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=-6.3 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 5BD98C35240 for ; Thu, 23 Jan 2020 10:23:26 +0000 (UTC) Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 329FE24673 for ; Thu, 23 Jan 2020 10:23:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="f0UMJKfm" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 329FE24673 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=intel-gfx-bounces@lists.freedesktop.org Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5E3246FBBD; Thu, 23 Jan 2020 10:23:21 +0000 (UTC) Received: from mail-lj1-x242.google.com (mail-lj1-x242.google.com [IPv6:2a00:1450:4864:20::242]) by gabe.freedesktop.org (Postfix) with ESMTPS id 6DA5B6E231 for ; Tue, 21 Jan 2020 17:56:07 +0000 (UTC) Received: by mail-lj1-x242.google.com with SMTP id u1so3757851ljk.7 for ; Tue, 21 Jan 2020 09:56:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=98bZxOBbCQ3VnMNuVxei8T8EkXL1AFFFNz8Ptr5Fwf4=; b=f0UMJKfmKZdH5ae7CC35Bo8JfJuzIWwRMR2d3DvgxxocOt4ZxltoLSDNLwnzFZ8sCh mHQ747HPLwIz8jiYkjw/ZBy7Z+2kGJIfn0vBm2e30i+bbMJpifVwiABEulHvlUjKF3e+ zmkyIyJf834Xz+CPHcMmtF5hwd//KEWq0xygi0vqFBd3IcGN7Ao8G+F+LXLzP7r3FTHU oWLSaaKu9S1cZeQ2mmM7DUSMHSd9Ajyf0ADQRJWavAuhTtXQndb3srd5FE+ES5vHQ81S 2hSAKezaBjD/oILoUk/qKVeqjfM7viogSA5lWNPJ1ygAzh6EIYbDvnDKr6JiQhFI5jr2 EyIQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=98bZxOBbCQ3VnMNuVxei8T8EkXL1AFFFNz8Ptr5Fwf4=; b=I4LsqYuYZ/0KhPwM+ITDIOM8Mwmud7y7fL5fFNvrsvzdLATQp/DXcXzR6JZ2Wjd1/p PDK4VQJjkk8IWHJdHJZwYxlVDHCqQvoO39MAOmeBXaBJQNMgBC5/FKwYo+yCHaghDBE1 uYlHSi9BvCuULoXTWWFfHaSaP9yncTYx9foVS5IyDPxYQeBuiuAv1NGwRNR0FNgdriKk yKST+/wyyRwa1PYTDmr2j8/VLVMWFQ3rKbCBdA8PCUAfZg+SOxGReq0255ICfNlrtjeW ug9DMNlP6ivPy1iBSfCmThSCaCvXkI8kHljrQoZnayyJ/rXtWTTVn6KIs8Vrx8t55dPc l6PA== X-Gm-Message-State: APjAAAWGEbaOUzK9FtRKgbjabMe4ONQXYpfnh8e5FMJC+3VUpiSizwWm czHsXV3zKHIkEutO7QdFjiKdzTMLPRoAwNGiuAo= X-Google-Smtp-Source: APXvYqzSduuvbYALVkj//Xrt9JfaU9cf6Qr6bCvfXcM6mqwY1KvupDpCfJTjcSWmOKPsyFlFi8k1zTlkXGNFH8MYpJ4= X-Received: by 2002:a05:651c:8f:: with SMTP id 15mr17366951ljq.109.1579629365512; Tue, 21 Jan 2020 09:56:05 -0800 (PST) MIME-Version: 1.0 References: <0548c832-7f4b-dc4c-8883-3f2b6d351a08@linux.intel.com> <9b77124b-675d-5ac7-3741-edec575bd425@linux.intel.com> <64cab472-806e-38c4-fb26-0ffbee485367@tycho.nsa.gov> <05297eff-8e14-ccdf-55a4-870c64516de8@linux.intel.com> In-Reply-To: <05297eff-8e14-ccdf-55a4-870c64516de8@linux.intel.com> From: Alexei Starovoitov Date: Tue, 21 Jan 2020 09:55:53 -0800 Message-ID: To: Alexey Budankov X-Mailman-Approved-At: Thu, 23 Jan 2020 10:23:15 +0000 Subject: Re: [Intel-gfx] [PATCH v5 01/10] capabilities: introduce CAP_PERFMON to kernel and user space X-BeenThere: intel-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Intel graphics driver community testing & development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Song Liu , Peter Zijlstra , "benh@kernel.crashing.org" , Will Deacon , Alexei Starovoitov , Stephane Eranian , "james.bottomley@hansenpartnership.com" , Paul Mackerras , Jiri Olsa , Andi Kleen , Michael Ellerman , Igor Lubashev , James Morris , Alexander Shishkin , Ingo Molnar , oprofile-list@lists.sf.net, Stephen Smalley , Serge Hallyn , Robert Richter , "selinux@vger.kernel.org" , "intel-gfx@lists.freedesktop.org" , Arnaldo Carvalho de Melo , Namhyung Kim , Thomas Gleixner , linux-arm-kernel , "linux-parisc@vger.kernel.org" , linux-kernel , Andy Lutomirski , "linux-perf-users@vger.kernel.org" , "linux-security-module@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" On Tue, Jan 