From: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
To: "Theodore Y. Ts'o" <tytso@mit.edu>,
Jaegeuk Kim <jaegeuk@kernel.org>,
Eric Biggers <ebiggers@kernel.org>, Chris Mason <clm@fb.com>,
Josef Bacik <josef@toxicpanda.com>,
David Sterba <dsterba@suse.com>,
linux-fscrypt@vger.kernel.org, linux-btrfs@vger.kernel.org,
kernel-team@meta.com
Cc: Omar Sandoval <osandov@osandov.com>,
Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
Subject: [PATCH v3 21/22] fscrypt: add flag allowing partially-encrypted directories
Date: Thu, 20 Oct 2022 12:58:40 -0400 [thread overview]
Message-ID: <2664d197270314e809421f58aaeb728df3a3daf4.1666281277.git.sweettea-kernel@dorminy.me> (raw)
In-Reply-To: <cover.1666281276.git.sweettea-kernel@dorminy.me>
From: Omar Sandoval <osandov@osandov.com>
Creating several new subvolumes out of snapshots of another subvolume,
each for a different VM's storage, is a important usecase for btrfs. We
would like to give each VM a unique encryption key to use for new writes
to its subvolume, so that secure deletion of the VM's data is as simple
as securely deleting the key; to avoid needing multiple keys in each VM,
we envision the initial subvolume being unencrypted. However, this means
that the snapshot's directories would have a mix of encrypted and
unencrypted files. During lookup with a key, both unencrypted and
encrypted forms of the desired name must be queried.
To allow this, add another FS_CFLG to allow filesystems to opt into
partially encrypted directories.
Signed-off-by: Omar Sandoval <osandov@osandov.com>
Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me>
---
fs/crypto/fname.c | 17 ++++++++++++++++-
include/linux/fscrypt.h | 2 ++
2 files changed, 18 insertions(+), 1 deletion(-)
diff --git a/fs/crypto/fname.c b/fs/crypto/fname.c
index b3e7e3a66312..16b64e0589e4 100644
--- a/fs/crypto/fname.c
+++ b/fs/crypto/fname.c
@@ -414,6 +414,7 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
fname->usr_fname = iname;
if (!IS_ENCRYPTED(dir) || fscrypt_is_dot_dotdot(iname)) {
+unencrypted:
fname->disk_name.name = (unsigned char *)iname->name;
fname->disk_name.len = iname->len;
return 0;
@@ -448,8 +449,16 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
* user-supplied name
*/
- if (iname->len > FSCRYPT_NOKEY_NAME_MAX_ENCODED)
+ if (iname->len > FSCRYPT_NOKEY_NAME_MAX_ENCODED) {
+ /*
+ * This isn't a valid nokey name, but it could be an unencrypted
+ * name if the filesystem allows partially encrypted
+ * directories.
+ */
+ if (dir->i_sb->s_cop->flags & FS_CFLG_ALLOW_PARTIAL)
+ goto unencrypted;
return -ENOENT;
+ }
fname->crypto_buf.name = kmalloc(FSCRYPT_NOKEY_NAME_MAX, GFP_KERNEL);
if (fname->crypto_buf.name == NULL)
@@ -460,6 +469,12 @@ int fscrypt_setup_filename(struct inode *dir, const struct qstr *iname,
if (ret < (int)offsetof(struct fscrypt_nokey_name, bytes[1]) ||
(ret > offsetof(struct fscrypt_nokey_name, sha256) &&
ret != FSCRYPT_NOKEY_NAME_MAX)) {
+ /* Again, this could be an unencrypted name. */
+ if (dir->i_sb->s_cop->flags & FS_CFLG_ALLOW_PARTIAL) {
+ kfree(fname->crypto_buf.name);
+ fname->crypto_buf.name = NULL;
+ goto unencrypted;
+ }
ret = -ENOENT;
goto errout;
}
diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h
index 4143c722ea1b..485471174594 100644
--- a/include/linux/fscrypt.h
+++ b/include/linux/fscrypt.h
@@ -109,6 +109,8 @@ struct fscrypt_nokey_name {
* pages for writes and therefore won't need the fscrypt bounce page pool.
*/
#define FS_CFLG_OWN_PAGES (1U << 1)
+/* The filesystem allows partially encrypted directories/files. */
+#define FS_CFLG_ALLOW_PARTIAL (1U << 2)
/* Crypto operations for filesystems */
struct fscrypt_operations {
--
2.35.1
next prev parent reply other threads:[~2022-10-20 17:00 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-10-20 16:58 [PATCH v3 00/22] btrfs: add fscrypt integration Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 01/22] fscrypt: expose fscrypt_nokey_name Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 02/22] fscrypt: add fscrypt_have_same_policy() to check inode compatibility Sweet Tea Dorminy
2022-10-20 20:52 ` Josef Bacik
2022-10-20 16:58 ` [PATCH v3 03/22] fscrypt: allow fscrypt_generate_iv() to distinguish filenames Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 04/22] fscrypt: add extent-based encryption Sweet Tea Dorminy
2022-10-20 21:40 ` Eric Biggers
2022-10-20 22:20 ` Sweet Tea Dorminy
2022-10-20 21:45 ` Eric Biggers
2022-10-20 22:55 ` Sweet Tea Dorminy
2022-10-20 23:56 ` Eric Biggers
2022-10-21 0:37 ` Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 05/22] fscrypt: document btrfs' fscrypt quirks Sweet Tea Dorminy
2022-10-20 21:41 ` Eric Biggers
2022-10-20 22:07 ` Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 06/22] btrfs: use struct qstr instead of name and namelen Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 07/22] btrfs: setup qstrings from dentrys using fscrypt helper Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 08/22] btrfs: use struct fscrypt_str instead of struct qstr Sweet Tea Dorminy
2022-10-21 20:42 ` Josef Bacik
2022-10-20 16:58 ` [PATCH v3 09/22] btrfs: store directory encryption state Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 10/22] btrfs: disable various operations on encrypted inodes Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 11/22] btrfs: start using fscrypt hooks Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 12/22] btrfs: add fscrypt_context items Sweet Tea Dorminy
2022-10-21 20:54 ` Josef Bacik
2022-10-20 16:58 ` [PATCH v3 13/22] btrfs: translate btrfs encryption flags and encrypted inode flag Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 14/22] btrfs: store a fscrypt extent context per normal file extent Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 15/22] btrfs: encrypt normal file extent data if appropriate Sweet Tea Dorminy
2022-10-21 20:58 ` Josef Bacik
2022-10-20 16:58 ` [PATCH v3 16/22] btrfs: Add new FEATURE_INCOMPAT_ENCRYPT feature flag Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 17/22] btrfs: implement fscrypt ioctls Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 18/22] btrfs: permit searching for nokey names for removal Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 19/22] btrfs: use correct name hash for nokey names Sweet Tea Dorminy
2022-10-20 16:58 ` [PATCH v3 20/22] btrfs: adapt lookup for partially encrypted directories Sweet Tea Dorminy
2022-10-20 16:58 ` Sweet Tea Dorminy [this message]
2022-10-20 16:58 ` [PATCH v3 22/22] btrfs: encrypt verity items Sweet Tea Dorminy
2022-10-20 21:38 ` [PATCH v3 00/22] btrfs: add fscrypt integration Eric Biggers
2022-10-20 23:12 ` David Sterba
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