Make the switch from the blkcipher kernel crypto interface to the
ablkcipher interface.

encrypt_scatterlist() and decrypt_scatterlist() now use the ablkcipher
interface but, from the eCryptfs standpoint, still treat the crypto
operation as a synchronous operation. They submit the async request and
then wait until the operation is finished before they return. Most of
the changes are contained inside those two functions.

Despite waiting for the completion of the crypto operation, the
ablkcipher interface provides performance increases in most cases when
used on AES-NI capable hardware.
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Acked-by: NColin King <colin.king@canonical.com>
Reviewed-by: NZeev Zilberman <zeev@annapurnaLabs.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Cc: Tim Chen <tim.c.chen@intel.com>
Cc: Ying Huang <ying.huang@intel.com>
Cc: Thieu Le <thieule@google.com>
Cc: Li Wang <dragonylffly@163.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@iki.fi>

When the userspace messaging (for the less common case of userspace key
wrap/unwrap via ecryptfsd) is not needed, allow eCryptfs to build with
it removed. This saves on kernel code size and reduces potential attack
surface by removing the /dev/ecryptfs node.
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

... and keep the sodding requests on stack - they are small enough.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Historically, eCryptfs has only initialized lower files in the
ecryptfs_create() path. Lower file initialization is the act of writing
the cryptographic metadata from the inode's crypt_stat to the header of
the file. The ecryptfs_open() path already expects that metadata to be
in the header of the file.

A number of users have reported empty lower files in beneath their
eCryptfs mounts. Most of the causes for those empty files being left
around have been addressed, but the presence of empty files causes
problems due to the lack of proper cryptographic metadata.

To transparently solve this problem, this patch initializes empty lower
files in the ecryptfs_open() error path. If the metadata is unreadable
due to the lower inode size being 0, plaintext passthrough support is
not in use, and the metadata is stored in the header of the file (as
opposed to the user.ecryptfs extended attribute), the lower file will be
initialized.

The number of nested conditionals in ecryptfs_open() was getting out of
hand, so a helper function was created. To avoid the same nested
conditional problem, the conditional logic was reversed inside of the
helper function.

https://launchpad.net/bugs/911507Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Cc: John Johansen <john.johansen@canonical.com>
Cc: Colin Ian King <colin.king@canonical.com>

Now that a pointer to a valid struct ecryptfs_daemon is stored in the
private_data of an opened /dev/ecryptfs file, the remaining miscdev
functions can utilize the pointer rather than looking up the
ecryptfs_daemon at the beginning of each operation.

The security model of /dev/ecryptfs is simplified a little bit with this
patch. Upon opening /dev/ecryptfs, a per-user ecryptfs_daemon is
registered. Another daemon cannot be registered for that user until the
last file reference is released. During the lifetime of the
ecryptfs_daemon, access checks are not performed on the /dev/ecryptfs
operations because it is assumed that the application securely handles
the opened file descriptor and does not unintentionally leak it to
processes that are not trusted.
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Cc: Sasha Levin <levinsasha928@gmail.com>

These are no longer needed.
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Cc: Sasha Levin <levinsasha928@gmail.com>

statfs() calls on eCryptfs files returned the wrong filesystem type and,
when using filename encryption, the wrong maximum filename length.

If mount-wide filename encryption is enabled, the cipher block size and
the lower filesystem's max filename length will determine the max
eCryptfs filename length. Pre-tested, known good lengths are used when
the lower filesystem's namelen is 255 and a cipher with 8 or 16 byte
block sizes is used. In other, less common cases, we fall back to a safe
rounded-down estimate when determining the eCryptfs namelen.

https://launchpad.net/bugs/885744Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Reported-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NKees Cook <keescook@chromium.org>
Reviewed-by: NJohn Johansen <john.johansen@canonical.com>

ecryptfs_miscdev_read() and ecryptfs_miscdev_write() contained many
magic numbers for specifying packet header field sizes and offsets. This
patch defines those values and replaces the magic values.
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>

The file creation path prematurely called d_instantiate() and
unlock_new_inode() before the eCryptfs inode info was fully
allocated and initialized and before the eCryptfs metadata was written
to the lower file.

This could result in race conditions in subsequent file and inode
operations leading to unexpected error conditions or a null pointer
dereference while attempting to use the unallocated memory.

https://launchpad.net/bugs/813146Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Cc: stable@kernel.org

Standardize the style for compiler based printf format verification.
Standardized the location of __printf too.

Done via script and a little typing.

