The patch 237fead6: "[PATCH] ecryptfs: fs/Makefile and
fs/Kconfig" from Oct 4, 2006, leads to the following static checker
warning:

  fs/ecryptfs/crypto.c:846 ecryptfs_new_file_context()
  error: off-by-one overflow 'crypt_stat->cipher' size 32.  rl = '0-32'

There is a mismatch between the size of ecryptfs_crypt_stat.cipher
and ecryptfs_mount_crypt_stat.global_default_cipher_name causing the
copy of the cipher name to cause a off-by-one string copy error. This
fix ensures the space reserved for this string is the same size including
the trailing zero at the end throughout ecryptfs.

This fix avoids increasing the size of ecryptfs_crypt_stat.cipher
and also ecryptfs_parse_tag_70_packet_silly_stack.cipher_string and instead
reduces the of ECRYPTFS_MAX_CIPHER_NAME_SIZE to 31 and includes the + 1 for
the end of string terminator.

NOTE: An overflow is not possible in practice since the value copied
into global_default_cipher_name is validated by
ecryptfs_code_for_cipher_string() at mount time. None of the allowed
cipher strings are long enough to cause the potential buffer overflow
fixed by this patch.
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
[tyhicks: Added the NOTE about the overflow not being triggerable]
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>

Since "BDI: Provide backing device capability information [try #3]" the
backing_dev_info structure also provides flags for the kind of mmap
operation available in a nommu environment, which is entirely unrelated
to it's original purpose.

Introduce a new nommu-only file operation to provide this information to
the nommu mmap code instead.  Splitting this from the backing_dev_info
structure allows to remove lots of backing_dev_info instance that aren't
otherwise needed, and entirely gets rid of the concept of providing a
backing_dev_info for a character device.  It also removes the need for
the mtd_inodefs filesystem.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NTejun Heo <tj@kernel.org>
Acked-by: NBrian Norris <computersforpeace@gmail.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

Add a simple read-only counter to super_block that indicates how deep this
is in the stack of filesystems.  Previously ecryptfs was the only stackable
filesystem and it explicitly disallowed multiple layers of itself.

Overlayfs, however, can be stacked recursively and also may be stacked
on top of ecryptfs or vice versa.

To limit the kernel stack usage we must limit the depth of the
filesystem stack.  Initially the limit is set to 2.
Signed-off-by: NMiklos Szeredi <mszeredi@suse.cz>

The ecryptfs_encrypted_view mount option greatly changes the
functionality of an eCryptfs mount. Instead of encrypting and decrypting
lower files, it provides a unified view of the encrypted files in the
lower filesystem. The presence of the ecryptfs_encrypted_view mount
option is intended to force a read-only mount and modifying files is not
supported when the feature is in use. See the following commit for more
information:

  e77a56dd [PATCH] eCryptfs: Encrypted passthrough

This patch forces the mount to be read-only when the
ecryptfs_encrypted_view mount option is specified by setting the
MS_RDONLY flag on the superblock. Additionally, this patch removes some
broken logic in ecryptfs_open() that attempted to prevent modifications
of files when the encrypted view feature was in use. The check in
ecryptfs_open() was not sufficient to prevent file modifications using
system calls that do not operate on a file descriptor.
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Reported-by: NPriya Bansal <p.bansal@samsung.com>
Cc: stable@vger.kernel.org # v2.6.21+: e77a56dd [PATCH] eCryptfs: Encrypted passthrough

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

There are two places in ecryptfs that benefit from using
ecryptfs_dentry_to_lower_path() instead of separate calls to
ecryptfs_dentry_to_lower() and ecryptfs_dentry_to_lower_mnt().  Both
sites use fewer instructions and less stack (determined by examining
objdump output).
Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>

Modify the request_module to prefix the file system type with "fs-"
and add aliases to all of the filesystems that can be built as modules
to match.

A common practice is to build all of the kernel code and leave code
that is not commonly needed as modules, with the result that many
users are exposed to any bug anywhere in the kernel.

Looking for filesystems with a fs- prefix limits the pool of possible
modules that can be loaded by mount to just filesystems trivially
making things safer with no real cost.

