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 <YTG9fAQTha7ZP/kh@kroah.com>
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From:   Sandy Harris <sandyinchina@gmail.com>
Date:   Tue, 16 Nov 2021 08:47:26 +0800
Message-ID: <CACXcFmkwRi9+guXc0v_t=pP6nMidKprD1EJdGTmEsU4puyit-A@mail.gmail.com>
Subject: Re: memset() in crypto code
To:     Greg KH <gregkh@linuxfoundation.org>
Cc:     Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        linux-hardening@vger.kernel.org
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On Fri, Sep 3, 2021 at 2:15 PM Greg KH <gregkh@linuxfoundation.org> wrote:
>
> On Fri, Sep 03, 2021 at 09:13:43AM +0800, Sandy Harris wrote:
> > Doing this the crypto directory:
> > grep memset *.c | wc -l
> > I get 137 results.
> >
> > The compiler may optimise memset() away, subverting the intent of
> > these operations. We have memzero_explicit() to avoid that problem.
> >
> > Should most or all those memset() calls be replaced?
>
> The ones that are determined to actually need this, sure, but a simple
> grep like that does not actually show that.  You need to read the code
> itself to determine the need or not, please do so.

Done. Patches to follow. I ended up making about a dozen changes
in eight files. Of course, while I did read the code, I do not know it
deeply so I may have misjudged some.