linux-kernel - Re: net/dccp: dccp_create_openreq

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Message-ID: <20170301154011.GF15145@kernel.org>
Date:   Wed, 1 Mar 2017 12:40:11 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
Cc:     Dmitry Vyukov <dvyukov@...gle.com>,
        Gerrit Renker <gerrit@....abdn.ac.uk>,
        David Miller <davem@...emloft.net>, dccp@...r.kernel.org,
        netdev <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Eric Dumazet <edumazet@...gle.com>,
        Cong Wang <xiyou.wangcong@...il.com>,
        syzkaller <syzkaller@...glegroups.com>
Subject: Re: net/dccp: dccp_create_openreq_child freed held lock

Em Wed, Mar 01, 2017 at 12:35:10PM -0300, Arnaldo Carvalho de Melo escreveu:
> Em Wed, Mar 01, 2017 at 10:38:54AM +0100, Dmitry Vyukov escreveu:
> > Hello,
> > 
> > I've got the following report while running syzkaller fuzzer on
> > 86292b33d4b79ee03e2f43ea0381ef85f077c760:
> > 
> > 
> > It seems that dccp_create_openreq_child needs to unlock the sock if
> > dccp_feat_activate_values fails.
> 
> Yeah, can you please use the patch below, that mimics the error paths in
> sk_clone_new(), from where I think even the comment about it being a raw

Argh, s/sk_clone_new()/sk_clone_lock()/g

- Arnaldo

> copy came, but the bh_unlock_sock() didn't?
> 
> - Arnaldo
> 
> diff --git a/net/dccp/minisocks.c b/net/dccp/minisocks.c
> index 53eddf99e4f6..d20d948a98ed 100644
> --- a/net/dccp/minisocks.c
> +++ b/net/dccp/minisocks.c
> @@ -122,6 +122,7 @@ struct sock *dccp_create_openreq_child(const struct sock *sk,
>  			/* It is still raw copy of parent, so invalidate
>  			 * destructor and make plain sk_free() */
>  			newsk->sk_destruct = NULL;
> +			bh_unlock_sock(newsk);
>  			sk_free(newsk);
>  			return NULL;
>  		}