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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 AFD6FC2BA1A for ; Tue, 7 Apr 2020 01:34:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8BD092054F for ; Tue, 7 Apr 2020 01:34:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726481AbgDGBem (ORCPT ); Mon, 6 Apr 2020 21:34:42 -0400 Received: from out01.mta.xmission.com ([166.70.13.231]:43816 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726230AbgDGBem (ORCPT ); Mon, 6 Apr 2020 21:34:42 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out01.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jLd8T-0003KF-9S; Mon, 06 Apr 2020 19:34:41 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jLd8S-0002Vt-FJ; Mon, 06 Apr 2020 19:34:41 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Linus Torvalds Cc: Bernd Edlinger , Linux Kernel Mailing List , Alexey Gladkov , Oleg Nesterov , Kees Cook , Jann Horn , Christian Brauner References: <87blobnq02.fsf@x220.int.ebiederm.org> <87lfnda3w3.fsf@x220.int.ebiederm.org> <87wo6s3wxd.fsf_-_@x220.int.ebiederm.org> Date: Mon, 06 Apr 2020 20:31:52 -0500 In-Reply-To: <87wo6s3wxd.fsf_-_@x220.int.ebiederm.org> (Eric W. Biederman's message of "Mon, 06 Apr 2020 20:29:50 -0500") Message-ID: <87imic3wtz.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=1jLd8S-0002Vt-FJ;;;mid=<87imic3wtz.fsf_-_@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18oi+lq2LNPkBvf0FQ+az02C9Ie0QAYJFE= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 2/3] exec: Make unlocking exec_update_mutex explict X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org With install_exec_creds updated to follow immediately after setup_new_exec, the failure of unshare_sighand is the only code path where exec_update_mutex is held but not explicitly unlocked. Update that code path to explicitly unlock exec_update_mutex. Remove the unlocking of exec_update_mutex from free_bprm. Signed-off-by: "Eric W. Biederman" --- fs/exec.c | 6 +++--- include/linux/binfmts.h | 3 +-- 2 files changed, 4 insertions(+), 5 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index d55710a36056..28c87020da9b 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1318,7 +1318,7 @@ int flush_old_exec(struct linux_binprm * bprm) */ retval = unshare_sighand(me); if (retval) - goto out; + goto out_unlock; set_fs(USER_DS); me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | @@ -1335,6 +1335,8 @@ int flush_old_exec(struct linux_binprm * bprm) do_close_on_exec(me->files); return 0; +out_unlock: + mutex_unlock(&me->signal->exec_update_mutex); out: return retval; } @@ -1451,8 +1453,6 @@ static void free_bprm(struct linux_binprm *bprm) { free_arg_pages(bprm); if (bprm->cred) { - if (bprm->called_exec_mmap) - mutex_unlock(¤t->signal->exec_update_mutex); mutex_unlock(¤t->signal->cred_guard_mutex); abort_creds(bprm->cred); } diff --git a/include/linux/binfmts.h b/include/linux/binfmts.h index a345d9fed3d8..6f564b9ad882 100644 --- a/include/linux/binfmts.h +++ b/include/linux/binfmts.h @@ -47,8 +47,7 @@ struct linux_binprm { secureexec:1, /* * Set by flush_old_exec, when exec_mmap has been called. - * This is past the point of no return, when the - * exec_update_mutex has been taken. + * This is past the point of no return. */ called_exec_mmap:1; #ifdef __alpha__ -- 2.25.0