From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yx1-f42.google.com (mail-yx1-f42.google.com [74.125.224.42]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 47B3E334680 for ; Thu, 16 Oct 2025 17:12:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.224.42 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760634775; cv=none; b=KKmK/EbpVO6cRm1JJszbS20VRg9mO7WNrUSO106hU2cbC3oqX5EqLn6eSKvDXru6bWU76Jvuw02FwETdkqQ+IdI2g9ssqnxhKFO+h8CokGZrndr1W7QYQ9SPR4U+hhSW1WQrFpCRaTnxc3rghTgcSNHfsmhg4I4ONZvoIgHuieU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1760634775; c=relaxed/simple; bh=8A7wCpXm1JqrQZTVWt5e1TOjfU9szELdGKOs9esdIBg=; h=MIME-Version:References:In-Reply-To:From:Date:Message-ID:Subject: To:Cc:Content-Type; b=OZlcCT8zDVHyp3cicUAaow9FnUyC6ldiNolmLvdnILDcVLU0pqGra1QSXMVqHjC/MNRkkmvJHErntIpjAsmQ2ZmfKFKDQxx3eR71f3ylqPXEiX+7IGyyRqJUujA56cDcJ0B77AaGma00xvkrfb3grWSxfRfOxEXjzqa91Z7/ZcA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org; spf=pass smtp.mailfrom=linuxfoundation.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=GZWZmODQ; arc=none smtp.client-ip=74.125.224.42 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linuxfoundation.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="GZWZmODQ" Received: by mail-yx1-f42.google.com with SMTP id 956f58d0204a3-633be3be1e6so1595763d50.1 for ; Thu, 16 Oct 2025 10:12:53 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; t=1760634772; x=1761239572; darn=vger.kernel.org; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:from:to:cc:subject:date :message-id:reply-to; bh=QEY5Cy32ywjnG1KYtsZ69zGjm5flZHjdxa1tdX4atCo=; b=GZWZmODQilZplvjlDNNhWqYtFQEvQNDXf6uSqRSNskuSqejOP+eDhQ4X/gWeYG13j3 zp/3+NkqQ405DgY7jljvaP1bGjGsakqjZAIa6eXMTVtJgDVl+qc9UwJPnujNbSINZHTn zb1f5bCGYMQP9IvwIg3LxjmppJaaMCxWgl4yc= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760634772; x=1761239572; h=content-transfer-encoding:cc:to:subject:message-id:date:from :in-reply-to:references:mime-version:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=QEY5Cy32ywjnG1KYtsZ69zGjm5flZHjdxa1tdX4atCo=; b=OG2mW2AcyKUqMZgW7uHANgHbYj5loxXeYWcEjJXhSgzCW1uBVzm+U4ALtFVUxaOWoo zyrcZqd8UdADcNgIOv/SiC/d6xvutZyWU42LZCRXISzjMMP8mEI7eTewxWEkYZjON/HF Iyq2S0ZKc9mKJD/UJaB74DVje6o2olZvAcE0unejRGiy36w9r7B5CZi4jBnuqTMSiXdM /vY25OVzCN3PBYW0GB6mjss/jXNGS4TnXwSRV/4rgNsIl9j/V5iyXe8dNV0CwUk+Z8sb FBSvMw7tK5k7TxrxiLMFTYRKBlDAXGeVk72p6cxFuvJ98dkPJvNoPT0sXIasAqO3iQYL Powg== X-Gm-Message-State: AOJu0YzTXX3Kk+kPOq4Fw0+yEhbnrPkn4uXeYutr9MrkLdEWTzSj5DYp 578TEyG+P+d629Ti7t71wkxpE21kYaddIZ0dJyajJHRSJD1Wcoby3+358IjDWes/oU50vRjPiYL 8Rd0MuCNNXtkW8AR7RGV1uB8U31PIHieWhli+G+Hdfw== X-Gm-Gg: ASbGnctivlnBggV8ucBcy6P5Jjv2GDJvS9kLq9mcLoh0B1wIFjELANJKdZ1ykMdA7Vi OnFC0zeK2XV6zpsA/Id6IzNwdgIFAnCtAbmiIdc0csBmkyALEOswXp04arXKCopt2OP2SeyN6MJ w/OlpVVeuKMRD0ebTlS6EIBtM8nmMHHat1CDT3QdGSQG4xVnOFSG8vMcIsFiCQCf4W8gjISeMSu OE9Kqte+UpDr5vPaNgDGHD3/aftTMrnF+SXqRQC5/V6Cwz6cQjuG+Ne7Spl X-Google-Smtp-Source: AGHT+IHIVChKRIlE1k1ZiXM3xSKosZMb8JmwlvyNDeWwwrUbPzRan5wkOh+PiDmRNET3cvprFeHkRihy0QFAu6MUr/8= X-Received: by 2002:a05:690e:1591:10b0:629:3bfd:99aa with SMTP id 956f58d0204a3-63e08e4d99cmr88152d50.11.1760634772114; Thu, 16 Oct 2025 10:12:52 -0700 (PDT) Precedence: bulk X-Mailing-List: linux-sparse@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 References: <20251016110415.630506-1-ben.dooks@codethink.co.uk> In-Reply-To: <20251016110415.630506-1-ben.dooks@codethink.co.uk> From: Linus Torvalds Date: Thu, 16 Oct 2025 10:12:40 -0700 X-Gm-Features: AS18NWAz2bwux6Q667g3J8LAZWoJBUPF3Xlkv6jef8W4SkqfQ7kQdYQN9vsGDiY Message-ID: Subject: Re: Add printf/scanf -Wformat checking To: Ben Dooks Cc: linux-sparse@vger.kernel.org, Luc Van Oostenryck , Chris Li Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Thu, Oct 