Using aliases means user space can control the policy of which
filesystem modules are auto-loaded by editing /etc/modprobe.d/*.conf
with blacklist and alias directives.  Allowing simple, safe,
well understood work-arounds to known problematic software.

This also addresses a rare but unfortunate problem where the filesystem
name is not the same as it's module name and module auto-loading
would not work.  While writing this patch I saw a handful of such
cases.  The most significant being autofs that lives in the module
autofs4.

This is relevant to user namespaces because we can reach the request
module in get_fs_type() without having any special permissions, and
people get uncomfortable when a user specified string (in this case
the filesystem type) goes all of the way to request_module.

After having looked at this issue I don't think there is any
particular reason to perform any filtering or permission checks beyond
making it clear in the module request that we want a filesystem
module.  The common pattern in the kernel is to call request_module()
without regards to the users permissions.  In general all a filesystem
module does once loaded is call register_filesystem() and go to sleep.
Which means there is not much attack surface exposed by loading a
filesytem module unless the filesystem is mounted.  In a user
namespace filesystems are not mounted unless .fs_flags = FS_USERNS_MOUNT,
which most filesystems do not set today.
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Acked-by: NKees Cook <keescook@chromium.org>
Reported-by: NKees Cook <keescook@google.com>
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>

There's no reason to call rcu_barrier() on every
deactivate_locked_super().  We only need to make sure that all delayed rcu
free inodes are flushed before we destroy related cache.

Removing rcu_barrier() from deactivate_locked_super() affects some fast
paths.  E.g.  on my machine exit_group() of a last process in IPC
namespace takes 0.07538s.  rcu_barrier() takes 0.05188s of that time.
Signed-off-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Acked-by: NSerge Hallyn <serge.hallyn@canonical.com>
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>

Fixes a regression caused by:

821f7494 eCryptfs: Revert to a writethrough cache model

That patch reverted some code (specifically, 32001d6f) that was
necessary to properly handle open() -> mmap() -> close() -> dirty pages
-> munmap(), because the lower file could be closed before the dirty
pages are written out.

Rather than reapplying 32001d6f, this approach is a better way of
ensuring that the lower file is still open in order to handle writing
out the dirty pages. It is called from ecryptfs_release(), while we have
a lock on the lower file pointer, just before the lower file gets the
final fput() and we overwrite the pointer.

https://launchpad.net/bugs/1047261Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Reported-by: NArtemy Tregubenko <me@arty.name>
Tested-by: NArtemy Tregubenko <me@arty.name>
Tested-by: NColin Ian King <colin.king@canonical.com>

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

Pass mount flags to sget() so that it can use them in initialising a new
superblock before the set function is called.  They could also be passed to the
compare function.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

The issue occurs when eCryptfs is mounted with a cipher supported by
the crypto subsystem but not by eCryptfs. The mount succeeds and an
error does not occur until a write. This change checks for eCryptfs
cipher support at mount time.

Resolves Launchpad issue #338914, reported by Tyler Hicks in 03/2009.
https://bugs.launchpad.net/ecryptfs/+bug/338914Signed-off-by: NTim Sally <tsally@atomicpeace.com>
Signed-off-by: NTyler Hicks <tyhicks@canonical.com>

When the eCryptfs mount options do not include '-o acl', but the lower
filesystem's mount options do include 'acl', the MS_POSIXACL flag is not
flipped on in the eCryptfs super block flags. This flag is what the VFS
checks in do_last() when deciding if the current umask should be applied
to a newly created inode's mode or not. When a default POSIX ACL mask is
set on a directory, the current umask is incorrectly applied to new
inodes created in the directory. This patch ignores the MS_POSIXACL flag
passed into ecryptfs_mount() and sets the flag on the eCryptfs super
block depending on the flag's presence on the lower super block.

