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

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Message-ID: <2305475.IxNZ3AiDlf@tauon.chronox.de>
Date:   Thu, 07 Dec 2017 15:42:52 +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, 15:21:03 CET schrieb Atul Gupta:

Hi Atul,

> 
> memzero_explicit(key)?
> [Atul] may not be required as entire info of size keylen and AEAD_H_SIZE is
> copied onto kctx->key. Key data is received from user, while ghash is
> memset and locally generated

Sure, but wouldn't it make sense to zap all instances where key material was 
stored?

> 
> 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?


Ciao
Stephan