16, 2025 at 4:04=E2=80=AFAM Ben Dooks wrote: > > [re-send as I can't type sparse and messages didn't get to the list] You may need to re-send again after fixing your mailer setup, because while it made it to the list, I suspect a lot of people didn't actually get it, because it fails DKIM checks and that then tends to mean that it gets marked as spam. At least it did for me - but I check my spam folder daily, so I noticed. The reason it fails DKIM is that your codethink DKIM setup is scrogged. The DKIM message headers look like this: DKIM-Signature: v=3D1; a=3Drsa-sha256; q=3Ddns/txt; c=3Drelaxed/relaxed; d=3Dcodethink.co.uk; s=3Dimap4-20230908; so far, all good. You have DKIM, it uses relaxed/relaxed, all great. But then it continues with the list of headers that are hashed: h=3DSender:Content-Transfer-Encoding: MIME-Version:Message-Id:Date:Subject:To:From:Reply-To:Cc: All still good so far, and those are the right headers. But they are pretty much the *only* right headers, because the list of headers then goes on with Content-Type: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:References:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive= ; and that's just bogus. Having email list headers in the DKIM header hashing means that any well-behaved mailing list that adds its own subscription headers will now result in a different hash, and DKIM will fail, and anybody who reads the list with a sane MUA will not see the emails you sent. So by all means keep the "In-Reply-To" and "References" headers in the DKIM list, but get rid of all the "List-Help" etc headers, because they are actively wrong and bad. I've seen this before, and I have been told that there's some Debian DKIM help page for DKIM that lists those headers. I don't know the details, but that help page is really actively wrong and should be fixed. Typically, you should really only list the headers you really care about: things that *matter*. Things that make it clear that it was from you, and what the subject and thread was. Other headers shouldn't be hashed, exactly because there are valid reasons why those headers may then be added by intermediate mailers). Anyway, what this results in is that when I look at the headers, I see this= : ARC-Authentication-Results: i=3D1; smtp.subspace.kernel.org; dmarc=3Dpass (p=3Dreject dis=3Dnone) header.from=3Dcodethink.co.uk; spf=3Dp= ass smtp.mailfrom=3Dcodethink.com; dkim=3Dpass (2048-bit key) header.d=3Dcodethink.co.uk header.i=3D@codethink.co.uk header.b=3Dx51xpGj+; arc=3Dnone smtp.client-ip=3D188.40.203.114 Authentication-Results: smtp.subspace.kernel.org; dmarc=3Dpass (p=3Dreject dis=3Dnone) header.from=3Dcodethink.co.uk ie the list receiver is happy, because at the time the list gets the email directly from you, the DKIM hash matches, and so DMARC rules at that time say "all good". But then when the list re-sends the email out to list subscribers, they will get something like this: Authentication-Results: mx.google.com; dkim=3Dfail header.i=3D@codethink.co.uk header.s=3Dimap4-20230908 header.b=3Dx51xpGj+; because the list expander has added headers List-Id: List-Subscribe: List-Unsubscribe: (and possibly others) so now the header hash no longer matches, because you've told dkim to hash those headers. They obviously weren't there in your original email, so now the hash that codethink computed is no longer matching the headers that the list sends out. And this is a well-behaved mailing list that does what mailing lists *should* do, in adding those headers. It's really your DKIM that is actively wrong. If you remember where you got the bad list of headers from, maybe you can report this problem upstream too? Linus