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=-8.9 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 979AAC072B5 for ; Fri, 24 May 2019 12:57:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5F6E820665 for ; Fri, 24 May 2019 12:57:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="iCZGiqc7" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391469AbfEXM5f (ORCPT ); Fri, 24 May 2019 08:57:35 -0400 Received: from mail-pg1-f193.google.com ([209.85.215.193]:46620 "EHLO mail-pg1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391124AbfEXM5f (ORCPT ); Fri, 24 May 2019 08:57:35 -0400 Received: by mail-pg1-f193.google.com with SMTP id o11so416778pgm.13 for ; Fri, 24 May 2019 05:57:34 -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=CD4kioQVFgkBRKMteVuyQoGT6FFB+zqtbCWCvWtVQrA=; b=iCZGiqc7A98iuHiHAe2YmyId2jJEvMj/+NWdDb7CZwhV/OLqooo0COa+F27AijWSpN Amvi9XDjTzPRQQtGkdaH2+tV2HmEZA5etc0/LBzyc2JjqR/K8RlspkdeOP2zyEcaiByv VFCxcL345JvYDa/4StowIM8D/V+Etho0NQetcrPHXboDHlppb8oIXhUI+tYFEnrfsOne eQus7q/DxX0acsfLzjTKvIavjp57/0bggMLIDrJLGkdLeY8RnBsvD1WyG1+u5gWLxJxV h1en81sp+S5U+iv1wfl08bLhXe+zvLmNCWzyeo5SY7tt9sogCIIlSRxtDrGHWk6kvLcD M8NQ== 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=CD4kioQVFgkBRKMteVuyQoGT6FFB+zqtbCWCvWtVQrA=; b=RnW8jN5kqeTF30sZNKPsF64xxUmWusYaz6ySwDFNVPK5PxchL5ItjmHcs97qt/ml5F /5Bm0fYL4FhOqDeU48hbWi4g1ueXjBfvm00omqmnqjmPBwtzbF3iloz6CrYSvCLe+mZm /bPwPKyDsq3TNuVrvFESoP8khcdWWQCuNMLkdg8gyQn0VHRRDX1BJdTtDxZchOpZkFhV pbQv/P59rsjXXk1UMwSj76m+4nqXuZDE4z6dqsxUpHnWg1av5Ns3Wt+5aU+IPgr35tCV xZ3ywFap5ziXpo82WADH6cYNbP2H3LpUnDROG4qEdYNE7qKI56EJ2KhHMjkFp6rE0j0I ZHDw== X-Gm-Message-State: APjAAAV3zAgpD5yjNDQ+68mwR5wtoQmCEqMcurSTa44R/zZJCCsdDwZV 4he+WfjaQje0kFkXip8NKcQqXTXH9w4HbQ== X-Google-Smtp-Source: APXvYqyRLpirLUto0XRsows3I8LALg4tGOIdNLiduUoq6G334B+V/enK/r4xWf8YVmq2uh9tRuTVtA== X-Received: by 2002:a17:90a:840a:: with SMTP id j10mr9302028pjn.29.1558702654560; Fri, 24 May 2019 05:57:34 -0700 (PDT) Received: from tom-pc.ipads-lab.se.sjtu.edu.cn ([202.120.40.82]) by smtp.gmail.com with ESMTPSA id p13sm4228796pfq.69.2019.05.24.05.57.30 (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Fri, 24 May 2019 05:57:34 -0700 (PDT) From: Dianzhang Chen To: oleg@redhat.com, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de Cc: hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org, Dianzhang Chen Subject: [PATCH] x86: fix possible spectre-v1 in ptrace_get_debugreg() Date: Fri, 24 May 2019 20:57:02 +0800 Message-Id: <1558702622-15143-1-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 n in ptrace_get_debugreg() is indirectly controlled by userspace via syscall: ptrace(defined in kernel/ptrace.c), 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 | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 4b8ee05..3f8f158 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -644,7 +645,8 @@ static unsigned long ptrace_get_debugreg(struct task_struct *tsk, int n) unsigned long val = 0; if (n < HBP_NUM) { - struct perf_event *bp = thread->ptrace_bps[n]; + struct perf_event *bp = + thread->ptrace_bps[array_index_nospec(n, HBP_NUM)]; if (bp) val = bp->hw.info.address; -- 2.7.4