From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 7C4B3390610; Tue, 11 Aug 2026 15:14:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786461279; cv=none; b=GmXGE9EviCRKBLcqip8Ga6tTgdizdxg1DGCv5WMF2Hrv9nSxQ/3Yzn7Dr9ABg3BiH8IAYk2fb0iDnfbc0QlAwxLjtHnOBhHhM4xg95h8oL00UN7QL/vgzHB0RJr4WrmPd47l/DEISFXNJdGN8cjLkQdWrrPHLR+yp8G8DP5GVxg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786461279; c=relaxed/simple; bh=Q19ghCPNMDGiSz8dEzHXQDQ1CzrmeVr5TJY+zNxx4No=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=GmaPm5VTQIGUiDg1H9SdSI9pCrQZ7wQV2eZI5rkaC6P7d+BNznEILjkYt1PFTWJiIJYHycbgDKSQBJu4Ac0kQNrIC8pCRxnqE4MhPZqaYap5p6t/8yjlJMRBzdbco1xLg67scni/BjN5IS5oAKIjg9sqAxTznOSF31qRmhAw8mg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kwVi9cZ5; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kwVi9cZ5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6C4B71F000E9; Tue, 11 Aug 2026 15:14:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786461278; bh=B5c4lkyp/O352kmRxSv99z3xaNt4JvhFYqQVngOI5Wk=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=kwVi9cZ5mJDbomvempSuT38rEX96yv1TgwsDLUDunVpi1syrOHg7zwScqRdYGd5kl n5hl2gPdjH6upwxFkyly8dJbNzmTb6fyu3Jt52bHGe6mEZy8tceQJWK8QWN5sJQLMq fZ8FVaysZQ/xKq3oCKA63Bik6teeyJ7ZtayoSlt26LNQl1CWtCLIgfqExBEtZ4XptE j1MjzOA9HFzluoW9QpTKQlus+Eu3UFz9ZJT4rlJnv855B2juyNzkmnJ6LGDsrRYYZk 1TqC/3v8nKn6nYyaSvmYLtCNqy2JokCVn3qEMdMy6G4ZkM2rKEwyS6Q9lvh8KTOazn nHU7iyeHYKUeg== Message-ID: <8bb53d9a-8870-410c-9a41-f8b536ef0780@kernel.org> Date: Tue, 11 Aug 2026 17:14:32 +0200 Precedence: bulk X-Mailing-List: linux-security-module@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/4] mm/secretmem: zeroize secret pages before kdump To: =?UTF-8?Q?Jan_Sebastian_G=C3=B6tte?= , =?UTF-8?Q?Jan_Sebastian_G=C3=B6tte?= Cc: devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, keyrings@vger.kernel.org, linux-mm@kvack.org, linux-security-module@vger.kernel.org, linux-integrity@vger.kernel.org References: <20260731162739.158320-1-linux@jaseg.de> <20260731162739.158320-4-linux@jaseg.de> <70c578dc-769f-465f-a146-4a4695f747c1@kernel.org> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 8/11/26 17:05, Jan Sebastian Götte wrote: > On 8/11/26 16:53, David Hildenbrand (Arm) wrote: >> On 7/31/26 18:27, Jan Sebastian Götte wrote: >>> Register a CRASH_ZEROIZE notifier that wipes secretmem folios. As a >>> result, when CONFIG_CRASH_ZEROIZE is set, secretmem areas will be >>> cleared before the kdump kernel is kexec'ed. >> >> Are you actually using secretmem in your use case? I heard some rumors that >> secretmem isn't used all that much in practice :) > > I'm aware nobody is really using secretmem. I decided to build this on top of > secretmem because it's an existing API that actually kind of fits the use case. > While I could have added a new API just for this (marking userspace memory as > wipe-on-crash), making it part of secretmem instead gives some additional > defense-in-depth protection for both users who only need wiping, and for users > who only want secretmem's additional protection against kernel memory read > primitives so I think everyone wins here. What I was thinking when I looked at patch #3+#4: 50% of the users you add are irrelevant in practice. Or are you saying that you are going to start using secretmem for your use case? -- Cheers, David