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=-9.8 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,URIBL_BLOCKED,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 8A00EC433DF for ; Wed, 1 Jul 2020 20:24:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5D11D20853 for ; Wed, 1 Jul 2020 20:24:33 +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="aedw4ZQA" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728080AbgGAUYb (ORCPT ); Wed, 1 Jul 2020 16:24:31 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49294 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727808AbgGAUXQ (ORCPT ); Wed, 1 Jul 2020 16:23:16 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 81906C08C5DB; Wed, 1 Jul 2020 13:23:16 -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=rF/h+g2aRvM7O684xTgcwq5WjNPNPSLZJBoCztHySj0=; b=aedw4ZQA9cALo1d9Fp8GNOr9x3 k649IpCT0RA/ne2b3RtpmrOzHi6W3FeKeC4PQfgH8kNAfT35neIdZh25E9QbST3rTCXa0nl3O7Pju kU9MHR9ZwCKFxoLSNpZm8z5LGgyvqc1eY19pSFbAYsBj0tdB5RualLR4XzcFGoNTENKsxEXWjBG/u EJatLufQ7K1LWzq/q/AVdfpQphY4aRemIktioa/R4FAcIHvyfNJU4OsmX6q+uRZ7tTVvtjFiuuqV+ kFyH3XgwNfFcDbSUfY2l7kP0+/sImjO74n+1vXl1KRUDwoVaBfuzBeBsbfiIDAjvKV6vY17TreB3P vZf+8drA==; Received: from [2001:4bb8:18c:3b3b:379a:a079:66b5:89c3] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jqjGB-0002QY-0d; Wed, 01 Jul 2020 20:23:11 +0000 From: Christoph Hellwig To: Al Viro , Linus Torvalds Cc: Luis Chamberlain , Matthew Wilcox , Kees Cook , Iurii Zaikin , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Subject: [PATCH 11/23] fs: implement kernel_read using __kernel_read Date: Wed, 1 Jul 2020 22:09:39 +0200 Message-Id: <20200701200951.3603160-12-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200701200951.3603160-1-hch@lst.de> References: <20200701200951.3603160-1-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 read helpers to make upcoming changes easier. The only difference are the missing call to rw_verify_area in kernel_read, 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 | 13 +++++-------- 1 file changed, 5 insertions(+), 8 deletions(-) diff --git a/fs/read_write.c b/fs/read_write.c index cc8e0b4f3cd697..a0a0b5d1d9249c 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -455,15 +455,12 @@ ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) { - mm_segment_t old_fs; - ssize_t result; + ssize_t ret; - old_fs = get_fs(); - set_fs(KERNEL_DS); - /* The cast to a user pointer is valid due to the set_fs() */ - result = vfs_read(file, (void __user *)buf, count, pos); - set_fs(old_fs); - return result; + ret = rw_verify_area(READ, file, pos, count); + if (ret) + return ret; + return __kernel_read(file, buf, count, pos); } EXPORT_SYMBOL(kernel_read); -- 2.26.2