From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AH8x226TthLcKjmU2RewT0Hgieff65daSa1sY3DBEAKL6b/ewvbJCDN+HmPoc6DzMaET3RRQeoLB ARC-Seal: i=1; a=rsa-sha256; t=1518351437; cv=none; d=google.com; s=arc-20160816; b=051pZDnLzfMV6x9phE+3SV3MigTpGrutfAGWrJywVDcQb/6U+queqiaLBxc7J0b2Dr 5T+NADiMTUf72wT1G5tV4dn7IE/JjZupMNHLjagMoOj2ujEHoyn2VFxx/2LDfR899bv3 C9ibWsW/I9J8z47trj/sDN03serXB34zTEM4+vaBAvgXi2wCNgxnZDa2N4FD9ngH8B/0 FrwG1p/B3dhAs/JI64yOxZgdv24tgAp75Ai6X6s6+OV3igZDrjWcHLqiIVQ7eEM3QsNI V/rKDGGqBbQAlWL1SAzUmaoOq3qIL+qWogEQ1W+tjDa3yOghmZFEZZATErhLh4kw1vhi VG0Q== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:sender:user-agent:in-reply-to :content-disposition:mime-version:references:message-id:subject:cc :to:from:date:arc-authentication-results; bh=pP2KrT1Dvj4CjhwririfVAfdanPWfSR8OuYSW3pMsy4=; b=tST7Aa6K+uRJFRwvdHAnRWaagj8TMorgipiSC5ytKTPWayl02q4rn1R0z6/flsQhEI OCxoHmf+3sdy9zQdpSzijFioqz1kJe43SKob5J6i1Fjfkyu3BoEq263AnIhQK/4vc3RN UE1yGTq++L2UDXYiqF1TYWk6gwvGkUcdRfg81BfRh76u7dwE1o3OwmjXQ1j1WHCePisr GefLnEejI+0GrQhITVs763o0PA51qi5n2zsN7GOibmDBVYT1PrCrXF8EYxo+f6x+IDvx B4dFOUm/ZmJhkdo7g6kDynOvbYXjdnBuW3DrhoKu2G/l1w+6/aJx9CoWwCU7zIyDgSq5 n9pg== ARC-Authentication-Results: i=1; mx.google.com; spf=pass (google.com: best guess record for domain of linux-kselftest-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kselftest-owner@vger.kernel.org Authentication-Results: mx.google.com; spf=pass (google.com: best guess record for domain of linux-kselftest-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kselftest-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753092AbeBKMRQ (ORCPT ); Sun, 11 Feb 2018 07:17:16 -0500 Received: from isilmar-4.linta.de ([136.243.71.142]:43276 "EHLO isilmar-4.linta.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752640AbeBKMRQ (ORCPT ); Sun, 11 Feb 2018 07:17:16 -0500 Date: Sun, 11 Feb 2018 13:17:14 +0100 From: Dominik Brodowski To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, x86@kernel.org, shuah@kernel.org, Andrew Lutomirski Subject: Re: [PATCH 2/5] selftests/x86: fix vDSO selftest segfault for vsyscall=none Message-ID: <20180211121714.GA11096@isilmar-4.linta.de> References: <20180211111013.16888-1-linux@dominikbrodowski.net> <20180211111013.16888-3-linux@dominikbrodowski.net> <20180211112153.f2ni5mcuut6f6zvq@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180211112153.f2ni5mcuut6f6zvq@gmail.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kselftest-owner@vger.kernel.org X-Mailing-List: linux-kselftest@vger.kernel.org X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-THRID: =?utf-8?q?1592102766376680865?= X-GMAIL-MSGID: =?utf-8?q?1592106876200876179?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: On Sun, Feb 11, 2018 at 12:21:53PM +0100, Ingo Molnar wrote: > > * Dominik Brodowski wrote: > > > + char name[128]; > > + if (sscanf(line, "%p-%p %c-%cp %*x %*x:%*x %*u %s", > > + &start, &end, &r, &x, name) != 5) > > So that's a buffer overflow waiting to happen, if a line in 'maps' gets too large, > right? ... as does tools/testing/selftests/x86/test_vsyscall.c already now, right? Will fix both up with an additional patch. But a more generic question: Is there a quick, easy but reliable test available in userspace to determine whether int $0x80 vsyscall is available on a given system, or will cause a segfault? Thanks, Dominik