From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D7E3FC31E45 for ; Fri, 14 Jun 2019 03:12:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AA32A2073F for ; Fri, 14 Jun 2019 03:12:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="wDBo+IsE" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725981AbfFNDMQ (ORCPT ); Thu, 13 Jun 2019 23:12:16 -0400 Received: from mail-pg1-f195.google.com ([209.85.215.195]:45352 "EHLO mail-pg1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725819AbfFNDMQ (ORCPT ); Thu, 13 Jun 2019 23:12:16 -0400 Received: by mail-pg1-f195.google.com with SMTP id s21so654929pga.12 for ; Thu, 13 Jun 2019 20:12:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=gNlfncScxDREAT7VjTEXAFzdaeKYbTqQ4JYCBMZ7gaA=; b=wDBo+IsE5CxYBr/gG7jlwGTkzvTi/KgR2RgJSMhJe7bSxoaXzF0+TdDNJK6dLehXAQ KEE7UfEPuEEdzLtOeDJj3d79e7YtVNq/zUYfIVHlxutsUIdQWnMOok8xzhUVGO/wTU68 ulCOJAXaMZaEp6vk5Lt1C67hIvkuulYIejzeRyCLcBuX3IVSZwH8JSIlylhk7jf5ZZAp ekJFzgWJkOPfXRXpgRLg5XEs6n3l8kd4NqIboYgsZw8aMww1p5p+juY2j8+fPoHS7L27 QCdRJg5NSWYQy3xOzfV5YkvCjGSfOV9srWU2QmGPVppmd2e1TGCJfqCvS3ceOE1+BmUc vgBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=gNlfncScxDREAT7VjTEXAFzdaeKYbTqQ4JYCBMZ7gaA=; b=YsqKHugJFKF64pqYBz4Ekr4RpHUVH5do3LIEaSH44EZOP1r6N7AuLHNSOKXFDvlYJF G8f6KfgbR1qmBV6A0kfRiAEGQm4UKjnAxBf2SjmodWb597URVxjMwyle0do+Vml+hKBa RizgKW6cdl4q+9RDR+GHpbK4TJ7IhwaAWgdBANmZqtEMDZi/CJTR+oPBEA64Z2xFzSqT FbFSaHRVVAyN6w82JYt/272gvFLsQwM1HYnZLN9HmYaU7KjW2rYqJ/ifwyH4AG2M3efr levUnNnflThquLqyMxB4oETAmDahlponzxYX3LMd0X+DSt4Yc4D0RhYNNom45sXsWuH9 uuwQ== X-Gm-Message-State: APjAAAUVBKClRp3PnISZp+Owwd7Wrd4nF1U4GrhsvKTvWuKTU+j92D/Z biDx1xmGQZ//SPJ0bG1XbOf6wg== X-Google-Smtp-Source: APXvYqxXLdh+hW79HVWpzsOUs22+BCA1RGWX6SL5TD48wRXqUskcIIBZrBw2ipSX0bh2MrBWtNwIEg== X-Received: by 2002:a63:e60b:: with SMTP id g11mr13414619pgh.172.1560481935400; Thu, 13 Jun 2019 20:12:15 -0700 (PDT) Received: from localhost ([122.172.66.84]) by smtp.gmail.com with ESMTPSA id g8sm1048468pfi.8.2019.06.13.20.12.14 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 13 Jun 2019 20:12:14 -0700 (PDT) From: Viresh Kumar To: linux-arm-kernel@lists.infradead.org, Julien Thierry Cc: Viresh Kumar , stable@vger.kernel.org, Catalin Marinas , Marc Zyngier , Mark Rutland , Will Deacon , Russell King , Vincent Guittot , mark.brown@arm.com Subject: [PATCH v4.4 08/45] arm64: uaccess: Prevent speculative use of the current addr_limit Date: Fri, 14 Jun 2019 08:37:51 +0530 Message-Id: X-Mailer: git-send-email 2.21.0.rc0.269.g1a574e7a288b In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Will Deacon commit c2f0ad4fc089cff81cef6a13d04b399980ecbfcc upstream. A mispredicted conditional call to set_fs could result in the wrong addr_limit being forwarded under speculation to a subsequent access_ok check, potentially forming part of a spectre-v1 attack using uaccess routines. This patch prevents this forwarding from taking place, but putting heavy barriers in set_fs after writing the addr_limit. Reviewed-by: Mark Rutland Signed-off-by: Will Deacon Signed-off-by: Catalin Marinas Signed-off-by: Viresh Kumar --- arch/arm64/include/asm/uaccess.h | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/arm64/include/asm/uaccess.h b/arch/arm64/include/asm/uaccess.h index 75363d723262..fc11c50af558 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -62,6 +62,13 @@ extern int fixup_exception(struct pt_regs *regs); static inline void set_fs(mm_segment_t fs) { current_thread_info()->addr_limit = fs; + + /* + * Prevent a mispredicted conditional call to set_fs from forwarding + * the wrong address limit to access_ok under speculation. + */ + dsb(nsh); + isb(); } #define segment_eq(a, b) ((a) == (b)) -- 2.21.0.rc0.269.g1a574e7a288b