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| author | Eric Dumazet <eric.dumazet@gmail.com> | 2009-11-06 00:23:01 +0000 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2009-11-08 00:33:43 -0800 |
| commit | 6755aebaaf9fc5416acfd4578ab7a1e122ecbc74 (patch) | |
| tree | 09f23419b097b15e7c36954cb98bdf28cdfa5af1 /net | |
| parent | cc05368c52fed7d9efa0f56c5270e95bb569713e (diff) | |
| download | lwn-6755aebaaf9fc5416acfd4578ab7a1e122ecbc74.tar.gz lwn-6755aebaaf9fc5416acfd4578ab7a1e122ecbc74.zip | |
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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/can/bcm.c | 19 |
1 files changed, 12 insertions, 7 deletions
diff --git a/net/can/bcm.c b/net/can/bcm.c index 597da4f8f888..e8d58f33fe09 100644 --- a/net/can/bcm.c +++ b/net/can/bcm.c @@ -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) |