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=-7.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no 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 21BA0C433EB for ; Wed, 12 Aug 2020 01:33:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id DB13920829 for ; Wed, 12 Aug 2020 01:33:53 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="JY9HwEL7" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DB13920829 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 857568D002F; Tue, 11 Aug 2020 21:33:53 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7E0248D0001; Tue, 11 Aug 2020 21:33:53 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6F6618D002F; Tue, 11 Aug 2020 21:33:53 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0225.hostedemail.com [216.40.44.225]) by kanga.kvack.org (Postfix) with ESMTP id 5594E8D0001 for ; Tue, 11 Aug 2020 21:33:53 -0400 (EDT) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 22973180AD806 for ; Wed, 12 Aug 2020 01:33:53 +0000 (UTC) X-FDA: 77140195146.22.club71_1902e4f26fe7 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin22.hostedemail.com (Postfix) with ESMTP id EED1018038E67 for ; Wed, 12 Aug 2020 01:33:52 +0000 (UTC) X-HE-Tag: club71_1902e4f26fe7 X-Filterd-Recvd-Size: 3254 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Wed, 12 Aug 2020 01:33:52 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 44CC72087C; Wed, 12 Aug 2020 01:33:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1597196031; bh=iuaLi2FypdCjQV79tqe21ngZf2j5qAR+pxnP+dvjgrQ=; h=Date:From:To:Subject:In-Reply-To:From; b=JY9HwEL7ZtmVdt6v6dV6cnyD4XdZ1kpbi8tBYvGL+LWiWFFJRPLLo84l994L8Ze1i OzRxpiqkLJaNZr4oWtQxXHgWXDsria+4UqrtgSjKETG6UHpI9GbiNRDiBkquYlbJcP Id4ANqVvn/fNGwUFF2fhLHSQ/rVAZO/tczwI2Xks= Date: Tue, 11 Aug 2020 18:33:50 -0700 From: Andrew Morton To: akpm@linux-foundation.org, deanbo422@gmail.com, geert@linux-m68k.org, green.hu@gmail.com, hch@lst.de, linux-mm@kvack.org, mm-commits@vger.kernel.org, nickhu@andestech.com, palmer@dabbelt.com, paul.walmsley@sifive.com, torvalds@linux-foundation.org Subject: [patch 068/165] exec: use force_uaccess_begin during exec and exit Message-ID: <20200812013350.pxHVIskxW%akpm@linux-foundation.org> In-Reply-To: <20200811182949.e12ae9a472e3b5e27e16ad6c@linux-foundation.org> User-Agent: s-nail v14.8.16 X-Rspamd-Queue-Id: EED1018038E67 X-Spamd-Result: default: False [0.00 / 100.00] X-Rspamd-Server: rspam03 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: From: Christoph Hellwig Subject: exec: use force_uaccess_begin during exec and exit Both exec and exit want to ensure that the uaccess routines actually do access user pointers. Use the newly added force_uaccess_begin helper instead of an open coded set_fs for that to prepare for kernel builds where set_fs() does not exist. Link: http://lkml.kernel.org/r/20200710135706.537715-7-hch@lst.de Signed-off-by: Christoph Hellwig Acked-by: Linus Torvalds Cc: Nick Hu Cc: Greentime Hu Cc: Vincent Chen Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Geert Uytterhoeven Signed-off-by: Andrew Morton --- fs/exec.c | 7 ++++++- kernel/exit.c | 2 +- 2 files changed, 7 insertions(+), 2 deletions(-) --- a/fs/exec.c~exec-use-force_uaccess_begin-during-exec-and-exit +++ a/fs/exec.c @@ -1402,7 +1402,12 @@ int begin_new_exec(struct linux_binprm * if (retval) goto out_unlock; - set_fs(USER_DS); + /* + * Ensure that the uaccess routines can actually operate on userspace + * pointers: + */ + force_uaccess_begin(); + me->flags &= ~(PF_RANDOMIZE | PF_FORKNOEXEC | PF_KTHREAD | PF_NOFREEZE | PF_NO_SETAFFINITY); flush_thread(); --- a/kernel/exit.c~exec-use-force_uaccess_begin-during-exec-and-exit +++ a/kernel/exit.c @@ -732,7 +732,7 @@ void __noreturn do_exit(long code) * mm_release()->clear_child_tid() from writing to a user-controlled * kernel address. */ - set_fs(USER_DS); + force_uaccess_begin(); if (unlikely(in_atomic())) { pr_info("note: %s[%d] exited with preempt_count %d\n", _