$ grep -rPl --include=*.[ch] -w "__attribute__" * | \
  grep -vP "^(tools|scripts|include/linux/compiler-gcc.h)" | \
  xargs perl -n -i -e 'local $/; while (<>) { s/\b__attribute__\s*\(\s*\(\s*format\s*\(\s*printf\s*,\s*(.+)\s*,\s*(.+)\s*\)\s*\)\s*\)/__printf($1, $2)/g ; print; }'

[akpm@linux-foundation.org: revert arch bits]
Signed-off-by: NJoe Perches <joe@perches.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The function ecryptfs_keyring_auth_tok_for_sig() has been modified in order
to search keys of both 'user' and 'encrypted' types.
Signed-off-by: NRoberto Sassu <roberto.sassu@polito.it>
Acked-by: NGianluca Ramunno <ramunno@polito.it>
Acked-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Some eCryptfs specific definitions, such as the current version and the
authentication token structure, are moved to the new include file
'include/linux/ecryptfs.h', in order to be available for all kernel
subsystems.
Signed-off-by: NRoberto Sassu <roberto.sassu@polito.it>
Acked-by: NGianluca Ramunno <ramunno@polito.it>
Acked-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NMimi Zohar <zohar@linux.vnet.ibm.com>

Now that ecryptfs_lookup_interpose() is no longer using
ecryptfs_header_cache_2 to read in metadata, the kmem_cache can be
removed and the ecryptfs_header_cache_1 kmem_cache can be renamed to
ecryptfs_header_cache.
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

ecryptfs_lookup_interpose() has turned into spaghetti code over the
years. This is an effort to clean it up.

 - Shorten overly descriptive variable names such as ecryptfs_dentry
 - Simplify gotos and error paths
 - Create helper function for reading plaintext i_size from metadata

It also includes an optimization when reading i_size from the metadata.
A complete page-sized kmem_cache_alloc() was being done to read in 16
bytes of metadata. The buffer for that is now statically declared.
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Only unlock and d_add() new inodes after the plaintext inode size has
been read from the lower filesystem. This fixes a race condition that
was sometimes seen during a multi-job kernel build in an eCryptfs mount.

https://bugzilla.kernel.org/show_bug.cgi?id=36002Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>
Reported-by: NDavid <david@unsolicited.net>
Tested-by: NDavid <david@unsolicited.net>

The eCryptfs inode get, initialization, and dentry interposition code
has two separate paths. One is for when dentry interposition is needed
after doing things like a mkdir in the lower filesystem and the other
is needed after a lookup. Unlocking new inodes and doing a d_add() needs
to happen at different times, depending on which type of dentry
interposing is being done.

This patch cleans up the inode get and initialization code paths and
splits them up so that the locking and d_add() differences mentioned
above can be handled appropriately in a later patch.
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>
Tested-by: NDavid <david@unsolicited.net>

These functions should live in inode.c since their focus is on inodes
and they're primarily used by functions in inode.c.

Also does a simple cleanup of ecryptfs_inode_test() and rolls
ecryptfs_init_inode() into ecryptfs_inode_set().
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>
Tested-by: NDavid <david@unsolicited.net>

When failing to read the lower file's crypto metadata during a lookup,
eCryptfs must continue on without throwing an error. For example, there
may be a plaintext file in the lower mount point that the user wants to
delete through the eCryptfs mount.

If an error is encountered while reading the metadata in lookup(), the
eCryptfs inode's size could be incorrect. We must be sure to reread the
plaintext inode size from the metadata when performing an open() or
setattr(). The metadata is already being read in those paths, so this
adds minimal performance overhead.

This patch introduces a flag which will track whether or not the
plaintext inode size has been read so that an incorrect i_size can be
fixed in the open() or setattr() paths.

https://bugs.launchpad.net/bugs/509180

Cc: <stable@kernel.org>
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

For any given lower inode, eCryptfs keeps only one lower file open and
multiplexes all eCryptfs file operations through that lower file. The
lower file was considered "persistent" and stayed open from the first
lookup through the lifetime of the inode.

This patch keeps the notion of a single, per-inode lower file, but adds
reference counting around the lower file so that it is closed when not
currently in use. If the reference count is at 0 when an operation (such
as open, create, etc.) needs to use the lower file, a new lower file is
opened. Since the file is no longer persistent, all references to the
term persistent file are changed to lower file.

Locking is added around the sections of code that opens the lower file
and assign the pointer in the inode info, as well as the code the fputs
the lower file when all eCryptfs users are done with it.

