From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1521561-1519218023-5-12007181324088555739 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 0.001, 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='org', 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=1519218022; b=mEq1HbNmXopean9JZ9fejeGPsmKL7iWZSl7FZAoOn57ilOU ihYWIU5qOYr3tm1m8dwK6Woz/iYSjx4G7AQVSyd0Opkkt/1ZspHSSXWKU9GDdUEu wnzPqABk8je+i1BOGmHXeW6en05mcJ/ZdfXKYc1GYqKTc3YIOQp6EtPln3JIF+ys NaRUPxLvE4+AwVN+WGiZiCIuuXXPlQx3ukvp5mPYPwu2YKJgFir+UDMIxG13gRuK zJiNZdro7Uwz6CjR984ow/Khf74x4Bw5ZLXr0GPbFp3RiIKxXrE5br9mtu5gv1SM ivW8na4GaXpUa+8OoXGCsagoxgmZeED+zTr5Whg== 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:mime-version:content-type:sender :list-id; s=arctest; t=1519218022; bh=fHi3RYwevtREPBwXG2a66o+/yK RMFsPPnj5YS+4Dvf4=; b=cO7LRgmwi9BuYazLeJf+Uf6UpdVeb/YMjYqjLwh+uS +DSo63tvD/p+VrVTklsWS++hokyruZWWPBF/A+lfRh6CC4wxCL6nwV/s5/HyKUG8 QsTl3ehcYTG1B4gU+CK+q1HVEETESG4grbkevSoQeB0m3noRDRmsFd48ZJnvIE/R jBvKPCTEvcLEO2kMhmFUthew42Ec5rUlI6zBqR9C6j7/r/cSS8csZQAVv7wZX27K 6v4o14juas6qVTgi3Ojk6qioCP53RWzJFhQCWBTdiaTc+sRFOAp9DFj5PKchJPXN 5NIrXtA91erQqVDvo6+xKt2ZmVmwoZ2UJ/QzR/KhL8ZQ== ARC-Authentication-Results: i=1; mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.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-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=linuxfoundation.org header.result=pass header_is_org_domain=yes Authentication-Results: mx3.messagingengine.com; arc=none (no signatures found); dkim=none (no signatures found); dmarc=none (p=none,has-list-id=yes,d=none) header.from=linuxfoundation.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-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=linuxfoundation.org header.result=pass header_is_org_domain=yes Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935283AbeBUNAO (ORCPT ); Wed, 21 Feb 2018 08:00:14 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:36898 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935281AbeBUNAN (ORCPT ); Wed, 21 Feb 2018 08:00:13 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Dan Williams , Andy Lutomirski , Borislav Petkov , Brian Gerst , Denys Vlasenko , "H. Peter Anvin" , Josh Poimboeuf , Linus Torvalds , Peter Zijlstra , Thomas Gleixner , Ingo Molnar Subject: [PATCH 4.14 057/167] x86/entry/64: Clear registers for exceptions/interrupts, to reduce speculation attack surface Date: Wed, 21 Feb 2018 13:47:48 +0100 Message-Id: <20180221124527.660437341@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180221124524.639039577@linuxfoundation.org> References: <20180221124524.639039577@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 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: 4.14-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Williams commit 3ac6d8c787b835b997eb23e43e09aa0895ef7d58 upstream. Clear the 'extra' registers on entering the 64-bit kernel for exceptions and interrupts. The common registers are not cleared since they are likely clobbered well before they can be exploited in a speculative execution attack. Originally-From: Andi Kleen Signed-off-by: Dan Williams Cc: Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/151787989146.7847.15749181712358213254.stgit@dwillia2-desk3.amr.corp.intel.com [ Made small improvements to the changelog and the code comments. ] Signed-off-by: Ingo Molnar Signed-off-by: Greg Kroah-Hartman --- arch/x86/entry/calling.h | 19 +++++++++++++++++++ arch/x86/entry/entry_64.S | 6 +++++- 2 files changed, 24 insertions(+), 1 deletion(-) --- a/arch/x86/entry/calling.h +++ b/arch/x86/entry/calling.h @@ -147,6 +147,25 @@ For 32-bit we have the following convent UNWIND_HINT_REGS offset=\offset .endm + /* + * Sanitize registers of values that a speculation attack + * might otherwise want to exploit. The lower registers are + * likely clobbered well before they could be put to use in + * a speculative execution gadget: + */ + .macro CLEAR_REGS_NOSPEC + xorl %ebp, %ebp + xorl %ebx, %ebx + xorq %r8, %r8 + xorq %r9, %r9 + xorq %r10, %r10 + xorq %r11, %r11 + xorq %r12, %r12 + xorq %r13, %r13 + xorq %r14, %r14 + xorq %r15, %r15 + .endm + .macro POP_EXTRA_REGS popq %r15 popq %r14 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -571,6 +571,7 @@ END(irq_entries_start) ALLOC_PT_GPREGS_ON_STACK SAVE_C_REGS SAVE_EXTRA_REGS + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER testb $3, CS(%rsp) @@ -1127,6 +1128,7 @@ ENTRY(xen_failsafe_callback) ALLOC_PT_GPREGS_ON_STACK SAVE_C_REGS SAVE_EXTRA_REGS + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER jmp error_exit END(xen_failsafe_callback) @@ -1172,6 +1174,7 @@ ENTRY(paranoid_entry) cld SAVE_C_REGS 8 SAVE_EXTRA_REGS 8 + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER 8 movl $1, %ebx movl $MSR_GS_BASE, %ecx @@ -1224,8 +1227,8 @@ ENTRY(error_entry) cld SAVE_C_REGS 8 SAVE_EXTRA_REGS 8 + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER 8 - xorl %ebx, %ebx testb $3, CS+8(%rsp) jz .Lerror_kernelspace @@ -1422,6 +1425,7 @@ ENTRY(nmi) pushq %r14 /* pt_regs->r14 */ pushq %r15 /* pt_regs->r15 */ UNWIND_HINT_REGS + CLEAR_REGS_NOSPEC ENCODE_FRAME_POINTER /*