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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0EA0FC4332F for ; Tue, 1 Mar 2022 12:36:40 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 8AB038D0002; Tue, 1 Mar 2022 07:36:40 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 85A7C8D0001; Tue, 1 Mar 2022 07:36:40 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 76FCB8D0002; Tue, 1 Mar 2022 07:36:40 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0212.hostedemail.com [216.40.44.212]) by kanga.kvack.org (Postfix) with ESMTP id 642978D0001 for ; Tue, 1 Mar 2022 07:36:40 -0500 (EST) Received: from smtpin23.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 1EC2B181CAC54 for ; Tue, 1 Mar 2022 12:36:40 +0000 (UTC) X-FDA: 79195766160.23.EFBD16E Received: from outpost1.zedat.fu-berlin.de (outpost1.zedat.fu-berlin.de [130.133.4.66]) by imf10.hostedemail.com (Postfix) with ESMTP id 5E0DFC000C for ; Tue, 1 Mar 2022 12:36:39 +0000 (UTC) Received: from inpost2.zedat.fu-berlin.de ([130.133.4.69]) by outpost.zedat.fu-berlin.de (Exim 4.94) with esmtps (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (envelope-from ) id 1nP1jk-003IcG-9v; Tue, 01 Mar 2022 13:36:16 +0100 Received: from suse-laptop.physik.fu-berlin.de ([160.45.32.140]) by inpost2.zedat.fu-berlin.de (Exim 4.94) with esmtpsa (TLS1.2) tls TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 (envelope-from ) id 1nP1jk-001HI7-3q; Tue, 01 Mar 2022 13:36:16 +0100 Message-ID: <49182d0d-708b-4029-da5f-bc18603440a6@physik.fu-berlin.de> Date: Tue, 1 Mar 2022 13:36:15 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.6.1 Subject: Re: [PATCH 5.16 v2] binfmt_elf: Avoid total_mapping_size for ET_EXEC Content-Language: en-US To: Kees Cook , matoro Cc: Alexander Viro , Eric Biederman , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, stable@vger.kernel.org, =?UTF-8?Q?Magnus_Gro=c3=9f?= , Thorsten Leemhuis , Anthony Yznaga , Andrew Morton , regressions@lists.linux.dev, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-hardening@vger.kernel.org References: <20220228205518.1265798-1-keescook@chromium.org> From: John Paul Adrian Glaubitz In-Reply-To: <20220228205518.1265798-1-keescook@chromium.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Original-Sender: glaubitz@physik.fu-berlin.de X-Originating-IP: 160.45.32.140 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: 5E0DFC000C X-Rspam-User: Authentication-Results: imf10.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf10.hostedemail.com: domain of glaubitz@zedat.fu-berlin.de designates 130.133.4.66 as permitted sender) smtp.mailfrom=glaubitz@zedat.fu-berlin.de X-Stat-Signature: 4p1t6nnntkoqt95b6xsrjtxtsitf564s X-HE-Tag: 1646138199-492085 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: Hello! On 2/28/22 21:55, Kees Cook wrote: > Partially revert commit 5f501d555653 ("binfmt_elf: reintroduce using > MAP_FIXED_NOREPLACE"). > > At least ia64 has ET_EXEC PT_LOAD segments that are not virtual-address > contiguous (but _are_ file-offset contiguous). This would result in > giant mapping attempts to cover the entire span, including the virtual > address range hole. Disable total_mapping_size for ET_EXEC, which > reduces the MAP_FIXED_NOREPLACE coverage to only the first PT_LOAD: > > $ readelf -lW /usr/bin/gcc > ... > Program Headers: > Type Offset VirtAddr PhysAddr FileSiz MemSiz ... > ... > LOAD 0x000000 0x4000000000000000 0x4000000000000000 0x00b5a0 0x00b5a0 ... > LOAD 0x00b5a0 0x600000000000b5a0 0x600000000000b5a0 0x0005ac 0x000710 ... > ... > ^^^^^^^^ ^^^^^^^^^^^^^^^^^^ ^^^^^^^^ ^^^^^^^^ > > File offset range : 0x000000-0x00bb4c > 0x00bb4c bytes > > Virtual address range : 0x4000000000000000-0x600000000000bcb0 > 0x200000000000bcb0 bytes > > Ironically, this is the reverse of the problem that originally caused > problems with ET_EXEC and MAP_FIXED_NOREPLACE: overlaps. This problem is > with holes. Future work could restore full coverage if load_elf_binary() > were to perform mappings in a separate phase from the loading (where > it could resolve both overlaps and holes). > > Cc: Alexander Viro > Cc: Eric Biederman > Cc: linux-fsdevel@vger.kernel.org > Cc: linux-mm@kvack.org > Reported-by: matoro > Reported-by: John Paul Adrian Glaubitz > Fixes: 5f501d555653 ("binfmt_elf: reintroduce using MAP_FIXED_NOREPLACE") > Link: https://lore.kernel.org/r/a3edd529-c42d-3b09-135c-7e98a15b150f@leemhuis.info > Cc: stable@vger.kernel.org > Signed-off-by: Kees Cook > --- > Here's the v5.16 backport. > --- > fs/binfmt_elf.c | 25 ++++++++++++++++++------- > 1 file changed, 18 insertions(+), 7 deletions(-) > > diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c > index f8c7f26f1fbb..911a9e7044f4 100644 > --- a/fs/binfmt_elf.c > +++ b/fs/binfmt_elf.c > @@ -1135,14 +1135,25 @@ static int load_elf_binary(struct linux_binprm *bprm) > * is then page aligned. > */ > load_bias = ELF_PAGESTART(load_bias - vaddr); > - } > > - /* > - * Calculate the entire size of the ELF mapping (total_size). > - * (Note that load_addr_set is set to true later once the > - * initial mapping is performed.) > - */ > - if (!load_addr_set) { > + /* > + * Calculate the entire size of the ELF mapping > + * (total_size), used for the initial mapping, > + * due to first_pt_load which is set to false later > + * once the initial mapping is performed. > + * > + * Note that this is only sensible when the LOAD > + * segments are contiguous (or overlapping). If > + * used for LOADs that are far apart, this would > + * cause the holes between LOADs to be mapped, > + * running the risk of having the mapping fail, > + * as it would be larger than the ELF file itself. > + * > + * As a result, only ET_DYN does this, since > + * some ET_EXEC (e.g. ia64) may have virtual > + * memory holes between LOADs. > + * > + */ > total_size = total_mapping_size(elf_phdata, > elf_ex->e_phnum); > if (!total_size) { I can confirm that this patch fixes the issue for me. Tested-By: John Paul Adrian Glaubitz Thanks, Adrian -- .''`. John Paul Adrian Glaubitz : :' : Debian Developer - glaubitz@debian.org `. `' Freie Universitaet Berlin - glaubitz@physik.fu-berlin.de `- GPG: 62FF 8A75 84E0 2956 9546 0006 7426 3B37 F5B5 F913