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=-8.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT 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 2F466C04AB3 for ; Mon, 13 May 2019 08:56:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 01837208C3 for ; Mon, 13 May 2019 08:56:45 +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="Z9kL3Iw0" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728389AbfEMI4n (ORCPT ); Mon, 13 May 2019 04:56:43 -0400 Received: from merlin.infradead.org ([205.233.59.134]:52644 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727634AbfEMI4n (ORCPT ); Mon, 13 May 2019 04:56:43 -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=YsWNQAn/oXqj/AAmCsiyvkrAsiJ6jruPNR4u9yvPwDQ=; b=Z9kL3Iw0vUjQQn2xL9rrd+TEG UivW7zGI7nKs6s+saOWgsrnSo+VOowZFiJ3B8AIlWQ3ZuuW6ORWQmW7q4Ae/J4efNP53Nf8V++pHO yJeV/ARJRj20SC+7fOqXNkBBEyFb9oUaeRrhohjVNG2ncC4VsetmBKoO3fYQqV0uuv2wdsO85gvuO bS5lrlhzqlYfBbTIClLxdC1PGYvxWbIafW9xORDDd6jrXXp7Vg2APxbQho5bGx3u1uRPTGqbYVeC3 UGNepzW35AtTfwF4XubSUYGbfNLqKs53Po0s64MIKmywMarc4RkHDd6gsGiINbxKcm6HJvGsbGM5A 4S15F4lxQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hQ6kx-0005ao-8Y; Mon, 13 May 2019 08:56:24 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 95CBD2029F877; Mon, 13 May 2019 10:56:20 +0200 (CEST) Date: Mon, 13 May 2019 10:56:20 +0200 From: Peter Zijlstra To: Ravi Bangoria Cc: jolsa@redhat.com, mpe@ellerman.id.au, maddy@linux.vnet.ibm.com, acme@kernel.org, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH 1/2] perf ioctl: Add check for the sample_period value Message-ID: <20190513085620.GN2650@hirez.programming.kicks-ass.net> References: <20190511024217.4013-1-ravi.bangoria@linux.ibm.com> <20190513074213.GH2623@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190513074213.GH2623@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 13, 2019 at 09:42:13AM +0200, Peter Zijlstra wrote: > On Sat, May 11, 2019 at 08:12:16AM +0530, Ravi Bangoria wrote: > > Add a check for sample_period value sent from userspace. Negative > > value does not make sense. And in powerpc arch code this could cause > > a recursive PMI leading to a hang (reported when running perf-fuzzer). > > > > Signed-off-by: Ravi Bangoria > > --- > > kernel/events/core.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > index abbd4b3b96c2..e44c90378940 100644 > > --- a/kernel/events/core.c > > +++ b/kernel/events/core.c > > @@ -5005,6 +5005,9 @@ static int perf_event_period(struct perf_event *event, u64 __user *arg) > > if (perf_event_check_period(event, value)) > > return -EINVAL; > > > > + if (!event->attr.freq && (value & (1ULL << 63))) > > + return -EINVAL; > > Well, perf_event_attr::sample_period is __u64. Would not be the site > using it as signed be the one in error? You forgot to mention commit: 0819b2e30ccb9, so I guess this just makes it consistent and is fine. 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=-8.3 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,USER_AGENT_MUTT 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 2F3F2C04AB1 for ; Mon, 13 May 2019 08:57:58 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (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 A1F5D2146F for ; Mon, 13 May 2019 08:57:57 +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="Z9kL3Iw0" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A1F5D2146F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 452ZTb5Nw6zDqHm for ; Mon, 13 May 2019 18:57:55 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (mailfrom) smtp.mailfrom=infradead.org (client-ip=2001:8b0:10b:1231::1; helo=merlin.infradead.org; envelope-from=peterz@infradead.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: lists.ozlabs.org; dkim=pass (2048-bit key; unprotected) header.d=infradead.org header.i=@infradead.org header.b="Z9kL3Iw0"; dkim-atps=neutral Received: from merlin.infradead.org (merlin.infradead.org [IPv6:2001:8b0:10b:1231::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 452ZS91WxszDqB5 for ; Mon, 13 May 2019 18:56:39 +1000 (AEST) 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=YsWNQAn/oXqj/AAmCsiyvkrAsiJ6jruPNR4u9yvPwDQ=; b=Z9kL3Iw0vUjQQn2xL9rrd+TEG UivW7zGI7nKs6s+saOWgsrnSo+VOowZFiJ3B8AIlWQ3ZuuW6ORWQmW7q4Ae/J4efNP53Nf8V++pHO yJeV/ARJRj20SC+7fOqXNkBBEyFb9oUaeRrhohjVNG2ncC4VsetmBKoO3fYQqV0uuv2wdsO85gvuO bS5lrlhzqlYfBbTIClLxdC1PGYvxWbIafW9xORDDd6jrXXp7Vg2APxbQho5bGx3u1uRPTGqbYVeC3 UGNepzW35AtTfwF4XubSUYGbfNLqKs53Po0s64MIKmywMarc4RkHDd6gsGiINbxKcm6HJvGsbGM5A 4S15F4lxQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by merlin.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1hQ6kx-0005ao-8Y; Mon, 13 May 2019 08:56:24 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 1000) id 95CBD2029F877; Mon, 13 May 2019 10:56:20 +0200 (CEST) Date: Mon, 13 May 2019 10:56:20 +0200 From: Peter Zijlstra To: Ravi Bangoria Subject: Re: [PATCH 1/2] perf ioctl: Add check for the sample_period value Message-ID: <20190513085620.GN2650@hirez.programming.kicks-ass.net> References: <20190511024217.4013-1-ravi.bangoria@linux.ibm.com> <20190513074213.GH2623@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190513074213.GH2623@hirez.programming.kicks-ass.net> User-Agent: Mutt/1.10.1 (2018-07-13) X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: maddy@linux.vnet.ibm.com, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, acme@kernel.org, jolsa@redhat.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Mon, May 13, 2019 at 09:42:13AM +0200, Peter Zijlstra wrote: > On Sat, May 11, 2019 at 08:12:16AM +0530, Ravi Bangoria wrote: > > Add a check for sample_period value sent from userspace. Negative > > value does not make sense. And in powerpc arch code this could cause > > a recursive PMI leading to a hang (reported when running perf-fuzzer). > > > > Signed-off-by: Ravi Bangoria > > --- > > kernel/events/core.c | 3 +++ > > 1 file changed, 3 insertions(+) > > > > diff --git a/kernel/events/core.c b/kernel/events/core.c > > index abbd4b3b96c2..e44c90378940 100644 > > --- a/kernel/events/core.c > > +++ b/kernel/events/core.c > > @@ -5005,6 +5005,9 @@ static int perf_event_period(struct perf_event *event, u64 __user *arg) > > if (perf_event_check_period(event, value)) > > return -EINVAL; > > > > + if (!event->attr.freq && (value & (1ULL << 63))) > > + return -EINVAL; > > Well, perf_event_attr::sample_period is __u64. Would not be the site > using it as signed be the one in error? You forgot to mention commit: 0819b2e30ccb9, so I guess this just makes it consistent and is fine.