linux.git/fs/ecryptfs/ecryptfs_kernel.h, branch v2.6.29

eCryptfs: NULL crypt_stat dereference during lookup

2009-03-22T18:20:43+00:00

If ecryptfs_encrypted_view or ecryptfs_xattr_metadata were being
specified as mount options, a NULL pointer dereference of crypt_stat
was possible during lookup.

This patch moves the crypt_stat assignment into
ecryptfs_lookup_and_interpose_lower(), ensuring that crypt_stat
will not be NULL before we attempt to dereference it.

Thanks to Dan Carpenter and his static analysis tool, smatch, for
finding this bug.

Signed-off-by: Tyler Hicks 
Acked-by: Dustin Kirkland 
Cc: Dan Carpenter 
Cc: Serge Hallyn 
Signed-off-by: Linus Torvalds

eCryptfs: don't encrypt file key with filename key

2009-03-14T18:57:22+00:00

eCryptfs has file encryption keys (FEK), file encryption key encryption
keys (FEKEK), and filename encryption keys (FNEK).  The per-file FEK is
encrypted with one or more FEKEKs and stored in the header of the
encrypted file.  I noticed that the FEK is also being encrypted by the
FNEK.  This is a problem if a user wants to use a different FNEK than
their FEKEK, as their file contents will still be accessible with the
FNEK.

This is a minimalistic patch which prevents the FNEKs signatures from
being copied to the inode signatures list.  Ultimately, it keeps the FEK
from being encrypted with a FNEK.

Signed-off-by: Tyler Hicks 
Cc: Serge Hallyn 
Acked-by: Dustin Kirkland 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

eCryptfs: Filename Encryption: filldir, lookup, and readlink

2009-01-06T23:59:22+00:00

Make the requisite modifications to ecryptfs_filldir(), ecryptfs_lookup(),
and ecryptfs_readlink() to call out to filename encryption functions.
Propagate filename encryption policy flags from mount-wide crypt_stat to
inode crypt_stat.

Signed-off-by: Michael Halcrow 
Cc: Dustin Kirkland 
Cc: Eric Sandeen 
Cc: Tyler Hicks 
Cc: David Kleikamp 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

eCryptfs: Filename Encryption: Header updates

2009-01-06T23:59:21+00:00

Extensions to the header file to support filename encryption.

Signed-off-by: Michael Halcrow 
Cc: Dustin Kirkland 
Cc: Eric Sandeen 
Cc: Tyler Hicks 
Cc: David Kleikamp 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

eCryptfs: Filename Encryption: Tag 70 packets

2009-01-06T23:59:21+00:00

This patchset implements filename encryption via a passphrase-derived
mount-wide Filename Encryption Key (FNEK) specified as a mount parameter.
Each encrypted filename has a fixed prefix indicating that eCryptfs should
try to decrypt the filename.  When eCryptfs encounters this prefix, it
decodes the filename into a tag 70 packet and then decrypts the packet
contents using the FNEK, setting the filename to the decrypted filename.
Both unencrypted and encrypted filenames can reside in the same lower
filesystem.

Because filename encryption expands the length of the filename during the
encoding stage, eCryptfs will not properly handle filenames that are
already near the maximum filename length.

In the present implementation, eCryptfs must be able to produce a match
against the lower encrypted and encoded filename representation when given
a plaintext filename.  Therefore, two files having the same plaintext name
will encrypt and encode into the same lower filename if they are both
encrypted using the same FNEK.  This can be changed by finding a way to
replace the prepended bytes in the blocked-aligned filename with random
characters; they are hashes of the FNEK right now, so that it is possible
to deterministically map from a plaintext filename to an encrypted and
encoded filename in the lower filesystem.  An implementation using random
characters will have to decode and decrypt every single directory entry in
any given directory any time an event occurs wherein the VFS needs to
determine whether a particular file exists in the lower directory and the
decrypted and decoded filenames have not yet been extracted for that
directory.

Thanks to Tyler Hicks and David Kleikamp for assistance in the development
of this patchset.

This patch:

A tag 70 packet contains a filename encrypted with a Filename Encryption
Key (FNEK).  This patch implements functions for writing and parsing tag
70 packets.  This patch also adds definitions and extends structures to
support filename encryption.

Signed-off-by: Michael Halcrow 
Cc: Dustin Kirkland 
Cc: Eric Sandeen 
Cc: Tyler Hicks 
Cc: David Kleikamp 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

CRED: Pass credentials through dentry_open()

2008-11-13T23:39:22+00:00

Pass credentials through dentry_open() so that the COW creds patch can have
SELinux's flush_unauthorized_files() pass the appropriate creds back to itself
when it opens its null chardev.

The security_dentry_open() call also now takes a creds pointer, as does the
dentry_open hook in struct security_operations.

Signed-off-by: David Howells 
Acked-by: James Morris 
Signed-off-by: James Morris

eCryptfs: remove netlink transport

2008-10-16T18:21:39+00:00

The netlink transport code has not worked for a while and the miscdev
transport is a simpler solution.  This patch removes the netlink code and
makes the miscdev transport the only eCryptfs kernel to userspace
transport.

Signed-off-by: Tyler Hicks 
Cc: Michael Halcrow 
Cc: Dustin Kirkland 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

eCryptfs: Make all persistent file opens delayed

2008-07-24T17:47:31+00:00

There is no good reason to immediately open the lower file, and that can
cause problems with files that the user does not intend to immediately
open, such as device nodes.

This patch removes the persistent file open from the interpose step and
pushes that to the locations where eCryptfs really does need the lower
persistent file, such as just before reading or writing the metadata
stored in the lower file header.

Two functions are jumping to out_dput when they should just be jumping to
out on error paths.  This patch also fixes these.

Signed-off-by: Michael Halcrow 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

eCryptfs: do not try to open device files on mknod

2008-07-24T17:47:31+00:00

When creating device nodes, eCryptfs needs to delay actually opening the lower
persistent file until an application tries to open.  Device handles may not be
backed by anything when they first come into existence.

[Valdis.Kletnieks@vt.edu: build fix]
Signed-off-by: Michael Halcrow 
Cc: 
Signed-off-by: Linus Torvalds

eCryptfs: Privileged kthread for lower file opens

2008-07-24T17:47:30+00:00

eCryptfs would really like to have read-write access to all files in the
lower filesystem.  Right now, the persistent lower file may be opened
read-only if the attempt to open it read-write fails.  One way to keep
from having to do that is to have a privileged kthread that can open the
lower persistent file on behalf of the user opening the eCryptfs file;
this patch implements this functionality.

This patch will properly allow a less-privileged user to open the eCryptfs
file, followed by a more-privileged user opening the eCryptfs file, with
the first user only being able to read and the second user being able to
both read and write.  eCryptfs currently does this wrong; it will wind up
calling vfs_write() on a file that was opened read-only.  This is fixed in
this patch.

Signed-off-by: Michael Halcrow 
Cc: Dave Kleikamp 
Cc: Serge Hallyn 
Cc: Eric Sandeen 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds