netfilter: nft_compat: destroy function must not have side effects
The nft_compat destroy function deletes the nft_xt object from a list.
This isn't allowed anymore. Destroy functions are called asynchronously,
i.e. next batch can find the object that has a pending ->destroy()
invocation:
cpu0 cpu1
worker
->destroy for_each_entry()
if (x == ...
return x->ops;
list_del(x)
kfree_rcu(x)
expr->ops->... // ops was free'd
To resolve this, the list_del needs to occur before the transaction
mutex gets released. nf_tables has a 'deactivate' hook for this
purpose, so use that to unlink the object from the list.
Fixes: 0935d5588400 ("netfilter: nf_tables: asynchronous release")
Reported-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
1 file changed
