(sk);
struct bcm_op *op;
@@ -157,7 +161,7 @@
seq_printf(m, " / sk %p", sk);
seq_printf(m, " / bo %p", bo);
seq_printf(m, " / dropped %lu", bo->dropped_usr_msgs);
- seq_printf(m, " / bound %s", bcm_proc_getifname(bo->ifindex));
+ seq_printf(m, " / bound %s", bcm_proc_getifname(ifname, bo->ifindex));
seq_printf(m, " <<<\n");
list_for_each_entry(op, &bo->rx_ops, list) {
@@ -169,7 +173,7 @@
continue;
seq_printf(m, "rx_op: %03X %-5s ",
- op->can_id, bcm_proc_getifname(op->ifindex));
+ op->can_id, bcm_proc_getifname(ifname, op->ifindex));
seq_printf(m, "[%d]%c ", op->nframes,
(op->flags & RX_CHECK_DLC)?'d':' ');
if (op->kt_ival1.tv64)
@@ -194,7 +198,8 @@
list_for_each_entry(op, &bo->tx_ops, list) {
seq_printf(m, "tx_op: %03X %s [%d] ",
- op->can_id, bcm_proc_getifname(op->ifindex),
+ op->can_id,
+ bcm_proc_getifname(ifname, op->ifindex),
op->nframes);
if (op->kt_ival1.tv64)