From patchwork Wed Jun 24 16:13:32 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11623655 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 3784E60D for ; Wed, 24 Jun 2020 16:14:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 15CF020768 for ; Wed, 24 Jun 2020 16:14:55 +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="YB66beWO" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404546AbgFXQOc (ORCPT ); Wed, 24 Jun 2020 12:14:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38698 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2404846AbgFXQOO (ORCPT ); Wed, 24 Jun 2020 12:14:14 -0400 Received: from casper.infradead.org (unknown [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D9C40C061796; Wed, 24 Jun 2020 09:14:13 -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=YB66beWOM8rLRQIjm3q1TqZJBC vflHEfvmWfS43Nb8HKAhtLHQdK6g2/Unssp2DZGrYtBVMAgO+i7da/bCwoX5pxMNfUmSECCFYXPFt 8VoeXBYA6E4KtmJaaiivhK3+YsuOGyG6IGO6HTfOolB2Yh4TlUb1rQkIxJN1CAqlj5fEXVhLIWl+A 9Av9Oup4gxm7V/a2w3TiALvTA1dT352cwzmU8rRHU84XguyObJpzSQmNGpUgGruVAQ7H9CophvWTp 1GRQrXzlzJ55RB4fv2qgulET3KsCT4P48Uj82dOR9TIxqug7D+a4axHIFBXvJlXzp3wElpvlLdL0M sayusasQ==; Received: from [2001:4bb8:180:a3:5c7c:8955:539d:955b] (helo=localhost) by casper.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jo822-0005z6-OR; Wed, 24 Jun 2020 16:13:51 +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 11/14] fs: implement kernel_read using __kernel_read Date: Wed, 24 Jun 2020 18:13:32 +0200 Message-Id: <20200624161335.1810359-12-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200624161335.1810359-1-hch@lst.de> References: <20200624161335.1810359-1-hch@lst.de> MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Sender: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: 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);