Date: Fri, 18 May 2012 14:49:39 -0700
From: Anton Vorontsov <anton.vorontsov@linaro.org>
To: Kees Cook <keescook@chromium.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Colin Cross <ccross@android.com>, Tony Luck <tony.luck@intel.com>,
        Arnd Bergmann <arnd@arndb.de>, John Stultz <john.stultz@linaro.org>,
        Shuah Khan <shuahkhan@gmail.com>, arve@android.com,
        Rebecca Schultz Zavin <rebecca@android.com>,
        Jesper Juhl <jj@chaosbits.net>, Randy Dunlap <rdunlap@xenotime.net>,
        Stephen Boyd <sboyd@codeaurora.org>, Thomas Meyer <thomas@m3y3r.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Marco Stornelli <marco.stornelli@gmail.com>,
        WANG Cong <xiyou.wangcong@gmail.com>, linux-kernel@vger.kernel.org,
        devel@driverdev.osuosl.org, linaro-kernel@lists.linaro.org,
        patches@linaro.org, kernel-team@android.com
Subject: Re: [PATCH 2/3] pstore/ram: Switch to persistent_ram routines
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On Thu, May 17, 2012 at 09:34:19AM -0700, Kees Cook wrote:
[...]
> > -       memcpy(buf, cxt->pstore.buf, size);
> > -       memset(buf + size, '\0', available - size);
> > +       hlen = ramoops_write_kmsg_hdr(prz);
> > +       if (size + hlen > prz->buffer_size)
> > +               size = prz->buffer_size - hlen;
> > +       persistent_ram_write(prz, cxt->pstore.buf, size);
> 
> This still needs to wipe out the remaining bytes in the buffer (the
> second memset above).
[...]
> > -       buf = cxt->virt_addr + (id * cxt->record_size);
> > -       memset(buf, '\0', cxt->record_size);
> > +       persistent_ram_free_old(cxt->przs[id]);
> 
> Same here -- erasing the buffer means wiping it with NULL bytes.

Well, with persistent_ram we don't need to actually erase buffers
(with persistent_ram we might even hold binary data). But yes,
we'd better reset size pointer, otherwise the unlinked buffer
will show up on the next reboot. Thanks for noticing!

-- 
Anton Vorontsov
Email: cbouatmailru@gmail.com
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