Provide an option to provide a view of the encrypted files such that the
metadata is always in the header of the files, regardless of whether the
metadata is actually in the header or in the extended attribute. This mode of
operation is useful for applications like incremental backup utilities that do
not preserve the extended attributes when directly accessing the lower files.
With this option enabled, the files under the eCryptfs mount point will be
read-only.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Generalize the metadata reading and writing mechanisms, with two targets for
now: metadata in file header and metadata in the user.ecryptfs xattr of the
lower file.
[akpm@osdl.org: printk warning fix]
[bunk@stusta.de: make some needlessly global code static]
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch set introduces the ability to store cryptographic metadata into an
lower file extended attribute rather than the lower file header region.
This patch set implements two new mount options:
ecryptfs_xattr_metadata
- When set, newly created files will have their cryptographic
metadata stored in the extended attribute region of the file rather
than the header.
When storing the data in the file header, there is a minimum of 8KB
reserved for the header information for each file, making each file at
least 12KB in size. This can take up a lot of extra disk space if the user
creates a lot of small files. By storing the data in the extended
attribute, each file will only occupy at least of 4KB of space.
As the eCryptfs metadata set becomes larger with new features such as
multi-key associations, most popular filesystems will not be able to store
all of the information in the xattr region in some cases due to space
constraints. However, the majority of users will only ever associate one
key per file, so most users will be okay with storing their data in the
xattr region.
This option should be used with caution. I want to emphasize that the
xattr must be maintained under all circumstances, or the file will be
rendered permanently unrecoverable. The last thing I want is for a user to
forget to set an xattr flag in a backup utility, only to later discover
that their backups are worthless.
ecryptfs_encrypted_view
- When set, this option causes eCryptfs to present applications a
view of encrypted files as if the cryptographic metadata were
stored in the file header, whether the metadata is actually stored
in the header or in the extended attributes.
No matter what eCryptfs winds up doing in the lower filesystem, I want
to preserve a baseline format compatibility for the encrypted files. As of
right now, the metadata may be in the file header or in an xattr. There is
no reason why the metadata could not be put in a separate file in future
versions.
Without the compatibility mode, backup utilities would have to know to
back up the metadata file along with the files. The semantics of eCryptfs
have always been that the lower files are self-contained units of encrypted
data, and the only additional information required to decrypt any given
eCryptfs file is the key. That is what has always been emphasized about
eCryptfs lower files, and that is what users expect. Providing the
encrypted view option will provide a way to userspace applications wherein
they can always get to the same old familiar eCryptfs encrypted files,
regardless of what eCryptfs winds up doing with the metadata behind the
scenes.
This patch:
Add extended attribute support to version bit vector, flags to indicate when
xattr or encrypted view modes are enabled, and support for the new mount
options.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Replace appropriate pairs of "kmem_cache_alloc()" + "memset(0)" with the
corresponding "kmem_cache_zalloc()" call.
Signed-off-by: Robert P. J. Day <rpjday@mindspring.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Roland McGrath <roland@redhat.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Greg KH <greg@kroah.com>
Acked-by: Joel Becker <Joel.Becker@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
SLAB_KERNEL is an alias of GFP_KERNEL.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
SLAB_USER is an alias of GFP_USER
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The return value of crypto_alloc_blkcipher() should be checked by IS_ERR().
Cc: Mike Halcrow <mhalcrow@us.ibm.com>
Cc: Phillip Hellewell <phillip@hellewell.homeip.net>
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I missed a pointer dereference in this kmalloc result check.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Opens on lower dentry objects happen in several places in eCryptfs, and they
all involve the same steps (dget, mntget, dentry_open). This patch
consolidates the lower open events into a single function call.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Update cipher block encryption code to the new crypto API.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Update eCryptfs hash code to the new kernel crypto API.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Clean up the crypto initialization code; let the crypto API take care of the
key size checks.
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
eCryptfs is a stacked cryptographic filesystem for Linux. It is derived from
Erez Zadok's Cryptfs, implemented through the FiST framework for generating
stacked filesystems. eCryptfs extends Cryptfs to provide advanced key
management and policy features. eCryptfs stores cryptographic metadata in the
header of each file written, so that encrypted files can be copied between
hosts; the file will be decryptable with the proper key, and there is no need
to keep track of any additional information aside from what is already in the
encrypted file itself.
[akpm@osdl.org: updates for ongoing API changes]
[bunk@stusta.de: cleanups]
[akpm@osdl.org: alpha build fix]
[akpm@osdl.org: cleanups]
[tytso@mit.edu: inode-diet updates]
[pbadari@us.ibm.com: generic_file_*_read/write() interface updates]
[rdunlap@xenotime.net: printk format fixes]
[akpm@osdl.org: make slab creation and teardown table-driven]
Signed-off-by: Phillip Hellewell <phillip@hellewell.homeip.net>
Signed-off-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
Signed-off-by: Adrian Bunk <bunk@stusta.de>
Signed-off-by: Stephan Mueller <smueller@chronox.de>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
