Received: by 2002:a25:1985:0:0:0:0:0 with SMTP id 127csp4230677ybz; Tue, 28 Apr 2020 07:53:08 -0700 (PDT) X-Google-Smtp-Source: APiQypItSdz6KTbXU6yLhtGDnJlxRufUSMw5g6DnwkkNI/hi+rBoJPOAutqdPu1oSf1AaTVJ7IQY X-Received: by 2002:a17:906:2988:: with SMTP id x8mr24284046eje.16.1588085587902; Tue, 28 Apr 2020 07:53:07 -0700 (PDT) ARC-Seal: i=1; a=rsa-sha256; t=1588085587; cv=none; d=google.com; s=arc-20160816; b=grUaeNjkepllDFi/dqkUYrhO+YVRE1iAN+SASWNnqmNLoJ5k2mTOlKsgTGFroBx6lW 9fYHe5n9nrNdS5WgmB0lfQJDBNCnZEIkC0F0+mRoogBR/qzWadnTR6wdpoSkP1HoaJLe TYiBtd/ELFdSXO81Ww4ZsQw+UvtZZSh5IBq3E5elz/D6yoEzS+WV8nPcA/kBqg9hAnFS /TfRH0qll+vL0pv8IyLn/mqy4jeOj4TWtUCu2HSreIFni/LHMwtbp4HvBBbU1SJ1/SBF NKOYqJdT/NVvk7EX3+hXLSDelP0KH8l969oQz3PEso+/OYpLbh82oH/IFJZiJIVHOOKU kjQg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:content-transfer-encoding:mime-version :references:in-reply-to:message-id:date:subject:cc:to:from :dkim-signature; bh=DwiHgKCJ+vGkj52u/J14/MfUOCxa3BzivJJ8eD5IcHA=; b=jKJi87YEkB5umVZzvPrcSlpGjGvV+ezOPvE13sLr5nKAhNqi5W+g0cuWuWDUuQmIV9 KbZd1BuHOtj7DBQPUh7a3jqGvWp+VHisWXOQANGMifhU9Ts0dVoE8+mBaZKxsgIt3ITA RdZYEgzUllGugXgXN2RwtS8xW3O2FmziG2OlXQAQZSDVIq7VjwAyrnyvi4UwURK5D5Uo 9LRwWYADp6pJ2GVF9yj+6EuLra/HIBKFT9xh7A5YVABoqtm5QcmaD6n3fkVKf+GhCqNC FVh/ycThoOIxEGdQEPHFBlrKGQ4w/HkOrP5WHMKsOhe9fxRuAayo5A6ntvT7gedY8WKY NNrg== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=SbNi47LS; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id w8si1837099eju.477.2020.04.28.07.52.44; Tue, 28 Apr 2020 07:53:07 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@kernel.org header.s=default header.b=SbNi47LS; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728157AbgD1OuG (ORCPT + 99 others); Tue, 28 Apr 2020 10:50:06 -0400 Received: from mail.kernel.org ([198.145.29.99]:46484 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728129AbgD1OuA (ORCPT ); Tue, 28 Apr 2020 10:50:00 -0400 Received: from localhost.localdomain (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7770C206D6; Tue, 28 Apr 2020 14:49:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588085399; bh=KQVhaFJwaQDI1LQ4GB7LyZpVuA9l1lrKtbwaO9ObaOo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SbNi47LSVdZKZiCKx5OXieBgFz0DUjpnCJw+d8ky+EBGf/9hMTjEH5FQdSwfpa4dz dVo8xHQgEcPIUhqEjBh0wR0hxCG1DDXBQZg/IaeTxSJQM/iBVtvBqUrSyeB4Lgof7O wIjlNWqIjUTtMeeXcGO5/k0pZ+DkMhnzJRVdj1OE= From: Will Deacon To: George Spelvin Cc: catalin.marinas@arm.com, Will Deacon , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, lkml@sdf.org, Hsin-Yi Wang Subject: Re: [PATCH v2] arm64: kexec_file: Avoid temp buffer for RNG seed Date: Tue, 28 Apr 2020 15:49:39 +0100 Message-Id: <158807855142.208424.6865350866606582490.b4-ty@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200330173801.GA9199@SDF.ORG> References: <202003281643.02SGhMtr029198@sdf.org> <20200330133701.GA10633@willie-the-truck> <20200330173801.GA9199@SDF.ORG> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 30 Mar 2020 17:38:01 +0000, George Spelvin wrote: > After using get_random_bytes(), you want to wipe the buffer > afterward so the seed remains secret. > > In this case, we can eliminate the temporary buffer entirely. > fdt_setprop_placeholder() returns a pointer to the property value > buffer, allowing us to put the random data directly in there without > using a temporary buffer at all. Faster and less stack all in one. Applied to arm64 (for-next/misc), thanks! [1/1] arm64: kexec_file: Avoid temp buffer for RNG seed https://git.kernel.org/arm64/c/99ee28d99607 Cheers, -- Will https://fixes.arm64.dev https://next.arm64.dev