Additionally, it is incorrect to allow a writeable eCryptfs mount on top
of a read-only lower mount. This missing check did not allow writes to
the read-only lower mount because permissions checks are still performed
on the lower filesystem's objects but it is best to simply not allow a
rw mount on top of ro mount. However, a ro eCryptfs mount on top of a rw
mount is valid and still allowed.

https://launchpad.net/bugs/1009207Signed-off-by: NTyler Hicks <tyhicks@canonical.com>
Reported-by: NStefan Beller <stefanbeller@googlemail.com>
Cc: John Johansen <john.johansen@canonical.com>

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

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

Close a TOCTOU race for mounts done via ecryptfs-mount-private.  The mount
source (device) can be raced when the ownership test is done in userspace.
Provide Ecryptfs a means to force the uid check at mount time.
Signed-off-by: NJohn Johansen <john.johansen@canonical.com>
Cc: <stable@kernel.org>
Signed-off-by: NTyler Hicks <tyhicks@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>

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>

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>

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>

Fixes generated by 'codespell' and manually reviewed.
Signed-off-by: NLucas De Marchi <lucas.demarchi@profusion.mobi>

A requested key is write locked in order to prevent modifications on the
authentication token while it is being used.
Signed-off-by: NRoberto Sassu <roberto.sassu@polito.it>
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>

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>

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>

This patch initializes the 'magic' field of ecryptfs filesystems to
ECRYPTFS_SUPER_MAGIC.
Signed-off-by: NRoberto Sassu <roberto.sassu@polito.it>
[tyhicks: merge with 66cb7666]
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>

Stephen Rothwell reports that the vfs merge broke the build of ecryptfs.
The breakage comes from commit 66cb7666 ("sanitize ecryptfs
->mount()") which was obviously not even build tested. Tssk, tssk, Al.

This is the minimal build fixup for the situation, although I don't have
a filesystem to actually test it with.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

kill ecryptfs_read_super(), reorder code allowing to use
normal d_alloc_root() instead of opencoding it.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Reduce some branches and memory accesses in dcache lookup by adding dentry
flags to indicate common d_ops are set, rather than having to check them.
This saves a pointer memory access (dentry->d_op) in common path lookup
situations, and saves another pointer load and branch in cases where we
have d_op but not the particular operation.

Patched with:

git grep -E '[.>]([[:space:]])*d_op([[:space:]])*=' | xargs sed -e 's/\([^\t ]*\)->d_op = \(.*\);/d_set_d_op(\1, \2);/' -e 's/\([^\t ]*\)\.d_op = \(.*\);/d_set_d_op(\&\1, \2);/' -i
Signed-off-by: NNick Piggin <npiggin@kernel.dk>

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: NAl Viro <viro@zeniv.linux.org.uk>

The BKL is only used in fill_super, which is protected by the superblocks
s_umount rw_semaphorei, and in fasync, which does not do anything that
could require the BKL. Therefore it is safe to remove the BKL entirely.
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Dustin Kirkland <kirkland@canonical.com>
Cc: Tyler Hicks <tyhicks@linux.vnet.ibm.com>
Cc: ecryptfs-devel@lists.launchpad.net

This patch is a preparation necessary to remove the BKL from do_new_mount().
It explicitly adds calls to lock_kernel()/unlock_kernel() around
get_sb/fill_super operations for filesystems that still uses the BKL.

I've read through all the code formerly covered by the BKL inside
do_kern_mount() and have satisfied myself that it doesn't need the BKL
any more.

do_kern_mount() is already called without the BKL when mounting the rootfs
and in nfsctl. do_kern_mount() calls vfs_kern_mount(), which is called
from various places without BKL: simple_pin_fs(), nfs_do_clone_mount()
through nfs_follow_mountpoint(), afs_mntpt_do_automount() through
afs_mntpt_follow_link(). Both later functions are actually the filesystems
follow_link inode operation. vfs_kern_mount() is calling the specified
get_sb function and lets the filesystem do its job by calling the given
fill_super function.

Therefore I think it is safe to push down the BKL from the VFS to the
low-level filesystems get_sb/fill_super operation.

[arnd: do not add the BKL to those file systems that already
       don't use it elsewhere]
Signed-off-by: NJan Blunck <jblunck@infradead.org>
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Cc: Matthew Wilcox <matthew@wil.cx>
Cc: Christoph Hellwig <hch@infradead.org>

This is a seriously simplified patch from Eric Sandeen; copy of
rationale follows:
===
  mounting stacked ecryptfs on ecryptfs has been shown to lead to bugs
  in testing.  For crypto info in xattr, there is no mechanism for handling
  this at all, and for normal file headers, we run into other trouble:

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
  IP: [<ffffffffa015b0b3>] ecryptfs_d_revalidate+0x43/0xa0 [ecryptfs]
  ...

