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 X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 88F17C433FE for ; Tue, 14 Jul 2020 13:33:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6DEF0224B1 for ; Tue, 14 Jul 2020 13:33:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728404AbgGNNd4 (ORCPT ); Tue, 14 Jul 2020 09:33:56 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:52472 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728049AbgGNNdz (ORCPT ); Tue, 14 Jul 2020 09:33:55 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out02.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jvL4D-0002gA-MW; Tue, 14 Jul 2020 07:33:53 -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 1jvL4C-0005bi-PE; Tue, 14 Jul 2020 07:33:53 -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 References: <871rle8bw2.fsf@x220.int.ebiederm.org> Date: Tue, 14 Jul 2020 08:31:03 -0500 In-Reply-To: <871rle8bw2.fsf@x220.int.ebiederm.org> (Eric W. Biederman's message of "Tue, 14 Jul 2020 08:27:41 -0500") Message-ID: <87365u6x60.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1jvL4C-0005bi-PE;;;mid=<87365u6x60.fsf@x220.int.ebiederm.org>;;;hst=in01.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+tYbnh3Q62SSMVnifjKF7zDyhQnXaMvYo= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 6/7] exec: Factor bprm_stack_limits out of prepare_arg_pages 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-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In preparation for implementiong kernel_execve (which will take kernel pointers not userspace pointers) factor out bprm_stack_limits out of prepare_arg_pages. This separates the counting which depends upon the getting data from userspace from the calculations of the stack limits which is usable in kernel_execve. The remove prepare_args_pages and compute bprm->argc and bprm->envc directly in do_execveat_common, before bprm_stack_limits is called. Signed-off-by: "Eric W. Biederman" --- fs/exec.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index 50508892fa71..f8135dc149b3 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -448,19 +448,10 @@ static int count(struct user_arg_ptr argv, int max) return i; } -static int prepare_arg_pages(struct linux_binprm *bprm, - struct user_arg_ptr argv, struct user_arg_ptr envp) +static int bprm_stack_limits(struct linux_binprm *bprm) { unsigned long limit, ptr_size; - bprm->argc = count(argv, MAX_ARG_STRINGS); - if (bprm->argc < 0) - return bprm->argc; - - bprm->envc = count(envp, MAX_ARG_STRINGS); - if (bprm->envc < 0) - return bprm->envc; - /* * Limit to 1/4 of the max stack size or 3/4 of _STK_LIM * (whichever is smaller) for the argv+env strings. @@ -1964,7 +1955,17 @@ static int do_execveat_common(int fd, struct filename *filename, goto out_ret; } - retval = prepare_arg_pages(bprm, argv, envp); + retval = count(argv, MAX_ARG_STRINGS); + if (retval < 0) + goto out_free; + bprm->argc = retval; + + retval = count(envp, MAX_ARG_STRINGS); + if (retval < 0) + goto out_free; + bprm->envc = retval; + + retval = bprm_stack_limits(bprm); if (retval < 0) goto out_free; -- 2.25.0