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 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 8E57AC28CBC for ; Wed, 6 May 2020 13:00:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D92E206DB for ; Wed, 6 May 2020 13:00:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728706AbgEFNA1 (ORCPT ); Wed, 6 May 2020 09:00:27 -0400 Received: from out03.mta.xmission.com ([166.70.13.233]:39120 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727964AbgEFNA1 (ORCPT ); Wed, 6 May 2020 09:00:27 -0400 Received: from in02.mta.xmission.com ([166.70.13.52]) by out03.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jWJey-0007Bg-TN; Wed, 06 May 2020 07:00:24 -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 1jWJey-00061w-1F; Wed, 06 May 2020 07:00:24 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Greg Ungerer Cc: linux-kernel@vger.kernel.org, Linus Torvalds , Oleg Nesterov , Jann Horn , Kees Cook , Rob Landley , Bernd Edlinger , linux-fsdevel@vger.kernel.org, Al Viro , Alexey Dobriyan , Andrew Morton References: <87h7wujhmz.fsf@x220.int.ebiederm.org> <87bln2jhki.fsf@x220.int.ebiederm.org> Date: Wed, 06 May 2020 07:56:59 -0500 In-Reply-To: (Greg Ungerer's message of "Wed, 6 May 2020 22:42:42 +1000") Message-ID: <87v9l9dxwk.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=1jWJey-00061w-1F;;;mid=<87v9l9dxwk.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX19W5a9a8zm+g2O6M8Y98Fe+NXQMQUxKUZo= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: Re: [PATCH 1/7] binfmt: Move install_exec_creds after setup_new_exec to match binfmt_elf 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 Greg Ungerer writes: > One small nit: Good point. > On 6/5/20 5:41 am, Eric W. Biederman wrote: >> In 2016 Linus moved install_exec_creds immediately after >> setup_new_exec, in binfmt_elf as a cleanup and as part of closing a >> potential information leak. >> >> Perform the same cleanup for the other binary formats. >> >> Different binary formats doing the same things the same way makes exec >> easier to reason about and easier to maintain. >> >> The binfmt_flagt bits were tested by Greg Ungerer > ^^^^^ > flat > > Regards > Greg > > >> Ref: 9f834ec18def ("binfmt_elf: switch to new creds when switching to new mm") >> Signed-off-by: "Eric W. Biederman" >> --- >> arch/x86/ia32/ia32_aout.c | 3 +-- >> fs/binfmt_aout.c | 2 +- >> fs/binfmt_elf_fdpic.c | 2 +- >> fs/binfmt_flat.c | 3 +-- >> 4 files changed, 4 insertions(+), 6 deletions(-) >> >> diff --git a/arch/x86/ia32/ia32_aout.c b/arch/x86/ia32/ia32_aout.c >> index 9bb71abd66bd..37b36a8ce5fa 100644 >> --- a/arch/x86/ia32/ia32_aout.c >> +++ b/arch/x86/ia32/ia32_aout.c >> @@ -140,6 +140,7 @@ static int load_aout_binary(struct linux_binprm *bprm) >> set_personality_ia32(false); >> setup_new_exec(bprm); >> + install_exec_creds(bprm); >> regs->cs = __USER32_CS; >> regs->r8 = regs->r9 = regs->r10 = regs->r11 = regs->r12 = >> @@ -156,8 +157,6 @@ static int load_aout_binary(struct linux_binprm *bprm) >> if (retval < 0) >> return retval; >> - install_exec_creds(bprm); >> - >> if (N_MAGIC(ex) == OMAGIC) { >> unsigned long text_addr, map_size; >> diff --git a/fs/binfmt_aout.c b/fs/binfmt_aout.c >> index 8e8346a81723..ace587b66904 100644 >> --- a/fs/binfmt_aout.c >> +++ b/fs/binfmt_aout.c >> @@ -162,6 +162,7 @@ static int load_aout_binary(struct linux_binprm * bprm) >> set_personality(PER_LINUX); >> #endif >> setup_new_exec(bprm); >> + install_exec_creds(bprm); >> current->mm->end_code = ex.a_text + >> (current->mm->start_code = N_TXTADDR(ex)); >> @@ -174,7 +175,6 @@ static int load_aout_binary(struct linux_binprm * bprm) >> if (retval < 0) >> return retval; >> - install_exec_creds(bprm); >> if (N_MAGIC(ex) == OMAGIC) { >> unsigned long text_addr, map_size; >> diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c >> index 240f66663543..6c94c6d53d97 100644 >> --- a/fs/binfmt_elf_fdpic.c >> +++ b/fs/binfmt_elf_fdpic.c >> @@ -353,6 +353,7 @@ static int load_elf_fdpic_binary(struct linux_binprm *bprm) >> current->personality |= READ_IMPLIES_EXEC; >> setup_new_exec(bprm); >> + install_exec_creds(bprm); >> set_binfmt(&elf_fdpic_format); >> @@ -434,7 +435,6 @@ static int load_elf_fdpic_binary(struct linux_binprm >> *bprm) >> current->mm->start_stack = current->mm->start_brk + stack_size; >> #endif >> - install_exec_creds(bprm); >> if (create_elf_fdpic_tables(bprm, current->mm, >> &exec_params, &interp_params) < 0) >> goto error; >> diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c >> index 831a2b25ba79..1a1d1fcb893f 100644 >> --- a/fs/binfmt_flat.c >> +++ b/fs/binfmt_flat.c >> @@ -541,6 +541,7 @@ static int load_flat_file(struct linux_binprm *bprm, >> /* OK, This is the point of no return */ >> set_personality(PER_LINUX_32BIT); >> setup_new_exec(bprm); >> + install_exec_creds(bprm); >> } >> /* >> @@ -963,8 +964,6 @@ static int load_flat_binary(struct linux_binprm *bprm) >> } >> } >> - install_exec_creds(bprm); >> - >> set_binfmt(&flat_format); >> #ifdef CONFIG_MMU >>