From patchwork Tue Mar 14 10:13:43 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Evgeniy Baskov X-Patchwork-Id: 663802 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DA998C7618B for ; Tue, 14 Mar 2023 10:20:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229832AbjCNKUW (ORCPT ); Tue, 14 Mar 2023 06:20:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40048 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230035AbjCNKTp (ORCPT ); Tue, 14 Mar 2023 06:19:45 -0400 Received: from mail.ispras.ru (mail.ispras.ru [83.149.199.84]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D03747B98A; Tue, 14 Mar 2023 03:19:11 -0700 (PDT) Received: from localhost.localdomain (unknown [83.149.199.65]) by mail.ispras.ru (Postfix) with ESMTPSA id 09D0C4076B51; Tue, 14 Mar 2023 10:18:04 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 mail.ispras.ru 09D0C4076B51 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ispras.ru; s=default; t=1678789084; bh=TGo4XV8+4rYhPXDaghQExWmkbcLCrUD/7A+lIMbYivo=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=DinlFVoZPtOfiUrfZLz2HeYSH7RAVDDFhltsS7dtCieoqHQpcphDbfmqFesJNJgVw 8ycZ7pWdCvXpHhrWXRLbfAmXx67RPiTByKTod9FpOFjD2eenBKyGUdBjhKr2xTiGX7 528XoSo853o76fvBIgzLR8VDp6Nd6A7swa/y8yGA= From: Evgeniy Baskov To: Ard Biesheuvel Cc: Evgeniy Baskov , Borislav Petkov , Andy Lutomirski , Dave Hansen , Ingo Molnar , Peter Zijlstra , Thomas Gleixner , Alexey Khoroshilov , Peter Jones , Gerd Hoffmann , "Limonciello, Mario" , joeyli , lvc-project@linuxtesting.org, x86@kernel.org, linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org Subject: [PATCH v5 16/27] x86/boot: Reduce lower limit of physical KASLR Date: Tue, 14 Mar 2023 13:13:43 +0300 Message-Id: <5a05045877c25c9ed08287e3ed829332de0ac667.1678785672.git.baskov@ispras.ru> X-Mailer: git-send-email 2.39.2 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-efi@vger.kernel.org Set lower limit of physical KASLR to 64M. Previously is was set to 512M when kernel is loaded higher than that. That prevented physical KASLR from being performed on x86_32, where upper limit is also set to 512M. The limit is pretty arbitrary, and the most important is to set it above the ISA hole, i.e. higher than 16M. It was not that important before, but now kernel is not getting relocated to the lower address when booting via EFI, exposing the KASLR failures. Tested-by: Mario Limonciello Signed-off-by: Evgeniy Baskov --- arch/x86/boot/compressed/kaslr.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/boot/compressed/kaslr.c b/arch/x86/boot/compressed/kaslr.c index 69966481b82d..806df3912396 100644 --- a/arch/x86/boot/compressed/kaslr.c +++ b/arch/x86/boot/compressed/kaslr.c @@ -850,10 +850,10 @@ void choose_random_location(unsigned long input, /* * Low end of the randomization range should be the - * smaller of 512M or the initial kernel image + * smaller of 64M or the initial kernel image * location: */ - min_addr = min(*output, 512UL << 20); + min_addr = min(*output, 64UL << 20); /* Make sure minimum is aligned. */ min_addr = ALIGN(min_addr, CONFIG_PHYSICAL_ALIGN);