Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753095AbaFFB40 (ORCPT ); Thu, 5 Jun 2014 21:56:26 -0400 Received: from mx1.redhat.com ([209.132.183.28]:3641 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753046AbaFFB4X (ORCPT ); Thu, 5 Jun 2014 21:56:23 -0400 Date: Thu, 5 Jun 2014 21:56:10 -0400 From: Dave Jones To: Mimi Zohar Cc: "Michael Kerrisk (man-pages)" , Linux Kernel , linux-mm@kvack.org, Linus Torvalds Subject: Re: ima_mmap_file returning 0 to userspace as mmap result. Message-ID: <20140606015610.GA23041@redhat.com> Mail-Followup-To: Dave Jones , Mimi Zohar , "Michael Kerrisk (man-pages)" , Linux Kernel , linux-mm@kvack.org, Linus Torvalds References: <20140604233122.GA19838@redhat.com> <538FF4C4.5090300@gmail.com> <20140605155658.GA22673@redhat.com> <20140605162045.GA25474@redhat.com> <1402019369.5458.55.camel@dhcp-9-2-203-236.watson.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1402019369.5458.55.camel@dhcp-9-2-203-236.watson.ibm.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 09:49:29PM -0400, Mimi Zohar wrote: > > > > > 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. > > According to security.h, it should return 0 if permission is granted. > If IMA is not enabled, it should also return 0. What exactly is the > problem? Still digging. I managed to get this to reproduce constantly last night, but no luck today. From re-reading the code though, I think IMA/lsm isn't the problem. 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/