21, 2020 at 9:31 AM Alexey Budankov wrote: > > > On 21.01.2020 17:43, Stephen Smalley wrote: > > On 1/20/20 6:23 AM, Alexey Budankov wrote: > >> > >> Introduce CAP_PERFMON capability designed to secure system performance > >> monitoring and observability operations so that CAP_PERFMON would assist > >> CAP_SYS_ADMIN capability in its governing role for perf_events, i915_perf > >> and other performance monitoring and observability subsystems. > >> > >> CAP_PERFMON intends to harden system security and integrity during system > >> performance monitoring and observability operations by decreasing attack > >> surface that is available to a CAP_SYS_ADMIN privileged process [1]. > >> Providing access to system performance monitoring and observability > >> operations under CAP_PERFMON capability singly, without the rest of > >> CAP_SYS_ADMIN credentials, excludes chances to misuse the credentials and > >> makes operation more secure. > >> > >> CAP_PERFMON intends to take over CAP_SYS_ADMIN credentials related to > >> system performance monitoring and observability operations and balance > >> amount of CAP_SYS_ADMIN credentials following the recommendations in the > >> capabilities man page [1] for CAP_SYS_ADMIN: "Note: this capability is > >> overloaded; see Notes to kernel developers, below." > >> > >> Although the software running under CAP_PERFMON can not ensure avoidance > >> of related hardware issues, the software can still mitigate these issues > >> following the official embargoed hardware issues mitigation procedure [2]. > >> The bugs in the software itself could be fixed following the standard > >> kernel development process [3] to maintain and harden security of system > >> performance monitoring and observability operations. > >> > >> [1] http://man7.org/linux/man-pages/man7/capabilities.7.html > >> [2] https://www.kernel.org/doc/html/latest/process/embargoed-hardware-issues.html > >> [3] https://www.kernel.org/doc/html/latest/admin-guide/security-bugs.html > >> > >> Signed-off-by: Alexey Budankov > >> --- > >> include/linux/capability.h | 12 ++++++++++++ > >> include/uapi/linux/capability.h | 8 +++++++- > >> security/selinux/include/classmap.h | 4 ++-- > >> 3 files changed, 21 insertions(+), 3 deletions(-) > >> > >> diff --git a/include/linux/capability.h b/include/linux/capability.h > >> index ecce0f43c73a..8784969d91e1 100644 > >> --- a/include/linux/capability.h > >> +++ b/include/linux/capability.h > >> @@ -251,6 +251,18 @@ extern bool privileged_wrt_inode_uidgid(struct user_namespace *ns, const struct > >> extern bool capable_wrt_inode_uidgid(const struct inode *inode, int cap); > >> extern bool file_ns_capable(const struct file *file, struct user_namespace *ns, int cap); > >> extern bool ptracer_capable(struct task_struct *tsk, struct user_namespace *ns); > >> +static inline bool perfmon_capable(void) > >> +{ > >> + struct user_namespace *ns = &init_user_ns; > >> + > >> + if (ns_capable_noaudit(ns, CAP_PERFMON)) > >> + return ns_capable(ns, CAP_PERFMON); > >> + > >> + if (ns_capable_noaudit(ns, CAP_SYS_ADMIN)) > >> + return ns_capable(ns, CAP_SYS_ADMIN); > >> + > >> + return false; > >> +} > > > > Why _noaudit()? Normally only used when a permission failure is non-fatal to the operation. Otherwise, we want the audit message. > > Some of ideas from v4 review. well, in the requested changes form v4 I wrote: return capable(CAP_PERFMON); instead of return false; That's what Andy suggested earlier for CAP_BPF. I think that should resolve Stephen's concern. _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx