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authorVladislav Efanov <VEfanov@ispras.ru>2023-05-26 19:16:32 +0300
committerSimon Wunderlich <sw@simonwunderlich.de>2023-05-26 23:14:49 +0200
commitabac3ac97fe8734b620e7322a116450d7f90aa43 (patch)
tree286962a4c0dd2977a5f1594df9cb30de180e6026 /net/batman-adv
parent44c026a73be8038f03dbdeef028b642880cf1511 (diff)
batman-adv: Broken sync while rescheduling delayed work
Syzkaller got a lot of crashes like: KASAN: use-after-free Write in *_timers* All of these crashes point to the same memory area: The buggy address belongs to the object at ffff88801f870000 which belongs to the cache kmalloc-8k of size 8192 The buggy address is located 5320 bytes inside of 8192-byte region [ffff88801f870000, ffff88801f872000) This area belongs to : batadv_priv->batadv_priv_dat->delayed_work->timer_list The reason for these issues is the lack of synchronization. Delayed work (batadv_dat_purge) schedules new timer/work while the device is being deleted. As the result new timer/delayed work is set after cancel_delayed_work_sync() was called. So after the device is freed the timer list contains pointer to already freed memory. Found by Linux Verification Center (linuxtesting.org) with syzkaller. Cc: stable@kernel.org Fixes: 2f1dfbe18507 ("batman-adv: Distributed ARP Table - implement local storage") Signed-off-by: Vladislav Efanov <VEfanov@ispras.ru> Acked-by: Sven Eckelmann <sven@narfation.org> Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Diffstat (limited to 'net/batman-adv')
-rw-r--r--net/batman-adv/distributed-arp-table.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/batman-adv/distributed-arp-table.c b/net/batman-adv/distributed-arp-table.c
index 6968e55eb971..28a939d56090 100644
--- a/net/batman-adv/distributed-arp-table.c
+++ b/net/batman-adv/distributed-arp-table.c
@@ -101,7 +101,6 @@ static void batadv_dat_purge(struct work_struct *work);
*/
static void batadv_dat_start_timer(struct batadv_priv *bat_priv)
{
- INIT_DELAYED_WORK(&bat_priv->dat.work, batadv_dat_purge);
queue_delayed_work(batadv_event_workqueue, &bat_priv->dat.work,
msecs_to_jiffies(10000));
}
@@ -819,6 +818,7 @@ int batadv_dat_init(struct batadv_priv *bat_priv)
if (!bat_priv->dat.hash)
return -ENOMEM;
+ INIT_DELAYED_WORK(&bat_priv->dat.work, batadv_dat_purge);
batadv_dat_start_timer(bat_priv);
batadv_tvlv_handler_register(bat_priv, batadv_dat_tvlv_ogm_handler_v1,