Reclaim will be leaving shadow entries in the page cache radix tree upon
evicting the real page. As those pages are found from the LRU, an
iput() can lead to the inode being freed concurrently. At this point,
reclaim must no longer install shadow pages because the inode freeing
code needs to ensure the page tree is really empty.
Add an address_space flag, AS_EXITING, that the inode freeing code sets
under the tree lock before doing the final truncate. Reclaim will check
for this flag before installing shadow pages.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Minchan Kim <minchan@kernel.org>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bob Liu <bob.liu@oracle.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jan Kara <jack@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Luigi Semenzato <semenzato@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Metin Doslu <metin@citusdata.com>
Cc: Michel Lespinasse <walken@google.com>
Cc: Ozgun Erdogan <ozgun@citusdata.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Roman Gushchin <klamm@yandex-team.ru>
Cc: Ryan Mallon <rmallon@gmail.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If ecryptfs_readlink_lower() fails, buf remains an uninitialized
pointer and passing it nd_set_link() won't do anything good.
Fixed by switching ecryptfs_readlink_lower() to saner API - make it
return buf or ERR_PTR(...) and update callers.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Use this new function to make code more comprehensible, since we are
reinitialzing the completion, not initializing.
[akpm@linux-foundation.org: linux-next resyncs]
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Acked-by: Linus Walleij <linus.walleij@linaro.org> (personally at LCE13)
Cc: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When accessing the lower_file pointer located in private_data of
eCryptfs files, there is no need to check to see if the private_data
pointer has been initialized to a non-NULL value. The file->private_data
and file->private_data->lower_file pointers are always initialized to
non-NULL values in ecryptfs_open().
This change quiets a Smatch warning:
CHECK /var/scm/kernel/linux/fs/ecryptfs/file.c
fs/ecryptfs/file.c:321 ecryptfs_unlocked_ioctl() error: potential NULL dereference 'lower_file'.
fs/ecryptfs/file.c:335 ecryptfs_compat_ioctl() error: potential NULL dereference 'lower_file'.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: Geyslan G. Bem <geyslan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Pull vfs updates from Al Viro:
"All kinds of stuff this time around; some more notable parts:
- RCU'd vfsmounts handling
- new primitives for coredump handling
- files_lock is gone
- Bruce's delegations handling series
- exportfs fixes
plus misc stuff all over the place"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (101 commits)
ecryptfs: ->f_op is never NULL
locks: break delegations on any attribute modification
locks: break delegations on link
locks: break delegations on rename
locks: helper functions for delegation breaking
locks: break delegations on unlink
namei: minor vfs_unlink cleanup
locks: implement delegations
locks: introduce new FL_DELEG lock flag
vfs: take i_mutex on renamed file
vfs: rename I_MUTEX_QUOTA now that it's not used for quotas
vfs: don't use PARENT/CHILD lock classes for non-directories
vfs: pull ext4's double-i_mutex-locking into common code
exportfs: fix quadratic behavior in filehandle lookup
exportfs: better variable name
exportfs: move most of reconnect_path to helper function
exportfs: eliminate unused "noprogress" counter
exportfs: stop retrying once we race with rename/remove
exportfs: clear DISCONNECTED on all parents sooner
exportfs: more detailed comment for path_reconnect
...
NFSv4 uses leases to guarantee that clients can cache metadata as well
as data.
Cc: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz>
Cc: David Howells <dhowells@redhat.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
We need to break delegations on any operation that changes the set of
links pointing to an inode. Start with unlink.
Such operations also hold the i_mutex on a parent directory. Breaking a
delegation may require waiting for a timeout (by default 90 seconds) in
the case of a unresponsive NFS client. To avoid blocking all directory
operations, we therefore drop locks before waiting for the delegation.
The logic then looks like:
acquire locks
...
test for delegation; if found:
take reference on inode
release locks
wait for delegation break
drop reference on inode
retry
It is possible this could never terminate. (Even if we take precautions
to prevent another delegation being acquired on the same inode, we could
get a different inode on each retry.) But this seems very unlikely.
The initial test for a delegation happens after the lock on the target
inode is acquired, but the directory inode may have been acquired
further up the call stack. We therefore add a "struct inode **"
argument to any intervening functions, which we use to pass the inode
back up to the caller in the case it needs a delegation synchronously
broken.
