Commit 6755aeba authored by Eric Dumazet's avatar Eric Dumazet Committed by David S. Miller
Browse files

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: default avatarEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: default avatarOliver Hartkopp <oliver@hartkopp.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cc05368c
......@@ -132,23 +132,27 @@ static inline struct bcm_sock *bcm_sk(const struct sock *sk)
/*
* 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 @@ static int bcm_proc_show(struct seq_file *m, void *v)
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 @@ static int bcm_proc_show(struct seq_file *m, void *v)
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 @@ static int bcm_proc_show(struct seq_file *m, void *v)
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)
......
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