netdev - Re: [crypto 6/8] chtls: TCB and Key program

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Message-ID: <2747471.DjaIqLtZ2I@tauon.chronox.de>
Date:   Thu, 07 Dec 2017 16:27:39 +0100
From:   Stephan Mueller <smueller@...onox.de>
To:     Atul Gupta <atul.gupta@...lsio.com>
Cc:     "herbert@...dor.apana.org.au" <herbert@...dor.apana.org.au>,
        "linux-crypto@...r.kernel.org" <linux-crypto@...r.kernel.org>,
        "netdev@...r.kernel.org" <netdev@...r.kernel.org>,
        "davem@...emloft.net" <davem@...emloft.net>,
        "davejwatson@...com" <davejwatson@...com>,
        Ganesh GR <ganeshgr@...lsio.com>,
        Harsh Jain <Harsh@...lsio.com>
Subject: Re: [crypto 6/8] chtls: TCB and Key program

Am Donnerstag, 7. Dezember 2017, 16:08:04 CET schrieb Atul Gupta:

Hi Atul,

> > As far as I see, the key is part of the skb (via kctx). This skb is
> > released after being processed. The release calls kfree_skb which does
> > not zeroize the key. Wouldn't it make sense to clear the memory of the
> > key when the skb is released? [Atul] we should perhaps memset the info
> > received from user so that driver has no info on key once its written on
> > chip memory. memset(gcm_ctx->key, 0, keylen);
> 
> Are you saying that the skb (via kctx) above does not obtain a copy of the
> key? If not, what is done in chtls_key_info? It does have a key copy, I was
> not sure how key info is accessed once skb is released.

All I am saying is that this key copy should be zapped when the memory is 
released. Thus, if the skb has a copy of the key, at least at the time of 
free() of the skb, a memset() of the key memory should be done (or before).
> 
> 
> Ciao
> Stephan
> 
> Thanks
> Atul



Ciao
Stephan