linux-kernel - Re: [GIT] Networking

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Message-ID: <20170710100531.GA14940@gondor.apana.org.au>
Date:   Mon, 10 Jul 2017 18:05:32 +0800
From:   Herbert Xu <herbert@...dor.apana.org.au>
To:     David Miller <davem@...emloft.net>
Cc:     sowmini.varadhan@...cle.com, torvalds@...ux-foundation.org,
        akpm@...ux-foundation.org, netdev@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [GIT] Networking

On Sun, Jul 09, 2017 at 09:40:43PM +0100, David Miller wrote:
>
> > It look like PF_ALG sets up a ->sk in alg_create() (but this
> > would get over-written in alg_accept()?) 

No it does not.  The struct socket comes from sys_accept() and
AFAICS it doesn't carry a struck sock with it.

> > Cc'ing Herbert to see if this is expected behavior (and PF_ALG
> > somehow does the right thing with the refcount for the ->sk
> > set up in alg_create) in which case I suppose we should drop the 
> > WARN_ON. 
> 
> I think we've found yet another socket leak, this time in
> AF_ALG.

Hmm, I can't see the problem in af_alg_accept.  The struct socket
comes directly from sys_accept() which creates it using sock_alloc.

So the only thing I can think of is that the memory returned by
sock_alloc is not zeroed and therefore the WARN_ON is just reading
garbage.

Cheers,
-- 
Email: Herbert Xu <herbert@...dor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt