From patchwork Tue Jul 14 13:27:41 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Eric W. Biederman" X-Patchwork-Id: 11662855 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 2188F1392 for ; Tue, 14 Jul 2020 13:30:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1302C224B1 for ; Tue, 14 Jul 2020 13:30:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728398AbgGNNaq (ORCPT ); Tue, 14 Jul 2020 09:30:46 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:48150 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725997AbgGNNaq (ORCPT ); Tue, 14 Jul 2020 09:30:46 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out01.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jvL0y-0007EU-Qt; Tue, 14 Jul 2020 07:30:32 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in01.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jvL0x-00052X-OR; Tue, 14 Jul 2020 07:30:32 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Cc: Linus Torvalds , Kees Cook , Andy Lutomirski , "H. Peter Anvin" , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Al Viro , Luis Chamberlain , , Tetsuo Handa , linux-security-module@vger.kernel.org, "Serge E. Hallyn" , James Morris , Kentaro Takeda , Casey Schaufler , John Johansen , Christoph Hellwig Date: Tue, 14 Jul 2020 08:27:41 -0500 Message-ID: <871rle8bw2.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 X-XM-SPF: eid=1jvL0x-00052X-OR;;;mid=<871rle8bw2.fsf@x220.int.ebiederm.org>;;;hst=in01.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19u6ArwG0PZV91H10uhj/KRxP3p9h+PTS0= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on sa06.xmission.com X-Spam-Level: * X-Spam-Status: No, score=1.3 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,T_TooManySym_01,XMNoVowels autolearn=disabled version=3.4.2 X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.4776] * 1.5 XMNoVowels Alpha-numberic number with no vowels * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa06 0; Body=1 Fuz1=1 Fuz2=1] * 0.0 T_TooManySym_01 4+ unique symbols in subject X-Spam-DCC: ; sa06 0; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: *; X-Spam-Relay-Country: X-Spam-Timing: total 653 ms - load_scoreonly_sql: 0.04 (0.0%), signal_user_changed: 11 (1.7%), b_tie_ro: 9 (1.4%), parse: 0.92 (0.1%), extract_message_metadata: 3.9 (0.6%), get_uri_detail_list: 1.91 (0.3%), tests_pri_-1000: 4.5 (0.7%), tests_pri_-950: 1.29 (0.2%), tests_pri_-900: 1.46 (0.2%), tests_pri_-90: 64 (9.8%), check_bayes: 62 (9.6%), b_tokenize: 10 (1.5%), b_tok_get_all: 10 (1.5%), b_comp_prob: 2.7 (0.4%), b_tok_touch_all: 37 (5.6%), b_finish: 0.81 (0.1%), tests_pri_0: 541 (82.8%), check_dkim_signature: 0.49 (0.1%), check_dkim_adsp: 2.5 (0.4%), poll_dns_idle: 0.72 (0.1%), tests_pri_10: 3.4 (0.5%), tests_pri_500: 14 (2.1%), rewrite_mail: 0.00 (0.0%) Subject: [PATCH 0/7] Implementing kernel_execve X-Spam-Flag: No X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This set of changes implements kernel_execve to remove the need for kernel threads to pass in pointers to in-kernel data structures to functions that take __user pointers. Which is part of the greater removal of set_fs work. This set of changes makes do_execve static and so I have updated the comments. This affects the comments in the x86 entry point code and the comments in tomoyo. I believe I have updated them correctly. If not please let me know. I have moved the calls of copy_strings before the call of security_bprm_creds_for_exec. Which might be of interest to the security folks. I can't see that it matters but I have copied the security folks just to be certain. By moving the initialization of the new stack that copy_strings does earlier it becomes possible to copy all of the parameters to exec before anything else is done which makes it possible to have one function kernel_execve that uncondtionally handles copying parameters from kernel space, and another function do_execveat_common which handles copying parameters from userspace. This work was inspired by Christoph Hellwig's similar patchset, which my earlier work to remove the file parameter to do_execveat_common conflicted with. https://lore.kernel.org/linux-fsdevel/20200627072704.2447163-1-hch@lst.de/ I figured that after causing all of that trouble for the set_fs work the least I could do is implement the change myself. The big practical change from Christoph's work is that he did not separate out the copying of parameters from the rest of the work of exec, which did not help the maintainability of the code. Please let me know if you see something wrong. This set of changes is against my exec-next branch: https://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace.git exec-next Eric W. Biederman (7): exec: Remove unnecessary spaces from binfmts.h exec: Factor out alloc_bprm exec: Move initialization of bprm->filename into alloc_bprm exec: Move bprm_mm_init into alloc_bprm exec: Factor bprm_execve out of do_execve_common exec: Factor bprm_stack_limits out of prepare_arg_pages exec: Implement kernel_execve arch/x86/entry/entry_32.S | 2 +- arch/x86/entry/entry_64.S | 2 +- arch/x86/kernel/unwind_frame.c | 2 +- fs/exec.c | 301 ++++++++++++++++++++++++++++------------- include/linux/binfmts.h | 20 ++- init/main.c | 4 +- kernel/umh.c | 6 +- security/tomoyo/common.h | 2 +- security/tomoyo/domain.c | 4 +- security/tomoyo/tomoyo.c | 4 +- 10 files changed, 224 insertions(+), 123 deletions(-) Eric