Cc: David Howells <dhowells@redhat.com>
Cc: Tyler Hicks <tyhicks@canonical.com>
Cc: Dustin Kirkland <dustin.kirkland@gazzang.com>
Acked-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
If the underlying dentry doesn't have ->d_revalidate(), there's no need to
force dropping out of RCU mode. All we need for that is to make freeing
ecryptfs_dentry_info RCU-delayed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Shifting page->index on 32 bit systems was overflowing, causing
data corruption of > 4GB files. Fix this by casting it first.
https://launchpad.net/bugs/1243636
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Reported-by: Lars Duesing <lars.duesing@camelotsweb.de>
Cc: stable@vger.kernel.org # v3.11+
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
In 'decrypt_pki_encrypted_session_key' function:
Initializes 'payload' pointer and releases it on exit.
Signed-off-by: Geyslan G. Bem <geyslan@gmail.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Cc: stable@vger.kernel.org # v2.6.28+
It might be possible for two callers to race the mutex lock after the
NULL ctx check. Instead, move the lock above the check so there isn't
the possibility of leaking a crypto ctx. Additionally, report the full
algo name when failing.
Signed-off-by: Kees Cook <keescook@chromium.org>
[tyhicks: remove out label, which is no longer used]
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
It doesn't make sense to check if an array is NULL. The compiler just
removes the check.
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
- Remove redundant code by merging some encrypt and decrypt functions
- Get rid of a helper page allocation during page decryption by using in-place
decryption
- Better use of entire pages during page crypto operations
- Several code cleanups
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Merge tag 'ecryptfs-3.11-rc1-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs
Pull eCryptfs updates from Tyler Hicks:
"Code cleanups and improved buffer handling during page crypto
operations:
- Remove redundant code by merging some encrypt and decrypt functions
- Get rid of a helper page allocation during page decryption by using
in-place decryption
- Better use of entire pages during page crypto operations
- Several code cleanups"
* tag 'ecryptfs-3.11-rc1-cleanup' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
Use ecryptfs_dentry_to_lower_path in a couple of places
eCryptfs: Make extent and scatterlist crypt function parameters similar
eCryptfs: Collapse crypt_page_offset() into crypt_extent()
eCryptfs: Merge ecryptfs_encrypt_extent() and ecryptfs_decrypt_extent()
eCryptfs: Combine page_offset crypto functions
eCryptfs: Combine encrypt_scatterlist() and decrypt_scatterlist()
eCryptfs: Decrypt pages in-place
eCryptfs: Accept one offset parameter in page offset crypto functions
eCryptfs: Simplify lower file offset calculation
eCryptfs: Read/write entire page during page IO
eCryptfs: Use entire helper page during page crypto operations
eCryptfs: Cocci spatch "memdup.spatch"
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: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
iterate_dir(): new helper, replacing vfs_readdir().
struct dir_context: contains the readdir callback (and will get more stuff
in it), embedded into whatever data that callback wants to deal with;
eventually, we'll be passing it to ->readdir() replacement instead of
(data,filldir) pair.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The 'dest' abbreviation is only used in crypt_scatterlist(), while all
other functions in crypto.c use 'dst' so dest_sg should be renamed to
dst_sg.
The crypt_stat parameter is typically the first parameter in internal
eCryptfs functions so crypt_stat and dst_page should be swapped in
crypt_extent().
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
crypt_page_offset() simply initialized the two scatterlists and called
crypt_scatterlist() so it is simple enough to move into the only
function that calls it.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
They are identical except if the src_page or dst_page index is used, so
they can be merged safely if page_index is conditionally assigned.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Combine ecryptfs_encrypt_page_offset() and
ecryptfs_decrypt_page_offset(). These two functions are functionally
identical so they can be safely merged if the caller can indicate
whether an encryption or decryption operation should occur.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
These two functions are identical except for a debug printk and whether
they call crypto_ablkcipher_encrypt() or crypto_ablkcipher_decrypt(), so
they can be safely merged if the caller can indicate if encryption or
decryption should occur.
The debug printk is useless so it is removed.
Two new #define's are created to indicate if an ENCRYPT or DECRYPT
operation is desired.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
When reading in a page, eCryptfs would allocate a helper page, fill it
with encrypted data from the lower filesytem, and then decrypt the data
from the encrypted page and store the result in the eCryptfs page cache
page.
The crypto API supports in-place crypto operations which means that the
allocation of the helper page is unnecessary when decrypting. This patch
gets rid of the unneeded page allocation by reading encrypted data from
the lower filesystem directly into the page cache page. The page cache
page is then decrypted in-place.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
There is no longer a need to accept different offset values for the
source and destination pages when encrypting/decrypting an extent in an
eCryptfs page. The two offsets can be collapsed into a single parameter.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Now that lower filesystem IO operations occur for complete
PAGE_CACHE_SIZE bytes, the calculation for converting an eCryptfs extent
index into a lower file offset can be simplified.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
When reading and writing encrypted pages, perform IO using the entire
page all at once rather than 4096 bytes at a time.
