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=-16.4 required=3.0 tests=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,URIBL_BLOCKED, 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 D1875C43613 for ; Fri, 21 Jun 2019 01:21:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A53B72084A for ; Fri, 21 Jun 2019 01:21:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="NC6cvFMG" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726996AbfFUBVf (ORCPT ); Thu, 20 Jun 2019 21:21:35 -0400 Received: from mail-pf1-f202.google.com ([209.85.210.202]:44534 "EHLO mail-pf1-f202.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726839AbfFUBUv (ORCPT ); Thu, 20 Jun 2019 21:20:51 -0400 Received: by mail-pf1-f202.google.com with SMTP id 5so3244800pff.11 for ; Thu, 20 Jun 2019 18:20:51 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=C6hPbD+Iite9Yd/m2NEQoViniv+GetSpL6U00OfqPQs=; b=NC6cvFMGa8LejGjE8bJbN1AjDuFigoPl9T5orQwUKoq5IHOK8TozHCyvx0pPD2Rm8e bAyYl6xX/9Gy6Ipt42VzJZAyzi+X8rwrGgyiJX2wO4FJoIAAshNER1I5g7DXlyexK9si XMGS9K5vDj3tcpUbP2jAxzxgnc44GP4nj6CujSLV5K8B0mf6TsN8S+Umh0dIYpi+cKUv TeeJWfiWg32yGsZouUCqeP0hIShv+te6wXoeV8hILDOXlVOqLKbveOi4H6TW1Z22WtK8 PdG1aRyg2ehyWgENrRcZiD1V78WlJpvC7CHV81NGewkkT8mPY/5rO5kwlttQr8GOIH8v cfwQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=C6hPbD+Iite9Yd/m2NEQoViniv+GetSpL6U00OfqPQs=; b=SwfgDiUtqgodg/NVXGdH7GrQ5O2QSif++gysVHsFbWW2VsWWiF3Wr/HsOgu0De9ple BfcegiKBjuR9tS7mVurvNPlAx27zesmW2LTBA0ufP9upUkfA1JC6o67b4pB3wjpT6t6M TgcspDcn5PG1ysW70C29S4lKiTJpcEV5WVNg0tzmUC4rSo9m0vhKdP3vTRQYOcTd7NO8 lPSJgQXHSfH76H6EaqDcJLiycPauBrxUhMvWjNEcvPs+0qcODDkvCOmyj+uLKyUaGhh4 GQOZoQCSOjJwWLLWDMSM6uDZDsy7qjUKM1tbwWWU/HbhzO/UGCC5RwNSohZCLubyiBAC bYuQ== X-Gm-Message-State: APjAAAUJ6cvspzc399rV7hpBND2VgZ1mRIPop9xTc5OOB49lnR5Mad3f DcYvsOfINRNh1HLWniKn6/Gx6kWHOhn3QmbmwzhClA== X-Google-Smtp-Source: APXvYqxY8KgyzR/E7rGtXtVWwMwLdjH8s+X06tcYPkPHRkAcJ+3cLw9bjREqZyBYZWv/RvvI6zuPEKjeSTS4RGxN0sM41Q== X-Received: by 2002:a63:5a02:: with SMTP id o2mr14952617pgb.93.1561080050519; Thu, 20 Jun 2019 18:20:50 -0700 (PDT) Date: Thu, 20 Jun 2019 18:19:36 -0700 In-Reply-To: <20190621011941.186255-1-matthewgarrett@google.com> Message-Id: <20190621011941.186255-26-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190621011941.186255-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.410.gd8fdbe21b5-goog Subject: [PATCH V33 25/30] Lock down perf when in confidentiality mode From: Matthew Garrett To: jmorris@namei.org Cc: linux-security@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, David Howells , Matthew Garrett , Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Howells Disallow the use of certain perf facilities that might allow userspace to access kernel data. Signed-off-by: David Howells Signed-off-by: Matthew Garrett Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo --- include/linux/security.h | 1 + kernel/events/core.c | 5 +++++ security/lockdown/lockdown.c | 1 + 3 files changed, 7 insertions(+) diff --git a/include/linux/security.h b/include/linux/security.h index 8bf426cdd151..36a9daa13bb0 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -98,6 +98,7 @@ enum lockdown_reason { LOCKDOWN_KCORE, LOCKDOWN_KPROBES, LOCKDOWN_BPF, + LOCKDOWN_PERF, LOCKDOWN_CONFIDENTIALITY_MAX, }; diff --git a/kernel/events/core.c b/kernel/events/core.c index 72d06e302e99..ac1045caa44d 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10731,6 +10731,11 @@ SYSCALL_DEFINE5(perf_event_open, return -EINVAL; } + if ((attr.sample_type & PERF_SAMPLE_REGS_INTR) && + security_is_locked_down(LOCKDOWN_PERF)) + /* REGS_INTR can leak data, lockdown must prevent this */ + return -EPERM; + /* Only privileged users can get physical addresses */ if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR) && perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c index 0a3bbf1ba01d..14edc475d75c 100644 --- a/security/lockdown/lockdown.c +++ b/security/lockdown/lockdown.c @@ -34,6 +34,7 @@ static char *lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = { [LOCKDOWN_KCORE] = "/proc/kcore access", [LOCKDOWN_KPROBES] = "use of kprobes", [LOCKDOWN_BPF] = "use of bpf", + [LOCKDOWN_PERF] = "unsafe use of perf", [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality", }; -- 2.22.0.410.gd8fdbe21b5-goog