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=-17.4 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,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=unavailable 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 9F5E7C7618F for ; Thu, 18 Jul 2019 19:45:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7723B208C0 for ; Thu, 18 Jul 2019 19:45:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="KjZeWxLz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404102AbfGRTp2 (ORCPT ); Thu, 18 Jul 2019 15:45:28 -0400 Received: from mail-vs1-f74.google.com ([209.85.217.74]:33851 "EHLO mail-vs1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404051AbfGRTpW (ORCPT ); Thu, 18 Jul 2019 15:45:22 -0400 Received: by mail-vs1-f74.google.com with SMTP id x22so7298984vsj.1 for ; Thu, 18 Jul 2019 12:45:21 -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=GlHyjiKYcevEFIyOZW8SL29SSZvUxPfaX8jHBCGYcts=; b=KjZeWxLzRjaEewcNpBwxH4bE4M0nnZ1BuixJyCLfzZCmjc13Tv1LVmxIlZh2L4CiZN GtxNdz5wNF+CzOZuTHsFYtDsOCj9ZY2bqHZifpLTMjBjqBq00YYNTbIn0Jew8W5q70Vl XTyheqJWhQwlcD8q9h9ZW6ohwqh5wGDGcIUK8H7cpd3liEBEVHpdtMPf+RaVR1KN+z45 1Imx51gl8srUzXKQh0pncST/cmOc7izMujQraVKmwwviPQdZaaB+gINNpZJSjPsOGdcP mb7uDRnKnZEqtmSXwP9DOU1nE59u2XmNfPTfBuGPHJ9Q34GZWiZJOKvcpNYUAZJJaqwZ ouDw== 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=GlHyjiKYcevEFIyOZW8SL29SSZvUxPfaX8jHBCGYcts=; b=JzPna3NjA6ZL7AHGsZE+nqd2YMwypOAgenVun0dmoX/4u2U6MbCO2LuXgkt1aNelTu 2bCRS1gdDM/jh3ZGj86In8sciwSdamrN02fCk9QptI3EFoAf6T5D+RifqLCHzbeWbXrb +zEuqz/K5ToP3IC7LJJdWCbQgXP06X3bKzJcAuRr89KgGYGF9fg+XG3jTX4gC4aWdtpx jZqDmu5Lv716OZThP2vLpyfEZeg9CyOhnfONDZ2pemAfFmIc3AOYFcRKBGe9gHcAL5iN RpRJ7/YjxSfXmtSDGrUskrO3QC9LSVfLueGD/SygOEvvEG05g5c8qbIN2z4C8DDrhmjJ Lcpw== X-Gm-Message-State: APjAAAW0Hm2lCYtCUoXoB7NnE2iokA4zjLdeZF8wOzjfnF7/n4HpGh3W tJ0W6thvv+QEZKJDYl/HeBel2SgGz5TLdQeL7hoa/w== X-Google-Smtp-Source: APXvYqzqfSSnMa83xZI4pbsWAteKtmq2fSntxtFajOxrJ53OslB4e9IXvjgwNQNVpEM39FEfNiu2Is+F0l5fFdtxv4bk1A== X-Received: by 2002:ab0:308c:: with SMTP id h12mr29575921ual.72.1563479120915; Thu, 18 Jul 2019 12:45:20 -0700 (PDT) Date: Thu, 18 Jul 2019 12:44:10 -0700 In-Reply-To: <20190718194415.108476-1-matthewgarrett@google.com> Message-Id: <20190718194415.108476-25-matthewgarrett@google.com> Mime-Version: 1.0 References: <20190718194415.108476-1-matthewgarrett@google.com> X-Mailer: git-send-email 2.22.0.510.g264f2c817a-goog Subject: [PATCH V36 24/29] Lock down perf when in confidentiality mode From: Matthew Garrett To: jmorris@namei.org Cc: linux-security-module@vger.kernel.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, David Howells , Matthew Garrett , Kees Cook , 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 Reviewed-by: Kees Cook Cc: Peter Zijlstra Cc: Ingo Molnar Cc: Arnaldo Carvalho de Melo --- include/linux/security.h | 1 + kernel/events/core.c | 7 +++++++ security/lockdown/lockdown.c | 1 + 3 files changed, 9 insertions(+) diff --git a/include/linux/security.h b/include/linux/security.h index 8dd1741a52cd..8ef366de70b0 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -119,6 +119,7 @@ enum lockdown_reason { LOCKDOWN_KCORE, LOCKDOWN_KPROBES, LOCKDOWN_BPF_READ, + LOCKDOWN_PERF, LOCKDOWN_CONFIDENTIALITY_MAX, }; diff --git a/kernel/events/core.c b/kernel/events/core.c index 785d708f8553..738d6f1cf5ec 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10806,6 +10806,13 @@ SYSCALL_DEFINE5(perf_event_open, perf_paranoid_kernel() && !capable(CAP_SYS_ADMIN)) return -EACCES; + err = security_locked_down(LOCKDOWN_PERF); + if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR)) + /* REGS_INTR can leak data, lockdown must prevent this */ + return err; + + err = 0; + /* * In cgroup mode, the pid argument is used to pass the fd * opened to the cgroup directory in cgroupfs. The cpu argument diff --git a/security/lockdown/lockdown.c b/security/lockdown/lockdown.c index 1b89d3e8e54d..fb437a7ef5f2 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_READ] = "use of bpf to read kernel RAM", + [LOCKDOWN_PERF] = "unsafe use of perf", [LOCKDOWN_CONFIDENTIALITY_MAX] = "confidentiality", }; -- 2.22.0.510.g264f2c817a-goog