From patchwork Fri May 8 09:22:15 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Christoph Hellwig X-Patchwork-Id: 11536121 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 27A6C159A for ; Fri, 8 May 2020 09:23:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 076B3208DB for ; Fri, 8 May 2020 09:23:16 +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="I2fV/Il/" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727100AbgEHJWh (ORCPT ); Fri, 8 May 2020 05:22:37 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56544 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727095AbgEHJWf (ORCPT ); Fri, 8 May 2020 05:22:35 -0400 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:e::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E100C05BD43; Fri, 8 May 2020 02:22:35 -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=/Vw1xBDqcg+had1H7ldfhCCl+Ssv4JonY1VaXlhtXBk=; b=I2fV/Il/XU+eajjiZQcidKGoMT QP56q4Zq+TTHB6ncYlzWGgrpbxz/uo9TmD78E/YEV0jmqMMkBZVYJZIntxXpZfkLbPa4d7mth9gUn jL9SFH0ecXzMGl24/Jr7EUTaNpPsHZVuoHecEHc1rrZ6iVoRTtJifMi5x9wsVtXzbtr2rzQY3JUYD VScP/8znNa9NNBap7UDX3bA8i7GgKHkmUaAtJ6Gs/LAj+D5O3sakvOdDonXtn/i0F9csiafQ15TOy 1kfHXRJWsiFsUb22CIeRZHzRx6fsUz9VlHejkw2ivZBeLYbXlJTmf8KOYI9nW1DizG07e2Z6vTpOJ Bie1R+kQ==; 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 1jWzDG-0008KE-UI; Fri, 08 May 2020 09:22:35 +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 04/11] fs: implement kernel_write using __kernel_write Date: Fri, 8 May 2020 11:22:15 +0200 Message-Id: <20200508092222.2097-5-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: Consolidate the two in-kernel write helpers to make upcoming changes easier. The only difference are the missing call to rw_verify_area in kernel_write, 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 d91fe7ff6cc55..6b456a257b31c 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -531,16 +531,13 @@ EXPORT_SYMBOL(__kernel_write); ssize_t kernel_write(struct file *file, const void *buf, size_t count, loff_t *pos) { - mm_segment_t old_fs; - ssize_t res; - old_fs = get_fs(); - set_fs(KERNEL_DS); - /* The cast to a user pointer is valid due to the set_fs() */ - res = vfs_write(file, (__force const char __user *)buf, count, pos); - set_fs(old_fs); + ssize_t ret; - return res; + ret = rw_verify_area(WRITE, file, pos, count); + if (ret) + return ret; + return __kernel_write(file, buf, count, pos); } EXPORT_SYMBOL(kernel_write);