This patch is needed to fix issues, when mounted on top of the NFSv3
client, where the lower file is left silly renamed until the eCryptfs
inode is destroyed.
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Authentication tokens content may change if another requestor calls the
update() method of the corresponding key. The new function
ecryptfs_verify_auth_tok_from_key() retrieves the authentication token from
the provided key and verifies if it is still valid before being used to
encrypt or decrypt an eCryptfs file.
Signed-off-by: NRoberto Sassu <roberto.sassu@polito.it>
[tyhicks: Minor formatting changes]
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

The size of the 'keysig' array is incremented of one byte in order to make
room for the NULL character. The 'keysig' variable is used, in the function
ecryptfs_generate_key_packet_set(), to find an authentication token with
the given signature and is printed a debug message if it cannot be
retrieved.
Signed-off-by: NRoberto Sassu <roberto.sassu@polito.it>
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

This patch removes the 'num_global_auth_toks' field of the
ecryptfs_mount_crypt_stat structure, used to count the number of items in
the 'global_auth_tok_list' list. This variable is not needed because there
are no checks based upon it.
Signed-off-by: NRoberto Sassu <roberto.sassu@polito.it>
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Change the write path to encrypt the data only when the page is written to
disk in ecryptfs_writepage. Previously, ecryptfs encrypts the page in
ecryptfs_write_end which means that if there are multiple write requests to
the same page, ecryptfs ends up re-encrypting that page over and over again.
This patch minimizes the number of encryptions needed.
Signed-off-by: NThieu Le <thieule@chromium.org>
[tyhicks: Changed NULL .drop_inode sop pointer to generic_drop_inode]
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Now that grow_file() is not called in the ecryptfs_create() path, the
ECRYPTFS_NEW_FILE flag is no longer needed. It helped
ecryptfs_readpage() know not to decrypt zeroes that were read from the
lower file in the grow_file() path.
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Allow for NULL nameidata pointers in eCryptfs create, lookup, and
d_revalidate functions.
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Add __attribute__((format... to __ecryptfs_printk
Make formats and arguments match.
Add casts to (unsigned long long) for %llu.
Signed-off-by: NJoe Perches <joe@perches.com>
[tyhicks: 80 columns cleanup and fixed typo]
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

The definition of ECRYPTFS_SUPER_MAGIC has been moved to the include
file 'linux/magic.h' to become available to other kernel subsystems.
Signed-off-by: NRoberto Sassu <roberto.sassu@polito.it>
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

This patch adds a new mount parameter 'ecryptfs_mount_auth_tok_only' to
force ecryptfs to use only authentication tokens which signature has
been specified at mount time with parameters 'ecryptfs_sig' and
'ecryptfs_fnek_sig'. In this way, after disabling the passthrough and
the encrypted view modes, it's possible to make available to users only
files encrypted with the specified authentication token.
Signed-off-by: NRoberto Sassu <roberto.sassu@polito.it>
Cc: Dustin Kirkland <kirkland@canonical.com>
Cc: James Morris <jmorris@namei.org>
[Tyler: Clean up coding style errors found by checkpatch]
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJiri Kosina <jkosina@suse.cz>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

This ensures that dirty data gets flushed properly.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

The ecryptfs_encrypted_view mount option provides a unified way of
viewing encrypted eCryptfs files.  If the metadata is stored in a xattr,
the metadata is moved to the file header when the file is read inside
the eCryptfs mount.  Because of this, we should strip the
ECRYPTFS_METADATA_IN_XATTR flag from the header's flag section.  This
allows eCryptfs to treat the file as an eCryptfs file with a header
at the front.
Reviewed-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

This patch renames the num_header_bytes_at_front variable to
metadata_size since it now contains the max size of the metadata.
Reviewed-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Fixes regression in 8faece5f

When using the ecryptfs_xattr_metadata mount option, eCryptfs stores the
metadata (normally stored at the front of the file) in the user.ecryptfs
xattr.  This causes ecryptfs_crypt_stat.num_header_bytes_at_front to be
0, since there is no header data at the front of the file.  This results
in too much memory being requested and ENOMEM being returned from
ecryptfs_write_metadata().

This patch fixes the problem by using the num_header_bytes_at_front
variable for specifying the max size of the metadata, despite whether it
is stored in the header or xattr.
Reviewed-by: NEric Sandeen <sandeen@redhat.com>
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

A feature was added to the eCryptfs umount helper to automatically
unlink the keys used for an eCryptfs mount from the kernel keyring upon
umount.  This patch keeps the unrecognized mount option warnings for
ecryptfs_unlink_sigs out of the logs.
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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: NTyler Hicks <tyhicks@linux.vnet.ibm.com>
Acked-by: NDustin Kirkland <kirkland@canonical.com>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>