linux-toradex.git/fs/ecryptfs/inode.c, branch v3.4.73

eCryptfs: Revert to a writethrough cache model

2012-10-21T16:28:01+00:00

commit 821f7494a77627fb1ab539591c57b22cdca702d6 upstream.

A change was made about a year ago to get eCryptfs to better utilize its
page cache during writes. The idea was to do the page encryption
operations during page writeback, rather than doing them when initially
writing into the page cache, to reduce the number of page encryption
operations during sequential writes. This meant that the encrypted page
would only be written to the lower filesystem during page writeback,
which was a change from how eCryptfs had previously wrote to the lower
filesystem in ecryptfs_write_end().

The change caused a few eCryptfs-internal bugs that were shook out.
Unfortunately, more grave side effects have been identified that will
force changes outside of eCryptfs. Because the lower filesystem isn't
consulted until page writeback, eCryptfs has no way to pass lower write
errors (ENOSPC, mainly) back to userspace. Additionaly, it was reported
that quotas could be bypassed because of the way eCryptfs may sometimes
open the lower filesystem using a privileged kthread.

It would be nice to resolve the latest issues, but it is best if the
eCryptfs commits be reverted to the old behavior in the meantime.

This reverts:
32001d6f "eCryptfs: Flush file in vma close"
5be79de2 "eCryptfs: Flush dirty pages in setattr"
57db4e8d "ecryptfs: modify write path to encrypt page in writepage"

Signed-off-by: Tyler Hicks 
Tested-by: Colin King 
Cc: Colin King 
Cc: Thieu Le 
Cc: Jonathan Nieder 
Signed-off-by: Greg Kroah-Hartman

eCryptfs: Initialize empty lower files when opening them

2012-10-21T16:28:01+00:00

commit e3ccaa9761200952cc269b1f4b7d7bb77a5e071b upstream.

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/911507

Signed-off-by: Tyler Hicks 
Cc: John Johansen 
Cc: Colin Ian King 
Cc: Jonathan Nieder 
Signed-off-by: Greg Kroah-Hartman

eCryptfs: Unlink lower inode when ecryptfs_create() fails

2012-10-21T16:28:01+00:00

commit 8bc2d3cf612994a960c2e8eaea37f6676f67082a upstream.

ecryptfs_create() creates a lower inode, allocates an eCryptfs inode,
initializes the eCryptfs inode and cryptographic metadata attached to
the inode, and then writes the metadata to the header of the file.

If an error was to occur after the lower inode was created, an empty
lower file would be left in the lower filesystem. This is a problem
because ecryptfs_open() refuses to open any lower files which do not
have the appropriate metadata in the file header.

This patch properly unlinks the lower inode when an error occurs in the
later stages of ecryptfs_create(), reducing the chance that an empty
lower file will be left in the lower filesystem.

https://launchpad.net/bugs/872905

Signed-off-by: Tyler Hicks 
Cc: John Johansen 
Cc: Colin Ian King 
Cc: Jonathan Nieder 
Signed-off-by: Greg Kroah-Hartman

eCryptfs: Copy up attributes of the lower target inode after rename

2012-10-02T17:29:51+00:00

commit 8335eafc2859e1a26282bef7c3d19f3d68868b8a upstream.

After calling into the lower filesystem to do a rename, the lower target
inode's attributes were not copied up to the eCryptfs target inode. This
resulted in the eCryptfs target inode staying around, rather than being
evicted, because i_nlink was not updated for the eCryptfs inode. This
also meant that eCryptfs didn't do the final iput() on the lower target
inode so it stayed around, as well. This would result in a failure to
free up space occupied by the target file in the rename() operation.
Both target inodes would eventually be evicted when the eCryptfs
filesystem was unmounted.

This patch calls fsstack_copy_attr_all() after the lower filesystem
does its ->rename() so that important inode attributes, such as i_nlink,
are updated at the eCryptfs layer. ecryptfs_evict_inode() is now called
and eCryptfs can drop its final reference on the lower inode.

http://launchpad.net/bugs/561129

Signed-off-by: Tyler Hicks 
Tested-by: Colin Ian King 
Signed-off-by: Greg Kroah-Hartman

eCryptfs: Copy up lower inode attrs after setting lower xattr

2012-02-16T22:06:27+00:00

After passing through a ->setxattr() call, eCryptfs needs to copy the
inode attributes from the lower inode to the eCryptfs inode, as they
may have changed in the lower filesystem's ->setxattr() path.

One example is if an extended attribute containing a POSIX Access
Control List is being set. The new ACL may cause the lower filesystem to
modify the mode of the lower inode and the eCryptfs inode would need to
be updated to reflect the new mode.

https://launchpad.net/bugs/926292

Signed-off-by: Tyler Hicks 
Reported-by: Sebastien Bacher 
Cc: John Johansen 
Cc:

eCryptfs: Check inode changes in setattr

2012-01-25T20:43:41+00:00

Most filesystems call inode_change_ok() very early in ->setattr(), but
eCryptfs didn't call it at all. It allowed the lower filesystem to make
the call in its ->setattr() function. Then, eCryptfs would copy the
appropriate inode attributes from the lower inode to the eCryptfs inode.

This patch changes that and actually calls inode_change_ok() on the
eCryptfs inode, fairly early in ecryptfs_setattr(). Ideally, the call
would happen earlier in ecryptfs_setattr(), but there are some possible
inode initialization steps that must happen first.

Since the call was already being made on the lower inode, the change in
functionality should be minimal, except for the case of a file extending
truncate call. In that case, inode_newsize_ok() was never being
called on the eCryptfs inode. Rather than inode_newsize_ok() catching
maximum file size errors early on, eCryptfs would encrypt zeroed pages
and write them to the lower filesystem until the lower filesystem's
write path caught the error in generic_write_checks(). This patch
introduces a new function, called ecryptfs_inode_newsize_ok(), which
checks if the new lower file size is within the appropriate limits when
the truncate operation will be growing the lower file.

In summary this change prevents eCryptfs truncate operations (and the
resulting page encryptions), which would exceed the lower filesystem
limits or FSIZE rlimits, from ever starting.

Signed-off-by: Tyler Hicks 
Reviewed-by: Li Wang 
Cc:

fs: propagate umode_t, misc bits

2012-01-04T03:55:10+00:00

Signed-off-by: Al Viro

kill ecryptfs_create_underlying_file()

2012-01-04T03:54:57+00:00

it's a just a wrapper for vfs_create()

Signed-off-by: Al Viro

switch ->mknod() to umode_t

2012-01-04T03:54:54+00:00

Signed-off-by: Al Viro

switch ->create() to umode_t

2012-01-04T03:54:53+00:00

vfs_create() ignores everything outside of 16bit subset of its
mode argument; switching it to umode_t is obviously equivalent
and it's the only caller of the method

Signed-off-by: Al Viro