From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 017B3C433EF for ; Wed, 29 Sep 2021 18:10:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D995D61465 for ; Wed, 29 Sep 2021 18:10:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345785AbhI2SMa (ORCPT ); Wed, 29 Sep 2021 14:12:30 -0400 Received: from mail.skyhub.de ([5.9.137.197]:57414 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345750AbhI2SM3 (ORCPT ); Wed, 29 Sep 2021 14:12:29 -0400 Received: from zn.tnic (p200300ec2f0bd10085b5178de8b08a0e.dip0.t-ipconnect.de [IPv6:2003:ec:2f0b:d100:85b5:178d:e8b0:8a0e]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id D98361EC085D; Wed, 29 Sep 2021 20:10:46 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1632939047; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:in-reply-to:in-reply-to: references:references; bh=flm68oMHx/+MuJxWJha6OvNdd2faDkjkF+qvgbEBqoc=; b=O/lltXBB++myJjaNxsacWPa7RmyZ1XHHuJHaYtuJHVt5UGIAy88gqWCIYeyg23tQrIEBjk 830Vw1YnB6T/qIi0LETxAb5r9kUlIDKt7Yh0d8RIRS2VR41reuIqF3jIcOHV9RqeeEYuvn qONSaCpgNzYTUnsZ7LvINL0ex6wlhgM= Date: Wed, 29 Sep 2021 20:10:42 +0200 From: Borislav Petkov To: Linus Torvalds Cc: Thomas Gleixner , Linux Kernel Mailing List , the arch/x86 maintainers , Masami Hiramatsu , Adrian Hunter , Ian Rogers Subject: [PATCH] x86/insn: Use get_unaligned() instead of memcpy() Message-ID: References: <163265189226.178609.9712455554034472888.tglx@xen13> <163265189517.178609.6605494600326137493.tglx@xen13> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Borislav Petkov Use get_unaligned() instead of memcpy() to access potentially unaligned memory, which, when accessed through a pointer, leads to undefined behavior. get_unaligned() describes much better what is happening there anyway even if memcpy() does the job. No functional changes. Fixes: 5ba1071f7554 ("x86/insn, tools/x86: Fix undefined behavior due to potential unaligned accesses") Suggested-by: Linus Torvalds Signed-off-by: Borislav Petkov --- arch/x86/lib/insn.c | 5 +++-- tools/arch/x86/lib/insn.c | 5 +++-- tools/include/asm-generic/unaligned.h | 23 +++++++++++++++++++++++ 3 files changed, 29 insertions(+), 4 deletions(-) create mode 100644 tools/include/asm-generic/unaligned.h diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c index c565def611e2..55e371cc69fd 100644 --- a/arch/x86/lib/insn.c +++ b/arch/x86/lib/insn.c @@ -13,6 +13,7 @@ #endif #include /*__ignore_sync_check__ */ #include /* __ignore_sync_check__ */ +#include /* __ignore_sync_check__ */ #include #include @@ -37,10 +38,10 @@ ((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr) #define __get_next(t, insn) \ - ({ t r; memcpy(&r, insn->next_byte, sizeof(t)); insn->next_byte += sizeof(t); leXX_to_cpu(t, r); }) + ({ t r = get_unaligned((t *)(insn)->next_byte); (insn)->next_byte += sizeof(t); leXX_to_cpu(t, r); }) #define __peek_nbyte_next(t, insn, n) \ - ({ t r; memcpy(&r, (insn)->next_byte + n, sizeof(t)); leXX_to_cpu(t, r); }) + ({ t r = get_unaligned((t *)(insn)->next_byte + n); leXX_to_cpu(t, r); }) #define get_next(t, insn) \ ({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; __get_next(t, insn); }) diff --git a/tools/arch/x86/lib/insn.c b/tools/arch/x86/lib/insn.c index 797699462cd8..8fd63a067308 100644 --- a/tools/arch/x86/lib/insn.c +++ b/tools/arch/x86/lib/insn.c @@ -13,6 +13,7 @@ #endif #include "../include/asm/inat.h" /* __ignore_sync_check__ */ #include "../include/asm/insn.h" /* __ignore_sync_check__ */ +#include "../include/asm-generic/unaligned.h" /* __ignore_sync_check__ */ #include #include @@ -37,10 +38,10 @@ ((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr) #define __get_next(t, insn) \ - ({ t r; memcpy(&r, insn->next_byte, sizeof(t)); insn->next_byte += sizeof(t); leXX_to_cpu(t, r); }) + ({ t r = get_unaligned((t *)(insn)->next_byte); (insn)->next_byte += sizeof(t); leXX_to_cpu(t, r); }) #define __peek_nbyte_next(t, insn, n) \ - ({ t r; memcpy(&r, (insn)->next_byte + n, sizeof(t)); leXX_to_cpu(t, r); }) + ({ t r = get_unaligned((t *)(insn)->next_byte + n); leXX_to_cpu(t, r); }) #define get_next(t, insn) \ ({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; __get_next(t, insn); }) diff --git a/tools/include/asm-generic/unaligned.h b/tools/include/asm-generic/unaligned.h new file mode 100644 index 000000000000..47387c607035 --- /dev/null +++ b/tools/include/asm-generic/unaligned.h @@ -0,0 +1,23 @@ +/* SPDX-License-Identifier: GPL-2.0-or-later */ +/* + * Copied from the kernel sources to tools/perf/: + */ + +#ifndef __TOOLS_LINUX_ASM_GENERIC_UNALIGNED_H +#define __TOOLS_LINUX_ASM_GENERIC_UNALIGNED_H + +#define __get_unaligned_t(type, ptr) ({ \ + const struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \ + __pptr->x; \ +}) + +#define __put_unaligned_t(type, val, ptr) do { \ + struct { type x; } __packed *__pptr = (typeof(__pptr))(ptr); \ + __pptr->x = (val); \ +} while (0) + +#define get_unaligned(ptr) __get_unaligned_t(typeof(*(ptr)), (ptr)) +#define put_unaligned(val, ptr) __put_unaligned_t(typeof(*(ptr)), (val), (ptr)) + +#endif /* __TOOLS_LINUX_ASM_GENERIC_UNALIGNED_H */ + -- 2.29.2 -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette