netdev - Re: [PATCH net] net/handshake: fix null-ptr-deref in handshake_nl_done

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Message-ID: <38F21A5C-DDFB-45C4-98BE-1690A3E5CA42@oracle.com>
Date: Thu, 31 Aug 2023 14:03:20 +0000
From: Chuck Lever III <chuck.lever@...cle.com>
To: Paolo Abeni <pabeni@...hat.com>
CC: Eric Dumazet <edumazet@...gle.com>,
        "David S . Miller"
	<davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "eric.dumazet@...il.com"
	<eric.dumazet@...il.com>,
        syzbot <syzkaller@...glegroups.com>
Subject: Re: [PATCH net] net/handshake: fix null-ptr-deref in
 handshake_nl_done_doit()



> On Aug 31, 2023, at 3:54 AM, Paolo Abeni <pabeni@...hat.com> wrote:
> 
> On Mon, 2023-08-28 at 09:13 +0000, Eric Dumazet wrote:
>> We should not call trace_handshake_cmd_done_err() if socket lookup has failed.
> 
> I think Chuck would like to have a tracepoint for all the possible
> handshake_nl_done_doit() failures, but guess that could be added later
> on net-next, possibly refactoring the arguments list (e.g. adding an
> explicit fd arg, and passing explicitly a NULL sk).

Agree. A separate trace point that requires fewer arguments
can be added later for this case. But I don't feel like the
omission here is a show stopper.


>> Also we should call trace_handshake_cmd_done_err() before releasing the file,
>> otherwise dereferencing sock->sk can return garbage.
>> 
>> This also reverts 7afc6d0a107f ("net/handshake: Fix uninitialized local variable")
> 
> I can be low on coffee, but
> 
> struct handshake_req *req = NULL;
> 
> is still there after this patch ?!?
> 
> Cheers,
> 
> Paolo
> 

--
Chuck Lever