From patchwork Fri May 8 09:22:18 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11536111 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 9AC78913 for ; Fri, 8 May 2020 09:23:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7669921582 for ; Fri, 8 May 2020 09:23:06 +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="p26D5tuX" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727786AbgEHJWn (ORCPT ); Fri, 8 May 2020 05:22:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56568 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727780AbgEHJWn (ORCPT ); Fri, 8 May 2020 05:22:43 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 058F7C05BD43; Fri, 8 May 2020 02:22:43 -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=2xa/wiG5agEUFc0wQaCp1rgH/MqxYHnGtxkOZ1B6lq8=; b=p26D5tuXJEYyjY6ZosGiYBDB3E 1nq9PJ5KJeCChaYv93o+077l05GSOwqJwF9js9042LPhMGecjuUw3dSEd2lBlM2vKuXbHEs0gsisq 2O36MwsQAOBupXMVoqH4mu6d6eRo2O6pbGMg2XtWDpUmNueG88exR3Bs90oRCAiVNaZg6Zp8HMyid +zvsgsCGSVci3FwA9zH/YN/KDCYr5X+/IG8NMXSRU1pCN1D2V/z0tR5AULuo4aJITTLkT05Pn0kBK NH6igeEEFYWgwB/VtYEPddtbFsH57WTUTKFzvpOLCD0xSrVlwHlMa1l96ijBep7ssATWjLZz5Jmcw 4GyQbx2A==; Received: from [2001:4bb8:180:9d3f:90d7:9df8:7cd:3504] (helo=localhost) by bombadil.infradead.org with esmtpsa (Exim 4.92.3 #3 (Red Hat Linux)) id 1jWzDO-0008TT-Go; Fri, 08 May 2020 09:22:42 +0000 From: Christoph Hellwig To: Al Viro Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-security-module@vger.kernel.org Subject: [PATCH 07/11] fs: add a __kernel_read helper Date: Fri, 8 May 2020 11:22:18 +0200 Message-Id: <20200508092222.2097-8-hch@lst.de> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20200508092222.2097-1-hch@lst.de> References: <20200508092222.2097-1-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: owner-linux-security-module@vger.kernel.org Precedence: bulk List-ID: This is the counterpart to __kernel_write, and skip the rw_verify_area call compared to kernel_read. Signed-off-by: Christoph Hellwig --- fs/read_write.c | 21 +++++++++++++++++++++ include/linux/fs.h | 1 + 2 files changed, 22 insertions(+) diff --git a/fs/read_write.c b/fs/read_write.c index 8a55e81bd9ac7..93f5724b4837d 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -430,6 +430,27 @@ ssize_t __vfs_read(struct file *file, char __user *buf, size_t count, return -EINVAL; } +ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) +{ + mm_segment_t old_fs = get_fs(); + ssize_t ret; + + if (!(file->f_mode & FMODE_CAN_READ)) + return -EINVAL; + + if (count > MAX_RW_COUNT) + count = MAX_RW_COUNT; + set_fs(KERNEL_DS); + ret = __vfs_read(file, (void __user *)buf, count, pos); + set_fs(old_fs); + if (ret > 0) { + fsnotify_access(file); + add_rchar(current, ret); + } + inc_syscr(current); + return ret; +} + ssize_t kernel_read(struct file *file, void *buf, size_t count, loff_t *pos) { mm_segment_t old_fs; diff --git a/include/linux/fs.h b/include/linux/fs.h index 21f126957c2cf..6441aaa25f8f2 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3011,6 +3011,7 @@ extern int kernel_read_file_from_path_initns(const char *, void **, loff_t *, lo extern int kernel_read_file_from_fd(int, void **, loff_t *, loff_t, enum kernel_read_file_id); extern ssize_t kernel_read(struct file *, void *, size_t, loff_t *); +ssize_t __kernel_read(struct file *file, void *buf, size_t count, loff_t *pos); extern ssize_t kernel_write(struct file *, const void *, size_t, loff_t *); extern ssize_t __kernel_write(struct file *, const void *, size_t, loff_t *); extern struct file * open_exec(const char *);