From patchwork Tue Jul 7 17:47:47 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11649465 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 1EB55912 for ; Tue, 7 Jul 2020 17:48:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0541C2075B for ; Tue, 7 Jul 2020 17:48:27 +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="SGBT2hXu" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728603AbgGGRs0 (ORCPT ); Tue, 7 Jul 2020 13:48:26 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55256 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728573AbgGGRsZ (ORCPT ); Tue, 7 Jul 2020 13:48:25 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA906C061755; Tue, 7 Jul 2020 10:48:24 -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=8oAca2Sh96a0lCcV3gNnPlvoMT0ySVT+lMAbT/xWciU=; b=SGBT2hXuirr0IaFti3lia9tSRU VweNIjq3OrAr2hK/vno0vV+HxxOmSpcmqkNEbPWnvWFYBR1Hr9srSkkQnOHCv4NViyNQtXY3DeDi8 SzPd1dWGgRq1ZgN0uoWxPQMt69bZXzMnxdgpkTV6a1n8KmzCjdFPHNSovZBeantiOow4m6xcubRT/ Frd//4rP24Zf9GPiJo+yqR4k0bGEsBgw9J+d5QKNSPUJLJ/L1xoNykfvJIofZNqn8zAhZIrQNygjV o5dgGljCjpSRBn+hbyV5ijuqsyaCDIsNv3YY9VyBDxWieholZd9mVfoBAPxZ7C3SV4UBv/iEiySD1 8z20ql8A==; 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 1jsrhV-0003IQ-Rs; Tue, 07 Jul 2020 17:48:14 +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 09/23] fs: add a __kernel_read helper Date: Tue, 7 Jul 2020 19:47:47 +0200 Message-Id: <20200707174801.4162712-10-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 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.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 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 | 23 +++++++++++++++++++++++ include/linux/fs.h | 1 + 2 files changed, 24 insertions(+) diff --git a/fs/read_write.c b/fs/read_write.c index bd46c959799e97..cc8e0b4f3cd697 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -430,6 +430,29 @@ 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 (WARN_ON_ONCE(!(file->f_mode & FMODE_READ))) + return -EINVAL; + 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 3f881a892ea746..22cbe7b2e91994 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -3033,6 +3033,7 @@ 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 *);