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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 C37B3C48BD4 for ; Tue, 25 Jun 2019 15:30:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 983502080C for ; Tue, 25 Jun 2019 15:30:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="s+vhY6j7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732339AbfFYPa2 (ORCPT ); Tue, 25 Jun 2019 11:30:28 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:40386 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729683AbfFYPa2 (ORCPT ); Tue, 25 Jun 2019 11:30:28 -0400 Received: by mail-pl1-f195.google.com with SMTP id a93so9047901pla.7 for ; Tue, 25 Jun 2019 08:30:28 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=FFrIqfPVc5gl2KEfpAFI195WSUdWVmRdZsn8j+n7taA=; b=s+vhY6j7H+YWSqe48HW6tZxmlabxJ2syenwjd4RmZJBjpKHXMrBTrZig+dbii3zhhA +VGR1Jab8A4uPk88ZtuDWtnMuCH5r5HiDl8eH0yhOENu+DwXbJoiLA1Whwf4wWM+o1UR YvS3wqKvxshLiVlN2+2V9qLKrw5ZN8kn29edChmgB30MAP3HQGMSn3wpXbC1RncCxWTl WVsqOt/88pwBwr/+icoKD9E3LaSn3y/R5XSwo8+SlJGpTpdO229+GXK7VmRRW3vyLZ3h veyOuQudgCLKeUycWD3mWZypA7RlISjm9BoY51XjfRELcjIZm/EzGdPUSS5M0HiC/0n/ Rllg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=FFrIqfPVc5gl2KEfpAFI195WSUdWVmRdZsn8j+n7taA=; b=tr01R7BZGw0bxh5o55IYB2N3evRYndEJpsA8Hayy389uKuYnHQqRsJXUmtALZ9ONV8 qZnbMEmunXrqrrNxFS9/1KiMR5/gycfOrfgW01A/43G0Rw3qDhNaNVTTjBO1H1bdWOL7 0UZRjRwunbNJAzGrE0D+vdLxE26oJz+A/P1cap7SfM3k9KP44zHKytINpBJnQmRO91C4 /sPTLq1ZvHNNl+hAMX44RJ94N7hxx0jclrOjJFkN6wevhRbjSB1fDbWaMc7eM4pR8Ue+ +ECieuyEREDujxTux7Ri1c5xmvWFicEc65c4F6o7bTYvvv6MIXiHMMOT73n7E35676qC kQBg== X-Gm-Message-State: APjAAAX99OWQDli85X4FdQS9g7k9JJjZfFLZSjCvwTmHqVk5D682DU10 bziSbTbUYBrqPexaPOPDMhE= X-Google-Smtp-Source: APXvYqz/E3dr+kRNBgxIj8dEMGWgYKn8tmxU5oMsJvYVKbzi+wn8aJnJN7Ico2gACGEoNGLGqPbFpg== X-Received: by 2002:a17:902:bb90:: with SMTP id m16mr83984196pls.54.1561476627712; Tue, 25 Jun 2019 08:30:27 -0700 (PDT) Received: from tom-pc.ipads-lab.se.sjtu.edu.cn ([202.120.40.82]) by smtp.gmail.com with ESMTPSA id x23sm22502594pfo.112.2019.06.25.08.30.24 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 25 Jun 2019 08:30:26 -0700 (PDT) From: Dianzhang Chen To: tglx@linutronix.de Cc: mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, Dianzhang Chen Subject: [PATCH v2] x86/ptrace: Fix possible spectre-v1 in ptrace_get_debugreg() Date: Tue, 25 Jun 2019 23:30:17 +0800 Message-Id: <1561476617-3759-1-git-send-email-dianzhangchen0@gmail.com> X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The index to access the threads ptrace_bps is controlled by userspace via syscall: sys_ptrace(), hence, hence leading to a potential exploitation of the Spectre variant 1 vulnerability. The n can be controlled from: ptrace -> arch_ptrace -> ptrace_get_debugreg. Fix this by sanitizing n before using it to index thread->ptrace_bps. Signed-off-by: Dianzhang Chen --- arch/x86/kernel/ptrace.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index a166c96..cbac646 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -25,6 +25,7 @@ #include #include #include +#include #include #include @@ -643,9 +644,11 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n) { struct thread_struct *thread = &tsk->thread; unsigned long val = 0; + int index = n; if (n < HBP_NUM) { - struct perf_event *bp = thread->ptrace_bps[n]; + index = array_index_nospec(index, HBP_NUM); + struct perf_event *bp = thread->ptrace_bps[index]; if (bp) val = bp->hw.info.address; -- 2.7.4