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=-9.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 07184C433DF for ; Tue, 7 Jul 2020 17:49:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CB7DD20675 for ; Tue, 7 Jul 2020 17:49:29 +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="FedC0yES" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728840AbgGGRt2 (ORCPT ); Tue, 7 Jul 2020 13:49:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55220 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728440AbgGGRsQ (ORCPT ); Tue, 7 Jul 2020 13:48:16 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D8347C08C5DC; Tue, 7 Jul 2020 10:48:15 -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=Hlt6C7VzRXUPvzt04ubxLGUKBtxCCqCnw0SDgIXm7hw=; b=FedC0yESTcWwLvcjowIvzYO5kq 8Yla9CQhhoM/P0NsCRc27TI/uwOMB4Zu/E/moc4ndCkdSL7NkZRiZMhNHYrIC5HR0iFKw+/WysYlI yZKTU4iq0Np4TKJJZDx8/A0D8+hrnzF+IVbTcB7rw9YU/aVnsKslNf0hm1+6xDktO2bLaOsdc4xhk 6keJC5+QACVIp2qX070sCpAyFI0oF6XVXLkh/QuNi0zDp6m+WrKDhNMqhg4NFP9GFON81Kjc3yvDI Si1EG5LTZeEpStd9gD/5Y2Oj0TeN8zngapPPA0yjHU2vsIEebH/UdlL3HVwENCxTE9DtEbr7R06Se FIxz2vBA==; Received: from [2001:4bb8:18c:3b3b:a49f:8154:a2b7:8b6c] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jsrhS-0003Hj-Fn; Tue, 07 Jul 2020 17:48:10 +0000 From: Christoph Hellwig To: Al Viro , Linus Torvalds , Stephen Rothwell Cc: Luis Chamberlain , Matthew Wilcox , Kees Cook , Iurii Zaikin , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 06/23] fs: implement kernel_write using __kernel_write Date: Tue, 7 Jul 2020 19:47:44 +0200 Message-Id: <20200707174801.4162712-7-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200707174801.4162712-1-hch@lst.de> References: <20200707174801.4162712-1-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 Consolidate the two in-kernel write helpers to make upcoming changes easier. The only difference are the missing call to rw_verify_area in kernel_write, and an access_ok check that doesn't make sense for kernel buffers to start with. Signed-off-by: Christoph Hellwig --- fs/read_write.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index 8f9fc05990ae8b..5110cd1e6e2771 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -499,6 +499,7 @@ static ssize_t __vfs_write(struct file *file, const char __user *p, return -EINVAL; } +/* caller is responsible for file_start_write/file_end_write */ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos) { mm_segment_t old_fs; @@ -528,16 +529,16 @@ ssize_t __kernel_write(struct file *file, const void *buf, size_t count, loff_t ssize_t kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos) { - mm_segment_t old_fs; - ssize_t res; + ssize_t ret; - old_fs = get_fs(); - set_fs(KERNEL_DS); - /* The cast to a user pointer is valid due to the set_fs() */ - res = vfs_write(file, (__force const char __user *)buf, count, pos); - set_fs(old_fs); + ret = rw_verify_area(WRITE, file, pos, count); + if (ret) + return ret; - return res; + file_start_write(file); + ret = __kernel_write(file, buf, count, pos); + file_end_write(file); + return ret; } EXPORT_SYMBOL(kernel_write); -- 2.26.2