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 X-Spam-Level: X-Spam-Status: No, score=-20.4 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9C40CC433E7 for ; Thu, 15 Oct 2020 06:22:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 43CDC22249 for ; Thu, 15 Oct 2020 06:22:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="bvdjG2rQ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728656AbgJOGWB (ORCPT ); Thu, 15 Oct 2020 02:22:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38136 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725208AbgJOGV6 (ORCPT ); Thu, 15 Oct 2020 02:21:58 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7A229C061755 for ; Wed, 14 Oct 2020 23:21:56 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id m62so1915055ybb.6 for ; Wed, 14 Oct 2020 23:21:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=C80j7Nw7LdZVv12jD8G4UBrzvB65iIyHmBDpLMfgVHg=; b=bvdjG2rQGHmMvr1DZqKC/RqeSBgJsM4YcQtisq+e/149HyeCkdRsgTBmRiQPOZ+flU 4rjxozmYVmI7FP1hKEqiP6QF3KnC7rANwP1A6MjfnqRTAFGenQFYz01XoNsgDrNsfRu3 TRBuESkoTOJmXSkrMFe+TUF9ouG3aJg171p2zGcs2UdK5t0n1TvoG/SsyTIEMadHQ7Va 6f0rVbjBAD6jVINB0JHwIlXzlCSPZa3MUdi5THBqMINYQFp6bnOXXrYD8MHHItuMFGea zDvfjxgLXNKUxdcosI8ebxaGQcUhYm+dBWcu2mTE5zbWTmKuOZH9l2ir6RjyyRATGwvt 8ghg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=C80j7Nw7LdZVv12jD8G4UBrzvB65iIyHmBDpLMfgVHg=; b=Q8wdUqVcOnLiYVbPLM6MmnxpbHHaNEFULkKULPW9Syq8dKzYayG7cIMlGpoQHXPj43 GsEq6g3k7ciIfgWMdfF0Y6bri7Bzn4qCLkaHt4ro1Gu2ykfyz0OBNOvosyBwLzQpAXby 0IlktB+eKFV21cn8WPW35u5AIoAEdQxK54NQqSyv2jplNXxasRSsxShaTa05E1zxNhzZ ra0ShZWez8QNvllrEqFP18IZUIlsbwL+IYGv3uuRQt4uqEWcItw1JpmGtTeDnITXK0pG ct04BEsjiUHsTp0yC+a/P9zToACpE+6v47zivByWpxy9FpgFeTw7oX9mdudWLJ804XSz m/EQ== X-Gm-Message-State: AOAM530lA/iQ7q3b4+s/VvYj8B5mtt090lWlgc2T4XiR2clEPihGvI+T eWBHBLCfP/KeRD53ANEzV5fU3Jj8rZO9 X-Google-Smtp-Source: ABdhPJwRtI+sk5qFLEqcVagNij/+WCcI3F/UAqcAHx7xojDczOt86a6MCvQjP0wuKlFheas9VlRBvYhy4Ddr Sender: "irogers via sendgmr" X-Received: from irogers.svl.corp.google.com ([2620:15c:2cd:2:f693:9fff:fef4:4583]) (user=irogers job=sendgmr) by 2002:a25:b316:: with SMTP id l22mr3282909ybj.395.1602742915638; Wed, 14 Oct 2020 23:21:55 -0700 (PDT) Date: Wed, 14 Oct 2020 23:21:48 -0700 In-Reply-To: <20201015062148.1437894-1-irogers@google.com> Message-Id: <20201015062148.1437894-2-irogers@google.com> Mime-Version: 1.0 References: <20201015062148.1437894-1-irogers@google.com> X-Mailer: git-send-email 2.28.0.1011.ga647a8990f-goog Subject: [PATCH 2/2] tools/x86: Fix some potential undefined behavior From: Ian Rogers To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , "Peter Zijlstra (Intel)" , Masami Hiramatsu , Josh Poimboeuf , linux-kernel@vger.kernel.org, Adrian Hunter , Arnaldo Carvalho de Melo Cc: Numfor Mbiziwo-Tiapo , Ian Rogers Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Numfor Mbiziwo-Tiapo If insn_init is given a NULL kaddr and 0 buflen then validate_next will perform arithmetic on NULL, add a guard to avoid this. Don't perform unaligned loads in __get_next and __peek_nbyte_next as these are forms of undefined behavior. These problems were identified using the undefined behavior sanitizer (ubsan) with perf test. Part of this patch was previously posted here: https://lore.kernel.org/lkml/20190724184512.162887-4-nums@google.com/ Signed-off-by: Ian Rogers Signed-off-by: Numfor Mbiziwo-Tiapo --- tools/arch/x86/lib/insn.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/tools/arch/x86/lib/insn.c b/tools/arch/x86/lib/insn.c index 0151dfc6da61..e8874a8cac2c 100644 --- a/tools/arch/x86/lib/insn.c +++ b/tools/arch/x86/lib/insn.c @@ -17,13 +17,13 @@ /* Verify next sizeof(t) bytes can be on the same instruction */ #define validate_next(t, insn, n) \ - ((insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr) + ((insn)->end_kaddr != 0 && (insn)->next_byte + sizeof(t) + n <= (insn)->end_kaddr) #define __get_next(t, insn) \ - ({ t r = *(t*)insn->next_byte; insn->next_byte += sizeof(t); r; }) + ({ t r; memcpy(&r, insn->next_byte, sizeof(t)); insn->next_byte += sizeof(t); r; }) #define __peek_nbyte_next(t, insn, n) \ - ({ t r = *(t*)((insn)->next_byte + n); r; }) + ({ t r; memcpy(&r, (insn)->next_byte + n, sizeof(t)); r; }) #define get_next(t, insn) \ ({ if (unlikely(!validate_next(t, insn, 0))) goto err_out; __get_next(t, insn); }) -- 2.28.0.1011.ga647a8990f-goog