From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 181BA25C818; Wed, 8 Oct 2025 06:27:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759904850; cv=none; b=e9SZgfcqfLdLt1cPVeXnm/4+0NatduZflWlWcCXgpD/4RinOD1ma0hqYo7fLpqg0zIcC61vWBTqLbVZR/oc0EjEdpE6XWV2l/kUtm6dVTP7xE+OezY5XivsGVGjAoB6Qalrf1MTnVgraZCDJDaGlPBLgeCQD7tDVt9mZy8yHPsI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1759904850; c=relaxed/simple; bh=Qs1mNKauEw169pWFmjRqxX8J2h7bFNuvRtn6dhC3lr4=; h=Message-ID:Date:MIME-Version:From:Subject:To:Cc:References: In-Reply-To:Content-Type; b=nhtbC9dtaRHEtEtFnba1tUQ5BNm7MSPgG7suy18ZRdDc23nqLLLYLzfUr5AaZCrVim2o5NfRM5YfQMv3RARKC76fFBe9fS2KVYHD8o+h1/d+HsrDBsgtnjIyu9FfTEaoUtht/F7kwBpPE6J18Vr4PQoymCtBScKu06E0+SJCil0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=azS+FmN6; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="azS+FmN6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E225BC4CEF4; Wed, 8 Oct 2025 06:27:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1759904849; bh=Qs1mNKauEw169pWFmjRqxX8J2h7bFNuvRtn6dhC3lr4=; h=Date:From:Subject:To:Cc:References:In-Reply-To:From; b=azS+FmN6dIyzD1eIVCxubWtazWLtaoDUeK3PqV5cZV7w9EyJLXmyzaceBLK3e3jcQ z5e+RtAeJ3UoEMDALYdMxfrnFVOMZZzywYqSgRXnTyXWqs4RR1i95NePCTkNSosYFu fnPCU9AcVFc7knxgFmexMs2CLks9TCmxjI2vxtPsm+niYTyf3yMMzu5Gstg+GDxsXb gTJ1ZbLsllbur8fMDeME7aKDrRKVH+kNUYzoSYgA2WlkoirPhXDtbDC4NY97x3MVCK XllIHN7zwV2O0z+haCBYfR6B01oZftRpxnRaXvxQeEKaKLYasGVFIrpWmoNwRxb9Bk RVdF4Xb0ZLqVA== Message-ID: Date: Wed, 8 Oct 2025 08:27:25 +0200 Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Hans Verkuil Subject: Re: [PATCH 0/3] module: Add compile-time check for embedded NUL characters To: Kees Cook , Luis Chamberlain Cc: Malcolm Priestley , Mauro Carvalho Chehab , =?UTF-8?Q?Uwe_Kleine-K=C3=B6nig?= , Rusty Russell , Petr Pavlu , Daniel Gomez , Sami Tolvanen , linux-kernel@vger.kernel.org, linux-media@vger.kernel.org, linux-modules@vger.kernel.org, linux-hardening@vger.kernel.org References: <20251008033844.work.801-kees@kernel.org> Content-Language: en-US, nl In-Reply-To: <20251008033844.work.801-kees@kernel.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 08/10/2025 05:59, Kees Cook wrote: > Hi, > > A long time ago we had an issue with embedded NUL bytes in MODULE_INFO > strings[1]. While this stands out pretty strongly when you look at the > code, and we can't do anything about a binary module that just plain lies, > we never actually implemented the trivial compile-time check needed to > detect it. > > Add this check (and fix 2 instances of needless trailing semicolons that > this change exposed). > > Note that these patches were produced as part of another LLM exercise. > This time I wanted to try "what happens if I ask an LLM to go read > a specific LWN article and write a patch based on a discussion?" It > pretty effortlessly chose and implemented a suggested solution, tested > the change, and fixed new build warnings in the process. > > Since this was a relatively short session, here's an overview of the > prompts involved as I guided it through a clean change and tried to see > how it would reason about static_assert vs _Static_assert. (It wanted > to use what was most common, not what was the current style -- we may > want to update the comment above the static_assert macro to suggest > using _Static_assert directly these days...) > > I want to fix a weakness in the module info strings. Read about it > here: https://lwn.net/Articles/82305/ > > Since it's only "info" that we need to check, can you reduce the checks > to just that instead of all the other stuff? > > I think the change to the comment is redundent, and that should be > in a commit log instead. Let's just keep the change to the static assert. > > Is "static_assert" the idiomatic way to use a static assert in this > code base? I've seen _Static_assert used sometimes. > > What's the difference between the two? > > Does Linux use C11 by default now? > > Then let's not use the wrapper any more. > > Do an "allmodconfig all -s" build to verify this works for all modules > in the kernel. > > > Thanks! > > -Kees > > [1] https://lwn.net/Articles/82305/ > > Kees Cook (3): > media: dvb-usb-v2: lmedm04: Fix firmware macro definitions > media: radio: si470x: Fix DRIVER_AUTHOR macro definition > module: Add compile-time check for embedded NUL characters I reviewed the two media patches. Feel free to take this series. If you prefer that I take the two media patches, then let me know but it makes more sense in this case that you take all three. Regards, Hans > > include/linux/moduleparam.h | 3 +++ > drivers/media/radio/si470x/radio-si470x-i2c.c | 2 +- > drivers/media/usb/dvb-usb-v2/lmedm04.c | 12 ++++++------ > 3 files changed, 10 insertions(+), 7 deletions(-) >