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authorChen Zhongjin <chenzhongjin@huawei.com>2022-11-01 20:15:52 +0800
committerJakub Kicinski <kuba@kernel.org>2022-11-02 20:44:27 -0700
commitf8017317cb0b279b8ab98b0f3901a2e0ac880dad (patch)
treef839663564156b80ef5ddd79302b722dd3b2ba27 /net
parent62ff373da2534534c55debe6c724c7fe14adb97f (diff)
net, neigh: Fix null-ptr-deref in neigh_table_clear()
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@huawei.com> Reviewed-by: Eric Dumazet <edumazet@google.com> Reviewed-by: Denis V. Lunev <den@openvz.org> Link: https://lore.kernel.org/r/20221101121552.21890-1-chenzhongjin@huawei.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net')
-rw-r--r--net/core/neighbour.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 3c4786b99907..a77a85e357e0 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -409,7 +409,7 @@ 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;