linux-kernel - Re: [PATCH 2/8] pstore: Do not use crash buffer for decompression

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Date:   Wed, 14 Nov 2018 01:56:09 -0600
From:   Kees Cook <keescook@...omium.org>
To:     Joel Fernandes <joel@...lfernandes.org>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Anton Vorontsov <anton@...msg.org>,
        Colin Cross <ccross@...roid.com>,
        Tony Luck <tony.luck@...el.com>
Subject: Re: [PATCH 2/8] pstore: Do not use crash buffer for decompression

On Fri, Nov 2, 2018 at 1:24 PM, Joel Fernandes <joel@...lfernandes.org> wrote:
> On Thu, Nov 01, 2018 at 04:51:54PM -0700, Kees Cook wrote:
>>  static void decompress_record(struct pstore_record *record)
>>  {
>> +     int ret;
>>       int unzipped_len;
>
> nit: We could get rid of the unzipped_len variable now I think.

I didn't follow this -- it gets used quite a bit. I don't see a clean
way to remove it?

>> +     workspace = kmalloc(unzipped_len + record->ecc_notice_size,
>
> Should tihs be unzipped_len + record->ecc_notice_size + 1. The extra byte
> being for the NULL character of the ecc notice?
>
> This occurred to me when I saw the + 1 in ram.c. It could be better to just
> abstract the size as a macro.

Ooh, yes, good catch. I'll get this fixed.

Thanks for the review!

-- 
Kees Cook