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=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 08D5FC43218 for ; Sat, 27 Apr 2019 15:28:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D5F0F208CA for ; Sat, 27 Apr 2019 15:28:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728254AbfD0P2f (ORCPT ); Sat, 27 Apr 2019 11:28:35 -0400 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:33078 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727329AbfD0PPV (ORCPT ); Sat, 27 Apr 2019 11:15:21 -0400 Received: from [192.168.4.242] (helo=deadeye) by shadbolt.decadent.org.uk with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.89) (envelope-from ) id 1hKP2s-00014H-DM; Sat, 27 Apr 2019 16:15:18 +0100 Received: from ben by deadeye with local (Exim 4.92) (envelope-from ) id 1hKP2o-0004fH-Am; Sat, 27 Apr 2019 16:15:14 +0100 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, Denis Kirjanov , "Eric W. Biederman" , "Willy Tarreau" , "Oleg Nesterov" , "Robert =?UTF-8?Q?=C5=9Awi=C4=99cki?=" , "Peter Zijlstra" , "Al Viro" , "Kees Cook" , "David Howells" , "Andy Lutomirski" , "Linus Torvalds" Date: Sat, 27 Apr 2019 16:13:09 +0100 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) X-Patchwork-Hint: ignore Subject: [PATCH 3.16 200/202] binfmt_elf: switch to new creds when switching to new mm In-Reply-To: X-SA-Exim-Connect-IP: 192.168.4.242 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 3.16.66-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Linus Torvalds commit 9f834ec18defc369d73ccf9e87a2790bfa05bf46 upstream. We used to delay switching to the new credentials until after we had mapped the executable (and possible elf interpreter). That was kind of odd to begin with, since the new executable will actually then _run_ with the new creds, but whatever. The bigger problem was that we also want to make sure that we turn off prof events and tracing before we start mapping the new executable state. So while this is a cleanup, it's also a fix for a possible information leak. Reported-by: Robert Święcki Tested-by: Peter Zijlstra Acked-by: David Howells Acked-by: Oleg Nesterov Acked-by: Andy Lutomirski Acked-by: Eric W. Biederman Cc: Willy Tarreau Cc: Kees Cook Cc: Al Viro Signed-off-by: Linus Torvalds Signed-off-by: Ben Hutchings --- fs/binfmt_elf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -736,6 +736,7 @@ static int load_elf_binary(struct linux_ current->flags |= PF_RANDOMIZE; setup_new_exec(bprm); + install_exec_creds(bprm); /* Do this so that we can load the interpreter, if need be. We will change some of these later */ @@ -951,7 +952,6 @@ static int load_elf_binary(struct linux_ } #endif /* ARCH_HAS_SETUP_ADDITIONAL_PAGES */ - install_exec_creds(bprm); retval = create_elf_tables(bprm, &loc->elf_ex, load_addr, interp_load_addr); if (retval < 0) {