  There doesn't seem to be any good usecase for this, so I'd suggest just
  disallowing the configuration.

  Based on a patch originally, I believe, from Mike Halcrow.
===
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

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

First of all, get_sb_nodev() grabs anon dev minor and we
never free it in ecryptfs ->kill_sb().  Moreover, on one
of the failure exits in ecryptfs_get_sb() we leak things -
it happens before we set ->s_root and ->put_super() won't
be called in that case.  Solution: kill ->put_super(), do
all that stuff in ->kill_sb().  And use kill_anon_sb() instead
of generic_shutdown_super() to deal with anon dev leak.
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>

include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h

percpu.h is included by sched.h and module.h and thus ends up being
included when building most .c files.  percpu.h includes slab.h which
in turn includes gfp.h making everything defined by the two files
universally available and complicating inclusion dependencies.

percpu.h -> slab.h dependency is about to be removed.  Prepare for
this change by updating users of gfp and slab facilities include those
headers directly instead of assuming availability.  As this conversion
needs to touch large number of source files, the following script is
used as the basis of conversion.

  http://userweb.kernel.org/~tj/misc/slabh-sweep.py

The script does the followings.

* Scan files for gfp and slab usages and update includes such that
  only the necessary includes are there.  ie. if only gfp is used,
  gfp.h, if slab is used, slab.h.

* When the script inserts a new include, it looks at the include
  blocks and try to put the new include such that its order conforms
  to its surrounding.  It's put in the include block which contains
  core kernel includes, in the same order that the rest are ordered -
  alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
  doesn't seem to be any matching order.

* If the script can't find a place to put a new include (mostly
  because the file doesn't have fitting include block), it prints out
  an error message indicating which .h file needs to be added to the
  file.

The conversion was done in the following steps.

1. The initial automatic conversion of all .c files updated slightly
   over 4000 files, deleting around 700 includes and adding ~480 gfp.h
   and ~3000 slab.h inclusions.  The script emitted errors for ~400
   files.

2. Each error was manually checked.  Some didn't need the inclusion,
   some needed manual addition while adding it to implementation .h or
   embedding .c file was more appropriate for others.  This step added
   inclusions to around 150 files.

3. The script was run again and the output was compared to the edits
   from #2 to make sure no file was left behind.

4. Several build tests were done and a couple of problems were fixed.
   e.g. lib/decompress_*.c used malloc/free() wrappers around slab
   APIs requiring slab.h to be added manually.

5. The script was run on all .h files but without automatically
   editing them as sprinkling gfp.h and slab.h inclusions around .h
   files could easily lead to inclusion dependency hell.  Most gfp.h
   inclusion directives were ignored as stuff from gfp.h was usually
   wildly available and often used in preprocessor macros.  Each
   slab.h inclusion directive was examined and added manually as
   necessary.

6. percpu.h was updated not to include slab.h.

7. Build test were done on the following configurations and failures
   were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
   distributed build env didn't work with gcov compiles) and a few
   more options had to be turned off depending on archs to make things
   build (like ipr on powerpc/64 which failed due to missing writeq).

   * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
   * powerpc and powerpc64 SMP allmodconfig
   * sparc and sparc64 SMP allmodconfig
   * ia64 SMP allmodconfig
   * s390 SMP allmodconfig
   * alpha SMP allmodconfig
   * um on x86_64 SMP allmodconfig

8. percpu.h modifications were reverted so that it could be applied as
   a separate patch and serve as bisection point.

Given the fact that I had only a couple of failures from tests on step
6, I'm fairly confident about the coverage of this conversion patch.
If there is a breakage, it's likely to be something in one of the arch
headers which should be easily discoverable easily on most builds of
the specific arch.
Signed-off-by: NTejun Heo <tj@kernel.org>
Guess-its-ok-by: NChristoph Lameter <cl@linux-foundation.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>

Signed-off-by: NErez Zadok <ezk@cs.sunysb.edu>
Acked-by: NDustin Kirkland <kirkland@canonical.com>
Signed-off-by: NTyler Hicks <tyhicks@linux.vnet.ibm.com>