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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 EAF9DECE587 for ; Mon, 14 Oct 2019 09:36:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C08D7214AE for ; Mon, 14 Oct 2019 09:36:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="XvAnoRVK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731011AbfJNJg0 (ORCPT ); Mon, 14 Oct 2019 05:36:26 -0400 Received: from merlin.infradead.org ([205.233.59.134]:55190 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730667AbfJNJg0 (ORCPT ); Mon, 14 Oct 2019 05:36:26 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=merlin.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=LsMYLS/Y8cXFlMO0GSn0Yr3BGu1XV5VAX95XcUxBpz0=; b=XvAnoRVKvYRsEt/t8d+FAEQPl B2q8swT9UjlU8sRDS9hAToqyHzJLXEvw6tO47ML5EE88nfG6Cs+/lglrJiXTvJsdGiwk7Gn3B+fOg d/KVk71GetGtHjFPkZmmNP9hpm3XNZPvZKHXKJtyG7MXCIxjQO+9ogr3UoyhzPcBvUkXJ/2FGwzjo MT6aDZxByHv6N7QmSF865+Q8m+FdLf45V1GFwZm+UvbwvUKCoYXYwRB7Z7buZsr8Uk/Y1Vjd9nu88 SBtwYHS6X1OCWrTuYhgDYfYKmmcGs4/l3uPYqMJ7urLlxx9FG5EHeWRdIq4jHkLNqjUvIcQ2btmcQ ytw851Dow==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1iJwlY-0005EW-2w; Mon, 14 Oct 2019 09:35:48 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 717FC300F3F; Mon, 14 Oct 2019 11:34:50 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 555A926530285; Mon, 14 Oct 2019 11:35:44 +0200 (CEST) Date: Mon, 14 Oct 2019 11:35:44 +0200 From: Peter Zijlstra To: "Joel Fernandes (Google)" Cc: linux-kernel@vger.kernel.org, rostedt@goodmis.org, primiano@google.com, rsavitski@google.com, jeffv@google.com, kernel-team@android.com, Alexei Starovoitov , Arnaldo Carvalho de Melo , bpf@vger.kernel.org, Daniel Borkmann , Ingo Molnar , James Morris , Jiri Olsa , Kees Cook , linux-security-module@vger.kernel.org, Matthew Garrett , Namhyung Kim , selinux@vger.kernel.org, Song Liu , "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" , Yonghong Song Subject: Re: [PATCH] perf_event: Add support for LSM and SELinux checks Message-ID: <20191014093544.GB2328@hirez.programming.kicks-ass.net> References: <20191011160330.199604-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191011160330.199604-1-joel@joelfernandes.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: selinux-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: selinux@vger.kernel.org On Fri, Oct 11, 2019 at 12:03:30PM -0400, Joel Fernandes (Google) wrote: > @@ -4761,6 +4762,7 @@ int perf_event_release_kernel(struct perf_event *event) > } > > no_ctx: > + security_perf_event_free(event); > put_event(event); /* Must be the 'last' reference */ > return 0; > } > @@ -10553,11 +10568,16 @@ perf_event_alloc(struct perf_event_attr *attr, int cpu, > } > } > > + err = security_perf_event_alloc(event); > + if (err) > + goto err_security; > + > /* symmetric to unaccount_event() in _free_event() */ > account_event(event); > > return event; > > +err_security: > err_addr_filters: > kfree(event->addr_filter_ranges); > There's a bunch of problems here I think: - err_security is named wrong; the naming scheme is to name the label after the last thing that succeeded / first thing that needs to be undone. - per that, you're forgetting to undo 'get_callchain_buffers()' - perf_event_release_kernel() is not a full match to perf_event_alloc(), inherited events get created by perf_event_alloc() but never pass through perf_event_release_kernel(). I'm thinking the below patch on top should ammend these issues; please verify. --- --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -4540,6 +4540,8 @@ static void _free_event(struct perf_even unaccount_event(event); + security_perf_event_free(event); + if (event->rb) { /* * Can happen when we close an event with re-directed output. @@ -4774,7 +4776,6 @@ int perf_event_release_kernel(struct per } no_ctx: - security_perf_event_free(event); put_event(event); /* Must be the 'last' reference */ return 0; } @@ -10595,14 +10596,18 @@ perf_event_alloc(struct perf_event_attr err = security_perf_event_alloc(event); if (err) - goto err_security; + goto err_callchain_buffer; /* symmetric to unaccount_event() in _free_event() */ account_event(event); return event; -err_security: +err_callchain_buffer: + if (!event->parent) { + if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) + put_callchain_buffers(); + } err_addr_filters: kfree(event->addr_filter_ranges);