From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E44D8C3A59D for ; Fri, 21 Oct 2022 20:54:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230030AbiJUUyc (ORCPT ); Fri, 21 Oct 2022 16:54:32 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230029AbiJUUya (ORCPT ); Fri, 21 Oct 2022 16:54:30 -0400 Received: from mail-qv1-xf2d.google.com (mail-qv1-xf2d.google.com [IPv6:2607:f8b0:4864:20::f2d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EF9C79FEA for ; Fri, 21 Oct 2022 13:54:22 -0700 (PDT) Received: by mail-qv1-xf2d.google.com with SMTP id y10so2634319qvo.11 for ; Fri, 21 Oct 2022 13:54:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=toxicpanda-com.20210112.gappssmtp.com; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=3y577BPV6+vpEshzZdAZIXWdgzTXtiLDG9YfVqSFOr8=; b=ivCoVPzuujWmhS628RxcAM97MUio7oVuZMiX3Gm6r0hGyyS/DNEVjrEOx+8D5IIWZB TamKNu63qVqFMyJWa9nlox17vDg7egJOV6IcyhxAokYP5QXjQgrOBnqoh2VtZZDC9RrY 0hZb/ZDIAngwjTWvPdk3PDjyMkw+3gNlcInLg4pkK/5uh4+hzWVOzBlMLeheaKF+o++y IBGq11tJLvFrn6wCknJKqW3LM+fJcmB084f4YHnRbN/9Tf/CEhU2uQ0OiAQzZ38XNCb/ HMdIb1F9Yivpqh937C51WTiiZThhjFRR/p+wtXvQy4Ana+UhrDbN0uT9xngQ3jjn/+MD Mw5Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=3y577BPV6+vpEshzZdAZIXWdgzTXtiLDG9YfVqSFOr8=; b=wWsczTHbcuU7HLUyq6EHglgnZq2JBy7eQfvkZnHGBL/cnbaaWjcXdnUIdJft10A+Kw Q2sSsojgQWclZot7qy3OcoW9S7V1D7NAPvwi3g5GHzlqVdCRi1QDl3wTi1OpHI6iDI3g xqCsu8JNsAK1Vl8cYfaML+Go/K83AYZCsL7rgYoq/uTsQJCt5nZPnOTPG2kMD71eUQHU J1RBN/7KrNXZjr8wZoH/4QLDjtBYgwK8zq8X3aK9RjQZrtkKuhsp6kYjqDHyHsUHF933 O+w7ufumXcp6XEvmxfTFo2hBez+DexA4/hFEw4l2iBG5GhkTxM04QACb747znCQOHLZi IPHw== X-Gm-Message-State: ACrzQf1ybjlsQvan9Lxq2ncN+NkXqZ+kFZla7EPCqtQQT6Wi5bhDoCRy 6hcQUON75QAIEJCm5zmcLQVaow== X-Google-Smtp-Source: AMsMyM5XXkJ6GzYikUI8sHmyrlkfPg00Yydr68nE5l/EJbaWKMP9SNIp1Z31X4QnX+1Yuj7NsNaL/g== X-Received: by 2002:a05:6214:2aaa:b0:4b1:94e6:6788 with SMTP id js10-20020a0562142aaa00b004b194e66788mr18678205qvb.68.1666385661095; Fri, 21 Oct 2022 13:54:21 -0700 (PDT) Received: from localhost (cpe-174-109-170-245.nc.res.rr.com. [174.109.170.245]) by smtp.gmail.com with ESMTPSA id k11-20020a05620a0b8b00b006ed99931456sm10184492qkh.88.2022.10.21.13.54.19 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 21 Oct 2022 13:54:20 -0700 (PDT) Date: Fri, 21 Oct 2022 16:54:18 -0400 From: Josef Bacik To: Sweet Tea Dorminy Cc: "Theodore Y. Ts'o" , Jaegeuk Kim , Eric Biggers , Chris Mason , David Sterba , linux-fscrypt@vger.kernel.org, linux-btrfs@vger.kernel.org, kernel-team@meta.com, Omar Sandoval Subject: Re: [PATCH v3 12/22] btrfs: add fscrypt_context items Message-ID: References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Oct 20, 2022 at 12:58:31PM -0400, Sweet Tea Dorminy wrote: > From: Omar Sandoval > > In order to store per-inode information such as the inode nonce and the > key identifier, fscrypt stores a context item with each encrypted inode. > This can be implemented as a new item type, as fscrypt provides an > arbitrary blob for the filesystem to store. > > This also provides a good place to implement full-subvolume encryption: > a subvolume flag permits setting one context for the whole subvolume. > However, since an unencrypted subvolume would be unable to read > encrypted data, encrypted subvolumes should only be snapshottable to > other encrypted subvolumes. > > Signed-off-by: Omar Sandoval > Signed-off-by: Sweet Tea Dorminy > --- > fs/btrfs/ctree.h | 1 + > fs/btrfs/fscrypt.c | 170 ++++++++++++++++++++++++++++++++ > fs/btrfs/inode.c | 39 ++++++++ > fs/btrfs/ioctl.c | 7 +- > fs/btrfs/tree-checker.c | 1 + > include/uapi/linux/btrfs_tree.h | 12 +++ > 6 files changed, 229 insertions(+), 1 deletion(-) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 389c4e988318..eb5bbed90e2e 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -32,6 +32,7 @@ > #include "extent-io-tree.h" > #include "extent_io.h" > #include "extent_map.h" > +#include "fscrypt.h" > #include "async-thread.h" > #include "block-rsv.h" > #include "locking.h" > diff --git a/fs/btrfs/fscrypt.c b/fs/btrfs/fscrypt.c > index 48ab99dfe48d..4533ef922d8b 100644 > --- a/fs/btrfs/fscrypt.c > +++ b/fs/btrfs/fscrypt.c > @@ -1,7 +1,177 @@ > // SPDX-License-Identifier: GPL-2.0 > > +#include > #include "ctree.h" > +#include "btrfs_inode.h" > +#include "disk-io.h" > #include "fscrypt.h" > +#include "transaction.h" > +#include "xattr.h" > + > +static int btrfs_fscrypt_get_context(struct inode *inode, void *ctx, size_t len) > +{ > + struct btrfs_root *root = BTRFS_I(inode)->root; > + struct btrfs_key key = { > + .objectid = btrfs_ino(BTRFS_I(inode)), > + .type = BTRFS_FSCRYPT_CTXT_ITEM_KEY, > + .offset = 0, > + }; > + struct inode *put_inode = NULL; > + struct btrfs_path *path; > + struct extent_buffer *leaf; > + unsigned long ptr; > + int ret; > + > + > + if (btrfs_root_flags(&root->root_item) & BTRFS_ROOT_SUBVOL_FSCRYPT) { > + inode = btrfs_iget(inode->i_sb, BTRFS_FIRST_FREE_OBJECTID, > + root); > + if (IS_ERR(inode)) > + return PTR_ERR(inode); > + put_inode = inode; > + } > + > + path = btrfs_alloc_path(); > + if (!path) > + return -ENOMEM; > + > + ret = btrfs_search_slot(NULL, BTRFS_I(inode)->root, &key, path, 0, 0); > + if (ret) { > + len = -EINVAL; > + goto out; > + } > + > + leaf = path->nodes[0]; > + ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); > + /* fscrypt provides max context length, but it could be less */ > + len = min_t(size_t, len, btrfs_item_size(leaf, path->slots[0])); > + read_extent_buffer(leaf, ctx, ptr, len); > + > +out: > + btrfs_free_path(path); > + iput(put_inode); > + return len; > +} > + > +static int btrfs_fscrypt_set_context(struct inode *inode, const void *ctx, > + size_t len, void *fs_data) > +{ > + struct btrfs_root *root = BTRFS_I(inode)->root; > + struct btrfs_trans_handle *trans; > + int is_subvolume = inode->i_ino == BTRFS_FIRST_FREE_OBJECTID; > + int ret; > + struct btrfs_path *path; > + struct btrfs_key key = { > + .objectid = btrfs_ino(BTRFS_I(inode)), > + .type = BTRFS_FSCRYPT_CTXT_ITEM_KEY, > + .offset = 0, > + }; > + > + /* > + * If the whole subvolume is encrypted, we expect that all children > + * have the same policy. > + */ > + if (btrfs_root_flags(&root->root_item) & BTRFS_ROOT_SUBVOL_FSCRYPT) { > + bool same_policy; > + struct inode *root_inode = NULL; > + > + root_inode = btrfs_iget(inode->i_sb, BTRFS_FIRST_FREE_OBJECTID, > + root); > + if (IS_ERR(inode)) > + return PTR_ERR(inode); > + same_policy = fscrypt_have_same_policy(inode, root_inode); > + iput(root_inode); > + if (same_policy) > + return 0; > + } > + > + if (fs_data) { > + /* > + * We are setting the context as part of an existing > + * transaction. This happens when we are inheriting the context > + * for a new inode. > + */ > + trans = fs_data; > + } else { > + /* > + * 1 for the inode item > + * 1 for the fscrypt item > + * 1 for the root item if the inode is a subvolume > + */ > + trans = btrfs_start_transaction(root, 2 + is_subvolume); > + if (IS_ERR(trans)) > + return PTR_ERR(trans); > + } I don't love this, instead lets have a __btrfs_set_fscrypt_context(trans, inode, whatever) and in here you do if (fs_data) return __btrfs_set_fscrypt_context(trans, inode, whatever); trans = btrfs_start_transaction(root, 2 + is_subvolume); ret = __btrfs_set_fscrypt_context(trans, inode, whatever); btrfs_end_transaction(trans); return ret; That'll make this a bit cleaner, especially in the error handling. > + > + path = btrfs_alloc_path(); > + if (!path) > + return -ENOMEM; > + ret = btrfs_search_slot(trans, BTRFS_I(inode)->root, &key, path, 0, 1); > + if (ret == 0) { > + struct extent_buffer *leaf = path->nodes[0]; > + unsigned long ptr = btrfs_item_ptr_offset(leaf, path->slots[0]); > + > + len = min_t(size_t, len, btrfs_item_size(leaf, path->slots[0])); > + write_extent_buffer(leaf, ctx, ptr, len); > + btrfs_mark_buffer_dirty(leaf); > + btrfs_free_path(path); > + goto out; > + } else if (ret < 0) { > + goto out; You're leaking the path in this case. In fact I'd like to see this reworked into a helper since you're only using this to shortcut adding the item if it already exists. Thanks, Josef