netdev - Re: [PATCH] igmp: fix ip_mc_sf

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Mon, 04 Jan 2010 14:07:03 +0100
From:	Eric Dumazet <eric.dumazet@...il.com>
To:	Flavio Leitner <fbl@...close.org>
CC:	David Miller <davem@...emloft.net>, netdev@...r.kernel.org
Subject: Re: [PATCH] igmp: fix ip_mc_sf_allow race

Le 04/01/2010 12:29, Flavio Leitner a écrit :
 
> Then, I tried using call_rcu() to avoid the problem you are saying,
> but when you stop the reproducer, sk_free() will warn printing 
> "optmem leakage.." because the rcu callback didn't run yet.
> 
> 

This is probably because your call_rcu() callback was trying to call sock_kfree_s() ?

 		rtnl_unlock();
		call_rcu(&iml->lock, callback_func)

callback_func()
{
	sock_kfree_s(sk, iml, sizeof(*iml));
}



Take a look at sock_kfree_s() definition :

void sock_kfree_s(struct sock *sk, void *mem, int size)
{
        kfree(mem);
        atomic_sub(size, &sk->sk_omem_alloc);
}


You can certainly try :

	rtnl_unlock();
	atomic_sub(sizeof(*iml), sk->sk_omem_alloc);
	call_rcu(&iml->rcu, kfree);

(immediate sk_omem_alloc handling, but deferred kfree())

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html