From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Cyrus-Session-Id: sloti22d1t05-1465196-1518185167-2-8614893876875319228 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='US', 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=1518185166; b=dET4WfR3FTQVTez8dR8qHDPBpXQY4JQvS08t6vjEj7PyZTm +M0knaaNirKuY0gCtSrC//7yP5Gl8MLRSW3Y2wmcNZbQkZT0pWd/BX8pSglU9XE6 KFDN2jcINt14BJvg60QoLflnzs733CKeDmPWVKCaP1qmINedX1jVKJjI9/fq0Qyd X1nbmusfrJunUMGYo05NBdn5Q3SCC5ouL1aJI0zFymXMm7ISTvGG6gMbtQeXk1Ec 38HFG3Fb0n+JvJyrOiztCcG6owUQjAHa3qRmLWs9gi+iL01Gix3jUtsPe1mJrzZF BJURX16qbfBiCysT9eFvTN241CgkOKiybdyjjGg== 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=1518185166; bh=gZA3dbX0ns+XMEksinixFSeb+S /ySMIAUmqnKkLqXNM=; b=LCgYF/oqgVIGkrKieQ5Ni6YdUdh82+EtmaNSTMLOYQ XB6KBN9GDGEu8BoCuWxDVh7aptgox6d98xN4yFikuO0fZXgHBJDX5qrJX4NTWWpk CCfUAgUyYJR7PV5c4gfgzsS1dPqccsyxEXiC8dIXXy7HOMr9MEyfqe4a2RLCUA5s XzmALHTHZ+3Qpo6dicaF+1uh0V3P5NQNlCeUBp09EFiNXbyZlm8DU+TywC6RS0pR VBmu4/t6IpNlOsElRJ1xlSwkC3t8ZiY6yLpnxyo4jw3ujzIihOXNCcYIb7h0wnM6 wT4rGqrOLrM6qvkRj1S4xddiod9RzZo7TL5vcuox/R9g== 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 S1751145AbeBINm4 (ORCPT ); Fri, 9 Feb 2018 08:42:56 -0500 Received: from mail.linuxfoundation.org ([140.211.169.12]:50070 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753109AbeBINmy (ORCPT ); Fri, 9 Feb 2018 08:42:54 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Linus Torvalds , Dan Williams , Thomas Gleixner , linux-arch@vger.kernel.org, kernel-hardening@lists.openwall.com, alan@linux.intel.com, David Woodhouse Subject: [PATCH 4.9 58/92] x86: Implement array_index_mask_nospec Date: Fri, 9 Feb 2018 14:39:27 +0100 Message-Id: <20180209133935.416247744@linuxfoundation.org> X-Mailer: git-send-email 2.16.1 In-Reply-To: <20180209133931.211869118@linuxfoundation.org> References: <20180209133931.211869118@linuxfoundation.org> User-Agent: quilt/0.65 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: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Dan Williams (cherry picked from commit babdde2698d482b6c0de1eab4f697cf5856c5859) array_index_nospec() uses a mask to sanitize user controllable array indexes, i.e. generate a 0 mask if 'index' >= 'size', and a ~0 mask otherwise. While the default array_index_mask_nospec() handles the carry-bit from the (index - size) result in software. The x86 array_index_mask_nospec() does the same, but the carry-bit is handled in the processor CF flag without conditional instructions in the control flow. Suggested-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: alan@linux.intel.com Link: https://lkml.kernel.org/r/151727414808.33451.1873237130672785331.stgit@dwillia2-desk3.amr.corp.intel.com Signed-off-by: David Woodhouse Signed-off-by: Greg Kroah-Hartman --- arch/x86/include/asm/barrier.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) --- a/arch/x86/include/asm/barrier.h +++ b/arch/x86/include/asm/barrier.h @@ -23,6 +23,30 @@ #define wmb() asm volatile("sfence" ::: "memory") #endif +/** + * array_index_mask_nospec() - generate a mask that is ~0UL when the + * bounds check succeeds and 0 otherwise + * @index: array element index + * @size: number of elements in array + * + * Returns: + * 0 - (index < size) + */ +static inline unsigned long array_index_mask_nospec(unsigned long index, + unsigned long size) +{ + unsigned long mask; + + asm ("cmp %1,%2; sbb %0,%0;" + :"=r" (mask) + :"r"(size),"r" (index) + :"cc"); + return mask; +} + +/* Override the default implementation from linux/nospec.h. */ +#define array_index_mask_nospec array_index_mask_nospec + #ifdef CONFIG_X86_PPRO_FENCE #define dma_rmb() rmb() #else