Date:   Thu, 18 Nov 2021 15:23:36 +0100
Message-ID: <s5hee7diluf.wl-tiwai@suse.de>
From:   Takashi Iwai <tiwai@suse.de>
To:     Kees Cook <keescook@chromium.org>
Cc:     Dinh Nguyen <dinguyen@kernel.org>,
        "Ivan T . Ivanov" <iivanov@suse.de>,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux-hardening@vger.kernel.org
Subject: Re: [PATCH] ARM: socfpga: Fix crash with CONFIG_FORTIRY_SOURCE
In-Reply-To: <s5hsfvtkjoh.wl-tiwai@suse.de>
References: <20211117193244.31162-1-tiwai@suse.de>
        <202111171400.618456DCE9@keescook>
        <s5hsfvtkjoh.wl-tiwai@suse.de>
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On Thu, 18 Nov 2021 08:27:26 +0100,
Takashi Iwai wrote:
> 
> On Wed, 17 Nov 2021 23:01:50 +0100,
> Kees Cook wrote:
> > 
> > On Wed, Nov 17, 2021 at 08:32:44PM +0100, Takashi Iwai wrote:
> > > When CONFIG_FORTIFY_SOURCE is set, memcpy() checks the potential
> > > buffer overflow and panics.  The code in sofcpga bootstrapping
> > > contains the memcpy() calls are mistakenly translated as the shorter
> > > size, hence it triggers a panic as if it were overflowing.
> > > 
> > > This patch adds the __NO_FORTIFY define for avoiding the
> > > false-positive crash.
> > > 
> > > Buglink: https://bugzilla.suse.com/show_bug.cgi?id=1192473
> > > Signed-off-by: Takashi Iwai <tiwai@suse.de>
> > > ---
> > > 
> > > I took an easier path for now, as the attempt with a foced cast
> > > failed.  If there is a better way to handle, let me know, I'd happily
> > > resubmit.  Thanks!
> > > 
> > 
> > The way these have been fixed in the past is to declare these as char
> > arrays (see include/asm-generic/sections.h). I'd prefer something like
> > this (totally untested):
> (snip)
> 
> That looks better, indeed.  I'll rebuild the kernel with it and ask
> the bug reporter for testing it.

Confirmed to work.  Will resubmit the v2 patch.


thanks,

Takashi