From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-2898263-1519909635-2-17420976134355295138 X-Sieve: CMU Sieve 3.0 X-Spam-known-sender: no X-Spam-score: 0.0 X-Spam-hits: BAYES_00 -1.9, HEADER_FROM_DIFFERENT_DOMAINS 0.249, RCVD_IN_DNSWL_HI -5, T_RP_MATCHES_RCVD -0.01, LANGUAGES en, BAYES_USED global, SA_VERSION 3.4.0 X-Spam-source: IP='209.132.180.67', Host='vger.kernel.org', Country='CN', FromHeader='org', MailFrom='org' X-Spam-charsets: X-Resolved-to: greg@kroah.com X-Delivered-to: greg@kroah.com X-Mail-from: stable-owner@vger.kernel.org ARC-Seal: i=1; a=rsa-sha256; cv=none; d=messagingengine.com; s=arctest; t=1519909634; b=AEQ6e513Brlj6YKAJAAz8GKb1Izr9DcTXADwgaTb1BBjLhz eb3pUMr0ZSxBpnpvq/QH3SwpylLGjCPD0ApN42O/JVwSNyv/FKk0/3AtdUkUDKHQ xwUCt+JLk9PP2TIGiIT/rN07VnqiIEbGvt7i4NtdNaVZ9f6Hxr7UHdDEKiJBMatN /hRF/CNCL5QqGHxmwF+CWUVF5VtcTrXXlAUGvrIIa5zpmev5R9VccpPCCdE9np93 kk7zrsdxYPAMoMbdK+fwf1npP3WNWW2ePG1bbrWYW7PwhGTSPqvtkRvKX9svEVjH mbMfavsxZythqEANO1punwDKrq1p03QUmqcd13A== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=from:to:cc:subject:date:message-id :in-reply-to:references:sender:list-id; s=arctest; t=1519909634; bh=B9j5UF0uESTYsHgGAtUITtbvy9Mt1eVCWXup4v2dg9E=; b=dLsanohHQ8dd aLLawzEwHh0zJxhGp1aIe74NACYfPcPgbG6h252mC+GQxHv9Ep5VS6CV9EJH7LVo BB8kyCXWv6/Jy7GnNJxamWzIJIEckRqUm/RdnTuJus/BsOdFsKt7wGMJs8U2vFAd 4fKEwxoi23Sm/fozvX9W4bxT2e9A0K88R71w7Q5eI51sWqdlgN8F1VDeQr8gvKyt 6C0BRJlwaoVQ0HitMxKuPJWnE5LS21JCfGG2w9ItKVcSpgFpJwiaW3buNe25woNS Nlt7KUNgYlSYwUPteM4gKwvhCipBrjoggQ0vekOFFsXFYxe4+7uPG6X8o67rl4JA MOY2KWlAcA== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=linaro.org header.i=@linaro.org header.b=L/9E5Ltp x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=google; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=linaro.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=c24NByrq; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linaro.org header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (1024-bit rsa key sha256) header.d=linaro.org header.i=@linaro.org header.b=L/9E5Ltp x-bits=1024 x-keytype=rsa x-algorithm=sha256 x-selector=google; dmarc=pass (p=none,has-list-id=yes,d=none) header.from=linaro.org; iprev=pass policy.iprev=209.132.180.67 (vger.kernel.org); spf=none smtp.mailfrom=stable-owner@vger.kernel.org smtp.helo=vger.kernel.org; x-aligned-from=fail; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=c24NByrq; x-ptr=pass x-ptr-helo=vger.kernel.org x-ptr-lookup=vger.kernel.org; x-return-mx=pass smtp.domain=vger.kernel.org smtp.result=pass smtp_org.domain=kernel.org smtp_org.result=pass smtp_is_org_domain=no header.domain=linaro.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030600AbeCAM45 (ORCPT ); Thu, 1 Mar 2018 07:56:57 -0500 Received: from mail-pl0-f67.google.com ([209.85.160.67]:37411 "EHLO mail-pl0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030576AbeCAM4z (ORCPT ); Thu, 1 Mar 2018 07:56:55 -0500 X-Google-Smtp-Source: AG47ELvCpEunRQHWeOqLoDTvu+swGgZUBdPEg3zyzzVel6A0znw3pOXx7vuihGz9xKQb/258cC5GKg== From: Alex Shi To: Marc Zyngier , Will Deacon , Ard Biesheuvel , Catalin Marinas , stable@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Cc: Alex Shi Subject: [PATCH 13/45] arm64: uaccess: Prevent speculative use of the current addr_limit Date: Thu, 1 Mar 2018 20:53:50 +0800 Message-Id: <1519908862-11425-14-git-send-email-alex.shi@linaro.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1519908862-11425-1-git-send-email-alex.shi@linaro.org> References: <1519908862-11425-1-git-send-email-alex.shi@linaro.org> Sender: stable-owner@vger.kernel.org X-Mailing-List: stable@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-Mailing-List: linux-kernel@vger.kernel.org List-ID: From: Will Deacon commit c2f0ad4fc089 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: Alex Shi --- 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 3531fec..00025c5 100644 --- a/arch/arm64/include/asm/uaccess.h +++ b/arch/arm64/include/asm/uaccess.h @@ -71,6 +71,13 @@ 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(); + + /* * Enable/disable UAO so that copy_to_user() etc can access * kernel memory with the unprivileged instructions. */ -- 2.7.4