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=-12.8 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 51D49C433DF for ; Tue, 14 Jul 2020 11:10:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1FCFD2075B for ; Tue, 14 Jul 2020 11:10:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="I23oUhor" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727844AbgGNLKf (ORCPT ); Tue, 14 Jul 2020 07:10:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726252AbgGNLKe (ORCPT ); Tue, 14 Jul 2020 07:10:34 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 63AFEC061755; Tue, 14 Jul 2020 04:10:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Transfer-Encoding:MIME-Version: References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To: Content-Type:Content-ID:Content-Description; bh=aA679qIodiBpC5vbULiwbVKx3fOumlOYyYuEKhecoTI=; b=I23oUhorQvkUc3pKxqW65dWZKi 2fvnRyOEcYQiwRX71KaxF5fb1WDG9GhMZ0whjJ4vniWBpxRO+H4GEqTsMWqFwK88N8jITuk5W5dzq 964ngvwoNriO55HokZ0KVUAATgpYwv7/l2gjlugolwHLuVj7WlJlE//60NlcNcyzqauvWByDcKjSJ 7Fv51WGpAXn+LU5rCKIO7zOLWNs/SrNcTp5pWrbsbYxma8sEaB72+1iDJlLGTd2VnQ97nIKoe1xMK eTx5w1U1nwg7BYSroNLCMEwFnKIR79GysRyZxtpMg5ya2xRvud3GD+pkGvH1WKaGvX+CzkoWoN/aS XwKN5xUQ==; Received: from 089144201169.atnat0010.highway.a1.net ([89.144.201.169] helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jvIpP-0006Ta-Mr; Tue, 14 Jul 2020 11:10:28 +0000 From: Christoph Hellwig To: Nick Hu , Greentime Hu , Vincent Chen , Paul Walmsley , Palmer Dabbelt , Andrew Morton , Linus Torvalds Cc: linux-riscv@lists.infradead.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 6/6] exec: use force_uaccess_begin during exec and exit Date: Tue, 14 Jul 2020 12:55:05 +0200 Message-Id: <20200714105505.935079-7-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200714105505.935079-1-hch@lst.de> References: <20200714105505.935079-1-hch@lst.de> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. Signed-off-by: Christoph Hellwig --- fs/exec.c | 7 ++++++- kernel/exit.c | 2 +- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/fs/exec.c b/fs/exec.c index e6e8a9a7032784..769af470b69124 100644 --- a/fs/exec.c +++ b/fs/exec.c @@ -1380,7 +1380,12 @@ int begin_new_exec(struct linux_binprm * bprm) 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(); diff --git a/kernel/exit.c b/kernel/exit.c index 727150f2810338..17d486a20f0dc6 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -731,7 +731,7 @@ 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", -- 2.26.2