From patchwork Fri Jun 19 14:33:11 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 223683 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-11.8 required=3.0 tests=DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING, SIGNED_OFF_BY, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1A777C433DF for ; Fri, 19 Jun 2020 16:43:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EBBE821527 for ; Fri, 19 Jun 2020 16:43:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592585010; bh=ZXajvuiMPy9Mi1OaldQr7gj7g5z4w1MmOTv9Xeh694I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=brNg39McvtrlAuMinpClV4/UjYXE0amCniX/JSYapalwdQkHDWpJtm5PE0dALGpI9 Zd15KYj4VUwQNnaLLr/3etulFSDntZTmJBnJDjVSiCB98t2bFK8fVkYWve61mtO9V3 DSxRXwxqS++mLeIxn0XuHahXfQMHKJi3q8czxF8Q= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2395343AbgFSQn1 (ORCPT ); Fri, 19 Jun 2020 12:43:27 -0400 Received: from mail.kernel.org ([198.145.29.99]:34484 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388118AbgFSOnZ (ORCPT ); Fri, 19 Jun 2020 10:43:25 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 4246C2166E; Fri, 19 Jun 2020 14:43:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1592577804; bh=ZXajvuiMPy9Mi1OaldQr7gj7g5z4w1MmOTv9Xeh694I=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=OoWM4CLtzll+fbW/YGUWvRT017RGisfuRVEoeC+1OCe3MbjEhkiaUetuEfkGjX16K rAUuGoNlazdpty9thDiUDEEVg9p4V+t85QS1sXPeCD59p+610hTROyCBjS6yrhq79w zq6ElCcHIKn6MCt1VmY1gFuz8Il37bjvGU8yCEXg= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Filipe Manana , Marcos Paulo de Souza , David Sterba Subject: [PATCH 4.9 097/128] btrfs: send: emit file capabilities after chown Date: Fri, 19 Jun 2020 16:33:11 +0200 Message-Id: <20200619141625.263782215@linuxfoundation.org> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20200619141620.148019466@linuxfoundation.org> References: <20200619141620.148019466@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Sender: stable-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Marcos Paulo de Souza commit 89efda52e6b6930f80f5adda9c3c9edfb1397191 upstream. Whenever a chown is executed, all capabilities of the file being touched are lost. When doing incremental send with a file with capabilities, there is a situation where the capability can be lost on the receiving side. The sequence of actions bellow shows the problem: $ mount /dev/sda fs1 $ mount /dev/sdb fs2 $ touch fs1/foo.bar $ setcap cap_sys_nice+ep fs1/foo.bar $ btrfs subvolume snapshot -r fs1 fs1/snap_init $ btrfs send fs1/snap_init | btrfs receive fs2 $ chgrp adm fs1/foo.bar $ setcap cap_sys_nice+ep fs1/foo.bar $ btrfs subvolume snapshot -r fs1 fs1/snap_complete $ btrfs subvolume snapshot -r fs1 fs1/snap_incremental $ btrfs send fs1/snap_complete | btrfs receive fs2 $ btrfs send -p fs1/snap_init fs1/snap_incremental | btrfs receive fs2 At this point, only a chown was emitted by "btrfs send" since only the group was changed. This makes the cap_sys_nice capability to be dropped from fs2/snap_incremental/foo.bar To fix that, only emit capabilities after chown is emitted. The current code first checks for xattrs that are new/changed, emits them, and later emit the chown. Now, __process_new_xattr skips capabilities, letting only finish_inode_if_needed to emit them, if they exist, for the inode being processed. This behavior was being worked around in "btrfs receive" side by caching the capability and only applying it after chown. Now, xattrs are only emmited _after_ chown, making that workaround not needed anymore. Link: https://github.com/kdave/btrfs-progs/issues/202 CC: stable@vger.kernel.org # 4.4+ Suggested-by: Filipe Manana Reviewed-by: Filipe Manana Signed-off-by: Marcos Paulo de Souza Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman --- fs/btrfs/send.c | 67 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 67 insertions(+) --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -35,6 +35,7 @@ #include "btrfs_inode.h" #include "transaction.h" #include "compression.h" +#include "xattr.h" /* * Maximum number of references an extent can have in order for us to attempt to @@ -4368,6 +4369,10 @@ static int __process_new_xattr(int num, struct fs_path *p; struct posix_acl_xattr_header dummy_acl; + /* Capabilities are emitted by finish_inode_if_needed */ + if (!strncmp(name, XATTR_NAME_CAPS, name_len)) + return 0; + p = fs_path_alloc(); if (!p) return -ENOMEM; @@ -4904,6 +4909,64 @@ static int send_extent_data(struct send_ return 0; } +/* + * Search for a capability xattr related to sctx->cur_ino. If the capability is + * found, call send_set_xattr function to emit it. + * + * Return 0 if there isn't a capability, or when the capability was emitted + * successfully, or < 0 if an error occurred. + */ +static int send_capabilities(struct send_ctx *sctx) +{ + struct fs_path *fspath = NULL; + struct btrfs_path *path; + struct btrfs_dir_item *di; + struct extent_buffer *leaf; + unsigned long data_ptr; + char *buf = NULL; + int buf_len; + int ret = 0; + + path = alloc_path_for_send(); + if (!path) + return -ENOMEM; + + di = btrfs_lookup_xattr(NULL, sctx->send_root, path, sctx->cur_ino, + XATTR_NAME_CAPS, strlen(XATTR_NAME_CAPS), 0); + if (!di) { + /* There is no xattr for this inode */ + goto out; + } else if (IS_ERR(di)) { + ret = PTR_ERR(di); + goto out; + } + + leaf = path->nodes[0]; + buf_len = btrfs_dir_data_len(leaf, di); + + fspath = fs_path_alloc(); + buf = kmalloc(buf_len, GFP_KERNEL); + if (!fspath || !buf) { + ret = -ENOMEM; + goto out; + } + + ret = get_cur_path(sctx, sctx->cur_ino, sctx->cur_inode_gen, fspath); + if (ret < 0) + goto out; + + data_ptr = (unsigned long)(di + 1) + btrfs_dir_name_len(leaf, di); + read_extent_buffer(leaf, buf, data_ptr, buf_len); + + ret = send_set_xattr(sctx, fspath, XATTR_NAME_CAPS, + strlen(XATTR_NAME_CAPS), buf, buf_len); +out: + kfree(buf); + fs_path_free(fspath); + btrfs_free_path(path); + return ret; +} + static int clone_range(struct send_ctx *sctx, struct clone_root *clone_root, const u64 disk_byte, @@ -5615,6 +5678,10 @@ static int finish_inode_if_needed(struct goto out; } + ret = send_capabilities(sctx); + if (ret < 0) + goto out; + /* * If other directory inodes depended on our current directory * inode's move/rename, now do their move/rename operations.