From patchwork Mon Jun 15 12:12:55 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11604681 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 604E614DD for ; Mon, 15 Jun 2020 12:14:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3EB7B206D7 for ; Mon, 15 Jun 2020 12:14:06 +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="kQj/YptZ" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729930AbgFOMNj (ORCPT ); Mon, 15 Jun 2020 08:13:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45006 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729926AbgFOMNf (ORCPT ); Mon, 15 Jun 2020 08:13:35 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1B41AC061A0E; Mon, 15 Jun 2020 05:13:35 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.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=/uNGWMS6wsKEeNDbdq2MMYM/revZQnG+SE/ig1KbAgs=; b=kQj/YptZTgHtviYD8VY9pDaHTh Nth47/JWS6HPkOCKIBaXf+P0hgcO4QYIwlLm15PzHXiO8z3vDfVw2OZQfftIyksXcjksV6yZ9q0Kz zQPx0MsVBOuBNzzEYpYY/jP8yjvy8CDszcUkg6hJVpCabuI1zJ1tOw9U3oVn+aijjVm8Brck+zI8t yxLxbHcvW5Uj5T74opjNyhohAHs+gDyfJiHUQtXWs8f5Esfe5q3VXOv+tOtjkKBoXS6OdlLXsJ2PB XL4XVX0iMzkEKdQKWmdfmQpCM5qhGYqdDt3Cji/4SSbJXr/IYiiKx+PhQcHwCqo9jFV2EaaSNKFMH vBtD8CzA==; Received: from 195-192-102-148.dyn.cablelink.at ([195.192.102.148] helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jknzY-00074R-9o; Mon, 15 Jun 2020 12:13:32 +0000 From: Christoph Hellwig To: Al Viro Cc: Linus Torvalds , Ian Kent , David Howells , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org, netfilter-devel@vger.kernel.org Subject: [PATCH 11/13] fs: implement kernel_read using __kernel_read Date: Mon, 15 Jun 2020 14:12:55 +0200 Message-Id: <20200615121257.798894-12-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200615121257.798894-1-hch@lst.de> References: <20200615121257.798894-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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 3364fdfc2982b4..e1c471982d6213 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -453,15 +453,12 @@ 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);