From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-682215-1520352170-2-3383517570642918875 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, ME_NOAUTH 0.01, 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='cz', 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=1520352167; b=m1rlVWr08hx3QEiFJFJhwSPQC+aF2gW7AnpaUK5Ros9PWBR ZTZ09dIt4TZbVr+xwZQ/fo04OEjvxj8YrkI2lhRWWRgynzJsX+t5cjUSkBTlY2ZN qd3b2ZsF58wUsQm8fhrmd+wWGv+Pc4qxx1fPIBip/PUtgGUmp3ySuSHz99kXvfHO ZKiuCYm6gqtxDx1EaMMzo5ongKD3iK2sR5OfSVnDL1OkjUxIZF7mB/oTchR5dXGK 3Wt66G0pmTODiqWzU3hoFhFwCmiRzK7/ZcZeOwRtcKFn/OMeNSsm2ft47nWkZghh K6zgdOWUBGYy0KcBxxv6+aFdKvygqZ82vGy9fdw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=subject:from:to:cc:references:message-id :date:mime-version:in-reply-to:content-type :content-transfer-encoding:sender:list-id; s=arctest; t= 1520352167; bh=rMg+gzp5o/W/Dnf/es0As+0fP7dRHX2adm0bwx5BJS8=; b=B VW4kjyXbnhWwzAQ5MgC4h/zbNP3se20TaDiaNEkQQqSEtIP/Yur1QZ/mZiHhsPF1 //R64SkopfWn669GPhQeoN4M9fe/NLMRombBH6rBxdMxkr17uNjHo9cb5N+25566 aQQJP2HdEZ4cbplkWAJHmhPMfs41k72O3ZvvA1Orp+cR3ldiSg35CsaI3Su2G1U5 oDianH4fUfIZ3+A+LYecsXcsGVpRY2uGtvD5e/qpz/GNo2tl0KjW+/Z3XDObeHXT ZuHT+8lO6sSvZm/vtLFAeYnz7humsFKwMf8BHjarc24yKtdc2sclETEyeljG9muW AdmqyJ4zIBm9eWQy51MUQ== ARC-Authentication-Results: i=1; mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=suse.cz; 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=slPqyku3; 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=suse.cz header.result=pass header_is_org_domain=yes Authentication-Results: mx2.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=suse.cz; 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=slPqyku3; 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=suse.cz header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753070AbeCFQCo (ORCPT ); Tue, 6 Mar 2018 11:02:44 -0500 Received: from mail-wm0-f68.google.com ([74.125.82.68]:34469 "EHLO mail-wm0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752055AbeCFQCn (ORCPT ); Tue, 6 Mar 2018 11:02:43 -0500 X-Google-Smtp-Source: AG47ELtYpQnQO2w2fADW5eXAO8HuzpAGcNh03MBExdIZ1mAUYfv7lwpvWjD6pURYCL6AjxsjV+dSsQ== Subject: Re: [PATCH 4.4 178/193] x86/syscall: Sanitize syscall table de-references under speculation From: Jiri Slaby To: Greg Kroah-Hartman , linux-kernel@vger.kernel.org Cc: stable@vger.kernel.org, Linus Torvalds , Dan Williams , Thomas Gleixner , linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com, Andy Lutomirski , alan@linux.intel.com, David Woodhouse , Jack Wang , Jan Beulich References: <20180223170325.997716448@linuxfoundation.org> <20180223170354.028619665@linuxfoundation.org> <0a95efad-1a3d-4aab-6d94-58dd583d275a@suse.cz> Message-ID: <10c08ff1-ba52-24a1-c915-42dd0eb175aa@suse.cz> Date: Tue, 6 Mar 2018 17:02:39 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.6.0 MIME-Version: 1.0 In-Reply-To: <0a95efad-1a3d-4aab-6d94-58dd583d275a@suse.cz> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit 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 03/06/2018, 03:21 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 Which is not completely correct either. The preceding comparison should write: cmpl $NR_syscalls, %eax jae 1f to have sbb correctly working even on the last syscall number. thanks, -- js suse labs