From: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
[ Upstream commit f8017317cb0b279b8ab98b0f3901a2e0ac880dad ]
When IPv6 module gets initialized but hits an error in the middle,
kenel panic with:
KASAN: null-ptr-deref in range [0x0000000000000598-0x000000000000059f]
CPU: 1 PID: 361 Comm: insmod
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
RIP: 0010:__neigh_ifdown.isra.0+0x24b/0x370
RSP: 0018:ffff888012677908 EFLAGS: 00000202
...
Call Trace:
<TASK>
neigh_table_clear+0x94/0x2d0
ndisc_cleanup+0x27/0x40 [ipv6]
inet6_init+0x21c/0x2cb [ipv6]
do_one_initcall+0xd3/0x4d0
do_init_module+0x1ae/0x670
...
Kernel panic - not syncing: Fatal exception
When ipv6 initialization fails, it will try to cleanup and calls:
neigh_table_clear()
neigh_ifdown(tbl, NULL)
pneigh_queue_purge(&tbl->proxy_queue, dev_net(dev == NULL))
# dev_net(NULL) triggers null-ptr-deref.
Fix it by passing NULL to pneigh_queue_purge() in neigh_ifdown() if dev
is NULL, to make kernel not panic immediately.
Fixes: 66ba215cb513 ("neigh: fix possible DoS due to net iface start/stop loop")
Signed-off-by: Chen Zhongjin <chenzhongjin@xxxxxxxxxx>
Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
Reviewed-by: Denis V. Lunev <den@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20221101121552.21890-1-chenzhongjin@xxxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
net/core/neighbour.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 434c5aab83ea..f6f580e9d282 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -373,7 +373,7 @@ static int __neigh_ifdown(struct neigh_table *tbl, struct net_device *dev,
write_lock_bh(&tbl->lock);
neigh_flush_dev(tbl, dev, skip_perm);
pneigh_ifdown_and_unlock(tbl, dev);
- pneigh_queue_purge(&tbl->proxy_queue, dev_net(dev));
+ pneigh_queue_purge(&tbl->proxy_queue, dev ? dev_net(dev) : NULL);
if (skb_queue_empty_lockless(&tbl->proxy_queue))
del_timer_sync(&tbl->proxy_timer);
return 0;
--
2.35.1