This only affects architectures where PAGE_CACHE_SIZE is larger than
4096 bytes.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
When encrypting eCryptfs pages and decrypting pages from the lower
filesystem, utilize the entire helper page rather than only the first
4096 bytes.
This only affects architectures where PAGE_CACHE_SIZE is larger than
4096 bytes.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Error out of ecryptfs_fsync() if filemap_write_and_wait() fails.
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Cc: Paul Taysom <taysom@chromium.org>
Cc: Olof Johansson <olofj@chromium.org>
Cc: stable@vger.kernel.org # v3.6+
When msync is called on a memory mapped file, that
data is not flushed to the disk.
In Linux, msync calls fsync for the file. For ecryptfs,
fsync just calls the lower level file system's fsync.
Changed the ecryptfs fsync code to call filemap_write_and_wait
before calling the lower level fsync.
Addresses the problem described in http://crbug.com/239536
Signed-off-by: Paul Taysom <taysom@chromium.org>
Signed-off-by: Tyler Hicks <tyhicks@canonical.com>
Cc: stable@vger.kernel.org # v3.6+
available by moving to the ablkcipher crypto API. The improvement is more
apparent on faster storage devices. There's no noticeable change when hardware
crypto is not available.
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Merge tag 'ecryptfs-3.10-rc1-ablkcipher' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs
Pull eCryptfs update from Tyler Hicks:
"Improve performance when AES-NI (and most likely other crypto
accelerators) is available by moving to the ablkcipher crypto API.
The improvement is more apparent on faster storage devices.
There's no noticeable change when hardware crypto is not available"
* tag 'ecryptfs-3.10-rc1-ablkcipher' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
eCryptfs: Use the ablkcipher crypto API
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: Tyler Hicks <tyhicks@canonical.com>
Acked-by: Colin King <colin.king@canonical.com>
Reviewed-by: Zeev 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>
Pull more vfs fixes from Al Viro:
"Regression fix from Geert + yet another open-coded kernel_read()"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
ecryptfs: don't open-code kernel_read()
xtensa simdisk: Fix proc_create_data() conversion fallout
Pull namespace bugfixes from Eric Biederman:
"This is three simple fixes against 3.9-rc1. I have tested each of
these fixes and verified they work correctly.
The userns oops in key_change_session_keyring and the BUG_ON triggered
by proc_ns_follow_link were found by Dave Jones.
I am including the enhancement for mount to only trigger requests of
filesystem modules here instead of delaying this for the 3.10 merge
window because it is both trivial and the kind of change that tends to
bit-rot if left untouched for two months."
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/ebiederm/user-namespace:
proc: Use nd_jump_link in proc_ns_follow_link
fs: Limit sys_mount to only request filesystem modules (Part 2).
fs: Limit sys_mount to only request filesystem modules.
userns: Stop oopsing in key_change_session_keyring
The code cleanups fix up W=1 compiler warnings and some unnecessary checks. The
new Kconfig option, defaulting to N, allows the rarely used eCryptfs kernel to
userspace communication channel to be compiled out. This may be the first step
in it being eventually removed.
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Merge tag 'ecryptfs-3.9-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs
Pull ecryptfs fixes from Tyler Hicks:
"Minor code cleanups and new Kconfig option to disable /dev/ecryptfs
The code cleanups fix up W=1 compiler warnings and some unnecessary
checks. The new Kconfig option, defaulting to N, allows the rarely
used eCryptfs kernel to userspace communication channel to be compiled
out. This may be the first step in it being eventually removed."
Hmm. I'm not sure whether these should be called "fixes", and it
probably should have gone in the merge window. But I'll let it slide.
* tag 'ecryptfs-3.9-rc2-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tyhicks/ecryptfs:
eCryptfs: allow userspace messaging to be disabled
eCryptfs: Fix redundant error check on ecryptfs_find_daemon_by_euid()
ecryptfs: ecryptfs_msg_ctx_alloc_to_free(): remove kfree() redundant null check
eCryptfs: decrypt_pki_encrypted_session_key(): remove kfree() redundant null check
eCryptfs: remove unneeded checks in virt_to_scatterlist()
eCryptfs: Fix -Wmissing-prototypes warnings
eCryptfs: Fix -Wunused-but-set-variable warnings
eCryptfs: initialize payload_len in keystore.c
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: Kees Cook <keescook@chromium.org>
Signed-off-by: Tyler 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: Serge Hallyn <serge.hallyn@canonical.com>
Acked-by: Kees Cook <keescook@chromium.org>
Reported-by: Kees Cook <keescook@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
