Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752051AbaFEQVY (ORCPT ); Thu, 5 Jun 2014 12:21:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:1616 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751640AbaFEQVX (ORCPT ); Thu, 5 Jun 2014 12:21:23 -0400 Date: Thu, 5 Jun 2014 12:20:45 -0400 From: Dave Jones To: "Michael Kerrisk (man-pages)" , Linux Kernel , linux-mm@kvack.org, Linus Torvalds , zohar@linux.vnet.ibm.com Subject: Re: ima_mmap_file returning 0 to userspace as mmap result. Message-ID: <20140605162045.GA25474@redhat.com> Mail-Followup-To: Dave Jones , "Michael Kerrisk (man-pages)" , Linux Kernel , linux-mm@kvack.org, Linus Torvalds , zohar@linux.vnet.ibm.com References: <20140604233122.GA19838@redhat.com> <538FF4C4.5090300@gmail.com> <20140605155658.GA22673@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140605155658.GA22673@redhat.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jun 05, 2014 at 11:56:58AM -0400, Dave Jones wrote: > On Thu, Jun 05, 2014 at 06:40:36AM +0200, Michael Kerrisk (man-pages) wrote: > > On 06/05/2014 01:31 AM, Dave Jones wrote: > > > I just noticed that trinity was freaking out in places when mmap was > > > returning zero. This surprised me, because I had the mmap_min_addr > > > sysctl set to 64k, so it wasn't a MAP_FIXED mapping that did it. > > > > > > There's no mention of this return value in the man page, so I dug > > > into the kernel code, and it appears that we do.. > > > > > > sys_mmap > > > vm_mmap_pgoff > > > security_mmap_file > > > ima_file_mmap <- returns 0 if not PROT_EXEC > > > > > > and then the 0 gets propagated up as a retval all the way to userspace. > > I just realised that this affects even kernels with CONFIG_IMA unset, > because there we just do 'return 0' unconditionally. > > Also, it appears that kernels with CONFIG_SECURITY unset will also > return a zero for the same reason. Hang on, I was misreading that whole security_mmap_file ret handling code. There's something else at work here. I'll dig and get a reproducer. Dave -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/