From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-767234-1520352707-2-3300821053851554261 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='com', MailFrom='org' X-Spam-charsets: plain='UTF-8' 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=1520352706; b=tJF/yuTe4tyz+xuC+5NEs/SkdqzBMhx085sveEoU+724pMR J71OzvN+Vh5Tm1ttZ6POeh6C5mKZp+Mq9NcgIed0s+UV1yxHKCMxyENnuIjOkVAR b11ogZttJRySjiMVNo/wsPhxcCztqDvn961K4hpbm4Z20/EYuP5UOrIQhPJ5mfGu UBfQv4S/j3vL7A+xcdpLEk/pPkdmqVTwUr9W0d0K+qKgbyjv4BAVRf0w+OMg13w1 uZLbfReBNTJl2WHCZugEZ9ZBGfP2pLN9mGpYqNzBaXhFGu84zAm9VnyoWGa17lJw Ul+UlEhtklynwuoZxpp75oU+73Jej7pqftscLGA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=mime-version:in-reply-to:references:from :date:message-id:subject:to:cc:content-type:sender:list-id; s= arctest; t=1520352706; bh=jwhuBsSbRHxJ3CJ1o7dgBgi8n4/HAiWh3mxEfx 1y04g=; b=j6TmC7SbfGWHfG/TuntR9hpszrqcFQhLN/AN0wfgkAq3kGcEVuAbGX zbUVwTAjxgm/6USdReUbZ59ZOVJuHjgQ+9uDqqoCCtrJI7go2lNB++n8cGdyXuE0 h147lUllab8Y3b800ejuEkLpgO3D3GG2TkH/3p9pFVsQcrsKMjDAVsueJKjDO/6E 9WwTMucLokv20D2FdTNLedIDVzw92SjHiSJPpwVkWuAbO2KGQDEWg8ubZtnQQxIn k4AYPbfIy65qDVHHGyWtI3+MFcN7D72S5hshRxvCHnrldwTpe0FleGN94af/aARZ n0joErdszWpfFLTTasppp7wuXwbdLQog== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=profitbricks-com.20150623.gappssmtp.com header.i=@profitbricks-com.20150623.gappssmtp.com header.b=isf45b16 x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20150623; dmarc=none (p=none,has-list-id=yes,d=none) header.from=profitbricks.com; 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-category=clean score=-100 state=0; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=SSldFb7I; 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=profitbricks.com header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=pass (2048-bit rsa key sha256) header.d=profitbricks-com.20150623.gappssmtp.com header.i=@profitbricks-com.20150623.gappssmtp.com header.b=isf45b16 x-bits=2048 x-keytype=rsa x-algorithm=sha256 x-selector=20150623; dmarc=none (p=none,has-list-id=yes,d=none) header.from=profitbricks.com; 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-category=clean score=-100 state=0; x-google-dkim=pass (2048-bit rsa key) header.d=1e100.net header.i=@1e100.net header.b=SSldFb7I; 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=profitbricks.com header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753070AbeCFQLn (ORCPT ); Tue, 6 Mar 2018 11:11:43 -0500 Received: from mail-qk0-f196.google.com ([209.85.220.196]:42267 "EHLO mail-qk0-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752784AbeCFQLl (ORCPT ); Tue, 6 Mar 2018 11:11:41 -0500 X-Google-Smtp-Source: AG47ELtBmjA5fVu8utfPWVyr2gopbjPZ9a0bEMBMrETUJQN6VEReyTNeAvVWN10WcIbPr55ZpxzL6O35iVFTvR7WHO0= MIME-Version: 1.0 In-Reply-To: <0a95efad-1a3d-4aab-6d94-58dd583d275a@suse.cz> References: <20180223170325.997716448@linuxfoundation.org> <20180223170354.028619665@linuxfoundation.org> <0a95efad-1a3d-4aab-6d94-58dd583d275a@suse.cz> From: Jinpu Wang Date: Tue, 6 Mar 2018 17:11:20 +0100 Message-ID: Subject: Re: [PATCH 4.4 178/193] x86/syscall: Sanitize syscall table de-references under speculation To: Jiri Slaby Cc: Greg Kroah-Hartman , linux-kernel@vger.kernel.org, stable , Linus Torvalds , Dan Williams , Thomas Gleixner , linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com, Andy Lutomirski , alan@linux.intel.com, David Woodhouse , Jan Beulich Content-Type: text/plain; charset="UTF-8" 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: On Tue, Mar 6, 2018 at 3:21 PM, Jiri Slaby wrote: > On 02/23/2018, 07:26 PM, Greg Kroah-Hartman wrote: >> 4.4-stable review patch. If anyone has any objections, please let me know. >> >> ------------------ >> >> From: Dan Williams >> >> (cherry picked from commit 2fbd7af5af8665d18bcefae3e9700be07e22b681) >> >> The syscall table base is a user controlled function pointer in kernel >> space. Use array_index_nospec() to prevent any out of bounds speculation. >> >> While retpoline prevents speculating into a userspace directed target it >> does not stop the pointer de-reference, the concern is leaking memory >> relative to the syscall table base, by observing instruction cache >> behavior. >> >> Reported-by: Linus Torvalds >> Signed-off-by: Dan Williams >> Signed-off-by: Thomas Gleixner >> Cc: linux-arch@vger.kernel.org >> Cc: kernel-hardening@lists.openwall.com >> Cc: gregkh@linuxfoundation.org >> Cc: Andy Lutomirski >> Cc: alan@linux.intel.com >> Link: https://lkml.kernel.org/r/151727417984.33451.1216731042505722161.stgit@dwillia2-desk3.amr.corp.intel.com >> Signed-off-by: David Woodhouse >> [jwang: port to 4.4, no syscall_64] > > This is not complete IMO, the syscall is indeed there, only written in > assembly in 4.4 yet. > > So this patch looks like it is missing these two hunks (from my > SLE12-SP2 backport): > >> --- a/arch/x86/entry/entry_64.S >> +++ b/arch/x86/entry/entry_64.S >> @@ -184,6 +184,8 @@ entry_SYSCALL_64_fastpath: >> cmpl $__NR_syscall_max, %eax >> #endif >> ja 1f /* return -ENOSYS (already in pt_regs->ax) */ >> + sbb %rcx, %rcx /* array_index_mask_nospec() */ >> + and %rcx, %rax >> movq %r10, %rcx >> #ifdef CONFIG_RETPOLINE >> movq sys_call_table(, %rax, 8), %rax >> @@ -282,6 +284,8 @@ tracesys_phase2: >> cmpl $__NR_syscall_max, %eax >> #endif >> ja 1f /* return -ENOSYS (already in pt_regs->ax) */ >> + sbb %rcx, %rcx /* array_index_mask_nospec() */ >> + and %rcx, %rax >> movq %r10, %rcx /* fixup for C */ >> #ifdef CONFIG_RETPOLINE >> movq sys_call_table(, %rax, 8), %rax > > Discovered by Jan Beulich. > > thanks, > -- > js > suse labs Thanks Jiri, yes, indeed, could you send a formal patch of the fix? Thanks! Jack Wang