Date:   Thu, 30 Dec 2021 23:36:00 +0100
From:   Borislav Petkov <bp@alien8.de>
To:     Alexander Lobakin <alexandr.lobakin@intel.com>
Cc:     linux-hardening@vger.kernel.org, x86@kernel.org,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Kristen Carlson Accardi <kristen@linux.intel.com>,
        Kees Cook <keescook@chromium.org>,
        Miklos Szeredi <miklos@szeredi.hu>,
        Ard Biesheuvel <ardb@kernel.org>,
        Tony Luck <tony.luck@intel.com>,
        Bruce Schlobohm <bruce.schlobohm@intel.com>,
        Jessica Yu <jeyu@kernel.org>,
        kernel test robot <lkp@intel.com>,
        Miroslav Benes <mbenes@suse.cz>,
        Evgenii Shatokhin <eshatokhin@virtuozzo.com>,
        Jonathan Corbet <corbet@lwn.net>,
        Masahiro Yamada <masahiroy@kernel.org>,
        Michal Marek <michal.lkml@markovi.net>,
        Nick Desaulniers <ndesaulniers@google.com>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        "David S. Miller" <davem@davemloft.net>,
        Thomas Gleixner <tglx@linutronix.de>,
        Will Deacon <will@kernel.org>, Ingo Molnar <mingo@redhat.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Arnd Bergmann <arnd@arndb.de>,
        Josh Poimboeuf <jpoimboe@redhat.com>,
        Nathan Chancellor <nathan@kernel.org>,
        Masami Hiramatsu <mhiramat@kernel.org>,
        Marios Pomonis <pomonis@google.com>,
        Sami Tolvanen <samitolvanen@google.com>,
        "H.J. Lu" <hjl.tools@gmail.com>, Nicolas Pitre <nico@fluxnic.net>,
        linux-kernel@vger.kernel.org, linux-kbuild@vger.kernel.org,
        linux-arch@vger.kernel.org, live-patching@vger.kernel.org,
        llvm@lists.linux.dev
Subject: Re: [PATCH v9 03/15] kallsyms: Hide layout
Message-ID: <Yc40UKmylVh38vl5@zn.tnic>
References: <20211223002209.1092165-1-alexandr.lobakin@intel.com>
 <20211223002209.1092165-4-alexandr.lobakin@intel.com>
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On Thu, Dec 23, 2021 at 01:21:57AM +0100, Alexander Lobakin wrote:
> Subject: Re: [PATCH v9 03/15] kallsyms: Hide layout

That title is kinda laconic...

> From: Kristen Carlson Accardi <kristen@linux.intel.com>
> 
> This patch makes /proc/kallsyms display in a random order, rather

Avoid having "This patch" or "This commit" in the commit message. It is
tautologically useless.

Also, do

$ git grep 'This patch' Documentation/process

for more details.

> than sorted by address in order to hide the newly randomized address
> layout.

Sorted by address?

My /proc/kallsyms says

$ awk '{ print $1 }' /proc/kallsyms | uniq -c
 119086 0000000000000000

so all the addresses are 0. Aha, and when I list them as root, only then
I see non-null addresses.

So why do we that patch at all?

> alobakin:
> Don't depend FG-KASLR and always do that for unpriviledged accesses

Unknown word [unpriviledged] in commit message, suggestions:
        ['unprivileged', 'underprivileged', 'privileged']

> as suggested by several folks.
> Also, introduce and use a shuffle_array() macro which shuffles an
> array using Fisher-Yates.

Fisher-Yates what?

/me goes and looks at the wikipedia article.

Aha, a Fisher-Yates shuffle algoithm.

Don't be afraid to explain more in your commit messages and make them
more reader-friendly.

> We'll make use of it several more times
> later on.

Not important for this commit.

...

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette